Hayabusa2 Delivers Samples from Ryugu

Hayabusa2 Delivers Samples from Ryugu

Success for the Japanese Hayabusa2 Mission The capsule containing samples from the Ryugu asteroid landed safely near Woomera in Australia on 6 December 2020. The samples will be analysed in laboratories.

Six years and three days after taking off from Japan (on 13 December 2014), the Hayabusa2 Mission fulfilled its part of the bargain hands down, bringing us back samples from the Ryugu asteroid. However, the expected delivery did not take place in the Japanese archipelago, but much further south, in Australia.

DIRECTION AUSTRALIA AT 43,190 KM/H

The Hayabusa2 probe had reached the Ryugu asteroid, which is almost 1 km wide, in late June 2018. After a period of reconnaissance, it sent several small landers to the surface of this celestial body, including the Franco-German MASCOT on 3 October 2018. Then, on 21 February 2019, the “Peregrine Falcon” (Hayabusa in Japanese) took its first samples from the surface of Ryugu. The method used? Shooting a five-gram metal ball which, on impact, releases fragments from the surface so that some could be captured by a trunk-shaped device. The images are quite spectacular, as the video below shows.

The following April, Hayabusa2 launched an impactor and created an artificial crater to which it returned on 11 July to proceed with a new “catch,” this time at a greater depth. November 2019 was the month when the return journey started.

On 5 December, the probe was running on a planned collision course with our planet. As planned, 220,000 km from Earth it released a 40 cm diameter capsule of 16 kg, containing the samples “stolen” from Ryugu, towards us.

Le centre de contrôle de la mission au Japon le jour du largage réussi de la capsule contenant les échantillons. Crédit : JAXA

The mission control centre in Japan on the day the capsule containing the samples was successfully released.
Credit: JAXA

After a journey of more than five billion kilometres from its take-off, Hayabusa2 then carried out a manoeuvre passing 200 km from us on 6 December while the capsule entered the atmosphere heading towards Australia at a speed of 43,190 km/h. The thermal shield withstood up to 3000°C, while the samples got no warmer than 80°C, so that they would not be affected.

100 MG FOR THE HISTORY OF THE SOLAR SYSTEM

From the ground, the Japanese space agency’s cameras captured this artificial “shooting star” caused by the fiery re-entry of the capsule to the atmosphere.

Les échantillons de Ryugu arrivent sur Terre. En rentrant dans l’atmosphère, la capsule d’Hayabusa2 imprime sa marque dans le ciel australien. Crédit : JAXA/Cité de l’espace

The Ryugu samples arrive on Earth. On re-entry to the atmosphere, the Hayabusa2 capsule makes its mark on the Australian sky.
Credit: JAXA/Cité de l’espace

As on the previous Hayabusa mission (the first of that name), JAXA chose the huge Woomera military area in Australia to receive the capsule with the samples. At an altitude of 10 km, the parachute, designed to reflect radar signals and facilitate its detection, was deployed. The Japanese agency reported that landing was at 4.17 a.m., local time. Only two hours later, the precious cargo was found and teams were on-site.

La capsule et son parachute photographiés depuis un hélicoptère le 6 décembre. Crédit : JAXA

The capsule and its parachute photographed from a helicopter on 6 December.
Credit: JAXA

The recovery procedure was intentionally cautious, seeking to avoid contaminating the samples. For example, the integrity of the container was checked to ensure that the samples from Ryugu were not contaminated by our planet’s atmosphere, which would distort future analysis.

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JAXA confirmed that the sample container was intact in a press release. Scientists will therefore soon be able to examine 100 mg (the expected harvest) from Ryugu. As asteroids are the “left-overs” from the formation of the planets more than 4 billion years ago, these samples can be seen as very much unaltered witnesses of that period. A real journey in time which should help us better understand the birth of the Earth. As part of co-operation on this mission, French scientists will take part in analysing the treasure brought back by Hayabusa2.

Placés en sécurité dans une mallette de transport, les échantillons ont ensuite quitté l’Australie pour rejoindre le Japon. La JAXA a officiellement remercié les autorités australiennes pour leur aide dans cette opération. Crédit : JAXA/Cité de l’espace

Safely placed in a transport case, the samples left Australia to be taken back to Japan. JAXA officially thanked the Australian authorities for their assistance in this operation.
Credit: JAXA/Cité de l’espace

As for the probe, it continues to navigate. Its controllers on the ground will programme it to fly over the 2011 CC21 asteroid in July 2026, then go into orbit around another asteroid, 1998 KY26 in July 2031. At only 30 m wide and rotating on itself every 10 minutes, this is a type of object which has never been visited by a space craft. This time it will be a one-way trip.