For a real change of perspective, head over to the Japan Aerospace Exploration Agency (JAXA) website to see videos and photographs from the Hayabusa2 mission. The pictures are courtesy of two tiny robot rovers, Minerva-II1A and Minerva-II1B, that landed late last month on the asteroid Ryugu. In addition to being an astonishing technological feat, this mission should provide invaluable information about the origins of our solar system. The project and those results are an important reminder of the importance of space exploration and the ability of all countries to contribute to such endeavors.
Ryugu is a 920-meter-wide asteroid in orbit around sun between Earth and Mars, about 300 million kilometers from Earth. The Hayabusa2 mission was launched Dec. 3, 2014, and rendezvoused with Ryugu on June 27 this year. That was an extraordinary accomplishment. The craft is now moving with the asteroid at a speed of about 22 to 32 km per second (relative to the sun) as it continues its mission.
On Sept. 21, the mothership maneuvered itself to just 55 meters from Ryugu, where it dispatched the two rovers; it then returned to its usual position 20 km from the asteroid’s surface. Maneuvering a spacecraft with objects moving at speed from such a distance takes extraordinary calculations and a steady hand. Only twice before have spacecraft accomplished a soft landing on an asteroid: NASA’s Near Earth Asteroid Rendezvous-Shoemaker spacecraft landed on Eros in 2001, and the original Hayabusa mission put a probe on Itokawa in 2005. Minerva-II1A and Minerva-II1B — the name stands for “Micro Nano Experimental Robot Vehicle for Asteroid — are tiny: (18 by 7 centimeters) yet they are loaded with scientific sensors and seven cameras apiece.
Because the asteroid’s surface is pitted and uneven, the probes have no wheels. Instead, they “hop,” jumping upward and remaining afloat for up to 15 minutes because Ryugu’s gravity is so weak. Each “jump” can travel as far as 15 meters. The plan is for both probes to jump all over the asteroid to map its surface. Both before, during and after jumps, the Minerva probes have been sending back pictures and videos, veritable postcards from hundreds of millions of kilometers away.
This week, JAXA will deploy a third rover, named Mobile Asteroid Surface Scout (Mascot), a joint German and French probe that will use an infrared microscope and wide-angle camera to take its surface measurements. Unlike the Minerva probes, Mascot is bigger — it weighs 10 kg — and will jump only once.
Next year, another hopping robot, Minerva-II2, will land on Ryugu. Then, sometime afterward, the Hayabusa2 mothership will again descend, this time all the way to the asteroid’s surface, to collect soil samples. The ship will create a crater and then extract at least 1 gram of material that has not been exposed to the elements for analysis back on Earth. If all goes according to plan, that subsurface material will return in a special capsule, parachuting into Australia in December 2020.
Examination of that dirt could give scientists vital details about the origins of the cosmos. While these smaller space bodies were thought to have been created at the same time as the rest of the solar system, they have not been exposed to the elements as have larger planets and thus remain largely unchanged since their formation. Scientists will be able to explore their hypothesis that such asteroids played key roles in the spread of organic materials and water around the solar system — helping us better understand the origins of life itself. The photos that the Minerva probes are sending provide additional insight into conditions on the surface and conditions in space. Other sensors record heat, magnetic properties and its composition.
Hayabusa2 is a reminder that vital space missions do not have to be manned flights or multibillion dollar programs. With a price tag of less than ¥30 billion, the Hayabusa2 project is a bargain. Such programs are not as sexy, as expensive or as dangerous as manned space programs, but they can provide equally valuable information. They can be launched quicker, more frequently and with considerably less expense. Japan should continue to invest in such efforts, playing to its strengths in robotics and nano- and micro-technologies. The Minerva landings and the images that they have mustered also help generate public support for Japan’s civilian space programs, an important balance to the increasingly military focus of discussions of outer space. We look forward to more postcards from distant reaches of our solar system.
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