Moonlander is a simuation-type program and the first software release from Orion. The object of Moonlander is to get your landing craft from its orbit with the mothership 120 miles out in space and land safely on the planet surface. This must be accomplished using a strictly limited amount of fuel with which to control your descent and execute final touchdown manoeuvres.
There is an initial 60 second orbital countdown period after which you automatically unlock - if you have not already done so manually. The Automatic Gravity System (AGS) controls your descent rate from T + 0 to about T + 120 seconds with 10 second burn sequences and takes you to within about five miles of the planet surface. You can select to switch to manual override at any time during this descent but at T + 120 seconds you *must* take over. At 200 feet or below, the display is switched automatically to the Inter Orbital/Relay scan for final touchdown.
During the simulation, the television screen displays the appropriate monitors and scans. Essential information such as elapsed time, height above planet, speed (of descent, but if you overdo the retroburns you can find yourself going back up!) and quantity of fuel remaining is given. The trick is to use just the right amount of fuel to descend quickly but in control to the planet surface; it is all too easy to run out of fuel, or misjudge your speed, and crashland. Helpfully, there is a touchdown practice routine.
Variations in the initial factors ensure that each mission is slightly difference. Success takes practice and a soft landing it entirely dependent on pilot skill.
Moonlander is written in Basic. I found the instructions somewhat jargonistic and difficult to understand, but once I had worked out how to operate the simulation and mastered the various monitor and scan displays, I found it quite a challenge. It certainly isn't easy to get that darned moonlander down without creating a new crater in the lunar surface. Just one more go should crack it...