JAXA proposes possible Hayabusa 2 landing sites on asteroid Ryugu

Asteroid's terrain and structure make site selection more difficult than anticipated.
By Laurel Kornfeld | Jan 18, 2019
The Japan Aerospace Exploration Agency (JAXA) has selected possible landing sites for its Hayabusa 2 probe on the asteroid Ryugu, from which it will gather samples that will be returned to Earth for analysis.

Selection of the sites required modeling and analyzing the shape of the 9,843-foot- (3,000-meter-) wide asteroid, identifying temperatures at various locations, and determining the density of boulders on its surface.

"We learned that that asteroid is not friendly to us, so [landing is] not as easy as we had supposed when we were planning the mission," said Masaki Fujimoto, director of solar system exploration at JAXA's Institute of Space and Astronautical Science.

During a day-long conference last week, JAXA officials announced a site designated L08 as its ideal landing location, with backup sites designated as L07 and M04. Additional, separate landing sites were given for Hayabusa 2's MASCOT suite of science instruments and MINERVA-II-1, which holds two rovers that will be placed on Ryugu's surface.

MASCOT carries an infrared spectrometer, a magnetometer, a radiometer, and a camera. The latter will image the distribution, structure, and texture of surface material.

All of the selected sites are flat regions located within 656 feet (200 meters) of the asteroid's equator, have slopes less than 30 degrees, have flat regions with 328-foot (100-meter) diameters, contain boulders no higher than 20 inches (50 cm), and have temperatures below 206 degrees Fahrenheit (97 degrees Celsius).

These conditions are considered ideal for the size of Hayabusa 2's sample device, its best operating temperature, and the direction of its solar panels.

Touchdown rehearsals for the 1,300-pound probe will be conducted on September 12 and in mid-October. Actual landing is currently planned for late October.

MINERVA-II-1 is scheduled to begin operations on September 20-21, followed by MASCOT on October 2-4.

After landing, the spacecraft will drill into Ryugu's surface and collect subsurface samples in a capsule.

Studying Ryugu is valuable because the asteroid contains both water and the organic molecules that made up the building blocks of Earth.

Samples collected will be returned to Earth in late 2020.


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