Apollo 11

 

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 The Apollo 11 flight was the first landing on the moon, July 20th, 1969.

 

This EL3D mission has two unique features not present in other missions.  During the P64 flight there was a program alarm which is modeled in EL3D.  In addition the short flight (P66) has a special sound file option.  Please see the Special Function sections for descriptions.

 

There are two EL3D scenarios for this landing:

 

• Short Flight P66
• The short flight is the default flight for non-registered versions of EL3D.  It starts at about 500’, just east of West Crater.  Eagle 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.  On the actual mission Neil Armstrong pitched forward and landed farther downrange.  Obviously he clicked the ROD switch ‘up’ to reduce his descent rate.  He kept a high forward velocity until he cleared the West Crater and began slowing down to land.  Pressing F3 will show the historic landing site.  A large arrow sets over the top and a green outline of a LM is on the surface.  The large horizontal velocity near the ground caused the Altitude and Velocity lights on the DSKY light display to come on.  This meant the radar could not provide reliable velocity information but since Neil was flying visually it didn’t matter.

 

Special Function  Before starting the flight there will be a check box that becomes visible when you have selected the Short Flight P66 scenario.  This check box is called Test-11 and is in the Sound Settings section.  If you check this box the sound you will hear is a continuous stream of real-time audio from the actual Apollo 11 landing.  The ‘triggers’ of altitudes and speeds no longer applies and this sound plays the audio non-stop.  This option allows you to try to mimick the audio altitudes and speeds with your own flight.  See how close you can get your flight to the actual flight.

 

• 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.

 

Special Function  On Apollo 11 there was a little trouble during the P64 flight segment.  Apparently the rendezvous radar was trying track the CSM even though it wasn’t needed for this stage of flight.  This additional processing overloaded the computer and caused several program alarms to occur.  Two of them occurred in the previous flight segment (P63) but one more occurred during P64.  When this happened the DSKY blanked and the alarm code showed in Register 1.  During P64 a 1201 alarm occurred.  It was easily ‘fixed’ by resetting the computer.  In EL3D just press the “.” Key on the Numpad.  The computer will restart.  Note: For those that may have seen the HBO mini-series From the Earth to the Moon, you may recall this part of the story.  However they “hollywooded” it up a bit with alarm bells and the Master Alarm light.  In actuality the AGC program alarms were not connected to the Master Alarm.  Of course the LMP was intensely scanning the DSKY so it really wasn’t necessary.