Apollo 12 Ocean of Storms

 


 

The Apollo 12 flight was the second landing on the moon, November 19, 1969. This landing is notable because it was a precision landing near the Surveyor 3 lunar probe which had landed there 2 years earlier. The Surveyor probe was the target of a lunar EVA where the astronauts removed some parts for return to earth. Scientists wanted to examine them for the effects of long term exposure.

 

There are two EL3D scenarios for this landing:

 

  • Short Flight P66

This is a short flight in program P66. It starts at about 500. The LM is descending at about 17fps and moving forward at about 70fps. The AGC program is P66. The Primary Navigation Guidance System (PGNS) switch is set to Attitude Hold. This is allows manual control of the LM attitude. The throttle is set to Automatic and the computer handles all of the throttle functions. The astronaut may click the Rate of Descent (ROD) switch up or down to initiate 1fps per click commanded changes in descent rate. Pressing F3 will show the historic landing site at the edge of Surveyor crater. A large arrow sets over the top and a green outline of a LM is on the surface.

 

  • Long Flight P64

The longer flight begins farther up range and at about 8000. The LM is moving at about 500fps and descending at 140fps. The AGC program is P64. The Primary Navigation Guidance System (PGNS) switch is set to Auto. That means the autopilot is engaged. The DSKY display is flashing indicating it is expecting a PRO command. Pressing PRO (keyboard *) stops the flashing and allows for manual redesignation of the landing site. The angle to the computed landing site is displayed in the right two digits of Register 1 on the DSKY. Aligning this number with the Landing Point Designator (LPD) on the window will show the intended landing point. If this is not acceptable one can nudge the controller in the desired direction and the computer will recalculate the landing site, issue commands to the autopilot and display the new angle on the DSKY. As the LM slow pitches forward the LPD angle will change a little bit. Also, very near the landing site the LPD angle will be so far below the window that the LPD angle will go off scale. The two digits to the left on Register 1 of the DSKY indicate the time left for LPD redesignation.