the cabling, communications, and similar facilities which link the elements of the complex are under contract.

Upon completion, launch complex 39 will provide a two-pad complex with a vertical assembly building, three outfitted LUT's, an arming tower, two crawlers, the crawlerways linking the VAB with the pads, and supporting equipment and structures which make them capable of performing their design functions. The phasing of the operational availability of the facets of this facility is such that scheduled launch requirements can be satisfied.

Flight network.-A most important ground resource is the manned space flight network, which is budgeted and implemented by the Office of Tracking and Data Acquisition so as to meet manned space flight detailed data requirements. The network, together with the Integrated Mission Control Center in Houston and the Launch Control Center at Cape Kennedy, constitute the ground operational support system (GOSS), the system which provides for the gathering of data from or about the spacecraft, for transmitting data and instructions to the spacecraft, and for exercising overall command of the mission. The original network will be modified for APOLLO (fig. 70).

the

Three major changes are required for APOLLO. First, APOLLO spacecraft data system employs a single two-way RF system for all types of data (voice, telemetry, television, and command and tracking). This means that the stations in the network must be equipped to handle this new "unified S-band" system, which offers the advantage of reducing considerably the weight of the instrumentation aboard the spacecraft. Secondly, because of the ranges involved, much larger tracking antennas (85 feet diameter at lunar distances)

FIGURE 70

must be used after the spacecraft has left Earth orbit. Finally, new stations will need to be added at several points on the Earth.

Only a few of the necessary new stations can be located on land. In fact, five new stations on ships must be added because so much of the Earth is water. All required ship support will be provided by the Department of Defense under a special agreement. One of the new ships must be suitably instrumented to cover the insertion into Earth orbit, two to cover the two possible areas where injection into lunar transfer trajectory may occur, and two to handle tracking during the return-to-Earth phase.

A joint NASA-DOD committee is determining the technical configuration of these ships, the degree of support they can provide other programs, and the management procedures which will be employed in their support of APOLLO. Every effort is being made to make them compatible with existing DOD range systems and the requirements of other programs.

Integrated Mission Control Center.-Instrumentation and data systems at the Kennedy Space Center will be grouped as much as possible within a single building, the central instrumentation facility (CIF) in the industrial area. The Launch Control Center (LCC) for the launch phase will be located at complex 29 near the vertical assembly building. Soon after launch, command will be assumed by the Integrated Mission Control Center (IMCC) at Houston (fig. 71). The IMCC, equipped with all the necessary displays, computers, and communications systems (fig. 72), will determine in detail how the flight is progressing, provide data and instructions to the astronauts, assist them in decisionmaking, and assume control of the space

craft in the event it becomes necessary. The IMCC will also contain a simulation system for preflight exercise of all instrumentation system elements to be used during the flight, a most important procedure in assuring mission success.

ADVANCED MANNED MISSIONS PROGRAM

The advanced manned missions program provides guidance to NASA management on decisions regarding the future course of manned space flight endeavors. It develops missions, weighs alternatives, and proposes future projects. It also conducts technical studies to provide information as to the types of missions to be undertaken; the requirements for new systems; the growth possibilities of systems presently being developed; and the possible extension of scope in current programs. Figure 73 shows how advanced manned mission studies span a typical manned space project cycle and how they relate to the advanced technology activities of the Office of Advanced Research and Technology and to the unmanned data-gathering functions of the Office of Space Sciences.

By the time the APOLLO lunar landing has been accomplished, the Nation will have developed the scientific and engineering skills and industrial capability to move ahead into other manned space endeavors. Having developed the basic APOLLO hardware, it will be well equipped to support follow-on programs. Studies to date indicate three major possibilities: expanded lunar exploration, manned Earth-orbiting laboratories, and missions to the near planets.

The broad scientific objective of space exploration is to obtain a better picture of the origin and evolution of the universe, especially the Earth and its solar system. To do this, two classes of observations are required: those focused on present phenomena, and those focused on the evidence of past events.

Studies of phenomena presently occurring in space consist in general of measurements of the space environment, such as radiation, particles, and fields. However, if we desire to study events that have occurred in the past, we are limited to the study of solid objects, for only they "remember" what has happened to them.

There are several reasons why the Moon is a convenient and important extraterrestrial solid body on which such investigations can take place. The most important, aside from the advantage of nearness, is that the Moon's solid surface should preserve one of the best, if not the best, record of the development of the solar system. The major reason for this is the probability that the Moon has never had a substantial atmosphere or hydrosphere. For this reason, the surficial rocks have not been subjected to Earth-type erosive processes that would destroy their original character. Some changes have undoubtedly taken place on the surface as evidenced by the extensive cratering and development of mountains and maria.

Notwithstanding these changes, large segments of the scientific community believe that study of primordial crustal areas on the

Moon should be possible. On Earth we have yet to find crustal rocks much older than 3 billion years. Under present theories of the age of the solar system these determinations leave unaccounted the first billion years of the Earth's development. This period is extremely important because the Earth's oceans, atmosphere, and continents apparently came into being.

Because the Earth-Moon system can be considered as a double planet, there is scientific validity in using a comparative planetology approach to obtain a better understanding of Earth. Studies of the Moon's surface stratigraphic record, subsurface structure, and the many observable surface features of apparent geological significance should increase our understanding of the Earth to a point never before attainable.

Mission definition

Scientific exploration of the Moon will undoubtedly require more than a few landings at isolated points by either unmanned probes or astronaut-scientist teams. As presently conceived, the approved manned and unmanned lunar programs represent just a beginning in lunar exploration. The surface area of the Moon, all of which is potentially accessible, is roughly equivalent to the land area of North and South America combined as can be seen by the relative size of Texas on fig 74. This great size, plus the high cost of a man-hour of exploration, demand that an efficient exploration program be defined and implemented.

As presently conceived, such a program consists of three major activities: (1) a comprehensive study of as much of the Moon's surface as possible using photogeologic and remote sensing methods,