Delivery: Difference between revisions
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(Created page with "We have a single constraint on the mass we can deliver to the surface intact, and that is Mercury's escape velocity. Even if we can get stationary above the planet we have to...") |
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maximum acceleration: 40m/s^2. | maximum acceleration: 40m/s^2. | ||
create a graph to a soft landing. Killing all the speed as late as possible takes least fuel, | create a graph to a soft landing. Killing all the speed as late as possible takes least fuel, for a given engine. The highest thrust per gram minimizes the mass of propellant. | ||
Revision as of 18:35, 12 July 2020
We have a single constraint on the mass we can deliver to the surface intact, and that is Mercury's escape velocity. Even if we can get stationary above the planet we have to fall and stop. Falling from stationary hits the ground at 4.24 km/s and all of that energy needs killing by engine since there is no atmosphere to brake with. We can perhaps get to stationary without any thrust beyond earth escape velocity, but getting down intact has this minimum unavoidable energy requirement.
Initial limits:
maximum acceleration: 40m/s^2.
create a graph to a soft landing. Killing all the speed as late as possible takes least fuel, for a given engine. The highest thrust per gram minimizes the mass of propellant.