The Hubble Space Telescope needs repair work just like every other large piece of equipment. But servicing an orbital telescope 350 miles above the Earth is no simple task. Here's a closeup look at how it's done.

We'll look at the 2002 repairs to the scope, known as Servicing Mission 3B. This was a mission to update and upgrade a number of Hubble's systems, as well as add new solar panels and an advanced camera that vastly increased the telescope's abilities. The key to making it all work was a replacement Power Control Unit, which disperses the power collected by the solar panels to Hubble's various systems.

The replacement procedure was a seven-hour job, with work progressing through both light and dark periods as Hubble orbited the Earth. Pictured is a DCU training unit, which the astronauts practiced extensively on before their mission so they'd know exactly what to do once they were floating in space.


The get the job done, astronauts disconnected 36 wire bundles, then pulled out the large electronic control box and installed a new one, reconnecting all the wire bundles. That would be a long, difficult job for any electrician, but imagine doing it with a spacesuit on.

Visible in the images are the large handles for the astronauts to hold onto, and the blue, white and red retainer loops. These allowed the wire bundles to be held in place, and more importantly held them in the correct order so everything could be reconnected properly.


Repair and service missions like this one, extended Hubble's distinguished career well beyond the original planned lifespan – it's been responsible for several landmark discoveries and has resulted in the publication of over 6,000 scientific papers.

This training unit resides at the Smithsonian Institution's National Air and Space Museum in Washington, D.C. It's part of a preview for a new exhibit on space exploration that will open in 2011. Below, you can see the Hubble after its 2002 repairs, floating in orbit.