Hayabusa-2 completes rehearsal for MINERVA-II drop

Hayabusa-2 has successfully completed its rehearsal for its planned drop of its last MINERVA-II bouncer/rover, releasing two reflective targets in order to track how they spiral down to the surface of Ryugu.

Hayabusa 2’s cameras will track the movement of the two navigation aids as they fly in space around Ryugu over the next several days. Scientists expect Ryugu’s tenuous gravity will pull the target markers to the asteroid’s surface within a week.

The release of that last bouncer is now expected in about a month. After spending time obtaining the data from that drop, Hayabusa-2 will then head back to Earth by the end of the year.

Hayabusa-2 dropping orbiting target marker

In preparation for the release and landing of Hayabusa-2’s second MINERVA-II2 tiny rover/bouncer, the spacecraft today began a close-approach to the asteroid Ryugu, where it will release two target markers.

Once released, Hayabusa-2 will back off to observe these markers as they spiral down into Ryugu, landing sometime around September 23.

This operation is a rehearsal for the release and landing of MINERVA-II2, which like the first two bouncers back in September 2018 will bounce along the asteroid’s surface, taking pictures and gathering data.

Deployment operations for Hayabusa-2’s MASCOT lander have begun

Engineers have begun the deployment sequence for Hayabusa-2’s MASCOT lander, with deployment planned for tomorrow.

Right now Hayabusa-2 is slowly moving closer to Ryugu, with live images appearing about once every half hour. More information about MASCOT can be found here. The lander can also hop like the MINERVA bouncers, but it can only do it once. Its battery life is about sixteen hours, so once it is deployed it will only operate on the surface for a short while.

Both the MINERVA and MASCOT mini-landers are mostly engineering tests for using small cubesat-sized spacecraft as probes. So far the MINERVA bouncers have been an unqualified success. Hopefully MASCOT will be as successfully.

New images from Hayabusa-2’s mini-bouncers

Three press releases from the Hayabusa-2 science team last night provide new images from the spacecraft’s MINERVA bouncers, presently on the surface of Ryugu, as well as new high resolution images from Hayabusa-2 during its recent close-in maneuvers.

The images from the first story also includes a ten second movie showing a very rocky surface with the sun moving across the sky. The last link shows the primary landing site candidate with two backup sites.

All told, these images suggest that Ryugu is nothing more than a rubble pile stuck together. If it was heading to Earth, it might be difficult to deflect it, as it might break apart caused by any stress.

Minerva probes send back first pictures

Ryugu's surface

Super cool images! The two Minerva probes released two days ago from Hayabusa-2 have both sent back spectacular images from the surface of Ryugu.

The image on the right was captured by the rover dubbed 1A. I have rotated it to show the surface on the bottom, but the actual picture was taking during one of the rover’s bounces while it was moving, so the returned picture had the surface on left. The white brightness is from sunlight. From the press release:

We have confirmed both rovers landed on the surface of asteroid Ryugu. The two rovers are in good condition and are transmitting images and data. Analysis of this information confirmed that at least one of the rovers is moving on the asteroid surface.

MINERVA-II1 is the world’s first rover (mobile exploration robot) to land on the surface of an asteroid. This is also the first time for autonomous movement and picture capture on an asteroid surface. MINERVA-II1 is therefore “the world’s first man-made object to explore movement on an asteroid surface”. We are also delighted that the two rovers both achieved this operation at the same time.

Other released images were taken just after release. One shows a blurred picture of Hayabusa-2, while the other sees Ryugu’s surface below.

Both of these rovers are designed to travel on the surface by a series of hops, taking advantage of Ryugu’s tiny gravity. There will be more images I’m sure from them in the coming days.

Hayabusa-2 science team lay out Ryugu landing schedule

At a press conference yesterday the Hayabusa-2 science team laid out their landing schedule for the spacecraft and its three tiny landers.

The first lander will be one of its two tiny MINERVA-II probes, and will take place in September. This will be followed by the German/French MASCOT probe in early October, followed in turn in late October by Hayabusa-2 itself.

The landings of the first two probes will help them pick Hayabusa-2’s landing site, as well as the site for last MINERVA lander.

Mission planners faced tough choices because the body almost uniformly strewn with boulders. “Ryugu is beautiful, but challenging,” said Aurélie Moussi, a collaborator from the French space agency CNES in Toulouse, at a press conference in Sagamihara, Japan, on 23 August.

…To minimize risks for MASCOT, mission planners mapped the topography of Ryugu and the distribution and size of the boulders on its surface. They ran computer simulations to produce a shortlist of ten options, and then picked one spot on the asteroid’s southern hemisphere. The choice reflected a number of criteria, including average temperatures on the ground and the materials that MASCOT will analyse with its four on-board instruments. “The other sites would have been just as good, or just as difficult,” says MASCOT payload manager Stephan Ulamec of the German Aerospace Center in Cologne. “Wherever we look, there is a lot of big boulders.”

It does appear that the boulder-strewn surface is posing a problem for the engineers.