That a good idea
A system can be designed to use a streamlined capsule that could hit the water at rather high velocity without jarring the payload. Make it bouyant and you get it back when it floats to the surface. If something goes wrong and it cracks when hitting the water, you would at least know where it is. The payload section would need a lot of reinforcement, but the mass penalty is definitely less than an airbag system.
The question would be can you design a vehile to transition from air to water at 200+ miles per hour with minimum shock?
Joe L.
James McEnanly wrote:
In the early manned space program, all of the capsules landed at sea. How well would a water landing work? --- Michael Turner <[EMAIL PROTECTED]> wrote:
I'm told they might have used the kind of balloons
they used on the recent Martian landings, but that would have greatly increased the weight -- and therefore > the cost -- of what was supposed to be a relatively inexpensive return system. But I bet they're rethinking that now.
Maybe the balloon shock absorber idea could be turned upside down - you could cover the target zone with balloons. Hmm, that would be a large area.
OK, how about this: when you figure out where the sample return capsule is going to land (to within a couple hundred meters), send planes to carpet-bomb that area with bombs that produce huge masses of foam for the capsule to plunge into.
Let's see, if you engineer the capsule to withstand 20 g deceleration, and the capsule comes in at maybe 400 mph terminal velocity, straight down, and the foam can resist at 20 g, that's maybe only 60-70 ft of foam.
Hmm, but that foam is probably styrofoam-stiff. Maybe no foaming process is
fast enough.
Well, then (yes, I *do* have a million half-back ideas, thank you for asking) if the foaming gases are shock-reactive, you might get good deceleration even with a lighter foam. Plus, the whole foam pad self-disposes by combustion before you can say "environmentalist picketers." (Heat stress on the capsule? Yeah, but maybe no worse than what you get already with reentry.)
Call it "scorched-earth splashdown". Kinda crazy, but maybe not as crazy as trying to sift through a gazillion tiny shards of silicon and germanium to find a few that can still tell you something. And if Scorched Earth Splashdown cost $10 million a shot, well, this splat was a $260 million splat. Maybe it's worth experimenting with just as a backup to the James Bond Helicopter Retrieve. (And it would certainly be worthy of a scene from a James Bond movie if it worked.)
OK, I'll go back to playing with matches now.
-michael turner [EMAIL PROTECTED]
[EMAIL PROTECTED] wrote: -----
To: <[EMAIL PROTECTED]> From: "Michael Turner" <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] Date: 09/09/2004 09:04PM Subject: Re: the latest splat
> I was there in the hangar at Dugway Proving Grounds as we watched the > capsule embed itself in the dry lakebed. My girlfriend works on the Genesis > project at JPL and I was along as her guest.
Gee, if I weren't married, I'd try to figure out what cafes to hang out in, around JPL ;-)
> It was a terribly sad moment, as you can imagine, and a long, sad > afternoon. Through my girlfriend, I had met some of the key engineers and > scientists involved. I saw that the project manager was on the verge of > tears as he tried to answer reporters' questions about what had gone wrong. > One scientist had been supporting the idea for 14 years, I believe he said, > and some of the engineers had lived it with three or more years.
One of the unfortunate things about this incident is that it casts a shadow over an the idea really sounds very sensible - it's just that the parachute system wasn't cooperating that day. Reentry survival equipment isn't really "payload" - it's just the last stage of the overall sample delivery system. Why design the craft itself for soft landings when it costs so much to send things into space? If some such soft-landing gear weighs, say, 100 lbs, the cost of retrieving by helicopter instead seems like it would be cost-competitive even for the lower range of launch costs.
> I work in publishing for the IEEE Computer Society. Sometimes, one of the > magazines I help launch doesn't do as we hoped, so over a period of several > months, we get the bad news. That's tough enough, but it must be really > wrenching to see your dreams come crashing down in a matter of seconds.
I got out of software development because I got so sick of the typical 60-80% project failure rate. But at least I got to see some projects go to completion. I can't imagine what it must be like to see a project end up in splinters after a decade or more. It must be a little like watching a home you built burn down.
> (Incidentally, I understand that the Stardust material would withstand the > kind of impact that shattered the silicon and germanium wafers in Genesis > to smithereens. The Stardust material is an almost lighter-than-air foam. I > forget the name, but I got to hold a piece when my 10-year-old daughter and > I went to JPL's open house this summer.)
"Aerogel"?
-michael turner [EMAIL PROTECTED]
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Sincerely
James McEnanly
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