The latest Armadillo Aerospace project update has the usual detailed technical descriptions of engine and other vehicle work. At the end, though, John Carmack includes some illustrations of a proposed single-person suborbital vehicle, using a “six pack” of modules. Carmack talked about this concept last year at Space Access ’07, including the transparent bubble where the passenger would lie (and float around at apogee). Here’s one illustration:
Carmack warns not to “read too many technical details into these concept renderings”, but it still looks pretty interesting. Half the Armadillo team will be at Space Access ’08 to provide more details on this concept and their other work.
I wonder if it’s Jodie Foster in that pressure suit…
WOW, that’d be quite an experience sitting in there. Cool concept too integrating their developed motor/tanks into a cluster.
Hate to be the jerk who disregards the advice not to read into the tech details too much but I am curious about a few things. Aerodynamics, reentry and landing. I’m guessing reentry would be bottom down and restarting the motors at some point for a controlled landing, possibly with parachutes as well? What can I say, it’s fun to speculate!
Jodie Foster, HA! You crack me up Chris. Hey they could sell scale models as fish tanks!
oh d**n! I want one!
Let’s see
1) no Gear
2) Someone needs to give john a book on aero-drag
3) acrylic makes a poor structural element
The landing gear is just rubber pads under the tanks, actually visible in the renderings (bigger than real life). This is something we have direct experience with over the last year — landing gear that looks anything like “legs” is very heavy, and the tanks are already the strongest element of the vehicle. When we crashed Texel a while back, we discovered that if we had just had a rubber pad directly on the tank bottoms instead of the little metal foot pods, it would have survived the 20′ drop without rupturing anything.
A computer controlled VTVL is either going to land very softly around the programmed descent rate of a couple m/s, or it is going to crash. There isn’t much in the middle worth trying to optimize for with big and heavy energy absorbing devices. We have actually flown vehicles with hydraulic shocks, wire rope isolators, foam blocks, and crushable sections. This is one of the strong design points of the six pack.
As pictured, the vehicle can be transported over-the-road on a lowboy trailer without concerns about bridges, wide load permits, or erection for launch. That is a real win, and people that advantages like that aren’t working with real systems. The aspect ratio of the modules and cabin are around the minimum of what we are comfortable with for robust powered landing, but it is conceivable that the sphere could grow a pointy hat if we need to mitigate drag somewhat.
However, there is a good chance it isn’t necessary. While a “propellant optimal” flight to 100km involves about a 60 second burn time and a streamlined shape, you can get to 100km and never exceed an effective airspeed of 300 mph with a 90 second burn time. Going slower at the start and holding more delta-v for flight when the air is thinner is a reasonable design trade if it helps with other operational issues. The “wasted” propellant is cheap, and our vehicles have better mass ratios than many other designs.
It would be nice if we had transparent aluminum or some such thing, but acrylic has certainly been used as structural elements in bathyspheres and other places. We aren’t going to use anything that thick, and it is possible that we may choose to have transparent gores in a metal framework, but those are all just questions of mass, which turn into questions of propellant, which again, is cheap.
The ascent will not be a problem with
The comment was truncated a bit:
The ascent will not be a problem with
One more time, without a less-than sign…
The ascent will not be a problem with under 300 mph effective air speeds, but I do have some concerns about reentry. We should be base first stable, the engine igniters will be keeping the vehicle oriented, and there will be a backup orientation drogue, but it is the biggest unknown that we still have to get experience with. With an inexpensive design, we can afford to fly it and find out.
John,
What about polycarbonate for the bubble? I’ve found it painful (but do-able) to vacu-form and it’s damn near unbreakable. So if a guy like me in his garage with a homebuilt vacu-form can make polycarbonate windows I’m sure you could find a manufacturer that could make a sphere out of it. (polycarbonate was used on SpaceShipOne’s windows). Also, you could reinforce the bubble by wrapping uni-directional carbon fiber in say two inch wide bands leaving big triangular windows to look out.
You make an interesting point with the cheap fuel. Something NASA ignores. At 300mph you’ll reach 62 miles in 12 minutes (less if you’re talking about Indicated Airspeed) in a lightweight vehicle and just burn a lot more fuel, but it’s cheap fuel so who cares! NASA will spend millions to develop rocket motors using the absolute most exotic fuels with the highest impulse to reduce the whole weight of the vehicle by 2% and then spend millions on safe storing and handling of these dangerous fuels (like the hydrazine on that satellite they just shot down).
If you do choose to put an aerodynamic fairing over it’ll be a simple affair. Probably make a cheap fiberglass fairing pretty quickly and it could even be designed to stablize it during re-entry. Just keep in mind that composites expand and contract a LOT between the heat of reentry and cold of 100,000ft.
Good luck, can’t wait to see it fly! I envy the fun you’re team is having making these rockets!
[…] something that is just not that exciting. Armadillo’s suborbital vehicle design, the “six-pack” vehicle, does not even have a pilot on the vehicle: the vehicle is controlled from the ground; the single […]
Given the “no middle ground” of the design, I hope the sphere can separate from the tanks and float down on a parachute. I’d put it on the top of that gerbil ball; is the top where the hatch is?
I know weight is precious, but psychologically it might be hard for tourists to come to grips with “No, there’s no backup system.”
But otherwise that design is inspired. Clearly no other provider can offer a bigger viewport! Absolutely amazing. I’d do it if I had the money.
What about tipping over? Can it really keep upright all the way?