The most important telescope ever built, the Hubble Space Telescope, is to be abandoned.

Its striking and clear images of our universe result from the telescope’s location above the Earth’s atmosphere which otherwise serves to distort images before they reach any ground-based telescope.

The images Hubble has relayed back to Earth have determined the age of the Universe, discovered a mysterious energy which is causing all of the objects in the cosmos to accelerate away from each other and most recently, produced an image of the deepest view into deep space.

This image has detected the youngest and most distant galaxies ever seen, which scientists believe will lead to a major advance in our understanding of the cosmos.

Safety fears

The decision to end the life of this remarkable telescope was made by Nasa’s chief, Sean O’Keefe, as a direct result of the loss of the space shuttle Columbia in February last year, in which seven astronauts lost their lives.

The disaster led to new safety regimes introduced for shuttle flights ruling out any further missions to service Hubble.

Hubble requires service missions every few years to replace worn-out parts, without which it would degrade and eventually stop working altogether.

The remaining shuttle flights will be used to complete the construction of the International Space Station (ISS) only.

Missions to the ISS are safer since shuttle crew have a lifeboat in space should any problems arise.

However, the Hubble Telescope is not in an orbit from which the crew could possibly reach the ISS, so service missions were deemed unfeasible.

“This is a sad day,” said Nasa’s chief scientist John Grunsfeld, but “the best thing for the space community”.

Heads up

Hubble’s end however, will be a complicated and expensive one.

Left alone, Hubble is expected to fall to Earth sometime in 2012 and it is big enough not to burn up completely. The main mirror and its titanium support ring will survive and reach the ground.

One estimate reveals a one in 700 chance of human casualties resulting from an uncontrolled Hubble re-entry.

Thankfully, scientists agree this risk is unacceptable and are working on plans to attach a $300m space tug that would launch on a Delta 2 rocket, grapple Hubble and guide the telescope into the Pacific Ocean.

However, this will have to be carried out by an automatic docking, instead of by the planned shuttle mission, which Nasa does not yet have the technology to carry out.

New hope

It is a sad end to an instrument which has enabled a remarkable insight and understanding of the universe in which we live.

Nasa is now planning to put a new telescope into orbit in 2012.

The James Webb Telescope is an infrared telescope, where Hubble is primarily a visible light telescope.

While the new telescope would not be a replacement for Hubble, it will serve a new science mission.