TI-57 Lunar Lander ?

[Thomas Okken]

I'm guessing he doesn't remember, because it can't be done. If you free-fall until just before impact, you end up falling with a speed of 85 at an altitude of 27.5. Burning 90 units of fuel at that point kills your speed, but only once you're at altitude -15. Splat.

You need two burns, and I believe the optimum is to free-fall until you're falling with a speed of 80 at an altitude of 110, then burn 15 units so you're falling at a speed of 70 at an altitude of 35; then burn 75 units, killing your speed at altitude 0.