[amsat-bb] Re: Since We Are Off Topic Somewhat....

[Ransom, Kenneth G. (JSC-OC)[BAR]]

Found some generic info that might shed some insight as to how fast the
shuttle gets into the thin air and at what speed. 

The following is an excerpt from
http://www.globalsecurity.org/space/library/report/1988/stsover-launch.h
tml#stsover-flight

It reaches the point of maximum dynamic pressure (max Q) -- when dynamic
pressures on the Shuttle are greatest -- about 1 minute after liftoff,
at an altitude of 33,600 ft. 

Little more than 2 minutes into the flight, the SRBs, their fuel
expended, are jettisoned from the orbiter. The Shuttle is at an altitude
of about 30 miles and traveling at a speed of 2,890 miles an hour. 

At about 8 minutes into the flight, at an altitude of about 60 miles,
main engine cut-off (MECO) occurs. The Shuttle is now traveling at a
speed of 16,697 mph.


Kenneth - N5VHO

-----Original Message-----
From: Joe [mailto:nss at mwt.net] 
Sent: Thursday, February 14, 2008 8:18 PM
To: Ransom, Kenneth G. (JSC-OC)[BAR]
Cc: AMSAT-BB
Subject: Re: [amsat-bb] Re: Since We Are Off Topic Somewhat....

Does anyone have the actual speeds at each altitude going up vs coming
down?

I tried to find such a graph, chart, table etc, to no avail,

Joe

Ransom, Kenneth G. (JSC-OC)[BAR] wrote:

>The amount of time spent in the atmosphere at high velocity (I'd have
to do some digging to give some real time data but basically it is as
follows).
> 
>One the way up, the rocket goes through the 100 km of air during the
slower part of the change of velocity and spends very little time in the
atmosphere at the higher velocity.
> 
>On the way down, the object starts to encounter the atmosphere at
maximum velocity and therefore maximum friction. It will be in the
atmosphere for the a much longer period since it comes in a very shallow
angle. The object will have that friction nearly the entire trip to the
ground even though the drag from the atmosphere will slow the object. 
> 
>Kenneth - N5VHO
>
>________________________________
>
>From: amsat-bb-bounces at amsat.org on behalf of Joe
>Sent: Thu 2/14/2008 5:55 PM
>To: 'AMSAT-BB'
>Subject: [amsat-bb] Since We Are Off Topic Somewhat....
>
>
>
>Hi All,,
>
>Since we are somewhat off topic for the moment with the conversation
>about the bird to come down shortly..
>Ok,  the question is,  and i've asked it to several other places, and
>yet to even get a answer,
>
>The question is,,,
>
>Space shuttle launches,,  starts off at sea level,  and in less than
ten
>minutes goes from  zero to 17K MPh (or so)  And gets to orbital
altitude.
>
>Time to come down,, the de-orbit burn happens to slow it down just a
bit
>to cause the orbit to more or less decay.. It's at orbital altitude..
>and moving at about 17K MPh..  45 minutes or so later it's back on the
>ground and moving at zero MPh..
>
>So in actuality it comes down from space even slower than going up. 
>Yes?  45 min vs 10.
>
>Ok,  same goes with any satellite,,
>
>How come,  going up,,  0 to 17K MPh through the atmosphere, all  is
>fine..  BUT
>
>coming down,,  17K MPh  to 0  unless it has protection  it will  burn
up
>in the atmosphere from friction with the air.
>
>why is it different?
>
>Joe WB9SBD & NSS
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>  
>