I'm glad to see discussion on the penultimate post since it has been heavily distracting me all the past two weeks!
I don't have KSP, and doubt it would run on my current platform if I had it, so a lot of caveats and qualifications confuse me. I gather that in its default mode, the Kerbal planet and Kerbals themselves are smaller than Earth and everything operates in a sci-fi alternate system where space travel is easier, and probably the technology modules provided, and most add-ons, are not realistic for real Solar System conditions (or in any possible location of our Universe, in some cases.
) But one can purchase or otherwise acquire add-on mods purporting to make it more realistic. Still, it doesn't prove much of anything if something works in KSP--or if it doesn't.In the real world, how hard would it be to guarantee that, provided one's reentry capsule were reasonably robust, any failure of non-reusable, orbit-only modules to separate as designed would be survivable due to the structural elements attaching them being guaranteed to melt off or burn up before the entry module was subjected to dangerous exposures? How much of the risk is the entry module being sent into a spin or some such, versus being ripped apart, versus being attached to something that is probably ablating rather explosively?
OTL a number of early space missions were threatened by the refusal of disposable parts to come loose on schedule, but generally they came apart in reentry anyway and left the entry vehicle free and sound.
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I want to thank nixonshead in particular for clarifying something, with the illustrations, that has never been explained to me before, and that is the meaning of a "biconic" capsule as the authors intended it.
I've been tripped up by customary OTL spacecraft jargon before, such as the distinction made between "aerocapture" and "aerobraking" that seems counterintuitive to me and therefore impossible to remember, leading me to use circumlocutions to avoid either term. But as far as I can tell strictly speaking, "biconic" is a term for any object that incorporates sections of two different cones in any way. If we were to simplify a sketch of a Soyuz headlight-type capsule by using a polygon to define its vertical cross-section (think late 1970s computer graphics, with objects sketched by a few straight lines) it would be represented as a bi-conic, that is a relatively wide angle cone mated to the truncated base of a narrow-angle cone, with a pentagonal cross section. It would indeed be a biconic object (if you made a real model to match the sketch) but it would presumably reenter just the way a Soyuz capsule does, circle-side down, bearing the heavy TPS. Like a Soyuz capsule or a conical American capsule, and unlike a sphere, it would gave some dynamic lift if the capsule were angled so the slipstream came in a bit off-axis. "Biconic" merely describes that it has conical sides.
As far as I could discern in prior offhand references to "biconic" capsules, they too would be meant to enter with the circular, or perhaps elliptical, cross-section "down" and being the main TPS surface; I gathered some of them might involve skewing the central axis of the cones to the "vertical" defined by the TPS surface being flat, or even skewing the two cones differently, and figured all talk of this improving the hypersonic lift/drag ratio and so forth referred to effects on the afterbody airflow.
It is nixonshead's pictures alone that clarify that whether "biconic" refers to all double-cone bodies in general or is reserved for a peculiar class of them in astronautical jargon, this biconic differs radically in that instead of entering with the circular section down, it enters "on its side," with one strip of its conical surface being turned to the slipstream, and thus an entire half of its conical surface is exposed more or less directly to the hypersonic blast. "More or less" because the parts near 90 degrees away from the "down" strip would be getting it at an oblique angle, but of course not only the air incident on that limb but also all the air coming in between it and the central strip would have to flow past it, so the blast is different in character from what hits the dead center of a traditional almost-flat circular capsule bottom, similar to what flows around the edges of such heat shields to form the afterbody flow. And unlike conical capsules, the afterbody only curves away from that flow gradually at first; the break is sharper even on a Soyuz-type headlight shape, and sharper still on a NASA style conical capsule; such flows resemble the flow around the spherical Vostok capsules more, at least in the plane perpendicular to the cone axis. (Or other planes, diagonal to that axis, along the flow vector of the incoming hypersonic air--the forms the flow goes around there would be elliptical instead of circular). So clearly the sides need good protection too, and aside from the temperature and density of the flowing air remaining high (perhaps reduced by Bernoulli effects but still hot and dense) after passing the "terminator" as seen by the incoming air, the craft might also roll a bit off that central strip, so the heavy TPS needs to be extended for more than 180 degrees of the cones' circumferences. The entire nose cone down to a certain distance down the axis will need complete coverage, and the rear circle (probably still a section of a sphere as on most "flat-bottomed" capsules) will also need heavy protection, perhaps a lot lighter than if it were the main entry surface but still pretty good, because that surface will also be exposed to direct incoming flow though at a glancing angle.
So it is not entirely clear to me just how this is supposed to be vastly superior to the traditional circle-down approach; it seems clear that a rather higher portion of the whole surface must be high-heat bearing, which must penalize the weight somewhat.
Perhaps, especially on elongated ones where the length--the "height" of the two conical surfaces--is greater than the diameter of the "base" disk, we get the benefit of a larger net area and thus less intense heating of any particular unit area section--this won't save overall weight since the area to be covered is greater, but for materials of given capabilities it might improve the safety margin attainable, which is clearly a good thing. But the version NASA was considering in this ATL is not elongated like that and so the directly exposed cross-section is very similar to the circle-base area--the heat load is spread out over a greater area which is good for radiative heat dissipation I guess, but correspondingly heavier.
I gather the major advantage is supposed to be in lift options available.
I have not been able to find any clear and comprehensive discussion of the general comparisons of such "sideways" biconics compared to traditional circle-side-down capsules; I did stumble across a Google book search page (Basics of Aerothermodynamics
By Ernst Heinrich Hirschel) that showed an attempt to compute a proposed biconic's hypersonic lift/drag polars (including pitching moment) but the plot of data, while suggestive, cut off around 60 degrees. I assumed the practically sinusoidal lift curve, which peaked around 40 degrees, would continue past the plot shown and hit zero around 80 degrees. When I think about it though I'm not sure there would be zero before 180 degrees though perhaps a non-zero minimum-or it might indeed cross the axis and be negative before rising back to zero at that angle. I think it clearly must be zero when the flow is parallel to the axis since the body has radial symmetry. Tipping it as far as 90, or even 80, degrees, would expose the tail-end circle to direct flow and presumably change the overall polar considerably at that point.
These plots suggest though that the planned entry flow would be around 40 degrees, right near the peak lift, where the pitching moment also goes to zero. Even if a range of negative lift exists at angles above 80 degrees I think the design would avoid that range.
A traditional circular-base-first capsule would have zero lift when the axis is aligned with the slipstream; by tilting the capsule in any direction "lift" forces transverse to the slipstream would be created. I don't know if the pitching polar would tend to increase the pitch (positive feedback) or reduce it (negative feedback) but I know that capsules in general are always designed with the internal mass distribution such that the center of mass is shifted "down" toward the heat shield, giving a pendulum moment that tends to center it--and also on Apollo and Gemini and I would guess Soyuz, shifted off-axis toward one side to bias it to a certain pitch that yields a standard lift.
Presumably on a side-entry biconic, the center of mass is well off the axis toward one side, toward the center of TPS strip in fact, to guarantee that no matter how the nose is pitched the side of the circular cross-section that is heavily shielded will roll toward the stream; the weight of the TPS itself might do much to guarantee this. And lengthwise, along the axis, the CM would be adjusted to combine with the pitching moment to be stable at the angle yielding the desired lift coefficient.
So it bothers me that the zero-pitch-moment angle appears to coincide with maximum lift; it would seem this biconic (which is quite different from the one in the post, being longer in proportion by far) is designed to enter at maximum lift, and there is no option for raising it should the craft be entering with insufficient lift. One could lower it by pitching in either direction; going to higher angles would also raise the drag and the net combined force vector would rise (but gently) and presumably the heating as well. Going to lower angles would lower both forces but trying to avoid excessive heat or acceleration at any one moment that way would put the axis more nearly aligned with the flow, meaning that the upper side of the conic would be more exposed.
If they wanted high negative lift--say the craft were entering the atmosphere too shallowly and was in danger of bouncing off into an undesired orbit--they could roll the thing around the axis of the slipstream so the nose is down instead of up; a circle-side-down capsule would do that by tipping across the neutral axis to tip the other way.
I don't know if the sideways biconic's lift/drag characteristics as I've described them here would actually be more desirable than the simpler sketch of a disk-side-down capsule; it seems we trade off a higher attainable lift coefficient for greater difficulty in varying it. Intuitively it does seem to me it would be easier to set up the mass balances inside the biconic to set the pendulum moments where we would probably want them than to get the right balance on a traditional capsule; this issue is one that discouraged me from suggesting a capsule solution to the downmass problem. The question is, can we do without the ability to have emergency increases in lift coefficient (because the natural rest angle of the entering biconic selects for maximum already)--do we then have adequate control?
I did also note, in searching for OTL examples of biconic-sideways real or proposed, that it seems normal on such proposals to include some kind of flap on the trailing edge (where the conical sides meet the circular surface, on the bottom, slipstream side). Presumably then in addition to shifting masses internally (a costly method I'd think) or using attitude jets (suitable for quick realignments but not to sustaining an angle offset from the natural product of aerodynamic pitching moments and pendulum moment, unless we have lots of reaction control fuel) the flap can also be moved, which will change the characteristics, most importantly here the pitch moment, to adjust the angle it wants to hold. Obviously such a flap would be exposed to very high heating and must endure high temperatures while still being maneuverable, but OTL we are familiar with this problem on the STS Orbiter.
One rarely if ever sees this suggested for traditional disk-side-down capsules, although I believe one of the early competitive company bids for Apollo included a conical capsule much like the one Faget and von Braun wanted in the first place, but with flaps included.
On a disk-down capsule, even if one side of the capsule were designated as the preferred "leading" edge, I'd think more than one flap would be needed for adequate control. On the sideways biconic I suppose just one can do in a pinch, though the proposals I've seen mention it being split presumably to provide some yaw control as well as pitch. On the biconic though I suspect yaw headings would tend to be stabilized by the flow and thus bursts of thruster fire would be adequate, being brief; it is maintaining various pitch angles I'd worry about with that method since anything off the fixed pendulum/aerodynamic rest angle would require constant thrust to hold.
Now that I've come to finally understand what is meant by "biconic" in the sense shown here, I can see that other proposals I've seen before are also in this category, such as Kliper--particularly the wingless versions, though I'd describe winged Kliper as a mere modification of the basic biconic theme, just as Spiral's spaceplane was essentially a lifting body with wing/fins added for control and low-speed lift. It is much clearer to me why the space travelers (ESA also toyed with the idea, so I'm not just saying "cosmonauts) had acceleration couches with their backs to the pointed tip--at angles like 40 degrees off a zero defined by that tip, the net forces would be "backward" like that, with "down" toward the nose, though the high lift force would tend to shift it toward the TPS side.
One idea I had, especially for a wide, relatively short length version such as NASA considers ITTL, was for the crew compartment to be a rotating drum, with its axis at 90 degrees to both cone axis and the plane in which the circular circumference of the conical surfaces would be centered against the slipstream. The drum could be rotated so as to put the crews' backs downward across the rocket axis during launch, and then relocated some 120 degrees away to have their backs facing the net reaction during nominal entry, and able to shift back and forth as the craft undergoes necessary pitch changes--I haven't quite worked it out in my head but it seems to me this would introduce a moving mass that would shift the net center of mass forward or aft to support holding lower or higher pitch angles; if so the drum's internal mass distribution could be designed to accentuate this shift, putting heavy equipment within it under the crew couch backs or anyway alongside them. If I'm mistaken and the shifted mass destabilizes things, that same stuff can be placed opposite the crew to balance the drum, though it becomes less desirable then and its obvious liabilities tell against it more strongly.
One such liability would be that the drum would have to be rotated a certain way to give access to any parts of the spacecraft not included in it; it would be bad if it jammed in the wrong position. Also we'd want it oriented right at least for average reentry if not freely rolling to provide optimal g-force mitigation; that should be the standard orientation. The biconic proposals I've seen suggest putting a hatch on the "top" side of the conic, that is opposite te TPS center; with a drum it would have to be on the drum axis which is to say, on the side, where it might take on water if the thing lands in water.
I suppose such a drum would be too extravagant, but without it I suspect the crew will have an odd time of it, if not actually unpleasant, reentering with widely shifting net "downward" vectors--I suppose the easier answer would be to mount the couches along that "drum" axis individually so they can swing separately like so many hammocks. Now they are sideways to the flight direction instead of backwards to it, which might create more confusion for pilots trying to control it.
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I've also had the chance to reflect on how this version of lifting-body, sideways biconics might apply to other problems, such as achieving reusable second stages. The consensus of this TL seems to be that when reusable first stages will be achieved, it will be by means of vertical-landing rockets. My chief difficulty with that idea is that although it is typically the upper stages that contribute most of the necessary transverse velocity to actually achieve orbit, the first stages have historically still contributed a significant amount of it even so; to change launch profiles to reduce that downrange boost throws a heavier burden on the upper stages. But to retain the traditional modest but significant downrange velocity contribution of the first stage makes return to base on rocket thrust problematic because that downrange velocity must be arrested quickly and reversed. Reversing it is not such a major part of the task because the stage will also impart a lot of upward velocity, which buys time to make the distance back to the launch point, and I guess it is not necessary to cover that whole distance before falling back to the first-stage burn cutoff altitude, since it will cover some more of it in the atmosphere on the way all the way down. So that extra velocity is relatively low, but cutting a downrange speed of say 2 km/sec will require significant fuel masses, which can be regarded as a multiple of the empty mass fraction and thus an increase of "empty" mass fraction for the launch phase, which drives up the mass relative to the upper stack considerably.
OK then, assuming we can pay whatever price it takes (distributed between the first and upper stages) and solve the problem of returning the first stage this way or some other--how to get back the upper stages? Say it only takes one other stage; the goal is to get to orbital velocity, so that, or nearly, is where that stage winds up. Clearly it could orbit around the Earth and come in toward the launch site, much as any returning space capsule or the like eventually will. But what then? Unlike a rocket-returning first stage that might need essentially no TPS or even a winged or other flyback form that will need only a fraction, going at a low fraction of orbital speed as it will, it will face the same stringent requirements a return capsule does, and to be reusable an ablative coating is probably not practical since it would have to be reapplied for a second mission.
Do biconic lifting bodies coming in sideways offer solutions that help broaden our options usefully?
Given that the engine will be a big part of the mass of any returning upper stage, and must be located on the tail end of a compact body (conceivably there could be two sets on the wing tips of a winged body, straddling center of mass a la Skylon, though thrust structure might be problematic and so would be thermally protecting those exposed pods) I guess the biconic-sideways solution would require, not only extensive TPS covering over half the upper skin, but an elaborate scheme to detach the engines and slide them up a tunnel in the tankage to rest halfway along the length of the stage or more, on the TPS side. The stage would not have its mass along the axis of the cones even at launch, with the biases imposed by TPS (unless we can afford to cover the whole surface uniformly) and an offset tunnel, and the shift would become more pronounced as the burn proceeded, so the engine would have to be correcting for a shifting center of mass constantly.
It seems maybe a traditional disk-down body, with the engine or engines mounted symmetrically and either drawn into protective bays with heavy TPS hatches closing to protect them, or the engine nozzles being designed to take the full heat of reentry (after all they have to survive the heat of thrusting) and the craft entering bottom-side down and then landing as the first stage does on rocket thrust and deployed legs might be more practical after all. Even if the engines still have to be moved, stowed for reentry, they don't have to move far and not through the volume where we want fuel tanks to go. The problems I see here are, first of all, the bottom disk is not all that large compared to the total empty stage mass (especially if we need reserve propellant for landing) so it would be intensely heated, whereas a simple cylinder with straight vertical sides would probably suffer pretty severe heating too. I'd be confident it would maintain a generally tail-first attitude due to the weight of the engines, but it would probably wobble somewhat meaning one side another of the tankage cylinder gets exposed to hypersonic heating.
Perhaps with good enough TPS and the reflection that the total empty mass is not tremendous we can get away with this? A tapered cone like say the Mercury or Gemini capsules seems like a better solution though. At a 15 degree angle of mold line to axis, similar to those capsules, I guess in my head that such a cone about 16 meters high and with an 8 or more meter diameter base could hold enough volume to match the TTL Saturn Multibody standard upper stage's capacity; with a base area of over 50 square meters, could its dry mass still be kept down in the close ballpark of 10 tons, with enough margin for adequate TPS on the main shield and any gadgetry necessary to protect a single engine in the J-2S class, or a cluster of say six of one-sixth that engine's thrust? Bearing in mind the two American crew capsules of the early and mid 60s needed substantial TPS on their upper bodies as well, a high-temperature metal shingle? My guess is the pressure and thus heat flux on the surfaces will be a tenth or less that on those two capsule's shields, but on the other hand they used ablative main shields.
Anyway, with a 4 or more meter radius, the bottom of such a stage would be enormous compared to any real-world rocket structure diameter (except maybe the STS fuel tank or Energia core tankage); since Saturn Multibody standard first stage units have the same diameter as the standard upper stage I guess a new version of the tankage to merely match the 8 meter diameter bottom would have a quarter the height or less; separated from the hydrogen-oxygen upper stage it would look rather like a hockey puck if not a pancake!
Well, it might look silly, but such a form might be just fine for rocket-landing return, if it can be stabilized to keep the bottom side down.
The upshot is rockets that look more like flying Gemini capsules, with the first stage as the Transstage and upper one as the capsule itself, and the payload as the nose cylinder. The air drag on the way up might be pretty significant. Then again I believe NASA or anyway someone seriously proposed these sorts of monsters back in the 1970s, and what I'm describing is probably much like many of Bono's proposals for fully reusable single-stage orbiters in the million-pound payload range--except that they aren't single stage of course. But fully reusable!
The biconics on the side don't seem to come into it unless someone has severe objects to the simple tail-down entry solution and can face the issues of moving the mass of the engines to a suitable location inside. It would seem that the old-fashioned winged spaceplane is a better contender than biconics for this role, if it is possible to mount the main engines on the wingtips and for them, the wings, and the spindle-shaped fuel tank in the middle to have adequate TPS--which seems not so crazy considering their extended area when coming in belly-on.
Give KSP a chance, its 'just' a game after all.I'm glad to see discussion on the penultimate post since it has been heavily distracting me all the past two weeks!
I don't have KSP, and doubt it would run on my current platform if I had it, so a lot of caveats and qualifications confuse me. I gather that in its default mode, the Kerbal planet and Kerbals themselves are smaller than Earth and everything operates in a sci-fi alternate system where space travel is easier, and probably the technology modules provided, and most add-ons, are not realistic for real Solar System conditions (or in any possible location of our Universe, in some cases.
But with there are mods (ALL of them are free) to make it much more realistic. Real Solar System, makes the Kerbin system realistically scaled (6.4x RSS scales everything up to 6.4 times the original size, with the Sun being a K class star), Deadly Reentry introduces realistic reentry with the change of burning up, or killing your Kerbals with too much G-forces, FAR uses almost realistic aerodynamics (making ascent rather fun if you manage to get the right gravity turn), Real Fuels introduces actually used fuels, from Kerolox over Hydrolox to Hypergolics.
Orbital mechanics are realistic enough with two body math and patched conics, though there is an N-body mod in the works, IIRC.
Either way, I have been able to deal with disconnecting the orbital module. The only problem now is to keep the reentry module on the very, very tight reentry path. Wou have to stick to or the aerodynamics WILL flip you around and it WILL explode.
Hi all. For this week's illustration, we take a look at Luna-Pe, as the first mission is unloaded by astronauts from the "Soonbase".
BTW, I love the dynamic of Russian cosmonauts having no choice but to barter for spare seats on US spacecraft!
BTW, I love the dynamic of Russian cosmonauts having no choice but to barter for spare seats on US spacecraft!
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here OTL version of Luna-Glob lander as of the end of 2010.
left Lunar Rover and right Sample return mission
left Lunar Rover and right Sample return mission
Nixonshead, would it be possible to get orhographic views of the crafts from parts III and IV, like you did for the part II crafts?
Like this?
A lot of the new stuff for the past couple of parts have been unmanned or launchers, so I've not tended to do orthos of those. But if you have requests, feel free to make them!
Yes!
Hmm, I'd like to see Longxing, Mir w/Tiangong, ACV, the MTRs, the Artemis Rovers, Luna-Pe, Cryosat, and all the rockets in a chart like this:
EDIT: Holy darn that's a big image. anyways, I would also like to see orthos of the crafts from Kolyma's shadow.
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You've mentioned a Soviet/Russian multiple NEO mission before but I don't recall you expanding on it. Did this evolve into Piazzi or is it something else? On the matter of NEO missions though, we haven't heard anything from the Fukurō or Barnard comet missions in a while...
The Luna-Pe is an interesting concept, I'm presuming it only needs a Vulkan/Blok-R to push it through TLI?
Most of those shouldn't be too much trouble, though the level of detail on the ACV, Cryosat and rovers is pretty low. I'll put them down as background tasks and try to trickle them out over the next few months.
For the rocket chart, we have already the 'rocket park' image, which I update from time-to-time as new launchers appear. It could be due for an update before long as Thunderbolt and... other things make an appearance, so I could change the format to something similar to that poster (though perhaps a bit smaller!).
For Kolyma, I'm hoping to get a few more craft modeled over the hiatus (Columbia, Safir, Starlab and Chasovoy mainly), so I'll look at making orthos as they get built.
I did expand on it, here. It failed shortly after launch, so there wasn't much to expand on. Piazzi was a completely separate mission begun by ESA in the 1980s that was aimed at main-belt asteroids (mostly).
As for Fukurō and Barnard, information on them is coming at the appropriate time.
Yes, it's very much smaller than the Artemis landers. It was built to have a surface payload of about a ton, a ton and a half; enough for a decent-size rover with some sample-collection equipment and the ascent rocket. The mass ratio for a direct descent is a bit less than two, so that works out to around 4 tons of mass that needs to be sent through TLI, while Vulkan/Blok-R can put about 8.7 tons through TLI. So it all works out.
Part IV, Post 15: Artemis 10 and 11, plans for Orion
Good afternoon, everyone! Last week, we reviewed the state of the Russian unmanned program, and some of the leadup to their participation in the Orion outpost. Today, we're looking at the development of the US program over the same period, reacting to President Woods' goal of a cheap, fast lunar outpost, and plans for the future...
Eyes Turned Skyward, Part IV: Post #15
Between Ann Richard’s approval of four additional Artemis missions to continue the lunar exploration program and her sudden exit from the White House following the 2004 election, NASA’s human spaceflight program had operated on the tacit assumption that such renewals would continue to come in the future, with lunar missions continuing to be approved on an irregular basis for a roughly constant annual flight rate, much as Spacelab and Freedom operations had been funded for almost a quarter-century. It was with this assumption in mind that Artemis 7, 8, and 9 had been dispatched on their extended exploration of the lunar farside and the South Pole/Aitken Basin. assuming that future missions would enable sorties of similar extensiveness could be spread across the rest of the lunar surface. With this survey complete, other targets had suggested themselves--potential volcanic sites similar to those explored on Apollo 18, the lunar North Pole, potential lava tube sites, major lunar craters, or returns to re-examine Apollo landing sites in the far greater depth which Artemis missions allowed.
The first of this second round of sorties, Artemis 10, launched in 2005 towards the lunar crater Copernicus, a major feature on the lunar nearside. Given the limits of orbital and Earth-based survey, the age of features on the lunar surface was in general known mostly by relative dating. This practice, commonly used on Earth prior to the development of radiation dating, involved comparing layering of rocks, fossils, and features to build a relative timeline of selenological history, even if specific dates couldn’t be known. Similar relative dating was possible even from lunar orbital imagery: a crater whose ejecta or features was overlapped by another must have come first of the two, and through charting ejecta and other features, a comparative history of the lunar surface. The crater Copernicus served to characterize a major period in selenological history, dating from roughly 1.1 billion years ago to the present. Efforts on both Apollo 12 and Artemis 4 had been made to sample possible Copernican ejecta material, but the results were sketchy, and thus dating it conclusively through an in-depth exploration would serve to better tie down dates for much of the most-recent period of lunar history, as well as the usual interest in craters as “natural boreholes” in the lunar surface. Similar explorations of other sites like Mare Imbrium, the Mare Nectaris, and Mare Orientale (the lunar surface’s most recent large basin) promised to complete a more detailed picture of the geological history of both the Earth and the Moon, but were to be mixed with other missions over the coming years, part of creating a diverse but increasingly complete picture of the nearest astronomical body.
The replacement of President Richards with President Woods seriously upset these plans. Even as the launch of Artemis 10’s cargo lander Helios proceeded in early 2005 to begin the leadup to the traditional summer lunar flight, the President and his chosen replacement for the now-retired Administrator Davis, Dean Banks, were charting a new course for lunar exploration. Though the central concept of roughly-annual lunar missions would stand, the new “Orion” lunar outpost based on the so-called “soonbase” concept would see future lunar flights making repeated visits to a single base site, though of longer duration and equipped with the tools for ranging further than ever from their initial landings site, enabling the study of a specific area of the lunar surface in far greater detail than even an Artemis sortie allowed. However, this Orion outpost--planned to be launched in 2007 and first visited in 2008--would mean that Artemis 10 and 11 would be the final lunar missions for some time to visit “terra nullius” and break new ground. This was particularly true after the decision was made in late 2005 to focus Orion’s landing site on Crater Shackleton at the lunar south pole, a known source of valuable lunar volatiles--access to which was a part of plans to demonstrate more sustainable lunar resource utilization for future full-time bases. Thus, Artemis 10 and 11 abruptly became not the start of a new series of wide-ranging Artemis sorties, but the last for the foreseeable future.
Though the final decisions hadn’t been made when when the Artemis 10 crew touched down at Copernicus, the writing was on the wall. The crew was commanded by astronaut Russell Jackson--the first African-American to command a lunar landing. However, he was also an exception in other ways. Though he was a veteran astronaut, with two flights to Freedom under his belt, unlike previous Artemis commanders Jackson had neither commanded a Space Station Freedom Expedition (unlike Hunt, Valente, Altman, or Quick) nor had he flown previously on an Artemis flight (unlike his immediate predecessor Natalie Duncan of Artemis 9), part of a new NASA policy for Artemis mission selections aimed at preventing a rise of separate groups of “lunar bound” and “station bound” astronauts. Jackson’s crew touched down at Copernicus in the Hyperion in September 2005, and set about extensive exploration of the crater site, including formations near the crater’s rim area believed to be the result of lava flows, and the crater’s three large central peaks. Also on the schedule were investigations of smaller hills and wrinkling in the crater’s floor--unlike many such large craters, Copernicus’s basin had seen only small amounts of lava infill after its formation, and thus had a rich selenological bounty at its bottom, including small hills on the smoother portions of the crater floor which had been believed at one point to be volcanic in origin.
The drive to define the “age of the crater” led to a wide-ranging survey of the exposed crater bottom, with the crew carrying out several rounds of core drills and attempting to penetrate the surface regolith in order to expose material for a precise radiodating of the crater. In addition, the crater’s central peaks saw repeated, extended examination, sampling for confirmation of the elevated levels of olivine detected by previous orbital missions. Stretching roughly 80 km in diameter across its rough hexagonal shape, Copernicus was near the upper limit of the area which could be covered from a single landing site, and the crew ended up putting some of the highest totals on their rover odometers ever seen in pursuit of the most exhaustive survey of the site possible, even as attention within NASA turned from the active landings on the surface to plans for the future.
By the time the Hyperion’s crew splashed down in the ocean off Hawai’i, work at NASA to better define the Orion lunar outpost was proceeding at a furious pace. With the passage of the 2005 NASA Authorization Act, “soonbase” was the official NASA program of record to succeed Artemis, and the goal was a launch using the Artemis 12 and 13 hardware no more than two years away if possible. Given plans for Artemis-derived long-duration missions had been in development for some time, the program wasn’t beginning from a complete standing start, but the timeline was still ambitious. The outpost would, in general, make use of three primary new technologies, among other minor modifications and improvements to the Artemis system.
First and foremost, the pressure hulls of the Orion outpost’s habitat lander would be modified, adding an additional two-and-a-half meters of “barrel” height to the rigid portion of the habitat to make room for a second story, enabling the expansion of onboard life support and research space in the habitat lander. The wardroom, galley, and primary water-circulation systems were moved to the new “mid-deck” of the habitat, allowing room for a closed-loop water recycling system based on that in use on Space Station Freedom, which would dramatically reduce the daily consumables requirement for the crews as well as a demonstration unit of a lightweight, compact combination washer/dryer unit, enabling the crew to minimize the number of changes of clothing required during multi-month lunar stays. In the space vacated by the galley/wardroom and hygiene station on the lower level, Orion would have expanded power and air circulations systems, radiation shielding, and an expanded laboratory, now separated from the airlock by a “foyer” to further reduce dust levels. In addition to geological study, the new lab could also be used for biological and physics experiments using modules brought from Earth, as on Freedom, and also included provisions for exercise equipment to reduce the effects of extended reduced gravity, again similar to units in use on Freedom. The crew’s personal bunks, desks, and other spaces were planned to remain in an inflatable dome on top of the new mid-deck, making for a much more spacious habitat.
Secondly, the Orion crew would have access to a new design of rover. The Apollo-type “open-cockpit” unpressurized rovers which had been in use on Artemis (two of which remained at the Artemis 9 site, and were considered for re-use on Orion) had two major benefits. First, they were lightweight, a boon for the limits of the Artemis sortie strategy. Second, the crew could easily stop and hop off the rovers at a site of interest, allowing easy, unscheduled stops at points of interest encountered during traverses. However, they also had a limitation; the crew were required to be in their EVA suits for the entire duration of a rover traverse. Even with “plug-in” ports to allow a supply of spare O2 on the rover to recharge the astronaut’s suit supplies, the crew were limited by NASA EVA duration limits to about 8 hours on the lunar surface. Thus, the maximum distance for a traverse to travel from the Artemis mission’s habitat was the duration that could be travelled in four hours--about 40 kilometers, though the more common “turn-back” distance was lower. Switching to a heavier rover with a pressurized cockpit would allow the crew to “camp out” at remote sites over traverses lasting multiple days, expanding the area in reach of Orion by an order of magnitude--viewed as a critical enhancement to an outpost which would see crews spend as much time on the ground as every previous Artemis mission combined.
Third and finally, the space suits used by Orion would be altered. This change was aimed at minimizing the time lost in donning and doffing of suits and retain some of the flexibility of EVAs in the open cockpit rovers, the new rovers would also use a new kind of suit, the Articulated Lunar Excursion Suit. The existing A9L had to be donned in pieces and then checked out in a process requiring as much as half an hour, followed by cycling out through the airlock. In contrast, the ALES used the “suitport” concept developed by NASA over the past decade. In this concept, the entire suit was kept outside the spacecraft’s pressure hull with a back hatch was used to essentially “dock” the suit to a rover or other pressure hull, with the astronaut donning the suit by climbing through a hatch in the rear. Once donned, the back hatch would close, and the crewmember would already be outside. In ground tests in labs and the DREAM practices in the field on Earth, the “suitport” design could allow an astronaut to don or doff their suit in as little as five to ten minutes. Provisions for suitports were included not only in the rovers of Orion, but in the logistics and habitat vehicles.
However, aside from these modifications, much of Orion would remain based on the Artemis system--it would use the same Saturn H03 launch vehicles and Pegasus departure stages, the descent stages would be unmodified, the Mesyat network would continue to be utilized for communications, and many of the ground-side instruments and crew fittings were just to be re-arranged. Once on the lunar surface, the habitat and logistics modules would remain on top of their descent stages instead of introducing the complexity of cranes or large cargo transport rovers. The facility was designed not for continual occupation, like Freedom, but instead for repeated visits on the order of months roughly annually. Nevertheless, the challenge of making the planned late-2007 launch date for the outpost was going to be steep.
Even as Orion was planning for this first lunar outpost, proposals for more heavily modified, more-sustainable landings--true lunar bases--were under consideration, under the rough project name of “Oasis”. This expansion in lunar operations was planned to make use of the developing world of cheap, reusable launch vehicles, attacking the costs of lunar missions literally from the ground up. In an Artemis mission, almost 210 tons of hydrogen/oxygen propellant was utilized in the process of reaching the lunar surface. Even the smaller two-launch, one-lander Orion “soonbase” rotations would still use almost 100 tons of propellant (75 tons in the Pegasus, plus the contents of the Artemis descent stage), mandating the launch of two Saturn Heavies for each mission--one for the crew lander and payload, the other for the Pegasus to push them to the Moon. If the potential for propellant depots could be realized, this propellant could instead be launched far more cheaply by a number of partially or fully reusable vehicles, such as the SLS Thunderbolt or the planned Lockheed Starclipper, while the Pegasus stage could be modified like its smaller Centaur cousin, which was already serving as the core of the cryogenic fluid storage demonstrator which launched early in 2006.
A commercial version of this Centaur-derived depot was also being developed by Northrop’s Transorbital Services, as well as a Centaur-derived tug. Based on this work, Northrop submitted a study to NASA for Oasis calling for the application of these Centaur techniques to a roughly 130-ton capacity Pegasus depot and reusable Pegasus-derived tug. Just as Transorbital’s plans called for a Centaur tug to dock to a satellite in LEO launched by Thunderbolt or Starclipper, then push the satellite through a geosynchronous transfer orbit before firing its engines to return back to LEO and refuel at a depot, Northrop proposed to NASA that a Pegasus tug could meet a Saturn-launched payload stack in LEO just as the current Pegasus did, boost onto a trajectory to L-2, then return to LEO with reserved propellant. The depot could be cheaply filled by commercial LVs--something which Northrop’s study noted would have encouraging effects on the developing RLV market--and reduce the cost of launching an Orion-type crew rotation to L-2 by about a third. Moreover, they proposed that a depot placed at L-2 and serviced by Pegasus or Centaur tugs acting as tankers from LEO depots could in turn allow the same type of tug to perform much of the delta-v of the transit from L-2 to the lunar surface, then return to L-2 to refuel. This would dramatically decrease the delta-v which the actual descent stage would perform, and enable increased payload to the surface at a decreased cost--potentially more than halving the mission cost relative to the Orion system, enabling two missions to the moon with enough consumables to stay at a base for six months to fly each year--enough for a permanently crewed base. As a further development, this reduced delta-v could allow a single-stage lander to not just touch down but also return to orbit for reuse, once more dropping costs and perhaps re-enabling sortie missions.
The proposal met with interest among the Oasis team, answering one of the key questions about how to cheaply execute on a lunar base architecture. However, there was still concern about the true lifecycle costs of depots and the proposed reusable tugs. Moreover, although other concepts were in early stages of work, StarLaunch was currently the sole provider capable of sourcing propellant in LEO for less than $3000/kg. With TransOrbital not set to launch their own depot and tug before 2010, the technology was judged immature for the moment. Still, with Oasis barely in the planning stages and not planned to begin in earnest before the turn of the decade itself, the technology had time, and proposals for alternate versions of tugs, depots, and reusable launch vehicles began to circulate as the idea found root in other providers. Some interesting variants drove the depot propellant flow in reverse, drawing on polar lunar volatiles for reusable lunar shuttles, carrying propellant to L-2, and even to points beyond.
However, in the short term, the biggest question facing US lunar planners was the site selection for Artemis 11, now to be the last sortie mission before the start of the Orion landings at Shackleton. Opinions on the preferred destination for this flight were deeply mixed--some Orion planners wondered about the potential value of sending it to explore a northern polar crater, such as Peary, to investigate if volatiles and other conditions might be better suited there to play host to Orion, while some selenologists hoped to visit another of the major dating craters. Mare Orientale had certain admirers, as like Copernicus the impact which had created it was quite recent and the crater nearly entirely empty of lava at its floor, potentially implying lunar crust less than a kilometer thick below its surface. Still others sought to visit a lunar highlands site, particularly one with volcanic materials, enabling answers to questions about this period in lunar history. Though Apollo 18 had spent 3 days at Hyginus crater in search of some of these answers, the exploration capability of an Apollo mission was small compared to an Artemis sortie. In the end, this final group won out--the last Artemis mission would, like the last Apollo mission, investigate the Moon’s volcanic past, landing among the massive pyroclastic deposits at Rima Bode.
However, before the mission went ahead, outside events intervened that threw a serious wrench into the works of the entire United States space program. In January of 2006, as Artemis 11’s cargo lander was being prepared in Florida, another Saturn rocket lifted off from Vandenberg Air Force Base in California. The Saturn M22 launcher lifted off in a night launch, burdened with a large, classified NRO payload inside its widebody fairing. However, the rocket had barely reached max-Q before the rocket’s plume twitched, then the night was lit up by a massive explosion as the vehicle detonated, burning chunks of the solid rocket boosters cascading down like fireworks around the main fireball as nearly two billion dollars worth of shattered remains of engines, tanks, avionics, and precision optics plunged towards the ground. The spectacular failure--the first mission failure of a Saturn rocket since the breakup of Spacelab 28 in 1986 almost twenty years prior--immediately put the brakes on all other Saturn Multibody launches. Fortunately, the most recent Freedom Expedition crew had launched less than a week prior, and the impact on station logistics was thus minimal for the moment, but until the root cause of the failure could be tracked down by Air Force, Boeing, and NASA investigators, the entire Saturn family was grounded--and with it, Artemis 11.
With so many launches pending--and depending--on the results of the review, the inquiry began in earnest almost immediately. Telemetry was documented, video from pad cameras and public spectators was collected and analyzed, and debris was swept off the bottom of the ocean. Rapidly, the focus of the investigation moved to the vehicle’s port-side solid booster. Upon delivery of the booster to Vandenberg, an anomaly had been identified in the port-side lowermost segment. Prior to stacking, a standard repair process had been followed to correct the potential void, and the stacking process had proceeded normally. However, in-flight, the solid rocket booster had failed at or near this anomaly in the motor’s propellant, cutting through the tank of nitrogen tetroxide used for the thrust-vector control of the motor and rapidly expanding the hole in the casing. Structurally compromised and with a massive throttle imbalance, the aerodynamic forces of max-Q had been enough to finish the job, plunging the mission’s payload into the ocean in a rain of fire and shrapnel. While the ability to mount solid rocket boosters was a capacity the Air Force had requested for Multibody and made substantial use of, NASA had never made the modifications at KSC to make use of the capacity, instead simply using either the bare Medium or tri-core Heavy configuration. Thus, when three months later the problems were conclusively limited to questions of handling the solid rocket boosters (a cost that had been increasing as the Commercial Titan dropped in use), NASA made the decision in association with Boeing to re-certify the Saturn for flight in its liquid-only configurations.
The first task was to catch up on Freedom logistics, including a crew rotation already scheduled for April, then a delayed Aardvark re-supply. These were cleared off the manifest by July, and then Artemis 11 was finally once again readied for launch, with the booster carrying the cargo lander Cutty Sark to orbit in that same landing slot originally planned for the crew landing itself. The landing itself was pushed to a slot in KSC operations in early 2007, delaying operations for the launch of Orion--a delay that was in many was a relief to those preparing the mission for launch, as the compressed timeline for development of the new habitat was proving challenging. In February 2007, the crew of Artemis 11 belatedly lifted off for the Moon.
Rima Bode, in many ways, was an anticlimactic end to the sortie program. Unlike Copernicus, whose crews had taken dramatic shots in and among foothills of the kilometer-tall peaks at the center of the crater or the attention-grabbing farside and polar landing missions of other Artemis flights, the Rima Bode landing site was a relatively flat area of the lunar nearside, characterized more by the massive deposit of pyroclastic materials at the surface than by any dramatic, easily visible terrain. Instead, the interest at Rima Bode was on past volcanic venting events which, in fashion as spectacular as any crater, had blown a layer of mixed volcanic materials tens of meters thick across the region, like many of the great eruptions of Earth. With the extensive probing of the lunar impact history on previous flights--and particularly on the Artemis 10 landing at Copernicus, many selenologists were equally hungry for a the chance to apply the Artemis sortie capacity to a site just as rich in clues about the moon’s volcanic past. Rima Bode offered just such a site, with a variety of surface features exposing gaps in the blanket of pyroclastic materials. Inspection on the surface showed a variety of fine-grained, titanium-rich volcanic glass. Though similar in rough formation to the “orange soil” which had fascinated the crew of Apollo 17 and 18 more than 30 years prior, the material was distinct in composition, with high concentrations of ilmenite and a characteristic black color.
However, the surface wasn’t the only dark turn on the mission--for many selenologists, the chance to explore an untouched, thoroughly new site for the final time drew parallels to Apollo 18’s investigation of the volcanic crater and rille at Hygenius. The Orion outpost was viewed both inside and outside NASA as a large step forward in the exploration of the moon, and in terms of stay time and traverse capacity this was true, but some selenologists saw the volatiles in Shackleton as a tether that they couldn’t range out of reach of, prone to snapping exploration and bases back to regions near it. In their view, Artemis 11 could be the “last new site on the Moon” for quite some time, though the attitude wasn’t universal. Mission commander Brian Oliver took particular exception to it, and staged a stunt to this effect. Among the personal possessions he carried to the moon, he revealed his own, personal copy of the first edition of 2001: A Space Odyssey, which had been given to him by his father and played a small part in inspiring him to become an astronaut. In the leadup to the mission, Oliver had reached out and managed to get Arthur C. Clarke himself to sign the slightly dog-eared hardcover. As the crew finished the final tasks in the hab before donning their suits, Oliver showed the book to Houston and explained--he was leaving it there in the center of the galley table “for the next crew to come here.” As they waited, he wrote in a short message by hand below Clarke’s, closed the cover, and went to join the others. Post-flight, he would steadfastly refuse to divulge the messages to the press, smiling and saying only, “If you want to know, go read it yourself.”
However, while Artemis 11 closed the book for the moment on one phase of lunar operations, the next launch to the moon couldn’t read anything, because it wasn’t another crew. Instead, at last, the Orion habitat and logistics modules were ready, and in the second half of 2007, first one and then the other Orion Assembly Mission touched down on the rim of Shackleton crater at the new Orion International Lunar Outpost, the descent stages controlling their flight to land barely a few kilometers away from where their Artemis descent stage twins had deposited the Endurance habitat and the Nimrod crew lander on Natalie Duncan’s Artemis 9 flight three years earlier. With the outpost deployed by remote control and the two module’s functionality confirmed, the crew of the first “soonbase” mission stepped up their preparations to inaugurate the outpost...
Eyes Turned Skyward, Part IV: Post #15
Between Ann Richard’s approval of four additional Artemis missions to continue the lunar exploration program and her sudden exit from the White House following the 2004 election, NASA’s human spaceflight program had operated on the tacit assumption that such renewals would continue to come in the future, with lunar missions continuing to be approved on an irregular basis for a roughly constant annual flight rate, much as Spacelab and Freedom operations had been funded for almost a quarter-century. It was with this assumption in mind that Artemis 7, 8, and 9 had been dispatched on their extended exploration of the lunar farside and the South Pole/Aitken Basin. assuming that future missions would enable sorties of similar extensiveness could be spread across the rest of the lunar surface. With this survey complete, other targets had suggested themselves--potential volcanic sites similar to those explored on Apollo 18, the lunar North Pole, potential lava tube sites, major lunar craters, or returns to re-examine Apollo landing sites in the far greater depth which Artemis missions allowed.
The first of this second round of sorties, Artemis 10, launched in 2005 towards the lunar crater Copernicus, a major feature on the lunar nearside. Given the limits of orbital and Earth-based survey, the age of features on the lunar surface was in general known mostly by relative dating. This practice, commonly used on Earth prior to the development of radiation dating, involved comparing layering of rocks, fossils, and features to build a relative timeline of selenological history, even if specific dates couldn’t be known. Similar relative dating was possible even from lunar orbital imagery: a crater whose ejecta or features was overlapped by another must have come first of the two, and through charting ejecta and other features, a comparative history of the lunar surface. The crater Copernicus served to characterize a major period in selenological history, dating from roughly 1.1 billion years ago to the present. Efforts on both Apollo 12 and Artemis 4 had been made to sample possible Copernican ejecta material, but the results were sketchy, and thus dating it conclusively through an in-depth exploration would serve to better tie down dates for much of the most-recent period of lunar history, as well as the usual interest in craters as “natural boreholes” in the lunar surface. Similar explorations of other sites like Mare Imbrium, the Mare Nectaris, and Mare Orientale (the lunar surface’s most recent large basin) promised to complete a more detailed picture of the geological history of both the Earth and the Moon, but were to be mixed with other missions over the coming years, part of creating a diverse but increasingly complete picture of the nearest astronomical body.
The replacement of President Richards with President Woods seriously upset these plans. Even as the launch of Artemis 10’s cargo lander Helios proceeded in early 2005 to begin the leadup to the traditional summer lunar flight, the President and his chosen replacement for the now-retired Administrator Davis, Dean Banks, were charting a new course for lunar exploration. Though the central concept of roughly-annual lunar missions would stand, the new “Orion” lunar outpost based on the so-called “soonbase” concept would see future lunar flights making repeated visits to a single base site, though of longer duration and equipped with the tools for ranging further than ever from their initial landings site, enabling the study of a specific area of the lunar surface in far greater detail than even an Artemis sortie allowed. However, this Orion outpost--planned to be launched in 2007 and first visited in 2008--would mean that Artemis 10 and 11 would be the final lunar missions for some time to visit “terra nullius” and break new ground. This was particularly true after the decision was made in late 2005 to focus Orion’s landing site on Crater Shackleton at the lunar south pole, a known source of valuable lunar volatiles--access to which was a part of plans to demonstrate more sustainable lunar resource utilization for future full-time bases. Thus, Artemis 10 and 11 abruptly became not the start of a new series of wide-ranging Artemis sorties, but the last for the foreseeable future.
Though the final decisions hadn’t been made when when the Artemis 10 crew touched down at Copernicus, the writing was on the wall. The crew was commanded by astronaut Russell Jackson--the first African-American to command a lunar landing. However, he was also an exception in other ways. Though he was a veteran astronaut, with two flights to Freedom under his belt, unlike previous Artemis commanders Jackson had neither commanded a Space Station Freedom Expedition (unlike Hunt, Valente, Altman, or Quick) nor had he flown previously on an Artemis flight (unlike his immediate predecessor Natalie Duncan of Artemis 9), part of a new NASA policy for Artemis mission selections aimed at preventing a rise of separate groups of “lunar bound” and “station bound” astronauts. Jackson’s crew touched down at Copernicus in the Hyperion in September 2005, and set about extensive exploration of the crater site, including formations near the crater’s rim area believed to be the result of lava flows, and the crater’s three large central peaks. Also on the schedule were investigations of smaller hills and wrinkling in the crater’s floor--unlike many such large craters, Copernicus’s basin had seen only small amounts of lava infill after its formation, and thus had a rich selenological bounty at its bottom, including small hills on the smoother portions of the crater floor which had been believed at one point to be volcanic in origin.
The drive to define the “age of the crater” led to a wide-ranging survey of the exposed crater bottom, with the crew carrying out several rounds of core drills and attempting to penetrate the surface regolith in order to expose material for a precise radiodating of the crater. In addition, the crater’s central peaks saw repeated, extended examination, sampling for confirmation of the elevated levels of olivine detected by previous orbital missions. Stretching roughly 80 km in diameter across its rough hexagonal shape, Copernicus was near the upper limit of the area which could be covered from a single landing site, and the crew ended up putting some of the highest totals on their rover odometers ever seen in pursuit of the most exhaustive survey of the site possible, even as attention within NASA turned from the active landings on the surface to plans for the future.
By the time the Hyperion’s crew splashed down in the ocean off Hawai’i, work at NASA to better define the Orion lunar outpost was proceeding at a furious pace. With the passage of the 2005 NASA Authorization Act, “soonbase” was the official NASA program of record to succeed Artemis, and the goal was a launch using the Artemis 12 and 13 hardware no more than two years away if possible. Given plans for Artemis-derived long-duration missions had been in development for some time, the program wasn’t beginning from a complete standing start, but the timeline was still ambitious. The outpost would, in general, make use of three primary new technologies, among other minor modifications and improvements to the Artemis system.
First and foremost, the pressure hulls of the Orion outpost’s habitat lander would be modified, adding an additional two-and-a-half meters of “barrel” height to the rigid portion of the habitat to make room for a second story, enabling the expansion of onboard life support and research space in the habitat lander. The wardroom, galley, and primary water-circulation systems were moved to the new “mid-deck” of the habitat, allowing room for a closed-loop water recycling system based on that in use on Space Station Freedom, which would dramatically reduce the daily consumables requirement for the crews as well as a demonstration unit of a lightweight, compact combination washer/dryer unit, enabling the crew to minimize the number of changes of clothing required during multi-month lunar stays. In the space vacated by the galley/wardroom and hygiene station on the lower level, Orion would have expanded power and air circulations systems, radiation shielding, and an expanded laboratory, now separated from the airlock by a “foyer” to further reduce dust levels. In addition to geological study, the new lab could also be used for biological and physics experiments using modules brought from Earth, as on Freedom, and also included provisions for exercise equipment to reduce the effects of extended reduced gravity, again similar to units in use on Freedom. The crew’s personal bunks, desks, and other spaces were planned to remain in an inflatable dome on top of the new mid-deck, making for a much more spacious habitat.
Secondly, the Orion crew would have access to a new design of rover. The Apollo-type “open-cockpit” unpressurized rovers which had been in use on Artemis (two of which remained at the Artemis 9 site, and were considered for re-use on Orion) had two major benefits. First, they were lightweight, a boon for the limits of the Artemis sortie strategy. Second, the crew could easily stop and hop off the rovers at a site of interest, allowing easy, unscheduled stops at points of interest encountered during traverses. However, they also had a limitation; the crew were required to be in their EVA suits for the entire duration of a rover traverse. Even with “plug-in” ports to allow a supply of spare O2 on the rover to recharge the astronaut’s suit supplies, the crew were limited by NASA EVA duration limits to about 8 hours on the lunar surface. Thus, the maximum distance for a traverse to travel from the Artemis mission’s habitat was the duration that could be travelled in four hours--about 40 kilometers, though the more common “turn-back” distance was lower. Switching to a heavier rover with a pressurized cockpit would allow the crew to “camp out” at remote sites over traverses lasting multiple days, expanding the area in reach of Orion by an order of magnitude--viewed as a critical enhancement to an outpost which would see crews spend as much time on the ground as every previous Artemis mission combined.
Third and finally, the space suits used by Orion would be altered. This change was aimed at minimizing the time lost in donning and doffing of suits and retain some of the flexibility of EVAs in the open cockpit rovers, the new rovers would also use a new kind of suit, the Articulated Lunar Excursion Suit. The existing A9L had to be donned in pieces and then checked out in a process requiring as much as half an hour, followed by cycling out through the airlock. In contrast, the ALES used the “suitport” concept developed by NASA over the past decade. In this concept, the entire suit was kept outside the spacecraft’s pressure hull with a back hatch was used to essentially “dock” the suit to a rover or other pressure hull, with the astronaut donning the suit by climbing through a hatch in the rear. Once donned, the back hatch would close, and the crewmember would already be outside. In ground tests in labs and the DREAM practices in the field on Earth, the “suitport” design could allow an astronaut to don or doff their suit in as little as five to ten minutes. Provisions for suitports were included not only in the rovers of Orion, but in the logistics and habitat vehicles.
However, aside from these modifications, much of Orion would remain based on the Artemis system--it would use the same Saturn H03 launch vehicles and Pegasus departure stages, the descent stages would be unmodified, the Mesyat network would continue to be utilized for communications, and many of the ground-side instruments and crew fittings were just to be re-arranged. Once on the lunar surface, the habitat and logistics modules would remain on top of their descent stages instead of introducing the complexity of cranes or large cargo transport rovers. The facility was designed not for continual occupation, like Freedom, but instead for repeated visits on the order of months roughly annually. Nevertheless, the challenge of making the planned late-2007 launch date for the outpost was going to be steep.
Even as Orion was planning for this first lunar outpost, proposals for more heavily modified, more-sustainable landings--true lunar bases--were under consideration, under the rough project name of “Oasis”. This expansion in lunar operations was planned to make use of the developing world of cheap, reusable launch vehicles, attacking the costs of lunar missions literally from the ground up. In an Artemis mission, almost 210 tons of hydrogen/oxygen propellant was utilized in the process of reaching the lunar surface. Even the smaller two-launch, one-lander Orion “soonbase” rotations would still use almost 100 tons of propellant (75 tons in the Pegasus, plus the contents of the Artemis descent stage), mandating the launch of two Saturn Heavies for each mission--one for the crew lander and payload, the other for the Pegasus to push them to the Moon. If the potential for propellant depots could be realized, this propellant could instead be launched far more cheaply by a number of partially or fully reusable vehicles, such as the SLS Thunderbolt or the planned Lockheed Starclipper, while the Pegasus stage could be modified like its smaller Centaur cousin, which was already serving as the core of the cryogenic fluid storage demonstrator which launched early in 2006.
A commercial version of this Centaur-derived depot was also being developed by Northrop’s Transorbital Services, as well as a Centaur-derived tug. Based on this work, Northrop submitted a study to NASA for Oasis calling for the application of these Centaur techniques to a roughly 130-ton capacity Pegasus depot and reusable Pegasus-derived tug. Just as Transorbital’s plans called for a Centaur tug to dock to a satellite in LEO launched by Thunderbolt or Starclipper, then push the satellite through a geosynchronous transfer orbit before firing its engines to return back to LEO and refuel at a depot, Northrop proposed to NASA that a Pegasus tug could meet a Saturn-launched payload stack in LEO just as the current Pegasus did, boost onto a trajectory to L-2, then return to LEO with reserved propellant. The depot could be cheaply filled by commercial LVs--something which Northrop’s study noted would have encouraging effects on the developing RLV market--and reduce the cost of launching an Orion-type crew rotation to L-2 by about a third. Moreover, they proposed that a depot placed at L-2 and serviced by Pegasus or Centaur tugs acting as tankers from LEO depots could in turn allow the same type of tug to perform much of the delta-v of the transit from L-2 to the lunar surface, then return to L-2 to refuel. This would dramatically decrease the delta-v which the actual descent stage would perform, and enable increased payload to the surface at a decreased cost--potentially more than halving the mission cost relative to the Orion system, enabling two missions to the moon with enough consumables to stay at a base for six months to fly each year--enough for a permanently crewed base. As a further development, this reduced delta-v could allow a single-stage lander to not just touch down but also return to orbit for reuse, once more dropping costs and perhaps re-enabling sortie missions.
The proposal met with interest among the Oasis team, answering one of the key questions about how to cheaply execute on a lunar base architecture. However, there was still concern about the true lifecycle costs of depots and the proposed reusable tugs. Moreover, although other concepts were in early stages of work, StarLaunch was currently the sole provider capable of sourcing propellant in LEO for less than $3000/kg. With TransOrbital not set to launch their own depot and tug before 2010, the technology was judged immature for the moment. Still, with Oasis barely in the planning stages and not planned to begin in earnest before the turn of the decade itself, the technology had time, and proposals for alternate versions of tugs, depots, and reusable launch vehicles began to circulate as the idea found root in other providers. Some interesting variants drove the depot propellant flow in reverse, drawing on polar lunar volatiles for reusable lunar shuttles, carrying propellant to L-2, and even to points beyond.
However, in the short term, the biggest question facing US lunar planners was the site selection for Artemis 11, now to be the last sortie mission before the start of the Orion landings at Shackleton. Opinions on the preferred destination for this flight were deeply mixed--some Orion planners wondered about the potential value of sending it to explore a northern polar crater, such as Peary, to investigate if volatiles and other conditions might be better suited there to play host to Orion, while some selenologists hoped to visit another of the major dating craters. Mare Orientale had certain admirers, as like Copernicus the impact which had created it was quite recent and the crater nearly entirely empty of lava at its floor, potentially implying lunar crust less than a kilometer thick below its surface. Still others sought to visit a lunar highlands site, particularly one with volcanic materials, enabling answers to questions about this period in lunar history. Though Apollo 18 had spent 3 days at Hyginus crater in search of some of these answers, the exploration capability of an Apollo mission was small compared to an Artemis sortie. In the end, this final group won out--the last Artemis mission would, like the last Apollo mission, investigate the Moon’s volcanic past, landing among the massive pyroclastic deposits at Rima Bode.
However, before the mission went ahead, outside events intervened that threw a serious wrench into the works of the entire United States space program. In January of 2006, as Artemis 11’s cargo lander was being prepared in Florida, another Saturn rocket lifted off from Vandenberg Air Force Base in California. The Saturn M22 launcher lifted off in a night launch, burdened with a large, classified NRO payload inside its widebody fairing. However, the rocket had barely reached max-Q before the rocket’s plume twitched, then the night was lit up by a massive explosion as the vehicle detonated, burning chunks of the solid rocket boosters cascading down like fireworks around the main fireball as nearly two billion dollars worth of shattered remains of engines, tanks, avionics, and precision optics plunged towards the ground. The spectacular failure--the first mission failure of a Saturn rocket since the breakup of Spacelab 28 in 1986 almost twenty years prior--immediately put the brakes on all other Saturn Multibody launches. Fortunately, the most recent Freedom Expedition crew had launched less than a week prior, and the impact on station logistics was thus minimal for the moment, but until the root cause of the failure could be tracked down by Air Force, Boeing, and NASA investigators, the entire Saturn family was grounded--and with it, Artemis 11.
With so many launches pending--and depending--on the results of the review, the inquiry began in earnest almost immediately. Telemetry was documented, video from pad cameras and public spectators was collected and analyzed, and debris was swept off the bottom of the ocean. Rapidly, the focus of the investigation moved to the vehicle’s port-side solid booster. Upon delivery of the booster to Vandenberg, an anomaly had been identified in the port-side lowermost segment. Prior to stacking, a standard repair process had been followed to correct the potential void, and the stacking process had proceeded normally. However, in-flight, the solid rocket booster had failed at or near this anomaly in the motor’s propellant, cutting through the tank of nitrogen tetroxide used for the thrust-vector control of the motor and rapidly expanding the hole in the casing. Structurally compromised and with a massive throttle imbalance, the aerodynamic forces of max-Q had been enough to finish the job, plunging the mission’s payload into the ocean in a rain of fire and shrapnel. While the ability to mount solid rocket boosters was a capacity the Air Force had requested for Multibody and made substantial use of, NASA had never made the modifications at KSC to make use of the capacity, instead simply using either the bare Medium or tri-core Heavy configuration. Thus, when three months later the problems were conclusively limited to questions of handling the solid rocket boosters (a cost that had been increasing as the Commercial Titan dropped in use), NASA made the decision in association with Boeing to re-certify the Saturn for flight in its liquid-only configurations.
The first task was to catch up on Freedom logistics, including a crew rotation already scheduled for April, then a delayed Aardvark re-supply. These were cleared off the manifest by July, and then Artemis 11 was finally once again readied for launch, with the booster carrying the cargo lander Cutty Sark to orbit in that same landing slot originally planned for the crew landing itself. The landing itself was pushed to a slot in KSC operations in early 2007, delaying operations for the launch of Orion--a delay that was in many was a relief to those preparing the mission for launch, as the compressed timeline for development of the new habitat was proving challenging. In February 2007, the crew of Artemis 11 belatedly lifted off for the Moon.
Rima Bode, in many ways, was an anticlimactic end to the sortie program. Unlike Copernicus, whose crews had taken dramatic shots in and among foothills of the kilometer-tall peaks at the center of the crater or the attention-grabbing farside and polar landing missions of other Artemis flights, the Rima Bode landing site was a relatively flat area of the lunar nearside, characterized more by the massive deposit of pyroclastic materials at the surface than by any dramatic, easily visible terrain. Instead, the interest at Rima Bode was on past volcanic venting events which, in fashion as spectacular as any crater, had blown a layer of mixed volcanic materials tens of meters thick across the region, like many of the great eruptions of Earth. With the extensive probing of the lunar impact history on previous flights--and particularly on the Artemis 10 landing at Copernicus, many selenologists were equally hungry for a the chance to apply the Artemis sortie capacity to a site just as rich in clues about the moon’s volcanic past. Rima Bode offered just such a site, with a variety of surface features exposing gaps in the blanket of pyroclastic materials. Inspection on the surface showed a variety of fine-grained, titanium-rich volcanic glass. Though similar in rough formation to the “orange soil” which had fascinated the crew of Apollo 17 and 18 more than 30 years prior, the material was distinct in composition, with high concentrations of ilmenite and a characteristic black color.
However, the surface wasn’t the only dark turn on the mission--for many selenologists, the chance to explore an untouched, thoroughly new site for the final time drew parallels to Apollo 18’s investigation of the volcanic crater and rille at Hygenius. The Orion outpost was viewed both inside and outside NASA as a large step forward in the exploration of the moon, and in terms of stay time and traverse capacity this was true, but some selenologists saw the volatiles in Shackleton as a tether that they couldn’t range out of reach of, prone to snapping exploration and bases back to regions near it. In their view, Artemis 11 could be the “last new site on the Moon” for quite some time, though the attitude wasn’t universal. Mission commander Brian Oliver took particular exception to it, and staged a stunt to this effect. Among the personal possessions he carried to the moon, he revealed his own, personal copy of the first edition of 2001: A Space Odyssey, which had been given to him by his father and played a small part in inspiring him to become an astronaut. In the leadup to the mission, Oliver had reached out and managed to get Arthur C. Clarke himself to sign the slightly dog-eared hardcover. As the crew finished the final tasks in the hab before donning their suits, Oliver showed the book to Houston and explained--he was leaving it there in the center of the galley table “for the next crew to come here.” As they waited, he wrote in a short message by hand below Clarke’s, closed the cover, and went to join the others. Post-flight, he would steadfastly refuse to divulge the messages to the press, smiling and saying only, “If you want to know, go read it yourself.”
However, while Artemis 11 closed the book for the moment on one phase of lunar operations, the next launch to the moon couldn’t read anything, because it wasn’t another crew. Instead, at last, the Orion habitat and logistics modules were ready, and in the second half of 2007, first one and then the other Orion Assembly Mission touched down on the rim of Shackleton crater at the new Orion International Lunar Outpost, the descent stages controlling their flight to land barely a few kilometers away from where their Artemis descent stage twins had deposited the Endurance habitat and the Nimrod crew lander on Natalie Duncan’s Artemis 9 flight three years earlier. With the outpost deployed by remote control and the two module’s functionality confirmed, the crew of the first “soonbase” mission stepped up their preparations to inaugurate the outpost...
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So if I've read it right right, the Orion Habs will differ in having 3 floors instead of Artemis' 2 floors with more closed-loop systems. But I have to ask, will they be able to keep it all in the mass margins? IIRC, the standard Artemis was pushing the limits but I could be wrong on that.
And another Saturn Launch Failure? At least there was no crew in it but the question of how to fill the payload void left with the suspension of the SRB-Augmented Saturn LVs is one that I'm sure they'll be asking. Alongside if they might even want those particular variants. I would think they can find ways of going without the M-22 and M-42/3 Saturn Multi-Bodies, but if not, I suspect the SRB vs. LRB Debate might arise again.
And another Saturn Launch Failure? At least there was no crew in it but the question of how to fill the payload void left with the suspension of the SRB-Augmented Saturn LVs is one that I'm sure they'll be asking. Alongside if they might even want those particular variants. I would think they can find ways of going without the M-22 and M-42/3 Saturn Multi-Bodies, but if not, I suspect the SRB vs. LRB Debate might arise again.
It was, but because Orion is semi-permanent instead of being a one-and-run they can cheat by removing consumables and then supplying them later instead of having to have it carry everything it needs from the word go. It's like the difference between Skylab and Spacelab.
Short story: yes, they have a lot of room in the mass margins. Based on NASA studies, the rigid can should mass about 2 tons (hull only), while the "dome" is about 600 kg. The ECLSS is about 3 tons, various other fittings (galley tables, bunks, the lab and airlock, etc) fill another few tons, the consumables are a couple tons, and then there's surface payloads and the rovers, which are another few tons all their own. When the Artemis habitat descent stage hits regolith, it's dropping off 15.5 tons of total payload.
Doubling the rigid can adds about another 2 tons of hull. On the Orion habitat lander, there's also the fitting out weight and increased life support for a tighter closed-loop (another ton, ton and a half), but this is balanced out by that lander not carrying nearly as much in the way of consumables, no surface science payloads, and no rovers. On the cargo lander, there's a lot less in the way of fittings: obviously, the life support can be a lot more stripped-down (that's maybe just a ton instead of 3 tons), there's no bunks or geology lab (just storage racks and freezers for consumables), no hygiene station, and no dome. Both landers end up pretty tight on the margins, but the Artemis system is pretty mature, so riding the edge of the envelope is acceptable.
EDIT: Actually, taking a second look, the volume for the cargo lander doesn't really require the second deck, even if I turn the hull mass savings into more supplies and surface hardware, so I think I'm going to edit the post and change that so only the hab has the additional deck, while the cargo lander uses a single deck rigid can like the original Artemis hab (but still not dome, obviously). It'd fit into the landed mass either way, but with just one deck it delivers a lot more supplies.
Well, the solids will be back, the same way Titan and (of course) Shuttle came back to flight after their own SRB failures, it'll just be slightly longer than the resumption of flights on the M0X and H0X variants. DoD is really depending on the heavy payload of the larger twin-solid Saturns for...unspecified national security missions, and they're probably more interested in returning the system to flight as it stands than switching those to the (much more expensive) tri-core Heavies or investing the funding for smaller LRBs.
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Observations on the new update, which has so much wonderful new stuff that it takes some re-reading:
1) Cutty Sark is a wonderfully romantic name, and I am glad to see it. The Greek mythology names are nice - certainly better than the lame names that recent Martian robots have been cursed with - but it is nice to mix things up with more exotic possibilities. Bob Heinlein would approve.
2) The nod to Clarke was also a nice touch, and probably inevitable - we already know about his contacts with the Apollo astronauts. Eventually, some astronaut on surface EVA is going to spoof Mission Control with a deadpan exclamation about a large black monolith on the horizon...
3) On the M22 disaster, Part A: The spectacular failure--the first mission failure of a Saturn rocket since the breakup of Spacelab 28 in 1986 more than twenty years prior... A small nitpick, but January 2005 is 19 years after 1986, not more than twenty. A very tiny nitpick in a great post.
4) On the M22 disaster, Part B: This has more than a whiff of the Challenger disaster. Intentional?
5) I cannot wait to see some cutaway renderings of the new habitat lander by Nixonshead.
6) If we are talking about multi-month long lunar surface stays, we now need to face the risks of big solar flares. We have far better capability to predict them in the 2000-2010 time frame than we did in 1968-73, but just the same, how does NASA plan to address this danger?
7) Speaking of mission-loss events...with this new look at reusable tugs, landers, and depots, is there any interest at putting in place some kind of genuine resuce capability at L2, or on standby at the Cape - a backup lander, say, in case the one on the surface is disabled? It made less sense with Apollo and Artemis, obviously, but with six month stays, let alone a permanent presence (with all the risks involved in systems sitting dormant on the lunar surface for so lengthy a period of time)?
8) Lastly, I am close to crying over how vast the difference in this reality - so plausible, yet so far away from what we actually DID - is from our timeline. The selenologists crying into their milk over being "shackled" to Shackleton really do not know how good they've got it. But such is the way of these things. Their only basis of expectations is what Artemis has been shoveling their way.
As a side note, however, the plausibility might come in for a question. The word "cheaply" appears in this post. While it wonderful to see NASA taking advantage of the private launch sector opening up to explore fuel depots and tugs, I do wonder if even the NASA of this timeline would place such a priority on cheaply, rather than just lobby for more money it likely won't get to do the same things more expensively - especially when it means more money for certain NASA contractors in certain states and districts. Perhaps, I fear, you are being slightly too optimistic after all. I realize that this is a harder question for a couple of engineers to answer adequately, however.
This is a great update - more food for thought than we have had in a while. Great work, gentlemen.
1) Cutty Sark is a wonderfully romantic name, and I am glad to see it. The Greek mythology names are nice - certainly better than the lame names that recent Martian robots have been cursed with - but it is nice to mix things up with more exotic possibilities. Bob Heinlein would approve.
2) The nod to Clarke was also a nice touch, and probably inevitable - we already know about his contacts with the Apollo astronauts. Eventually, some astronaut on surface EVA is going to spoof Mission Control with a deadpan exclamation about a large black monolith on the horizon...
3) On the M22 disaster, Part A: The spectacular failure--the first mission failure of a Saturn rocket since the breakup of Spacelab 28 in 1986 more than twenty years prior... A small nitpick, but January 2005 is 19 years after 1986, not more than twenty. A very tiny nitpick in a great post.
4) On the M22 disaster, Part B: This has more than a whiff of the Challenger disaster. Intentional?
5) I cannot wait to see some cutaway renderings of the new habitat lander by Nixonshead.
6) If we are talking about multi-month long lunar surface stays, we now need to face the risks of big solar flares. We have far better capability to predict them in the 2000-2010 time frame than we did in 1968-73, but just the same, how does NASA plan to address this danger?
7) Speaking of mission-loss events...with this new look at reusable tugs, landers, and depots, is there any interest at putting in place some kind of genuine resuce capability at L2, or on standby at the Cape - a backup lander, say, in case the one on the surface is disabled? It made less sense with Apollo and Artemis, obviously, but with six month stays, let alone a permanent presence (with all the risks involved in systems sitting dormant on the lunar surface for so lengthy a period of time)?
8) Lastly, I am close to crying over how vast the difference in this reality - so plausible, yet so far away from what we actually DID - is from our timeline. The selenologists crying into their milk over being "shackled" to Shackleton really do not know how good they've got it. But such is the way of these things. Their only basis of expectations is what Artemis has been shoveling their way.
As a side note, however, the plausibility might come in for a question. The word "cheaply" appears in this post. While it wonderful to see NASA taking advantage of the private launch sector opening up to explore fuel depots and tugs, I do wonder if even the NASA of this timeline would place such a priority on cheaply, rather than just lobby for more money it likely won't get to do the same things more expensively - especially when it means more money for certain NASA contractors in certain states and districts. Perhaps, I fear, you are being slightly too optimistic after all. I realize that this is a harder question for a couple of engineers to answer adequately, however.
This is a great update - more food for thought than we have had in a while. Great work, gentlemen.
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Nice catch, that was supposed to be "just under...".
It owes some relationship to Challenger, yes, but it also is related to OTL Titan motor failures, such as the 1986 Titan 34D failure or the 1993 failure of a Titan IVA. It actually owes even more relationship to the latter--the failure mode (improperly repaired motor void) is drawn from that incident.
Beefed up storm shelter preparations, which can be handled a couple different ways, mostly using reconfigurable logistics storage or "water walls" (inflatable bladders that are filled with portions of the hab's water stocks when a flare is detected). NASA's got a few papers on the topic--I'm not qualified to say which specific approach is pursued, but there's definitely viable options within our mass budget.
Interest? Probably, but it's not really practical for Orion, at least.
For L2 storage, the hydrogen descent stage of the lander would require it to be kept at a depot, and topped at-need from that depot. This is potentially viable, but requires a depot to be placed there and fuel tankers to that infrastructure to be maintained--of interest for Oasis, but a serious ask for Orion (particularly as, despite TransOrbital's work on the topic, cryogenic propellant storage and transfer is still very much at TRL 6 or 7 in 205 when the system is being laid out--the Centaur depot demonstrator hasn't even flown!).
To retain a system at the Cape, instead, you run into infrastructure problems. The big problem here is that the Artemis ascent stage is 17 tons ready for launch from the lunar surface. In a single cargo lander launch, a portion of the Pegasus' propellant is spent merely achieving parking orbit, limiting how much propellant and cargo can be loaded into the descent stage--this is why the cargo and logistics landers are limited to 15.5 tons of touchdown mass.
You can fix that by using two H03s, one launching a fully-fueled Pegasus and the other launching the ascent stage/descent lander, and maybe a CSM (hey, the CSM could be the thing that broke, we can't know in advance!), but now you've essentially got to have two full two-launch Orion missions stacked and ready at the same time (the main crew, and the parallel potential rescue missions), and there's only three Mobile Launch Platforms and three fully-active VAB cells at the Cape. Standing up a fourth MLP and cell is a major cost increase for pretty low-odds cases--both the Apollo CSM and the ascent stage feature a lot of redundancy. The ascent stage, for instance, has three engines, and can lift off with any two, while the CSM is designed to loiter on-station at Freedom for six months. It's a lot of investment that can be better spent avoiding the situation in the first place, and thus again not really on the table for Orion. For Oasis, though, you could use a Pegasus tug/depot prepositioned in LEO, and thus both the initial crew launch to Orion and the rescue vehicle ready at the pad can be cut to a single launch each--making it feasible to maintain. As above, much more something for the future than achievable for Orion itself.
NASA's had a pretty bad record of lobbying for "just spend more money" both IOTL and ITTL--Artemis didn't take off and really start working until Ares and other aspects of Constellation were cut under Gore, and the project downscoped to fit what Congress was willing to actually pay, and the same was even more true when you're talking about budget-hawk President Woods. They've got allies enough to stop them from being cut too much, but seeing increases of several billions in NASA's budget don't seem likely--thus the drive to spend the same amount of money more efficiently and accomplish more. This is especially true when Thunderbolt is flying for roughly half the cost-per-kg of Saturn--the temptation to find a way to make use of that is strong, and would likely be investigated even if they thought they could also finangle more money. Since that's not really on the table...
Thank you! We put a lot of thought into this one, and I was initially sort of worried when it just drifted down without comment for the first day or so...
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I think,"cheaply," is relative. I also think it would act as a palliative for politicians. They can point at that, say,"See? Look at how we're minimizing expenses," and go back mostly to pork-barrel as usual with a "fiscal responsibility" get out of jail free card in their pocket. When it comes to a choice between frugality and Federal money in their district, fiscal responsibility will always get lip service.
While private sector launch services might save some money, the main goal will be to create a veneer of "responsibility." And the Republicans might find "private sector" has a nice ring to it vis a vis ideology.
While private sector launch services might save some money, the main goal will be to create a veneer of "responsibility." And the Republicans might find "private sector" has a nice ring to it vis a vis ideology.