STS-125: SM4 Servicing Mission to HST

The Final Visit to the Hubble Space Telescope

Please publish on May 8 (Friday)


Next week's launch of the Space Shuttle from the Kennedy Space Center will carry astronauts to the Hubble Space Telescope for their final visit.  This mission was previously cancelled when the Shuttle Columbia was lost in 2002.  Careful preparations has allowed NASA to resume this mission.  One of these measures is to have a rescue Shuttle on standby on the other launch pad, and it has led to the rare sight of two Shuttles on the two launch pads. 

Due to the delay, there has been ample time to prepare for this mission.  The entire team, from the astronauts, to the people that build the hardware are ready.  One of these is Edward Cheung, who was born and raised in San Nicolas.  Edward has been working on the Hubble Project since 1996, and this marks his fifth Hubble mission.  On this mission, he has had many roles, including Electrical Lead on Wide Field Camera III (WFC3).  This new imaging camera will improve Hubble's discovery factor by ten times, and will offer up unbelievable new images of our Universe. 

The original date for this mission was in October 2008.  Only two weeks before launch, Hubble experienced a critical failure of its Science Data Handling Computer.  This caused the project to switch to the backup unit.  Although the prime unit has operated for 18 years, NASA decided that it was not prudent to have Hubble fly the remaining years without a backup.  It was decided to refurbish a spare unit that was on the ground, and delay the mission so that it could be included.  Edward was given the responsibility to lead the electrical effort to bring this new unit on line.

Along with these major items, Edward also worked on two smaller parts of the mission.  These were the repair of the Advanced Camera for Survey, and the Telemetry Module.  His role after launch will be at the Johnson Space Center in one of the Flight Control Rooms.  The team that built the hardware will be on hand to help with the installation, and any problems that may occur during the checkout phase.

At the launch, Edward will be joined by his wife and kids, and also Mr. Jan Poets is expected to be there with his camera crew.  Edward welcomes questions about this mission, especially from school-aged children from Aruba.  Please write to him at

Launch is scheduled for 2pm on May 11, 2009

Possible images for this story
(full resolution version available for most of these)
Building WFC3
Where WFC3 will be installed
Testing the Science Data Computer
Astronaut training
With the flag on the pad
Shuttle pad at night with Canister lift
At the launch pad with Atlantis
In the commander's chair
With a space suit helmet

Links to hardware that Edward built for this mission
Wide Field Camera III
Science Data Computer
Telemetry Module

Links to Edward's mission update pages
Page 1
Page 2
Page 3
Page 4
Page 5

Other Past Missions

NASA's official site for this mission.  Lots of great multimedia resources.

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(c) 2009, Edward Cheung, all rights reserved.