Questions about NASA returning to the moon

yoda9999 · Jul 31, 2006

According to the NASA animation, the new moon vehicle that leaves Earth orbit includes a departure stage, the CEV and the lunar lander. It looks like Apollo with the added departure stage. Why doesn't NASA just build a single ship that can leave Earth orbit, land on the moon, and return to Earth orbit all in one piece? Is NASA using the Apollo approach to save time and money, so it won't have to experiment with a totally different method of returning to the moon? I know saving money is important, but it just seems like the new NASA design doesn't introduce a really new concept of going to the moon. I guess we still have to wait a few decades more before we see something like that moon ship in 2001 A Space Odyssey.

qso1 · Jul 31, 2006

Thats the correct guess. Once propellant is depleted after necessary engine burns, you normally jettison the propellant stage or keep it for refuel upon Earth return. Refuel upon earth return has yet to be done however and still involves dragging an empty propulsion stage back. Jettisoning the stage is the cheapest way to do it for now. Same principal applies to launching from earth to low orbit. Multistage rockets do the same. Jettison each stage after it has done its job. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

Aetius · Jul 31, 2006

New doesn't necessarily mean better. The sailboat that wins the America's Cup has basic elements in common with the ones Homer's Greek heroes used to journey to Troy. There is obviously a world of difference in the details, but the bottom line is that common requirements dictate that all sailboats will have a certain kind of appearance. The same principle applies to spacecraft, in my opinion. That's why I think so highly of the Soyuz vehicle, and applaud the Chinese for using the same basic design for their own human spaceflight program. It's not about spaceships looking all science-fictiony. It's about bringing the humans back home alive. The Space Shuttle is a sleek and sexy vehicle, but given a choice I'd rather leave this rock in a Soyuz or Shenzou any day of the week.

cuddlyrocket · Jul 31, 2006

"Is NASA using the Apollo approach to save time and money, so it won't have to experiment with a totally different method of returning to the moon?" Yes (although slightly modified). They know it works, and development costs and (more importantly) risks are minimised. Once in place, it can be improved. "Why doesn't NASA just build a single ship that can leave Earth orbit, land on the moon, and return to Earth orbit all in one piece?" Because they're not stupid. Such a ship would be enormous and the cost of each mission (despite it presumably being re-usable) would be greater than that of building the far smaller CEV/LSAM afresh each time (although the CEV is partly re-usable). "I guess we still have to wait a few decades more before we see something like that moon ship in 2001 A Space Odyssey." Filmic science-fiction is a poor guide to reality.

dreada5 · Jul 31, 2006

I totally agree 100% with aetius Soyuz is a good example of hardware that works well, is reliable and gets the job done. I'm not doubting NASA's capabilities, but when the russians (and partners) finally decide the way forward for the Soyuz replacement its gonna kicka$$! Because its foundations will be tried and tested technology with some updated, state of the art systems. Of course NASA has finally caught on to the game, and is going that way with its Ares 1 vehicle. Bout time!

dreada5 · Jul 31, 2006

<blockquote>In reply to:<hr />Filmic science-fiction is a poor guide to reality<hr /></blockquote> Although they're not the same, they do feed off of one another at times.

bdewoody · Jul 31, 2006

I think the Moon Ship in the movie "2001" was used only between the space station and the moon and was never intended to transit to the surface of the earth. If we ever have such a space station I would think such a vehicle would be practical. As I recall there was a winged vehicle that transported personnel from the earth to the space station. To me a capsule that lands under parachutes is a good design for a lifeboat but is not practical for a future where more than 3 or 4 people at a time will be on board. A lifting body that lands on a runway will be needed for larger crews. <div class="Discussion_UserSignature"> Bob DeWoody </div>

qso1 · Jul 31, 2006

Excellent points all. Yes the 2001 lunar craft was a shuttle between the wheel shaped station and the lunar base. Keeping in mind that at the time the movie was made. A much more optimistic space future was believed to be in the works. And yes a capsule will be good for small crews. Just as Soyuz is now. But even the Russians were planning to build a space station of large proportions that would require their shuttle to take large crews to and from. This before the Soviet Unions collapse. Now such a future depends largely on private enterprise and or NASA breaking the cost barrier. Imagine what the 2001 space infrastructure would cost under the present government approach to human spaceflight. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

yoda9999 · Jul 31, 2006

One thing I'm concerned about is all these jettisoned components, spent fuel tanks, left behind in space. Seems like we're leaving behind a lot of stuff that can be reused. This increases space junk. Are the departure stages reusable in any way? Are they refueled in orbit or do they return to Earth? Is the lander left in Earth orbit indefinitely? Would be interesting if NASA has some "return container" for large components like the lander, but I suppose that maintenance on it could be done by astronauts. The NASA animation also shows the lunar lander leaving behind some fuel tanks on the moon. Do new tanks have to brought up everytime a CEV to the moon is launched? Are those tanks and the CEV launched on the same booster? Sorry if I'm asking too many picky questions. Now, I'm not saying NASA should build a "sci-fi" moonship, like the one in 2001 A Space Odyssey, just to build something new and fancy. But it just seems like a "one-piece" ship is the most direct way of getting to the moon, albeit much more expensive and heavy. And we would have a chance of learning a new way of making a spaceship. I guess can't do that until we have some form of propulsion which would make doing that efficient.

themanwithoutapast · Jul 31, 2006

"One thing I'm concerned about is all these jettisoned components, spent fuel tanks, left behind in space. Seems like we're leaving behind a lot of stuff that can be reused. This increases space junk. " Apollo EDS stages are not space junk in the sense of 'bad space junk' - some of them were deliberatly crashed on the moon - the impact can be exploited for scientists if observed. I guess the same will be done in the new Moon project.

qso1 · Jul 31, 2006

yoda9999: This increases space junk. Me: This will be far less a problem for lunar missions. One reason, the stage that sends them on the way to the moon will push the CEV/LSAM combo to earth escape velocity (24,500 mph). When the propulsion stage separates, it goes into its own solar orbit or crashes into the moon for moon quake study if the TLI (Trans Lunar Injection) burn is done the same way Apollo was. The departure stage cannot return to Earth once escape velocity is achieved without a crapload of additional propellant. Like the Apollo LM. The LSAM is divided into two peices. An ascent stage and a descent stage. What you saw on the moon was the descent stage. This stage would sit with propellant tanks empty on the moon, the ascent stage carries the crew back to the CEV in lunar orbit. Once the crew transfers to the CEV, the LSAM ascent stage is jettisoned. And yes, a new descent and ascent stage would be part of each new LSAM mission and they are launched together on the Aries 5 while the next CEV goes up on the Aries 1. The problem with reuse of the stages is that once emptied, the stage is just dead weight being drug along which would of course, severely limit the performance of remaining fueled stages or vehicles. Example. The departure stage if kept after the TLI burn, will impose a severe drag penalty on the CEV/LSAM stack and so on. If you remember Delta Clipper, the subscale Single Stage To Orbit (SSTO) vehicle tested in the early 1990s, a slightly larger version of this type of vehicle could serve in place of an LSAM and be totally reusable theoretically, but the propellant required would limit payload to the lunar surface and especially any payload launched from the lunar surface. In addition, the development of SSTO technology is still the stuff of future spaceflight. More expensive to do than just doing the modernized Apollo. NASA never builds something for the sake of being new and fancy <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

Aetius · Jul 31, 2006

Oh how I hope this doesn't get cancelled by the next administration. It would be great (without a trace of sarcasm on my part) if we could afford 4 support flights per year to maintain a small base on the Moon. I know that's beaucoup dollars, but hopefully once the Shuttle's gone and somehow we figure out what to do with ISS, we can afford it somehow. I'm pessimistic, but I can still hope.

halman · Jul 31, 2006

yoda9999, Basically, so much time has elapsed since the days of Apollo that we are going to have to do the whole thing all over again. We will have people sitting on top of a great big rocket that will be thrown away, we will have them go directly to the Moon and back, and they won't be able to take very much with them, or bring very much back. It is all for show, to let the world know that the United States can still do what it did 40 fourty years ago. It ignores that International Space Station as a base in space to use for exploring space, because that would mean spending more money on a project that the United States does not have sole control over. It does not require creating any new technology, because we don't have the engineers any more to do that sort of thing. It is not a sustainable approach to developing the Moon, just another stunt, showing off to those who know no better. It ignores what happens when the ignorant public sees expensive rockets thrown away again and again, because it is not meant to be a long term program. When you think of the Vision for Space Exploration, remember "Mission accomplished!" <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

yoda9999 · Aug 1, 2006

Thanks everyone for the helpful responses! Halman: I share your cynicism. So under the new NASA plan, each lunar mission will require 2 launches from Earth. Ares I: CEV capsule, service module Ares V: departure stage, lunar ascent and descent modules And the only thing reusable here is the CEV. So we have to manufacture everything (except the CEV) for every lunar mission. I guess this is all cheaper than designing a radically new fully reusable spaceship, but it sure isn't pretty. Two Ares launches per mission? Sheesh... Well, I suppose the bright side is that Ares V can send things to Mars?

lampblack · Aug 1, 2006

And the only thing reusable here is the CEV. So we have to manufacture everything (except the CEV) for every lunar mission. Hey... the five-segment solid rocket boosters will be reusable, too. In fact, most of the Ares I will be reusable, except for the second stage and the service module. As for the Ares V, the throw-away parts include the liquid propellant tank (like the shuttle), plus five relatively inexpensive RS-68 engines. Not perfect. But also not that bad, actually, in the throw-away world of rocket science. <div class="Discussion_UserSignature"> Just tell the truth and let the chips fall... </div>

vt_hokie · Aug 1, 2006

Halman: I share your cynicism. As do I.

j05h · Aug 1, 2006

It's not that the new Moon rocket is thrown away, the problem is that they don't plan on re-using any parts of it in space. I don't care if the ARES-V isn't returned to Earth - the stages that end up in space should serve as wetlabs and storage tanks. With a slightly different flight plan, those Earth Departure Stages could form the basis for a Lunar or Lagrange-Point fuel depot/base. I share your cynicism. Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

dreada5 · Aug 1, 2006

I think Halman is too pessimistic. NASA have made progress since 40 years ago. The ISS is cool, something that excites many everytime they see it. Remember there was a time when there was no permanent human presence in space (lol, that sounds like the script from 2010... "Your children will be born in a world of two suns...You can tell them that you remember when there was a pitch black sky with no bright star"). <img src="/images/icons/laugh.gif" /> Obviously, everyone thinks NASA should have achieved more by now, done things differently, but like it or lump we have made some progress and as unbelievable as it seems now... we may have basic, international moonbase (IMB!!) one day. <img src="/images/icons/smile.gif" /> Remember, there was a time when space stations where just temporary, short-lived affairs.

qso1 · Aug 1, 2006

I agree with much of what you said. But if we do a moonbase, I think the cost should be spread a bit more evenly because going international on ISS was no money saver. At the same time, there are positive reasons to go international that transcend pure economics. I also think some of what Halman says is true. Our knowledge base is not what it once was but I still think we have enough people working for NASA who can get NASA through the relatively slow times. And I say slow because I'm one of those people who think NASA made progress, just not as much as I'd hoped to see by now. But...thats due to three decades of budgets that barely kept pace with inflation more than anything else. The shuttle is a technical accomplishment that besides America, only one other country achieved. Our shuttle has served well while the Russian shuttle became a victim of severe economic constraints following the collapse of the communist system that led to its 1993 cancellation. The ISS is certainly a major achievement which has shown the world we can live and work in space. The shuttle failed to live up to the economic promise once made of it, as did ISS. But again, one has to look beyond simple economics to see what we gained by both programs. One example, without the shuttle, we would not have had Hubble and the revolution in astronomy that came with it. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

themanwithoutapast · Aug 1, 2006

"I agree with much of what you said. But if we do a moonbase, I think the cost should be spread a bit more evenly because going international on ISS was no money saver. " That has much to do with the problems with the Shuttle - if the ISS would still be an entirely US space program and would not have been cancelled by now it would either cost NASA the same amount of money + what ESA, CSA, JAXA and Roskosmos are paying or it would just be smaller and would cost the same amount NASA pays now. The major difference would be that the station would probably have been unmanned since Columbia's disintegration and would now be rather, rather close to falling out of orbit and disintegrating itself. And by the way, in my opinion an international moon base should not really be a 'money-safer' rather lead to a more capable base for more people as if it just would be a US-only facility.

qso1 · Aug 1, 2006

Actually, I would say it had more to do with not designing the ISS to be lifted to LEO on a few Shuttle "C" or other HLLV flights as opposed to however many shuttle flights have currently been required to get the peices to orbit. themanwithoutapast: The major difference would be that the station would probably have been unmanned since Columbia's disintegration and would now be rather, rather close to falling out of orbit and disintegrating itself. Me: "At the same time, there are positive reasons to go international that transcend pure economics." When I made this statement, what you mentioned about Columbia was one of the scenarios I had in mind. The reason I said an international project is no money saver is that in the 1970s, everyone who was criticizing NASA human spaceflight spending used to say we would save all this money if we went international. Carl Sagan was an advocate of this approach partly for the promised cost savings. ISS began as a space staion in 1984 that was to be completed by 1992 at $8B dollars. It ended up being redesigned so many times, which drove costs up, that its now thought to be close to $100B dollars. Even now, you always here lines like..."We can't go the moon alone" No single nation can afford the cost. IMO, affordability is relative. We can afford Iraq rebuilding at $100 or more Billion a year yet we cannot afford to develop a space station or lunar base on our own if we had to. Of course, we don't have to go it alone and again, there are reasons to go international that transcend pure economics. I agree as well that a moon base should not have to be sold solely on the merits of cost savings. Especially when one considers the other areas where government wastes tremendous amounts of money which wipes out anything that could be saved by cutting NASA spending. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

qso1 · Aug 1, 2006

aetius: Oh how I hope this doesn't get cancelled by the next administration. Me: You and me both. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

BReif · Aug 2, 2006

I too hope that the new Vision for Space Exploration (VSE), and the direction that NASA is heading does not get cancelled by the next administration. There is cause for concern. Since this was a Bush program, and since so many are politically motivated by all things anti-Bush, this program could get cancelled just because it was Bush's brainchild. The good news is that the US Congress voted and approved a NASA authorization bill, and endorsed the VSE as US policy, and it had broad bi-partisan support. One of the few items that have had support from both sides of the isle in quite a long while. If you want to make sure VSE stays alive, write to your senators and congressional represenatative to that effect. During the next presidential elections, write to the candidates and express your views. Force them to make a statement about where they stand on it.

themanwithoutapast · Aug 2, 2006

Sorry, but the VSE was certainly not "Bush's brainchild". The Bush administration works together with NASA as all previous US administrations did. Somebody said they need a new goal, NASA and people in the Bush administration/Republican party worked out the details of the VSE. Then a PR guy wrote Bush's VSE speach from 2004, which Bush read to the public. I doubt Bush does personally know very much about the details of the VSE himself, after all he is no engineer.

yoda9999 · Aug 2, 2006

I'm sure Lockheed Martian and the other companies will spread the jobs around enough states to ensure no congressman or senator wants the program to be axed. <img src="/images/icons/wink.gif" />

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