hobrien@pluton.matrox.com (Hugh O'Brien) (04/12/91)
Hi Folks,
Sometime in 1985 I remember seeing a shuttle landing on TV where
there was a clean flame emanating from near the base of the tail
after the orbiter had come to a stop. If my memory serves me correctly,
it was 4 to 6 feet long. It looked exactly like the flame from a
butane lighter.
I was completely freaked out, I was half-expecting the shuttle to
blow-up any second. I cringed when the ignorant (stupid?) announcer
on TV commented on it by saying, "Well look at that, the shuttle got
so hot on reentry that it's on fire." He said this in a jovial way,
not taking it seriously.
Recently I saw another landing where there was a nasty trail of
smoke coming from the same section of the tail. The smoke persisted
for the full five minutes that I watched.
What gives? Did some sort of gas/hydraulic line rupture? How come
nothing like this was ever mentioned in the layman press?
I have been pondering this for years.
Hugh O'Brien
USENET: hobrien@matrox.comwdh@hrshcx.csd.harris.com (W. David Higgins) (04/12/91)
In article <1991Apr11.223534.12896@pandora.matrox.com> hobrien@pluton.matrox.com (Hugh O'Brien) writes:
. Sometime in 1985 I remember seeing a shuttle landing on TV where
. there was a clean flame emanating from near the base of the tail
. after the orbiter had come to a stop.
.
. What gives? Did some sort of gas/hydraulic line rupture? How come
. nothing like this was ever mentioned in the layman press?
.
. I have been pondering this for years.
Jeez, you should have asked. It's the APU exhaust plume. You
probably saw an infrared image from a '85 night landing. The plume is very
evident then. Daytime it is harder to see.
--
-- W. David Higgins (hrshcx!wdh)
-- Harris Computer Systems, Ft. Lauderdale, FL 33309 305-973-5351 jonkatz@gn.ecn.purdue.edu (Jonathan W. Katz) (04/12/91)
In article <1991Apr11.223534.12896@pandora.matrox.com> hobrien@pluton.matrox.com (Hugh O'Brien) writes: > Recently I saw another landing where there was a nasty trail of >smoke coming from the same section of the tail. The smoke persisted >for the full five minutes that I watched. > > What gives? Did some sort of gas/hydraulic line rupture? How come >nothing like this was ever mentioned in the layman press? > I will probably be half correct with this answer. What you saw was gas venting from the APU's. It is completely normal for you to see this. (I'm just not sure that it's the APU's) Jonathan W. Katz Purdue University School of Aeronautical and Astronautical Engineering
jonkatz@gn.ecn.purdue.edu (Jonathan W. Katz) (04/12/91)
In article <1076@hrshcx.csd.harris.com> wdh@hrshcx.csd.harris.com (W. David Higgins) writes: >In article <1991Apr11.223534.12896@pandora.matrox.com> hobrien@pluton.matrox.com (Hugh O'Brien) writes: >. Sometime in 1985 I remember seeing a shuttle landing on TV where >. there was a clean flame emanating from near the base of the tail >. after the orbiter had come to a stop. >. >. What gives? Did some sort of gas/hydraulic line rupture? How come >. nothing like this was ever mentioned in the layman press? >. > Jeez, you should have asked. It's the APU exhaust plume. You >probably saw an infrared image from a '85 night landing. The plume is very >evident then. Daytime it is harder to see. Actually, what he saw back in '85 (?) was an actual fire in the Columbia engine room that did a lot of damage. Jonathan W. Katz Purdue University
ejbehr@rs6000.cmp.ilstu.edu (Eric Behr) (04/12/91)
In infra-red, the Shuttle after landing *does* look like an overworked Soviet tractor (tile heat and APU exhaust, I guess). Since night landings are becoming common, TV coverage includes a lot of IR images. Perhaps that's what you saw. -- Eric Behr, Illinois State University, Mathematics Department Internet: ejbehr@rs6000.cmp.ilstu.edu Bitnet: ebehr@ilstu
kent@vf.jsc.nasa.gov (04/12/91)
In article <1991Apr11.223534.12896@pandora.matrox.com>, hobrien@pluton.matrox.com (Hugh O'Brien) writes: > Sometime in 1985 I remember seeing a shuttle landing on TV where > there was a clean flame emanating from near the base of the tail > after the orbiter had come to a stop. If my memory serves me correctly, > it was 4 to 6 feet long. It looked exactly like the flame from a > butane lighter. > > I was completely freaked out, I was half-expecting the shuttle to > blow-up any second. I cringed when the ignorant (stupid?) announcer > on TV commented on it by saying, "Well look at that, the shuttle got > so hot on reentry that it's on fire." He said this in a jovial way, > not taking it seriously. > > Recently I saw another landing where there was a nasty trail of > smoke coming from the same section of the tail. The smoke persisted > for the full five minutes that I watched. > > What gives? Did some sort of gas/hydraulic line rupture? How come > nothing like this was ever mentioned in the layman press? > > I have been pondering this for years. > What you are seeing is the exhaust gases from the Auxiliary Power Units (APU). The three APU's use Hydrozine for fuel. The APU's drive the Hydraulic pumps on the Orbiter. The Shuttle uses hydraulic power to move the control surfaces during landing and move the main engines during ascent. The APU are kept on for about 5 minutes after landing so the main engines can be repositioned to the "rain drain" position after landing. During reentry, the engines are in the highest position. After landing they moved down. -- Mike Kent - Lockheed Engineering and Sciences Company at NASA JSC 2400 NASA RD One, Houston, TX 77058 (713) 483-3791
kent@vf.jsc.nasa.gov (04/13/91)
In article <1991Apr12.034927.25257@gn.ecn.purdue.edu>, jonkatz@gn.ecn.purdue.edu (Jonathan W. Katz) writes: > > Actually, what he saw back in '85 (?) was an actual fire in the Columbia > engine room that did a lot of damage. > > Jonathan W. Katz > Purdue University This is partially correct. Several APU fuel lines had broken causing a small fire in the aft bulkhead. The fire was not in the engine room. As a result of the fire the APU fuel lines were replaced with stronger ones. -- Mike Kent - Lockheed Engineering and Sciences Company at NASA JSC 2400 NASA RD One, Houston, TX 77058 (713) 483-3791
karn@epic.bellcore.com (Phil R. Karn) (04/13/91)
In article <1991Apr12.034927.25257@gn.ecn.purdue.edu>, jonkatz@gn.ecn.purdue.edu (Jonathan W. Katz) writes: |> >. Sometime in 1985 I remember seeing a shuttle landing on TV where |> >. there was a clean flame emanating from near the base of the tail |> >. after the orbiter had come to a stop. |> Actually, what he saw back in '85 (?) was an actual fire in the Columbia |> engine room that did a lot of damage. You're referring to STS-9 (late 1983), and although there was indeed a fire inside an engine bay AND an externally visible plume, these were completely independent phenomena. The (accidental) fire was NOT visible - the external plume was just the APU exhaust, as mentioned by others here. The APUs run on catalytically decomposed hydrazine (N2H4). When you decompose hydrazine, you get hot nitrogen and hydrogen. Hydrogen is flammable, so it can burn if oxygen is present. This is normal, expected and safe. Phil
digex@world.std.com (doug e humphrey) (04/13/91)
Another possibility would be them burning off Hydrazine, which is used for the various small positioning thrusters. Does anyone know for sure what they do with the leftover Hydrazine in the shuttle after landing? It is nasty stuff; we used to use it in sounding rockets, and the Hydrazine test range had a telephone pole that was visible from the main gates about half a mile away, with green, amber and red lights on top. If green was lit, you were OK to drive the half mile in to the test trailers; if amber, stop and wait, since something dangerous was happening, and if red, get to the nearest phone and call GSFC security to say "Oh hell..." Doug Humphrey Digital Express Group Crypto Systems Division (this week...)
cjp310@coombs.anu.edu.au (Chris @ SSDA ...) (04/13/91)
kent@vf.jsc.nasa.gov writes: >In article <1991Apr12.034927.25257@gn.ecn.purdue.edu>, jonkatz@gn.ecn.purdue.edu (Jonathan W. Katz) writes: >> etc... >This is partially correct. Several APU fuel lines had broken causing a >small fire in the aft bulkhead. The fire was not in the engine room. >As a result of the fire the APU fuel lines were replaced with stronger ones. >-- >Mike Kent - Lockheed Engineering and Sciences Company at NASA JSC > 2400 NASA RD One, Houston, TX 77058 (713) 483-3791 Sorry for my ignorance but what is an APU ?? thanks Chris -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Chris Patterson | Ph: +61 6 2492185 Social Science Data Archives | AARNet: Chris@coombs.anu.edu.oz Australian National University | "I wonder what happens if I ..."