How would you improve the Shuttle design?

[Nibb31]

I would change the shuttle so that it only had OMS engines, and was launched by a main rocket core with four liquid fuelled boosters, which would give it a max payload to orbit of 50 Tonnes, over the Shuttles original 30. (Yes. I know I have just exactly described the Buran. That was kind of the point.)

The whole point of a Space Shuttle was to bring back and reuse the most expensive part of the launcher: the engines. If you are launching a complete airframe just to bring back the same airframe, and throwing away a huge rocket to do so, then what's the point of launching that airframe in the first place? Wings, hydraulics, landing gear, and tiles serve no purpose in space. You're better off throwing away a smaller/cheaper rocket and bringing back the meatbags in a smaller/cheaper capsule.

Buran didn't make sense economically. It's only purpose was for the USSR to have a Shuttle because the US had one. The Soviets knew that it didn't make sense, but they also also knew that the US STS didn't make sense either. Consequently, they figured that the STS must have had a secret military purpose, so they concluded that needed to match it and cancelled the Spiral/MAKS/BOR program which was more promising.

[Nibb31]

When designing a spacecraft, you really have to keep in mind what you're building it for.

- Do you want to launch crew to LEO and bring them back safely? => Soyuz, Dragon, DreamChaser, CST-100...

- Do you want a versatile manned spacecraft for BEO => Apollo, Orion...

- Do you want cheap access to LEO => Ariane 6, Dragon 9-R...

- Do you want a spaceship that looks cool => Space Shuttle

The whole point of building a spacecraft with wings is stupid. You need a massive launcher for all that extra hardware that is only used for the last 10 minutes of the flight.

[magnemoe]

The whole point of a Space Shuttle was to bring back and reuse the most expensive part of the launcher: the engines. If you are launching a complete airframe just to bring back the same airframe, and throwing away a huge rocket to do so, then what's the point of launching that airframe in the first place? Wings, hydraulics, landing gear, and tiles serve no purpose in space. You're better off throwing away a smaller/cheaper rocket and bringing back the meatbags in a smaller/cheaper capsule.

Buran didn't make sense economically. It's only purpose was for the USSR to have a Shuttle because the US had one. The Soviets knew that it didn't make sense, but they also also knew that the US STS didn't make sense either. Consequently, they figured that the STS must have had a secret military purpose, so they concluded that needed to match it and cancelled the Spiral/MAKS/BOR program which was more promising.

An small buran launched with an falcon heavy reusable would make sense.

I might do something totally different, you want crew transport to space station, repair and other eva work away from station.

take an dragon capsule, and make it far longer and a bit wider, keep living space on top, eva module with airlock and suits below, this also work as living space and pressurized cargo space, you need an manipulator arm in this module too below this you have engines and heat shield so yes the bottom will be far larger than the original dragon.

Below the heat shield you have the same disposable stage as the dragon have, this is non pressurized cargo and extra fuel and air.

Operates the same way as the manned dragon but might be an idea to dropp bottom part below the living space if you use the escape tower or you get engine fail during landing.

After first stage separation this is not an option as you also loose your heat shield but in this setting you don't need the huge getaway speed.

You would probably want an version without the manipulator arm too for missions where its not needed.

You could possible expand the bottom part to bring larger modules for installation.

Without dedicated airlock for eva you would have an combined crew and cargo carrier, here you will use all 7 seats in the dragon, for the shuttle replacement you would not need a 7 man crew.

No idea of weights here but it should be significantly lighter than an small shuttle with the same performance and it would be more flexible in payload capacity.

The only thing you lose is the large cargo space for return flights. yes you could rig something out of this design.

[xzxvrx]

A single- piece heat shield would be extremely difficult. I'm not saying that the the thermal tiles are better, i'm just saying that coating the underside in RCC would be worse. With RCC weighing about what, 124lb/cu ft? The entire shuttle would be insanely heavy. Also, RCC is very rigid, and any slight bending will break. When the shuttle is undergoing temperature changes from -180º to 180º, natural flex will be inevitable. If we use ablatives, the re-usability aspect would be entirely pointless. The idea of the shuttle was to have minimal maintenance between flights, needing a new heat shield after each flight completely negates that. There are alternatives to RCC (which i mentioned because it was actually used on the shuttle) but, a huge single peice heat shield? Ok, how long did it take to make the Orion heat shield? And then how big is the Space Shuttle? That would undoubtedly be difficult and more expensive.

[jwenting]

I'd contact Lockheed-Martin to complete VentureStar...

[rkman]

An small buran launched with an falcon heavy reusable would make sense.

The same was said of the Space Shuttle before it actually existed.

[Moar Boosters]

The same was said of the Space Shuttle before it actually existed.

Well the Shuttle might have made more sense if the program it was designed to support had existed.

Originally it was supposed to ferry crew and equipment to a gigantic 100+ man space station. Every mission would have carried a full cargo bay of equipment and supplies and would have exchanged a bunch of crew members. It would have made a bit more sense if we had the kind of permanent space presence NASA predicted.

[DerekL1963]

Well the Shuttle might have made more sense if the program it was designed to support had existed.

Originally it was supposed to ferry crew and equipment to a gigantic 100+ man space station. Every mission would have carried a full cargo bay of equipment and supplies and would have exchanged a bunch of crew members. It would have made a bit more sense if we had the kind of permanent space presence NASA predicted.

Yep. The Shuttle was originally supposed to be the equivalent of a light pickup truck, and along with a Saturn V or Titan III derivative, the cornerstone of significant system space presence and transportation infrastructure. When it became apparent that neither the Administration nor Congress was interested in funding those pipe dreams... the Shuttle began to grow and morph into the large one-size-fits-all vehicle that finally flew. (NASA never really gave up on the idea that they would soon be funded at peak Apollo levels again.) Why? Because they were stuck between a rock and hard spot - the Administration nor Congress mandated that the Shuttle would be built, but refused to properly fund it. (Hence the whole mess with the DoD, even though that affected the design less than urban legend would have you believe as the vehicle was already growing.)

But to be fair, even budget limited (but still very expensive admittedly), they did produce a near miracle... a vehicle that carried and returned more people to space than all others to date combined. For that matter, it's flown more missions than any other vehicle (Soyuz is still ten or fifteen mission behind, and in the end will have taken almost twice as long to accumulate that number, and won't match the number of passengers until sometime around the middle of the century at the current rate). It's safety and reliability is insignificantly different from any other vehicle. It carried out missions that no other vehicle in existence or on the drawing boards could have done. Etc... etc...

And it's being penny wise and pound foolish that's going to kill our space program. Sure, we've gone from SUV costs to bare bones subcompact economy car costs... but we've also gone from SUV capability to bare bones subcompact economy car capability too. Only a fool thinks Dragon or Orion can replace the Shuttle.

[KASASpace]

By my calculations, the 21 tons of OMS fuel being MMH/NTO required 16 cubic meters of storage. To achieve the same deltaV it provided, but using LH2/LOX, due to the higher Isp of the RL10, 13 tons of LOX and 2 tons of LH2 would be needed. However it would require 41 cubic meters of storage, due to the low density of the cryogenic fuels.

Thus the OMS pods would need to be 3 times bigger to house the fuel tanks.

Well, how much D-v did the OMS pods actually give? OH YEAH, less than half a kilometer a second! YAY! So did you calculate that, my friend?

Edited December 16, 2013 by KASASpace
forgot a word

[KASASpace]

When designing a spacecraft, you really have to keep in mind what you're building it for.

- Do you want to launch crew to LEO and bring them back safely? => Soyuz, Dragon, DreamChaser, CST-100...

- Do you want a versatile manned spacecraft for BEO => Apollo, Orion...

- Do you want cheap access to LEO => Ariane 6, Dragon 9-R...

- Do you want a spaceship that looks cool => Space Shuttle

The whole point of building a spacecraft with wings is stupid. You need a massive launcher for all that extra hardware that is only used for the last 10 minutes of the flight.

They only wanted wings for cross-range capability, so that way if they reenter over the ocean they could "glide" to a runway and land on it.

[KASASpace]

The whole point of a Space Shuttle was to bring back and reuse the most expensive part of the launcher: the engines. .

You could still do that easily by adding a seperatable booster segment on the initial launcher that would separate and under automation could fly back to the space center or a runway for refurbishment. Don't have to wait a few days and get a head start on refurbishments.

[Nibb31]

They only wanted wings for cross-range capability, so that way if they reenter over the ocean they could "glide" to a runway and land on it.

Sure, but they only needed to land on a runway because the damn thing had wings. A capsule can re-enter and splashdown or land anywhere.

You could still do that easily by adding a seperatable booster segment on the initial launcher that would separate and under automation could fly back to the space center or a runway for refurbishment. Don't have to wait a few days and get a head start on refurbishments.

Absolutely. But then it would look more like the fully-reusable Falcon upper stage + Dragon concept. No need for wings.

[DerekL1963]

You could still do that easily by adding a seperatable booster segment on the initial launcher that would separate and under automation could fly back to the space center or a runway for refurbishment. Don't have to wait a few days and get a head start on refurbishments.

For certain handwaving-and-smoke-blowing values of "easy", sure. In reality, it would be a complex and heavy vehicle - I.E. expensive. Very, very expensive.

[SFJackBauer]

Well, how much D-v did the OMS pods actually give? OH YEAH, less than half a kilometer a second! YAY! So did you calculate that, my friend?

I don't get the point - surely I did calculate that. The OMS were needed to just small orbit adjustements - and they fullfilled that role. However did you calculate the added mass, drag and complexity of replacing ambient-temperature storable, dense fuel like MMH/NTO with a cryogenic, superlight fuel like LH2/LOX?

Actually, in the numbers I posted there is a flaw, since I doubled the amount of fuel in the OMS. Some sources indicate the amount for one pod, other sources for both pods. After finding some NASA documents I revise my numbers:

Orbiter dry mass (Atlantis) - 78.5t

Payload max - 25t (Chandra X-ray observatory, launched in STS-93, weighed 22t).

OMS Propellant max - 10.8t

At an Isp of 315s this gives a dV of 308 m/s.

The OMS fuel thus required 8m³ of storage (4m³ per pod) which is a more reasonable number given the pods size. Likewise, the amount of LH2/LOX for the same deltaV would require 22m³ of storage, not counting the need to deal with a higher-pressure tank and insulation.

I'd say thats a redesign of the entire shuttle. I never said it couldn't be done, or that it would be better or worse - I'm just pointing out the consequences of the change.

[SFJackBauer]

Sure, but they only needed to land on a runway because the damn thing had wings. A capsule can re-enter and splashdown or land anywhere.

While we can't deny the cross-range requirement influenced in the wings design, the fact that the shuttle used a lifting re-entry and touched down smoothly enabled it to bring back delicate stuff from space. Remember that a third of the shuttle missions were exclusively science-related (before the ISS even existed) and even the missions having a commercial payload, or to resupply the ISS or Mir had a number of scientific experiments also. These were all cargo that were sent and brought back down to Earth in a vehicle that never exceeded 3G during its entire flight, from ascent to re-entry and touchdown.

[3_bit]

We need to change the foam, for one. When the Columbia disaster happened, NASA insisted it was not the foam, even though they had absolutely no evidence. Then, when they shot foam at hundreds of miles per hour at the wing of the shuttle, they found that the foam was what was to blame for the destruction of the shuttle and the loss of her crew.

The bigger problem isn't even the shuttle itself. What we need to stop doing is grounding it whenever it decides to fail on us. There are going to be at least a few thousand more deaths in space that are very much mandatory so that humanity can learn how to safely travel in space. For example, if a 747 had an engine failure and crashed today, you wouldn't see air traffic controllers scrambling to get every 747 around the world out of the air. The same should apply to NASA.

For example, back when there were a lot more test flights, you had more than a 30% chance of not coming back from such a flight. But a lot of those deaths were necessary. For example, we learned that (if I recall correctly) a sonic boom forms at the edge of your horizontal stabilizer and works its way back to your ailerons. Lessons like this are ones that have to be learned, and can only be learned by taking risks.

Safety is not an option, especially in space. Back in 1492 Columbus knew he took a big risk when he went searching West. Pioneers like him, knowing full well that they're likely to not come back, are what we need in space. People like him, specifically in the daring aspect, truly have the "right stuff"

[Themohawkninja]

It's hard to say how to improve it.

Clearly some better foam would be a plus, but I think the real issue is not letting a self-fixing problem go unchecked (yes, I am talking about the o-ring). For those of you that don't know, the o-ring on the SRBs failed nearly every time, but since it melted and therefore sealed the would-be leak, NASA decided not to toy with it, since it wasn't creating any problems. Then Challenger happened (or was it Columbia, I always get them confused).

Aside from that, some ejection pods would be nice. By ejection pods, I mean some sort of system in the seats whereby upon critical failure of the Shuttle (or manually if need be) a sturdy air-tight shell would envelope the person sitting in the seat, allowing that person to safely survive the thin atmosphere and parachute to the ground.

[KASASpace]

I don't get the point - surely I did calculate that. The OMS were needed to just small orbit adjustements - and they fullfilled that role. However did you calculate the added mass, drag and complexity of replacing ambient-temperature storable, dense fuel like MMH/NTO with a cryogenic, superlight fuel like LH2/LOX?

Actually, in the numbers I posted there is a flaw, since I doubled the amount of fuel in the OMS. Some sources indicate the amount for one pod, other sources for both pods. After finding some NASA documents I revise my numbers:

Orbiter dry mass (Atlantis) - 78.5t

Payload max - 25t (Chandra X-ray observatory, launched in STS-93, weighed 22t).

OMS Propellant max - 10.8t

At an Isp of 315s this gives a dV of 308 m/s.

The OMS fuel thus required 8m³ of storage (4m³ per pod) which is a more reasonable number given the pods size. Likewise, the amount of LH2/LOX for the same deltaV would require 22m³ of storage, not counting the need to deal with a higher-pressure tank and insulation.

I'd say thats a redesign of the entire shuttle. I never said it couldn't be done, or that it would be better or worse - I'm just pointing out the consequences of the change.

Well, that said, the actual tanks would be smaller than the orbiter fuel pods themselves. You see, 22 ft³ is basically a three dimensional area that is less than 5ft by 5ft by 5ft. So, yeah. I did say composites, too. Think about it.

[KASASpace]

Well until the tech catches up with the ideas, then don't make one. Basically the current systems are noise converters. They take a fuel and make a lot of noise. Besides what the heck is in space that would make you spend a lot of money to go and see? News flash, this solar system is vacant save for Earth. Nothing to see here, move along.....

Have you played KSP? Do you use the LV-N? No? Well, then, shut up.

[KASASpace]

I wish I only knew the entire quote, but it was Michael Collins.

"exploration is an imperative"

As humans, it IS OUR VERY NATURE TO EXPLORE. OUR NATURE TO TRY AND UNDERSTAND, IT IS OUR NATURE TO ATTEMPT THE IMPOSSIBLE, TO ACCEPT RISKS, TOW WORK TOGETHER. Congress is a con to all of humanity, we need some progress, and quick!

[SFJackBauer]

Well, that said, the actual tanks would be smaller than the orbiter fuel pods themselves. You see, 22 ft³ is basically a three dimensional area that is less than 5ft by 5ft by 5ft. So, yeah. I did say composites, too. Think about it.

Its 22m³. The "m" stands for meters

[KASASpace]

Or maybe mass produced reusable engines being used on not reusable fuel tanks! BALLOONS! I'm crazy, get over it! BALLOONS!

Disposable launchers waste resources, adn think outside the box, composite tanks have been done, balloon tanks ahve been done. THe only thing the Atlas booster used in the 60s needed for SSTO was an Aerospike. There, I said it. It doesn't have to be reusable, but an SSTO could be cheaper all the less. An aerospike can operate at all levels of atmosphere and have very little Isp losses, ideal for SSTOs. The Atlas got rid of the booster engines cause of weight and the wrong nozzle shape. EASY AS CAKE! But no gov has figured this out yet.

[KASASpace]

I revise my opinion a little bit. Use composites, a better TPS, and aerospikes on the Orbiter. Make the wings smaller, make the whole thing smaller than it was, stupid USAF backing down last second! Build fleet with decent turnarounds due to better TPS and simpler construction method. Make 20 to 30 launches in a year. Boo-yah. And also use a more common fuel, probably RP-1 or Ethyl Alcohol, in conjunction with LRBs.

Launch Profile:

1. Takeoff

2. Max q, SSME throttle down

3. Throttle up

4. Booster sep

5. MECO

6. OMS orbital insertion

7. Whatever the mission is....

8. return

[DerekL1963]

I wish I only knew the entire quote, but it was Michael Collins.

"exploration is an imperative"

As humans, it IS OUR VERY NATURE TO EXPLORE. OUR NATURE TO TRY AND UNDERSTAND, IT IS OUR NATURE TO ATTEMPT THE IMPOSSIBLE, TO ACCEPT RISKS, TOW WORK TOGETHER. Congress is a con to all of humanity, we need some progress, and quick!

That's just the thing... It's not human nature to explore, at least not amongst the majority of humanity. Yeah, there's a few that do those things, all all important racial yeast... but very few.

I revise my opinion a little bit. Use composites, a better TPS, and aerospikes on the Orbiter. Make the wings smaller, make the whole thing smaller than it was, stupid USAF backing down last second!

The Shuttle was growing even before the USAF got involved - because if it didn't grow, it didn't have a mission since the space station had been cancelled. That's one of the big reasons why the program became so expensive and NASA sought USAF participation in the first place. And that's a huge conceptual error that runs through this thread, you can't improve the design until you know what you're improving it *for*. First, you define the missions, then you define the capabilities needed to carry out those missions, then and only then can you specify the requirements your vehicle will need to meet.

[Jim DiGriz]

Moar struts?