Cold-gas propulsion test

[dlavery]

The Common Modular Spacecraft Bus (CMSB) is a spacecraft concept being developed by the NASA Ames Research Center in Mountain View, CA. The CMSB is being designed to be compatible with lunar surface, Mars orbit, asteroid surface, and Earth orbit missions. The system is relatively unique, because it uses a cold gas propulsion system rather than a hot combustion rocket. This only allows a few seconds of flight in Earth gravity, but that is sufficient to demonstrate the principles of the propulsion system. It also drastically reduces the time required to recover, refuel and prepare the CMSB for repeated flights. Traditional rockets may require weeks or months to refurbish and refly, while the CMSB testbed can be reflown within an hour. This video shows some of the CMSB hover flight tests from late 2007 and early 2008. I thought some of you might be interested.

-dave

(I also must commend the flight team on their choice of wardrobe, as can be observed in the second scene. )

[EricH]

Originally Posted by dlavery

(I also must commend the flight team on their choice of wardrobe, as can be observed in the second scene. )

I think that guy looked like one Dave Lavery from the back... Any comment on that?

Seriously, though, it looks really cool. (And doesn't sound really loud like a standard hot-gas rocket.) Question is, how does it work for BIGGER things?

[tseres]

thats really cool dave!

PS
could this possibly be an idea for legal robot parts next year?

[seanwitte]

There is an article about this on Wired:

http://blog.wired.com/wiredscience/2...-meet-the.html

[Kevin Sevcik]

Correct me if I'm wrong, but from the Wired article it sounds like they're using the cold gas propulsion on the test bed as a cheap fuel source that allows for a turnaround time of less than an hour specifically so they can cheaply run a lot of tests on the navigation and control system without worrying about pesky things like fire, crashes, and exploding million dollar test engines. It's certainly a great idea and should help prevent some future embarrassments, but I can't really see how you can get the specific impulse high enough to make it feasible for a main engine for an actual mission. Especially since it sounds like the missions the CMSB is meant for are going to be one-way trips where turnaround time is unimportant, since it won't be. So kudos for saving money and time in development, but I'm still wondering if cold gas is going to be the propellant for the craft in service.

[seanwitte]

I've been watching Armadillo (http://www.armadilloaerospace.com) for a few years. They have pretty short turn-around between tests, but the engines are very loud and hot. They never seemed to have as much trouble with the software but have invested a lot of effort in the engines. I don't know how much data you can collect from a 6 second flight, but the ability to do it 9 or 10 times a day is attractive. Combine that frequency with a safe propellant that's basically free. Maybe NASA can buy one of Carmack's vehicles when they're ready for a live test.