NASA to build Saturn VI (in-line SDLV)

[spacester]

<font color="yellow">I don't expect moon missions at that high a rate to happen before 2020. </font><br /><br />Your low expectations should not be the driving force behind U.S. space policy. We need to move away from self-limiting, self-fulfilling prophesies.<br /><br /><font color="yellow">I seriously doubt the HLV payload of 77 tonnes is neccessary for an unmanned Mars mission with a sample return.</font><br /><br />Do the math. Do we want more than a small bucket of samples? If yes, then you are wrong.<br /><br /><font color="yellow">. . . Japanese charity.</font><br />Who's talking about charity? You want to know how NASA can afford an HLV but you forbid NASA from accepting yen from Japan???<br /><br /><font color="yellow">And the alt-space industry is likely to have 25 tonne payload class rockets by 2015 that would undercut the tonnage to orbit cost of a NASA SDHLV by huge margins</font><br /><br />This is the major misconception. (Answering you as well here, no_way) The competition will not exist. They are separate arenas, separate fields of endeavor, separate markets. They will exist independently of each other here on the ground but work together up there. NASA will be doing science and exploration, private efforts will do other stuff.<br /><br />NASA competing with private launch development is a bad thing. But if the private sector can do it cheaper, what's the problem? The whole "picking winners" and Beal demise thing was about unfair subsidies to certain private customers at the expense of others. Griffin gets that whole concept, he's not going to let that happen. But as he's said, he cannot count on private efforts to achieve the capability NASA needs.<br /><br />So we'll get two Political Rockets and quit spinning in circles and move forward and outward with constant budgets. Works for me.<br /><br />Congress is reluctant to give NASA more money because they are sick and tired of no results and getting lied to. If NASA stops t <div class="Discussion_UserSignature"> </div>

 

[spacester]

Those are very valid points, kadetken, I'm not about to say that you're "wrong".<br /><br />But personally, as a guy who has been screaming at NASA to "Lead, follow or get out of the way" for years, and as a guy who had written off the first choice as a possibility, I just can't get too critical. Lo and behold, we're getting leadership fer crying out loud!<br /><br />I can't remember who first used the term "Political Rocket" here, but for me those two words sum up the whole thing nicely.<br /><br />We cannot expect NASA to build a Private Enterprise Rocket or a Perfect Rocket. What they will build are Political Rockets, there's no way around it.<br /><br />It's not like we can pretend that the Military Industrial Complex isn't going to get their piece of the action. The lions share of the action at that. That's just the way it is.<br /><br />So yes, Griffin is "picking a winner". NASA doesn't build hardware, they pay for private companies to build rockets to their specs. Somebody is going to build their political rocket for them, so how can NASA move forward without picking a winner? The key is if it's a win-win for everybody.<br /><br />The key here for me is that they are not going to compete with alt.space, they're going to enable it. That is a Very Good Thing, almost a miracle compared to 2 years ago.<br /><br />I am surprised that you think you need to design the moon base and the rest before you design the rocket to get it there. The hard part is surface to LEO, solve that, accept the payload you get from that solution and fly with it.<br /><br />Why do you want to know which private markets the SDLV will serve if you also want the program to not pick winners? That's the beauty of it to me. It's too good to be true IMO: we get the mega payloads we need to develop space, but erect no obstacles to private space flight. No one is going to come up with a private launcher that big within the same time frame, but when they do, it will be cheaper than than SDLV per pound. NASA will <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"Well your numbers aren't quite right because there are two SRBs but I get the idea."</font><br /><br />Apparently, you don't. I gave the thrust for a single SRB compared to the thrust of the SSME/ET system because you were talking about using three SRBs rather than two. That would mean <b>adding</b> the thrust of one more SRB to the system, and <b>removing</b> the thrust of the SSMEs/ET... which is what I showed. Even adding two more SRBs wouldn't make up for the loss of the thrust supplied by the SSMEs/ET.<br /><br /><font color="yellow">"Three SRBS is probably a good idea."</font><br /><br />Only in the land of the mathematically challenged.

 

[henryhallam]

<font color="yellow"><br />That means they are going to try and insert 150MT into Lunar orbit.<br /></font><br />The stack will be 150 tonnes before TLI, not after LOI when it will probably be more like ~55 tonnes - still better than Apollo but not three times better. <br /><br />This figure comes from a dV requirement of about 4150m/s to go from LEO to LLO (3190m/s TLI, 920m/s LOI, 40m/s course correction etc) and an Isp of 430s which is about average for a good LOX/LH2 rocket engine. (Final mass) = (Initial mass) / e^(4150/(430*9.8))<br /><br />(edit to correct maths)

 

[halman]

If we are talking BIG rockets, how do you maintain adequate pressure to feed the engines thousands of liters a second for several minutes? If the Shuttle had pressure fed engines, how big would the External Tank be? How much would it weigh if it had to withstand the pressure needed to supply the engines with fuel for seven minutes? I agree with your desire for the minimum of moving parts, (by the way, do you own a car with a reciprocating engine?) but I also think that our technology is still in its infancy, and turbopumps may be a neccessary evil, at least for a while.<br /><br />If your orbiter does not have wings, where will you land it? The United States does not have any areas completely empty of people that are very large, so having the orbiter end up a couple of hundred kilometers off course could be a public relations nightmare. You mention using a parasail for terminal guidance, which would probably work just fine, but has anyone ever flown one with several thousand kilograms suspended under it? If it is a true parasail, then there are no control surfaces, are there? If that is the case, how is it maneuvered? Parasails seem to require a fairly large forward velocity, so what kind of stall speed would this vehicle have?<br /><br />If safety and efficiency are the only design criteria, then capsules are certainly the way to go. But at some point in time, won't we want to have the equivalants of an aircraft's pressurized cabin, retractable landing gear, and food warming units, as well as reclining seats and bathrooms? <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>We cannot expect NASA to build a Private Enterprise Rocket or a Perfect Rocket. What they will build are Political Rockets, there's no way around it. <p><hr /></p></p></blockquote><br /><br />Thats the root of the problem. NASA SHOULD NOT be building rockets at all. Lifting mass to LEO is not where the frontier lies. As long as they are mucking about in that area, they arent leading.<br /><br />I'd have no problem if they built political moonbases or even political stations on orbit like ISS is.

 

[drwayne]

"A heavy lift should have been developed along with the shuttle."<br /><br />Unfortunately, that was not in the political or budgetary cards in the early 70's.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[mrmorris]

<font color="yellow">"I realize the need for a third stage. Your posting style is so authoritative that you are missing the point. I take that back, you are just being a jerk. SRBs would work fine. You selectively quoted me. 2 SRBs would work if you had a second stage. That is what I said."</font><br /><br />Please point out where you said that. I have reviewed the posts, and I don't see it.<br /><br />If you can show where I was mistaken, I'll apologize. Promise. If he'll agree to it, I'd like najaB to be the judge of this. Demonstrate where you spoke of additional stages before I said your concept was unworkable, and show where my numbers are off. There are several posters on the board with deathly allergies to admitting to personal fallability. I'm not one of them -- I've backtracked and made fun of my own errors on any number of occasions.<br /><br />In your initial post, here, you stated: <i>"Let's go with three SRB's. You get about 200000 more pounds of thrust while losing three engines, and an ET."</i> I see no mention of adding addional upper stages. You were specifically referring to: <i>"Two propulsion systems to get to orbit is one too many."</i>. <br /><br />I replied indicating that swapping out the SSMEs/ET for an additional SRB will not work, and that this combination would not make it to orbit. When you requested details, I supplied the stats on the total thrust supplied by a single SRB vs the total thrust supplied by the ET/SSME system and demonstrated the shortfall. You then indicated that my math was wrong because I was only counting a single SRB. I explained to you why this was both intentional and valid. Based on your design, you add one SRB, and remove three SSMEs plus the ET. Could you explain <b>why</b> you think my numbers are off, please.<br /><br />From your p

 

[henryhallam]

<font color="yellow"><br />Right, I misspoke only a little. If the plan goes as noted they will sent 150MT TLI. Certainly a fraction of that will land. Still three times a Saturn V payload TLI is impressive.<br /></font><br /><br />No, that is not correct. The 150 tonne figure INCLUDES propellant and engines for the TLI maneuver. It is NOT the payload that is sent TLI. The propellant for the trans-lunar injection will weigh 80 tonnes! Mass of the whole stack after TLI is 70 tonnes, STILL INCLUDING the TLI engines and the propellant for lunar orbit insertion. The comparable figure for Apollo was a little under 60 tonnes (empty SIVB + SLA + full CSM + full LM), of which a mere 7 tonnes made a soft landing on the surface! Of course more mass than that can be landed if you do not want to return, but we can assume the CEV crews will want to. If I had to put a number on the total mass soft-landed by the new configuration I would put it at around 30-32 tonnes BUT almost all of this will be propellant for the trip home again. "Useful" payload i.e. rover, scientific equipment, food and water for longer stays etc. might be a couple of tonnes more than Apollo had but it isn't going to be anything revolutionary. For really extended missions to the surface we will need to send a separate cargo lander first (a single SDHLV launch could soft-land maybe 24 tonnes of cargo, which is enough to keep a team of four astronauts going for several months).<br /><br />I hope this doesn't come off as being rude, I don't mean to be, I just think it's important to get the numbers right - or as accurate as possible with the data available!

 

[gunsandrockets]

"Right, I misspoke only a little. If the plan goes as noted they will sent 150MT TLI. Certainly a fraction of that will land. Still three times a Saturn V payload TLI is impressive. "<br /><br />I'm not trying to pile on or anything like that, but I think a clarification is needed. Simply put the speculated shuttle derived system is only a slight improvement over the capability of the old Saturn V, not a major improvement. Perhaps 1.5 times the payload not three times the payload.<br /><br />The proposed shuttle derived inline super-duper-uber booster would boost 120 metric tons to LEO. If the proposed CEV masses 30 metric tons and is sent up on the stick SRB to dock with the HLV payload that is a total mass in LEO of 150 metric tonnes. That grand total is only slightly more than what the old Saturn V could put up to LEO. <br /><br />Not counting the mass of the empty third stage, the Saturn V could blast 45 metric tons towards the moon. That was due to the limitations of the Saturn V third stage J-2 engine which burned LH2/LOX and had an ISP of 420, which was very good performance but not spectacular. How much payload the new shuttle derived vehicles can send to the moon depends tremendously on the ISP of whatever Earth Departure Stage (analogous to the Saturn V third stage) that is eventually selected for use. <br /><br />The new Earth Departure stage might use anything from conventional LH2/LOX to Nuclear Thermal to Nuclear electric or some combination of the three. The most likely early choice would be the LH2/LOX burning P&W RL-60 with an ISP of 465. Better than the older J-2 but not by a lot.

 

[halman]

no_way says "That's the root af the problem. NASA SHOULD NOT be building rockets at all. Lifting mass to LEO is not where the frontier lies."<br /><br />That is an interesting point of view, considering that you can count on the fingers of one hand the agencies capable of putting mass in LEO, and none of them really have heavy lift capability.<br /><br />The way the that I understand the function of government, it is to do those things which the private sector either can not or will not do. If there were several private sector organisations with the ability to put large amounts of mass into LEO on a regular basis while making a profit in the process, I would consider your statement to be valid. As much as I would like to believe that the frontier has moved beyond the basic problem of being able to get into space with the resources needed to do real work once we got there, that does not appear to be the case. Therefore, it is the responsibility of the government to learn how that can be done, which will cost lots of money without any tangible return.<br /><br />The United States likes to pretend that government does not really build the infrastructure needed for expansion, by hiding behind government loans to private industry to build railroads, or regulating the airline industry to allow healthy profits to be made in the process of running scheduled airline flights, but, in reality, it is the government that has made most of the country's growth possible, by investing in new technologies before they are perfected, redistributing wealth to allow services to be extended to areas that would not be profitable to serve, and so on. I personally believe that many of the problems this country is currently facing are a result of the government failing to invest enough in space flight, which has prevented the economic growth that would have followed such investment.<br /><br />No private sector company is going to build a rocket that there is no demand for, and there will be no <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[spacester]

Well said halman. You finished with<br /><br /><font color="yellow">Which means that the real frontier is still that first 300 kilometers. </font><br /><br />To which I would add<br /><br />Yes but not for long! <img src="/images/icons/laugh.gif" /> <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[halman]

In many respects, we would be better off to pretend that the Apollo program never took place. It has had little or no impact on the development of ways of getting back and forth between Earth and orbit, it did nothing to further the development of the Moon, and it creates a false sense of accomplishment. Sure, we put some people on the Moon, but we couldn't do it again tomorrow, and those folks were at the end of a very long shoestring. Apollo was a stunt, which probably set back the exploration of space by at least 30 years. It makes no difference now if the Saturn 5 could put X number of kilograms in orbit, because we don't make those anymore, and there are not any lying around that we can use.<br /><br />In many respects, we are starting from scratch, or we should be, because we have not really accomplished anything yet. We have no Cheap Access to Space, we have no healthy, growing space station, and we have no base on the Moon. We do not have a launch system that we have faith in to deliver big chunks of mass to Low Earth Orbit, and this is after flying for over 40 years and spending hundreds of billions of dollars. All that we have really accomplished is learning how to convert Inter Continental Ballistic Missiles into commercial launch vehicles, capable of lifting small payloads to very Low Earth Orbit.<br /><br />If we don't get this right pretty soon, I think that we are going to run out of chances, and we are already running out of money.<br /><br />Gee, that felt good to say! <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[halman]

Thank you, Spacester! It is nice to know that some people actually read my posts, even though they can be a bit long-winded. But I feel that it is important that people understand why a statement like "It is up to government to develop heavy lift launch vehicles," can be made with some degree of certainty.<br /><br /> <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[mrmorris]

<font color="yellow">"Nothwithstanding my spelling mistake on add ( not ad ) you can read it for yourself. "</font><br /><br /><b>After</b> I provided numbers demonstrating that your initial proposal would have resulted in a suborbital rocket, you tack on "Oh let's add another stage", and still claim my numbers aren't right. Can you spell 'cop out'? <br /><br />That's enough on this topic.

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>No private sector company is going to build a rocket that there is no demand for, and there will be no demand for heavy lift until heavy lift has been used to create an industrial base in space. <p><hr /></p></p></blockquote><br />Heavy lift is not a set-in-stone requirement. <br /><br />Orbital docking of modules, refuelling, crew transfer and eventually construction of large-scale structures will inevitably become necessary at some point, if we are to become a spacefaring civilization. Making your rockets bigger just pushes this point temporarily forward in time.<br /><br />Launch market has currently enormous potential capability for lift, IIRC EELV production lines for instance were designed for 50 launches a year and thats only US capacity. Thats one of the reasons why EELVs are expensive right now, because they have this huge infrastructure investment they are trying to recover with couple launches a year.<br /><br />Coming back to our argument where the Frontier lies .. commercial market has the capacity to lift, satellite launches are occuring all the time and there are countless satellites already orbit. This has been so for past several decades. <br />I'd say LEO/GEO are pretty much a conquered frontier. ( what it could benefit from, is economies of scale resulting from much higher activity levels, but thats beside the point ) <br /><br />Another problem with that heavy lifter idea is that its putting the cart before the horse again. How can you tell which transportation device you need if you just know your destination but havent decided what are you going to do there ?<br />What are those huge components that absolutely and inevitably have to be launched on this new white elephant ?<br />And btw, as we have discussed before, anything, and i mean anything that is going from LEO to Lunar surface is going to be at least four parts propellants and one part something else by mass. So how come all this propellant cannot be

 

[halman]

Until the regular passage of people to and from LEO has become a reality, and the vehicles used have some reliability, LEO is going to be a frontier in my mind. This is all about getting PEOPLE into space, and we are still not very good at that. Because weight restrictions can compromise safety, I think that it is better to create a launch vehicle which can handle a large payload to replace the shuttle, rather than hoping that we can keep the crew module design light enough to fly on an EELV.<br /><br />If we are going to create an infrastructure capable of supporting in-orbit transfers, refueling, etcetera, we will need the ability to put big stuff up there if we want to get done any time soon.<br /><br />Heavy lift is not set in stone, it is true, but it will sure make things easier.<br /><br /> <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>Until the regular passage of people to and from LEO has become a reality<p><hr /></p></p></blockquote><br />It's been a reality since 1961, 12 April. Thats 44 years, a very long time IMO.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>and we are still not very good at that<p><hr /></p></p></blockquote><br />True. We have a fataility rate of 4-5% amongst all flown astronauts. Thats probably worse than sailing the high seas in the era of Columbus.<br />Further improvements can only come from increased flight rate, i.e much larger experience base. Flying _any_ vehicle once or twice a year is not gonna work out the kinks and problems, ever. Also, building a new launch system once in several decades is not going to get us to reliable transports. If auto industry did that, we'd still be driving Ford T's, if that.<br />Thus, this "frontier" desperately needs a big boost in flight rate and severeal iterations of vehicle developments. This is not going to come from NASA or any other government agency, thus, IMO this "frontier" belongs to private sector. NASA will only harm this industry with its inevitably low flight rate HLVs ( because there simply arent that many payloads to go around )<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>If we are going to create an infrastructure capable of supporting in-orbit transfers, refueling, etcetera, we will need the ability to put big stuff up there if we want to get done any time soon. <p><hr /></p></p></blockquote><br />Huh ? Why would that be ? Which design of orbital tug, orbital fuel depot or fuel container that you have come across wouldnt fit on currently operating "medium" launchers ?<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>Heavy lift is not set in stone, it is true, but it will sure make things easier<p><hr /></p></p></blockquote><br />This may only seem so in the short run. Saturn V made apollo "easier", but ultimately unsustainable, because noth

 

[starfhury]

I think Halman is right. We've just made trists into space. We've not conquered anything yet. We are still running steam powered cars when we should have already switched over to gasoline. The bottom line, as I've stated before and reconfirmed in other thread, is power density. Even a non scientist, accountant type such as O'Keefe recognized this right away when he allowed Promethius to continue on. Our current engine technology does not extract enough energy out of available propellants to reduce our prop mass budget. That's what is putting the real hurt on us. We have to use so much prop to accomplish so little. We need to develop NTR technology until something even better comes along. This is why we still need NASA. Due to government regulations and prohibative costs, only NASA would be allowed to commision and work on such a system. We need to find a way to scrub the NTR exhaust and a way to minimize the total mass used for effective shielding. <br /> <div class="Discussion_UserSignature"> </div>

 

[aaron38]

NTR will never see the light of day. They can't even build wind turbines in Wisconsin because a tweety bird might get whacked. You think the enviros are going to allow a flying nuclear reactor??<br /><br />Maybe if they militarize the project, do it in total secrecy and tell the public only once it's in orbit, it MIGHT get off the ground. But I doubt even that.

 

[starfhury]

Then maybe space exploration isn't for us after all. If we are unwilling to take any risks what's the point? If we have to build an artificial island out in the middle of the ocean somewhere to avoid over flying populated areas on launch and retun maybe that's what we should do. The problem is that we can't escape the math. We need to move to systems with even greater ISPs. If we can double our ISP for similar weight, we can about double payload capacity. We would in fact need less to do more, which can reduce cost thus opening the space frontier. Do I like nuclear, no, but it doesn't stop me from recognizing that it's the clearest next step we can take given our current situation. <div class="Discussion_UserSignature"> </div>

 

[tap_sa]

<font color="yellow">"Do I like nuclear, no, but it doesn't stop me from recognizing that it's the clearest next step we can take given our current situation."</font><br /><br />What's wrong with solar thermal? Basic NTR is nothing but a simple reactor that spews out it's coolant through a nozzle. The same effect, heating up H2 to 2500-3000K, can just as well be accomplished by concentrating mirror.

 

[nacnud]

How about solar electric propulsion? Ion thrusters have an ISP of 6,000 or so. Use solar electric to slowly move large chunks of infrastructure around Earth-Luna space and nuclear electric for interplanetary mission where there is a much lower change of a hot reactor falling back to Earth.

 

[starfhury]

I did not know solar electric and solar thermal were useable for anything beyond orbit or inside the orbit of Mars. I'm not sure our astronauts, tough and brave as they are want to spend months in the void of space exposed to unnecessary risks because we don't want to use NTRs. I'd love to have the ISP of that ion thruster though. If only we could get the actual thrust levels a lot higher while keeping it's efficiency. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

The problem with those impressive numbers is they produce minimal thrust at a specific time, over time, Ion engines produce a great amount of very efficient thrust, but in the short term you have to look at the mass being accelerated, the higher the mass the more immediate thrust is needed. A good example is the Shuttle SRB, it has a relatively low ISP, but it is released over a short period of time. The SRB imparts it's energy in a couple of minutes while an ion engine with the eqivelent total ISP imparts it over a much longer period. That's why Ion engines can produce great speeds by imparting a small amount of thrust over a long period of time.<br /><br />The same would hold true with an NTR. If you use generated electrical power to vaporizes a mass, what an Ion engine does, you get a little thrust over a long period of time, if you want to go somewhere quickly you have to vaporize that amount of mass over a short period to provide the ISP immediately, rather than gradually. What that means is you would have to have a lot of mass,as a colant and reactant to make Nuclear work. Think of it like the radiator in your car, the reaction in the core produces a lot of heat, you pump coolant through it then expell it and it produces a lot of immediate thrust and speeds you on your way. The same would apply using a sealed coolant loop and a reactant to absorb and expell the heat.<br />The problem is you couldn't possibly carry enough reactant, considering the heat a Nuclear reactor would produce. <br /><br />The simplest means is the current means; a lot of thrust to establish a course then a lot of thrust to decelerate and enter an orbit. Chemical engines work very well and don't have anywhere the mass Nuclear engines would require <div class="Discussion_UserSignature"> </div>