asteroid in space

Nasa’s asteroid mission prepares for journey to outer solar system

Image credit: Dreamstime

Nasa’s 'Lucy' asteroid mission, which is aimed at studying the Trojan asteroids that surround Jupiter, is due to launch on Saturday.

The $980m, 12-year mission will explore more asteroids than ever before. If all goes according to plan, the spacecraft will reach its first flyby (an asteroid in the main asteroid belt) in April 2025, followed by seven Trojan asteroids beginning in August 2027. Its path will circle back to Earth three times for gravity assists before landing, making it the first spacecraft to return to Earth from the outer solar system.

The Trojan asteroids orbit the Sun in two elongated swarms: one group ahead of Jupiter in its path, the other behind it. These two regions contain approximately as many asteroids as the main asteroid belt. Observations of these asteroids have led to the suggestion that they may be coated in certain organic polymers formed by solar radiation, and that they may have been captured into their orbits during the early stages of the solar system’s formation.

“Asteroids are thought to be the remnants of planetesimals: precursors of the planets in the early solar system, which coalesced under gravity to form the familiar worlds we know today,” explained Dr Gareth Dorrian of the University of Birmingham. “Asteroids somehow escaped this process, preserving something of the conditions of our early solar system, from a time before even the planets had formed.

“This epoch is quite mysterious. How tiny dust particles – which constituted the bulk of solid material at the time – were able to clump together and form larger objects like asteroids, given that they lack significant gravitational fields of their own, is still being investigated.”

It is hoped that Lucy’s observations will reveal hints about how Earth’s neighbours formed billions of years ago, and how they ended up in the configuration we see today. The hope that the mission will provide these insights into the origins of the planets and formation of the solar system led it to be named Lucy, after the famous fossil that provided valuable insight into human evolution.

The Lucy spacecraft is more than 14m tip to tip, with most of this length comprised of huge solar panels (each more than 7m in diameter), which will power it as it travels to the outer solar system. The cameras, spectrometers, and communications equipment are located on the much smaller spacecraft body.

The launch is planned for no earlier than 5:34am EDT (10:34am BST) on Saturday 16 October on a ULA Atlas V 401 rocket from Cape Canaveral, Florida. There are additional launch opportunities the following day, should weather or other issues prevent the planned launch.

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