I was thinking about all the complexity of the Space Shuttle the other day, and how much extra mass it must carry just for the minutes of re-entry.
I was wondering if with the modern ceramic coatings & so-on it would have been possible to use the mass of the thousands of heat tiles and other insulated areas to coat the Shuttle with a good heat-resistant ceramic covering (not very heavy) and with the spare mass use that for fuel to run the OMS rockets to slow the Shuttle as much as possible before it enters the heating phase of re-entry?
I’m not confident it would be a workable thing ….. just thinking out loud.

Spiny Norman said:

I was thinking about all the complexity of the Space Shuttle the other day, and how much extra mass it must carry just for the minutes of re-entry.
I was wondering if with the modern ceramic coatings & so-on it would have been possible to use the mass of the thousands of heat tiles and other insulated areas to coat the Shuttle with a good heat-resistant ceramic covering (not very heavy) and with the spare mass use that for fuel to run the OMS rockets to slow the Shuttle as much as possible before it enters the heating phase of re-entry?
I’m not confident it would be a workable thing ….. just thinking out loud.

a space shuttle as we know it should be sat atop of the rocket , not on the side. it was a terrible mistake to do what they did. a spaceshuttle on the very top doesn’t have to worry about things falling off the tank/ boosters. it also makes for a shape that has less drag.

slowing the shuttle down would be another option, relying on the magic of heat resistant tiles that seem to be fragile leaves the door wide open for disaster.

wookiemeister said:

Spiny Norman said:

I was thinking about all the complexity of the Space Shuttle the other day, and how much extra mass it must carry just for the minutes of re-entry.
I was wondering if with the modern ceramic coatings & so-on it would have been possible to use the mass of the thousands of heat tiles and other insulated areas to coat the Shuttle with a good heat-resistant ceramic covering (not very heavy) and with the spare mass use that for fuel to run the OMS rockets to slow the Shuttle as much as possible before it enters the heating phase of re-entry?
I’m not confident it would be a workable thing ….. just thinking out loud.

a space shuttle as we know it should be sat atop of the rocket , not on the side. it was a terrible mistake to do what they did. a spaceshuttle on the very top doesn’t have to worry about things falling off the tank/ boosters. it also makes for a shape that has less drag.

slowing the shuttle down would be another option, relying on the magic of heat resistant tiles that seem to be fragile leaves the door wide open for disaster.

You are obviously not aware that a good part of the lift thrust is provided by the shuttle engines.

This is why the shuttle is mounted as it is.

The shuttle is the rocket in this case.

jjjust moi said:

wookiemeister said:

Spiny Norman said:

I was thinking about all the complexity of the Space Shuttle the other day, and how much extra mass it must carry just for the minutes of re-entry.
I was wondering if with the modern ceramic coatings & so-on it would have been possible to use the mass of the thousands of heat tiles and other insulated areas to coat the Shuttle with a good heat-resistant ceramic covering (not very heavy) and with the spare mass use that for fuel to run the OMS rockets to slow the Shuttle as much as possible before it enters the heating phase of re-entry?
I’m not confident it would be a workable thing ….. just thinking out loud.

a space shuttle as we know it should be sat atop of the rocket , not on the side. it was a terrible mistake to do what they did. a spaceshuttle on the very top doesn’t have to worry about things falling off the tank/ boosters. it also makes for a shape that has less drag.

slowing the shuttle down would be another option, relying on the magic of heat resistant tiles that seem to be fragile leaves the door wide open for disaster.

You are obviously not aware that a good part of the lift thrust is provided by the shuttle engines.

This is why the shuttle is mounted as it is.

and that by mounting the space shuttle where it is has led to catastrophic failure

don’t build failure into the design

normal rockets have more than enough power to lift a smaller space shuttle

they should have continued the simple kerosene oxygen Saturn V for launching a space shuttle – this idea had been on the drawing board for ages. instead the yanks decided to waste more money on time building a new machine when they already had a proven launch system in the Saturn V.

how would these coatings handle the vibration of the shuttle on lift-off and expansion of the skin on re-entry? can you get pliable ceramic coatings?

I don’t understand the question. The tiles that they use are extremely lightweight. There hasn’t been any radical change in refractory technology or the laws of physics in the last few years. Highly insulating materials are highly porous, as these tiles are. There isn’t any room to reduce the weight any further.

They had even done away with painting the booster rocket casings to save on mass, it saved quite a bit.

ChrispenEvan said:

how would these coatings handle the vibration of the shuttle on lift-off and expansion of the skin on re-entry? can you get pliable ceramic coatings?

Easily – They survive for years on the exhaust of racing cars. The pipes glow bright red under full power.

morrie said:

I don’t understand the question. The tiles that they use are extremely lightweight. There hasn’t been any radical change in refractory technology or the laws of physics in the last few years. Highly insulating materials are highly porous, as these tiles are. There isn’t any room to reduce the weight any further.

They’d still mass hundreds of kilograms. That’s a fair bit of fuel.
The ceramics tend to reflect the heat rather than insulate.

Spiny Norman said:

morrie said:

I don’t understand the question. The tiles that they use are extremely lightweight. There hasn’t been any radical change in refractory technology or the laws of physics in the last few years. Highly insulating materials are highly porous, as these tiles are. There isn’t any room to reduce the weight any further.

They’d still mass hundreds of kilograms. That’s a fair bit of fuel.
The ceramics tend to reflect the heat rather than insulate.

You can read all about it in Wiki. They have used flexible insulation. It has been around for 50 years. The tiles have a density of 144kg/m3 and are 90 percent air. That’s hard to improve on. You can’t reflect without insulating.

http://en.wikipedia.org/wiki/Space_Shuttle_thermal_protection_system

There is a fundamental relationship between material strength and porosity. Strength falls away dramatically at high porosities.

You’re using the atmosphere to aero brake from 18,000 m/hr for a very little delta-v de-orbit burn.

You’d need to due a massive burn to shed off that sort of V.. Even at 2,000 m/hr the frictional forces on the craft would be massive. And that’s after wedding 8/9ths of its velocity

Dropbear said:

You’re using the atmosphere to aero brake from 18,000 m/hr for a very little delta-v de-orbit burn.

You’d need to due a massive burn to shed off that sort of V.. Even at 2,000 m/hr the frictional forces on the craft would be massive. And that’s after wedding 8/9ths of its velocity

Do

Shedding

Fn iOS

It was designed 30 years ago, watchagonnado. Given that it’s been discontinued I don’t think that they will work on making these improvements…

One would hope that any new designed return craft would take advantage of modern advances in material science. At the moment, any return craft in use are much smaller, including the SpaceX Dragon, which uses a composites-based ablative cone. It might be that the era of 100 ton reentry vehicles has passed.

As Bear says, unless you’ve got a shed load of power on board there is always going to be a fiery homecoming.
You need to expend the same amount of energy to get down as it took to get up there I think.
.

I’m afraid that I feel life is too short to use part of a Sunday morning correcting wookie.

dv said:

I’m afraid that I feel life is too short to use part of a Sunday morning correcting wookie.

I usually don’t.

Must have been feeling charitable……or sumfink.

dv said:

It was designed 30 years ago, watchagonnado. Given that it’s been discontinued I don’t think that they will work on making these improvements…

One would hope that any new designed return craft would take advantage of modern advances in material science. At the moment, any return craft in use are much smaller, including the SpaceX Dragon, which uses a composites-based ablative cone. It might be that the era of 100 ton reentry vehicles has passed.

The point is, there is little room to move in terms of material science. As you have pointed out, design has changed. When you consider these things, whether it be in earthly situations or in space applications there are 4 interacting factors. Materials, design, maintenance practice and operating practice. While these things interact, design is usually the single biggest factor.

It would be a lot harder to land on a planet the size of Earth that didn’t have an atmosphere.
No atmosphere to dissipate your energy with fiery friction, no atmosphere to finish it off with a parachute.
It’d be retro rockets all the way and a shed load of fuel.

Yeah but why would you want to?

Moreover, it would be a bit odd for an Earth sized planet to have no atmosphere.

dv said:

Yeah but why would you want to?

sshhhhh

>>Yeah but why would you want to?

Because of the compelling urge of man to explore and to discover, the thrust of curiosity that leads men to try to go where no one has gone before.
To seek out new marketing opportunities for our nitrogen/oxygen gas mix with a factory bonus cash back no more to pay walk away offer.

Peak Warming Man said:

>>Yeah but why would you want to?

Because of the compelling urge of man to explore and to discover, the thrust of curiosity that leads men to try to go where no one has gone before.
To seek out new marketing opportunities for our nitrogen/oxygen gas mix with a factory bonus cash back no more to pay walk away offer.

You forgot extended warranty?

My gut feeling is that the mass saved through changing the heat shielding wouldn’t give enough extra fuel to make a significant difference to re-entry speed. But I have no idea where to start on doing the calculations to prove it.

It’d be retro rockets all the way and a shed load of fuel.

maybe even two sheds worth of fuel.

> with a good heat-resistant ceramic covering (not very heavy)

That’s exactly what the shuttle tiles are anyway. Minimum-weight heat-resistant ceramic.

> with the spare mass use that for fuel to run the OMS rockets to slow the Shuttle as much as possible before it enters the heating phase of re-entry?

That’s already being done, too. The Shuttle is slowed much more than all other types of re-entry vehicle. It reenters at, if I remember correctly, only about half the reentry speed of the Apollo capsule.

mollwollfumble said:

> with the spare mass use that for fuel to run the OMS rockets to slow the Shuttle as much as possible before it enters the heating phase of re-entry?

That’s already being done, too. The Shuttle is slowed much more than all other types of re-entry vehicle. It reenters at, if I remember correctly, only about half the reentry speed of the Apollo capsule.

The low speed of shuttle re-entry is more to do with it is only in LEO, it is not falling back from the moon like Apollo.