andy@syma.sussex.ac.uk (Andy Clews) (05/22/89)
In an article about the adapted Boeing 747 shuttle-transfer aircraft in the June '89 issue of Spaceflight News, I read that there are a number of constraints governing the ferry-flights. One of these constraints is that the flights cannot take place when there is danger of rain because this apparently is bad for the thermal-protection tiles on the orbiter. If this is so, what happens to the tiles if the orbiter is sitting on the launch pad and there's a rainstorm? How does rain affect the tiles? Or is it because flying through rain at high velocity (up to 250mph in the case of the STA) would act like a high-pressure hose on the tiles and damage them? Surely 250mph rain can't be as bad as 17000mph air which the orbiter meets on re-entry? -- Andy Clews, Computing Service, Univ. of Sussex, Brighton BN1 9QN, ENGLAND JANET: andy@syma.sussex.ac.uk BITNET: andy%syma.sussex.ac.uk@uk.ac Voice: +44 273 606755 ext.2129
henry@utzoo.uucp (Henry Spencer) (05/24/89)
In article <1015@syma.sussex.ac.uk> andy@syma.sussex.ac.uk (Andy Clews) writes: >... Surely 250mph rain can't be as bad as 17000mph air >which the orbiter meets on re-entry? The 250mph rain is not as hot but is much denser. Yes, it's worse. -- Van Allen, adj: pertaining to | Henry Spencer at U of Toronto Zoology deadly hazards to spaceflight. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
exiphm@eutrc3.UUCP (h.munk) (05/24/89)
I remember reading about the shuttle tiles being affected by raindrops
and even fog droplets. It's somewhere in the report on the Challenger
accident. It was stated there that drops could strip the ntiles from
the orbiter, not only on reentry, but also during abort, return to launch site.
If you're interested, I'll look it up (I don't have a copy of the report
in my office)
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Harm Munk | My boss doesn't know what I'm doing
Institute ITP | I don't know what my boss is doing
-TUE/TNO | We're both happy this way
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In article <1015@syma.sussex.ac.uk> andy@syma.sussex.ac.uk (Andy Clews) writes: >In an article about the adapted Boeing 747 shuttle-transfer aircraft in >the June '89 issue of Spaceflight News, I read that there are a number >of constraints governing the ferry-flights. One of these constraints is >that the flights cannot take place when there is danger of rain because >this apparently is bad for the thermal-protection tiles on the orbiter. >If this is so, what happens to the tiles if the orbiter is sitting on >the launch pad and there's a rainstorm? How does rain affect the tiles? >Or is it because flying through rain at high velocity (up to 250mph in >the case of the STA) would act like a high-pressure hose on the tiles >and damage them? Surely 250mph rain can't be as bad as 17000mph air >which the orbiter meets on re-entry? The tiles are coated before launch. I'm not sure what they use now, but it used to be plain old 3M brand Scotchguard! (No smiley, I read it in Av Leak so it MUST be true. They had pictures 'n everything.) Anyhow, the coating burns off during reentry. They don't spray the tiles again before return to Florida because 1) it's time consuming, and 2) it would get in the way of tile refurbishment. I don't know what happens to the tiles if they get wet. -- Gord "water proof is ok, but I'd rather have 100 proof" Deinstadt gd@geovision
exiphm@eutrc3.UUCP (h.munk) (05/26/89)
In article <685@eutrc3.UUCP>, exiphm@eutrc3.UUCP (h.munk) writes: > > I remember reading about the shuttle tiles being affected by raindrops > and even fog droplets. It's somewhere in the report on the Challenger > accident. It was stated there that drops could strip the ntiles from > the orbiter, not only on reentry, but also during abort, return to launch site. > > If you're interested, I'll look it up (I don't have a copy of the report > in my office) > I found the section on weather affecting the Orbiter tiles. It's on pages 186 and 190 of the report of the presidential commission on the Space Shuttle Challenger accident. For those of you who haven't got a copy (yet), I have copied the passage: "... The program also allows consideration of launching with a light rain shower over the Kennedy runway. Although engineering assesments indicate that the tile damage that would result would not affect Shuttle controllability, it would be a serious setback to the program in terms of budget and schedule. ..." On page 190: "... Returning the orbiter also imposes an additional handling risk to the vehicle in both the loading operation and the ferry flight itself. Encountering light precipitation during the ferry flight has caused substantial damage to the Orbiter thermal protection system. These costs and risks, however, are minimal when compared with those of a Space Shuttle mission. ..." *X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X * Harm Munk * My boss still doesn't know that * X Institute ITP-TUE/TNO X I'm doing this, and I still don't X * Eindhoven * know if he wants me doing this. * X The Netherlands X X *X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X*X