“The notion of transwarp beaming is like trying to hit a bullet with a smaller bullet, whilst wearing a blindfold, riding a horse” – Montgomery Scott (Star Trek)

JAXA’s post of a picture taken by MINERVA – 11A

This is the quote that comes to mind when thinking about the feasibility of this event.  In June 2018, a Japanese space probe called the Hayabusa2 finally intercepted the asteroid Ryugu.

Ryugu is a near-Earth object (NEO) that can come as close as 95,000 kilometers from the Earth.  NEOs are objects that are pushed by the gravitational effects of other bodies until they are very close to the Earth.  For reference about the proximity of Ryugu, the Moon is approximately 384,000 kilometers away from the Earth.  So if Ryugu is so close to Earth, it must be pretty straightforward getting there to study its composition, right?  Not quite, and the process of getting technology there is still an amazing feat of humankind.

Here is a bit of rough math to paint the picture of this scenario.  Ryugu orbits our Sun at an average distance of approximately 1.2 Astronomical Units (AU).  This is about 1.795e+11 meters.  For simplicity, if we assume Ryugu’s orbit is roughly circular, the circumference of its orbit is near 1.13e+12 meters.  Since Ryugu orbits the Sun once every 16 months, it travels at an average speed of about 27,000 meters per second!  To keep things in perspective, a rocket ship has to be travelling at 11,200 meters per second (7 miles per second) in order to break the Earth’s atmosphere.

MINERVA – 11 Rovers

The idea that we could launch a probe a distance of almost 100,000 kilometers, and have it intersect with an object travelling over twice the speed of a rocket is incredible.

Japan is the one to thank in this magnificent feat.  The Hayabusa2 is Japan’s second asteroid space probe.  The first probe was the Hayabusa, which successfully delivered samples of the asteroid Itokawa back to Earth in 2010.  The Hayabusa2 was launched in December of 2014, and did not meet with Ryugu until June of 2018.  Once in orbit of the asteroid, on September 21st, 2018, the space probe launched two rovers to land on the surface of the asteroid to record data, collect samples, and take pictures!

The two rovers sent to the surface are the MINERVA – 11A and the MINERVA – 11B.  These rovers are small, weighing only 2.4 pounds each.  According to officials from the Japan Aerospace Exploration Agency (JAXA), “Gravity on the surface of Ryugu is very weak, so a rover propelled by normal wheels or crawlers would float upwards as soon as it started to move”.  For this reason, Japan designed their rovers to hop.  Each time one of the rovers hops, it can leave the ground for up to 15 minutes, and can cover a distance of about 15 meters.

While only being on the surface for a few days, the MINERVA rovers have sent back numerous pictures, giving everyone back on Earth a fascinating view of the surface of Ryugu.  Looking towards the future, JAXA hopes to have these rovers collect samples of the asteroid, and return to Earth in late 2020.