Shuttle Orbiter, test to failure?

[rocketwatcher2001]

I think it's a given that NASA, or someone else will eventually fly another space plane again in the future, similar to the Orbiter, and it will have similar re-entry heating protection. One of the things I would like to see in the future is a full test to failure during reentry with the test vehicle loaded with sensors that can very closely moniter the destrution of the vehicle. NASA learned a lot from intentionally crashing airplanes in controlled environments, and it's made airplanes a lot safer. We have computer models of high mach heating that are very good, we think, but nothing beats a real world test. I have to wonder how different the Space Shuttle would be if we knew in the 70's what we know today.<br /><br />Would we have sacrificed ISP for non-cryogenic fuels that don't have no need for foam on the tanks? Would we have assembled the stack differently with a big Saturn booster and no SSME's, and the Orbiter on top, and some type of stablizers to to keep the center of pressure behind the center of gravity? <br /><br />Don't get me wrong, I think the Space Shuttle is a masterpiece of space equipment, but I know there is a better way to do it next time. We learn, we advance. It took a lot of work to go from the Wright brothers Flyer to the 747. <div class="Discussion_UserSignature"> </div>

 

[dragon04]

<font color="yellow">Don't get me wrong, I think the Space Shuttle is a masterpiece of space equipment, but I know there is a better way to do it next time.</font><br /><br />I utterly agree. I think that what will re-open that door is if we can come up with a more advanced propulsion system that makes an Orbiter a <b>true</b> space plane.<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[jimfromnsf]

"One of the things I would like to see in the future is a full test to failure during reentry with the test vehicle loaded with sensors that can very closely moniter the destrution of the vehicle."<br /><br />Columbia did this. There is anymore to be gained.<br /><br />"Would we have sacrificed ISP for non-cryogenic fuels that don't have no need for foam on the tanks?"<br /><br />No, just need better TPS<br /><br />"some type of stablizers to to keep the center of pressure behind the center of gravity?"<br /><br />These aren't model rockets. Real launch vehicles don't follow this rule. They are all tail heavy

 

[kelvinzero]

(hope this isnt too off topic)<br />Any reasonable designs lying around for what the next generation shuttle would have been? I mean without major breakthroughs, just fixing the shuttle issues while still aiming for a fair degree of reusability.<br /><br />I had a quick google but only found this:<br />http://www.popularmechanics.com/science/air_space/1534782.html

 

[baktothemoon]

What do you thing the X-33 was supposed to be?

 

[baktothemoon]

>No, just need better TPS<br /><br />Let me ask this question: if we had to build a better shuttle today, how would we build the TPS system? The rules for this question are you can't say that we should eliminate the ET, it has to involve current tech, and you can just say we shouldn't make another shuttle at all.

 

[jimfromnsf]

Put the orbiter above the ET

 

[vogon13]

BTDT . . . <br /><br /><img src="/images/icons/frown.gif" /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[rocketwatcher2001]

<font color="yellow">One of the things I would like to see in the future is a full test to failure during reentry with the test vehicle loaded with sensors that can very closely moniter the destrution of the vehicle." <br /><br />Columbia did this. There is anymore to be gained. </font><br /><br />Sure there is.<br /><br /><br /><font color="yellow">some type of stablizers to to keep the center of pressure behind the center of gravity?" <br /><br />These aren't model rockets. Real launch vehicles don't follow this rule. They are all tail heavy </font><br /><br />So why was the Soviet Shuttle Buran mounted aft and sideways instead of on top? It was to keep the CP as aft as possible to lessen the workload of the guidance system, especially as it went through maxQ. From a parisitic drag perspective the side mounted Buran is a high drag design requiring a lot of extra fuel. Why else would they do that? <div class="Discussion_UserSignature"> </div>

 

[rocketwatcher2001]

<font color="yellow">Put the orbiter above the ET</font><br /><br />I can't imagine that engine gimbling could keep it stable. On the other hand, if the wings were removed, it would probably work, but it would reduce cross range, and increase landing speed. Some folks, John Young being one of them, thought that a wingless lifting body would be too fast to land safely, but I think today's advanced flight control computers can make it happen....you just need a long runway ,and a drag chute wouldn't hurt, either. <div class="Discussion_UserSignature"> </div>

 

[dragon04]

While it doesn't seem likely to ever happen, I was thinking more about a space plane capable of powered descent.<br /><br />I don't know how much of a future there is in lifting bodies if they can't do that. <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[vulture2]

If the orbiter were above the ET, would the engines have to be mounted on the ET, and be expendable? I'm not saying this is a problem, since the RS-68 is available, but it should be considered. I can't imagine the orbiter towing the ET behind it. <br /><br />Another approach is to use nonfoam insulation on the ET, like the reusable system that was sucessfully tested for the X-33 composite hydrogen tank. I believe it used a plastic honeycomb layer _inside_ the tank shell, with a layer of metallic foil to provide a seal. When hydrogen fills the tank, the air in the honeycomb freezes, leaving a vacuum that insulates the tank. <br /><br />People have been trying to apply insulation has been applied to the outside of rockets since vermiculite was glued onto the V-2 nosecone. It is still problematic.

 

[jimfromnsf]

This talk of CP behind CG is BS. You guys don't know "real" rocket science. Look at a Titan-IV with an 86' fairing or an Atlas V 501. The CP is way forward with the sail area of the fairings. Also the payload mass in the fairing is relatively light wrt rest of vehicle. Look at all the SRM's on a Delta II, it is very tail heavy. <br />Early designs of the shuttle had the orbiter on top of an S-IC. OSP was to be on TOP of ELV's<br /><br />CP/CG relationship in launch vehicle is not as important as for unguided model rockets

 

[jimfromnsf]

"Columbia did this. There isn't anymore to be gained.<br /><br />Sure there is. "<br /><br />And you are making this call based on what. The little information gained isn't worth the money for any type of this experiment.<br /><br />"So why was the Soviet Shuttle Buran mounted aft and sideways instead of on top?"<br /><br />It made less impacts on ground faciliities. It was easier to switch from a cargo pod to an orbiter on the side and it wasn't as high. And it was like the US version. CP location wasn't a consideration<br />

 

[strandedonearth]

<br />I'm not going to pretend that I know more than people that actually work for the space program, but I can easily see that largish wings too far forward of the CG would challenge even the most robust guidance systems.<br /><br />One solution for an aircraft-like orbiter on top of a booster would be retractable wings. Retracted for liftoff, the guidance system wouldn't get overloaded. Extended in orbit, the surface could be used for solar panels and/or radiators. Retracted again for re-entry, less surface area need to be protected from the heat. Fully extended for final approach, the landing speed and sink rate can be safe and sane.<br /><br />While I have no doubt it would be a considerable technical challenge, given that aircraft with variable geometry wings are already flying, I don't think the challenge would be insurmountable.

 

[rocketwatcher2001]

<font color="yellow">It was easier to switch from a cargo pod to an orbiter on the side and it wasn't as high.</font><br /><br />The Soviet Orbiter stack was always horizontal until just before launch, so how "high" it was never mattered.<br /><br /><br /><font color="yellow">CP location wasn't a consideration</font><br /><br />Actually, it was the main consideration.<br /><br /><i>Wind tunnel tests were conducted on a wide range of possible arrangements of rocket stages and orbiter positions. In the end, Buran was moved to the lateral position, as with the US space shuttle. </i><br />http://www.astronautix.com/craft/buran.htm <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

Astronautix is not a valid reference. Unfortunately, it is tainted by editorial influences. It ranks with Wikipedia, which is also not a valid reference<br /><br />The Buran was a direct copy of the US shuttle, there were no other real variants<br /><br />Height did matter, crew and payload access at the pad was an issue. <br /><br />edit:<br />Anyways, the Astronautix reference does not mention CP

 

[docm]

IMO something like the HL-20/Dream Chaser or a 6-8 passenger capsule is the way to go; big enough for crew, small enough to use a tougher TPS (SIRCA?) without too much weight and put cargo on a heavy lifter. Mixing cargo & crew and the compromises involved is what got us here.<br /><br />Just as long as you don't turn it into a procurement nightmare.<br /><br />OOPS <img src="/images/icons/tongue.gif" /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

SG, have to use this card, but do you work ELV's? No.<br /><br />Like I have said, CP behind CG is only applicable to passively guided rockets. It is not applicable to guided vehicles. All that matters is that there is sufficent control margin, which is that the control forces (gimbaled engines, aerosurfaces, thrusters, etc) are greater than the aero forces.<br /><br />Delta 178 accident is one proof. The main engine cuts off and the rocket tumbles. If CP was aft of the CG, it would have flown like an arrow. Instead, the aft end tried switching with the forward because the CP was in front of the CG.<br /><br />PS. The orbiter is unstable in some entry regimes. <br /><br />Edit: When was the last time any LV (no fins) crashed nose first? Never

 

[rocketwatcher2001]

<font color="yellow">Anyways, the Astronautix reference does not mention CP</font><br /><br />Uhm....what do you think they were testing in the wind tunnels? <br /><br />Perhaps you can enlighten this Flight Engineer for what a wind tunnel is for, because I always thought, perhaps foolishly, that it's mostly for studying aerodynamics, and I remember from day one of Flight Engineer school learning that CP is the sum of the aerodynamic forces acting on a body in flight. Actually I learned that in flight school for pilots, before I became a Flight engineer. Have I, and all of the other pilots, and Flight Engineers been taught wrong? <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

"Uhm....what do you think they were testing in the wind tunnels? "<br />total drag<br />total lift<br />interference drag<br />shock interactions<br />plume interactions,<br />flow mixing<br />etc<br /><br />There is much more to wind tunnel testing and aerodynamics than just CP location. <br /><br />That's what Aerospace Engineers learn.

 

[rocketwatcher2001]

<font color="yellow">"Uhm....what do you think they were testing in the wind tunnels? " <br /><br />total lift <br />interference drag <br />shock interactions <br />plume interactions, <br />flow mixing <br />etc <br /><br />There is much more to wind tunnel testing and aerodynamics than just CP location. <br /><br />That's what Aerospace Engineers learn. </font><br /><br />total drag = aerodynamics<br /><br />interference drag = aerodynamics<br /><br />shock interactions = aerodynamics<br /><br />shock interactions = aerodynamics<br /><br />plume interactions = aerodynamics<br /><br />flow mixing = aerdynamics<br /><br />etc ...... Sure, there is a bunch more stuff too. But what is the sum of the aerodynamic forces acting on a body in flight called? And what reason why, aerodynamicly, would the Soviets put their Orbiter nearly exactly where the Americans did? It's CP. <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

"But what is the sum of the aerodynamic forces acting on a body in flight called?" <br /><br />Sum of the aerodynamic forces. The "location" where this sum of these forces acts upon is called the Center of Pressure. CP is only used in stability calculations, it is not the end all aerodynamic factor. <br /><br />Aerdynamics does not equate to CP. <br /><br />All the things I listed do not enter in the CP computation.<br /><br />"And what reason why, aerodynamicly, would the Soviets put their Orbiter nearly exactly where the Americans did? It's CP."<br /><br />Wrong, the soviet put the orbiter where the americans did because that where americans put it and therefore it is right. Which was the same reasoning the soviets built the shuttle. If the americans are building one, then it must be right.<br /><br />

 

[rocketwatcher2001]

<font color="yellow">Wrong, the soviet put the orbiter where the americans did because that where americans put it and therefore it is right. Which was the same reasoning the soviets built the shuttle. If the americans are building one, then it must be right.</font><br /><br />No way. Did the Soviets build a Mercury, Gemini, or Apollo? No, they built what they knew made sense. The only time I can think of when the Soviets reversed engineered an American design and copied it was the TU-4 Bull, an American B-29. The SR-71 Blackbird was our mach 3 superstar, but the Soviets built theirs totally different, not out of titainium, but of stainless, and completely unlike the SR-71, it was the Mig 25. Some of their designs might look similar, but they are 100% Soviet designed. The reason they look similar, like the Blackjack to the B-1 is because it's the best aerodynamicly. Just like the Shuttle. <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

"No way. "<br /><br />Way. It has been documented over and over, the soviet built the shuttle because the US did and they followed the basic design. The US shuttle vs Buran is no where like Blackjack vs B-1. The US design is due to many compromises, which the soviets didn't need to follow but they did.