I would like to ask you folks a question

When the shuttles take off and they (Houston) tell the astronauts "go
with throttle up or maxq" is it at that point the most dangerous part of
the launch?

Stephen Lombardo wrote:
When the shuttles take off and they (Houston) tell the astronauts "go
with throttle up or maxq" is it at that point the most dangerous part of
the launch?


i am new to this newsgroup, and i think after the challenger accident, i
have to hold my breath during that time.

Angela

On Sun, 07 Aug 2005 06:54:29 -0400, angela copus wrote:

Stephen Lombardo wrote:
When the shuttles take off and they (Houston) tell the astronauts "go
with throttle up or maxq" is it at that point the most dangerous part of
the launch?


i am new to this newsgroup, and i think after the challenger accident, i
have to hold my breath during that time.

I think the "most dangerous" part of the launch is probably the liftoff itself.
Although I guess it's a very reliable system, my heart always skips a
beat or two between the shuttle engine ignition and that of the SRBs.

But the "Go at throttle up" call... well, yeah. I'm a little bit surprised they
didn't rephrase that one. And a little bit glad they didn't, as well.

Dale

I don't know if that is the MOST dangerous part of the launch. The
shuttle throttles back while it is going through the max. pressure,
and then throttles up after the pressure has decreased.

I beleive the entire launch is dangerous. If memory serves me,
Challenger was cleared for throttle up when it exploded. It's problems
came from an SRB seal. The SRB are not throttled. Once, lit they keep
burning until the fuel is exhusted. Columbia's foam problem did not
begin during the trottle adjustment period.

Typically at:
T +0:38 Main Engine Throttle down (1316mph)
T +0:52 Main Engine Throttle Up (1493mph)


On Sun, 7 Aug 2005 03:30:23 -0700, (Stephen
Lombardo) wrote:

When the shuttles take off and they (Houston) tell the astronauts "go
with throttle up or maxq" is it at that point the most dangerous part of
the launch?

wrote in message
...
I don't know if that is the MOST dangerous part of the launch. The
shuttle throttles back while it is going through the max. pressure,
and then throttles up after the pressure has decreased.

I beleive the entire launch is dangerous. If memory serves me,
Challenger was cleared for throttle up when it exploded.

Couple of corrections.

The call, "Go at throttle up" is an indication that the throttle up has
already successfully occurred.

Also, to be pedantic, Challenger did not explode, but broke up due to
aerodynamic forces on it as a result of the nose pitching up after the ET
broke up.

Yes, it may sound like a quibble, but does gives one a better understanding
of what happened.


Personally I think SRB ignition is the most dangerous part of the launch.
If one fails, it's a "bad day."


It's problems
came from an SRB seal. The SRB are not throttled. Once, lit they keep
burning until the fuel is exhusted. Columbia's foam problem did not
begin during the trottle adjustment period.

Typically at:
T +0:38 Main Engine Throttle down (1316mph)
T +0:52 Main Engine Throttle Up (1493mph)


On Sun, 7 Aug 2005 03:30:23 -0700, (Stephen
Lombardo) wrote:

When the shuttles take off and they (Houston) tell the astronauts "go
with throttle up or maxq" is it at that point the most dangerous part of
the launch?

"Stephen Lombardo" wrote in message
...
When the shuttles take off and they (Houston) tell the astronauts "go
with throttle up or maxq" is it at that point the most dangerous part of
the launch?

This means the shuttle has already passed the point where the aerodymanic
stresses are at the maximum during the launch phase. This is generally
around Mach 1--the transonic region. The stress on the vehicle drops off
dramatically from that point on. On some flights, you can even see a
shockwave form on the vehicle at MaxQ, then disappear.

The Main Engines throttle back to (IIRC) 70-75% of rated power through MaxQ.
Similarly, the solid propellant in the SRB's is shaped to reduce thrust at
the same time. Continuing to pour on power at this point would overstress
the ship and "might" lead to a breakup.

When the shuttles take off and they (Houston) tell the astronauts "go
with throttle up or maxq" is it at that point the most dangerous part of
the launch?

yes that is the point at which the shuttle is most likely to explode and
kill everyone on board