Apollo 15 Part 3: ALSEP (Apollo Lunar Surface Experiment Package) Deployment
Apollo 15 was the ninth crewed Apollo mission and the fourth to land on the Moon. It was also the first of the J-missions designed for a longer stay on the moon and was the first flight with the lunar rover.
ALSEP: consisted of 2 scientific instrument packages capable of transmitting back to earth for 1 year. Data from the package was used to derive information regarding composition and structure of lunar body, its magnetic field, atmosphere and solar wind. ALSEP power supplied by radioisotope thermoelectric generator (RTG). The fuel capsule was stowed in a graphite cask on the side of the descent stage. The capsule was removed from the cask and installed in the RTG on the moon.
Crew:
David Scott (CDR): 3rd and last spaceflight (Gemini 8, Apollo 9)
Alfred Worden (CMP): only spaceflight
James Irwin (LMP): only spaceflight
Dates:
Launch: Kennedy Space Center Pad LC-39A July 26, 1971
Lunar Landing: Hadley-Apennine July 30, 1971
Lunar Launch: August 4, 1971
Recovered: North Pacific Ocean August 7, 1971
Apollo Lunar Module Descent Stage Quadrants:
Quad 1: folded lunar Rover (LRV)
Quad 2: ALSEP (Apollo Lunar Surface Experiments Package)
Quad 3: Rover aft tool pallet and payload pallet
Quad 4: MESA (Modularized Equipment Stowage Assembly)
Lunar Module “Falcon”
-Only LM that landed on the moon piloted by an Air Force pilot (all others
piloted by Navy Pilots).
-Landing hit hard but within limits and landing in most challenging terrain
(local terrain slope was 11 degrees). Landing gear designed to land on
slopes up to 12 degrees.
-Final rest angle was 6.9 deg pitch up & 8.6 deg right roll.
-Longer descent engine nozzle buckled on landing but not due to impact
but due to a buildup pressure in the nozzle due to thrusting in close
proximity the the lunar surface.
-All lunar modules have gear legs that only stroke once with no rebound.
Falcon gear legs stroked 1 inch on landing except for the front gear
which stroked 3 inches. But in the final rest position, the front gear was
not touching the ground.
Lunar Rover:
Manufacturer: Boeing/General Motors
Electric Motor: 0.25 HP DC motor on each wheel - Transmission: 80:1
harmonic drives
Range: 57 miles
Weight: 460 lbs Earth, 76 lbs Moon
A15 total time driven: 3h 2 min
MESA: deployed from a D-Ring near the porch. MESA contained, extra PLSS batteries, LiOH cartridges, TV camera, still cameras, geology tools, food, film, and sample containers.
J-Mission Modifications Most of the modifications involved making more room in Quad 1 for the LRV and Quad 4 for the enlarged MESA and additional water and GOX tanks. Modification to Lunar Module for J-Missions include:
S-band erectable antenna moved from Quad 1 to Quad 4
relocated Explosive Device relay box and pyro battery to provide Quad 4
clearance for additional water and GOX tanks
modified MESA support in Quad 4.
batteries and electrical control assemblies relocated from Quad 1 and 4
to -Z bulkhead (aft gear leg)
modified RCS plume deflectors (shortened) to provide protection to
enlarged MESA and LRV addition.
modified ascent stage support structure for increased provisions.
cleared all previous equipment from Quad 1 for LRV
insulated docking tunnel to reduce cabin heat leakage
added controlled bleed vent for descent super critical Helium
added 10 inch fixed nozzle extension for descent engine to provide
additional efficiency at full thrust
removed descent propellant tank balance lines
saved 25 lbs by removing thruster isolation valves - added additional
battery to -Z bulkhead (along with the 3 other relocated batteries). This
gave a total of 5 batteries
added capability to recharge PLSS
added 1208 lbs of usable descent propellant (18,697 lbs total propellant)
added 3rd sample return container
Acronyms:
-ALSEP: Apollo lunar surface experiments package
-CCIG: cold cathode ion gauge
-HFE: heat flow experiment
-LRRR: lunar ranging retroreflector
-LSM: lunar surface magnetometer
-PSE: passive seismic experiment
-RTG: radioisotope thermoelectric generator
-SIDE: supra thermal ion detector experiment
-SWS: solar wind spectrometer