Completely crazy idea? Or just might work? (It doesn't)

[Spaceception]

So, I have a potentially crazy idea;

So say you have a Spaceplane, like Dream Chaser or Skylon, but the heat shield tiles are exposed, meaning during liftoff, they could be damaged, so what if we had this on our Spacecraft?

1 One single heat shield, no tiles

And

2 And a very thin, lightweight (Aluminum/Carbon fiber) hull plate over the heat shield to protect the shield from damage. (That would burn up during reentry, exposing the heat shield)

I have a question about this;

If the Space Shuttles had this, could Colombia have been saved?

Edited March 4, 2016 by Spaceception

[sevenperforce]

Heavy. 

Really, really heavy. 

They stopped painting the external tank because the weight of the white paint was too great. 

(IIRC, paint probably would have kept the foam from breaking off and striking Columbia in the first place.)

The fact is, we never should have put our crew vehicle anywhere other than on the very top of our rockets. The side-slung configuration was chosen so that the Shuttle's engines could thrust from launch to orbit.

[Spaceception]

6 minutes ago, sevenperforce said:

Heavy. 

Really, really heavy. 

They stopped painting the external tank because the weight of the white paint was too great. 

(IIRC, paint probably would have kept the foam from breaking off and striking Columbia in the first place.)

The fact is, we never should have put our crew vehicle anywhere other than on the very top of our rockets. The side-slung configuration was chosen so that the Shuttle's engines could thrust from launch to orbit.

I should have put this in, but it's more like a thin sheet to prevent heat shield chunks coming off.

[p1t1o]

34 minutes ago, Spaceception said:

...hull plate over the heat shield...

If the Space Shuttles had this, could Colombia have been saved?

Well, obviously, if it had been sturdy enough, yes, a strong enough armour plate over the impact-damaged portion of heatshield would have protected it from impact. But how thick? Made of what? Why not encase astronauts inside lifepods made of 8-inch steel, each with multi-redundant parachutes and heatshields of their own too?

As seven said, too massy.

Ooh, also just thought: By plating your shuttle (or any other craft) in expendable armour, you are also adding far more opportunities for something (potentially heavier and stronger) else to break off and impact parts of the vehicle. Try working out the risk assessment for that!

 

**edit**

34 minutes ago, Spaceception said:

...plate over the heat shield to protect the shield from damage...

9 minutes ago, Spaceception said:

I should have put this in, but it's more like a thin sheet to prevent heat shield chunks coming off.

I'm confused, do you mean a layer over the [shuttle] heatshield, or a layer over the foam external tank insulation? Either way, same answer, too massy. Thats the answer to almost any "why dont they have X" question.

Im sure if mass wasn't an issue the shuttle probably would have had a cappuccino machine.

**edit #2**

I suddenly feel like cappucino machine wasn't unrealistic enough, pretend I said Jacuzzi.

Edited March 4, 2016 by p1t1o

[alpha tech]

The space shuttle is made of aluminum I don't see why it is not made of steel or titanium like on STS-27 I think is the mission the only reason it survived is because where the tile was under it was a piece of steel that was melted completely and it started on the aluminum I don't see why it doesn't have a stronger metal that aluminum. This was on secrets space escapes so you should check it out if you have time. And at one time the space shuttle had ejection seats before they added more crew

 

Edited March 4, 2016 by alpha tech

[Nibb31]

There is no reason for Skylon or Dream Chaser to be hit by debris during take off, since they aren't travelling on the side of a huge cryo tank that sheds foam and blocks of ice.

It would also introduce a whole lot of failure modes. Does your protective layer burn off like the layer of Kapton on Apollo and then how much does it cost in maintenance? or is it jettisonned, and if so, how? and what happens if the jettison fails?

Edited March 4, 2016 by Nibb31

[p1t1o]

2 minutes ago, alpha tech said:

I don't see why it doesn't have a stronger metal that aluminum

Mass mass, massmassmass, massy massy massy mass-mass.

Mass?

[alpha tech]

it still doesn't matter about mass it could b made of light weight steel or titanium or on big carbon - carbon tiles

[Nibb31]

Titanium was considered too expensive. Remember they wanted to build a whole fleet of Shuttles. And aluminium was considered fine as long as the TPS remained intact. Titanium is about 60% heavier than Aluminium, which would have made a huge difference in payload fraction.

[p1t1o]

8 minutes ago, alpha tech said:

it still doesn't matter about mass it could b made of light weight steel or titanium or on big carbon - carbon tiles

No such thing as "lightweight steel".

Titanium has its own properties which aren't always desirable (its more brittle for example) however, the biggest deal is cost, titanium is SUPER expensive compared to steel or aluminium.

Carbon-carbon tiles are EVEN MORE expensive than titanium and are worth sh** structurally - dont know why you brought them up.

Ejection seat are useless except for about the first minute or so of flight, after that an ejection would rip you to pieces, during reentry? forget it. (also, maaaaaaaaaass)

Also I dont know what "secrets space escapes" is but just by its name it sounds super dubious.

<google>

Oh look, discovery channel! Yeah, take what they say with a pinch [or nine] of salt.

Sorry, not discovery channel - "Discovery Science", still, doesn't exactly sound that solid.

Edited March 4, 2016 by p1t1o

[Spaceception]

11 minutes ago, Nibb31 said:

There is no reason for Skylon or Dream Chaser to be hit by debris during take off, since they aren't travelling on the side of a huge cryo tank that sheds foam and blocks of ice.

I doubt a "thin layer" of anything would have protected the Columbia's RCC panels. A protection would either be heavy and protective or thin and useless. You can't have it both ways.

It would also introduce a whole lot of failure modes. Does your protective layer burn off like the layer of Kapton on Apollo and then how much does it cost in maintenance? or is it jettisonned, and if so, how? and what happens if the jettison fails?

It would burn off during reentry, and be a Aluminum/Carbon fiber composite.

[Nibb31]

This is the sort of hole that brought down Columbia:

That was produced by an 800 gram chunk of foam that was shot at Mach 0.8 at the wing edge during the CAIB investigation.

I doubt a "thin layer" of anything would have protected the Columbia's RCC panels. A protection would either be heavy and protective or thin and useless. You can't have it both ways.

If there was an easy fix, don't you think the smart folks at NASA would have implemented it for the RTF ?

But again, we've learned our lessons, and nobody is going to be proposing a side-mounted manned vehicle for a long time, so the whole point is moot.

Edited March 4, 2016 by Nibb31

[alpha tech]

1 minute ago, Nibb31 said:

Titanium was considered too expensive. Remember they wanted to build a whole fleet of Shuttles. And aluminium was considered fine as long as the TPS remained intact. Titanium is about 60% heavier than Aluminium, which would have made a huge difference in payload fraction.

the soviets made buran ad it could carry more than the shuttle. So what about steel and why did nasa not have procedures in place for a situation like this they removed ejector seats and that is the main reason I didn't like the shuttle one tile comes off your SOL. Unless you have a Soyuz with a docking adapter

[Spaceception]

Just now, Nibb31 said:

[Snip]

Sigh Alright, it was just an idea

[p1t1o]

To help illustrate the mass problem:

A layer of *paint* on a 747 weighs 550 pounds.

I know w shuttle is smaller than a 747, and 550 pounds isn't *that* much.

But those 550 pounds come directly off your payload fraction, and we are talking about a layer of *paint* here.

[alpha tech]

Just now, Spaceception said:

Sigh Alright, it was just an idea

but a damn good one i wondered this for years

[alpha tech]

27 minutes ago, p1t1o said:

No such thing as "lightweight steel".

Titanium has its own properties which aren't always desirable (its more brittle for example) however, the biggest deal is cost, titanium is SUPER expensive compared to steel or aluminium.

Carbon-carbon tiles are EVEN MORE expensive than titanium and are worth sh** structurally - dont know why you brought them up.

Ejection seat are useless except for about the first minute or so of flight, after that an ejection would rip you to pieces, during reentry? forget it. (also, maaaaaaaaaass)

Also I dont know what "secrets space escapes" is but just by its name it sounds super dubious.

<google>

Oh look, discovery channel! Yeah, take what they say with a pinch [or nine] of salt.

Sorry, not discovery channel - "Discovery Science", still, doesn't exactly sound that solid.

I brought the carbon - carbon tiles up because they can stand the 3000 degree heat and they make specialized suits for ejection at mach 2.7 that is what astronauts pressurize their suits on reentry cause the pressure inside is what matters the outside pressure is canceled out. And secret space escapes comes on every Tuesday night on science channel. EST. Oh yeah galvanized steel is light weight.

 

here is a link for secret space escapes

 

http://www.sciencechannel.com/tv-shows/secret-space-escapes/

Edited March 4, 2016 by alpha tech

[Nibb31]

22 minutes ago, alpha tech said:

the soviets made buran ad it could carry more than the shuttle. So what about steel and why did nasa not have procedures in place for a situation like this they removed ejector seats and that is the main reason I didn't like the shuttle one tile comes off your SOL. Unless you have a Soyuz with a docking adapter

You're just all mixed up.

Buran is not comparable. First of all, the Buran orbiter didn't even have engines and used an entirely different architecture with entirely different requirements. It also only flew a single unmanned test flight, so it's hard to extrapolate on what its actual capabilities would have been.

Columbia had two ejection seats for the first test flights, but like Gemini, they wouldn't have been of much help during most of the flight. There was never any provision for ejection of a six or seven person crew (especially as two or three were seated in the lower deck).

A Soyuz docking adapter (whatever that is) wouldn't have helped Columbia. Why would the Shuttle carry a female probe-and-drogue system? The other Shuttles had the Russian APAS docking system, inherited from the Shuttle-Mir program, but Soyuz doesn't use APAS. Soyuz was also unable to reach Columbia's inclination and unable to carry everyone back anyway. I suggest you read the thread about the Columbia rescue theories.

Edited March 4, 2016 by Nibb31

[alpha tech]

3 minutes ago, Nibb31 said:

You're just all mixed up.

Buran is not comparable. First of all, the Buran orbiter didn't even have engines and used an entirely different architecture with entirely different requirements. I also only flew once, so it's hard to extrapolate on what its actual capabilities would have been.

Columbia had two ejection seats for the first test flights, but like Gemini, they wouldn't have been of much help during most of the flight. There was never any provision for ejection of a six or seven person crew (especially as two or three were seated in the lower deck).

A Soyuz docking adapter (whatever that is) wouldn't have helped Columbia. Why would the Shuttle carry a female probe-and-drogue system? The other Shuttles had the Russian APAS docking system, inherited from the Shuttle-Mir program, but Soyuz doesn't use APAS. Soyuz was also unable to reach Columbia's inclination and unable to carry everyone back anyway. I suggest you read the thread about the Columbia rescue theories.

well the Soyuz still could have rendezvous with the shuttle and the crew could Eva over. Also buran used Liquid fuel for solid rocket boosters and that could have saved challenger cause u can cutoff fuel.

Edited March 4, 2016 by alpha tech

[p1t1o]

1 minute ago, alpha tech said:

I brought the carbon - carbon tiles up because they can stand the 3000 degree heat and they make specialized suits for ejection at mach 2.7 that is what astronauts pressurize their suits on reentry cause the pressure inside is what matters the outside pressure is canceled out. And secret space escapes comes on every Tuesday night on science channel. EST.

Just trust me on the ejection seat, they would be useful only for a very small proportion of the envelope.

The space shuttle considers Mach 2.7 pretty much a crawl. Mach 3 is reached approx 2mins after launch, and on reentry, Mach 3 is reached about 6 mins before touchdown at an altitude of about 30k feet.

Another note, I'm not sure what experience you have with military aircraft, but ejection seat are considered *very dangerous*. There are many examples of seats going off by accident, sometimes in flight, sometimes on the ground. I heard one story of one that went off whilst being service and absolutely *demolished* the person working on it.

The fact that they have arming pins like grenades should be illustrative.

[alpha tech]

2 minutes ago, p1t1o said:

Just trust me on the ejection seat, they would be useful only for a very small proportion of the envelope.

The space shuttle considers Mach 2.7 pretty much a crawl. Mach 3 is reached approx 2mins after launch, and on reentry, Mach 3 is reached about 6 mins before touchdown at an altitude of about 30k feet.

Another note, I'm not sure what experience you have with military aircraft, but ejection seat are considered *very dangerous*. There are many examples of seats going off by accident, sometimes in flight, sometimes on the ground. I heard one story of one that went off whilst being service and absolutely *demolished* the person working on it.

The fact that they have arming pins like grenades should be illustrative.

there still a good ting to have tough after challenger they gave the crew parachutes

[Nibb31]

8 minutes ago, alpha tech said:

well the Soyuz still could have rendezvous with the shuttle and the crew could Eva over. Also buran used Liquid fuel for solid rocket boosters and that could have saved challenger cause u can cutoff fuel.

No it couldn't. Soyuz couldn't reach the inclination of Columbia. And Soyuz has no EVA capability.

If Challenger had used liquid boosters, it wouldn't have had O-rings so they couldn't have leaked and the accident wouldn't have happened. Also, even if they did have a way to a shut down the SRBs, the damage was done as soon as the burn-through in the ET had happened. Liquid rockets have their own failure modes, they aren't inherently better or safer, they are just different. 

I think you've been watching too much History Channel.

Edited March 4, 2016 by Nibb31

[alpha tech]

you know what would be cool have a docking nosecone and attach an Les to it and make it where it would cutoff at the cargo bay then bail or eject

[p1t1o]

2 minutes ago, alpha tech said:

there still a good ting to have tough after challenger they gave the crew parachutes

Come on man, google is friendly:

https://en.wikipedia.org/wiki/Space_Shuttle_abort_modes#Ejection_escape_systems

• Very difficult to eject seven crew members when three or four were on the middeck (roughly the center of the forward fuselage), surrounded by substantial vehicle structure.
• Limited ejection envelope. Ejection seats only work up to about 3,400 miles per hour (3,000 kn; 5,500 km/h) and 130,000 feet (39,624 m). That constituted a very limited portion of the shuttle's operating envelope, about the first 100 seconds of the 510 seconds powered ascent.
• No help during Columbia-type reentry accident. Ejecting during an atmospheric reentry accident would have been fatal due to the high temperatures and wind blast at high Mach speeds.
• Astronauts were skeptical of the ejector seats' usefulness. STS-1 pilot Robert Crippen stated:

n truth, if you had to use them while the solids were there, I don’t believe you’d—if you popped out and then went down through the fire trail that’s behind the solids, that you would have ever survived, or if you did, you wouldn't have a parachute, because it would have been burned up in the process. But by the time the solids had burned out, you were up to too high an altitude to use it. ... So I personally didn't feel that the ejection seats were really going to help us out if we really ran into a contingency.^[11]

 

And on parachutes after Challenger:

A particular significant enhancement was bailout capability. This is notejection as with a fighter plane, but an Inflight Crew Escape System[9](ICES). The vehicle was put in a stable glide on autopilot, the hatch was blown, and the crew slid out a pole to clear the orbiter's left wing. They would then parachute to earth or the sea. While this may at first appear only usable under rare conditions, there were many failure modes where reaching an emergency landing site was not possible yet the vehicle was still intact and under control.

[RizzoTheRat]

12 minutes ago, alpha tech said:

Oh yeah galvanized steel is light weight.

Material weight is a bit a red herring though, as the mechanical strength obviously varies with weight and temperature.  For example aluminium is less dense than steel, but an aluminium SCUBA air cylinder is actually heavier than a steel one because you need to use more metal to get the structural strength, but other properties of the material make it a good choice.

 

8 minutes ago, p1t1o said:

Another note, I'm not sure what experience you have with military aircraft, but ejection seat are considered *very dangerous*. There are many examples of seats going off by accident, sometimes in flight, sometimes on the ground. I heard one story of one that went off whilst being service and absolutely *demolished* the person working on it.

I went to a talk by a guy from Martin-Baker (British ejector seat manufacturer) some years ago, who reckoned ejector seats had claimed more lives (ie accidental deaths of ground crew) than they'd saved.