Sunday, October 01, 2006

How efficient is Orion?

The question comes up. Also on the web. And blogs.

The are four types of efficiency to consider.

1- Most simply; payload fraction, the part of the launched mission that is useful.

a) Orion - 40+% is common for easy missions.
i) 880 Ton test vehicle 34%: 300 tons to 300 mi orbit
ii) 4000 Ton Interplanetary
one) 40% 1600 tons to orbit
two) 30% 1200 tons to Lunar landing
three) 20% 800 tons to lunar surface and back
four) 20% 800 tons to mars orbit and back
five) 5% 200 tons to Venus orbit then Mars orbit then Earth orbit.

iii) Advanced Interplanetary 10,000 tons
one) 61% 6100 tons to orbit
two) 57% 5700 tons to Lunar landing
three) 53% 5300 tons to lunar surface and back
four) 53% 5300 tons to mars orbit and back
five) 45% 4500 tons to Venus orbit then Mars orbit then Earth orbit.
six) 13% 1300 tons to Enceladus and back

iv) 10m 1963 Orion Design from Ga-5009
300 day Mars mission from earth orbit and back 103,300 ft/sec
6.4%: 1145 mt gross 72.8 mt payload

v) 10m 1963 Orion Design from Ga-5009
450 day Mars mission 97,355 ft/sec
8.3%: 73 mt payload 880 mt gross

vi) 20m 1963 Orion Design from Ga-5009
450 day Mars mission 72,850 ft/sec
26%: 300 mt payload 1141 gross


b) Shuttle - Cargo 1.6% (LEO) to 0.8% (ISS) , non cargo missions do a
little better.

c) Apollo can be broken down into fundamental tasks, that contribute to the
total payload. Oversimplifed the payload fraction is 25/3000 = .83 %, this
combination is invalid, but the breakdown
will be useful when looking at energy.

i) Place the 15 metric ton Lunar Module on Luna
2) Move the 5 metric ton Ascent Stage to Lunar orbit.
3) Return the 5 metric ton Command Module to earth.

d) Viking - 632,970 Gross mass
i) 2328 kg Orbiter in LMO : 0.36 %
ii) 572 kg Lander on Mars : 0.09 %

e) Voyager 1 - 0.114 % 721.9 kg / 632,970 Gross mass


2- ISP - A measure of efficiency developed early in rocket research.

Project Orion - Compared to other high performance options .

3- Energy efficiency - Especially apealing to children of the seventies.

a) Project Orion - A detailed analysis of the 880 ton Orbital Orion Test Vehicle.
450 KT yields 4.87 kt. of orbital energy. 1.66 KT of cargo energy.
Efficiency is therefore .37% percent.

b) Shuttle - The external tank starts with 1.2 Kt of , the SRB's with 3 for
a total of 4.2 Kt. The ISS cargo energy is .11 Kt, for an efficiency of 2.5%.

c) Viking - The 572 kg Lander on Mars has .007 Kt more potential energy than
before launch. The 2 metric ton orbiter has 0.03 Kiltons of extra energy.
Launch fuel: 530 Tons mixed, energy to be calculated.

d) Voyager 1 - Solar Altitude 14,919,000,000 km, v 17,147 m / sec
mass 721.9 kg, total potential and kinetic energy added by mission: .19 KT
Launch fuel: 530 Tons mixed, energy to be calculated.



4- Cost efficiency - Most complicated, but most important.
Dyson 8 million ton Super Orion was as efficient as 5 cents per pound.

Relationships and examples to be calculated...

----------------
Constants


From: To: [m/s] MegaJoules/KG

Earth surface Low Earth Orbit 9300 43
Low Earth Orbit GTO 2500
GTO GEO 1500
GTO Earth escape 700
Earth escape Low Lunar Orbit 700
Earth escape Mars Transfer Orbit 600
LEO Mars surface 4800
LEO Solar escape 8700
Lunar Lunar Lunar surface 1600
Mars surface Low Mars Orbit 4100
Mars capture orbit Mars low-energy 900
Low Mars Orbit Phobos Transfer 900

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