Monday, September 21, 2009

A.R.C.A. rockoon project

Based on a post at The Rocketry Blog, I found out about a project (really a series of rockets based on the same fascinating, very novel design) for a many staged rockoon. This large rocket, to be launched from an even larger balloon (rock-oon), is supposed to eventually send a rover to the moon to claim the Google X-prize moon landing reward: $30 million to soft land on the moon and rove a few hundred meters (500). If you click on the post, you will see my shocked reaction to a project that is right up my alley. This project has rockoons, high mass fractions, and a unique design. New ideas are really nice to see.

For the detailed information, please ignore my post and consult the PDF document directly: 20 page PDF on Haas

This video is an overview of the flight plan. I won't lie, I don't really get what the lunar landing may be, or what kind of delta V it would take to soft land directly on the moon. I suppose it depends on the flight time to get there:

Next, these are two overview images of the rocket:

Here is some information about the rocket as designed:

HAAS technical data
Type: Air launched orbital rocket
Stages: 3 (H1+H2+H3)
Rocket vehicle length (with ELE payload): ~18 m
Rocket vehicle diameter: ~4 m
Rocket vehicle gross weight: 23 300 kg
LEO mass: 400 kg

Stage H1
Type: Rocket powered, pressure feed
Used for: Rocket acceleration
Gross weight: 14 800 kg
Burn time: 100 s
Fuel: Hydrogen peroxide 85% + bitumen based fuel
Thrust: 47 600 kgf

Stage H2
Type: Rocket powered, pressure feed
Used for: Rocket acceleration
Gross weight: 7 350 kg
Burn time: 110 s
Fuel: Hydrogen peroxide 85% + bitumen based fuel
Thrust: 24 800 kgf

Stage H3
Type: Rocket powered, pressure feed
Used for: LEO injection
Gross weight: 2 100 kg
Burn time: 168 s
Fuel: Hydrogen peroxide 85% + bitumen based fuel
Thrust: 5 850 kgf

And the balloon:
CARRIER BALLOON technical data
Type: "0" pressure Solar Montgolfier balloon
Used for: rocket launcher lifting to altitude
Balloon diameter: 160 m
Gross weight: 7 000 kg
Volume: 2 000 000 m3 (*Really big!*)
Max. flight altitude: 18 000 m

Here are some additional images of the rocket that I find most impressive. Obviously this is not a flight ready rocket, but even as a model, any real rocketry fan can't help see the potential of thin, lightweight spherical tanks, high altitude bell nozzles, and thinking outside of the box (or cylinder.)

Conclusion and commentary:

Obviously my love of rockoon projects has been made clear. ( Farside 1 Farside 2 ) I particularly enjoy the fact that these rocket stages are very simple, cheap, and reliable.

There are, however, some major concerns. The low ISP of H2O2 is well known. Can a hydrogen peroxide rocket even make orbit? Can it overcome the low ISP? How about cold soaking in space? How about heat in space? Does it need to be vented? What amount of insulation is called for on the upper stages? These are just a few questions that I have.

Having said this, they claim an ISP of 245 sec. for the first stage. If realistic, this is a pretty darn good number. I intially thought that they planned to use the H2O2 as a monopropellant, with a catalyst. This excited me, but also raised the very real question of low ISP. I think the ISP of hydrogen peroxide as a mono prop is, at best, similar to solids. And perhaps often quite lower. However the density of hydrogen peroxide is better than I had expected, at around 1.4 pure. This is really good, far better than hydrogen and even a touch better than liquid oxygen!

By way of advice, I would propose that at least the lowest stage use solid rocket fuel. Perhaps they should even consider, and I know this goes against everything they want because ARCA states that they desire an environmentally sound propellant (and solids are actually among the worst polluters in the rocket world), but perhaps they should consider making all of the stages burn solid fuels. When you go for high mass fraction, you may want to go all out. However, this could change the chamber and tank requirements because of increased insulation and nozzle ablatives. Solids are pretty darn cheap, and very simple. The most advanced solid rocket motors look quite a bit like the stages of this rocket. That is a good sign for these guys - they are taking advantage of the sphere for maximum performance. If only they could get a thin layer of aerogel in there to allow for cryogenics without heavy insulation... but that would greatly increase the costs of the project, and the complexity.

In any event, this is one project to keep your eye on.

ARCA Space ( Aeronautics and Cosmonautics Romanian Association)

1 comment:

M461 said...

they did their first step towards the goal: