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Bruce
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Joined: Tue May 18, 1999 2:46 am

Thrust Reverser On A Space Shuttle?

Thu Oct 26, 2000 3:05 pm

Would this be technically possible? You all know how a thrust reverser works - directing the flow of exhaust against the airflow, causing lots more drag and helping to slow down.

So, why can't they have a small rocket jet near the shuttle's nose (actually they do - they are used in space as steering jets), and fire them when in the atmosphere. They would be firing FORWARD, going against the airflow, and theoretically it shouldd help to slow down the airspeed. Right? Or, have a thrust-reverser type of device on the main engine so if they fired it, it would go against the airflow.

When you think about it this seems like it should work. Maybe some of you tech-types can shoot down (no puns intended) my theory.
Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
 
mls515
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Joined: Mon Jun 26, 2000 5:56 am

RE: Thrust Reverser On A Space Shuttle?

Thu Oct 26, 2000 5:42 pm

The weight and fuel it would take up would be better used elsewhere.
 
AC_A340
Posts: 2196
Joined: Wed Sep 08, 1999 12:01 pm

RE: Thrust Reverser On A Space Shuttle?

Thu Oct 26, 2000 9:44 pm

The reason they don't have them on the main rockets is because the space shuttle actually glides into the atmosphere. The rockets have nothing to do with the descent or landing. And the fuel could be better used elsewhere.
 
Guest

RE: Thrust Reverser On A Space Shuttle?

Thu Oct 26, 2000 10:32 pm

It would be possible to do, but because the shuttle weighs so much (273Klbs) it would have to be a large amount of thrust, which increases the weight even
more (engine + fuel), destroys the aerodynamics of wherever it was located, etc.

The thrust-reverser concept on the main engines is moot, because once the external tank is jettisoned on ascent, the main engines are not used again (they are fueled by the tank). You know how big the tank is, and that powers those 3 engines for only 8.5 minutes before the fuel is depleted. Think of how much larger the shuttle would have to be to do the thrust-reversing just from a fuel standpoint......

Interesting question though!
 
pmk
Posts: 609
Joined: Wed May 26, 1999 10:07 am

RE: Thrust Reverser On A Space Shuttle?

Thu Oct 26, 2000 11:45 pm

>"So, why can't they have a small rocket jet near the >shuttle's nose (actually they do - they are used in >space as steering jets), and fire them when in the >atmosphere..."

1. Landing space isn't a problem in California.
2. The Landing Strip in Florida is plenty long
3. They do, it's called a parachute.
4. The PRCS (Primary Reaction Control System) is used in a WEIGHTLESS ENVIRONMENT, the thrust is about 10 LBS!!! These rockets are hypergolic, meaning they combust on contact, the chemicals used in the RCS are VERY nasty. The EPA would have a fit, imagine the phone call.

"... you wanna use the rockets, okay... I see yeah, the exaust kills living tissue on contact...really, it also causes cancer, Well I'll have to get back to you..."

In short, there's no need for thrust reversing equipment. Please remember this small rule, for every pound of anything lifted in space it takes 10 pounds of propellant.

Peter
 
CPDC10-30
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RE: Thrust Reverser On A Space Shuttle?

Thu Oct 26, 2000 11:45 pm

Installing a drag parachute does the same job with much less weight and complexity.
 
akelley728
Posts: 1965
Joined: Tue Dec 07, 1999 12:35 pm

RE: Thrust Reverser On A Space Shuttle?

Fri Oct 27, 2000 12:46 am

In addition to the drag parachute, the shuttle also has a speed brake to facilitate deceleration while landing. It's quite cool actually, The rudder splits into two halves to serve as a speed brake.

Think of the speed brake on the F-28 & Bae146 where the tail splits to form a brake. The rudder speed brake on the Shuttle follows the same principle.