The launch of NASA’s Galaxy Evolution Explorer (GALEX) spacecraft
aboard an Orbital Sciences Corporation (OSC) air-launched Pegasus vehicle is
scheduled for deployment over the Atlantic Ocean from OSC’s L-1011 carrier
aircraft on Monday, April 28 at 8 a.m. EDT. This time is contained within a
launch window that opens at 7:50 a.m. and closes at 9:50 a.m. EDT.

The launch begins with the drop of the Pegasus rocket from the
L-1011 over the Atlantic Ocean at an altitude of 39,000 feet at a location
approximately 100 nautical miles offshore east-northeast of Cape Canaveral.
The launch is expected to be visible from the coast. Spacecraft separation
from the Pegasus occurs 11 minutes later. At that time the satellite will
be in a circular orbit of 431 statute miles (690 km) at a 29-degree
inclination.

GALEX will observe a million galaxies across 10 billion years of cosmic
history to help astronomers determine when the stars and galaxies we see
today had their origins. During the course of its two-year investigation,
GALEX will conduct the first ultraviolet surveys of the entire extragalactic
sky, including the first wide-area spectroscopic surveys. This vast data
archive will form a lasting legacy. Rich in objects from galaxies to
quasars to white dwarf stars, it will serve as a resource for the entire
astronomical community.

The Jet Propulsion Laboratory (JPL) is responsible for the project
management of GALEX and built the telescopic instrument. Orbital Sciences
Corporation built the spacecraft bus and is responsible for instrument
integration. The California Institute of Technology is responsible for the
science operations and astronomical data. The Kennedy Space Center is
responsible for spacecraft/launch vehicle integration, countdown management,
launch vehicle engineering oversight and mission assurance.

PRELAUNCH NEWS CONFERENCE

The prelaunch news conference is scheduled for Friday, April 25 at 1
p.m. EDT at the NASA-KSC News Center. Participating in the briefing will
be:

Charles Dovale, NASA launch director
John F. Kennedy Space Center, Florida

Bryan Baldwin, Pegasus launch vehicle program manager
Orbital Sciences Corporation, Dulles, Virginia

Dr. James Fanson, GALEX project manager
Jet Propulsion Laboratory, Pasadena, California

James Sardonia, launch weather officer
45th Weather Squadron, Cape Canaveral Air Force Station

GALEX MISSION SCIENCE BRIEFING

Dr. Richard Fisher, director of Sun-Earth Connection division
NASA Headquarters, Washington

Dr. Christopher Martin, GALEX principal investigator
California Institute of Technology, Pasadena, Calif.

ACCREDITATION

Media needing accreditation should apply written on news
organization letterhead and addressed to NASA Press Accreditations and faxed
to 321-867-2692. Please include full name, Social Security number, birth
date, birth location and citizenship. For media needing badges, all
requests for launch day accreditation must be received by the close of
business Friday, April 25.

LAUNCH DAY PRESS COVERAGE

On launch day, April 28, media representatives will depart to cover
the launch at 6:15 a.m. by government-furnished transportation from the Pass
& Identification Building at Gate 3 on SR 405, east of U.S. 1 south of
Titusville. Media will be taken to the Skid Strip runway on Cape Canaveral
Air Force Station to view the take-off of the L-1011. After aircraft
departure, media will be taken to the viewing room of the NASA Mission
Director’s Center located in Hangar AE on Cape Canaveral Air Force Station.
From there, media may follow the deployment and launch of Pegasus/GALEX.
Media may choose instead to go to the NASA-KSC News Center to follow
progress of the flight.

Assuming a nominal flight of the Pegasus launch vehicle, a post-launch news
conference will not be held. However, launch vehicle and spacecraft
representatives will be available afterward at Hangar AE to informally
answer questions from the media. Media who have elected to return to the
Press Site will be able to teleconference from the News Center conference
room if they so request.

NASA TELEVISION COVERAGE OF PEGASUS/GALEX

This Pegasus launch occurs with a chase plane equipped with a
television camera. There will be live coverage on NASA Television beginning
at 6:30 a.m. EDT and will conclude shortly after spacecraft separation which
occurs 11 minutes after launch. Commentary and audio of all Pegasus/GALEX
briefings will be available on the “V” audio circuits which may be dialed
directly at 321/867- 1220, 1240, 1260, 7135.

The Pegasus/GALEX prelaunch press conference and mission science
briefing will be televised at 1 p.m. on Friday, April 25. Launch coverage
begins at 6:30 a.m. on Monday, April 28.

NASA Television is available on GE-2, Transponder 9C, located at 85
degrees West longitude. These activities will also be webcast and accessed
through the KSC Home Page at www.ksc.nasa.gov.

PEGASUS/GALEX NEWS CENTER

On Friday, April 25, the Pegasus/GALEX News Center at NASA-KSC may
be reached at 321-867-2468 between 8 a.m. and 4:30 p.m. EDT. On launch day,
the NASA-KSC News Center will open at 7 a.m.

PEGASUS/GALEX STATUS

A recorded status report will be available beginning Friday, April
25, and may be reached at 321-867-2525. It is recommended that media check
the status during the weekend to be certain plans for the launch have not
changed.