jakee 1,490 #51 June 13, 2006 It seems our very own Billvon has done some thinking in this area as well. Here is a little short fiction of his about wreckage riding from a space station.Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
jumper03 0 #52 June 13, 2006 well, make the problem simpler to start off with first. Assume the Earth does not rotate and you can jump off of a 400 km high tower. If you can survive that then add in rotation. Basically pilot dave hit the nail on the head. From 400 km until you hit significant atmosphere (somewhere around 50 km) you'll be accelerating at 9.8 m/s every second. Meaning you'll be doing about 267 m/s when you reach that thicker atmosphere. That's pretty fucking fast... To slow down to a terminal velocity we are used to - around 50 m/s - you'll have to bleed off that speed - it will be done via friction - friction will generate heat - take some marshmellows with you.Scars remind us that the past is real Quote Share this post Link to post Share on other sites
Slappie 9 #53 June 13, 2006 Quotewell, make the problem simpler to start off with first. Assume the Earth does not rotate and you can jump off of a 400 km high tower. If you can survive that then add in rotation. Basically pilot dave hit the nail on the head. From 400 km until you hit significant atmosphere (somewhere around 50 km) you'll be accelerating at 9.8 m/s every second. Meaning you'll be doing about 267 m/s when you reach that thicker atmosphere. That's pretty fucking fast... To slow down to a terminal velocity we are used to - around 50 m/s - you'll have to bleed off that speed - it will be done via friction - friction will generate heat - take some marshmellows with you. Just what I said!! See my piloting skills are coming to good use. "Find out just what any people will quietly submit to and you have found out the exact measure of injustice and wrong which will be imposed upon them." Quote Share this post Link to post Share on other sites
twibbles 0 #54 June 13, 2006 Quotewell, make the problem simpler to start off with first. Assume the Earth does not rotate and you can jump off of a 400 km high tower. If you can survive that then add in rotation. Basically pilot dave hit the nail on the head. From 400 km until you hit significant atmosphere (somewhere around 50 km) you'll be accelerating at 9.8 m/s every second. Meaning you'll be doing about 267 m/s when you reach that thicker atmosphere. That's pretty fucking fast... To slow down to a terminal velocity we are used to - around 50 m/s - you'll have to bleed off that speed - it will be done via friction - friction will generate heat - take some marshmellows with you. Say, from 50km, to 1km, roughly opening height, we got 49km to play aound with. Do you think it's possible to spreas the deeceleration evenly across 49km? And if so, just got to figure out if the heat generated is survivable, an the maximum deeceleration is surviavble too. Now, just got to find the drag coefficient of the object in question, and figure out how much heat is generated. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move." Quote Share this post Link to post Share on other sites
normiss 801 #55 June 13, 2006 That's kickass BillVon! Where's the rest of the story??? Quote Share this post Link to post Share on other sites MF42 0 #56 June 13, 2006 I've heard that during the development of the SR-71 on at least one occasion the plane broke up at very high altitudes while doing better than mach3, and the crew survived in their ejection seats. Instead of dropping off the space station, why not ride on a Spaceship One type craft just barely outside the atmosphere, then bail out. I'm envisioning a slowly ablative canopy that would be huge to slow your descent through the upper atmosphere, but burn/shrink away the lower you go, so you're gradually slowed to a normal terminal velocity once the thicker lower atmosphere is reached. Sure it would need some truly exotic materials technology, but I don't see why it couldn't be done. Somebody call Rutan and get him working on this ASAP! Matt Quote Share this post Link to post Share on other sites jumper03 0 #57 June 13, 2006 QuoteQuotewell, make the problem simpler to start off with first. Assume the Earth does not rotate and you can jump off of a 400 km high tower. If you can survive that then add in rotation. Basically pilot dave hit the nail on the head. From 400 km until you hit significant atmosphere (somewhere around 50 km) you'll be accelerating at 9.8 m/s every second. Meaning you'll be doing about 267 m/s when you reach that thicker atmosphere. That's pretty fucking fast... To slow down to a terminal velocity we are used to - around 50 m/s - you'll have to bleed off that speed - it will be done via friction - friction will generate heat - take some marshmellows with you. Say, from 50km, to 1km, roughly opening height, we got 49km to play aound with. Do you think it's possible to spreas the deeceleration evenly across 49km? And if so, just got to figure out if the heat generated is survivable, an the maximum deeceleration is surviavble too. Now, just got to find the drag coefficient of the object in question, and figure out how much heat is generated. Eugene to find out how much heat - just use the difference between the kinetic energy. So at 267 m/s a skydiver whose total mass is 100 kg will have 3.6 x 10^6 Joules of energy; at 50 m/s the skydiver will have 1.3 x 10^5 Joules of energy. That's a difference of over a million joules.... consider that a baseball at 50 m/s has 250 joules of energy - ever been hit by a baseball? That's alot of energy. On second thought - take two bags of marshmallowsScars remind us that the past is real Quote Share this post Link to post Share on other sites soberamprat 0 #58 June 13, 2006 I am thinking that a geosynchronous orbit would take care of the orbital velocity. But at just 130,000ft you reach about 1000 mph before you start to slow down, so I am thinking that you would reach temps a lot more then the Concord did at 14000 mph and its nose cone got to about 260 meaning you probably get hotter then that which means you would be well done and ready to eat. http://www.swoopstudios.com/videos/videos-rex.php Quote Share this post Link to post Share on other sites twibbles 0 #59 June 13, 2006 Just thought about it, i wonder what the heat load is on SpaceShipOne? It's flying pretty much the same profile that the post is about, the re-retry is anyway. It goes straight up, up to 100Km, the FAI definaton of the edge of space, then back down again. Not much in the way of heat shield on SpaceShipOne as well, but it still gets quite hot i guess. Also, i reckon a part of the heat generated by the re-entering skydiver would be absorbed(?) by the air around him/her. But forget marshmellows, i'm bringing a pre-marinated chicken to roast, and some potato in foil in the pockets... Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move." Quote Share this post Link to post Share on other sites CDRINF 1 #60 June 13, 2006 Check it out. These were serious concepts in the 60's: http://www.astronautix.com/craftfam/rescue.htm I like the MOOSE system the best. CDR Quote Share this post Link to post Share on other sites MarkM 0 #61 June 14, 2006 Quote To slow down to a terminal velocity we are used to - around 50 m/s - you'll have to bleed off that speed - it will be done via friction - friction will generate heat - take some marshmellows with you. This isn't done via friction, but ram pressure. When you enter the atmosphere at high speeds you create a shockwave and compress the air in front of it which heats up. The force rides the shock layer a very short distance from the object and heats it up without actually contacting it. But if you're in orbit, you're travelling really really fast to keep the 80% of Earth's gravity that's still there from pulling you back down. So any skydiver suit would have to handle 1500-3000F for a solid 10 mins of reentry. Now if you go from 0 speed from suborbit and only reach mach 3 like Spaceship One did, you'd only have to deal with 1000F. That's probably a much better place to start from Quote Share this post Link to post Share on other sites Prev 1 2 3 Next Page 3 of 3 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. 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MF42 0 #56 June 13, 2006 I've heard that during the development of the SR-71 on at least one occasion the plane broke up at very high altitudes while doing better than mach3, and the crew survived in their ejection seats. Instead of dropping off the space station, why not ride on a Spaceship One type craft just barely outside the atmosphere, then bail out. I'm envisioning a slowly ablative canopy that would be huge to slow your descent through the upper atmosphere, but burn/shrink away the lower you go, so you're gradually slowed to a normal terminal velocity once the thicker lower atmosphere is reached. Sure it would need some truly exotic materials technology, but I don't see why it couldn't be done. Somebody call Rutan and get him working on this ASAP! Matt Quote Share this post Link to post Share on other sites
jumper03 0 #57 June 13, 2006 QuoteQuotewell, make the problem simpler to start off with first. Assume the Earth does not rotate and you can jump off of a 400 km high tower. If you can survive that then add in rotation. Basically pilot dave hit the nail on the head. From 400 km until you hit significant atmosphere (somewhere around 50 km) you'll be accelerating at 9.8 m/s every second. Meaning you'll be doing about 267 m/s when you reach that thicker atmosphere. That's pretty fucking fast... To slow down to a terminal velocity we are used to - around 50 m/s - you'll have to bleed off that speed - it will be done via friction - friction will generate heat - take some marshmellows with you. Say, from 50km, to 1km, roughly opening height, we got 49km to play aound with. Do you think it's possible to spreas the deeceleration evenly across 49km? And if so, just got to figure out if the heat generated is survivable, an the maximum deeceleration is surviavble too. Now, just got to find the drag coefficient of the object in question, and figure out how much heat is generated. Eugene to find out how much heat - just use the difference between the kinetic energy. So at 267 m/s a skydiver whose total mass is 100 kg will have 3.6 x 10^6 Joules of energy; at 50 m/s the skydiver will have 1.3 x 10^5 Joules of energy. That's a difference of over a million joules.... consider that a baseball at 50 m/s has 250 joules of energy - ever been hit by a baseball? That's alot of energy. On second thought - take two bags of marshmallowsScars remind us that the past is real Quote Share this post Link to post Share on other sites
soberamprat 0 #58 June 13, 2006 I am thinking that a geosynchronous orbit would take care of the orbital velocity. But at just 130,000ft you reach about 1000 mph before you start to slow down, so I am thinking that you would reach temps a lot more then the Concord did at 14000 mph and its nose cone got to about 260 meaning you probably get hotter then that which means you would be well done and ready to eat. http://www.swoopstudios.com/videos/videos-rex.php Quote Share this post Link to post Share on other sites
twibbles 0 #59 June 13, 2006 Just thought about it, i wonder what the heat load is on SpaceShipOne? It's flying pretty much the same profile that the post is about, the re-retry is anyway. It goes straight up, up to 100Km, the FAI definaton of the edge of space, then back down again. Not much in the way of heat shield on SpaceShipOne as well, but it still gets quite hot i guess. Also, i reckon a part of the heat generated by the re-entering skydiver would be absorbed(?) by the air around him/her. But forget marshmellows, i'm bringing a pre-marinated chicken to roast, and some potato in foil in the pockets... Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move." Quote Share this post Link to post Share on other sites
CDRINF 1 #60 June 13, 2006 Check it out. These were serious concepts in the 60's: http://www.astronautix.com/craftfam/rescue.htm I like the MOOSE system the best. CDR Quote Share this post Link to post Share on other sites
MarkM 0 #61 June 14, 2006 Quote To slow down to a terminal velocity we are used to - around 50 m/s - you'll have to bleed off that speed - it will be done via friction - friction will generate heat - take some marshmellows with you. This isn't done via friction, but ram pressure. When you enter the atmosphere at high speeds you create a shockwave and compress the air in front of it which heats up. The force rides the shock layer a very short distance from the object and heats it up without actually contacting it. But if you're in orbit, you're travelling really really fast to keep the 80% of Earth's gravity that's still there from pulling you back down. So any skydiver suit would have to handle 1500-3000F for a solid 10 mins of reentry. Now if you go from 0 speed from suborbit and only reach mach 3 like Spaceship One did, you'd only have to deal with 1000F. That's probably a much better place to start from Quote Share this post Link to post Share on other sites
