cozmicray - 23/6/2006 1:11 PM
Can someone point me to the trade studies or analysis that support the choice of a capsule design?
Seems NASA goes from airplane form to capsule form to airplane form to capsule form for no reason. The X planes to capsule to STS, dyna soar. CRV, VentureStar to now capsule CEV.
NASA can only have one at a time and NOT a truck to space and a mini to space. This way no progress is made. Are the lessons learned from Apollo being applied to CEV, are the lessons learned even captured or known. Don't take any risk, don't stretch/develop technology, never advance.
Just baffles me.
Tnx
HailColumbia - 23/6/2006 11:36 AM
I thought this debate had been long settled. (although I'm sure that Vt Hookie guy wouldn't agree)
The CEV is designed to return from the moon. It is going to hit the atmoshphere much faster then the shuttle does, the wings would snap off. Plus, they serve little purpose other then to land on a runway, they are deadweight that you would have to carry all the way to the moon, that means less useful payload. Dos the capsule look lame? yes, it definatly does, the space shuttle is probably the sexiest space ship we will ever see. "looking cool" is not a good enough reason to build a spacecraft into an aircraft. Now, if the CEV was only supposed to operate in LEO, then wings start to look good again.
I would hardly define wings as "progress" The starship enterprise had no wings, and THAT would be progress.
The "requirement" for uncontrolled abort is curious considering it doesn't exist today (within STS) and all systems have to be dual fault tolerant.Challenger proved the error in this strategy. Had there been a capsule/abort, the crew would still be with us.
zinfab - 23/6/2006 4:46 PMQuoteThe "requirement" for uncontrolled abort is curious considering it doesn't exist today (within STS) and all systems have to be dual fault tolerant.Challenger proved the error in this strategy. Had there been a capsule/abort, the crew would still be with us.
I liked the idea of a fly-off, where different ideas could be tested and compared.
astrobrian - 23/6/2006 9:28 PM Then why not go with unmanned "planes" and keep the capsules manned. sounds like the best of both worlds. We can fly UAVs all over the place, and run rovers all over mars, why not the shuttle. That would be able to keep the ISS partners happy and keep our astronauts safer in the process
What do you mean by unmanned planes? Cargo launch with spaceplanes? If so, then you're limiting the amount you can haul to space because a straight up expendable rocket will always be able to lift more than a cargo only spaceplane.
quark - 23/6/2006 7:44 PM
I am not defending STS or its level of safety. However, I think there needs to be a balance between a reasonable level of safety and a reasonable level of mission capability. To me, uncontrolled abort---in addition to "anytime abort", in addition to "dual fault tolerance", all above and beyond STS---tips the balance. No airplane or automobile meets an "uncontrolled abort" requirement. Maximum safety is not getting out of bed...
cozmicray - 24/6/2006 7:51 PM
The "Not invented here" permeates ALL NASA projects.
cozmicray - 24/6/2006 7:51 PM
All the lessons learned from Apollo have died with the old engineers.
zinfab - 23/6/2006 5:46 PMQuoteThe "requirement" for uncontrolled abort is curious considering it doesn't exist today (within STS) and all systems have to be dual fault tolerant.Challenger proved the error in this strategy. Had there been a capsule/abort, the crew would still be with us.
kraisee - 24/6/2006 4:15 PM
Oh and also the simple capsule will obciously be quicker to design and make than a more complex shaped craft - and reducing the time gap between Shuttle and CEV as much as possible is a critical requirement stipulated by Congress & the WHite House to NASA.
mlorrey - 24/6/2006 10:35 PMQuotezinfab - 23/6/2006 5:46 PMQuoteThe "requirement" for uncontrolled abort is curious considering it doesn't exist today (within STS) and all systems have to be dual fault tolerant.Challenger proved the error in this strategy. Had there been a capsule/abort, the crew would still be with us.
FIRST was proven to have uncontrolled abort capability (that was its purpose: as an inflatable winged space station escape and reentry pod). Wings or lifting bodies does not mean no uncontrolled abort capability.
And why is uncontrolled abort so important? With human pilots and autopilot controls, there is no event in which an uncontrolled abort is needed. Such capability would NOT have saved Challenger or Columbia.
Jim - 24/6/2006 10:16 PMQuotemlorrey - 24/6/2006 10:35 PMQuotezinfab - 23/6/2006 5:46 PMQuoteThe "requirement" for uncontrolled abort is curious considering it doesn't exist today (within STS) and all systems have to be dual fault tolerant.Challenger proved the error in this strategy. Had there been a capsule/abort, the crew would still be with us.
FIRST was proven to have uncontrolled abort capability (that was its purpose: as an inflatable winged space station escape and reentry pod). Wings or lifting bodies does not mean no uncontrolled abort capability.
And why is uncontrolled abort so important? With human pilots and autopilot controls, there is no event in which an uncontrolled abort is needed. Such capability would NOT have saved Challenger or Columbia.
FIRST maybe designed but not proven.
Uncontrolled is a requirement, for reentry (some ascent aborts have reentry). There have been uncontrolled entrys. One of the recent expeditions had one. The requirement is for power or control system failures, which have occurred
Jim - 25/6/2006 7:59 AM
They never did find the impact, correct?
cozmicray - 26/6/2006 12:13 PM
It will be neat to see the historians in 2080 trying to figure out "Why from STS to capsule"
No documentation at all, just a decision of the NASA admin at the time,
as the "Griffin Orbital Trash Collection System passes overhead.
nacnud - 23/6/2006 6:10 PMQuoteI liked the idea of a fly-off, where different ideas could be tested and compared.
Great idea, want to pay for it? It is very very hard to try and justify space planes over capsules on safety grounds. There might be operational advantages but a lifting capsule and a steerable parachute can land with pin point accuracy and RLVs have the flight rate problem.
quark - 26/6/2006 1:12 PMQuotenacnud - 23/6/2006 6:10 PMQuoteI liked the idea of a fly-off, where different ideas could be tested and compared.
Great idea, want to pay for it? It is very very hard to try and justify space planes over capsules on safety grounds. There might be operational advantages but a lifting capsule and a steerable parachute can land with pin point accuracy and RLVs have the flight rate problem.
The fly-off was exactly NASA's approach in the Steidle days. Probably would save money in the long run. It definitely would result in a better product. Today's approach is to select the CEV winner based on mountains of paper, and may the best liar win. Steidle's approach of a fly-off provided real data, both in term of design/technical performance and management/cost/schedule performance. More data = better decision. Next time you buy a car, don't bother to test drive, just look at the glossy brochures...
quark - 26/6/2006 4:12 PM
The fly-off was exactly NASA's approach in the Steidle days. Probably would save money in the long run. It definitely would result in a better product. Today's approach is to select the CEV winner based on mountains of paper, and may the best liar win. Steidle's approach of a fly-off provided real data, both in term of design/technical performance and management/cost/schedule performance. More data = better decision. Next time you buy a car, don't bother to test drive, just look at the glossy brochures...
Jim - 26/6/2006 7:39 PM
The flyoff was not going to use full up complete spacecraft. They were going to be boilplate model, with only the outmold line, weight and CG modeled. The flights would have been only abort or reentry tests. They were scheduled for 08, which left little time for complete development.
HailColumbia - 26/6/2006 7:09 PMQuoteJim - 26/6/2006 7:39 PM
The flyoff was not going to use full up complete spacecraft. They were going to be boilplate model, with only the outmold line, weight and CG modeled. The flights would have been only abort or reentry tests. They were scheduled for 08, which left little time for complete development.
And now that NASA has dictated the outermold line, seems like a flyoff would be useless under these condiditons
quark - 27/6/2006 1:57 AMQuoteHailColumbia - 26/6/2006 7:09 PMQuoteJim - 26/6/2006 7:39 PM
The flyoff was not going to use full up complete spacecraft. They were going to be boilplate model, with only the outmold line, weight and CG modeled. The flights would have been only abort or reentry tests. They were scheduled for 08, which left little time for complete development.
And now that NASA has dictated the outermold line, seems like a flyoff would be useless under these condiditons
Exactly! Once NASA dictates the solution, all opportunity for innovation by the contractor teams goes out the window. At that point, all we're left with is politics and jobs programs. Depressing...
Jim - 27/6/2006 6:01 AM
It was done to save money and time. Testing and qualification was reduced. It was a smart move. The same thing was done for Apollo and Mercury. Saturn V was done the same way.
There is nothing wrong with this type of contracting. They weren't looking for advancing the state of the art.
spfrss - 27/6/2006 11:26 AM
So, welcome back capsules and focus on exploration instead of technology development
nacnud - 27/6/2006 2:16 PM
Well wich is more useful, lots of small sailing ships or the Great Easton stuck on the bank of the Thames?
nacnud - 27/6/2006 5:37 PM
God my spelling sucks, sorry about that.
The Great Eastern, thats the one. It's always hard to draw anaolgies that hold but your description of it does sound a little like everyones favorite space plane, the Shuttle.
bad_astra - 29/6/2006 3:05 PM
Thats's a poor choice of words at the end of your post, IMHO. I agree work should be done on TPS. I don't care if it's a capsule or not, as long as it does the job. For a Lunar program, the Apollo CM shape will be just fine. It was before.
OTOH, if I thought the CEV, Shenzhou, and Soyuz would be all the manned orbital access we'd see for the next few decades, I'd be fairly depressed about that.
bad_astra - 29/6/2006 4:05 PM
OTOH, if I thought the CEV, Shenzhou, and Soyuz would be all the manned orbital access we'd see for the next few decades, I'd be fairly depressed about that.
Jim - 30/6/2006 2:03 PM
Just remember CEV is not just for LEO, it is for lunar and Mars Return
vt_hokie - 1/7/2006 4:20 PMQuotebad_astra - 29/6/2006 4:05 PM
OTOH, if I thought the CEV, Shenzhou, and Soyuz would be all the manned orbital access we'd see for the next few decades, I'd be fairly depressed about that.
They might be, sadly. Although, if SpaceDev claims it can develop the orbital version of its HL-20 derived "Dreamchaser" for ~$100 million, I say give them the money rather than giving billions of taxpayer dollars to ATK and other contractors to support their porkbarrel Apollo-era capsule design and antiquated shuttle derived launch vehicles.
vt_hokie - 1/7/2006 4:23 PMQuoteJim - 30/6/2006 2:03 PM Just remember CEV is not just for LEO, it is for lunar and Mars ReturnI don't buy the Mars claim, and when humans finally do go to Mars, I doubt the CEV capsule will have anything to do with it. As for returning to the moon, I have yet to hear a compelling reason for doing so, especially given the high costs and low flight rates that the ESAS hardware will result in. Before we can do any meaningful exploration on a significant scale, we need a better, more cost effective means of reaching orbit.
My understanding on it is that there's no way to brake into Earth orbit on a Mars return... or even a lunar return for that matter. It's not that it's impossible, the propellant needed for the deltaV is prohibitively high. You'd have to carry it all they way to the destination and back. Now the only way you can do a direct entry from those speeds coming back from Mars or the moon is with a blunt body capsule. If you can find a way to do EOI from Mars or the moon than, I think, the major advantage of capsules goes away.
hyper_snyper - 1/7/2006 3:46 PMQuotevt_hokie - 1/7/2006 4:23 PMQuoteJim - 30/6/2006 2:03 PM Just remember CEV is not just for LEO, it is for lunar and Mars ReturnI don't buy the Mars claim, and when humans finally do go to Mars, I doubt the CEV capsule will have anything to do with it. As for returning to the moon, I have yet to hear a compelling reason for doing so, especially given the high costs and low flight rates that the ESAS hardware will result in. Before we can do any meaningful exploration on a significant scale, we need a better, more cost effective means of reaching orbit.My understanding on it is that there's no way to brake into Earth orbit on a Mars return... or even a lunar return for that matter. It's not that it's impossible, the propellant needed for the deltaV is prohibitively high. You'd have to carry it all they way to the destination and back. Now the only way you can do a direct entry from those speeds coming back from Mars or the moon is with a blunt body capsule. If you can find a way to do EOI from Mars or the moon than, I think, the major advantage of capsules goes away.
mlorrey - 1/7/2006 7:54 PM
Doing a direct entry with a blunt body capsule would experience MUCH higher G forces than a lifting body. That is the whole point of using the lifting body: the g forces are much more moderate. In fact, the only way to make a capsule do a direct entry in a way that is tolerable for most astronauts would be a very oblique entry that used at least one skip to bleed energy. A single augering in would impose G loads of 10 gs or more.
vt_hokie - 1/7/2006 8:08 PMQuotemlorrey - 1/7/2006 7:54 PM
Doing a direct entry with a blunt body capsule would experience MUCH higher G forces than a lifting body. That is the whole point of using the lifting body: the g forces are much more moderate. In fact, the only way to make a capsule do a direct entry in a way that is tolerable for most astronauts would be a very oblique entry that used at least one skip to bleed energy. A single augering in would impose G loads of 10 gs or more.
Which is why Lockheed Martin originally proposed this design (http://www.popularmechanics.com/science/space/1534782.html) for the CEV.
shuttle_buff - 1/7/2006 10:50 PM
Hyper-X is just not ready today (and it would serve LEO missions only anyway)
The Apollo-style space ship is a stop-gap to get us through 2025.
The next generation space ship will be the Hyper-X.
What do others think?
Shuttle_buff
cozmicray - 23/6/2006 10:11 AM
Can someone point me to the trade studies or analysis that support the choice of a capsule design?
...
mlorrey - 1/7/2006 4:54 PM
...Doing a direct entry with a blunt body capsule would experience MUCH higher G forces than a lifting body. That is the whole point of using the lifting body: the g forces are much more moderate. In fact, the only way to make a capsule do a direct entry in a way that is tolerable for most astronauts would be a very oblique entry that used at least one skip to bleed energy. A single augering in would impose G loads of 10 gs or more.
Jim - 30/6/2006 11:03 AM
... Just remember CEV is not just for LEO, it is for lunar and Mars Return
MATTBLAK - 2/7/2006 5:58 AM
In a little fit of irritation, and with nothing personal meant I have to ask you AGAIN hokie: What IS it with you and spaceplanes?? You're flogging an (unfortunately) very dead horse. I know it's human nature to sometimes not let something go, but really....
I and others have TOLD you that private spaceplanes are on the way and that Shuttle is going the way of Concorde -- fragile, expensive to operate and (allegedly) far too expensive to replace with something "better". Better for trips to LEO, that is.
And have you noticed: the Klipper lifting body/spaceplane design has been dropped, dropped DROPPED. It's going to be (drumroll)... a CAPSULE-derivation!! Didn't I tell you months ago that might happen? (sadly).
Throw your support behind Virgin Galactic and Rutan's Scaled composites. They look to be virtually the only show in town now. Otherwise, this is the only kind of spaceplane you're going to see anywhere anytime soon:
zinfab - 2/7/2006 2:45 PM
So the method is MORE important than the mission, VT?
I know you're a spaceplane fan, but PLEASE stop whipping NASA for being "too afraid" to use the ONE SHAPE you happen to prefer. Sending humans to the moon is MUCH bolder than floating in LEO.
Given that it will take both a CLV launch and an ARES/HLV launch for each flight, it'll probably cost as much or more per mission than the space shuttle does!
bad_astra - 2/7/2006 4:02 PM
In fairness, even if it costs that much (which I doubt), It will be doing something far more interesting then station reboost.
MATTBLAK - 2/7/2006 3:30 PM
Your analogy about the Northrop/Flying wing is a good one!!
vt_hokie - 2/7/2006 3:28 PMQuotebad_astra - 2/7/2006 4:02 PM
In fairness, even if it costs that much (which I doubt), It will be doing something far more interesting then station reboost.
See, to me walking around on the moon isn't much more interesting than ISS missions. But to each his own...
Now, if humans were to really leave Earth orbit and travel to Mars, that would be interesting!
vt_hokie - 2/7/2006 12:21 PM
I dunno...just can't get excited about capsules, or let go of my desire for a next generation reusable space plane. You're right, I guess it's human nature. Seriously, though, the Apollo-derived capsule design seems like a significant step backward to me for numerous reasons.