Hubble Missions!

Galaxies from the early universe. The birthplaces of planets. Dark matter. Dark energy. Since its launch in 1990, the Hubble Space Telescope has brought these mysteries into focus, its powerful gaze scanning the universe for the details planet-bound telescopes find impossible to detect.

Far above the Earth's surface, Hubble floats clear of the planet's light-distorting atmosphere, beaming back images that have transfixed humanity and changed the scientific world.

Hubble's triumphs continue to accumulate thanks to a unique design that allows astronauts to repair and upgrade the telescope while it remains in orbit. Repairs keep the telescope functioning smoothly, while upgrades to the instruments bring a slew of new discoveries and science.

On October 10, 2008, astronauts will board the Space Shuttle Atlantis for Servicing Mission 4 (SM4), the final trip to the Hubble Telescope. Over the course of five spacewalks, they will install two new instruments, repair two inactive ones, and perform the component replacements that will keep the telescope functioning at least into 2014. The effort-intensive, rigorously researched, exhaustively tested mission also involves diverse groups of people on the ground throughout the country.

Ready, Set, Go

The mission's planning is years in the making, and its success will be the product of months of intensive preparation and the work of hundreds of people at NASA and in academia and industry.

Astronauts train at NASA's Johnson Space Center in Texas, where they learn to deal with weightlessness in a giant water tank in the Neutral Buoyancy Lab, and at Goddard Space Flight Center in Maryland, where they enter Goddard's huge intensively filtered "clean room" to work with the actual equipment they'll use and install aboard Hubble. Goddard prepares and tests instruments and hardware, while Kennedy Space Center in Florida prepares the space shuttle for the mission.

Read these behind-the-scenes stories leading up to the mission

During SM4, teams at Johnson and Goddard work around the clock to make sure the mission succeeds. Johnson's Mission Control Center monitors the space shuttle and astronauts, and supervises spacewalks, procedures, crew activities and health, as well as shuttle systems and experiments. Hubble personnel, including managers, scientists, and engineers from Goddard and the Space Telescope Science Institute in Maryland, will be split between supporting the mission at Johnson and those working at Goddard.

At Goddard, where the Hubble program is administered, the Space Telescope Operations Control Center controls the telescope itself, giving the commands that prepare the telescope for the astronauts' activities and test the newly installed equipment. Goddard's Control Center closes the door that protects the telescope's delicate optics, and maneuvers Hubble into position as the shuttle Atlantis approaches.

When the shuttle is about 200 feet (60 m) away from Hubble, Goddard will command the telescope to execute a roll that brings it into position for grappling. Astronauts use the shuttle's robotic arm to capture Hubble and dock it in the shuttle's cargo bay.

source : http://www.nasa.gov/#


Next, the astronauts begin their series of five six-and-a-half-hour spacewalks. Two astronauts work outside on Hubble at a time. One mainly handles the free-floating tasks. The other is connected by a foot restraint to the robotic arm, which is operated by a third astronaut from within the shuttle. To keep themselves from accidentally floating away, the astronauts attach safety tethers to a cable that runs along the cargo bay. Hubble was built with handrails that also make it easy for astronauts to cling to the telescope.