Feasibility of Baker's Ares today?

najab · Mar 29, 2005

Shyningnight more or less summed it up. The Shuttle NASA wanted was a small 6 seater crew-only vehicle, with a manned, liquid fueled, flyback first stage. In their plan, heavy lift would have been provided by a Saturn V with a reusable first stage.When Congress said no, the Air Force stepped in and said they would help fund the Shuttle as long as it could also carry a 60-foot long, 22,000 pound payload into a polar orbit and return to the launch site in a single revolution.This necessitated a large payload bay, large wings (to get the 1000 mile cross-range required to return to the launch site), and solid rocket boosters (for the higher thrust, lower cost). Weight constraints also precluded a crew escape system.

smradoch · Mar 29, 2005

Thanks for info. But it would be totaly different vehicle. Similar 6 crewed vehicle will be Russian Cliper to ISS, so Americans can buy tickets when necessary. But I think soon (10-20 years) there will be more private options for LEO. So there is no need for NASA to bother with that when CEV capsule will be able to do that (for 3 or 4 crew) as well.

yurkin · Mar 29, 2005

smradoch & gofer No offense but it really doesn’t read like u know what you are talking about. NilsTycho Okay to your question. I think the ASRMs are probably the easiest part. Ares 2,194,600 kg STS 2,029,633 kg That’s just an 8% percent increase. With a reduced payload you could probably use the exact same SRMs as those used on the shuttle. Also the SRMs have been improved over the extent of the shuttles service. There are two reasons I can see why STS is not fitted with ASRMs, firstly there are safety concerns. The second is that the center of mass of the STS is not on the center of thrust for the solids. If the SRMs were stronger then STS will pitch up onto its back. With Ares there is really no limit to how big you can make the solids. The biggest technical problem I guess would be the SSME. Being able to manufacture them on a reasonable budget would be difficult. The biggest problem period would be competition from the EELVs. Lockheed/Boeing spent a lot of money building these and I think they would want to see a return on that investment before they were convinced to start another project. And there’s really nobody else that has the capacity to build this.

najab · Mar 29, 2005

>There are two reasons I can see why STS is not fitted with ASRMs, firstly there are safety concerns.There is one reason, and one reason only why the ASRM was not used: Morton-Thiokol has a powerful lobby in Congress. The ASRM was actually much safer than the RSRM (fewer, better designed field joints), but it was dropped when it was nearly complete after a lot of money had been spent on it.

smradoch · Mar 30, 2005

Yurkin calm down, maybe Ares can use Shuttle SRB, but with lower payload and ASRM would definitely mean more development costs. But interresting point is somewhere else. Just compare three basic possibilities (mabe there are more of them) Ares: 2 ASRM, modified ET, 3 SSME, completely new upper stage, new big fairing for cargo mission, new EDS for Lunar mission or upper stage would be used? Modified infastructure. Payload 120t to LEO or so. Possibly human rated (ASRM?) Smaler SDV: 2 SRB, modified ET, 2 RS-68, new fairing for cargo mission, new upper stage with RL-60 serving as EDS, possibly upgradeable, modified infrastructure. Payload cca 80t to LEO. Why not human rated? Shuttle C: 2 SRB, ET, 3 SSME, new design of cargo pod, new EDS necessary, slightly midified infrastructure. Payload cca 77t to LEO. Not easily upgradeable (maybe ASRM?) Not human rated

gofer · Mar 30, 2005

Yurkin, That's nice, that's exactly what I said in fact, that Ares is feasible if enough money is thrown at it. With what specific (non)shuttle parts is irrelevant. I think this amount of money will really cut into the exploration budget, tie the architectrue to a single vehicle and leave NASA broke to actually build anything to launch with it... and is, thus, not feasible. No-one has provided a cost estimate, I think it's got to be more expensive than the Shuttle-C. Just because I've seen nothing better in this thread as an esimate. Talking about how much stuff it can lob to the moon and using what motors without mentioning costs to develop, manufacture and operate it is pointless because the budget is given. But fun, I guess. However, if you know for a fact that it'll cost less than $1B to build, that's great and I think NASA should start immediately. Your notion that the EELVs are the main obstacle, I find strange - why would Boeing and Lockheed refuse a multi-billion dollar gov'mint contract. The new HLV would be one mother of a gravy train for the corporate types. The EELVs have their own customers (telcoms and DOD) and separate funding quite unrelated to NASA, and there is no competion in the HLV class payloads whatsoever. Who wants to launch 120 tonn sattelites? No, the HLV, if built, will be used 1, 2 times a year tops, unless NASA gets Apollo style budgeting. Yeah, right.

gofer · Mar 30, 2005

I'm dying to see what NASA selects as the CEV architecture (proposals in May, selection in summer sometime?) Drawn by the very same Boeing and Lockheed (is t/Space still in the running, dunno) That'll seal some fates.

najab · Mar 30, 2005

If I was designing a HLLV, using as many existing (or near-existing) components as possible, one configuration I would consider would be four SRMs clustered around a Shuttle ET-derived tank, with a top-mounted payload module.I would use a pair of 5 segment and a pair of 4 segment boosters. On the bottom of the ET I'd use either 3 or 4 RS-68's - with a nozzle adapted to give a higher expansion ratio, these would run at low thrust until the first pair of SRMs burned out and then ramp up to 100% as the 5 segment motors are tapering off. If memory serves correctly, the 5-segment booster only burns about 10 seconds longer than the 4 segment, so staging could be symmetrical for all four motors. The boosters would not be recovered.The central prop tank would obviously have to be significantly strengthened - both due to the increased thrust and the top mounted load - but I'd keep the diameter the same as the ET, so as to make manufacturing and transporting it possible with the existing facilities. It would be taken all the way to orbit, like the STS, and either used as an orbital facility, or de-orbited - the engines would not be recovered.The payload module would use RL-10(s) for on-orbit manouvering, TLI or TMI burns.Of course, if I'm not constrained to using existing components - Sea Dragon all the way!!!

smradoch · Mar 30, 2005

NajaB Your proposal would be for really heavy payloads and you forget huge modifications to the launch pad. Maybe completely new pad. Also ET would have to be much bigger because of lot of engines (min thrust is around 60%). To be honest I think you weren't serious.

najab · Mar 30, 2005

>Your proposal would be for really heavy payloads...Yes, yes it would... (he says with a faraway look in his eyes).>... and you forget huge modifications to the launch pad. Maybe completely new pad. Yes, actually I am proposing that we, well they, finally build LC39C - it was planned for use with the Nova booster.>Also ET would have to be much bigger because of lot of engines (min thrust is around 60%).I'd have to check that because it's 4 engines at 60% as opposed to 3 at 109%. Truth be told, I didn't do any calculations, for all I know two RS-68's might be enough, it depends on the staging velocity.>To be honest I think you weren't serious.Serious, yes. Seriously expect it to be built, no. I just like to think big: if we're going to do heavy-lift, let's do heavy lift!

dan_casale · Mar 30, 2005

>>....I would consider would be four SRMs clustered around a Shuttle ET-derived tank, with a top-mounted payload module.<< We'll take ten for every Earth-Mars window, over at the design a mission to Mars thread.

gofer · Mar 30, 2005

Well, if we want to do any sort of SDV at all we better hurry... because NASA considers storing just enough STS stuff for the 28 ISS flights and terminating further contacts for ETs, SRBs, etc... http://www.spaceref.com/news/viewnews.html?id=1012 And once the tooling and the staff for those are gone it'll be much harder to bring them back, I think. No-one will keep the ET/SRB manufacture around just in case, once they are gone they are gone.

scottb50 · Mar 31, 2005

I would thing having three of four launches, from the Earths surface to support a mission to Mars would not be unreasonable. If failures or other problems intervene, as long as the people are the last payload to LEO it has a pretty good chanced of working. <div class="Discussion_UserSignature"> </div>

mattblack · Mar 31, 2005

The Ares design is fairly sound, if you consider it was conceived before 5-segment SRBs, Aluminium-Lithium E.T.'s and RS-68 engines existed. In Robert Zubrin's "Case For Mars" book he mentioned the latest design as having 4x SSME and 2x ASRMs as the first stage with 1x SSME powering the upper-stage. This would give a payload of 135 tons to LEO and 45 tons Earth escape. This is of course assuming that an inline Shuttle-derived concept would be built with plenty of funding, because although inline configuration is where the performance is, inline is where the COST is. Why? Changes to the Crawlers, External Tanks, VAB and Launchpads 39A & B. Cost?: TENS OF BILLIONS. Remember that: cost is the overwhelming factor here to politicians. Not what's the best design (Delta or Atlas derived, Clean Sheet) but C.O.S.T. Although it's not the best or most efficient design, a side-mounted SDV requires NO (or very few) changes to the Crawlers, VAB or launchpads. Cost of that? Negligible or even NONE. There are limits to how heavy a payload the side-mounted SDV --- alright, Shuttle C(!) can carry because of center-of-gravity, torsional loads, payload fairing aerodynamics etc. If a Shuttle C-type vehicle were to use normal 4-segment SRBs and 3x disposable (old) SSMEs, plus the Aluminium-Lithium E.T. this would essentially be a man-rated 80 ton-to-LEO booster. But if you take the side-mounted SDV to it's full upgrade potential with 5-segment SRBs, 3x RS-68s (expendable) and less insulation on the ET (no Shuttle tiles or RCC to protect), plus a kickstage powered by 2x RL-60s, then here you'd have a 87 ton-to-LEO heavy lift booster for the shortest possible development time, least investment and least effort to man-rate. With such a vehicle, you'd have a Lunar expedition in one launch and a Mars expedition in two: Pad 39A launches the 45 ton Marscraft with it's 40 ton Mars injection kickstage and Pad 39B launches the main Mars inj <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

smradoch · Mar 31, 2005

mattblack I agree that SDV should be very cheap to have support in congress. But I think that Shuttle C is not and cann't be human rated, because even recent Shuttle is not human rated. There is ISS to partialy fix that problem. Side mounted SDV (or Shuttle C) can have 3 SSME or 2 RS-68 nothing else (RS-68 is quite big and powerfull engine). 2x RL-60 for 80t to LEO and for earth departure stage seems too much (depending on flight path) and it will be more problematic to build-in to the side mounted cargo fairing. I think clasical Shuttle C is the best option from side-cargo-mounted SDV. The problem will be a cargo. You will need 2 piloted (2x80t) and 2 cargo (2x80t) mission a year for Moon around 2015-2020 and Mars is even further around 2030 when we are optimistic. So we need rocket which could launch both humans and cargo 4 times a year available in 10 years. 80t is far enough, because 4 launch/year is optimum from technical, staff and financial point of wiev. It means that you would launch cargo to the moon and after 3 months crew which lands near the cargo. Every year you will need 4 SDV, 4 same EDS (earth dep stages or upper stages of SDV), 2 CEV, 2 LunarModule, 2 cargo (habitat, lab, modules for lunar base...)

mattblack · Mar 31, 2005

I agree that in the absence of a Saturn V class launcher, the cargo and crew may have to be split up. Especially if some sort of Lunar Orbit Rendezvous is used, with a seperate Lander and CEV/Mothership. It seems to me that the CEV should have the ability to be launched on more than one rocket, be that a Atlas V or SDV. I reckon that the best design for a CEV would be similar to one that Nasa has proposed before as one of their best "paper spaceships": the blunt-biconic shape that could be used for a variety of missions at the Moon or Mars. For a lunar mission it would have enough propellant for a direct descent and return to Earth. For Mars with its higher gravity and atmospheric braking, it need only carry enough fuel for a landing only, as there would be a seperate Ascent ship. For the Moon, a pre-landed Habitat module or attachable kevlar inflatable would serve as living quarters. As you pointed out, other cargoes of instruments, supplies and tools could be sent on ahead. Von Braun was right; setting up an infrastructure that has flexibilty and redundancy is ultimately the way to go. If all the eggs are in the one basket, as has been with Shuttle, then America's space program could be paralysed as it was after Challenger and Columbia. But if the eventual CEV design chosen is not a heavy, integrated Mothership/Lander, it would be the ideal to have the CEV able to be launched on Atlas V, Delta 4 or SDV, so if there were an accident with one vehicle, while the investigation was conducted the "show could go on" with alternative launchers. I strongly suggest a standardised escape system which surely would be the main pre-requisite for man-rating, as would be error detection sensors and redundant systems. I'm not sure if developing seperate "Motherships" and landers are the way to go. During an Apollo 13 abort situation, yes, but otherwise developing two vehicles is very costly and a Moon-only lander would be useless la <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

mattblack · Mar 31, 2005

The blunt-biconic ship. <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

smradoch · Mar 31, 2005

What about transporting crew to the lunar base with something like this for 3 persons? It would be equaly safe (maybe safer), very cheap to develop and easily attached to CEV. Landing (3 or four hours) from LLO to lunar surface will be EVA.

najab · Mar 31, 2005

Hmm... great picture, I'd love to see it get built.

smradoch · Mar 31, 2005

mattblack This blunt-biconic ship seems to be quite heavy, nonmodular (more for Moon than Mars - not both) and would have difficulties with shielding at Moon. The diameter seems to be quite big (more than 5m), suitable for really heavy launcher. I suppose, that probability of building superheavy launcher in 20 years is very low so .... Do you have any link to that?

mattblack · Mar 31, 2005

Interesting articles: http://www.spacecongress.org/2004/Panel-4/2Collins.pdf http://www.spacedaily.com/news/oped-05za.html http://www.ssdl.gatech.edu/main/ssdl_paper_archive/aiaa_2004-3735_paper.pdf http://www.thespacereview.com/article/208/1 http://www.orbit6.com/rockets/shc_tom.htm http://www.space.com/spacenews/businessmonday_040412.html <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

mattblack · Apr 1, 2005

bump. <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

smradoch · Apr 1, 2005

Great links, thanks. I already knew some, but still thanks. About Centurion, Shuttle C and Ares: I still think that next heavy launcher should be human rated (possible piloted or cargo missions) with very low development costs and easily upgradeable. I'm aware of development costs for Centurion and human rating for Shuttle C. From this point of view Ares seems good. But as I said I would begin with somethink smaler (80t) and cheaper using maximum of STS infrastructure. For expendable vehicle 3 SSME engines are not a good option (maybe less of them? or 2 RS-68 with bigger expansion).

mattblack · Apr 1, 2005

Using 3x SSME and the conventional 4-segment SRBs would get your man-rating straight away. But 2x RS-68s and 5-segment boosters would need to go through the man-rating procedures. But to me, the added performance of the 5-segment SRBs and the reduced cost of the "throwaway" RS-68s would be worth it. And there still wouldn't be any need to change the VAB, Crawlers or the launchpads even with this config. Brilliant! <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

smradoch · Apr 1, 2005

I think that man-rating is not problem of engines, but problem of design approach and reliability. RS-68 is more reliable than SSME from design. SRB human-rating is in safety (wall thickness, system backups etc.) Whole rocket has to have means to protect crew in case of a failure and it would be difficult for side-mounted SDV (Shuttle C or STS). That is why I prefare inline launchers which would be able to launch crew only or cargo only in approx. same basic configuration.

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