| MISSION_DESCRIPTION |
Mission Overview
================
Apollo 15 was launched on 6 July 1971 UT 13:34:00 on a Saturn V
rocket from Kennedy Space Center. Lunar orbit insertion took place
on 29 July 1971 UT 20:05:47. The Lunar Module (LM) landed on the
Moon on 30 July 1971 UT 22:16:29, near the Hadley Rille and
Apennine Mountains (26.13 N, 3.63 E), while the Command/Service
Module (CSM) orbited the Moon. The lunar ascent module launched
from the Moon on 2 August 1971 UT 17:11:22. The command module was
returned to Earth on 7 August 1971 UT 20:45:53.
The astronauts on Apollo 15 were commander David Scott, command
module pilot Alfred Worden, and lunar module pilot James Irwin.
Three excursions on the first Lunar Roving Vehicle (LRV) lasted a
total of 18 hours and 35 minutes and traversed 27.9 km. The lunar
surface stay-time was 66.9 hours. During the stay, the Apollo
Lunar Surface Experiment Package (ALSEP) was placed and activated,
and 77.31 kg of rock and soil samples were collected. The duration
of the lunar orbit was 145 hours for a total of 74 orbits. The
small sub-satellite was deployed from the CSM on 4 August 1972 UT
20:13:19 and left in lunar orbit for the first time.
Surface Operations
==================
Scott and Irwin made three moonwalk extra-vehicular activities
(EVAs) totaling 18 hours, 35 minutes. During this time they covered
27.9 km and collected 77.31 kg of rock and soil samples. The LRV was
used to explore regions within 5 km of the LM landing site. This
was the first time a vehicle of this type had been used, and its
performance on the lunar terrain was very successful. Two hours
after landing the cabin was depressurized and Scott performed a
standup EVA for 33 minutes, describing and photographing the
surrounding terrain from the LM upper hatch. The first moonwalk EVA
was on 31 July from 13:13:10 UT to 19:45:59 UT, during which time
the LRV was unloaded, deployed, and driven. Photographs of the
lunar surface were taken and geologic samples were collected from
the LM site and during the three geological traverses. The traverse
on the first EVA covered 10.3 km to the edge of Hadley Rille to
Elbow Crater and near St. George Crater and back to the LM, where a
core sample was taken from three meters below the surface. The
ALSEP was deployed at the end of the traverse. On the second EVA,
on 1 August from 11:48:48 UT to 19:01:02 UT, the LRV was driven on
a 12.5 km traverse southeast along the base of the Apennine
Mountains near Index, Arbeit, Crescent, Dune, and Spur craters and
back to the ALSEP site. On the third EVA on 2 August from 08:52:14
UT to 13:42:04 UT the LRV was driven a total of 5.1 km west to
Scarp Crater and northwest along the edge of Hadley Rille and back
east across the mare. The LM lifted off the Moon on 2 August at
17:11:22 UT after 66 hours, 55 minutes on the lunar surface.
Surface Experiments
===================
The Apollo 15 astronauts performed and deployed many experiments on
the lunar surface along with the geologic studies, sample return,
and surface photography:
- The Solar Wind Composition experiment collected samples of
solar wind on a large piece of foil which was returned to
Earth;
- The Soil Mechanics Investigations studied the physical
properties of the lunar regolith using observations recorded by
video and audio and a surface penetrometer which recorded data
on a drum which was returned to Earth.
Other experiments were part of the Apollo Lunar Surface Experiments
Package (ALSEP) which was emplaced at the landing site by the
astronauts. The instruments, connected by cables to a central
station which controlled power and communications, ran autonomously.
Data collected was converted to a telemetry format and transmitted to
Earth. Many of these experiments returned data until September 1977,
when the ALSEP network was turned off due to budgetary constraints.
The Apollo 15 ALSEP instruments consisted of:
- A Passive Seismometer, designed to measure seismic activity and
physical properties of the lunar crust and interior;
- A Lunar Surface Magnetometer, designed to measure the magnetic
field at the ALSEP site;
- A Solar Wind Spectrometer, designed to measure protons and
electrons from the solar wind and magnetotail plasma impinging
on the lunar surface;
- A Suprathermal Ion Detector, designed to measure positive ions
reaching the lunar surface to provide data on the plasma
interaction between the solar wind and the Moon;
- A Heat Flow Experiment, designed to measure the rate of heat loss
from the lunar interior and the thermal properties of lunar
material;
- A Cold Cathode Ion Gage, designed to measure the density of
neutral particles in the tenuous lunar atmosphere;
- A Laser Ranging Retroreflector, designed to reflect laser pulses
from Earth back to their point of origin to make accurate
determination of the distance between Earth and the Moon;
- A Lunar Dust Detector, designed to assess the long-term effects
of the lunar dust, radiation, and thermal environment on solar
cells.
Orbital Science Experiments
===========================
Investigations were also carried out from lunar orbit in the Apollo
15 Command and Service Module. Hand-held photography was performed
from the command module, and a suite of instruments operated from
the Scientific Instrument Module (SIM) in the Service Module,
comprising:
- Metric and Panoramic cameras to take photographs of the lunar
surface from orbit;
- A Laser Altimeter using reflected laser pulses to profile the
topography of lunar surface;
- A Gamma-ray Spectrometer Experiment to measure gamma ray
emissions from the lunar surface to determine composition;
- An X-ray Fluorescence Spectrometer Experiment to measure
secondary X-ray emissions from the lunar surface to determine
composition;
- An Alpha Particle Spectrometer Experiment to measure radon gas
emissions from the lunar surface;
- An S-Band Transponder Experiment designed to carefully track
the CSM orbit and measure the lunar gravity field;
- An Orbital Mass Spectrometer Experiment to study the tenuous
lunar atmosphere and search for active lunar volcanism;
- A Bistatic Radar Experiment used measurements of S-Band and VHF
reflections to probe electromagnetic and structural properties
of the lunar surface;
- A Subsatellite released from the CSM into lunar orbit with
instruments to measure the Moon's gravity field, magnetic
field, and distribution of charged particles.
Additional experiments were also performed in lunar orbit and
during the cruise between Earth and the Moon:
- The Ultraviolet Photography Experiment took images of Earth
and the Moon in UV;
- The Gegenschein Photography Experiment took images of the
reflections from dust particles at the Moulton point;
- The Window Meteoroid experiment studied micrometeoroid impacts
on the Apollo 15 Command Module heat shield windows to obtain
information about the mass flux of micro-meteorites.
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