Timeline for Does "What happens beyond Kármán, stay beyond Kármán"?
Current License: CC BY-SA 3.0
14 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 17, 2019 at 23:40 | vote | accept | uhoh | ||
| May 17, 2019 at 16:16 | answer | added | Bob Jacobsen | timeline score: 2 | |
| Mar 29, 2019 at 10:08 | vote | accept | uhoh | ||
| May 17, 2019 at 23:40 | |||||
| Feb 25, 2019 at 9:00 | history | tweeted | twitter.com/StackSpaceExp/status/1099957279699415040 | ||
| Feb 25, 2019 at 5:02 | answer | added | uhoh | timeline score: 1 | |
| Jan 5, 2018 at 15:02 | answer | added | PearsonArtPhoto♦ | timeline score: 3 | |
| Jan 5, 2018 at 12:20 | answer | added | Elijah Seed Arita | timeline score: -2 | |
| Jan 4, 2018 at 16:05 | comment | added | Russell Borogove | @Hobbes The expansion cools the exhaust gas mightily; SSME has a chamber temperature of ~3400K and an exhaust temperature of only ~685K (~412C) (according to some random dude on the internet who sounded plausible to me). | |
| Jan 4, 2018 at 10:07 | comment | added | uhoh | @Hobbes however expansion $\rightarrow$ cooling, until the point where the density is so low that there are no further collisions, at which point the endpoint temperature will be "remembered" by the distribution of final velocities of the individual molecules with respect to the average CM exhaust velocity. There will be a ~4k m/s component behind the nozzle with a ~1k m/s transverse component, but the characteristic $k_B T$ of the exponential tail will reflect the temperature of the "cooled-off" gas after expansion. | |
| Jan 4, 2018 at 9:38 | comment | added | Hobbes | Rocket exhaust has a high temperature, so some molecules will be at escape velocity. | |
| Jan 4, 2018 at 3:40 | comment | added | jwzumwalt | At 100,000 ft (19mi) the earths atmosphere is 1%. Even at 250mi the Space Station still encounters enough air molecules that it must be re-thrusted every few weeks. So, it seems reasonable that unless there is some unknown consequence such as was found with CFE's on the ozone layer, 100k and above would have little impact. Near Space is considered to start at approximately 65,000ft (12mi). en.wikipedia.org/wiki/Mesosphere | |
| Jan 4, 2018 at 2:10 | comment | added | Russell Borogove | Depends on which way you're thrusting. Rocket exhaust goes backward relative to the rocket at ~3000-4500 m/s; for typical LEO/GEO insertions, that leaves the exhaust in an Earth-suborbital trajectory, so you should expect the bulk of it to reenter. Even Apollo's translunar injection adds ~3200 m/s to LEO velocity using an exhaust velocity of ~4100 m/s! Obviously unless you have an infinitely long nozzle (= absolute zero exhaust temperature) there will still be some loss from plume dispersion, though. | |
| Jan 4, 2018 at 1:35 | comment | added | Organic Marble | Related: thelastmanonearth.blogspot.com/2008/06/… | |
| Jan 4, 2018 at 1:18 | history | asked | uhoh | CC BY-SA 3.0 |