One of the most powerful pieces of space equipment ever launched has lost its ability to collect data. As was always inevitable, the Herschel Space Observatory has run out of the helium needed to cool instruments.
The observatory, built and run by the European Space Agency, was launched in 2009. It used a 3.5 meter mirror to collect data and specialized in collecting light in the far-infrared and sub-millimeter frequencies — those between light visible to the human eye and microwaves.
This allowed it to pick up images of particularly cold parts of the universe and detect dusty areas where stars were still in the process of being created (at least at the point in the past that the images showed.)
Some more familiar territory was also captured by Herchel. The image above, courtesy of the ESA, shows layers of gas emitted by Betelgeuse.
To operate properly, the equipment had to be cooled to minus 456 degrees Farenheit, just a few degrees above absolute zero. It did this with 2,300 liters of liquid helium which has now run out. The instruments have now warmed and can no longer pick up infrared light accurately.
The cooling system worked somewhat like a Thermos flask, meaning it didn’t require any mechanical operations. Such an approach would have extended the maximum operation time but would have been risky as a single mechanical fault could have ended the entire project. That was too much of a gamble for a project that cost around a billion Euros (US$1.3 billion).
Herschel actually lasted longer than expected, allowing it to record 25,000 hours’ worth of data, compared with the 20,000 that was expected. Professor Matt Griffin told the BBC it could be another five years before staff have fully analyzed the results.
The discoveries that have already been made thanks to Herschel include the possibility that comet strikes are the source of water on Earth, and that gas shooting out of newly-formed stars could “puncture” the surrounding atmosphere and effectively create a hole in space.
Herschel has been operating at the L2 point, a location that balances the gravitational pull of Earth and the Sun, meaning it orbits in a constant position relative to Earth, in turn meaning it doesn’t suffer temperature swings because of falling into the Earth’s shadow. Staff will now direct Herschel to a slower orbit around the Sun.