The Science Of The Viking Missions

The NASA\u27s next missions to Mars are to land two unmanned spacecraft on the surface in 1976 to perform scientific experiments. This pair of missions called Viking consists of two identical spacecraft each launched from a Titan/Centaur in the summer of 1975- Each spacecraft consists of a Lander and an Orbiter combination and together carry 13 scientific investigations. The Orbiter carries its Lander to the planet and then acts as a relay to return the telemetered data to Earth. Following the launches in the summer of 1975\u3e there is an 11-month cruise to the planet. The spacecraft are injected into highly elliptical synchronous orbits about the planet. The periapsis of about 1500 km is selected to be over the appropriate preselected landing site. The missions are separated by about 2 months so that the missions can be handled consecutively. For each spacecraft, after the landing site is certified and the orbit is trimmed, the Lander is released. The nominal landing target is an ellipse about 100 by 500 km. The Lander enters the Martian atmosphere at about 15° traveling about 5 km/sec. The initial deceleration is from the aerodynamic drag of its 12-foot aeroshell. At about 5 km above the surface, a parachute is deployed as the second braking system. At 2 km as sensed by an onboard radar, three retrorockets are fired and the Lander is soft landed onto the surface (see Fig. 1). The scientific experiments aboard the Lander require several months of operation; the nominal length of the mission is 60 days. Power for this period on the Lander is obtained from two 35-watt radioisotope thermoelectric generators. The data from the experiments are telemetered by relay up to the Orbiter and back to Earth or may be telemetered directly from the.Lander to the Earth at a lower rate. Commands to both the Lander and Orbiter will be sent over the deep space net. A tape recorder aboard the Lander will allow storage of data for subsequent transmission, thereby permitting events to be recorded independent of the positions of the Orbiter or Earth

The 1989 NASA-ASEE Summer Faculty Fellowship Program in Aeronautics and Research

The 1989 NASA-ASEE Summer Faculty Fellowship Program at the Goddard Space Flight Center was conducted during 5 Jun. 1989 to 11 Aug. 1989. The research projects were previously assigned. Work summaries are presented for the following topics: optical properties data base; particle acceleration; satellite imagery; telemetry workstation; spectroscopy; image processing; stellar spectra; optical radar; robotics; atmospheric composition; semiconductors computer networks; remote sensing; software engineering; solar flares; and glaciers

Research & Technology Report Goddard Space Flight Center

The main theme of this edition of the annual Research and Technology Report is Mission Operations and Data Systems. Shifting from centralized to distributed mission operations, and from human interactive operations to highly automated operations is reported. The following aspects are addressed: Mission planning and operations; TDRSS, Positioning Systems, and orbit determination; hardware and software associated with Ground System and Networks; data processing and analysis; and World Wide Web. Flight projects are described along with the achievements in space sciences and earth sciences. Spacecraft subsystems, cryogenic developments, and new tools and capabilities are also discussed

R and T report: Goddard Space Flight Center

The 1993 Research and Technology Report for Goddard Space Flight Center is presented. Research covered areas such as (1) flight projects; (2) space sciences including cosmology, high energy, stars and galaxies, and the solar system; (3) earth sciences including process modeling, hydrology/cryology, atmospheres, biosphere, and solid earth; (4) networks, planning, and information systems including support for mission operations, data distribution, advanced software and systems engineering, and planning/scheduling; and (5) engineering and materials including spacecraft systems, material and testing, optics and photonics and robotics

FASAC Technical Assessment Report: Soviet Space Science Research

This report is the work of a panel of eight US scientists who surveyed and assessed Soviet research in the spare sciences. All of the panelists were very familiar with Soviet research through their knowledge of the published scientific literature and personal contacts with Soviet and other foreign colleagues. In addition, all of the panelists reviewed considerable additional open literature--scientific, and popular, including news releases. The specific disciplines of Soviet space science research examined in detail for the report were: solar-terrestrial research, lunar and planetary research, space astronomy and astrophysics, and, life sciences. The Soviet Union has in the past carried out an ambitious program in lunar exploration and, more recently, in studies of the inner planets, Mars and especially Venus. The Soviets have provided scientific data about the latter planet which has been crucial for studies of the planet's evolution. Future programs envision an encounter with Halley's Comet, in March 1986, and missions to Mars and asteroids. The Soviet programs in the life sciences and solar-terrestrial research have been long-lasting and systematically pursued. Much of the ground-based and space-based research in these two disciplines appears to be motivated by the requirement to establish long-term human habitation in near-Earth space. The Soviet contributions to new discoveries and understanding in observational space astronomy and astrophysics have been few. This is in significant contrast to the very excellent theoretical work contributed by Soviet scientists in this discipline