Hi All

Considering how long JIMO will take to get to Jupiter I wonder if aerobraking might be an easier way to get into orbit.

One specific scenario is from Arthur Clarke's "2010: Odyssey Two" in which the "Alexei Leonov" aerobrakes into an Io Transfer Orbit [ITO] after a flight from Earth on a parabolic trajectory. According to my figures that's an initial velocity of 62 km/s [at peri-Jove] reduced to 55 km/s for the ITO - just a mere 7 km/s dv. But Jupiter rotates at ~ 12.5 km/s so it's really 49.5 km/s reduced to just 42.5 km/s.

If the "Leonov" massed 50 tons then that's about 74.25 gigawatts heat dissipated by the shockwave for a 3 gee decceleration. dE/dt = m.v.dv/dt

For a 40 m^2 aeroshell that's a shockwave temperature of ~ 13,500 K ! Gary, is that at all feasible for an ablating aeroshell? Galileo's shockwave was hotter I seem to recall and we know it made it. With that in mind perhaps an NTR powered Jupiter Orbiter/Lander might be a better option than JIMO? It could refuel off indigenous ices just like the "Tsien" had planned in "2010".

Adam

PS - for a parabolic trajectory from LEO to Jupiter some 8.75 km/s dv is needed, make it ~ 9 km/s with gravity losses. To match velocities with Callisto would be another 6 km/s. Hence ~ 15 km/s all up, which is achieveable with an NTR using LH2 propellant.