Aug 27 2007, 12:49 PM
Just a question that popped into my mind a couple of days ago. Does anybody know the maximum indicated airspeed that the space shuttle experiences during any phase of flight? I know during launch they throttle back until they pass the point of greatest dynamic pressure (IAS I assume), does anybody know the actual number? If I had to take a guess I would say somewhere around 600-700KIAS.
Aspiring Boeing + Airbus Pilot
Aug 27 2007, 01:29 PM
When the space shuttle is climbing it reaches just less than 1500mph, im not sure what that is in knots though.
Fact - did you know that the space shuttle cruises through space at over 16,000mph!
Aug 27 2007, 04:44 PM
When discussing shuttle vehicle speeds, there are two different modes you must take into account. These are when the shuttle is in the atmosphere and when it is in space. When in space airspeed is irrelevant and orbiter inertial velocity is used. When in the atmosphere IAS is used.
The shuttle accelerates from 0MPH to over 17,500MPH in just 8.5 minutes. At approx 30 seconds into the flight the increasing pressure caused by the increasing speed is counteracted by the decreasing atmospheric pressure. This is called Max Q or Maximum Dynamic Pressure. The engines are throttled back to approx 65% total thrust until approx T+ 50 seconds at which time they are throttled back to 109% or full throttle. This Max Q speed is, coincidentally, approx. 700MPH, or the speed of sound. From throttle up on the pressure on the orbiter from the atmosphere decreases.
Edited 8/28 1110
Incorrect initial post...After SRB seperation the shuttle's main engines continue to accelerate the orbiter to escape velocity at which time the engines cut off. It's at the SRB seperation that IAS is no longer used and inertial velocity is used, approx 4,000 MPH.
Corrected info... Due to the fact that IAS is a function of air pressure as measured by ram air AND the fact that after throttle up the atmospheric pressure is decreasing steadily, IAS is erroneous beyond Mach 1.
Upon completion of the mission, a de-orbit burn of the Orbital Maneuvering System rockets slows the shuttle down to approx 17,000MPH which causes a decrease in altitude. The shuttle reaches the atmosphere at approx. 400,000 ASL and begins re-entry. When the pressure of atmosphere reaches approx. 10PSI, the shuttle ceases to use the OMS and reaction jets and begins using the aerodynamic control surfaces.
In summary, the highest IAS the shuttle reaches is approx 700 MPH on launch.
Aspiring Boeing + Airbus Pilot
Aug 28 2007, 06:45 AM
You sure do know your stuff on space shuttles Glenn.
PS - Seem as though you know so much on this topic it would make sence to ask you: Can a shuttle cruise at 45,000 mph or not, i was told they did but im not sure. Also it was in a book (not an encyclopedia) that they travel at 100,000mph but i don't really believe that or it would only take 2 1/2 hours to get to the moon! could you PM this answer to avoid confusion on this topic.
Aug 28 2007, 11:41 AM
OK, I'll have a guess then. Max IAS approx 600 Kts or so, which will then decrease as the Shuttle accelerates to orbital velocity. As for maximum speed, it depends on where you are measuring from. So as space is virtually a vacuum the only "drag" you'll suffer from is gravity you'll just keep accelerating until you run out of fuel. Speed controls your distance from Earth, you go faster to orbit lower down (the words "Simple Harmonic Motion" spring to mind here) but reduce speed to descend out of orbit . As for the time taken to travel from one body to another, well remember this is a space vehicle and the shortest route from one place to another will be a weird form of curve (as we see it). Think about the route of a ball if you are on bicycle and throw it to another moving cyclist. And then look at the path taken by the ball from different angles. Now put in a wind to represent gravity... Now look at the paths again! Welcome to space travel and remember to listen to your physics lectures when you go to Secondary School.
Aug 28 2007, 02:18 PM
See this chart listing all shuttle missions and their speeds/velocities (MPS and FPS) at certain milestones in the launch...http://spaceflight.nasa.gov/shuttle/refere...reen/ascorb.pdf