Headlines

First Launch of the Century

The launch of an Atlas IIA from Cape Canaveral on February 7, 2000, marked the first government launch of the century. It placed into orbit a DSCS III (Defense Satellite Communications System) B8 SLEP (Service Life Enhancement Program), an improved military communications satellite, the seventh DSCS launched since 1992. The B8 SLEP is the first of four improved satellites that will increase tactical communication. The payload included new electronics that add more power per channel so that ground forces, ships, aircraft, and submarines can use smaller antennas when communicating. The satellite replaces the A1, launched in 1982, in the primary DSCS Western Pacific Theater constellation. Aerospace provided a launch support team at the Cape and supported the launch remotely from locations in Colorado and California. The successful SLEP program has been in operation for four years.

GPS for the Military and Civilians

The fourth in a series of U.S. Global Positioning System (GPS) replacement satellites, GPS IIR4, was launched aboard a Delta II from Cape Canaveral May 10, 2000. Aerospace reviewed the hardware, software, and procedures, and verified that the vehicle was ready for launch. Aerospace developed the fundamental concept of GPS for the Air Force in 1963. Today, GPS, a constellation of 28 navigational satellites that orbit 11,000 miles above Earth, is used increasingly by civilians.

Civilian owners of GPS receivers found their systems significantly more accurate as of May 2, 2000. That day, President Clinton ordered an end to the intentional degradation of GPS satellite signals by the military. The military will, however, retain its right to selectively deny the GPS signals over any given region. Civilians use GPS for many purposes, including search and rescue operations and airplane and ground-vehicle navigation (GPS sensors placed in cars enable drivers to use the Internet to navigate). Unscrambling the signals should benefit the GPS industry, which is expected to grow from $8 million to $16 billion in the next three years.

TIMED to Probe Distant Regions

A remote-sensing spacecraft carrying a payload developed with the help of Aerospace will travel 40 to 110 miles above Earth this year to a little-explored region of the atmosphere. The two-year mission, TIMED (Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics), will begin with a launch from Vandenberg Air Force Base. Its purpose is to study how humans and the sun influence the mesosphere and lower thermosphere and ionosphere. Those regions absorb X-rays and extreme ultraviolet radiation. TIMED will carry the Global Ultraviolet Imager (GUVI), a joint effort between Aerospace and the Applied Physics Laboratory at Johns Hopkins University. Aerospace handled the design, fabrication, and operation of the instrument and was also involved in the software and electronics for the GUVI payload. GUVI will measure profiles of the region's composition and temperature as well as high-latitude auroral energy input.

Clothing That Computes

Soon soldiers in the battlefield may be able to shed some of their 70 pounds of gear and don a lightweight wearable computer that could send and receive life-saving information. For example, a soldier whose vehicle has broken down could be wearing the repair manual. Sound like science fiction? It isn't. Michael Gorlick (in photo), project engineer in the Computer Systems Research Department, constructed suspenders that have electrical conductors woven directly into the fabric. Developed as part of a joint research project between Aerospace and The MITRE Corporation, the suspenders act as a bus and data network for wearable digital devices. Civilian use of wearable computers is also on the horizon. Emergency search and rescue and disaster response teams could be equipped with them. The computers may eventually be carried in pockets, worn on belts, attached to wrists, or worn as brooches and rings. Hardhats and eyeglass frames could also house data networks. Imagine those involved in the meticulous work of satellite assembly having essential information right before their eyes.

Amazing MEMS

Microelectromechanical systems (MEMS), machines so tiny they cannot be seen with the naked eye, are quickly gaining notoriety for their capability and versatility in a variety of areas. MEMS can be used to detect environmental pollutants, monitor the health of a premature newborn, sense an impending car crash and deploy the air bag, and be "woven" into the clothes of soldiers on the battlefield (where the sensors would warn against an attack by chemical or biological weapons). A more aggressive use of MEMS is the potential for manufacturing mass-producible, 1-kilogram-class nanosatellites with microelectronics-processing technology.

More than 30 Aerospace scientists are involved in MEMS research, including Henry Helvajian of the Aerospace Center for Microtechnology and the editor of Microengineering Aerospace Systems. Aerospace researchers sent aloft a MEMS experimental testbed on the space shuttle Columbia last year. Data from 30 of the devices were analyzed to see how the various MEMS performed during launch, orbit, and reentry, compared with their performance in preflight tests. One device, designed and built by Aerospace, contains 15 microthrusters, which act like 15 individual solid rocket motors. The usefulness of MEMS in space has yet to be fully realized, and the analysis by Aerospace was the first systematic testing of MEMS in that capacity. Another experimental MEMS test mission, planned for 2001, will involve the International Space Station.

Miniature Satellites Launched

The tiniest operational satellites ever placed in orbit were launched aboard a new Air Force booster for light satellites January 26, 2000, from Vandenberg Air Force Base. Each satellite weighs less than one-half pound and is slightly larger than a deck of cards. In a project for the Defense Advanced Research Projects Agency (DARPA), Aerospace conceived the mission, designed and built the "picosats," tested their components, and handled flight operations. The primary mission was to demonstrate the use of miniature satellites in testing DARPA microelectromechanical systems (MEMS). The two picosats were positioned in a low Earth orbit after they were released February 6, 2000, from the Orbiting Picosatellite Automated Launcher (OPAL), a satellite built by Stanford University students. The satellites were joined by a tether, which kept them in range of each other for crosslink purposes as they simulated formation flying. Thin strands of gold wire in the tether allowed the U.S. Space Command's Space Surveillance Network to use radar to locate and track the picosats. The mission, concluded on February 10, 2000, was the first of a series of missions designed to validate MEMS technology.

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