Eyes Turned Skywards

[Athelstane]

e of pi,

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.

Thanks, this part actually answers my real question - I failed to make clear that I was really asking about Oasis, rather than this interim Orion arrangement. Obviously the predicates (depot, etc.) won't be in place yet.

We discussed rescue capability some time back, and you made it clear, reasonably, that it was hard to justify a rescue capability for short-term missions. Of course, once we're talking about a permanent presence on the surface, along with the rest of this infrastructure we're talking about, the equation starts to change, especially if you start talking reusable landers. The difficulty, of course, is that if a critical failure (some internal flaw, or a meteorite strike on ascent module or the CSM) is identified, the public won't understand why the astronauts are stranded and NASA can't rescue them...with Apollo 13 (or any Apollo mission failure), the astronauts would have been dead within hours, and the drama of impending death isn't stretched out over weeks, which has to be the ultimate NASA public relations disaster...

That said, if we are talking about a multi-month surface stay capability - and new Russian re-supply capability coming into being - you can now buy a lot of time for a rescue mission, just as NASA was able to have the time to assemble Skylab Rescue because of the life support available on Skylab.

Thanks for the clarification on solar flare shelters - don't know that I was expecting a detailed response, just that you had taken it into account and that there was the mass allowance and technology worked into the hardware.

I'm still going to nudge-nudge-wink-wink for renders on the new hab from Nixon, but that is only because I'm a greedy bastard. Please keep up the good work.

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...

Can't speak for others, but Easter weekend stuff left me AWOL for a few days.

 

[nixonshead]

I'm still going to nudge-nudge-wink-wink for renders on the new hab from Nixon, but that is only because I'm a greedy bastard. Please keep up the good work.

Ouch, my ribs! That may take a little while, but I'll add it to the list...

In the meantime, in a slight departure from my usual work, this week's image contains no 3D models at all, but is rather painted directly in GIMP.

 

[nixonshead]

Hmm, I'd like to see Longxing, Mir w/Tiangong <snip>

Well, here's the first couple!

 

[Athelstane]

Ouch, my ribs! That may take a little while, but I'll add it to the list...

No problem, Nixon. I can be patient.

 

[area11]

Well, here's the first couple!

I see that the Russian's didn't bother to replace the flags on Mir.

 

[e of pi]

I see that the Russian's didn't bother to replace the flags on Mir.

There's an easy enough excuse: they're painted onto the hull. You want to be out in an EVA suit with a spray can?

 

[nixonshead]

Whoops! I just noticed that's the old version of Longxing. The final model had a more conical reentry module. I'll update in the next couple of days. Sorry!

 

[Michel Van]

Here matching Art work for Copernicus mission

it originated from first version of 2001: A Space Time Odyssey.

 

[Kirk Kerman]

Love the new orthos nixonshead!

Anyways, I have a few assorted thoughts:

Would it be possible to use a Centaur or Pegasus stage on a Saturn M02 to replace the M22?

Would it be possible to introduce a "double core" configuration to replace M42 and M43?

And lastly, is there any way that the crew for Orion can use spent Descent Stages as anything other than lawn ornaments?

 

[e of pi]

Anyways, I have a few assorted thoughts:

And I have a few assorted answers!

Would it be possible to use a Centaur or Pegasus stage on a Saturn M02 to replace the M22?

Not enough liftoff thrust. T/W at ignition of an M02 scrapes 1.2, and going any lower starts stacking gravity losses on fast. Easiest way to boost liftoff thrust, of course, is...well, solids. Quite conveniently, the Saturn comes from the factory ready to fit some Titan ones...

Would it be possible to introduce a "double core" configuration to replace M42 and M43?

In theory, but the booster and core loads would require extensive and somewhat interesting re-analysis (not necessarily redesign, though that's possible too depending on details of how the loads are conveyed and balanced on Saturn that I don't even want to deal with, but re-analysis at least). Given there's been no call to launch an M42 or M43, unlike the M22, that's not really worth it.

And lastly, is there any way that the crew for Orion can use spent Descent Stages as anything other than lawn ornaments?

Maybe, but I'm not thinking of many off the top of my head. When the ascent stage lifts off, it takes with it a lot of the interesting bits. You've got some residual LH2/LOX in the tanks that you could pump out somehow and turn into water or leave as LOX to augment Orion's consumables, but with the tighter-loop ECLSS, it's the food that's the major limit on the number of missions that can visit the base, not water or air. Adapting the prop tanks to habitat space is kind of interesting, but the Artemis descent stage tanks aren't designed for ease of access--you'd almost need torches to cut them open, and even if you got in, you're tight on mass to outfit them--Orion's mass limited, not volume limited. You could grab spare batteries, maybe some really specific computer components, general wiring and hosing, but now you're starting to tear them to pieces. The familiar refrain around the Orion engineering bullpen: "They don't need it perfect, they need it in 2008. Maybe on Oasis..."

 

[Athelstane]

P.S. Not to get too far ahead of ourselves, but I think it's a plausible, even probable, eventuality that when Neil Armstrong dies in 2012, NASA renames the Orion International Lunar Outpost as the Armstrong International Lunar Outpost - if it's still up and running.

 

[Athelstane]

Not enough liftoff thrust. T/W at ignition of an M02 scrapes 1.2, and going any lower starts stacking gravity losses on fast. Easiest way to boost liftoff thrust, of course, is...well, solids. Quite conveniently, the Saturn comes from the factory ready to fit some Titan ones...

You're such a tease.

 

[Brainbin]

In the meantime, in a slight departure from my usual work, this week's image contains no 3D models at all, but is rather painted directly in GIMP.

Another gorgeous piece of artwork, nixonshead - but if I might ask, is that supposed to be Vandenberg Air Force Base, or a nearby settlement (say, Lompoc) in the background?

 

[nixonshead]

Another gorgeous piece of artwork, nixonshead - but if I might ask, is that supposed to be Vandenberg Air Force Base, or a nearby settlement (say, Lompoc) in the background?

It's not supposed to be Vandenberg, but rather nearby town. As to which one... The image was based on this photo, which was apparently taken from Big Bear, CA, which according to GoogleMaps is about 250 miles east of Vandenberg (though I must admit I failed to check the location before now). Obviously this is waaay too far to show the explosion in the level of detail in the illustration, so it must be from somewhere closer, but still up in the hills. Maybe the town is Santa Maria?

 

[brovane]

Not enough liftoff thrust. T/W at ignition of an M02 scrapes 1.2, and going any lower starts stacking gravity losses on fast. Easiest way to boost liftoff thrust, of course, is...well, solids. Quite conveniently, the Saturn comes from the factory ready to fit some Titan ones...

For the F1A engine on the Saturn M. Has there been any growth/changes in the engine over the almost 3 decades of service? Isn't this the same engine that flew on the Saturn-1C?

Just got me thinking if there was any room for further growth in engine power beyond 8 MN. Even a change in the engine design similar to the F1B proposal for the SLS Block II would take advantage of modern production methods to reduce parts which should reduce costs. The SpaceX Merlin engine in around a decade has gone from a 340 kN thrust engine to a 650 kN engine that is looks like now is going to have it's thrust increased again to 700+ kN.

 

[e of pi]

For the F1A engine on the Saturn M. Has there been any growth/changes in the engine over the almost 3 decades of service? Isn't this the same engine that flew on the Saturn-1C?

Just got me thinking if there was any room for further growth in engine power beyond 8 MN. Even a change in the engine design similar to the F1B proposal for the SLS Block II would take advantage of modern production methods to reduce parts which should reduce costs. The SpaceX Merlin engine in around a decade has gone from a 340 kN thrust engine to a 650 kN engine that is looks like now is going to have it's thrust increased again to 700+ kN.

As far as I know, the major increases in performance for Merlin have come for an ongoing ramp-up in chamber pressure, while the F-1A already starts out about where the Merlin 1D is. Thus, I'm inclined to say there's no major increases in chamber pressure, and no major growth in thrust or specific impulse. There are certainly ongoing modifications, the F-1A itself was developed as a cost reduction and I can see small tweaks continuing. The big change that would be a benefit there would be converting from a tube wall to a channel wall nozzle sometime in the 90s/00s, which would be a lot easier to build and thus cheaper (this would be the main difference between the F-1A of Eyes in 1990 and the F-1B proposal of OTL). OTOH, it'd pretty complex. I'm inclined to be vague about specifics of upgrades, particularly as they mostly are just nickle-and-dime cost improvements, not performance increases.

Not having to change the wiki performance figures and totally overhaul the mass figures behind the scenes for Artemis, Orion, and other things we're debating is nice, too.

 

[brovane]

As far as I know, the major increases in performance for Merlin have come for an ongoing ramp-up in chamber pressure, while the F-1A already starts out about where the Merlin 1D is.

Wasn't the F1A's planned chamber pressure around 1000 psi?

 

[e of pi]

Wasn't the F1A's planned chamber pressure around 1000 psi?

It's a challenge finding F-1A data, partially because the project was still in active development. It's one reason I'm not inclined to go trying to speculate of specific details of yet further performance improvements. This document has it at 1,161 psi chamber pressure (page 2), putting out 2,020 lbf (vac) at 304s (vac). Considering I've seen other citations for the F-1A at 310s, these must have had yet higher chamber pressure, which would be on par with the Merlin 1D's 1,400 psi.

 

[Michel Van]

It's a challenge finding F-1A data, partially because the project was still in active development. It's one reason I'm not inclined to go trying to speculate of specific details of yet further performance improvements. This document has it at 1,161 psi chamber pressure (page 2), putting out 2,020 lbf (vac) at 304s (vac). Considering I've seen other citations for the F-1A at 310s, these must have had yet higher chamber pressure, which would be on par with the Merlin 1D's 1,400 psi.

I Only found ONE original document on F-1A program on NTRS

F-1 Task Assignment Program Final Report by Rocketdyne, August 1974
R-8102
Contract NASA-18734

it mention thrust chamber inlet manifold & Jacket, range from 1222 psi minimum, 1716 psi static, 1901 psi maximum

 

[Athelstane]

Getting back to the "Soonbase"

...I'm thinking now about more ambitious radio telescopes, and wonder if NASA and the ESA are, too.

As we saw earlier, you had FROST dishes deployed by Artemis 7 and 8 missions to Mare Ingenii and the crater Antoniadi in 2002 and 2003 - that was the most they could reasonably squeeze into the cargo for two week Artemis missions. Now, however, with a permanent outpost, and resupply possible through Luna-Pe cargo landers (or even additional Orion-based landers), the possibilities would seem to open up for a deployment of a larger, more capable radio telescope at or near Shackleton - one which could be man-tended on a somewhat regular basis, and obviously located to be outside of radio pollution from Earth.

Do the authors have any thoughts on that? This might not be a top priority for the first few rotations at the outpost, but I'd be surprised if it doesn't end up on a manifest by the early 2010's. Indeed: radio telescopes won't be the only kind of telescopes that will be attractive for the outpost to deploy.