NASA Atlantis Shuttle Takes Final Ride to Hubble Telescope

by Roy Mark

Over the course of five spacewalks, astronauts will install two new instruments, repair two inactive ones and perform the component replacements that will keep the telescope functioning at least into 2014. Atlantis’ crew is charged with replacing Hubble’s workhorse camera responsible for some of Hubble’s most spectacular images and its black-hole-hunting spectrograph.

Atlantis launched on her maiden space flight in 1985 with a classified payload for the Department of Defense. Over the next 24 years, Atlantis has carried more DOD payloads and pioneered the Shuttle-Mir missions, flying the first seven missions to dock with the Russian space station. This is Atlantis’ first trip to Hubble.

En route to Hubble, astronauts will be running through their routines for an unprecedented mission: performing on-orbit surgery on two ailing science instruments that reside inside the telescope. It’s a daunting challenge, as Hubble’s creators envisioned astronauts swapping out components, not performing delicate tasks during spacewalks.

When Atlantis is about 200 feet away from Hubble, Goddard Space Flight Center will command the telescope to execute a roll that brings it into position for grappling. Astronauts will use the shuttle’s robotic arm to capture Hubble and dock it in the shuttle’s cargo bay.

Astronauts will remove Hubble’s WFPC2 (Wide Field and Planetary Camera 2) to make room for WFC3. The camera’s range is much greater than that of the WFPC2. The camera will be able to see 90 times more objects than the current camera.

Hubble’s batteries store the energy that powers the telescope during the “nighttime” portion of its orbit, when the Earth blocks the Sun’s rays. Astronauts will replace all six of Hubble’s 125-pound batteries with new, more effective versions.

A spectrograph is an instrument that breaks light into its component colors, revealing information about the object emitting the light. COS sees exclusively in ultraviolet light and will improve Hubble’s ultraviolet sensitivity at least 10 times, and up to 70 times when observing extremely faint objects.

Hubble needs a new power supply circuit board, but the electronics access panel was never meant to be opened and is attached by 111 small screws. Engineers created a “fastener capture plate” that fits over the top of the panel and captures the screws in the plate.

Time has degraded Hubble’s gyroscopes to the point where three have failed, two are in use and a third is turned off to be used as an emergency backup. Astronauts will install six new gyroscopes in addition to new fine guidance sensors.

Using Atlantis’ robotic arm again to release the telescope, the Goddard Space Flight Center will issue the commands to bring the telescope back into operation. The first new images from the telescope will be released midyear.

As Atlantis travels home, the Goddard Space Flight Center will begin a several-month-long period of testing and calibrating the new on-board equipment. Restored and updated, Hubble will continue on its journey around the Earth, its new components merging—hopefully— with the old.

Atlantis Commander Scott Altman on repair trip to Hubble: “I think it’s a step that we need to take to make us better able to go to places like Mars. You don’t want to drag a whole spare giant box along … Being able to demonstrate this in space is a key element of us growing as a spacefaring people.”

As NASA seeks to fulfill the Vision for Space Exploration program, beginning with the completion of the International Space Station, Atlantis will be scheduled for heavy duty over the last year and the final nine missions remaining for the shuttle program.