Japanese spacecraft to search for clues of Earth’s first life
In a Physics World special report on Japan, Dennis Normile reports on how the Japanese space agency JAXA plans to land a spacecraft onto an asteroid in 2018 to search for clues of how life began on Earth.
Hayabusa 2 will be JAXA’s second attempt at collecting material from an asteroid, after its first mission returned to Earth in June 2010. Hayabusa 2 will be launched in 2014 with a view to settling on the targeted asteroid, named 1999 JU3, in mid-2018 before arriving back on Earth in 2020.
As soon as Hayabusa 2 safely reaches its destination it will fire fingertip-sized bullets into the surface of the asteroid at speeds of 300 m s–1 and collect the rebounded fragments. After moving to a safe distance away, it will then detonate an impactor module, which will fire a 2 kg projectile into the asteroid to create a 2–7 m crater.
Hayabusa 2 will then return to the crater to collect samples that, as Normile writes, will not have been exposed to space weather and solar radiation before and will therefore have been created in the very early days of the solar system.
It is thought that the asteroid’s distance from the Sun will mean a better environment for preserving water and amino acids, which may add weight to the theory that asteroids and comets helped bring life to Earth.
JAXA’s first mission, Hayabusa, overcame engine failures, fuel loss and communication blackouts to finally return to Earth after successfully landing on the asteroid Itokawa. Tens of thousands of people in Japan watched the spacecraft re-enter the Earth’s atmosphere via Internet streaming and more than 100,000 people queued at several venues around the country to catch a glimpse of the capsule when it went on display.
A malfunction during the original mission meant that bullets could not be fired to collect samples; however, specks of dust from the asteroid were caught in the collection canister, meaning some material was returned for analysis.
Shogo Tachibana, a cosmological chemist at Hokkaido University who is principal investigator for sampling for Hayabusa 2, hopes the material from the second mission will be free of contamination and therefore give a clearer insight into the early days of the solar system, unlike samples of meteorites that have crashed to Earth in the past.
This article is part of a special focus issue of Physics World that draws together a selection of Physics World’s recent articles about physics in Japan.