The Hubble Space Telescope was deliberately designed to allow upgrades via servicing missions while the telescope remains in orbit. The plan was for shuttle missions to carry upgrades, new equipment and tools for repair and dock near the telescope, near enough that astronauts can repair and upgrade the telescope while it remains in orbit. This has worked extremely well. The current repair and upgrade cycle hit a glitch in October, but the next mission, Servicing Mission 4 (SM4), should be the last in the current upgrade cycle.

This time the shuttle will carry astronauts.When the shuttle is about 200 feet from Hubble, Goddard Space Flight Center in Maryland will command the Hubble telescope to execute a roll and turn that will position it so that astronauts can use the shuttle's robotic arm to grapple Hubble and bring it in to dock in the shuttle's cargo bay. Next, in a series of five spacewalks, each lasting several hours., astronauts in teams of two will install two new instruments, repair two non functioning instruments, and replace other components. These upgrades and repairs should keep the telescope functioning into 2014.

Of the various upgrades to be installed, the one I'm most excited about is the
Wide Field Camera 3. WFC3 sees three different kinds of light: near-ultraviolet, visible and near-infrared, though each "shot" needs to be planned ahead of time since each spectrum requires different commands. The new camera's range and sensitivity are much greater than the current camera, with a larger field of view and better resolution.

In addition, astronauts will swap out COSTAR, the Corrective Optics Space Telescope Axial Replacement installed during the very first repair mission to correct for flaws in Hubble's mirror, for the Cosmic Origins Spectrograph (COS). COS sees in ultraviolet light and will improve Hubble's ultraviolet sensitivity at least 10 times, and up to 70 times when observing extremely faint object.

And all six of Hubble's batteries, at 125 lbs each, will be replaced with upgraded, more efficient versions. In addition, the outside of Hubble will be covered in new, improved insulating blankets.

In the meantime, the image above is a shot from Hubble's recently repaired Wide Field Planetary Camera 2 (WFPC2, the one that's about to be upgraded in early 2009), showing a pair of gravitationally interacting galaxies called Arp 147. As the Hubble site explains:

The two galaxies happen to be oriented so that they appear to mark the number 10. The left-most galaxy, or the "one" in this image, is relatively undisturbed apart from a smooth ring of starlight. It appears nearly on edge to our line of sight. The right- most galaxy, resembling a "zero," exhibits a clumpy, blue ring of intense star formation.

The blue ring was likely formed after the galaxy on the left passed through the galaxy on the right, with the gravitational forces that resulted creating a ring of higher density at the point of impact. As this dense material collided with outer material inward from the gravitational pull of the two galaxies, the resulting shocks and dense gas that were produced, spawned star formation.

If you look at the lower left of the blue ring you can see a dusty reddish knot that probably marks the site of the original nucleus of the galaxy that was hit. in the initial collision. As you look at that stunning image (click it to see the larger original) keep in mind that that was taken with the old camera. Just imagine what we'll see next year!