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Lean-V — Space Shuttle Design
Published: 2009-02-04 02:52:08 +0000 UTC; Views: 3990; Favourites: 29; Downloads: 0
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Description
I'm involved in the High School Aerospace Scholars program for NASA and we had to design and draw a new CEV (Crew Exploration Vehicle) that would replace the current space shuttle for one of our assignments.Naturally, my brain was exploding in glee and my mind was in a euphoric state when I learned of the assignment- I rock at drawing only 2 things- machines and SPACE SHIPS (although it did feel a little weird to draw a space vehicle that wasn't loaded to the brim with weapons and guns...)
This is the result- done with HB pencils, .08mm pens, and an abundance of planning. If you have any questions about the technicalities, feel free to just ask
.By the way- my second graphic is also online: Space Maneuvering System
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Comments: 16
If you still have that essay, I'd love to read it.
Could you send it to me at hollowsunsets@hotmail.com?
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It's on an old computer that's out of reach at the moment, sorry. =/
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HOLY CRAP! How did you get an assignment LIKE THAT!? I WANT IT!
Really, though, I'd absolutely die of excitement if I ever got an opportunity to propose a system to replace the STS.
Personally, my design would involve two aerodynamic vehicle stages, it has the advantage of an SSTO; namely, the entire thing can take off and land on a runway, yet it also has the necessary boost of staging that's required to get enough Delta-Vee to reach orbit.
Oh dear gosh, I would die if I got this as an assignment. I have to do pan out this design some time...
Q: So, this is an SSTO?
2: What's the mass ratio of both the SRB's (Ammonium Perchlorate) and SSME's (LOX-LH2), each?
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Q: "So, this is an SSTO?"
Yes! At least this was the idea. It takes the shape of flying wing to maximize lift while minimizing cross-section (smaller cross-section SHOULD assist the structural integrity during re-entry due to less air resistance).
Q: "What's the mass ratio of both the SRB's (Ammonium Perchlorate)"
The mass ratios for both the ammonium perchlorate and LOX were both planned to mimic those used for the STS- whether this is sufficient for this given scenario I have absolutely no idea. This honestly wasn't a detail I gave too much thought during its design.
Again, I don't have a degree (yet) so this is all according to the cerebral drafting table 
In any case, thanks for the support and I'm always glad to see another Space enthusiast!
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Re-entry is actually really interesting and isn't quiet intuitive. You actually want more air resistance, though your design would be good for reducing structural mass needed because the shape is inherintly stronger. I can also see how it creates a large internal volume to allow for a high mass ratio despite being an aerodynamic SSTO.
See the X-33 Venture Star; large internal volume, as any SSTO would need to hold it's payload, crew, and high mass ratio of fuel.
(X-33 is the scaled-down model they built to test the new heat shield technology, Venture Star is the SSTO's name, though X-33 was part of the Venture Star project.)
[link]
Reentry:
[link]
Some things it doesn't mention is the re-entry itself. I wouldn't describe it as flying in S-shape patterns, there's a better way to describe it, but requires some more info on re-entry aerodynamics, which it doesn't touch on.
So, since re-entry is at mach 27, air flow is at a very narrow angle (the shockwave cone, that is). In order to get lift, air must be flowing over the entire surface of the wing shape. If you pitch up too high at too fast of a speed, the air will "detach" from the upper surface of the wing, and the wing won't generate lift. (Ah, just found the correct term is "Flow Separation" [link] )
Normally, at everyday speeds, flow separation is somewhat rare and not much of a problem, except in highly maneuverable aircraft. But at Mach 27, the STS Orbiter will get most of it's lift somewhere around 12 degrees Angle of Attack (AoA) (since it's travelling so quickly, for most of re-entry Angle of Attack is synonamous to pitch, if the Yaw is 0). At the 40* re-entry angle (it never leaves the range of 25-45*) a huge portion of it's lifting surface is separated, or detached, so that it's not forming it's full lift, and instead, is creating a lot of drag. As it pitches lower, less air surface is detached, so it creates more lift. So, counterintuitively, as it decreases AoA, or pitches down, levels the nose, it gets more lift, and goes up. This continues until it's entire wing is "attached", which is about at 12*, though it never even pitches down to 25* during re-entry.
Now, as your pitch goes lower, it increases lift, but also increases drag (alas, lift is a form of drag), so you slow down faster. You want lots of drag(/lift) to slow you down as much as possible, higher drag, shallower angle means you'll slow down faster, slower speed as you hit lower and lower atmosphere means less heat. More drag/lift, less heat.
But, what if you want to increase drag, but you don't want to increase vertical speed (aka climb)? You lower the nose, but you yaw so the lift pulls you sideways and the vertical Y-component isn't as large, so you don't change your vertical speed as much. After you go right, you have to go left to stay on course, so I think from the pilot's perspective "Yawing" would be a more appropriate way to say it than S-patterns, but requires a little more depth knowledge to understand.
The reason all lifting spacecraft have Delta-Wings (at least all those that are designed for de-orbiting re-entry, non-orbital spacecraft travelling at a much lower speed like SpaceShipOne don't need to re-enter...) is because of the re-entry process. As you pitch up, the longer wing surfaces closer to the center of the delta-wing get flow separation and stop producing lift, however, the shorter wing surfaces closer to the tip continue to produce lift at an angle where the longer air surfaces don't.
Imagine if the wing for the "flow separation" image on wiki was shorter. You can see how air would stick to the upper side and create lift more readily if it was smaller and more circular, the wingtips on a Delta wing are smaller than near the body of the aircraft, so that as you pitch up in the shuttle, you gradually lose lift.
(A bit more in depth: a flat line will obviously separate at a very shallow angle. A circle will be much harder to seperate from air flow. Since the wings don't get significantly thinner near the tips, but get much shorter, they get closer to a circle shape, so it's more difficult to separate the airflow. So the wingtips produce lift while the longer part of the wing doesn't.)
(Aside, On the shuttle, you notice two delta-wing shapes merged, one with a very shallow angle and one very steep, the narrow one closer to the body is detached through re-entry, and only provides lift for the gliding, aircraft-like flight portion. It's really quiet ingenious, extra lift for aircraft flight that doesn't interfere with the re-entry portion of the flight.)
But, a wing design without a delta-wing, where the wing length and shape is the same over the entire wing structure, would lose lift for the entire wing all at one angle, making re-entry descent rate control impossible, and so you'd re-entry more like a capsule than the STS orbiter, which would null the purpose of having an aerodynamic design in the first place.
Also, my guess is you'd need a much higher mass ratio; for two reasons:
#1. In an SSTO design you don't shed the excess mass with staging, so naturally you need a much higher mass ratio. In the X-33/Venture Star program, an SSTO project, with Vertical Takeoff-Horizontal Landing (VTHL) like the STS, A much higher mass ratio was needed and only LOX/LH2 engines were used for their high impulse. In fact, the Venture Star was to use Aerospike nozzles to raise the specific impulse even higher, all three of these factors were needed to make an SSTO work.
#2. The STS is very long for it's width because of the equation for aerodynamic drag: a direct factor is the forward surface area, higher forward surface area means much higher drag. You want aerodynamic drag for re-entry, but not for takeoff.
I'm sorry I'm evil
SSTO is a concept that many countries have been chasing after for many decades with dozens of concepts, and never once has succeeded (Well, actually, it has, but that was for a non-reusable, non-aerodynamic rocket. The non-aerodynamic shape makes it much simpler to get a much higher mass ratio Nobody, anywhere, seems to realize this, though).
But anyways, an aerodynamic OR reusable SSTO has never before been created, and it's been tried so many times that it's almost regarded as scam territory, because so many SSTO projects have failed.
I want to read the essay if you can find it
1200 word is alright, as long as it's not 1200 page
Hmm. I should work on my 2-stage aircraft concept
@ Sig: I get a feeling you haven't read Mere Christianity by C.S. Lewis. The argument's a bit more involved than that, and anyways, there's a lot more pressure to not believe in a God, because if there wasn't, then there would be Moral Relativism and I could do a lot of things and live for today and not worry about tomorrow.
But... I don't speak for everyone that's religious. Very few of them go as deep or question things like I do
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i have another question
where are the airlocks?
or do the emergency bail out doors double as airlocks?
or is it used only for missions that do not require anyone to go outside of the craft or dock with anything?
i guess technically thats three questions
sorry if i am becoming irratating
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Oh, and as part of this assignment, I had to write a 500 word essay (I hit 1,200) Explaining the shuttle and most of its systems. If you feel inclined to read the lengthy-ish essay, I feel that it would answer some further questions and clear some things up for you. If you wish to read it, I'll need your e-mail and I guarentee that it'll be in your inbox within 10hours. (there seems to be roughly a 8hr delay in our messages...)
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I would love to take a look at your essay Lean-V.
These types of projects are truly inspiring!
~Cheers,
AT.
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I don't think I have it anymore actually. I've moved since then, and the computer it was saved on is in a storage unit at the moment, sorry.
Thanks for showing interest though.
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thanks for the essay
it is very impressive undoubtably you got an A for it
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I got a 93 on it. Only reason I lost points was because I forgot a work cited page 
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i would very much like to read your essay please send to
connorlockyer@yahoo.com
btw there is a -6 hour time difference from me to you (im on greenwich meridian time)
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Great Questions! And don't think yourself as irritating, infact its rather exciting to explain my design
After pondering your set of questions for a couple minutes, I've come up with some answers! (that actually SOUND legitimate.) When mentioning a spaceshuttle, it only makes sense that there would be an airlock for the mission specialists to perform EVA's (aka space walks) from. Although intended for emergency mid ascent/descent bailout, I don't see why the bail out doors couldn't double as the necessary airlocks.
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the design seems sound and to be honest very cool but how does it steer ? i cannot see nor are there labled any manurvering thrusters
nor are there any rudders or alerons for in-atmosphere manouvering unless the thrusters tilt or are able to be pointed in different direction but even then you need at least some deceleration thrusters. but im not a space shuttle engineer any of those abreaviations could be what im twaddling on about just tell me if im being stupid
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Thanks for the favorite, and allow me to clear some things up for you
- Humans are prone to make errors, and I feel like an ABSOLUTE idiot... The parts (falsely) labeled as CEV ports are actually supposed to be labeled as RCS's (Reaction Control Systems) and THEY are the orbital maneuvering thrusters that you thought I had been lacking. Their strategic placement around the craft enable it to strafe, pitch, roll, and yaw. Although named incorrectly, the placement for the RCS's are exactly the same.
-For atmospheric return, the shuttle actually uses its forward placement RCS ports to slow it down upon re-entry
-SRB stands for Solid Rocket Boosters and are used for orbital entry- without them it would be impossible to break Earth's tenacious atmosphere
-SSME stands for Space Shuttle main engines. Although they only assist the Solid Rocket Boosters during ascent, they are the primary thrusters during missions.
-As for Aerodynamics and your mention for rudders or alerons, the shuttle flys exactly like the B-2 Spirit and flys w/o vertical stabilizers, and upon re-entry it only glides to earth and has no use for thrusters (I'm not making this up). As for air brakes or the such, the RCS's take that duty because any movement or break of the Ablative tiles will cause the whole thing to go up in flames (exactly what happened to Space Shuttle Columbia)
Again, thanks for the favorite and I hope I elucidated the whole thing for you! If you have any more questions about it, the design, or functions, feel free to ask.
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thanks for clearing that up for me
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