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Mars lander preview

A preview of NASA's Phoenix Mars lander mission and the science objectives to dig into the arctic plains of the Red Planet are presented here.

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Phoenix animation

Project officials narrate animation of Phoenix's launch from Earth, arrival at Mars, touchdown using landing rockets and the craft's robot arm and science gear in action.

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Dawn launch delay

Jim Green, director of the Planetary Science Division at NASA Headquarters, explains why the agency decided to delay launch of the Dawn asteroid probe from July to September.

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Endeavour rolls to VAB

Shuttle Endeavour is transported from its hangar to the Vehicle Assembly Building for joining with a fuel tank and boosters for launch on STS-118.

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Welcome home, Atlantis

The Shuttle Carrier Aircraft touches down on Kennedy Space Center's Runway 15 on July 3, delivering Atlantis back to its homeport after a two-day coast-to-coast ferry flight.

 Landing | Tow

Atlantis heads home

Nine days after landing at Edwards Air Force Base to conclude the STS-117 mission, Atlantis begins its cross-country ferry flight back to Florida.

 Taxi | Takeoff

Dawn preview movie

Learn more about the upcoming Dawn mission that will use an ion engine propulsion system to visit two of the largest objects in the asteroid belt.

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DMSP satellite operated in first-ever gyroless control
AIR FORCE NEWS RELEASE
Posted: July 18, 2007

LOS ANGELES AIR FORCE BASE, El Segundo, Calif. -- Defense Meteorological Satellite Program Flight F15, launched in December 1999, successfully operated without navigation gyros for 24 hours demonstrating a new promising capability that can extend portions of the DMSP mission even when critical gyro data is not available.

In the gyroless navigation mode, the DMSP satellite uses its earth sensor and sun sensor along with an innovative software estimate of yaw error to maintain proper attitude.

This is the first DMSP satellite ever flown in a completely gyroless configuration.

"Though flight 15 is operating beyond its design life, it is currently running on a single remaining gyro." said Col Bradley Smith, Commander of the Defense Meteorological Systems Group.

"The DMSP team showed outstanding ingenuity by developing new satellite control modes that require less than two gyros normally needed for attitude control to mitigate loss of mission: First with a single gyro control mode back in 2002, and now with this gyroless mode. We are very pleased with the success of this on-orbit demonstration, since this shows DMSP can continue to support a portion of our mission even when all gyros have failed."

F15 has been a secondary DMSP asset since Nov 2003 and has operated on a single remaining gyro for an extended period. In addition, F15 carries a radar calibration sensor that is a vital primary asset for the radar community worldwide including our DoD users. By demonstrating stable gyroless control of the satellite, the radar calibration mission may be extended once the last remaining gyro fails. In addition the spacecraft's secondary space environmental monitoring mission may also be extended.

The Space and Missile Systems Center, located at Los Angeles Air Force Base, Calif., is the U.S. Air Force's center of acquisition excellence for acquiring and developing military space systems including six wings and three groups responsible for GPS, military satellite communications, defense meteorological satellites, space launch and range systems, satellite control network, space based infrared systems, intercontinental ballistic missile systems and space situational awareness capabilities. SMC manages more than $60 billion in contracts, executes annual budgets of $10 billion and employs more than 6,800 people worldwide.