Earth shine and in low level light near the terminator, and other lunar surface areas of prime scientific interest. In addition, photography of particular parts of the cosmos of interest to astronomers was conducted. A bistatic radar experiment examined the lunar surface electrical properties and the average upper layer depth and surface roughness. It is too early to discuss the scientific results from Apollo 14, but there is no question that this has been by far the most fruitful scientific mission. We anticipate a large variety of kinds and sizes of lunar rocks and soil, estimated to be approximately 42 kilograms in weight. The geophysical instruments in the ALSEP are all working well and in concert with those of the Apollo 12 ALSEP left on the Moon some 15 months ago. Both passive seismometers recorded the same moonquake or large meteorite impact two days after the astronauts departed. The McDonald Observatory in Texas successfully detected the Laser Ranging Retro-reflector just a few hours after it was deployed on the lunar surface. The portable magmetometer used by the astronauts indicated the presence of a local magnetic source. This may be extremely important scientifically. Various photographic tasks were accomp'ished to observe the low light phenomena of our solar system and galaxy. Photographs of the Descartes area were also taken to aid in the planning for one of the forthcoming missions. NEXT MISSIONS In 1970, based on operational and both short and long term funding considerations, the agency reluctantly concluded that a reduction of two Apollo flights should be made. Thus the remaining series of Apollo flights 15, 16, and 17 will be concluded in 1972. We are making every effort to ensure that the remaining Apollo missions obtain the highest feasible scientific returns through operational and hardware improvements and the most careful selection possible of landing sites and scientific payloads. Our recent decision to delay Apollo 17 for six months will ensure that sufficient time is aavilable to develop those experiments that were originally planned for Apollos 18 and 19. As stated earlier, there is no question now that the Moon is quite a heterogeneous body. The Apollo 11 and 12 missions have shown that sites which appear geologically similar are capable of producing quite different results when actually visited. Future tentative lunar landing sites have been selected for geologically different provinces which will allow us to study the widest possible variation of characteristics and formations and thus to better evaluate theoretical models of the origin and history of the Moon. A significant increase in Apollo capability will be introduced for Apollo 15 and subsequent missions, with attendant increase in scientific return. Block changes in hardware will allow the astronauts to remain on the lunar surface for up to 66 hours-an increase of 100 percent; furthermore, these changes will allow the landed scientific payload to be doubled to approximately 1,200 pounds. Increased range and efficiency of surface operations will result from improved suit mobility, improved life support system, and a lunar roving vehicle. Finally, CSM changes will allow for up to 16 days total flight duration. This evolving technology of lunar exploration reaches a peak during the last three missions-the most sophisticated and comprehensive of the entire series. Twenty-two new surface and orbital experiments have been selected to fly in the Apollo 15 through 17 program. Most of the orbital experiments will be contained in Bay I of the Service Module (Chart MA71-5033). High resolution panoramic photography, metric photography, and laser altimetry will contribute to study of the lunar size, shape, and surface topography; and to study of the interrelationship between gravitational field and lunar surface features. A variety of sensors will remotely examine the chemical and physical properties of large areas of the lunar surface. Apollos 15 and 17 will deliver small subsatellites to lunar orbit for monitoring the variation of magnetic fields and interplanetary charged particle streams in the vicinity of the Moon. The data will define electrical properties and internal physical characteristics of the Moon. The subsatellites will be equipped with transponders which will allow for refinement and extension of mass anomaly data. They will function in lunar orbit for many months after the manned portion of the mission is completed. One of the more intriguing new surface experiments to be carried on Apollo 17 is the tidal gravimeter (Chart MA71-5035). This instrument is designed to measure tidal movements on the lunar surface. It also has the capability of detecting gravitational waves travelling through space. Recent Earth experiments may have detected such waves originally predicted by Einstein, but the inter ference from man-made and natural sources make this experiment very difficult to conduct on Earth. On the Moon, without such interferences, the sensitivity can be increased a thousandfold. Proof of the existence of gravitational waves would represent one of the most important fundamental discoveries of modern times— a discovery with far reaching implications. Greatly increased surface mobility will be provided to the astronauts by the lunar roving vehicle (Chart MA70-5890). This vehicle will have a total range of 90 kilometers and will carry both astronauts plus approximately 80 kilograms of instruments for exploration and collected specimens. The Apollo 15 launch has been scheduled for July 1971 with the Hadley/ Apennine area as its target (Chart MA71-5028). The Apennine mountains form the southeastern edge of the Imbrium basin and rise up to 3 kilometers above the mare surface. The collection and examination of material from this area is a prime objective of the mission. A second important objective is to study and sample the Hadley Rille, which resembles the serpentine meander of a terrestrial river and has long puzzled observers. The origin of sinuous rilles is enigmatic but probably involves some type of fluid flow and/or collapse. The study of the process of sinuous rille formation may yield data on the history of lunar volatiles. A prime new experiment of this mission is the heat flow experiment to be placed in holes drilled about 3 meters into the surface. The measurement of heat flow from the interior of the Moon is a fundamental geophysical measurement needed to shed light on the present internal constitution of the Moon as well as on its history and evolution. In addition to other experiments, another passive seismometer and magnetometer will be deployed to continue the establishment of a network of these instruments in an attempt to unravel the baffling lunar interior. On Apollo 15 a third Laser Ranging Retroreflector will be deployed. (Chart MA70-7594). The reflecting surface of this array will be three times larger than the reflectors deployed on Apollo 11 and will have four times the optical efficiency. Many observatories do not have telescopes of sufficient size to range on the two earlier instruments. The full exploitation of the emplaced reflectors will require an extended sequence of lunar ranging measurements from a number of observing stations around the world. With the deployment of the large (300-corner) array on Apollo 15, international cooperative observing programs with observatories on each continental landmass become a realistic possibility. Other countries indicating the desire to range off the reflector include the Soviet Union, France, Japan, and Australia. A number of others have expressed interest. Specific sites for the last two missions have not yet been chosen. The selection is an evolving process involving scientists and engineers from within NASA as well as other prominent lunar scientists outside of government. A review is conducted after each mission and whenever new operational and scientific information is obtained. Final selection will not be made until operational schedule con. siderations require it. From a large number of logical candidate sites, ther are three that are considered at this time to be prime for Apollo 16 and 17 (Chart MA71-5037): 1. Marius Hills Region-A series of domes and cones located west and northwest of Crater Marius (Chart MA71-5026). They seem to be analogous to volcanic complexes on Earth that display a spectrum of rock compositions and ages. The variety of geologic units suggests that the volcanic activity was extensive and produced a series of volcanic land forms reflecting different rock types. 2. The Descartes Area-A central lunar highland area west of Mare Nectaris. The landing site stands astride two major highland units of Imbrium age (Chart MA71-5027). The first is a hilly, grooved terrain that is similar to some terrestrial volcanic regions, and the second is a highland plains-forming unit. Knowledge of the extent of differentiation in such highland volcanic complex will be of particular value in understanding lunar volcanism and its contributions to the evolution of the lunar highlands. Determination of composition and age of the highland plains material will add to our knowledge of the processes that have modified large areas of the lunar surface. 59-311 0-71-No. 2, pt. 3- 6 |