Space Shuttle Liftoff

[airplane wizard]

Does anyone on here know why the Space Shuttle rolls on it's back during liftoff?

 

[CaravanMan]

The only thing I can think of, which probably isn't correct, is to help those onboard cope with the G-forces since the flight path does seem to be an arc. Again, just a guess.

 

[Rogue5]

From the wikipedia entry:

http://en.wikipedia.org/wiki/Space_shuttle#Ascent

Shortly after clearing the tower the Shuttle begins a roll and pitch program so that the vehicle is below the external tank and SRBs. The vehicle climbs in a progressively flattening arc, accelerating as the weight of the SRBs and main tank decrease. To achieve low orbit requires much more horizontal than vertical acceleration. This is not visually obvious since the vehicle rises vertically and is out of sight for most of the horizontal acceleration.

 

[TrafficInSight]

When it's in orbit it's "on its back." Perhaps rolling on its back right away just prepares it for that so they don't have to expend thruster fuel to turn it over?

edit: nevermind then

 

[FL420]

The only thing I can think of, which probably isn't correct, is to help those onboard cope with the G-forces since the flight path does seem to be an arc. Again, just a guess.

I think you're on to something. I'm guessing the crew would experience positive G's after translation instead of negative G's during the sub-orbital acceleration phase.

 

[kevdog]

I think so they can see the earth during orbit. We already know what happens to it when the fuel tanks explode.

 

[nosehair]

The State of Florida made that a conditional requirement during contract negotiations during the planning phase of Cape Canaveral.
This roll-over is so that the passengers have a full view of the beautiful beaches along the Florida Coast.

Wouldn't it be great if the Airlines would do the same?

 

[bubble]

I heard somewhere that the space shuttle rolls 90 degrees right after liftoff in order to point the antennas toward mission control to maintain good communitcation.

 

[Workin'Stiff]

I had also heard that same thing...

 

[sleddriver71]

I think Rogue5 has the best answer. When they jettison the external tanks, they need to fall "away" from the Space Shuttle. They wouldn't want to run into them.

 

[PDH]

I was told by an astronaut that it was on its back in the event that the shuttle needed to separate from the SRB's and fuel tank. The shuttle would separate and would not have to fly through the path or in front of the tank or SRB's on its descent--it could simply pull away from them and descend simultaneously.

 

[FlightTraker]

Here are the some other reasons...........(sixth paragraph)

http://www.cdli.ca/CITE/sts_ascent.htm



FlightTraker

 

[Rogue5]

After reading the above I do remember seeing some show on the Disco channel or something where it stated one of the main reasons for the roll was to "unload" the wing and thus not over stress it as the orbiter accelerates.

Since the shuttle is in an arcing flight path as it exits the atmosphere, by rolling onto its back it achieves a relatively zero AOA in the climb and greatly reduces any positive or negative forces on the wings.

I think this consideration led to the placement of the antennae on the back of the orbiter.

 

[big_al]

just an FYI, if you hear it on tv, especially the discovery channel, chances are its not true. there are some real winners, those discovery channel contracted writers and producers

 

[Workin'Stiff]

And also to protect those antennae during re-entry...