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Payload to LEO? |
 Nov 10 2006, 06:08 PM
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#1
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Junior Member  Group: Members Posts: 81 Joined: 25-February 05 From: New Jersey Member No.: 177  |
Not exactly sure where to put this, but how would I go about calculating the paylad of a given launch vehicle to LEO? I always see people saying things like, "well, this gives you x tons to LEO, add another SRB and you get 2 more" - how do I calculate this? Is there a program I could get hold of?
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"Too low they build, who build beneath the stars." - Edward Young |
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Nov 10 2006, 07:31 PM
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#2
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Founder Group: Chairman Posts: 14457 Joined: 8-February 04 Member No.: 1 |
I don't know of a program to work it out - it's probably a more complex simulation to get accurate figures than Joe Public could manage (although perhaps using something like Orbiter one could simulate a fairly close approx.)
Most of the figures are out there for current or near-future LV's already though...they have to be in a commercial launch context so people can know what they're looking at www.astronautix.com is a great starting point, and hunt for Launch Guidelines or Payload Guides etc as PDF's at various LV manufacturers websites ( Ariane, Starsem, Pegasus, Atlas V, Delta IV, II all out there I think ) which give extensive versbose launch capacity specification. Doug |
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Nov 10 2006, 08:04 PM
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#3
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Junior Member Group: Members Posts: 81 Joined: 25-February 05 From: New Jersey Member No.: 177 |
QUOTE (djellison @ Nov 10 2006, 07:31 PM)  I don't know of a program to work it out - it's probably a more complex simulation to get accurate figures than Joe Public could manage (although perhaps using something like Orbiter one could simulate a fairly close approx.) Most of the figures are out there for current or near-future LV's already though...they have to be in a commercial launch context so people can know what they're looking at www.astronautix.com is a great starting point, and hunt for Launch Guidelines or Payload Guides etc as PDF's at various LV manufacturers websites ( Ariane, Starsem, Pegasus, Atlas V, Delta IV, II all out there I think ) which give extensive versbose launch capacity specification. Doug But clearly Orbiter has a mathematical basis on which it makes these calculations? Astronautix does have a lot of figures but not for new launch vehicles. -------------------- ----------------------------------------------
"Too low they build, who build beneath the stars." - Edward Young |
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Nov 10 2006, 08:06 PM
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#4
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Founder Group: Chairman Posts: 14457 Joined: 8-February 04 Member No.: 1 |
Well - not a set of calculations...it's just a simulation of what goes on.
Best place to start would be to google for 'The Rocket Equation'  Doug |
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Nov 11 2006, 11:09 AM
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#5
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Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
To do an accurate calculation, you need to know the sea-level thrust and specific impulse of first stage engines, second stage vaccuum <more or less> thrust and impulse, third stage etc.. their mass fractions, burn profile, etc etc etc... that's to get a good (maybe 10%) approximation.
The Devil is in the Details. |
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