EP-95 ON THE MOON WITH APOLLO 16
 
 

Introduction to Orbital Science

 

[43] At each landing site on the surface of the Moon, the astronauts' activities are limited to distances of a few miles. In comparison with the total area of the surface of the Moon, the regions explored by the astronauts on foot or with the Rover are minuscule. They are frequently referred to as "point" samples. The desirability of extending our observations to larger areas is obvious. Indeed, several things can be done in orbit about the Moon that will allow us to extrapolate from the data obtained on the surface to the rest of the Moon. One of these things is photography; many photographs have been obtained from the command module on each of the previous Apollo missions. Both the number and quality of photographs obtained from lunar orbit on Apollo 15, and scheduled to be obtained on 16 and 17, have been greatly increased over those of earlier missions.

Several things other than photography can be done from lunar orbit. In these next few sections I will describe them.

The region of the Moon that was examined with orbital experiments on Apollo 15 is shown in figure 55. The coverage for the present mission, Apollo 16, is shown in figure 56. At the time of writing this guidebook (January 1972), the landing site for Apollo 17 had not been chosen. So I do not show the orbital coverage for Apollo 17. Nonetheless, I expect that the total coverage for these three missions will exceed 20% of the Moon's surface for several of the orbital experiments and will exceed 5% for each of them.

Although some photographic tasks will be done in the command module, most of the experiments for the orbital science will be done with equipment located in the service module. The various orbital experiments include the following-a chemical group of three experiments (gamma-ray spectrometer, X-ray fluorescence, and alpha particle spectrometer), S-band transponder, mass spectrometer, several photographic cameras with a laser altimeter, and a subsatellite (with S-band transponder, particle shadows/boundary layer, and magnetometer).

The equipment for the orbital science experiments, carried in the service module, are all housed in a section that is termed scientific instrument module (acronym SIM). The location of the SIM in the service module is shown III figure 57. The location of the equipment for the individual experiments in the SIM is shown in figure 58. The names and addresses of the principal investigator of each orbital experiment are given in Table 5.

 


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FIGURE 55. Orbital path for Apollo 15.

FIGURE 55. Orbital path for Apollo 15. Because the landing site of Apollo 15 was located well away from the equator the command module covered a rather large area of the Moon's surface. Data from the "chemical group" of experiments indicate the distribution of certain elements on the Moon's surface. The coverage of the farside of the Moon, never seen from Earth, is especially valuable. Almost 10,000 photographs were obtained during Apollo 15. If the 8x10 prints were laid side by side, they would extend almost 2 miles. BASE MAP COURTESY OF NATIONAL GEOGRAPHIC SOCIETY.


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FIGURE 56. Orbital path for Apollo 16.

FIGURE 56. Orbital path for Apollo 16. See also caption for figure 55. BASE MAP COURTESY OF NATIONAL GEOGRAPHIC SOCIETY.


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FIGURE 57. Location of Scientific Instrument Module (SIM) in the Service Module, Apollo 15 photograph was taken from the LM with the Moon for background. NASA PHOTO AS15-88-11972.

FIGURE 57. Location of Scientific Instrument Module (SIM) in the Service Module, Apollo 15 photograph was taken from the LM with the Moon for background. NASA PHOTO AS15-88-11972. Sketch shows details and names.


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FIGURE 58.-SIM Bay. Shown here is the location within the scientific instrument module (SIM) of the equipment for each orbital experiment.

FIGURE 58.-SIM Bay. Shown here is the location within the scientific instrument module (SIM) of the equipment for each orbital experiment. The sensors for the gamma ray spectrometer and the mass spectrometer both extend outward on a boom about 25 feet when the instruments are in use. The subsatellite is launched while the service module is in orbit around the Moon; it remains behind in orbit after the astronauts leave lunar orbit to return home. Before the CM is separated from the SM the film cassettes must be retrieved. NASA PHOTO S-72-16862.


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