"Herschel has a fixed end-date because its three instruments all need to be cooled to very low temperatures" says Cardiff University's Prof Matt Griffin, one of the team working on the mission.
"That cooling is provided by a big tank of liquid helium on board. The helium is gradually boiling away, and as planned, it will eventually run out and the instruments will stop working".
One proposal is to send the craft into a controlled collision with the Moon at the end of its life. It's hoped the impact might reveal more about ice hidden below the lunar surface.
"Some people don't like the idea because they think the Moon should not be contaminated by crashing a spacecraft into it, some other people think Herschel is such a lovely spacecraft that shouldn't be destroyed by crashing into a rock like the Moon!"
"But most of the members of my team are very much in favour. We don't regard the spacecraft as the final legacy... we regard the data and the science [as the legacy]. If we can do a little bit more at the end, we'd find that very pleasing."
The Herschel telescope is due to make its 50,000th successful observation today. Scientists at Cardiff University have helped to design the telescope.
A number of members of the School of Physics and Astronomy are also involved in the analysis and interpretation of the data sent back from Herschel.
Herschel is the largest astronomical telescope ever launched. It also has the largest mirror ever made, a 3.5 m-diameter primary mirror, which is giving astronomers their best ever view of the Universe at far-infrared and submillimetre wavelengths.
Scientists hope the telescope, which launched in 2009, will give a greater understanding of the origins of the solar system. It is orbiting a point in space 1.5million km from Earth and is coming to the end of its life.
Matt Griffin, from Cardiff University, says the telescope's likely to end it's journey in March next year. After that it will either need to be parked safely in orbit so as not to come into contact with the earth, or another option is to crash it into the moon in a controlled way.
If it's crashed into the moon then the impact can be observed by another satellite, and by earth, and further discoveries could be made.