Headlines

Wanda Austin Appointed President and CEO

Wanda M. Austin became the sixth president and chief executive officer of The Aerospace Corporation January 1, 2008. William F. Ballhaus Jr., the corporation's previous president, in his announcement of her appointment praised her "technical and management experience and her proven leadership skills" as well as her extensive knowledge of the corporation and the programs it supports. Austin has a Ph.D. in systems engineering and has served Aerospace for nearly 30 years, most recently as senior vice president of the corporation's National Systems Group in Chantilly, Virginia.

In addition to her distinguished work with Aerospace, Austin has received many awards and citations for her contributions to the profession outside the corporation. Her latest awards include election to the National Academy of Engineering in February and presentation of the NASA Public Service Medal in March. Membership in the National Academy of Engineering is a professional distinction among the highest an engineer can achieve. The academy cited Austin for leadership in the engineering and integration of national space intelligence systems. NASA's Public Service Medal is reserved for those who have made exceptional contributions to its mission. NASA praised Austin for her service as a member of the NASA Advisory Council. For more on Austin, see the profile in this Crosslink issue.

String of Successful Launches Continues

An Atlas V successfully launched from Vandenberg Air Force Base March 13, 2008, carrying a National Reconnaissance Office payload into orbit. It was the first Atlas V to launch from Vandenberg and the first launch of 2008. Two days later, a Delta II, carrying a GPS IIR-19(M) satellite, successfully lifted off from Cape Canaveral Air Force Station. It was the first Air Force launch from the Cape this year. The two launches continued the streak of consecutive successful national security space operational launches, bringing the total to 58.

Ray Johnson, vice president of The Aerospace Corporation Space Launch Operations, congratulated both Atlas V and Delta II teams for their successful launches. He called the Atlas V launch "a perfect mission" and thanked the Vandenberg Aerospace team for its work of several years to get Space Launch Complex 3E (SLC-3E) ready to support the Atlas program. The complex was significantly modified for this next generation of space launch vehicles. Crews extended the height of an existing 210-foot mobile service tower and umbilical tower by 30 feet each, lengthened the service tower's hammerhead, and installed a new 60-ton bridge crane.

(courtesy of United Launch Alliance)

The crews also built a new launch exhaust duct, fabricated a new fixed launch platform, installed a new water system for acoustic suppression, and modified the launch services building. Other tasks included construction of a new heating, ventilating, and air-conditioning (HVAC) building and electrical substation, improvements to the physical security system, expansion of the complex's fuel storage and loading systems, modifications to the mobile service tower's platforms, and installation of a new umbilical tower lighting mast and umbilical booms. Aerospace was heavily involved in this effort by providing systems engineering support. "The resulting SLC-3E is arguably the best space launch facility in the world," said Joe Wambolt, principal director of the Aerospace Western Range Directorate.

Software Uploads Cause GPS IIR Anomaly

The Aerospace Corporation was part of a team of Air Force and contractor personnel that determined the cause of six instances of anomalous navigation signals broadcast by GPS Block IIR satellites during October 2007. Navigation data uploads from the control segment induced upsets in the onboard mission data unit processors, according to John Berg and Karl Kovach of the Aerospace Navigation Division, who described the anomalies and their prompt resolution.

"GPS operations and engineering personnel responded to these anomalies in an outstanding manner—rapidly diagnosing the anomaly, quickly developing a thorough understanding of the mechanism by which the anomaly was induced, and expediently changing the control segment software to completely preclude any reoccurrence of the anomaly," said Berg. It turned out that the uploads that induced the processor upsets exceeded a constraint that was not documented in the space vehicle's upload format specification.

Five GPS Block IIR satellites and one Block IIR(M) satellite experienced the anomalies from Oct. 8 through 10 that caused outages lasting approximately 2 to 12 hours. With the exception of the first two anomalies, which overlapped, the anomalies affected only one satellite at a time and were limited to payload operations and functions. According to Kovach, the satellite orbit, attitude control, and command and telemetry functions were not affected, nor was the payload hardware.

"Once the problem was clearly understood, the chosen course of action was to slightly modify the control segment's Block IIR upload software to prevent the problem. Since the modified code was installed, there have been and will be no further upload anomalies related to this problem," said Kovach.

Aerospace Navigates with New M-Code GPS Satellites

The successful launch of the sixth GPS Block IIR-M satellite on March 15, 2008, has placed enough modernized satellites on orbit to provide regular intervals of four-in-view visibility at The Aerospace Corporation's headquarters in El Segundo, CA. On March 26, 2008, the Aerospace engineering staff used a software-defined GPS receiver developed in-house to compute real-time navigation solutions using the new modernized military signals. John Langer, principal director for GPS User Systems, believes this is the first time that a navigation solution was generated exclusively from the M-code signal. While still a laboratory technology demonstration, the event "marks a major milestone in the development of the modernized GPS system," he said.

The new M-code is designed to preserve the United States's asymmetric advantage in military navigation, Langer said. "It's specifically designed for more sophisticated levels of electronic warfare than previous military signals." All military signals are designed to resist electronic attack, but the M-code is significantly more robust. "Using a technique called spectral separation, we can provide additional power to the military without interfering with civil use," he said. "It enhances jam resistance, and it enables us to deny adversarial use of the civil signal in a local theater of interest while retaining a powerful jam-resistant signal for the military."

Kevin King, Jason Hsu, Alan Choy, and Alberto Arredondo with the FPGA card hosting the software-defined GPS receiver used to navigate with M-code signals.

To ensure four satellites in view anywhere on Earth requires a constellation of 18 or more satellites, so it will be some years before the GPS M-code Initial Operating Capability will be complete. Nonetheless, the current six GPS satellites broadcasting M-code are sufficient to provide four-in-view coverage for intervals of ten minutes or more at select locations. This is enough to support a robust test campaign, Langer said.

Langer noted that Aerospace was part of the team that designed the M-code signal, and participated in the government procurement of the satellites and the ground systems. He said he hopes to organize a small conference at Aerospace focusing on early access to M-code so that other research organizations can exchange insights and push the technology a little further. "I believe that this effort will build momentum behind the GPS modernization effort and ultimately be a good thing for the GPS modernization programs," he said.

Aerospace Studies Errant Satellite

A single modified tactical Standard Missile-3 (SM-3) launches from the USS Lake Erie to shoot down an errant military satellite (courtesy of US Air Force).

The Aerospace Corporation Center for Orbital and Reentry Debris Studies (CORDS) looks at the growing issue of space debris and hazards associated with the reentry of spacecraft into the atmosphere. The center also develops techniques to mitigate collisions among space objects on orbit, according to William H. Ailor, center director.

Although some debris from reentering objects does survive reentry, most objects are never found or reported. Most commonly, debris lands in water or in uninhabited areas. According to the center's studies, there are no known injuries caused by space debris, to date. Only one case was reported of a person "struck" by debris: a lightweight fragment of debris brushed the shoulder of a woman in Oklahoma in 1997.

Recently, an out-of-control spy satellite falling toward Earth threatened to unload 1000 pounds of hydrazine on the planet. To prevent that from happening, the U.S. Navy shot down the satellite on Feb. 20 with a missile fired from the USS Lake Erie. The Pentagon's analysis of the debris field showed that the satellite's hydrazine-filled fuel tank had been destroyed by the missile and that no hazardous debris had landed on Earth. Wanda Austin, Aerospace president and CEO, said that Aerospace provided data on space debris prior to the shoot-down of the satellite and analytical support to several customers who were involved in the activity.

Researchers are aware of only one instance in which hazardous materials survived reentry and were encountered in Earth's surface: In 1978, debris from the Soviet satellite Cosmos 954 landed in Canada. Some of the debris was radioactive. It was cleaned up with no injuries reported.

To Spring 2008 Table of Contents