Aerospace Teams Contribute to Delta, GPS Launch Success

CAPE CANAVERAL, Fla. (2/20/01) -- Aerospace team members on the East and West coasts provided prelaunch, launch and early-orbit support in the successful launch of a Delta II rocket Jan. 30 from Cape Canaveral Air Force Station.

Inserted into orbit was a Global Positioning System (GPS) Block IIR satellite, GPS IIR-7.

The launch was the first from the Cape this year.

The satellite was equipped with a first-flight Nuclear Detonation Detection System Analysis Package (NAP), which will support many future GPS IIR spacecraft.

Review Team

Aerospace employees led a review team engaged from vehicle acceptance testing through mission- readiness review.

Aerospace GPS personnel worked with the spacecraft contractor to clear the space vehicle with respect to several ground power interruptions and an environmental control outage before launch.

After launch an early-orbit team stationed at Schriever Air Force Base, Colorado, and supported by Aerospace subsystem experts assisted Space Command in guiding the spacecraft through a series of required maneuvers.

Thermal Issues

During this period the team addressed several thermal issues and executed a preplanned contingency maneuver to maintain component temperatures at acceptable levels. Key thermal performance assessments were made by Aerospace personnel.

Aerospace team members also provided launch readiness verification.

A substantial launch vehicle mission-assurance effort was performed to verify several first-flight vehicle configuration items and related mission design changes.

The mission was the first Air Force flight of the Enhanced Flight Program (EFP) software, which operates within the Redundant Inertial Flight Control Assembly (RIFCA) to control the Delta in flight.

A newly deployed version of the Delta Command and Data Processing System ground control software was used to perform launch control.

New Analyses

Several new launch-vehicle system analyses were necessary because of NAP and changes to the mission design.

Aerospace personnel reviewed loads, separation, stress, thermal and venting analyses updated for the NAP vehicle configuration. Control stability, controllability, and placard analyses were reviewed to verify the mission design.

Aerospace developed a new scientific trajectory simulation tool -- SCISIM -- to model the EFP and Delta launch-vehicle dynamics.

Team members developed the baseline simulation, updated SCISIM to model the new design trajectory, and used the tool to validate the EFP mission constants and the new EFP load-relief algorithm.

HILS

This was the first Aerospace use of the medium launch vehicle Hardware-in-the-Loop Simulation (HILS) tool, developed to validate the Delta flight software.

HILS executes the as-flown Delta EFP software and mission constants in real time and enhances Aerospace mission-assurance capability for the Delta software. HILS was used to validate the EFP and GPS IIR-7 mission constants.

An Aerospace review team verified that the RIFCA unit was ready for flight after factory test deficiencies and test anomalies indicated some concern for the unitÕs integrity.

While Aerospace personnel supported launch operations at the Cape, other company teams supported operations at the Space Launch Telemetry Acquisition and Reporting System -- STARS -- facility in El Segundo, Calif.

Countdown Delayed

A last-minute vehicle equipment installation problem delayed initiation of the terminal countdown by nearly an hour, causing one of the most challenging Delta II countdowns in recent launch history because of the compressed timeline.

Aerospace personnel assisted in resolving last-minute issues to maintain a successful countdown and liftoff within the short launch window.

The team effort resulted in a nominal flight sequence and injection of the GPS into a highly accurate transfer orbit.