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STS-121: The mission
Tony Ceccacci, the lead shuttle flight director for STS-121, provides a highly informative day-by-day preview of Discovery's mission using animation and other presentations. Then Rick LaBrode, the lead International Space Station flight director during STS-121, explains all of the activities occurring onboard and outside the outpost while Discovery visits.

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Detailing the EVAs
Discovery's STS-121 mission to the International Space Station will feature two scheduled spacewalks and perhaps a third if consumables permit. Spacewalkers Mike Fossum and Piers Sellers will test whether the 50-foot inspection boom carried on the shuttle could be used as a work platform for repairing the heatshield and conduct maintenance chores outside the space station. Tomas Gonzalez-Torres, the mission's lead spacewalk officer, details all the three EVAs in this pre-flight news briefing.

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STS-121 program perspective
A comprehensive series of press briefings for space shuttle Discovery's upcoming STS-121 begins with a program overview conference by Wayne Hale, NASA's manager of the shuttle program, and Kirk Shireman, the deputy program manager of the International Space Station. The two men discuss the significance of Discovery's mission to their respective programs. The briefing was held June 8 at the Johnson Space Center.

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Exploration work
NASA officials unveil the plan to distribute work in the Constellation Program for robotic and human moon and Mars exploration. This address to agency employees on June 5 was given by Administrator Mike Griffin, Associate Administrator for the Exploration Systems Mission Directorate Scott Horowitz and Constellation Program Manager Jeff Hanley.

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Exploration news briefing
Following their announcement on the Exploration work assignments to the various NASA centers, Mike Griffin, Scott Horowitz and Jeff Hanley hold this news conference to answer reporter questions.

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Mercury-bound probe flips sunshade toward the Sun
MISSION STATUS REPORT
Posted: June 22, 2006

The MESSENGER spacecraft performed its final "flip" maneuver for the mission June 21. Responding to commands sent from the MESSENGER Mission Operations Center at The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., through NASA's Deep Space Network antenna station near Goldstone, Calif., the spacecraft rotated 180 degrees, pointing its sunshade toward the Sun.

The 16-minute maneuver, designed to keep MESSENGER operating at safe temperatures as it moves closer to the Sun, wrapped up at 9:34 a.m. EDT, with successful reacquisition of signal from MESSENGER's front-side antenna. The spacecraft was 196.5 million kilometers (122.1 million miles) from Earth and 144.6 million kilometers (89.8 million miles) from the Sun when the maneuver occurred.

MESSENGER had been flying with its back to the Sun since a March 8 "flop," allowing it to maintain temperatures within safe operating ranges at Sun distances greater than 0.95 astronomical units (1 AU is Earth's distance from the Sun). Mission plans call for the spacecraft to keep its sunshade facing the Sun for the remainder of its cruise and science orbital operations around Mercury.

"Initial indications look very good" says MESSENGER Mission Operations Manager Mark Holdridge, of APL. "Spacecraft temperatures are coming down as expected and all systems and instruments are nominal."

The team will now turn its attention to preparing for the first Venus flyby on October 24. "We have mission simulations and flight tests coming up to test particular operations that will have to occur during the Venus flyby," Holdridge says. "There will be a 57-minute solar eclipse during the October operation, so we will so be testing the flight systems in the flyby configuration to verify they will behave properly during the eclipse period."

On August 11, for instance, the team will conduct a flight test of the new autonomy that will power off components prior to the solar eclipse, allow the battery to discharge by approximately the same amount as during the real eclipse, and then power on components again once the battery is recharged, all in a more controlled setting with real-time visibility. This test will be combined with a battery reconditioning.

Later in August and through September, during the approach to Venus, MESSENGER's navigation team will use the Mercury Dual Imaging System cameras onboard the spacecraft to take a series of optical navigation pictures. These images are not required for the Venus flyby but will be used by the MESSENGER navigation team for calibration and as practice for the optical navigation imaging to be utilized at Mercury.

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft launched on August 3, 2004, and after flybys of Earth, Venus and Mercury will start a yearlong study of its target planet in March 2011. Dr. Sean C. Solomon, of the Carnegie Institution of Washington, leads the mission as principal investigator. The Johns Hopkins University Applied Physics Laboratory  built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA.