500 million miles from Earth, in the dark outer reaches of the Solar System, a quiet alarm rings, waking a small spacecraft from its two-and-a-half-year slumber.
That small spacecraft is Rosetta. After nearly a decade of travel and more than 800 million kilometres logged, Rosetta woke earlier this week, ready to press ahead with its exploration of the comet 67P/Churyumov-Gerasimenko.
Rosetta runs on solar energy, so power fades with distance from the Sun. About 31 months earlier, the orbiter was far out in the Solar System near Jupiter and had to be put into a conserve-power slumber to stretch its energy reserves.
Over a decade in space, Rosetta had flown past Mars and Earth several times and even studied a few asteroids. Now it moves into the final leg of its mission, building toward a landmark encounter later this year.
In August it would reach the comet and begin to orbit. For about two months the spacecraft will map the comet’s surface in detail, looking for a landing site for its lander, Philae, pronounced Fee-lay. The landing on 11 November would mark the first comet landing ever attempted.
If this high-risk mission succeeds, it will yield a major scientific payoff. Comets act as time capsules from the early days of the Solar System. Studying them helps scientists understand how our corner of the universe first formed.
Cool Fact
Because of Rosetta’s distance from Earth, messages take up to 50 minutes to reach us. Cited: Space Scoop; based on ESA press materials.