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STS-124: In review

The STS-124 crew narrates highlights from its mission that delivered Japan's Kibo lab module to the station.

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Jason 2 launch

A ULA Delta 2 rocket launched the Jason 2 oceanography satellite from Vandenberg Air Force Base on June 20.

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Jason 2 preview

The joint American and European satellite project called Jason 2 will monitor global seal levels.

 Mission | Science

STS-124 space shuttle mission coverage

Extensive video collection covering shuttle Discovery's mission to deliver the Japanese Kibo science lab to the station is available in the archives.

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Phoenix lands on Mars

The Phoenix spacecraft arrived at Mars on May 25, safely landing on the northern plains to examine the soil and water ice.

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STS-82: In review

The second servicing of the Hubble Space Telescope was accomplished in Feb. 1997 when the shuttle astronauts replaced a pair of instruments and other internal equipment on the observatory.

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European orbiter begins closing in on Venus
EUROPEAN SPACE AGENCY NEWS RELEASE
Posted: July 21, 2008

Starting last week, spacecraft controllers have been executing a series of manoeuvres to gradually bring Venus Express closer to its host planet. In its modified orbit, the spacecraft will be able to observe unexplored regions and investigate phenomena that were not within its reach before.


Artist's impression of Venus Express. Credit: ESA
 
The operational manoeuvres to bring the spacecraft closer will be executed through the month of July, settling it into its new orbit by 4 August.

Until now, Venus Express has occupied a highly eccentric polar orbit: at its closest point (pericentre), the spacecraft is between 250 km and 400 km from the planet, and at its farthest (apocentre), it is about 66 000 km away. The pericentre is located at 84 north.

This eccentric orbit was designed to facilitate observation of the southern hemisphere for extended periods, and of the northern hemisphere and the northern polar region at closer distances.

The altitude of the pericentre will now be lowered to between 185 and 300 km. This modification will enable the following science advantages:

  • Study of the magnetic field in the northern polar region
  • Study of the plasma environment deeper in the ionosphere
  • To indirectly deduce the density of the planet's atmosphere by measuring the force, or drag, exerted by the planet's atmosphere on the body of the spacecraft as it moves closer to the planet

The lowering of the Venus Express orbit is the first step in a more ambitious strategy, yet to be confirmed in its entirety. The intention is to lower the spacecraft's orbit further into the atmosphere, such that the drag on the spacecraft's body can be measured by the on-board accelerometers.

As the next step, Venus Express may test aerobraking, a technique where a spacecraft uses the force exerted by the planet's atmosphere to decelerate and so significantly change its orbit in a controlled manner.