Short trip to 100km

[sugarshot]

I'd like to get your opinions on the things to watch out for when lofting a capsule to 62 miles altitude.

I'm mostly interested in thermal-vacuum management of electronics (staying cool).

Can a drogue be deployed at apogee, and expected to survive a mostly supersonic return trip, without a de-spin operation at apogee? The plan is for a scant few hundred pounds coming back in two sections, going 4 rps on the way up.

Should electronics be in a pressurized cannister, for thermal and other protection reasons? The context is 2 minutes straight(?) up (Mach 5 max.) , and about 8 minutes back, with main parachutes deployed perhaps around 10,000 feet. There will be an 18-watt off-the-shelf transmitter, cameras, sensing, and single board computers, etc, etc..and lithium-ion batteries ?!

Tips and advice about things to watch out for would be greatly appreciated.

thanks

Geoff

 

[InteroperabilityFix]

this is unmanned, right?

for a short trip, I think just sealing the capsule should protect the innards well enough, if you use solid state electronics. I'd recommend your onboard computer to be ruggedized, and self-contained, which will be more expensive than using PC/Laptop components.

rather than a drogue, you should use a disposable ballute deployed at apogee and a parachute pulled out by a drogue at the very end.


_______________________________________
Scientific/Engineering Code Exchange:

http://www.solvengineer.com

 

[sugarshot]

The main body tube is on the order of 22 feet long. We are thinking of seperating the cone at apogee and returning in two pieces.

Presently, we're thinking of free fall until the two sections slow to about 600 mph, then deploy a drogue at that time (sub-sonic deployment).

What comes to mind is we haven't yet evaluated the effect of falling into air at odd angles at rates in the typical mach 4 range, other than being similar to putting each section in a oven for about a half a minute.

I could see a ballute being something easier to implement in the cone section.

 

[GregLocock]

Have you talked to (or are you part of) Ausroc?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[sugarshot]

The project is Sugar Shot to Space, not part of Ausroc.. though one of us is in australia.

 

[btrueblood]

sugarshot,

Have you contacted the people at Reaction Research?

http://www.rrs.org

If you can get ahold of the president, Dave Crisalli, he may be able to point you to several of his club members who have made similar launches, and had similar decisions to make regarding recovery systems. I used to do some work for him on the old XLR-132 project, tell him Ben says hi.