Spacecraft counts down to crash suicide mission

Craft will hit comet today

The countdown has started for the Rosetta spacecraft’s suicide mission as final preparations are made to crash it on to a comet.

Commands were being uploaded last night to line up the European Space Agency (ESA) orbiter for its one-way trip to the rugged surface of comet 67P/ Churyumov-Gerasimenko.

Rosetta was to carry out a “collision manoeuvre” at 9.50pm UK time at an altitude of about 19km (12 miles).

From that moment, there will be no turning back.

The spacecraft will head straight for the comet, hitting the ground at around 11.40am UK time today to bring a dramatic end to its £1 billion mission.

Confirmation of the spacecraft’s death is not expected until later because of the time it takes for radio signals from Rosetta to reach planet Earth.

Despite travelling at just 1.1mph – walking pace – the craft is not designed for landing and will not survive.

Rosetta will remain crumpled and lifeless on the surface of the comet as the object, a dirty chunk of ice and dust measuring 2.8 miles across, carries it on repeated circuits of the solar system that may continue for millions of years.

The decision to crash the spacecraft was taken because the comet is now heading so far from the Sun that soon its solar panels will not be able to generate enough power to keep it functioning.

Scientists are hoping to obtain stunning images and valuable data in the final moments before impact.

Speaking on an ESA YouTube hangout, Rosetta flight director Andrea Accomazzo said: “From an energy point of view it will be a soft landing.

“But Rosetta’s not designed to land, so there will be some energy dissipation. For sure, Rosetta will bounce or tumble on the surface of the comet, but will not bounce back into orbit.”

He added: “We could have abandoned the spacecraft... but this is not what we want to do.”

The big risk faced by scientists is that there will not be time for all the information they hope to obtain to be “downlinked” to Earth.

Rosetta reached comet 67P/Churyumov-Gerasimenko on August 6 2014, after a 10-year journey through the solar system.

Three months later, on November 12, the spacecraft deployed a tiny lander, called Philae, which bounced on to the comet surface before coming to rest in a dark crevice.

Today Rosetta will follow Philae down to the comet’s smaller lobe.