Meterology Satellites in 1972 and 1973 to permit continuous observation of major weather systems, derive wind field data over large areas, and provide rapid capability for widespread meterological data dissemination; and two Earth Resources Technology Satellites for 1972 and 1973 launch to assess the value of remote sensing of Earth resources data from satellites.

In adition to the development of prototype spacecraft to be used for worldwide monitoring of our environment, a number of NASA's centers have been assigned the responsibility of investigating local ecological and environmental problems. They will learn how to interpret and apply the information obtained from satellites by actual determination of ground truth, and in general they will activity support the detailed environmental needs of the assigned local area.

And finally, the last line item is Launch Vehicle Procurement. This activity encompasses a functional support area for centralized procurement of launch vehicles for NASA's automated spacecraft activity. Launch vehicle improvements are undertaken when necessary to improve mission performance or reliability. (SV71-2409).

A broad extension of this launch vehicle activity is the planning for future operational support by the Space Shuttle. The Space Shuttle capability for launching, retrieval, maintenance and refurbishment of satellites can produce fundamental changes in their design and operational concepts. We expect these changes to lead to considerable savings in development and operational costs of future OSSA spacecraft. Further elaboration of this very important subject will be given in the detailed program presentations.

And finally to conclude this overview, I would like to mention some important changes in organization and personnel which have occurred within OSSA since our last review.

In order to provide a more coordinated and effective program, our various Space Biology activities within NASA have been grouped together under one head within OMSF. OSSA has retained only the necessary functions of exobiology and planetary quarantine, and these will report to the Director of Planetary Exploration.

Mr. Oran Nicks has left OSSA to take the position of Deputy Director of the Langley Research Center. His previous position as Deputy Associate Administrator has been filled by Vincent L. Johnson. Consistent with the Congressional desire to reduce NASA personnel, the position of Deputy Associate Administrator for Engineering, vacated by Mr. Johnson, has been eliminated.

Dr. Robert G. Wilson, previously in charge of the Research and Engineering Division Space Programs at the Autonetics Division of North American Rockwell Corporation has joined my staff as Director of Advanced Programs.

Mr. Chairman, the overview I have just presented should aid you in relating the following detailed programs to the total OSSA program; therefore, unless there are any questions, I will now proceed to discuss in detail the four major line items in the FY 1972 OSSA budget. The presentation will be divided into two major parts: Space Science, which includes Physics and Astronomy; Lunar Exploration and Planetary Exploration; and Space Applications, which includes Earth Observations, Communications and Navigation.

PHYSICS AND ASTRONOMY PROGRAMS

PROGRAM OBJECTIVES AND RECENT RESULTS

The Physics and Astronomy Programs are dedicated to increasing our knowledge and understanding of our cosmic environment. We explore our space environment in order to understand its nature and the physical processes that shape it, and to generate the knowledge that will help solve the practical problems facing us on Earth. Exploration and acquisition of knowledge are also important because they contribute to the qualities of the human spirit. Man has always been a questioning and exploring creature, and the great nations of history have been exploring nations. Our great nation must continue to explore the universe and to expand the frontiers of knowledge.

In 1958 the first United States (US) satellite, aptly named Explorer 1, carried a Geiger counter by Dr. Van Allen to study cosmic rays. He discovered trapped electrons and protons in the radiation belts surrounding Earth. This unexpected new knowledge was crucial to the successful operation of communication and weather satellites, which were to come into use only a decade later. As we exploit the discoveries of previous decades to solve today's problems, our generation must contribute to the storehouse of knowledge required to solve the problems of tomorrow. It is in this spirit that we are conducting programs in space astronomy and space physics. These programs are broadly based in terms of the scientific and technical areas covered, and also in terms of the people participating in them. The National Aeronautics and Space Administration (NASA) Centers, industrial laboratories, and academic institutions located in over 40 states and in many foreign countries, are participating in these programs.

Although the programs are broadly based, they are at the same time selective in that relatively few objectives have been chosen from among the many available. In setting priorities we not only consider the intrinsic scientific value, but we also try to expedite those investigations that are most likely to contribute toward practical applications. Because the Sun is an essential part of our ecological system, Sun-Earth relationships is one of these primary areas of study. The role of the Sun as a source of heat and light for photosynthesis is recognized by everyone. What is the role played by the solar ultraviolet and particulate radiations in the control of Earth's extended environment--the magnetosphere and upper atmosphere? About one-half of the proposed effort in the Physics and Astronomy Programs is being devoted to developing the fundamental knowledge needed for answering this and other questions about Sun-Earth relationships.

In 1970 we obtained unique information about the Sun. During the solar eclipse, whose zone of totality included the Wallops Island Launch Range, we launched 31 rockets which carried out a range of observations as illustrated in Chart SG71-2665. Because several active regions were in view on the Sun and a small solar flare occurred, conditions on the Sun during the eclipse were particularly interesting. We found that the area around the Sun glows in the ultraviolet emission of atomic hydrogen (Lyman-alpha). This glow covers an area almost three times the size of the solar disk. The corona was found to be a plentiful source for X-rays which are concentrated over active regions, in contrast to previous assumptions that the corona should not emit many X-rays because of its low density. A plausible explanation for this observation is that energetic electrons are magnetically trapped in the corona and are therefore able to produce X-rays even in a very tenuous medium. The eclipse was also observed with instruments on an Orbiting Solar Observatory (OSO 5). One of these instruments, an X-ray telescope, observed a small solar flare as it was being occulted by the Moon. This observation permitted an accurate determination of the actual size of the X-ray source in the flare to be made. Because of the effect which these radiations have

on the ionization of Earth's atmosphere, these rocket and satellite observations of ultraviolet and X-ray emissions in the Sun's atmosphere (corona) are important. One result of practical interest is the precise effect of this ionization on radio communications.

In addition to the electromagnetic radiation, particles are also ejected from the Sun. These particles travel through the solar system and reach us three to four days afterwards. They interact with Earth's outer envelope, the magnetosphere, and also produce disturbances which can be detected all over the world. A still unexplained puzzle relates to a continuous flow of particles called the solar wind, the method of entry of these particles into the magnetosphere, and their precipitation into and heating of the po ar atmosphere. Instrumentation on Explorer 41 (Interplanetary Monitoring Platform-G) obtained evidence, for the first time, of the entry of particles from Earth's sunward side into its polar regions. A particle spectrometer on the Applications Technology Satellite 5 (ATS 5) (19,000-mile circular orbit) detected clouds of electrons and protons entering from Earth's dark side in the wake or tail created by the interaction of the solar wind with Earth's magnetic field. These results have been explained so far by postulating the existence of a high voltage electric field (50,000 volts) between the sunrise and sunset side of the magnetosphere.

Will this new knowledge gleaned from observing Sun-Earth relationships form the basis for gaining some control over Earth's environment? Will it help us design a radically new power source? Will it be used in an entirely unanticipated manner? As yet we cannot answer these questions any more than Dr. Van Allen was able to predict the specific importance of his explorations prior to the launch of Explorer 1 in 1958.

In late 1969 and 1970 two bright comets offered opportunities that arise only a few times per century. These comets, Tago-Sato-Kosaka and Bennett, came at a time when the Orbiting Astronomical Observatory 2 (OAO 2) telescope could be trained on them to observe their ultraviolet emissions. These observations led to the discovery of a large envelope or atmosphere of atomic hydrogen surrounding these comets and of the intense radiation in the ultraviolet from hydroxyl (OH) molecules. One interpretation of these observations is that the probable source for the hydrogen and hydroxyl is the breakdown of water vapor by light from the Sun. In this view, an important and major constituent of a comet might be ice or a snow-like material with dust embedded in it. The mass and extent of

the hydrogen cloud of Comet Bennett was determined by observations with an instrument on the Orbiting Geophysical Observatory 5 (OGO 5), while the spacecraft was 50,000 miles from Earth and outside the hydrogen surrounding Barth (geocorona). Chart SG1-2669 shows the new picture of a comet that has emerged. In addition to the coma and tail, comets have a newly discovered component and envelope of hydrogen gas. This hydrogen cloud around Comet Bennett was estimated to weigh over two million tons and was over five million miles wide.

In March 1970 we observed, for the first time from space, the explosion of a star. This event, called a nova, occurred about 3000 light years from Earth in the constellation Serpens, thus the name Nova Serpentis. In astronomical terms Nova Serpentis was quite close and could be observed in great detail. As illustrated in Chart SG71-2672, a relatively insignificant star increased greatly in size and became very much brighter than it had been before. Such events have been observed repeatedly in visible light from the ground. Nova Serpentis is the first exploding star we were able to ob erve in the ultraviolet and infrared radiations which do not reach the ground. In response to an alert from ground-based observatories, OAO 2 was programmed to observe the ultraviolet emission from Nova Serpentis. The emission lines observed tell us about conditions in the hot expanding gas produced in the Nova explosion. The envelope cools as it expands; thus, several months after the initial explosion, the emission is primarily in the infrared. By using instrumentation on the NASA Lear Jet, we were able to observe this emission in infrared light after Nova Serpentis had dimmed substantially in visible light. These observations confirm that matter from these stars is actually thrown off and becomes a part of the interstellar medium.

The research programs in physics and astronomy are being carried out by a variety of means. A particular investigation utilizes the simplest effective tools available. Where complex or heavy instruments are required observatory-class spacecraft, such as the newly proposed High Energy Astronomy Observatories (HEAO), are used. Other observations are conducted with smaller Scout- or Delta-launched satellites called Explorers. Sounding rockets, balloons, and airplanes are employed when orbital flight is not required. Experiments carried on other NASA flight programs also make important contributions to the objectives of the Physics and Astronomy Programs. For instance, the Skylab carries a major set of solar telescopes, Apollo Telescope Mount (ATM), as well as a number of smaller experiments. All of the flight programs are supported by essential ground-based observations and by laboratory, research, and theoretical studies.