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Post by Joe on Oct 6, 2012 21:01:28 GMT -5
www.latimes.com/business/la-fi-stratospheric-jump-20121004,0,2788286.story Monday ~ dawn. From 23 miles (120K feet). The old record set in 1960 by Joe Kittinger is 103K, or ~ 19 miles-- the edge of space. "[Felix] Baumgartner will be carried skyward inside a pressurized capsule . . . . . . weighing 2,900 pounds — a little more than a Volkswagen beetle — which will be carried by a massive, helium-filled balloon to an altitude of 23 miles near Roswell, N.M. The trip will take up to three hours, and temperatures will fall as low as minus 70 degrees."
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Post by Joe on Oct 9, 2012 16:41:50 GMT -5
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Post by Tom Goodrick on Oct 13, 2012 6:30:05 GMT -5
From what I hear, he's still waiting. That's a tough wait. But I give him only about 30% chance of living. He'll be going pretty fast when he gets enough air to stabilize so he could easily get into a tumble. When he does get air, falling vertically, it will come as a sudden blast that can make him tumble worse. He could lose an arm.
I have advocated that people trying to get home this way ride in a small capsule with attitude-control rockets to keep them straight with some lift/drag so they can come in at an angle avoiding a big crunch.
In practical considerations, you have to wonder how a person gets to that situation anyway. Stepping out from a balloon capsule (which could be the entry capsule) is not very realistic. Anyone escaping from an orbiting device (like a space station) would have a whole new set of problems with excessive energy.
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Post by Joe on Oct 14, 2012 12:37:09 GMT -5
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Post by Joe on Oct 14, 2012 14:04:26 GMT -5
HE DID IT!
Cool sidenote: Joe Kittinger manned CAPCOM.
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Post by Tom Goodrick on Oct 16, 2012 8:15:43 GMT -5
That was a significant accomplishment. He overcame the spin and made a great landing. The inflation of the parafoil canopy was a very significant thing. Hard to say what the chute deployment speed was but it was well above the normal deployment speed.
This feat does not indicate the feasibility of an entry from orbit using just a suit. The energy level that would have to be dissipated is far greater than in this jump. Speed from orbit at initial entry to the atmosphere (close to this same jump altitude) would probably be above Mach 10.
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Post by Joe on Oct 28, 2012 20:48:03 GMT -5
Isn't it possible though to use a suit + chute as a "lifeboat" if one's craft had a problem that made re-entry in it impossible, but slowing to a feasible free-fall speed was still possible? You wouldn't want to jump out of a burning car going 70 mph but you might if it's only going 7 mph.
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Post by Tom Goodrick on Oct 29, 2012 6:24:03 GMT -5
Orbit speed is about 7.2 km/sec. That is at least 100 x more energy than this guy started with. Getting down to his starting energy at his starting altitude would mbe a very big job requiring a lot of deceleration using rocket fuel (a significant retro burn) or entering the atmosphere while still at or near orbit speed and then using drag to decelerate. That would generate a lot of heat that a simple suit could not handle. He would need a capsule with thrust for both attitude control and deceleration. He would need considerable thickness between himself and a special hard composite nose cone, perhaps an ablative nose cone. That gets to be a lot of weight to launch.
I have looked into that for NASA both as a worker and as a consultant and found it quite difficult. The last thing I looked at was the X-38 which was a capsule for getting the crew back from the ISS in cases of injury, illness or malfunction. The people at Houston who worked this directly could not solve the problem. They needed a big parachute. They chose a big gliding parachute so the people could have some additional control of where they land. The project was unsuccessful. Last I heard the capsule weighed just under 30,000 lbs. That's a lot of pounds to launch.
This morning a contractor landed a Space Dragon cargo capsule in the Pacific under round chutes. I heard it went well. It had 8,000 lbs of cargo from the ISS. It's a big ocean. The cargo does not care how long it rides the waves. That is the solution I advocated for the X-38 but I advocated enough on-orbit power to phase the landing, getting toward a desired spot on land with a cushioned landing.
The current Soyuz capsules have inadequate capacity.
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Post by Joe on Nov 3, 2012 2:18:33 GMT -5
What do you think of our space program as it is now, generally speaking (to the extent that the US, even has one anymore)?
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Post by Tom Goodrick on Nov 3, 2012 8:26:57 GMT -5
I am very saddened. The US has allowed a substantial amount of knowledge and expertise to fall into decay. I define "expertise" as the ability to resurrect the knowledge need very readily as when an expert does not need to work a problem from the beginning. He has solved the problem before on paper and he just has to dig through some notes and then he resumes his prior work, perhaps directed more specifically at new program parameters. In 1990, I was assigned to begin work on aerobrakes. I knew nothing about it but everyone assummed that, since I had some expertise in parachutes, I could pick up on aerobrakes. It was a hassle. Parachutes involved mainly aerodynamics and structural analyses of light-weight fabrics. Aerobrakes are fairly heavy, rigid, and involve aerothermodynamics and research in heat dissipation. But I found some local scientists in Huntsville who had worked the problem 20 years earlier for robotic landings on Mars and Venus (that worked fine). I read their papers and we called them in for briefings and conferences.
The Apollo Lunar Return problem is an example of aerobraking although it relied partly on chemical braking. Aerobraking is the process of building a spacecraft to handle entry heat and to manage trajectories so that the orbital energy is dissipated. Weight penalties raise launch costs for both chemical and aerodynamic braking. Studies have to be made as to which is best for a given mission.
I remember walking to the rental car in parking lot with two of these experts noting that I was a "young 49-year-old" while they were in their 60's. We had attended a conference in Washington at which the people at the top had said our aerobrake efforts were too extotic and would probably be cancelled. I had also recently given a paper at an international conference in Montreal on aerobraking where I presented a new empirical relation that was well-received. I remarked to the older guys that I felt I was just beginning to understand the problem they had worked years earlier and now my work as well as theirs would be shut down and would collect dust for another decade. (Try two or three more decades.) Then some other young people would take it up.
After shutting down my aerobrake work, I had time to develop a new general purpose entry trajectory program that could be used for many things, including the study of aerobrakes. But I left rather abruptly 4 years later when I saw most of areas of work being defunded. I have little hope that my program will ever be used. First because it relies on an operators thought and actions during the computation based on what he sees. Modern engineers don't like that. They set up a program and let it run itself until it hands them a solution. Curiously that was the mentality I found at NASA left over from Apollo. Secondly I used compiled Microsoft Basic which has been abandoned by Micosoft. I used it because it let me build complex elements much faster than other languages.
So it goes.
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