Newsgroups: sci.space.shuttle Path: utzoo!henry From: henry@utzoo.uucp (Henry Spencer) Subject: Re: Radiation danger in high-latitude orbits Message-ID: <1989Aug10.155342.16600@utzoo.uucp> Organization: U of Toronto Zoology References: <3929@ncar.ucar.edu> Date: Thu, 10 Aug 89 15:53:42 GMT In article <3929@ncar.ucar.edu> gary@cgdra.ucar.edu (Gary Strand) writes: > How much radiation does the shuttle receive in a high-latitude (as in > the current 'top secret' mission, supposedly) orbit compared to a > lower-latitude orbit? It's not very significant at the latitudes the shuttle reaches in a launch from KSC (which cannot launch to extreme latitudes for range-safety reasons), unless it gets far enough south to enter the South Atlantic Anomaly. I don't remember the latitudes of the SAA offhand, so I can't be sure of that. The SAA is an area where the inner Van Allen belt is unusually close to Earth, due to asymmetry in the Earth's magnetic field. It's the reason why Skylab had a heavy shielded film safe. But even the SAA isn't really a significant issue unless you're going to be up for months, as I recall. Certainly for Skylab they were worried about fogging sensitive film but not very concerned about the astronauts' exposure. > Also, what's the maximum permissible radiation dosage an astronaut may > receive? There actually is a dose limit for US astronauts, which I'm trying to recall; I think it's the dose that gives 10% higher chances of certain types of cancer, plus a two-year non-specific reduction in average lifespan. I don't think any of the US astronauts has ever come close to hitting the limit. > Did the Soviets give their cosmonauts any extra protection on > their ~year-long Mir flights? It's seriously hard to provide much in the way of shielding with the current cost of getting things into orbit. I doubt that the Soviets did anything; I haven't heard of anything. -- V7 /bin/mail source: 554 lines.| Henry Spencer at U of Toronto Zoology 1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu