How would you improve the Shuttle design?

[RadHazard]

I like the idea presented in this story. I'm pretty sure the Project NAILSPIKE part is total bunk, but the shuttle tweaks mentioned sounded pretty convincing. As I'm not a rocket scientist myself, I can't vouch for the accuracy of the science, but if it's anywhere close to correct it sounds great (if you don't mind a little hazardous exhaust )

“Take the space shuttle,†he said wistfully. “With just two tweaks, we could have put a hundred tons into its payload bay!â€Â

...

“All right. First, the solid rocket boosters. ... We could make them about twenty percent more efficient if we just replaced the aluminum with powdered beryllium. It’s a lighter atom and the redox reaction is more energeticâ€â€Ã¢â‚¬Â

...

“If you replace the oxidizer in the space shuttle main engines with liquid fluorine, you could also get an extra twenty percent out of them. And I know what you’re going to say next: wouldn’t that give rise to an exhaust plume of extremely hot hydrofluoric acid? You’re absolutely right: it would! But hydrofluoric acid reacts with beryllium oxide to give you beryllium fluorideâ€â€which is almost inert in comparisonâ€â€and hydrochloric acid, which is neither here nor there.â€Â

[Skyrunner27]

I have thought about this for awhile and I have come to a conclusion on what I would do...

-Separate the launch system from the Orbiter in development.

-Continue construction of orbiters and retire orbiters in a orderly fashion.

-Continually improve development.

-Provide some method to break the crew section away from the rest of the orbiter.(In Columbia and Challenger the crew cabin survived most of the accident.)

-Put parachutes into the crew section

-Put more abort options into Rentry and Launch

-Scrap the SRBs for LRBs

-Implement the Shuttle-C

-Extend life time in space.(Seriously the vehicle with the largest living space and largest crew capacity stayed in space for the shortest time.)

[Hailstorm]

I'm also in the "no shuttle at all" camp. Launch vehicle & robotics technology will have matured enough to allow automated assembly of an entire station by the time the ISS is due for replacement. I think we would also get by without the shuttle in the first place. The S-IVB upper stage with the SLA adapter could house a 14-ton lunar module and the Apollo CSM could haul it around easily. The same model could work for on-orbit assembly. 14 tons is about half of the shuttle's payload capacity, but seems enough for most ISS modules. Anything larger could always be launched independently.

[Spartan125]

Make it SLS-style but make EVERY stage reusable and have different versions for different types of payload. The upper-stage ones will have heat protection of some sort. No more spaceplane either and will allow for better abort systems.

[Wahgineer]

By replacing the Shuttle with the Shuttle II, the only parts you dispose of every launch are relatively cheap ETs (4 shrunken down ones). The Shuttle II doesn't require a crawler, since it can be rolled out to the pad and then raised up to a vertical position there. It would have two reusable LFBEs (Liquid Fuel Booster Engines) that would detach after the first set of tanks to return to Earth. The entire tail swings down to release the payload inside, and the cockpit can separate to become its own spacecraft that can return to Earth.

[koshelenkovv]

I like the idea presented in this story. I'm pretty sure the Project NAILSPIKE part is total bunk, but the shuttle tweaks mentioned sounded pretty convincing. As I'm not a rocket scientist myself, I can't vouch for the accuracy of the science, but if it's anywhere close to correct it sounds great (if you don't mind a little hazardous exhaust )

“Take the space shuttle,†he said wistfully. “With just two tweaks, we could have put a hundred tons into its payload bay!â€Â

...

“All right. First, the solid rocket boosters. ... We could make them about twenty percent more efficient if we just replaced the aluminum with powdered beryllium. It’s a lighter atom and the redox reaction is more energeticâ€â€Ã¢â‚¬Â

...

“If you replace the oxidizer in the space shuttle main engines with liquid fluorine, you could also get an extra twenty percent out of them. And I know what you’re going to say next: wouldn’t that give rise to an exhaust plume of extremely hot hydrofluoric acid? You’re absolutely right: it would! But hydrofluoric acid reacts with beryllium oxide to give you beryllium fluorideâ€â€which is almost inert in comparisonâ€â€and hydrochloric acid, which is neither here nor there.â€Â

Main problem with these types of fuels isn't the fact that they are toxic. They are much more expensive, and fluorine is extremely corrosive.

[Kinglet]

Lifting body.

[RadHazard]

Main problem with these types of fuels isn't the fact that they are toxic. They are much more expensive, and fluorine is extremely corrosive.

Hmm... you're right. I looked it up and the costs were rather surprising. Beryllium was $930 per kg and Flourine was $1900 per kg. At those prices, it'd probably be cheaper to stuff dollar bills into the fuel tanks.

I did already know about the dangers of handling fluorine, but I didn't expect it to be so damn expensive.

Maybe Chlorine Trifluoride would be cheaper?

[Kulebron]

I'm also in the "no shuttle at all" camp. Launch vehicle & robotics technology will have matured enough to allow automated assembly of an entire station by the time the ISS is due for replacement.

Well, it was mature at a sufficient level in 1980-s, just parts were not small enough. Lunokhod was controlled with radio relay ships in Pacific and Atlantic. And Mir station modules were launched unmanned on a "space truck" Proton rocket, and docked automatically to the station.

Let me mention two things mentioned in this thread:

1. No tiles, just one piece heat shield. This makes sense if it is viscous enough to sustain partial damage and dissipate small impacts. Otherwise, if it's metallic and hard, any damage will cause cracks. Just for example, Tu-144 was made with several pieces of metal coating outside, to reduce the number of joints, and cracks on the plates, if started, ran through all the body. This caused a crash of one commercial flight of this machine. (Apart from 2 test flight crashes.) So, tiles make a lot of sense.

An alternative way is to hide the heatshield somewhere. In a certain transforming configuration the ship can just hide the wings behind. (I think Boeing proposed such design.)

2.

Well, let's try for a design that has wings to assist in the ascent. something like Space Ship Two or an Anteres rocket. Rides up to 50 km on a plane, then takes off with rocket propulsion and achieves orbit. do the wings help at any point during the ascent?

It's not so much wings as the ISP of the atmospheric engine that matters: ISP of jet engine is 4000, or ten times better than of a rocket. The problem is that if you launch from a plane, it can go not faster than Mach 2 (and it's extremely risky), but orbiting requires Mach 31. You save fuel on the initial 2 machs, at the cost of a huge system.

I think what could make sense are simple disposable wings. First stage flies on a SPEAR kind of engine high in the atmosphere, then drops the wings and procedes. Could make sense.

[Kulebron]

By the way, everyone is suggesting the designs, but did we consider what purpose should it serve?

Will it still be a space station like ISS, purely scientific, or maybe governments decide this SCIENCE is too expensive? Will it be a tourism attraction and a space hotel, or mixed with science?

Next, How much will reusability cost, especially, won't the engines require frequent dis- and reassembly to replace faulty parts? this may cost near as much as the production.

[DerekL1963]

especially, won't the engines require frequent dis- and reassembly to replace faulty parts? this may cost near as much as the production.

No and not true in the least bit.

[ravener]

disclaimer: i am no rocket scientist and most, if not all of this is just ideas.i am unsure of the feasability of some of this.

1. get rid of the heavy tiles and rely on breaking higher up in the atmosphere like skylon plans to, here wings would actually be useful. if you are light enough and have large enough surface area the heating would be managable. a fireproof (over 300 degrees c) piece of paper could survive reentry in the same way.

2. no humans, the pressurized part of the shuttle+lifesupport is too heavy to justify taking into space again and again.

3. no closed cargo compartment, the cargo is put on the back of the shuttle and a light fairing is around it (think a half fairing stuck on where the cockpit and cargo compartment was on the shuttle).

4. only two engines, with the weight savings from the earlier points you could use only two engines.

5. single part SRB's. the increesed reliability of a single piece pressure vessel is vital, not only to save face, but to keep "reusable" in the space shuttle. we should do everything that can increase the time between accidents.

6. slightly more fuel on the shuttle compared to the orange tank. for the high atmosphere braking to work the shuttle needs to be low density and have a large area, if we had more fuel on the shuttle the empty tanks would be structurally strong enough to make both possible.

7. an engine cluster on the orange tank. with more fuel on the shuttle the external tank would be smaller, with an engine cluster to assist during launch we could have a kind of "grasshopper" external tank that brakes before reentry and could possibly survive reentry (with some watercooling of critical surfaces. with some of the load taken off the shuttle it can be slightly smaller and rely more on its orbital engines than LHO engines.

Edited January 7, 2014 by ravener
grammar

[Nibb31]

disclaimer: i am no rocket scientist and most, if not all of this is just ideas.i am unsure of the feasability of some of this.

1. get rid of the heavy tiles and rely on breaking higher up in the atmosphere like skylon plans to, here wings would actually be useful. if you are light enough and have large enough surface area the heating would be managable. a fireproof (over 300 degrees c) piece of paper could survive reentry in the same way.

Braking (not breaking) before reentry requires propellant, which would be heavier than the tiles.

2. no humans, the pressurized part of the shuttle+lifesupport is too heavy to justify taking into space again and again.

3. no closed cargo compartment, the cargo is put on the back of the shuttle and a light fairing is around it (think a half fairing stuck on where the cockpit and cargo compartment was on the shuttle).

4. only two engines, with the weight savings from the earlier points you could use only two engines.

Then what's the point of returning home? What you describe is basically the expendable Shuttle-C concept.

Shuttle-C was a concept that actually made a lot of sense in parallel with the manned Shuttle. It would have had a cargo capacity of 70 to 80 tons, a rather low development cost, and easy integration in the VAB using existing Shuttle fixtures and procedures. The SLS is basically an inline version of this.

5. single part SRB's. the increesed reliability of a single piece pressure vessel is vital, not only to save face, but to keep "reusable" in the space shuttle. we should do everything that can increase the time between accidents.

The reason SRBs were in several segments was to be able to transport them by rail from the ATK manufacturing plant in Utah to KSC in Florida. Their size was defined by the railway tunnels on the way. To make them in one piece would require building a whole new SRB factory nearby KSC.

6. slightly more fuel on the shuttle compared to the orange tank. for the high atmosphere braking to work the shuttle needs to be low density and have a large area, if we had more fuel on the shuttle the empty tanks would be structurally strong enough to make both possible.

More propellant for the OMS engines means a heavier orbiter and less payload.

7. an engine cluster on the orange tank. with more fuel on the shuttle the external tank would be smaller, with an engine cluster to assist during launch we could have a kind of "grasshopper" external tank that brakes before reentry and could possibly survive reentry (with some watercooling of critical surfaces. with some of the load taken off the shuttle it can be slightly smaller and rely more on its orbital engines than LHO engines.

If you put the engines on the ET, you would be in a configuration similar to Energia-Buran. Reusing the core would be a big engineering challenge. Propulsive landing requires deep throttling which the SSMEs can't do, so you would have two options: stick huge wings on the core and it would be too heavy, or splash down in seawater, which would destroy the engines. The whole point of the STS was to reuse the SSMEs, so putting them on the core pretty much negates the whole point of having a heavy reusable orbiter in the first place.

Edited January 7, 2014 by Nibb31

[ravener]

when i said braking i was refering to re enering, the weight saving from removing the pressurized cockpit and tiles would let the shuttle reenter under lower, managable temperatures and could still be reused.

also, the shuttle would be a lot more expendable, but reusing the engines, electronics and other shuttle systems. the point is to make it cheap to use and cheap to keep in service.

Edited January 7, 2014 by ravener

[ravener]

If you put the engines on the ET, you would be in a configuration similar to Energia-Buran. Reusing the core would be a big engineering challenge. Propulsive landing requires deep throttling which the SSMEs can't do, so you would have two options: stick huge wings on the core and it would be too heavy, or splash down in seawater, which would destroy the engines. The whole point of the STS was to reuse the SSMEs, so putting them on the core pretty much negates the whole point of having a heavy reusable orbiter in the first place.

this is just to ease the reentry, those engines does not have to be that large and can burn the fuel left in the tank by the orbiter (a standard launch would leave some fuel in the tank as a safety mesure). you could spashdown with some parachutes. this is not too important though, the external tank could stay unpowered and burn on reentry.

[Nibb31]

this is just to ease the reentry, those engines does not have to be that large and can burn the fuel left in the tank by the orbiter (a standard launch would leave some fuel in the tank as a safety mesure). you could spashdown with some parachutes. this is not too important though, the external tank could stay unpowered and burn on reentry.

Who cares about reentry of the ET ?

when i said braking i was refering to re enering, the weight saving from removing the pressurized cockpit and tiles would let the shuttle reenter under lower, managable temperatures and could still be reused.

also, the shuttle would be a lot more expendable, but reusing the engines, electronics and other shuttle systems. the point is to make it cheap to use and cheap to keep in service.

It wouldn't be cheap at all. There is no economical reason to bring an unmanned spacecraft back. It just reduces your payload. Why launch an unmanned 80t orbiter with a 20t payload on board when you could simply launch a 100t payload on the same rocket (or launch your 20t payload on a cheap expendable rocket)?

And as I said, rocket braking instead of aerobraking requires massive amounts of propellant that you would need to carry up with you, which massively reduces your payload. Think about it: Braking from orbital speed to 0 requires the same amount of delta-v as for going from 0 to orbit, i.e. you need the same amount of propellant as you had on the launch pad. The Orbiter's OMS engines only had 300m/s of delta-v with ~4.5 tons of MMH fuel and ~8 tons of oxidizer. If your "manageable speed" is to hit the atmosphere at Mach 6 for example, you would need to 6000m/s of delta-v, meaning that you would need more than 20 times more OMS propellant: 90 tons of fuel and 140 tons of oxydizer.

As a comparison, the entire TPS (including tiles, thermal blankets, and RCC panels) only weighed 8.5 tons.

Edited January 7, 2014 by Nibb31

[ravener]

to be honest, i would rather not have a shuttle, the "improvements" would turn it closer and closer to a reusable third stage. just push the payload up there and come back for another run.

[DerekL1963]

The reason SRBs were in several segments was to be able to transport them by rail from the ATK manufacturing plant in Utah to KSC in Florida. Their size was defined by the railway tunnels on the way. To make them in one piece would require building a whole new SRB factory nearby KSC.

It would require more than just building a new SRB factory - it would require solving all of the unsolved technical issues that were a good part of what lead them to choose segmented boosters over monolithic boosters in the first place. Since, AFAIK, nobody has done any serious research and development on large monolithic boosters in forty years, you'd be all but starting from scratch.

[Kulebron]

We've discussed Shuttle a lot with Firov in the other thread and came to conclusion (probably K^2 made this point) that Shuttle did what in Russian space programme a whole fleet of ships does. So instead of a swiss knife it would better to start with specialized ships and then solve the issues that a reusable SSTO was designed to solve: the fast repeatability of flights.

This was not doable with Shuttle, because there were few of them, and preparation took quite long time, and was expensive. Soyuz rockets are better, one is launched every 1-2 weeks, but this may be too much of a waiting as well. In this case, an approach by SpaceX (if those rockets won't need reassembly for maintenance) could work.

[DerekL1963]

We've discussed Shuttle a lot with Firov in the other thread and came to conclusion (probably K^2 made this point) that Shuttle did what in Russian space programme a whole fleet of ships does. So instead of a swiss knife it would better to start with specialized ships and then solve the issues that a reusable SSTO was designed to solve: the fast repeatability of flights.

But if all you fly is specialized ships, you'll never solve the issues - you can only improve what you fly.

This was not doable with Shuttle, because there were few of them, and preparation took quite long time, and was expensive. Soyuz rockets are better, one is launched every 1-2 weeks, but this may be too much of a waiting as well. In this case, an approach by SpaceX (if those rockets won't need reassembly for maintenance) could work.

If your metric is "small, low capability boosters/capsules" (depending on which Soyuz you mean), then yes, they were better. But that's like claiming a Ford Focus is "better" than a bulldozer or a cab-over Pete. Before you can reasonably define better, you have to answer the question "better at what?" and make for d--- sure that you're comparing apples to apples.

[Kulebron]

Soyuz and Proton boosters scale up to Shuttle's tasks. Everything except taking a big satellite to Earth. But you can build a specialized ship for this too, and rendezvous it with the satellite, and with manned ship as well.

Can you name a practical task a fleet can't do?

[KASASpace]

Soyuz and Proton boosters scale up to Shuttle's tasks. Everything except taking a big satellite to Earth. But you can build a specialized ship for this too, and rendezvous it with the satellite, and with manned ship as well.

Can you name a practical task a fleet can't do?

Do you even no about Energia? about 100 tons to orbit, weight of shuttle is over 100 tons, cargo to orbit for shuttle was 30 tons.......

[KASASpace]

The problem is that if you launch from a plane, it can go not faster than Mach 2 (and it's extremely risky), but orbiting requires Mach 31. You save fuel on the initial 2 machs, at the cost of a huge system.

Are we forgetting that scramjets have gotten planes to Mach 12? Which is 11,000 mph, or only then you need 6,000 mph to gain with rockets, not counting drag.

[Kulebron]

Do you even no about Energia? about 100 tons to orbit, weight of shuttle is over 100 tons, cargo to orbit for shuttle was 30 tons.......

I do know. What's your point?

[Armchair Rocket Scientist]

Are we forgetting that scramjets have gotten planes to Mach 12? Which is 11,000 mph, or only then you need 6,000 mph to gain with rockets, not counting drag.

Scramjets have gotten a vehicle pretty much built around the scramjets to just under mach 10, but that was with a B-52 to carry the thing and a rocket to get it up to hypersonic speeds so the scramjets would function. IIRC scramjets have a horrible TWR, so building a scramjet-powered vehicle that can cope with the weight and drag of rocket engines and fuel for the final ascent to orbit would be very difficult. If you want it to be reusable you need a heatshield which can withstand reentry from orbit, not just whatever speed the jets get it up to. If you want an SSTO you also have to carry some combination of ramjets, turbojets, or even more rocket fuel for takeoff and acceleration to mach 5 or so. So far, scramjets are hard enough to make work at all, let alone as a viable launch vehicle.

Currently, technologies like pre-cooled jet engines (e.g. SABREs) and pulsedet engines getting a plane from zero to mach 5 with one set of airbreathing engines seems much more feasible than getting it to mach 10 on three.