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#40
by
Jim
on 14 May, 2006 20:02
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vt_hokie - 14/5/2006 3:37 PM
Jim - 14/5/2006 2:08 PM
The real reason that RLV won't work in the near, it because LEO is not where the money is made. It is at GEO and most ELV's optimized to deliver spacecraft to GTO. RLV can not used for this orbit because dropping off a spacecraft with an upperstage at LEO is inefficent.
Why does it have to be about making money? How about getting more for our dollar out of NASA, which is not a profit driven enterprise. What if, instead of getting 4 flights per year at best out of STS, we spent the same amount on a system that gave us 20 or more flights per year?
Other than ISS, NASA doesn't need to get to LEO, it needs to go further. It is about making $, because usually the more inexpensive processes are the more profitable. NASA doesn't need 20 flights a year to LEO. It needs to go further. NASA has been stuck in LEO. Let commercial companies find the better way.
How about this for a scenario.
A RLV is used to fly components of the ESAS to LEO, which may be the cheapest way. But to get the men to it, a system similar to CEV and CLV is used.
That would be more likely to occur.
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#41
by
vt_hokie
on 14 May, 2006 20:15
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Jim - 14/5/2006 3:49 PM
Other than ISS, NASA doesn't need to get to LEO, it needs to go further.
Again, why? What is the need to go further? Let's be honest, we don't have the technical capability to go beyond the moon right now, and it will take better radiation protection, more advanced propulsion, and more reliable, self sustaining craft before we do. So, it's a choice between LEO and the moon right now. What's so much more pressing about getting to the moon than LEO? Seems to me we could do more in low Earth orbit with ISS utilization than we can do on the lunar surface given present technological and economic limitations.
NASA has been stuck in LEO.
Mainly because there has been no compelling reason to return to the moon. Do I want to see humans go back? Yes, but I always figured the next humans to travel to the moon would be flying on something more advanced and capable than the CEV, while dozens more humans lived and worked in LEO.
How about this for a scenario.
A RLV is used to fly components of the ESAS to LEO, which may be the cheapest way. But to get the men to it, a system similar to CEV and CLV is used.
That would be more likely to occur.
The way I always pictured it, a vehicle like NASP or VentureStar would transport crews to LEO, where they would enter an Earth departure vehicle that was assembled on-orbit. I actually agree with the concept of the "SDHLV", and I think we should have both a reusable space plane and a heavy lift cargo vehicle. But it's a shame that NASA will have to spend billions to replicate the heavy lift capability that Russia had 20 years ago with Energia.
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#42
by
imfan
on 14 May, 2006 20:48
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vt_hokie - 14/5/2006 3:02 PM
But it's a shame that NASA will have to spend billions to replicate the heavy lift capability that Russia had 20 years ago with Energia.
I agree. I have read somewhere that there was possibility to get licence to build energias in US. that would be great. but politicaly unrealistic
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#43
by
Jim
on 14 May, 2006 20:58
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vt_hokie - 14/5/2006 4:02 PM
but I always figured the next humans to travel to the moon would be flying on something more advanced and capable than the CEV, while dozens more humans lived and worked in LEO.
Define "more advanced" Wings does not equate to more advanced. You are getting hung up on aerodynamics. The inside is going be more advance.
Not everything that is forcasted becomes reality. Nuclear powered aircraft, gas turbine cars, Hi speed cars, personal aircraft, LEO comsats, etc
ISS experiments are a farse. There is nothing new under the sun. The same experiments that flew on the Spacelab missions and on the Spacehab module are still flying on the ISS. What disappointed me the most while working on all the Spacehab missions was that we flew the same experiments over and over. There wasn't much difference in the experiments on the first to the last mission. And I then I saw that most of them are still flying on ISS.
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#44
by
vt_hokie
on 14 May, 2006 21:11
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Jim - 14/5/2006 4:45 PM
Not everything that is forcasted becomes reality. Nuclear powered aircraft...
Well, that's a disaster waiting to happen! Some ideas are just bad.
gas turbine cars
Why was that ever a proposal? So that we could get the fuel mileage of an Abrams tank?
Hi speed cars
Too dangerous, but high speed trains work quite well!
personal aircraft
See the last example.
ISS experiments are a farse. There is nothing new under the sun. The same experiments that flew on the Spacelab missions and on the Spacehab module are still flying on the ISS.
That may be true now, but what if we completed ISS, including the now cancelled centrifuge and everything else?
Personally, I just don't find CEV to be very exciting or inspiring. It is what it is, and it seems that this is the future of NASA whether I like it or not. But I don't think I'll ever be as enthusiastic about our space program again because of it.
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#45
by
mong'
on 14 May, 2006 21:31
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I will have to join jim on that: NASA needs to go further.
There is nothing to do in LEO, nothing to explore, nothing to exploit, nothing to settle.
The best you can do in orbit is some basic science and maybe have a small scale factory for very special (thus expensive) goods.
Compare that to the surface of a planet (or a moon for that matter). you can use the available resources to produce supplies, oxygen, fuel for rockets and rovers, metals to upgrade your base and ultimately start to settle the entire planet. opening a whole new world in the process
Access to orbit is only a step, not a goal. the planets are the goal, when we talk about exploration of space it's really exploration of the planets. and only when we will have (semi) permanent manned outposts, bases, colonies (whatever you call it) THEN we will have a real need for the kind of RLV you talk about, but for now the ELV's do the job and they're good at it, the only improvement we might see right now is the development of cheaper ELV's ala Falcon1.
so vt_hokie you might want to stay around, there will have some reasons to be enthusiastic again in the future !
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#46
by
HailColumbia
on 15 May, 2006 00:23
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vt_hokie - 13/5/2006 8:56 PM
What's the compelling reason for sending humans back to the moon, other than the fact that footprints on the moon are kind of cool?
Whats the compelling reason to fly around LEO forever, other then the fact that winged spaceplanes are kind of cool?
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#47
by
vt_hokie
on 15 May, 2006 01:42
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HailColumbia - 14/5/2006 8:10 PM
Whats the compelling reason to fly around LEO forever, other then the fact that winged spaceplanes are kind of cool?
What's the compelling reason for sending 4 people to the moon for a week, other than the fact that footprints on the lunar surface are kind of cool?
Seriously, I do want to see humans go back to the moon and then beyond. This country should be able to do that while also pursuing NASP type programs. If it cannot afford to, then we've got bigger problems as a nation.
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#48
by
HailColumbia
on 15 May, 2006 02:05
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well look, its not really space exploration unless you like, ya know, explore stuff. I think we have thoroughly explored the hell out of Earth orbit. Spaceplanes will eventually happen, but they will complement deep space systems like CEV, they shouldent be the primary focus.
In my ideal world, ESAS go off as planned, including a permanant lunar base, and missions to Mars. This is all then complemented with a new space station made of a few bigass 125 ton modules lifted by the CaLV, and serviced with an OSP type vechicle. It would be nice to regain the ability to do shuttle type missions with a robot arm etc. so eventually adding some type of "space plane" to the fleet would be nice, but not at the expense of exploration.
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#49
by
wannamoonbase
on 16 May, 2006 01:13
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Grumpy old man syndrome creeping in.
I agree that CEV and VSE aren't exactly designing on the bleeding edge of a vehicle's configuration but the intent is to explore not develop a flying saucer.
There is always room for constructive criticism in any endeavour, especially in a multi billion dollar a year venture, but you also have to give credit where due.
Rutan ranted about STS for years (with lots of valid points) but now they are leaving shuttle behind to explore and its not good enough.
He looses lots of credibility over this. Perhaps too much wine, or maybe he has been using the same speech for too long to be creative in this part of his personnality.
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#50
by
kraisee
on 16 May, 2006 23:15
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The VSE is not planned to be a test program, but a fully operational program which we can truly rely upon for decades to come. That requires a totally different approach to space hardware. Truly bleeding-edge hardware is not going to be a requirement for this particular program. NASA doesn't have to re-invent the wheel to go back to the moon and to start to open-up the rest of the solar system through this program.
NASA does have a long and very respectable history of experimental programs where they push the limits of space and aeronautical research. I'm sure they will continue to do a lot of research work on the bleeding-edge of space (going to have to wait until the Shuttle is finally retired and they have more money again though).
Cutting-edge hardware research can be integrated into the VSE program, when it makes the transition from research hardware to proven reliable hardware. But the VSE does not want to be tied to completely unproven hardware which has no safety history at all. Instead, this program wants hardware we know we can rely upon for safety and sustainability. Cutting-edge stuff just can't promise either of those requirements, so we won't see a lot of it here.
The VSE will create an ever-growing and solidly reliable infrastructure for the long-term human and robotic exploration of our solar system, and promises to continue long after I pass away.
Of course, the relatively 'mundane' VSE hardware will eventually allow astronauts to do an awful lot of 'cutting-edge' missions and science all around the solar system!
If Rutan thinks he can do better he needs to put-up or shut-up. We have seen many countries and organisations saying they can do things better. Yet how many of them ever succeed?
Right now, Rutan hasn't even accomplished a real manned re-entry. Space Ship One didn't have much in the way of re-entry heating at all. NASA still accomplished that with their very first manned sub-orbital flight with Alan B. Shepard in 1961, so Rutan hasn't even matched that yet. Rutan is simply not credible in this field yet. Comments like that from his "infant" program is just "infantile". He should never have lowered himself to that level, it made *him* look stupid, not NASA.
Ross.
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#51
by
yinzer
on 17 May, 2006 00:33
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kraisee - 16/5/2006 4:02 PM
Right now, Rutan hasn't even accomplished a real manned re-entry. Space Ship One didn't have much in the way of re-entry heating at all. NASA still accomplished that with their very first manned sub-orbital flight with Alan B. Shepard in 1961, so Rutan hasn't even matched that yet. Rutan is simply not credible in this field yet. Comments like that from his "infant" program is just "infantile". He should never have lowered himself to that level, it made *him* look stupid, not NASA.
Ross.
Well, look at it from Rutan's perspective. He's designed and flew the SS1, which was a manned, rocket powered, supersonic aircraft/spacecraft, for something like $20M. NASA spent nearly 10 times that much on the X-34, and got precious little to show for it. NASA MSFC couldn't figure out how to drop the X-37 from their B-52 without it taking out the horizontal stabilizer, then NASA gave the project to DARPA who gave him a call, said "hey, can we fly this thing?", and a few months later, they did.
NASA might have been able to build spaceships better in 1961 than he can now, but the NASA of 2006 is not the NASA of the 1960s.
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#52
by
Avron
on 17 May, 2006 03:51
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yinzer - 16/5/2006 8:20 PM
NASA might have been able to build spaceships better in 1961 than he can now, but the NASA of 2006 is not the NASA of the 1960s.
NASA MSFC of 1961 is not the the same for the 2006 version, this version is in the news more often... Alas, with absolutly zero in the way of positive news..maybe I am wrong... someone post anything that NASA MSFC has done in a positive light in the last say... no you pick the period post 1975..
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#53
by
mlorrey
on 17 May, 2006 18:43
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kraisee - 16/5/2006 6:02 PM
The VSE is not planned to be a test program, but a fully operational program which we can truly rely upon for decades to come. That requires a totally different approach to space hardware. Truly bleeding-edge hardware is not going to be a requirement for this particular program. NASA doesn't have to re-invent the wheel to go back to the moon and to start to open-up the rest of the solar system through this program.
A. With the capsule design, they ARE, in fact, reinventing the wheel. Worse, it is reinventing the horse in the age of the automobile.
B. So long as NASA refuses to allow any third parties to buy CEVs on an open and free market, the solar system will not be opened. The Western US was not opened by the US Cavalry, it was opened by trappers and settlers riding their own animals and wagons.
C. So long as NASA refuses to allow third party capsule and launcher producers to compete for manned launch services to ISS on an equal footing to its own CEV, there will be little venture capital incentive to invest in private launch programs. Capital tends to avoid companies that have to compete against an established government subsidized program, which is why there are absolutely no private passenger rail services in the US beyond small boutique routes in tourist areas. Ask any US airline what it is like competing against a foreign government owned airline.
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#54
by
Jim
on 17 May, 2006 19:01
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mlorrey - 17/5/2006 2:30 PM
kraisee - 16/5/2006 6:02 PM
The VSE is not planned to be a test program, but a fully operational program which we can truly rely upon for decades to come. That requires a totally different approach to space hardware. Truly bleeding-edge hardware is not going to be a requirement for this particular program. NASA doesn't have to re-invent the wheel to go back to the moon and to start to open-up the rest of the solar system through this program.
A. With the capsule design, they ARE, in fact, reinventing the wheel. Worse, it is reinventing the horse in the age of the automobile.
B. So long as NASA refuses to allow any third parties to buy CEVs on an open and free market, the solar system will not be opened. The Western US was not opened by the US Cavalry, it was opened by trappers and settlers riding their own animals and wagons.
C. So long as NASA refuses to allow third party capsule and launcher producers to compete for manned launch services to ISS on an equal footing to its own CEV, there will be little venture capital incentive to invest in private launch programs. Capital tends to avoid companies that have to compete against an established government subsidized program, which is why there are absolutely no private passenger rail services in the US beyond small boutique routes in tourist areas. Ask any US airline what it is like competing against a foreign government owned airline.
A. wrong. RLV's are not cost effective at the low flight rates, and taking wings to the moon is a waste. As posted on other threads, trains haven't changed in the last 100 years. CEV is for lunar flight but with a secondary mission to service the ISS post shuttle.
B. Why would some one want to buy the CEV? Don't see anyone wanting to by C-17's or F-16's. The trapper and settlers had their own transportation.
C. What do you think COTS is for? NASA would like to offload ISS resupply and not use the CEV for it.
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#55
by
vt_hokie
on 17 May, 2006 22:27
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mlorrey - 17/5/2006 2:30 PM
Capital tends to avoid companies that have to compete against an established government subsidized program, which is why there are absolutely no private passenger rail services in the US beyond small boutique routes in tourist areas.
Every major passenger railroad in the world is heavily subsidized. It is a fallacy to think that if Amtrak didn't exist, private companies would be interested in getting into the passenger railroad biz. Prior to the introduction of the taxpayer funded interstate highway system and other heavily subsidized competition (including airlines and their supporting infrastructure), the private railroads in this country did manage to operate passenger trains. But now, it is not an even playing field. The only way you could have a true free market system would be for all subsidies to be eliminated for
all forms of transportation. However, if the capital investment for modern high speed rail were to be covered by taxpayer funds, there are regions of the country where an operating profit could be made. (Amtrak's Acela Express makes an operating profit, I believe, but certainly is not profitable when considering capital costs for Northeast Corridor infrastructure.)
Likewise, I think it's unrealistic to think that a large number of private companies would rapidly produce state of the art launch vehicles if NASA got out of the business. It's sort of a tricky transition, because NASA would like to have commercial providers available for ISS resupply, but it cannot bet the farm on such a commercial capability emerging. It does need to ensure that it has its own means of supporting ISS. I do agree with you, though, when you say, "With the capsule design, they ARE, in fact, reinventing the wheel. Worse, it is reinventing the horse in the age of the automobile." NASA made it clear that it was not interested in innovation when it shot down Lockheed Martin's
original CEV design and mandated the Apollo CM shape. Also, the launch vehicle design just screams pork. I never thought I'd see the segmented SRB that doomed Challenger become the basis for our next generation launch vehicle, but I guess Thiokol/ATK has a lot of political clout.
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#56
by
vt_hokie
on 17 May, 2006 22:31
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Jim - 17/5/2006 2:48 PM
A. As posted on other threads, trains haven't changed in the last 100 years.
I disagree, but if you think that the French TGV or Japanese Shinkansen is to a 100 year old steam locomotive what CEV will be to the Apollo CM, I can buy that analogy. I would say, then, that Germany's Transrapid maglev system is the NASP of rail technology. Such new technology will ultimately change the face of transportation, and the countries that invest in new technology today will be the leaders of tomorrow.
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#57
by
hyper_snyper
on 17 May, 2006 22:46
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Even though I do not agree with vt_hokie on the CEV, he brings up a question that's been bugging me ever since ESAS was released. Why did LM choose a lifting body as its original design? What was their architecture plan like. (Atlas V launcher I would imagine). I'm just curious because people keep saying lifting bodies are no good for lunar reentry speeds.
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#58
by
Jim
on 18 May, 2006 01:48
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hyper_snyper - 17/5/2006 6:33 PM
Even though I do not agree with vt_hokie on the CEV, he brings up a question that's been bugging me ever since ESAS was released. Why did LM choose a lifting body as its original design? What was their architecture plan like. (Atlas V launcher I would imagine). I'm just curious because people keep saying lifting bodies are no good for lunar reentry speeds.
Passive reentry is the requirement. The Apollo CM shaoe is marginal in this respect and the way out is a independent system, that has its own power, attitude determination, controls and thrusters/propellant. Other than launch, most accidents/incidents have occurred during entry. The current shape will right itself in most conditions but there are some that it won't. Additionally, the lifting capabilities, if uncontrolled, could result in the lift vector in the wrong direction steepening the entry.
The backup entry control system is enough (using only 2 pitch and 2 roll thrusters), even with total power loss, to determine the attitude and move the correct angle and cancel the lift vector by rolling, making a ballistic entry
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#59
by
yinzer
on 18 May, 2006 05:12
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Jim - 17/5/2006 6:35 PM
Passive reentry is the requirement. The Apollo CM shaoe is marginal in this respect and the way out is a independent system, that has its own power, attitude determination, controls and thrusters/propellant. Other than launch, most accidents/incidents have occurred during entry. The current shape will right itself in most conditions but there are some that it won't. Additionally, the lifting capabilities, if uncontrolled, could result in the lift vector in the wrong direction steepening the entry.
The backup entry control system is enough (using only 2 pitch and 2 roll thrusters), even with total power loss, to determine the attitude and move the correct angle and cancel the lift vector by rolling, making a ballistic entry
"Passive Entry" is only a rough description of the requirement. For one thing, passive entry isn't possible during re-entry at lunar velocities. For another, it turned out to be not possible to achieve totally passive entry during aborts and such, so they had to add the backup entry control system, which requires manual intervention. On page 566 of the ESAS report:
However, the requirement for monostability, in the context of the entire system, is only one way to achieve the goal of safe trim during reentry given a loss of primary flight controls.
Which makes you wonder why a fully redundant RCS system is deemed unacceptable. IMUs are pretty damn cheap, light weight, and low power these days, and blowdown monopropellant thruster systems are pretty damn simple and reliable.
I'm not sure what the actual requirement is; probably some combination of "recreate Apollo" and "seem to be learning from the Soviets/Russians". I actually think that part of the ESAS is one of the weaker ones, which is saying something.
