Redesign the STS

[skyone]

I would have built a vehicle more akin to Chrysler's SERV, a dandy concept unfortunately discarded during phase A/B studies.<br />http://www.astronautix.com/lvs/shueserv.htm<br />http://www.abo.fi/~mlindroo/SpaceLVs/Slides/sld034.htm<br />SSTO, flexible, voluptuously beautiful<br />Go onion go!

 

[rocketman5000]

Does resemble an onion. It would be able to have appreciable aerodynamic drag at every high altitudes. I also like the fact that you don't need to cover the whole vehicle with TPS like most lifting bodies

 

[erikm]

Hmm. An interesting challenge <img src="/images/icons/laugh.gif" /><br /><br />For the first part I'll assume I'm working on something of a budget.<br />I'd retire the orbiter and move to a Shuttle-C setup. The engines would be in a re-entry pod faired into the cargo carrier on the way up. In orbit the engine pod would either be auto-ejected from the cargo carrier or be unbolted by hand at a ISS. <br /><br />Personally, I tend to agree with the people who favor splitting cargo and personnel. However, if I were forced to carry people up on this, there are a couple of different ways to go about it. In both cases there should be enough room lengthwise to allow for an engine pod, the passenger pod and something the size (and weight) of an ESA Autonomous Transfer Vehicle, hopefully with enough of a weight budget left over to haul the main tank into orbit.<br /><br />For the first method I would choose a minishuttle like the Kliper, encased in the cargo carrier. The minishuttle would have a ring of solid rockets around its rear to function as a re-entry pack (fired sequentially) or escape system (fired simultaneously). The minishuttle would have an autonomous life support endurance of one week at most.<br /><br />A second and odder method would be to parallel-mount two complete Soyuz craft inside the cargo carrier fairing. There might not be a launch escape system (unless it pulled part of the cargo carrier fairing off as well) but the spacecraft could operate on separate missions. One could head to ISS with the ATV while the other could go fetch Hubble, for instance. <br /><br />The main tank and SRBs I would could live with essentially leaving unchanged except for specific missions. A tank going up to orbit might, for instance, have the beginnings of a wet-lab built in.<br /><br />Of course, there are more extreme options. Reading Gary Hudson's 'http://www.spacefuture.com/archi</safety_wrapper

 

[gunsandrockets]

If I had to redesign the STS, but keep core features such as the SSME and vertical takeoff and horizontal landing, the old Lockheed Starclipper isn't a bad jumping off point...<br /><br />http://www.astronautix.com/lvs/stalight.htm<br /><br />In my opinion the most important differences are the smaller orbiter (only 11 tonnes payload), 1-1/2 stage configuration (no SRB) and different Thermal Protection System (no tiles). Here is the stage data...<br /><br />Stage Data - Starclipper<br /><br />* Stage Number: 0. 1 x Starlifter Tank Gross Mass: 257,778 kg. Empty Mass: 12,971 kg. Thrust (vac): 0.000 kgf. Isp: 455 sec. Burn time: 209 sec. Isp(sl): 355 sec. Diameter: 8.00 m. Span: 8.00 m. Length: 25.00 m. Propellants: Lox/LH2 No Engines: 0. None Status: Study 1968. <br /><br />* Stage Number: 1. 1 x Starlifter Gross Mass: 42,630 kg. Empty Mass: 19,955 kg. Thrust (vac): 532,000 kgf. Isp: 455 sec. Burn time: 228 sec. Isp(sl): 355 sec. Diameter: 15.85 m. Span: 15.85 m. Length: 25.00 m. Propellants: Lox/LH2 No Engines: 3. SSME Status: Study 1968.<br /><br />The TPS is described as using hot body structure instead of fragile silica tiles "The Starclipper's passively cooled re-radiative-insulative structure was designed for 10-100 reuses and easy maintenance and replacement." So the Starclipper's TPS resembled the structure of the forebody of the Gemini capsule rather than the tiled Space Shuttle.<br /><br />But here is where I add my own weird idea. What if instead of dropping the fuel tank short of orbit, it is carried all the way up? I'm thinking since the tank is going to be disposed of in any case and since the tank will also be insulated to keep the LH2/LOX from boiling off before launch, why not also use the drop tank as a disposable heat shield during reentry? Think of it as a rigid pre-inflated ballute!<br /><br />So my idea is to change the StarClippers triangular tank to a more Shuttle like arrangement, ca

 

[rubicondsrv]

the starclipper dropped the tanks on ascent. <div class="Discussion_UserSignature"> </div>

 

[gunsandrockets]

"the starclipper dropped the tanks on ascent. "<br /><br />And your point is...?

 

[soccerguy789]

I believe that, had we made use of the shutle tanks in orbit, and the air force had backed the shuttle as they prommissed, it would have been everything they said it would. My redisigened shuttle plan involves small docking ports at both ends of the fuel tank, and a small space for conversion gear. make the ET more space station friendly, and haul the boosters (4 smaller ones as opposed to 2 ****** ones) to orbit where they could be either used as station components or loaded into the orbiters cargo hold for return, the orbiter itself would have small jet engines for assist during landing.

 

[mlorrey]

Yeah, hauling the SRBs to orbit is a dumb idea. The ET at least can be gotten to orbit at zero payload cost.<br /><br />Dump the shuttle, dump the SRBs, build two return pods:<br />1) for five SSMEs in a ring which will drop off at 65-70% of fuel mass burned. This will reenter without need of TPS and parachute to ocean recovery.<br />2) for the sixth center SSME sustainer motor, which will power the tank and cargo to orbit. This pod detaches in orbit and reenters with a MOOSE type reentry system.<br /><br />This will place an empty tank and up to 100,000 lb of payload and conversion equipment in orbit, with a RCS.

 

[mlorrey]

The Russian company Molniya has built such liquid boosters with swing-out wings for airport landings.

 

[mlorrey]

It may have been a mock-up, but I have seen hardware on the ground with real photos...

 

[j05h]

>Yes, they were mockups.<br /><br />That would be the "Baikal" flyback booster. I'd like to see that actually fly. The mockups were shown at the Paris Air Show, IIRC. <br /><br />The "shuttle" is being redesigned: major components are finding their way into the CLV & SDHLV. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[mlorrey]

Eh, that is of questionable use, except at hypersonic velocities. Spliterons are effective based on the distance from the CG, which isn't much on supersonic vehicles. The B-2 gets away with it cause it has such a huge wingspan.

 

[micro10]

We can speculate about the tank foam problem till the cows come home..But in this case it's just going to take some time to do some research in trying different applications and engineering results to fix the problem..Just let them keep working on it.."There is a fix"and it will not come by getting in a hurry. Maybe the can get a dupont enginneer to work on a new formula paint mix on certain parts of external tank that would be a better application then foam spray..Sometimes a paint mix that don't set up as hard can prove to be a better insulation cover all...

 

[scottb50]

The B-2 gets away with it because it has such a huge wingspan....<br /><br />It could be any size, as long as the cg is within limits. it will fly. Actually the bigger the better for a re-entry vehicle.<br /><br /><br /><br />Thats why an B-2/X-33 mutation, might be a possibility. <br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[rocketman5000]

doubtable. when reentering the atmosphere aerodynamic control through control surfaces is like skating on ice with dull skates. there isn't a lot of air up there to provide any yaw damping at all. Therefore it would take a long time to react and a long time to stop the yawing as well. If you have ever seen a B-2 fly it makes very slowly at shallow bank angles. Probably not all that suitable when trying to keep your vehicle pointed in such a manner that the shockwave angles don't become to extreme on any surface

 

[mlorrey]

The problem with the Shuttles vertical stab is that it is in the wake of the shuttle, so of course its not going to provide much lateral stability at all during reentry. Wingtip staberons would start to provide lateral control as soon as the indicated airspeed goes above 100 knots, which should be at around 300k-320k feet.

 

[scottb50]

The larger the mass of the vehicle the more it slows when affected by atmosphere and the more surface there is to dissapate the heat.<br /><br />By the time you are using aerodynamic controls you are well through the heating. That's why the thrusters on Columbia flew it until they lost propellant or operational control.<br /><br />A big, flat smooth surface will create a lot of drag and slow better. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

I beg to differ. I've done reentries of vehicles without any RCS in X-Plane, and unless the simulator is unrealistic, control surfaces do start working once your indicated airspeed is at or above your vehicles standard stall speed. Indicated airspeed is, of course, a measure of both the velocity of the surrounding medium, and the pressure of it, which is why you can be travelling at 70k ft at mach 3 and have an IAS that is subsonic. I've flown sims to orbit, reaching mach 24, while never having an IAS above 375 kt.<br /><br />The sts orbiters vertical stab is useless only because it is in its own wake on reentry. Wingtip staberons would provide lateral control almost from the start, but would need to be built as sturdily as the rest of the wing. This is why the Dynasoar was designed with staberons and no center vertical stab. <br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>The larger the mass of the vehicle the more it slows when affected by atmosphere and the more surface there is to dissapate the heat. <br /><p><hr /></p></p></blockquote><br /><br />This is even more absurd. The larger the mass of the vehicle vs its surface area (vehicle density, essentially), the less it slows until it is deeper in the atmosphere, and it will require more extreme TPS. A light vehicle with a lot of surface area slows faster because it is less dense and thus loses momentum faster in thinner atmosphere.

 

[scottb50]

I beg to differ...<br /><br />All I said was they are not used during the high heating areas, I don't know exactly when they become active, but I bet it's a lot lower than that. <br /><br />I can't imagine a simulation of something impossible to do would not be life like.<br /><br /><br />This is even more absurd...<br /><br />Maybe I wasn't overly clear, what I meant was the physical size. What I was trying to say is the same thing you did a whole lot clearer. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Perhaps you misspoke. When you say a vehicle has more mass, that does not mean it is physically bigger in size. A 5 meter iron meteor has a lot more mass than the STS Orbiter, but has a whole lot less cross sectional area, which is why the meteor comes in hot and heavy and doesn't lose much velocity til it is pretty low (about 150k feet). The Shuttle starts losing velocity about 200-250k, while a low wing loading vehicle, like the X-33, is meant to have lots of empty space, so the cross sectional loading in lbs/ft^2 is much lower. This causes it to slow faster at high altitude and because the dynamic pressure is lower over the entire surface, it heats up less.<br /><br />The STS Orbiter has a range of wing loading of 95.6 lb/ft^2 to as much as 120. X-33 wing loading was expected to be approximately 30 lbs/ft^2. My X-106 design will be 18-19 lb/ft^2. The differences in this are striking. While both the STS Orbiter and the X-33 were expected to reenter at a 40 degree AOA, the Orbiter holds this AOA until 200kft, but has only shed about 30% of velocity. It is clear that much of its early trajectory it holds significant amounts of momentum due to its high cross sectional density.