# Rocket Launch Question

1. Nov 7, 2007

### IMP

Lets say Mt. Everest was located on the equator. How much more efficient would it be to launch a rocket from the top of this mountain as compaired to a sea-level Florida launch? There would be much less atmosperic drag since you would be starting out 5-miles high. You would be slightly closer to space. The "sling-shot effect" would aid the launch. The rocket motor nozzle could be slightly wider (at higher altitude, wider is better). I am curious to know how much this would help (slightly heavier payload). Would it be 5% more efficient?

Last edited: Nov 7, 2007
2. Nov 7, 2007

### ShawnD

The change in efficiency relies entirely on how high you are trying to go. For example, setting the end point at 10mi high is a lot different from saying you want the rocket to go 20mi high. You absolutely must know the height you are trying to get.

From there you also need to know the relation between air thickness and height, as well as the relation between drag and air thickness. Integrate one into the other to figure out how much drag happens between the starting point and the max height you are trying to get.

How high do you want the rocket to go?

3. Nov 7, 2007

### IMP

Sorry, I should have specified that. Full size rocket (Shuttle, Ariane, etc) to low Earth orbit.

4. Nov 7, 2007

### mgb_phys

The main advantage is getting through the thick lower air + weather.
The Pegasus project launches satelites on boosters from under the wing of a converted airliner at around 40,000ft.

5. Nov 7, 2007

### rcgldr

I assume the airliner is flying east which gives an additional boost to acheiving escape velocities?

6. Nov 7, 2007

### mgb_phys

The launch I saw was going west.
This is either to head into the jet stream and give the ageing L1011 more lift, or since they launch from California it is to point any accident away from a lot of expensive real estate and even more expensive lawyers.

7. Nov 8, 2007

### IMP

If you launched the Shuttle from the top of Mt. Everest, how much more payload could it carry for same amount of fuel?