The Japanese space agency JAXA has confirmed that its Hayabusa 2 space probe has left asteroid Ryugu, reached on June 27, 2018. Until November 19 it will keep on taking pictures of Ryugu, a limit due to the fact that subsequently a maneuver needed to use its ion engine will lead it to turn into a position from which it will no longer have the asteroid in its camera’s view. Until that day, it will be possible to send a farewell message to Ryugu via Twitter or even letters and postcards to JAXA. Hayabusa 2 is scheduled to return near the Earth with its samples near the end of 2020.
The so-called scientific phase of the Hayabusa 2 mission made it possible to collect soil samples from the Ryugu asteroid thanks to the descent carried out on February 22, 2019 and subsoil samples thanks to the descent carried out on July 11, 2019. In the second case Hayabusa 2 exploited a crater it generated on April 5, 2019. These descents were the most exciting events of the mission because they were the riskiest for a space probe that was working autonomously in conditions that could be of poor visibility due to dust. In the event of problems, the distance would have allowed them to be discovered at the mission control center too late to fix them.
The samplings in the two descents were successful and the samples were sealed in separate containers in the sample-return capsule (SRC). The return journey for the Hayabusa 2 space probe seems simple, as does the capsule’s landing, compared to the many maneuvers carried out in the vicinity of asteroid Ryugu but everything on board must keep on working.
The Hayabusa 2 space probe’s ion engine uses xenon as a propellant and after its Earth’s flyby to release the sample-return capsule it might still have enough for a second mission with a flyby to another object, which could be another asteroid. At JAXA they’re assessing the various possibilities but a lot will depend on the actual amount of xenon available.
For the occasion, JAXA has opened a campaign for the farewell to asteroid Ryugu that will last until November 19, asking the public to send messages via Twitter using the hashtag #SAYONARA_Ryugu or letters and postcards to the JAXA’s Hayabusa 2 project address, impractical for fans too far away but if you live close enough you can send them to: JAXA Institute of Space & Astronautical Science (ISAS), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara City, Kanagawa Prefecture, 252-5210, Japan. It’s the celebration of a mission that is going beyond the limits of what was accomplished so far by a space probe.