Why 3 seats? even OTL there was a 5seat version (which never flew).
http://www.astronautix.com/craft/apouecsm.htm
Rescue Skylab would have involved flying with 5 crew only for the descent from the station, thus a very short period would have been spent with 5 people onboard the craft--just the period to undock, pull away, and de-orbit--an hour or three at most. For an entire mission, launch to docking and undock to landing, this wouldn't have been acceptable. So while there's room in the CM for 5, there'd need to be additional volume to actually fly with 5 routinely. Now, admittedly, they do have several tons of margin on the Saturn 1C, so...well, let's see, shall we?
Perhaps, but IOTL, the servicing of the Hubble was a bit of a red herring. For the cost of the servicing missions, they could have built (and launched) at least one more, since the cost of Shuttle missions was so incredibly high.
Yes. It worked fine, like every attempted use of heat-shield hatches that I know of. It's probably exactly *because* such hatches are so apparently dangerous that they've been so safe, since the engineers feel the need to triple-check everything to make sure it works perfectly.
I'd have thought more people would be fascinated by what O'Neill was up to, though, considering his influence IOTL.
The thing about O'Neill is, you have to believe he's right about the economics--that human beings will find reason to move massively into space like that. As an SF fan and someone who grew up around high tech stuff (Air Force brat here) I just casually assumed we'd be doing it.
The critical thing is reasonably inexpensive access to orbit. That's why I was going on about dynamic loops etc.
Something I've been amusing myself with for the past few weeks is trying to work out the basic physics of suborbital flight, in the sense of having regularly scheduled ballistic passenger transport (obviously for intercontinental distances.)
I humbly submit, if one can have transport to orbit economical enough to begin to bootstrap a project on the scale O'Neill was pushing, one can have very expensive (but affordable to the very rich, in the sense that Concorde flights were affordable) suborbital flights. And vice versa, if you are looking for projects with a payoff that would justify development of any given orbital system--be it rockets achieving economics through large scale and volume of use, or something with a big up-front cost like the dynamic loops--then having suborbital passenger service for Earth would be an important part of achieving that volume.
I am very skeptical rockets can do the job. I hasten to add, I'm not accusing your timeline of suggesting they could, I realize you aren't proposing commercial ballistic flights! What your timeline seems to be headed for is for NASA, or some other big and publicly funded concerns, or conceivably some niche businesses that operate in orbit and beyond, but not the sort of grand scale of human migration into space O'Neill was promoting.
So I'm not saying there is anything wrong with your rockets. But I don't think O'Neill's vision could be realized without the sorts of tech I felt rather discouraged from mentioning.
Then there are the hard-nosed questions of what exactly space colonists would do for a living, to justify the large investment in putting them up there. The solar-power-from-orbit vision seemed very clear to a starstruck kid in the 1970s but now I have to ask, for the total investment necessary to provide a given flow of gigawatts or terawatts from orbit, could we not instead manufacture so many solar power stations to deploy here on Earth that despite all the drawbacks of Earth-based sun power here at the bottom of the atmosphere, we'd still get more, maybe far more, generating capacity that way?
Obviously it's a Catch-22; until we already have at least large space stations crewed with at least dozens of researchers continually, the chances are low we'd think of something that can only be done in space--with the powerful sunlight, the near-perfect vacuum, the microgravity--that is worth shipping raw materials up, or sending miners with all their elaborate life-support needs out into the asteroids to obtain to satisfy some market here on Earth to pay for the investment, when of course we are hitherto hobbling along without whatever it is that will someday perhaps make some early investors in space rich. Once one such thing is discovered and large permanent space facilities are developed, I'd think soon there would be more things of that kind and soon life without human industry in space would become unthinkable. There'd then be more infrastructure there, each aspect of which creates both new needs and new opportunities.
But first there has to be that investment in trying stuff out on the off chance something will prove valuable. Obviously we've already gotten used to getting a lot of uses out of space, but hitherto nothing seems to require human presence there to reap the benefits, and it's much easier and safer to launch automated systems--which can simply be written off if a launch fails or the satellite malfunctions, and which have much less demanding support requirements. Sending astronauts up to fix equipment in space is, given the tremendous costs of a launch (and risks) much less sensible than simply trying again with another satellite launch.
So inspirational as O'Neill was to my young self, I'd worry that he'd merely as it were ground the lightning that otherwise might lead to the potentials of human aspiration pushing for some kind of activity in space. If it weren't for O'Neill, some other visionary would point the way to grandiose space enterprises of course. Then the cost-counters will again ask whether the large investments necessary to bring the cost of each necessary kilogram launched into orbit (reduced both by higher volumes of launch leading to reduced prices per, and by leveraging space resources and superior opportunities for reuse of materials when operating on a larger scale to lower the ratio of mass actually used to mass that needs to be launched) will lead to any foreseeable returns. They will point to the romantic vision that quite admittedly is part of the background of pro-space sentiment as insufficient and unworthy and defer all consideration to future generations. Who will tend to do the same. A mass movement of people interested in seeing action in space but without the out of pocket means of paying for it on their own personal initiative will not only be discounted but cited as a reason for more "hardheaded" people to discount perfectly feasible space investments.
Then of course meanwhile the military will be involved; clearly they help in many ways, but they also muddy up the waters with their metaphors of "seizing the high ground" and their institutional interest in showing how war can be waged from above-and therefore should be, their logic implies--if we don't do it someone else will do it to us. But if in fact space activity can be slowed to a trickle merely by not funding it, all sorts of problematic possibilities the generals and their enthusiastic subordinates and their contractors are so keen to lay out in glowing detail before Congress and the press can be deferred, along with the alternative of developing some kind of international order in space that can be relied upon to deliver peaceful benefits without giving some armed camp or other extra leverage in their space-war schemes. All of that is moot if the presence of even the most active spacefaring nations is a matter of some fleets of unmanned satellites and a handful of small temporary space stations.
So at the end of the day, O'Neill's schemes are interesting, but I don't see how they lead anywhere good they didn't OTL. Unless they mean that some mode of launch that is much cheaper than anything OTL is developed. Which they hardly did OTL, so it remains to be seen why it would work so much better ITTL.
I was very interested to see O'Neil's vision laid out here but it didn't seem like the specifics mattered all that much. While this metaphor doesn't entirely work, I assumed his final vision was being treated as something like the western route to the Indies: the goal that drives us whether it's possible or not.
I suppose it would be interesting to speculate what sort of technological advantages we'd gain from attempts to realize this vision, but I'm still on first-level, un-nuanced guesses like advances in solar power and the mass driver.
I suppose it would be interesting to speculate what sort of technological advantages we'd gain from attempts to realize this vision, but I'm still on first-level, un-nuanced guesses like advances in solar power and the mass driver.
This is a pretty good metaphor, actually. For a real example of this happening with OTL space advocacy groups, part of the reason Musk got interested in launch vehicles was that his attempts to help bankroll a Mars Gravity Biosatellite in 2001 as a tech demo for the Mars society couldn't find an LV for a "reasonable" cost. And thus, he founded SpaceX. I'm not sure yet if O'Neill's visions get more traction in Eyes Turned Skyward, but his group is poised to serve a role in driving innovation in the low-cost spaceflight field.
Post 16: ELVRP I (Expendable Launch Vehicle Replacement Program) and the Delta 4000
Hello all! Sorry about the delay in this post getting up, real life has been eating my lunch the last few days. Anyway, this week in ETS we're jumping back a bit to the mid-70s and taking a look at the military space.
Eyes Turned Skyward, Post #16:
For the military, the space launch systems of the mid-1970s were anything but adequate. The Air Force, the Navy, and especially the National Reconnaissance Office (popularly known as the NRO, although its existence was top-secret at the time) were launching increasingly large and heavy satellites to perform a wide variety of missions in space, from communications to meteorology to perhaps the most important of all, spying. Spy satellites in particular were monsters, with the latest KH-9 weighing over 25,000 pounds (11,000 kg), severely taxing the largest launch vehicles the Air Force had available. Further, they had been growing rapidly in weight over the last decade, with the KH-9 weighing over 4 times as much as its predecessor, and even where they weren't all that heavy themselves it was obvious that existing launch vehicles were inadequate, as with signals intelligence satellites and their high orbits that demanded large launch vehicles to place their upper stages into orbit. Further increases in capacity would be needed for the planned GPS network that would allow American forces to easily pinpoint their location anywhere on the planet, but which demanded a huge number of satellites in medium orbits to function. It was clear that the existing hodgepodge of "legacy" ICBM-derived launch vehicles was not really capable of servicing the payloads envisioned for the 1980s and beyond. So it was that the ELVRP, or "Expendable Launch Vehicle Replacement Program" was begun in 1975.
From the start, it was revolutionary in outlook. The goal was to deliver a cheaper, more reliable, more easily serviceable booster using existing technology that was designed--from the ground up--to serve as a launch vehicle, replacing most boosters then in use by the US military with a single family capable of servicing most planned payloads. All previous US launch vehicles, aside from the expensive and NASA-exclusive Saturns and the extremely limited Scouts, had been derived from ballistic missiles, whether directly (in the case of the Atlas or Titan II) or indirectly (as with the Titan III or Vanguard). Indeed, most launch vehicles worldwide, from Soviet launchers such as the Proton and even the N-1 to the Europa design developed by the European Launcher Development Organisation, had at least some missile heritage. The ELVRP constituted nothing less than the first steps towards modern launcher designs and modern launch management.
The first vehicle contracted under the ELVRP was intended to replace the Titan III variants and other rocket in similar payload ranges. The DoD demanded a capability of no less than 13,000 lbs, ideally with some ability to tailor vehicle capability to specific mission requirements. Competition for the contract was fierce, with most aerospace companies currently involved in astronautics submitting at least some proposal. After all, the whole point of the ELVRP was to cut down the numbers of rocket designs in service, meaning a failure to get in the game could be a death knell. Convair submitted the Atlas 1, a largely re-engineered Atlas variant. Martin submitted a variant on the Titan, while McDonald Douglass submitted the Delta 4000. Even Boeing, busy with the new redesigned first stage for the Saturn 1C, put in a proposal, the largely-clean-sheet Neptune, though it was essentially understood to be dead-on-arrival.
Very quickly, the competition was reduced to the Titan IV and Delta 4000 proposals. While the DoD was interested in a new design, they also did not want to risk their entire space launch capability on totally untried components. Titan IV and Delta 4000 shared many features: both were based extensively on existing vehicles, both would use a liquid core boosted by a variable number of solid rocket engines, and both were intended for use with the venerable Centaur upper stage. However, Titan’s core stage still used toxic hypergolic fuels, while the Delta 4000 used the less toxic and more easily handled kerosene/LOX fuels. Furthermore, the Delta design had incorporated flexible solid booster configurations for years, and the McDonnell Douglas team was able to present designs for an entire family of boosters capable of scaling across almost all of the Air Force’s medium-lift needs, including detailed cost, development time, and performance estimates. By contrast, the Martin team seemed ill-equipped to handle the variety of missions their proposed booster would launch, and often seemed lost in presentations. The Delta 4000 quickly became the leading contender, and after its selection, work began with a first flight tentatively scheduled for 1980.
Eyes Turned Skyward, Post #16:
For the military, the space launch systems of the mid-1970s were anything but adequate. The Air Force, the Navy, and especially the National Reconnaissance Office (popularly known as the NRO, although its existence was top-secret at the time) were launching increasingly large and heavy satellites to perform a wide variety of missions in space, from communications to meteorology to perhaps the most important of all, spying. Spy satellites in particular were monsters, with the latest KH-9 weighing over 25,000 pounds (11,000 kg), severely taxing the largest launch vehicles the Air Force had available. Further, they had been growing rapidly in weight over the last decade, with the KH-9 weighing over 4 times as much as its predecessor, and even where they weren't all that heavy themselves it was obvious that existing launch vehicles were inadequate, as with signals intelligence satellites and their high orbits that demanded large launch vehicles to place their upper stages into orbit. Further increases in capacity would be needed for the planned GPS network that would allow American forces to easily pinpoint their location anywhere on the planet, but which demanded a huge number of satellites in medium orbits to function. It was clear that the existing hodgepodge of "legacy" ICBM-derived launch vehicles was not really capable of servicing the payloads envisioned for the 1980s and beyond. So it was that the ELVRP, or "Expendable Launch Vehicle Replacement Program" was begun in 1975.
From the start, it was revolutionary in outlook. The goal was to deliver a cheaper, more reliable, more easily serviceable booster using existing technology that was designed--from the ground up--to serve as a launch vehicle, replacing most boosters then in use by the US military with a single family capable of servicing most planned payloads. All previous US launch vehicles, aside from the expensive and NASA-exclusive Saturns and the extremely limited Scouts, had been derived from ballistic missiles, whether directly (in the case of the Atlas or Titan II) or indirectly (as with the Titan III or Vanguard). Indeed, most launch vehicles worldwide, from Soviet launchers such as the Proton and even the N-1 to the Europa design developed by the European Launcher Development Organisation, had at least some missile heritage. The ELVRP constituted nothing less than the first steps towards modern launcher designs and modern launch management.
The first vehicle contracted under the ELVRP was intended to replace the Titan III variants and other rocket in similar payload ranges. The DoD demanded a capability of no less than 13,000 lbs, ideally with some ability to tailor vehicle capability to specific mission requirements. Competition for the contract was fierce, with most aerospace companies currently involved in astronautics submitting at least some proposal. After all, the whole point of the ELVRP was to cut down the numbers of rocket designs in service, meaning a failure to get in the game could be a death knell. Convair submitted the Atlas 1, a largely re-engineered Atlas variant. Martin submitted a variant on the Titan, while McDonald Douglass submitted the Delta 4000. Even Boeing, busy with the new redesigned first stage for the Saturn 1C, put in a proposal, the largely-clean-sheet Neptune, though it was essentially understood to be dead-on-arrival.
Very quickly, the competition was reduced to the Titan IV and Delta 4000 proposals. While the DoD was interested in a new design, they also did not want to risk their entire space launch capability on totally untried components. Titan IV and Delta 4000 shared many features: both were based extensively on existing vehicles, both would use a liquid core boosted by a variable number of solid rocket engines, and both were intended for use with the venerable Centaur upper stage. However, Titan’s core stage still used toxic hypergolic fuels, while the Delta 4000 used the less toxic and more easily handled kerosene/LOX fuels. Furthermore, the Delta design had incorporated flexible solid booster configurations for years, and the McDonnell Douglas team was able to present designs for an entire family of boosters capable of scaling across almost all of the Air Force’s medium-lift needs, including detailed cost, development time, and performance estimates. By contrast, the Martin team seemed ill-equipped to handle the variety of missions their proposed booster would launch, and often seemed lost in presentations. The Delta 4000 quickly became the leading contender, and after its selection, work began with a first flight tentatively scheduled for 1980.
Delta 4000 Series for USAF? Why does it sound a lot like the Delta 2 Series of ELVs? IIRC, the Delta 2 used a LOX/Kerosene 1st stage with a hypergolic upper stage, with 0, 3, 6, or 9 SRBs. How many similarities does the Delta 4000 hold with the Delta 2? I'm willing to guess that similarities in flexibility will be the main point of similarity between OTL Delta 2 and TTL Delta 4000.
As for the Titan IV. I recall that the early Titan IVs OTL not only suffered severe reliability issues, but was also sometimes more expensive than STS due to the manner in which it had been uprated from the Titan II/III.
In any case. I have my suspicions as to why they had a preference for LOX/Kerosene powered LVs, with a little public relations boost on the side - since it won't really see use as a missile. Mainly that they had more than a number of fatalities from exploding missiles in Silos, and not just from being burned alive!
As for the Titan IV. I recall that the early Titan IVs OTL not only suffered severe reliability issues, but was also sometimes more expensive than STS due to the manner in which it had been uprated from the Titan II/III.
In any case. I have my suspicions as to why they had a preference for LOX/Kerosene powered LVs, with a little public relations boost on the side - since it won't really see use as a missile. Mainly that they had more than a number of fatalities from exploding missiles in Silos, and not just from being burned alive!
Why? Well, for one thing the Delta II was very much like the earlier Deltas (once McDonnell Douglas had moved to the x000 numbering system). If you compare to the Delta 3000 (OTL 1975-1989), for instance, they look almost identical externally (they're obviously different internally). McDonnell Douglas had a very good thing going with the Deltas, why would they change that up? And the Deltas were solid rockets, even if a bit prone to producing space debris. More to the point, the general use profile is similar, only moved back since there's no space shuttle or push to put everything on the Shuttle.
I would be willing to be the Delta 4000 is quite similar to the Delta II, although differing in many details due to being developed earlier. It has the same basic Thor heritage and the same GEM SRMs. The big difference is that the engines will be different, and the upper stage is hydrolox (probably a single-engine Centaur, but e of pi is your man for those details) rather than the OTL hypergolics.
This Titan IV has very little in common with the OTL Titan IV. Think the Delta IV or Atlas V in comparison to the early Atlases and Deltas.
Well, there is the BFRC problem in a failure, true. But hypergolics are also getting really expensive as environmental regulations get tighter, and they're pains to store and handle (solids are also pains, but mostly in the post-launch phase). Any brain-dead idiot could store kerosense safely, and LOX is not that much more dangerous. Both are also a lot cheaper.
More like a Delta 3, then, eh? Not sure why that one was so problem-prone, it should have been a good rocket and natural extension of the old Deltas.
Still, I'm not sure how you get shuttle/Titan4 sized payload lifted on any direct descendant of the Deltas...
We didn't say the Deltas were lifting that size of payloads, now, did we?
Just wait and see...
Doesn't the above quote imply your Deltas can lift as much as a Titan 4, in max configuration?We didn't say the Deltas were lifting that size of payloads, now, did we?
Remember, this Titan IV is not our Titan IV--the connection between it and the OTL Titan IV is about as strong as between the OTL Delta IV and the OTL Delta II. The particularly relevant line is:
Now, technically the OTL Titan IV fit this...since it had a payload of ~40,000 lbs...but it is obviously a bit fat for the job. The moniker is just Martin Marietta's marketing getting the way, trying to sell a whole new rocket to the Air Force.
You'll see what the real counterpart to the Titan IV is soon enough.
Truth, thanks for covering the fort while I've been hip deep in finals. After I get some sleep tonight, I'm going to take a crack at addressing some of these technical questions.
Indeed. For those looking for tidbits, you might want to review the intro post, there's some clues hidden in there.
Aha! Yes, I had seen the comments about this T4 being as related to previous Titans and the current Atlas and Delta rockets are to theirs. What I THOUGHT I had remembered was a line about the Titan 3 not having enough lift, which seems to be a mis-remembering on my part. So I was expecting at least that lift (13 tonnes to low orbit).
One also doesn't expect generation n of a rocket to lift less than generation (n-1), so that fed into my expectations of the *T4, too.
Thank you for being patient, as it was not at all clear to you what MY misunderstanding was.
You're not misremembering: We just haven't gotten to the part where they actually look into breaking their Titan III limits, yet. You'll see...
You're not misremembering: We just haven't gotten to the part where they actually look into breaking their Titan III limits, yet. You'll see...
That will be interesting to see. Wonder how they plan to handle the 14,000Kg+ payloads they might have in the future.