So, I worked at Hyperloop One for a time, and that experience made me skeptical of the type of complaint I see in this thread.
Yes, a high school physics student can tell you the accelerations will be huge unless the loop is too, and a smart one can explain you need a circularizing burn.
But, contrary to popular belief investors aren’t total idiots who neglect basic questions. Hard tech companies do face major challenges of course, but they aren’t the ones armchair engineers on HN can point out with 5 minutes thought.
So instead of indulging in the “hurrr it’ll never work” superiority stimulus, I’d Like to point out some rays of hope:
I don’t think “catapult” means “solid arm on an axle spinning at high speed.” I’m guessing it actually means a large-ish diameter magnetically levitated and accelerated loop. That makes much larger radii possible: at 1 mile you’re looking at ~300g acceleration, 150g at 2 mile. We have loops much bigger than this with much more complex magnetics and vacuum components in our particle accelerators, so this wouldn’t be terrifyingly novel tech.
Those accelerations are big but not horribly painful to make a smallsat stand up to. We have guided artillery shells that bear 15,000g launches.
I think it’s somewhat feasible. I also think big fully reusable chemical rockets will beat this thing on cost and ease of use, but i don’t think it’ll fail because of armchair physics.
>But, contrary to popular belief investors aren’t total idiots who neglect basic questions
Investors, particularly tech investors often do neglect basic (tech DD) questions.
Sometimes it’s because they’re investing in the “team” and neglect DD. Sometimes it’s because the area is hot and they need to make a play... or just because they happen to know or like the people involved.
Whatever the reason, it’s dangerous to assume that the investors must have done their DD (see Theranos for example). Not saying that this is the case here, and often things work out anyway...
> We have loops much bigger than this with much more complex magnetics and vacuum components in our particle accelerators, so this wouldn’t be terrifyingly novel tech
Last cost estimate I saw for a reasonably-sized slingshot was $10 billion, which is in the neighbourhood of the LHC's €7.5 billion accelerator + accoutrements cost [1].
Some of the skepticism in this thread, particularly regarding the technology's core viability, is premature. But economic scepticism is warranted. I would be skeptical of a space elevator project without mass-manufactured carbon fibre; I am skeptical of a slingshot proposal without cheap superconductors.
This doesn't seem impossible. There are some PoCs to be found in old technology.
The shock loads are surmountable. We made an atomic bomb that worked after enduring at least 10KG acceleration. [1]
The aero loads (mechanical and thermal) also seem feasible. We built guided interceptors that launched from sea level and accelerated at 100G to over 7,000 mi/hr. [2] These endured incandescent skin temps within a few seconds of flight.
Aero drag loads can be mitigated mechanically. The aerospike on the Trident missile shows one way of reducing drag by putting a small mechanical probe ahead of the vehicle. [3]
No idea about the economics, but I wish them every success.
Indeed! Assuming that your centripital accel. numbers are right, I wonder why not even just use linear accel.
Assuming that you want to exit the tube/system at 5000mph, you could keep acceleration to 9g (tolerable for a human)with less than a 9 mile long acclerator and 18 seconds. If you were ok with 40g, you're down under 4miles and 6 seconds.
(I'm not estimating the deceleration Gs from suddenly hitting MaxQ on exiting into the lower atmosphere. So perhaps that shock puts us up into a high G situation anyway, so might as well go for the smaller real-estate circular acceleration option?)
edit: "tolerable for a human" might better read "survivable for trained humans"
Converting everything to metric and working out the centripetal acceleration, a radius of 1 mile yields a centripetal acceleration of 232g, to an arbitrary 3 significant figures. A radius of 2 miles yields 116g. The acceleration would drop linearly along the length of the "arm" as you move toward the center, so you could calculate (with calculus, over which I can't be bothered at the moment) the optimal way to taper the arm from root to tip for a given end load.
Drag losses on the arm at a 1 or 2 mile radius would dominate, and ridiculously so. Frankly, roughly 100-230g is not severe at all for a properly engineered vehicle at the payload ratio you could expect to achieve if you get the first 2.2 km/sec "free", as you would in this scheme. That's the majority of a factor of exhaust velocity for a kerosene/lox engine, and all of a factor of the exhaust velocity for a solid rocket motor. Multiples of exhaust velocities are factors of e, so you're probably better than doubling the payload ratio. Perhaps counterintuitively, going from 3 percent mass fraction to 6 percent brings your vehicle size down by half. You go from ~33 times the payload to ~16 times the payload. And, while others are talking a good game about drag, this saves you loads in gravity losses, as the rocket is spending far less time fighting gravity with this initial boost. (1g for two minutes is 1.2 km/s, give or take centripetal effects from your curved launch trajectory. Not negligible, at all.) The other commenters seem also to be mostly neglecting that the motor/engine will very quickly reach near-vacuum conditions, not immodestly increasing its ISP.
Much better than a mile-long tether would be, in my not-so-humble initial opinion, to reduce the tether length by a factor of 10 or 100 from "a mile", to give a centripetal g load of 2k-20k g. Again, calculus tells you how to taper your (probably carbon fiber, possibly consumable, most definitely streamlined) attachment rod. And don't bother with the complexity of a vacuum. The Nike program launched vehicles at Mach 10 in the lower atmosphere. That's 3.4 km/s, 1.2 km/s faster than SpinLaunch's proposal. Given that heating goes something like the 4th power of velocity, Mach 6 or so is going to be much, much less severe than the Mach 10 environment encountered by Nike. Why, SpinLaunch vehicles won't even get to glow white hot!
> at 1 mile you’re looking at ~300g acceleration, 150g at 2 mile.
Could you explain? Centripetal acceleration is v^2/r, so naively I'd think something moving at LEO orbital velocity in a radius of 1 mile requires ~4,000g because LEO has a radius ~4k miles under 1g.
One question I've never been able to figure out with this concept is what happens when this fast moving launch vehicle hits the stationary air. Would it be like hitting a wall? I'm a bit physics ignorant.
Long ago I heard that the reason why the Jules Verne space cannon was infeasible was not so much the acceleration as the aerodynamics; 5000mph is "hypersonic". I'm not quite clear whether the spinlauncher's rocket is just for circularisation or whether it's needed to clear the atmosphere too?
Why are you skeptical? HN community always been this negative, or even more! Remember the initial Drew's DropBox idea that majority bashed him that its a stupid idea because... everyone would rather built its own software? Drew Stock in Drop is $1B worth right now.
If anything, I think its opposite - the more HNers are negative the more your idea has a strong standing!
Coincidentally, on the subject of catapults, just recently I was bashed by "always_good" that "I'm sure a bunch of children also wonder the same thing" [1]
The tyranny of Tsiolkovsky's rocket equation [1] results from the need to burn fuel now to accelerate fuel for later. "Catapulting" sidesteps this issue by energizing on the ground.
In selling away the rocket equation you buy yourself drag. Lots of energy up front means lots of drag. Overcoming that drag means more energy and, hence, more drag. The middle child of this solution is tremendous G force.
You can't slingshot complex things into space. Pretty much just fuel and raw materials. That means you need in-space (a) refueling and (b) additive manufacturing capabilities. There are teams working on both problems, though they are presently in the domain of science versus engineering. Perhaps that will now be incentivized to change.
1) accelerate fast enough to penetrate the atmosphere at high speeds (and remember, the faster you travel, the air resistance is the square of your velocity).
2) withstand the crazy max-q as soon as you leave the spiral (which I assume is vacuumed).
3) make the centrifugal forces reasonable during the acceleration
The article mentions acceleration to 5000mph, which would be enough if there was no atmosphere, but I highly doubt it will work with.
> In selling away the rocket equation you buy yourself drag. Lots of energy up front means lots of drag. Overcoming that drag means more energy and, hence, more drag. The middle child of this solution is tremendous G force.
Would it be possible and useful to do it with a 2 payloads system: one dumb piece of material first which can take lot of G followed closely by your "fragile" payload using its draft?
I'm very skeptical, of course I'm not as smart or as informed as many other people so what I'm saying might not mean anything.
1) if the idea is to impart all of the kinetic energy needed to get into LEO at once, on the ground, then you are talking ~17,000 MPH worth of KE (though truly, more, because of loss to drag). There's a reason why max-q is an important consideration in the design of space vehicles. The space shuttle reaches max-q at 30K feet, where the density of air is 3x less than at sea level. How do you design your vehicle so that it doesn't turn into dust when it hits 1 ATM at 17,000+ MPH?
2) the centripetal force on the vehicle, prior to launch, will be enormous. So in addition to not deforming and/or burning up the moment the vehicle hits the air, the vehicle also needs to be built sturdily enough to not get crushed while being accelerated.
I read Bad Blood a few weekends ago. Holmes hoodwinked investors who wanted to believe that a fairy tale technology could exist, by never publishing or otherwise allowing outside scrutiny of their technology. How is this company different?
> So in addition to not deforming and/or burning up the moment the vehicle hits the air, the vehicle also needs to be built sturdily enough to not get crushed while being accelerated.
Since launch mass is less of a concern maybe they can just manufature the satellites differently, e.g. filling the voids with a resin or oil which distributes the forces uniformly.
Years ago I backed the Slingatron [0] on Kickstarter, but sadly it was not funded. At first I thought maybe SpinLaunch was a rebrand of HyperV, but that is not the case and its an entirely different group of people. Either way, I'm glad this is getting actual money behind it since it's a very interesting solution, and I hope it "takes off" (sorry).
It’s surprising how many ways there are to get things into space. Everyone seems to assume we’ve already considered all alternatives and rockets are all we have.
This is just total lunacy. Have we reached peak VC yet? If not I have a startup that is building a warp drive even though its totally theoretical and the technology to build one is 100+ years away. Throw money at me please.
I’ve wanted to build a Gerald Bull style space cannon (but the more modern UW RAMAC style) for a long time. Prototype would be $2-5mm, something small which could actually put something decent into orbit around $50mm. I’ve heard there is a group in SoCal which finally got funding to build it.
Would love to know more if you have a link about this group. For some reason I'm fascinated by the space gun concept. Even if it were only used to launch raw materials into space cheaply that could still be a huge boost to space exploration.
I wonder what the flight path would have to look like - I assume you wouldn't be able to accelerate in a circle on the ground and then tilt upwards because of the G force of the tilt. So you would either sling horizontally at a fairly slight incline (taking advantage of the curvature of the earth, but imagine keeping that flight path clear), have a slowly increasing ramp that would probably have to be really long to manage the G force, or accelerate in a vertically-oriented loop (which would have to be huge to cope with faster speeds). I'm guessing the slow ramp is most practical.
If the radius of the ramp is the same as the loop wouldn’t it experience the same acceleration once diverted to the ramp? (but in a different direction)
I would love to see these guys succeed both because it would be something truly novel, and because I think low cost access to space is going to be critical moving forward.
But the physics of getting through the troposphere at 7 to 9 km/sec seem to be really difficult to overcome.
There is a lot of published raw science on Electromagnetic Linear Motors, with several feasibility studies on Earth to Orbit and Earth to Moon systems.
There are several challenges with building on that large, such as building large capacitors, building a structure big enough, and dealing with something that high energy. However, I think we are at a critical point where this might become something we understand how to build. We use the fundamental technology everyday in high speed rail, and we've learned a lot from constructing projects like the LHC and Hyperloop. The Navy is planning on implemented these motors for launch assist on the next generation of aircraft carriers.
The article is very light on details, but I believe what's being proposed is an evacuated tube with maglev propulsion, used to accelerate a rocket up to 5000mph (as stated in the article) while on the ground. The rocket is then released, and travels until some altitude is reached, at which point engine then starts and it continues to orbit. This results in a large fuel saving over a conventional rocket.
The g-forces involved would be very high, well beyond lethal to a human, so this would be for launching robust satellites, raw materials, or fuel cheaply into space. They would still be substantially lower than those of a space gun / intercontinental artillery.
Kind obvious solution when you loop the idea of long gun launch into a fast spinning ferris wheel. Much easy and simpler power delivery. Centripetal acceleration bites though.
I've been exploring large-scale structures built using the "Tensegrity" concepts of Bucky Fuller and Ken Snelson. I'm pretty sure you can build really large structures using modern materials (e.g. kevlar and carbon fiber.) Call it "giga-tech" (like nano-tech but scale up instead of down.)
One thing in particular that seems feasible is a large floating structure, like a mile-high pyramid, placed on an ocean at the equator, and supporting a launch structure.
I think you can make a very large whip-like jointed spaceframe that acts like a catapult to accelerate payloads.
By enclosing the outer surface with a membrane you can use solar energy to evaporate water, then condense it at the top of the structure into holding tanks. The mass of the water powers the whip like a trebuchet. (Or you can extract electricity using the principle of Lord Kelvin's Thunderstorm.)
I'm pretty sure it would work. No advanced technology or concepts used at all. I don't quite have the chops to do the back-of-envelope math though. Right now I'm working on computer simulations (Finite Element Method.) I'm fortunate that NASA has a program working on tensegrity robots for exploring the surfaces of other planets, and they have released a tool that can simulate tensegrity structures.
One other thing, in re: rockets and drag. I can't find a reference right now, but electrifying a rocket with a charge difference from the nose to the tail can significantly reduce drag as the field accelerates the air itself.
[+] [-] nickparker|7 years ago|reply
Yes, a high school physics student can tell you the accelerations will be huge unless the loop is too, and a smart one can explain you need a circularizing burn.
But, contrary to popular belief investors aren’t total idiots who neglect basic questions. Hard tech companies do face major challenges of course, but they aren’t the ones armchair engineers on HN can point out with 5 minutes thought.
So instead of indulging in the “hurrr it’ll never work” superiority stimulus, I’d Like to point out some rays of hope:
I don’t think “catapult” means “solid arm on an axle spinning at high speed.” I’m guessing it actually means a large-ish diameter magnetically levitated and accelerated loop. That makes much larger radii possible: at 1 mile you’re looking at ~300g acceleration, 150g at 2 mile. We have loops much bigger than this with much more complex magnetics and vacuum components in our particle accelerators, so this wouldn’t be terrifyingly novel tech.
Those accelerations are big but not horribly painful to make a smallsat stand up to. We have guided artillery shells that bear 15,000g launches.
I think it’s somewhat feasible. I also think big fully reusable chemical rockets will beat this thing on cost and ease of use, but i don’t think it’ll fail because of armchair physics.
[+] [-] xevb3k|7 years ago|reply
Investors, particularly tech investors often do neglect basic (tech DD) questions.
Sometimes it’s because they’re investing in the “team” and neglect DD. Sometimes it’s because the area is hot and they need to make a play... or just because they happen to know or like the people involved.
Whatever the reason, it’s dangerous to assume that the investors must have done their DD (see Theranos for example). Not saying that this is the case here, and often things work out anyway...
[+] [-] JumpCrisscross|7 years ago|reply
Last cost estimate I saw for a reasonably-sized slingshot was $10 billion, which is in the neighbourhood of the LHC's €7.5 billion accelerator + accoutrements cost [1].
Some of the skepticism in this thread, particularly regarding the technology's core viability, is premature. But economic scepticism is warranted. I would be skeptical of a space elevator project without mass-manufactured carbon fibre; I am skeptical of a slingshot proposal without cheap superconductors.
[1] https://en.wikipedia.org/wiki/Large_Hadron_Collider#Cost
[+] [-] mmphosis|7 years ago|reply
Thank you.
[+] [-] ridgeguy|7 years ago|reply
The shock loads are surmountable. We made an atomic bomb that worked after enduring at least 10KG acceleration. [1]
The aero loads (mechanical and thermal) also seem feasible. We built guided interceptors that launched from sea level and accelerated at 100G to over 7,000 mi/hr. [2] These endured incandescent skin temps within a few seconds of flight.
Aero drag loads can be mitigated mechanically. The aerospike on the Trident missile shows one way of reducing drag by putting a small mechanical probe ahead of the vehicle. [3]
No idea about the economics, but I wish them every success.
[1] https://en.wikipedia.org/wiki/M65_atomic_cannon [2] https://en.wikipedia.org/wiki/Sprint_(missile) [3] https://en.wikipedia.org/wiki/Drag-reducing_aerospike
[+] [-] lainga|7 years ago|reply
https://en.wikipedia.org/wiki/Momentum_exchange_tether
[+] [-] toss1|7 years ago|reply
Assuming that you want to exit the tube/system at 5000mph, you could keep acceleration to 9g (tolerable for a human)with less than a 9 mile long acclerator and 18 seconds. If you were ok with 40g, you're down under 4miles and 6 seconds.
(I'm not estimating the deceleration Gs from suddenly hitting MaxQ on exiting into the lower atmosphere. So perhaps that shock puts us up into a high G situation anyway, so might as well go for the smaller real-estate circular acceleration option?)
edit: "tolerable for a human" might better read "survivable for trained humans"
[+] [-] theothermkn|7 years ago|reply
Drag losses on the arm at a 1 or 2 mile radius would dominate, and ridiculously so. Frankly, roughly 100-230g is not severe at all for a properly engineered vehicle at the payload ratio you could expect to achieve if you get the first 2.2 km/sec "free", as you would in this scheme. That's the majority of a factor of exhaust velocity for a kerosene/lox engine, and all of a factor of the exhaust velocity for a solid rocket motor. Multiples of exhaust velocities are factors of e, so you're probably better than doubling the payload ratio. Perhaps counterintuitively, going from 3 percent mass fraction to 6 percent brings your vehicle size down by half. You go from ~33 times the payload to ~16 times the payload. And, while others are talking a good game about drag, this saves you loads in gravity losses, as the rocket is spending far less time fighting gravity with this initial boost. (1g for two minutes is 1.2 km/s, give or take centripetal effects from your curved launch trajectory. Not negligible, at all.) The other commenters seem also to be mostly neglecting that the motor/engine will very quickly reach near-vacuum conditions, not immodestly increasing its ISP.
Much better than a mile-long tether would be, in my not-so-humble initial opinion, to reduce the tether length by a factor of 10 or 100 from "a mile", to give a centripetal g load of 2k-20k g. Again, calculus tells you how to taper your (probably carbon fiber, possibly consumable, most definitely streamlined) attachment rod. And don't bother with the complexity of a vacuum. The Nike program launched vehicles at Mach 10 in the lower atmosphere. That's 3.4 km/s, 1.2 km/s faster than SpinLaunch's proposal. Given that heating goes something like the 4th power of velocity, Mach 6 or so is going to be much, much less severe than the Mach 10 environment encountered by Nike. Why, SpinLaunch vehicles won't even get to glow white hot!
[+] [-] jessriedel|7 years ago|reply
Could you explain? Centripetal acceleration is v^2/r, so naively I'd think something moving at LEO orbital velocity in a radius of 1 mile requires ~4,000g because LEO has a radius ~4k miles under 1g.
[+] [-] hangonhn|7 years ago|reply
[+] [-] astrodust|7 years ago|reply
[+] [-] madeuptempacct|7 years ago|reply
[deleted]
[+] [-] buvanshak|7 years ago|reply
You just lost your credibility.
[+] [-] pjc50|7 years ago|reply
[+] [-] joering2|7 years ago|reply
If anything, I think its opposite - the more HNers are negative the more your idea has a strong standing!
Coincidentally, on the subject of catapults, just recently I was bashed by "always_good" that "I'm sure a bunch of children also wonder the same thing" [1]
[1] https://news.ycombinator.com/item?id=17174196
Edit: made it less personal :)
[+] [-] JumpCrisscross|7 years ago|reply
In selling away the rocket equation you buy yourself drag. Lots of energy up front means lots of drag. Overcoming that drag means more energy and, hence, more drag. The middle child of this solution is tremendous G force.
You can't slingshot complex things into space. Pretty much just fuel and raw materials. That means you need in-space (a) refueling and (b) additive manufacturing capabilities. There are teams working on both problems, though they are presently in the domain of science versus engineering. Perhaps that will now be incentivized to change.
[1] https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
[+] [-] kuprel|7 years ago|reply
[+] [-] bufferoverflow|7 years ago|reply
1) accelerate fast enough to penetrate the atmosphere at high speeds (and remember, the faster you travel, the air resistance is the square of your velocity).
2) withstand the crazy max-q as soon as you leave the spiral (which I assume is vacuumed).
3) make the centrifugal forces reasonable during the acceleration
The article mentions acceleration to 5000mph, which would be enough if there was no atmosphere, but I highly doubt it will work with.
[+] [-] arkh|7 years ago|reply
Would it be possible and useful to do it with a 2 payloads system: one dumb piece of material first which can take lot of G followed closely by your "fragile" payload using its draft?
[+] [-] tomp|7 years ago|reply
[+] [-] edmundhuber|7 years ago|reply
1) if the idea is to impart all of the kinetic energy needed to get into LEO at once, on the ground, then you are talking ~17,000 MPH worth of KE (though truly, more, because of loss to drag). There's a reason why max-q is an important consideration in the design of space vehicles. The space shuttle reaches max-q at 30K feet, where the density of air is 3x less than at sea level. How do you design your vehicle so that it doesn't turn into dust when it hits 1 ATM at 17,000+ MPH?
2) the centripetal force on the vehicle, prior to launch, will be enormous. So in addition to not deforming and/or burning up the moment the vehicle hits the air, the vehicle also needs to be built sturdily enough to not get crushed while being accelerated.
I read Bad Blood a few weekends ago. Holmes hoodwinked investors who wanted to believe that a fairy tale technology could exist, by never publishing or otherwise allowing outside scrutiny of their technology. How is this company different?
[+] [-] the8472|7 years ago|reply
Since launch mass is less of a concern maybe they can just manufature the satellites differently, e.g. filling the voids with a resin or oil which distributes the forces uniformly.
[+] [-] istjohn|7 years ago|reply
[+] [-] binarymax|7 years ago|reply
[0] https://www.kickstarter.com/projects/391496725/the-slingatro...
[+] [-] mrfusion|7 years ago|reply
Off the top of my head:
Providing laser power from the ground station
Giant rail gun
Launch fountain
Launch loop
Space elevator
Sky hook
This spin machine
[+] [-] rossjudson|7 years ago|reply
A giant torus that floats near the edge of the atmosphere. Spin it for more lift, stability, and to throw things.
;)
[+] [-] JoeAltmaier|7 years ago|reply
[+] [-] jimbofisher1|7 years ago|reply
[+] [-] sharemywin|7 years ago|reply
[+] [-] rdl|7 years ago|reply
[+] [-] growlist|7 years ago|reply
[+] [-] beaconstudios|7 years ago|reply
Either way, there's some interesting info on the concept at https://en.wikipedia.org/wiki/Space_gun and https://en.wikipedia.org/wiki/Mass_driver.
[+] [-] tlrobinson|7 years ago|reply
[+] [-] dforrestwilson|7 years ago|reply
Every time that an object leaves our planet’s atmosphere we (apparently) minutely change the earth’s orbit.
https://space.stackexchange.com/questions/26733/does-launchi...
[+] [-] astrodust|7 years ago|reply
[+] [-] ChuckMcM|7 years ago|reply
But the physics of getting through the troposphere at 7 to 9 km/sec seem to be really difficult to overcome.
[+] [-] lev99|7 years ago|reply
There are several challenges with building on that large, such as building large capacitors, building a structure big enough, and dealing with something that high energy. However, I think we are at a critical point where this might become something we understand how to build. We use the fundamental technology everyday in high speed rail, and we've learned a lot from constructing projects like the LHC and Hyperloop. The Navy is planning on implemented these motors for launch assist on the next generation of aircraft carriers.
[+] [-] shashanoid|7 years ago|reply
[+] [-] piker|7 years ago|reply
[+] [-] Maybestring|7 years ago|reply
[+] [-] zer0faith|7 years ago|reply
[+] [-] gnode|7 years ago|reply
https://en.wikipedia.org/wiki/Mass_driver
The g-forces involved would be very high, well beyond lethal to a human, so this would be for launching robust satellites, raw materials, or fuel cheaply into space. They would still be substantially lower than those of a space gun / intercontinental artillery.
https://en.wikipedia.org/wiki/Space_gun#Practical_attempts
[+] [-] trhway|7 years ago|reply
[+] [-] Dowwie|7 years ago|reply
[+] [-] unknown|7 years ago|reply
[deleted]
[+] [-] JohnClark1337|7 years ago|reply
[deleted]
[+] [-] carapace|7 years ago|reply
One thing in particular that seems feasible is a large floating structure, like a mile-high pyramid, placed on an ocean at the equator, and supporting a launch structure.
I think you can make a very large whip-like jointed spaceframe that acts like a catapult to accelerate payloads.
By enclosing the outer surface with a membrane you can use solar energy to evaporate water, then condense it at the top of the structure into holding tanks. The mass of the water powers the whip like a trebuchet. (Or you can extract electricity using the principle of Lord Kelvin's Thunderstorm.)
I'm pretty sure it would work. No advanced technology or concepts used at all. I don't quite have the chops to do the back-of-envelope math though. Right now I'm working on computer simulations (Finite Element Method.) I'm fortunate that NASA has a program working on tensegrity robots for exploring the surfaces of other planets, and they have released a tool that can simulate tensegrity structures.
One other thing, in re: rockets and drag. I can't find a reference right now, but electrifying a rocket with a charge difference from the nose to the tail can significantly reduce drag as the field accelerates the air itself.