PDA

View Full Version : foam problem



mjtibbs
2005-Jul-31, 01:44 AM
Hi,

Im pretty much a space newbie, but the question popped into my head the other day and none of my friends can really answer it.

So the foam broke off the shuttle discovery shortly after the launch (im assuming before it completly left the earth)

if this is the case, how come I havn't heard of any potential "danger" to the spacecraft on leaving the earths atmosphere, and only of the potential risk on the craft's re-entry to earth.

is this because theres only the friction/intense heat when an object enters earth from space, and not the other way round (ie is there no intense heat/friction when the craft LEAVES earth)

I just have the question because i've not heard anything about possible damage after the foam fell off before it left earth.

hope you know what i'm trying to ask.

thanks

--Mike

piersdad
2005-Jul-31, 09:25 AM
the shuttle is nearly above the atmosphere by the time it is doing twice the speed of sound but then it still keeps accelerating to 22 000 km ph ( approx) and when it returns it has to hit the air at this speed and the air is getting denser all the time at this immense speed.
going out is like leaping off a brick wall and rocketing away.
coming back is like giving yourself a little shove and slamming into the brick wall

aeolus
2005-Jul-31, 06:28 PM
Also, the foam falling off isn't the direct problem. When the foam falls off the external tank, some of it hits the belly of the Shuttle, damaging the tiles in the process. This is the real danger (having the thermal tiles on the Shuttle's underside damaged).

mjtibbs
2005-Aug-01, 01:28 PM
ahh ok,

thanks for the info i understand now.

i'm watching the 2nd space walk live right now.... its pretty amazing.

nasa control must have one hell of a transimitter to get the voice communication signals to reach the ISS up there lol!

Darrrius
2005-Aug-01, 01:39 PM
Originally posted by mjtibbs@Jul 31 2005, 01:44 AM
Hi,

Im pretty much a space newbie, but the question popped into my head the other day and none of my friends can really answer it.

So the foam broke off the shuttle discovery shortly after the launch (im assuming before it completly left the earth)

if this is the case, how come I havn't heard of any potential "danger" to the spacecraft on leaving the earths atmosphere, and only of the potential risk on the craft's re-entry to earth.

is this because theres only the friction/intense heat when an object enters earth from space, and not the other way round (ie is there no intense heat/friction when the craft LEAVES earth)

I just have the question because i've not heard anything about possible damage after the foam fell off before it left earth.

hope you know what i'm trying to ask.

thanks

--Mike
The foam broke off the external fuel tank, not Discovery itself. It was a similar incident that caused Colombia to break up on re-entry. A suitcase-sized piece of foam fell away from the External Fuel tank during its launch, punching a hole through heatshield panels in the left wing. The damage did not present problems in orbit, but as the vehicle tried to re-enter Earth's atmosphere, super-heated gases entered the wing and tore the ship apart.