July 30, 2003

SCISAT-1 ACE

Status   (processing notes)

At Vandenberg Air Force Base, Calif., the SCISAT spacecraft was mated to the Pegasus launch vehicle, beginning on Monday, July 28, at 8 a.m., and completed by 10 p.m. The fourth flight simulation is scheduled for today. The payload fairing will be installed Aug. 4. Installation onto the Pegasus transporter is scheduled for Aug. 6 followed by rollout to the hot pad and mating to the L-1011 carrier aircraft on Aug 9.

SCISAT-1 weighs approximately 330 pounds and will be placed in a 400-mile-high polar orbit at an inclination of 73.9 degrees.

The SCISAT mission will investigate processes that control the distribution of ozone in the upper atmosphere and measure the chemical processes that control the distribution of ozone in the Earth's atmosphere, particularly at high altitudes. The data from the satellite will provide Canadian and international scientists with improved measurements relating to global ozone processes and help policymakers assess existing environmental policy and develop protective measures for improving the health of our atmosphere, preventing further ozone depletion. The mission is designed to last two years.

SIRTF

Status   (processing notes)

Installation of the flight battery was completed on July 24. Final observatory closeouts and preparation for mating to the payload attach fitting will begin Sunday, Aug. 3. Transportation to Pad 17-B is scheduled for Aug. 10.

Cryogenic servicing of the observatory with liquid helium was performed on July 22. The erection of the Boeing Delta II launch vehicle on Pad 17-B began on Friday, July 18, with the erection of the first stage. Erection of the nine solid rocket boosters began on Saturday, July 19 and was completed on Friday, July 25. The second stage was hoisted atop the first stage on July 28. The fairing was hoisted into the launch pad clean room area on July 29.

The Flight Program Verification, an integrated test of the vehicle and the spacecraft, is scheduled to occur Aug. 12. The payload fairing will be installed around SIRTF atop the Delta II on Aug. 14, followed by servicing with cryogenic helium.

SIRTF is the fourth and final element in NASA's family of orbiting "Great Observatories." All objects in the universe with temperatures above absolute zero (-460 F) emit some infrared radiation, or heat. Infrared wavelengths lie beyond the red portion of the visible spectrum and are invisible to the human eye. Most infrared light emitted by celestial objects is absorbed by Earth's atmosphere. Scientists rely on orbiting telescopes such as SIRTF to capture data on celestial objects and phenomena that are too dim, distant or cool to study using ground-based telescopes or by other astronomical techniques.

Project management of SIRTF for NASA is by the Jet Propulsion Laboratory. The Observatory was built for NASA by Lockheed Martin and Ball Aerospace.

The launch period extends to Sept. 17.

GP-B

Status   (processing notes)

Functional testing of Gravity Probe B and the initial liquid helium cryogenic servicing was performed last week in spacecraft processing hangar 1610. Also, the telescope stray-light test was performed last week.

Gravity Probe B arrived at Vandenberg Air Force Base on July 11 from the Lockheed Martin plant in Sunnyvale, Calif. It was transported to NASA spacecraft processing hanger 1610 located on North Vandenberg Air Force Base. The spacecraft was unloaded from its transporter, placed onto an assembly and test stand, and the soft shipping cover was removed.

The erection of the Boeing Delta II launch vehicle at Space Launch Complex 2 is currently scheduled to begin on Sept. 15 with the erection of the first stage. Attachment of the nine strap-on solid rocket boosters in sets of three is scheduled for Sept. 16-18. The second stage is planned for mating atop the first stage on Sept. 19. Gravity Probe B will be transported from the spacecraft hangar to Space Launch Complex 2 Oct. 29, and hoisted atop the second stage. The Delta II fairing will be installed around the spacecraft on Nov. 5 as part of final preparations for launch.

Gravity Probe B is a relativity experiment developed by NASA's Marshall Space Flight Center, Stanford University and Lockheed Martin. The spacecraft will test two extraordinary predictions of Albert Einstein's general theory of relativity that he advanced in 1916. Gravity Probe B consists of four sophisticated gyroscopes to be launched into a 400-mile-high orbit for a mission lasting 18 to 24 months.

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