Space Sciences

Taken by the Galileo spacecraft in June 1996, these enhanced color images highlight details on the surface of Io, Jupiter's volcanic moon. The reddish deposits are believed to result from high-temperature explosive volcanism, which also leads to the release of large amounts of sulphur and oxygen into space near Jupiter. SwRI researchers are particularly interested in how such surface activity affects Jupiter's magnetosphere and aurora. (Photo courtesy of Jet Propulsion Laboratory.)

Research and development in space sciences and engineering has long been an Institute strength. Teams of scientists and engineers formulate concepts, design and manage complex hardware and data systems, develop advanced spaceborne instrumentation, and address theoretical aspects of space physics and planetary astronomy. This expertise has been successfully applied to the development of scientific payloads aboard space shuttles, satellites, and sounding rockets.

A Delta launch vehicle carried NASA's Polar satellite into Earth orbit in February 1996. Polar will provide the most comprehensive measurements to date of plasma mass and energy transport near the Earth. The payload includes three unique space plasma instruments developed and fabricated at the Institute. The Thermal Ion Dynamics Experiment (TIDE) and Plasma Source Instrument (PSI), developed at SwRI for the Marshall Space Flight Center, will allow study of low-energy ions flowing out of the Earth's polar and auroral regions. TIDE is 100 times more sensitive to low-energy ion fluxes than its predecessors. Operating with PSI, which is designed to neutralize electrostatic charges on spacecraft, TIDE allows long postulated outflows of plasma from the Earth's ionosphere to be routinely observed for the first time. The Toroidal Ion Mass Spectrometer (TIMAS), carrying a data processor developed at SwRI, measures higher energy plasmas with overlap at the highest end of the TIDE energy range. Institute scientists are participating in analysis of the high-quality data being returned by TIDE and TIMAS.

For NASA's Lunar Prospector Discovery Mission, scheduled for launch in 1997, the Institute is developing high-voltage power supplies, data processing electronics, command and data handling electronics, and a command timer system. The Discovery program is an example of NASA's approach to flying smaller, less expensive missions to the planets and moons of the solar system. To provide information regarding the origin and evolution of the Earth and its moon, Lunar Prospector will use remote sensing to determine the moon's composition, crustal structure, and magnetic field.

Over the past year, SwRI has led a multinational team of scientists and engineers in the final development stages of the Cassini Plasma Spectrometer (CAPS), which will investigate the composition and dynamics of plasma in Saturn's magnetosphere. Calibrations of the CAPS plasma sensors and time-of-flight mass spectrometer are demonstrating excellent performance levels. Cassini will be launched in October 1997 on a trajectory to Saturn. After a seven-year cruise and flybys of Venus, Earth, and Jupiter, Cassini will reach Saturn late in 2004. Cassini will then orbit Saturn for four years and execute numerous flybys of Titan, the rings, and a dozen of Saturn's other satellites.

SwRI scientists are developing the Cassini Plasma Spectrometer (CAPS) to investigate the composition and dynamics of plasma in Saturn's magnetosphere. The CAPS team recently delivered an engineering model and is now assembling and testing a flight model to be launched on a trajectory to Saturn in October 1997.

As principal investigator institution for the first of the Medium-class Explorer space missions, the Institute will be responsible for all aspects of the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission. IMAGE will use new neutral atom imaging techniques to map the charged particle populations of the Earth's magnetosphere. Combined with a radio frequency sounder and an array of ultraviolet imagers, IMAGE will enable researchers to see the structure of the magnetosphere in three dimensions for the first time. This knowledge may enable researchers to understand "space storms" -- magnetospheric disturbances in the solar wind that can damage spacecraft, disrupt communications, and lead to power blackouts. SwRI is responsible for the complete IMAGE spacecraft and its operation, as well as for building one of the neutral atom imagers and the central instrument data processor, through which all of the instruments will communicate with the spacecraft and the ground. IMAGE is scheduled for launch in late 1999.

Four experimental techniques will help carry out a NASA program to provide the first global images of key regions of the Earth's magnetosphere as they respond to variations in the solar wind. Radio plasma imaging, extreme ultraviolet imaging, far ultraviolet imaging, and neutral atom imaging (from left) will yield information about magnetospheric plasma sources. SwRI is leading the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) investigation, slated for launch in late 1999.

SwRI has been selected to provide plasma sensors for two new space missions to comets and asteroids. The Miniaturized Optimized Smart Sensor (MOSS) is the basis for the Plasma Experiment for Planetary Exploration (PEPE), which has been selected for flight on NASA's Deep Space 1 mission. PEPE is being developed with Los Alamos National Laboratory, with launch to Comet Temple 2 planned for early 1998.

Based on the MOSS design and the technical expertise SwRI will gain on PEPE, SwRI was chosen by NASA and the European Space Agency to provide an ultracompact Ion Electron Spectrometer (IES) plasma sensor for the Rosetta mission to Comet Wirtanen, to be launched in 2003. The IES will weigh only 900 grams and use less than one watt of power while providing an ion/electron spectrometer capable of viewing 60 percent of all possible directions and covering energies up to 30 keV. These mass and power resource levels are less than 20 percent of those for comparable instruments flown previously in space.

The Plasma Experiment for Planetary Exploration (PEPE) is one of the most advanced plasma sensor instruments ever to fly. Developed with Los Alamos National Laboratory, PEPE draws ion and electron particles inside to measure their energy, direction of arrival, and mass. This cutaway view shows (from top) an electron sensor, deflection electrodes, and an ion time-of-flight sensor. The lower portion contains five electronic boards.

In addition to the IES, the SwRI Alice ultraviolet (UV) spectrograph has been selected for flight on Rosetta. Alice will generate high resolution UV spectra to measure the composition of gases released by Comet Wirtanen and to track the comet's activity as it orbits the Sun. These measurements and other studies could provide insight into the origins of the solar system. The Institute will also provide novel high-speed circuitry for a reflection time-of-flight mass spectrometer that is part of the ROSINA instrument on the Rosetta mission. The ROSINA project is headed by the University of Bern, Switzerland.

NASA has awarded SwRI a two-year grant to collaborate with Northrop Grumman Corporation on the development of a Mass Spectrograph on a Chip (MASC) that can be used to explore planetary atmospheres. SwRI is leading the overall system design of detailed ray-tracing studies of MASC particle optics and the design of a specialized gas filter/concentrator/sampling system conceptually similar to a gas chromatograph. The goal is to build a medium resolution spectrograph with a sensitivity of 0.1 ppm in a device weighing 600 grams. This device is expected to be faster, less expensive, an order of magnitude smaller, and to require less power than existing mass spectrographs, making it useful for small spaceflight missions as well as for certain military and environmental applications.

The Extreme Ultraviolet Spectrometer (EUVS) sounding rocket payload developed at SwRI launched its fourth mission in July 1996. The primary objective was to perform a detailed investigation of Venus' thermospheric extreme ultraviolet emissions as a follow-on to SwRI's 1994 and 1995 flight investigations. During the last year, several improvements were made to the payload to increase its sensitivity by 50 percent and to increase the spectral resolution to more than twice the resolving power of the first Venus flight. The increased measurement capability of the EUVS allows it to obtain state-of-the-art UV spectra of comets and planets.

Institute scientists maintain an active program in outer planet research, including theoretical modeling and observations, with recent emphasis on photochemical and auroral processes on Jupiter and Saturn. Data suggest that the Saturnian aurora is responsible for a high-latitude haze layer. More observations and data analyses are planned for late 1996. SwRI also continued to monitor Jupiter's X-ray emissions using an orbiting astronomical satellite. Besides the more powerful auroral X-rays, emissions are now seen coming from the planet's mid-latitudes, indicating the presence of substantial numbers of inwardly drifting energetic ions from Jupiter's radiation belts. Scientists expect observations planned for late 1996 will support measurements made by the Galileo spacecraft, which began a series of orbits around Jupiter in late 1995.

SwRI has developed the first module of a miniaturized multimission spacecraft control system. The Miniaturized Optimized Processor for Space, or MOPS6000, is one-fifteenth the size of a typical spacecraft computer. It measures 3.25 x 3.25 x 1.5 inches and contains a commercial RAD6000 central processing unit, power input, data input/output, and communications capabilities. MOPS6000 operates at about 25 million instructions per second. Development is under way on the second module of the miniaturized system -- the Space Adaptable Memory Module, or SpAMM. SpAMM provides dense, scaleable, nonvolatile gigabyte mass memory in a small, lightweight package. It uses high-density multichip modules and staked memory dies to produce a memory density of 84 megabytes per cubic inch. MOPS6000 and SpAMM will be combined with miniaturized military-standard interface modules to provide versatile, full-capability command and data handling systems for flight missions that use small spacecraft.

Institute engineers recently completed development of an ultracompact spaceflight computer called MOPS6000 that delivers up to 25 million instructions per second. The 32-bit processing system includes solid state memory and input/output devices. A complementary system, the Space Adaptable Memory Module, is currently under development.

The Institute is developing a RAD6000-based processor system for the Gravity Probe B relativity gyroscope experiment. Gravity Probe B is being developed by NASA and Stanford University to test two unverified predictions of Einstein's general theory of relativity. The experiment will monitor small changes in the direction of spin of four gyroscopes contained in a satellite orbiting 400 miles over the Earth's North and South Poles. Changes in the gyroscopes' motion will allow Stanford researchers to probe how space and time are warped by the presence of the earth, and also to investigate how the Earth's rotation drags space-time around with it. These effects have profound implications for the nature of matter and structure of the universe. The SwRI-developed processor system will control spacecraft functions, oversee the gyroscope system, and collect data from the experiment's sensors.

The Institute has begun construction on the first of 15 custom computer systems bound for the International Space Station Alpha (ISSA). Based on the RAD6000 processor, the furnace facility control units aboard ISSA include 128 megabytes of memory, more than most large workstations and with similar performance. The units will control up to four high-temperature furnaces used on the space station for microgravity research. The furnace facility is scheduled for launch in late 1999.

SwRI has developed an advanced data acquisition and control system for the Optical Properties Monitor, a multipurpose in-space optical laboratory for the study of materials including thermal control surfaces, optical materials and coatings, and solar power materials. The optical laboratory will be aboard the Russian Mir Station on a scheduled January 1997 flight. During this mission, selected materials will be exposed to low earth orbit and the Mir-induced environment for in situ monitoring and post-flight analyses of the effects of these environments on the materials. The data acquisition and control system will be used to direct electromechanical operations, including filter wheels, lens banks, and sample carousels. The system will also collect and store the data.

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