Shuttle C - Bigger, better, badder

Mark S · 2002-11-09 20:18:12

Our ability to launch anything to the Moon, Mars, or outer planets is limited by the 24 tonne limit of existing boosters (Shuttle, Titan IV, Delta IV.) On this forum we have established that resurrecting the Saturn V or Energia is possible but not practical due to the presence of shuttle technologies that will help us build something bigger.

Zubrin's Ares is an outgrowth of previous Martin studies for Shuttle-C, an unmanned cargo rocket using shuttle boosters and ET for the 0th and first stages. Ares carries its payload on an upper stage, although the official Shuttle-C studies carried it in a lateral payload canister which housed the engines.

According to David Portree's Romance to Reality, Martin actually planned to use Shuttle-C to make an "EELV," like the Delta IV heavy. Three ETs with attached angines would be mated side to side with an upper stage on top. Six advanced SRBs would give the ET booster some help off the ground.

Today we have the tools to make it all possible. The RS-68 is cheaper and provides more thrust than the SSME. The Shuttle ET is lighter. The French Vulcain 2 engine is the perfect size for the upper stage of the Shuttle-C rocket. Fabricating extra ETs and SRBs for the Shuttle C will also bring down launch costs for the standard Shuttle.

It's time we go ahead with Shuttle C. If only NASA had the guts to commit to a manned Mars mission.

nebob2 · 2002-11-09 20:44:15

Looking back at the designs proposed in NASA's DRM 1.0, one may fit you need and be less complicated. I like the option which uses a central booster based of a STS tank with three SSME's and seven strap on boosters with one RD-170 engine each. The upper stage would use one SSME. The design would lift 209 tonnes to a 220 n.mi. circular orbit. Replace the SSME's with RS-68's and the liquid boosters could be replaced with SRB if wished, although the liquid boosters would have their advantages. This will be more than enough to support a manned presence in Space and would use a mininum of new materials.

Mark S · 2002-11-09 21:52:29

I don't like SRB's either because they limit your abort modes (although a launch abort is moot when dealing with unmanned cargo rockets.) Using Zenit first stages (similar to the Energia strap-ons) would make a lot of sense, even though it would take longer to test opposed to the proven SRB/ET combination.

As I've indicated before, I like launch systems that can be expanded to meet the needs of the payload, just like the Delta IV and Atlas V. Your Shuttle-C would be good for launching a Mars Direct style mission. Adding the two ETs side-by-side would enable even larger payloads to be sent to Mars.

RobertDyck · 2002-11-10 01:07:02

I argued for a much simpler configuration because it would have a very low development cost.

I had originally argued for using the Energia launch vehicle because all infrastructure was in place, and the Energia strap-on boosters were just a Zenit first stage with a gimbal that has just 1 degree of freedom. Since RD-120 engines were in storage, all the Energia would require was restoration of production of the core module; equivalent to the ET. Another member here pointed out the safety certification of the RD-120 engines expired in 1997, but a thorough overhaul should permit them to be used. Then the vehicle assembly building collapsed. I'm not sure, but I think the RD-120 engines were stored there.

NASA now likes to talk about the Magnum. It is also a Shuttle derived vehicle, but it is a totally new design. Launch requirements are not compatible with Shuttle, so it would require new launch facilities. All this is expensive.

Robert Zubrin's Ares was designed to match the Mobile Launch Platform used for Shuttle, so it could use existing launch facilities. The external tank does not have the tear-drop top so that requires some new tooling at the factory.

Using Zenit boosters to replace SRBs does increase safety, however existing engineering is designed for the mass and thrust of an SRB, so that again means the expense of developing a new vehicle. Such a launch vehicle would also require at least a new MLP. A vehicle that uses 2 or 3 ETs, would not be compatible with existing launch pads at all. Changing engines to RS-68 or Vulcain would again require extensive engineering to develop a totally new vehicle.

For a cost and project management point of view, I argue for Shuttle-C itself rather than some other Shuttle derived vehicle. That means 2 SRBs, one external tank as it is flown on the Space Shuttle, 3 SSMEs, and 2 OMS pods. It would include all the existing fuel pumps, helium tanks, gimbals, hydraulics and auxiliary power units to support the Space Shuttle Main Engines. The thrust support structure (frame) would require very little modification from the current one. If you make the engine pod recoverable, it fits with the internal politics of NASA while providing the same reusability as the current Space Shuttle.

Getting into details, an expendable fairing would require a little structural support to prevent the engine pod from twisting on its attachment to the ET. Currently the structure of the Shuttle's cargo bay provides that torsional support. I calculated the landing mass of the engine pod to be about 14.4 tonnes and X-38 masses 11.3 tonnes, so the parafoil would have to be slightly enlarged. The onboard computer would be an off-the-shelf single board computer. Launch software would be adapted from existing Shuttle Orbiter software; while landing software would be adapted from X-38. The reaction control thrusters would be new and much smaller since they would just control re-entry of the engine pod. Notice the new stuff is just small stuff. That is one of the key points to keeping project cost down: the larger the component is the less modification you make. This design would use the exact same assembly and launch facilities, exact same launch mass, exact same thrust, exact same torsion, exact same acceleration profile, exact same orbital dynamics. Manoeuvring once inserted into orbit would be different due to different RCS thrusters, but operation of the OMS would be the same. In fact, I would use the smaller RCS thrusters only for de-orbiting the engine pod. On orbit manoeuvring of the payload I would leave to the payload itself, or rendezvous with a Shuttle Orbiter. The fairing would be jettisoned after the ET due to the structural attachment to the ET. X-38 uses landing skids instead of inflatable tires since they are so much simpler and, therefore, more reliable. I would use the same thing, but ensure there are shock absorbers to cushion the impact of landing. That only leaves the heat shield. Some people would argue for a lifting body and silica heat shield tiles like the Shuttle Orbiter, or use of the new metallic tiles, but I argue that an ablative heat shield that can be easily replaced would have a lower per-launch cost than maintenance of the tiles. An ablative heat shield permits a simpler and lower mass airframe. The airframe would not be a cone-shaped capsule like Apollo, but flat sides with the same fibreglass blankets as the white areas on the Shuttle Orbiter. That also eliminates the flap/airbrake beneath the Shuttle Orbiter's main engines.

So what does this require? It uses all the same guts as the Space Shuttle Orbiter's engine compartment. It is just a new airframe, small enough to fit on a truck, and a new fairing. It would use all the same launch, manufacturing and maintenance facilities as the current Shuttle. The only new landing equipment would be a flatbed medium truck with dual rear axle and a truck crane. This design uses the KISS principle: Keep It Simple Stupid.

RobertDyck · 2002-11-10 01:40:58

You are saying that ISS is orbiting at 220 Nautical miles, not 220 Statute miles. The NASA web site said simply 220 miles. That makes a world of difference. 220 nautical miles translates to 407km, while 220 statute miles translates to 354km. That explains why Shuttle and Ariane 5 have published lift capacity to 407km altitude. I had argued earlier that Shuttle-C using the configuration I just described would have a lift capacity of 91.9 tonnes to that altitude, while Shuttle Orbiter has 16.05 tonne lift. That makes the difference even more dramatic. Now I understand why Mars Climate Orbiter had its metic conversion error.

nebob2 · 2002-11-10 02:05:21

I would argue that there could be a need for the origonal Shuttle-C and a STS derived HLLV. Shuttle-C would be excellent for more cheeply placing cargo in LEO, but its limited capacity (91t vs 209t) and nerrow diameter of the cargo pod would make a HLLV capible of using the same launch facilities a useful asset.

I just courious, what makes the Magnum incompatible with current launch facilities? It has a ET based core and shuttle boosters just like Ares. Is it the placement of the engines on the core?

RobertDyck · 2002-11-10 03:44:29

Yes, exactly. The Mobile Launch Platform has 3 holes cut in it for exhaust: 2 for the SRBs and 1 for the main engines. The holes for the SRBs also have clamps designed to support the weight of the SRBs and hold them down durring main engine ignition. The MLP also has wing supports for the Orbiter. Magnum places the engines under the ET, where the MLP does not have a hole. Ares places its engine pod at the same location as the Shuttle Orbiters main engines. Considering the weight of a HLLV, you can't just cut another hole. Moving the engine location means a whole new MLP.

Mark S · 2002-11-10 11:39:44

The shuttle MLP was actually modified from the Saturn V MLP, which had a completely different engine configuration from the shuttle. I don't think it would be too impractical to modify one of the two MLP's for a shuttle-derived booster.

I also think that we should move away from reliance on the MLP. The Energia transporter system allowed for faster transport (by a launchpad on rails) to the launch site, and the booster was transported in a horizontal fashion, which is easier from a mating, boarding, and checkout standpoint.

I don't see too much of a problem modifying the Shuttle ET for an upper stage. Instead of using the ogive LOX tank on the original ET, just use a shortened hydrogen tank, with common hemisphere bulkheads from the ET hydrogen tank.

Side-mounting the engines may have some benefits, even if the MLP is modified or discarded. It allows for an aft cargo container (ACC) on the end of the ET, and the ACC can hold equipment and stores for modifying the ET into a habitable module.

RobertDyck · 2002-11-11 00:03:29

I believe there are 3 MLPs, all of which are a modified Mobile Launcher from Saturn V. The mobile service structure from 2 of the Saturn V Mobile Launchers was used as material for the static service structure currently at the launch pads. The third one is cut into pieces and rusting in a field; NASA thinks they might rebuild it as a museum piece. I believe there are 2 doors from the vehicle assembly building, 2 launch pads, 2 crawlers, but 3 MLPs. However, all MLPs are in use to fill the launch schedule. I doubt they would let you permanently take one out of service to support a shuttle derived launch vehicle. A new one would have to be built.

The current congress budget watch-dogs are paranoid that any attempt to send a manned mission to Mars would result in the same $450 billion price tag as the 90-day report. To alleviate their fears you must first start by being completely forthright. Do not try to hide development cost for manned mission equipment in other programs. I talked to a NASA contractor who still tries hiding development cost in other programs; that just perpetuates congressional fear. The second step to making a manned mission happen is to drastically reduce the cost. The third step is to ensure all development work is on time and on budget. Any further cost overruns will again raise the fear that the final price tag will be $450 billion. After the cost overruns of ISS, congress is deep in shock.

This is why I am almost obsessed with cost reductions. Yes, a horizontal transporter like the Russian Energia has a lot of merit. It requires additional engineering to ensure the rocket doesn't fall apart when it's on its side, but it can be done. A new MLP could be built for any engine placement configuration. All new equipment costs money, and remember that anything designed to service a shuttle-sized vehicle or HLLV will be gigantic.

The vehicle itself could also be modified to improve it, but that again costs money. A shortened ET with common bulkhead between oxygen and hydrogen tanks could be propelled into orbit with a small strap-on booster. If you put a hatch in the common bulkhead and a hatch at the peak of the oxygen tank and bottom of the hydrogen tank, then it could be used as a module for a space station. A docking tunnel and all internal fittings could be placed in an aft cargo container, as you suggest, or carried in the cargo bay. That does raise the question of whether the insulation is sufficiently durable for space. An outer blanket could be added which is suitable for space. That adds additional weight and additional cost. Every change adds additional cost. That's why I argued for the configuration in message 4: it has the minimum change required to provide a cost effective HLLV.

I would suggest using the minimum-change Shuttle-C as an immediate HLLV. For the long term, I would argue for development of SCRAM jet technology, and further developing that into an engine that can smoothly transition between RAM jet operation, SCRAM jet, air augmented rocket, and Liquid Oxygen fed rocket. Such a multi-mode engine is called a Rocket Based Combined-Cycle engine, or RBCC. Boeing is working on an RBCC. The September-October issue of the Journal of Propulsion and Power has several papers on SCRAM jet engines intended to operate in the Mach 4-6.5 range.

Mark S · 2002-11-11 10:10:13

For the long term, I would argue for development of SCRAM jet technology, and further developing that into an engine that can smoothly transition between RAM jet operation, SCRAM jet, air augmented rocket, and Liquid Oxygen fed rocket. Such a multi-mode engine is called a Rocket Based Combined-Cycle engine, or RBCC. Boeing is working on an RBCC. The September-October issue of the Journal of Propulsion and Power has several papers on SCRAM jet engines intended to operate in the Mach 4-6.5 range.

Funny that you should mention scramjets and RBCCs.

I have some hope that air-breathing engines will drastically reduce the cost of space. However, Rand Simberg, my personal hero, seems to think that the depressed trajectories of air-breathing spaceplanes negate the benefits of not carrying an oxidizer.

With that being said, developing an RBCC should still be a priority. Even if they aren't good for spaceplanes, they would still be useful in Mach 6 bombers and "Orient Express" airliners.

Mark S · 2002-11-14 15:17:18

I'm starting to to favor the Shuttle C over Ares for the Mars rocket. On problem with Ares has to do with the current ET: it's not designed for the bending momnets created by a payload mounted on top of the vehicle. Some strengthening will probably be required.

Crossman · 2002-11-27 10:27:19

Hi people,

I find this discussion interesting, however since NASA is not developing anything in this area perhaps we should consider changes in the shuttle-C/Ares baseline.
1. Switch to methane as the primary fuel (7X as dense as hydrogen), meaning smaller lighter, easier to manufacture tankage.
2. Use hybride solid/liquid rockets in place of SRB's.(safer to use and to fuel, can be sut-down and throttled, simpler than liquid fueled engine like those of the Zenit)
Yes I know the prevalent philosophy is to use so called off the shelf, equipment, but is it really all that much cheaper this stuff IS AFTER ALL MADE FOR NASA hardly cheap. Private companies have developed engines etc.

Just some thoughts,
Crossman

.

Mark S · 2002-12-01 13:17:16

An all-new booster might be the way to go, especially if you can build a modular heavy-lifter (in the spirit of Delta IV and Atlas V.) But doing so requires research and development money that just doesn't exist right now. The scarcity of funds keeps Shuttle-C in contention to be the Mars rocket of choice, and that will not change for a while (on the bright side, a large portion of NASA's R&D is being spent on nuclear propulsion.)

robcwillis · 2003-01-05 12:39:59

Please see response to "Shuttle C" in the Launch Vehicles stream.

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#1 2002-11-09 20:18:12

Re: Shuttle C - Bigger, better, badder

#2 2002-11-09 20:44:15

Re: Shuttle C - Bigger, better, badder

#3 2002-11-09 21:52:29

Re: Shuttle C - Bigger, better, badder

#4 2002-11-10 01:07:02

Re: Shuttle C - Bigger, better, badder

#5 2002-11-10 01:40:58

Re: Shuttle C - Bigger, better, badder

#6 2002-11-10 02:05:21

Re: Shuttle C - Bigger, better, badder

#7 2002-11-10 03:44:29

Re: Shuttle C - Bigger, better, badder

#8 2002-11-10 11:39:44

Re: Shuttle C - Bigger, better, badder

#9 2002-11-11 00:03:29

Re: Shuttle C - Bigger, better, badder

#10 2002-11-11 10:10:13

Re: Shuttle C - Bigger, better, badder

#11 2002-11-14 15:17:18

Re: Shuttle C - Bigger, better, badder

#12 2002-11-27 10:27:19

Re: Shuttle C - Bigger, better, badder

#13 2002-12-01 13:17:16

Re: Shuttle C - Bigger, better, badder

#14 2003-01-05 12:39:59

Re: Shuttle C - Bigger, better, badder

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