Ryugu asteroid or comet?

Another spacecraft will land on an asteroid or comet surface and this time hopefully bring back sub surface material from explosive mining.

Are they mostly just different classes of the same object based on their rock compositions and orbits? Will asteroids and comets have similar surface material? Is asteroid Ryugu the same as any comet we have visited or will it be similar to one we will journey to in the future?

The Japan mission team should certainly be surprised by what they do and do not find.

The craft is now about 215km away from Ryugu and should arrive on 27 June. Hayabusa’s camera is starting to resolve its shape, which has been likened to a Japanese dango dumpling.

But closer inspection shows that the object is pitted with dents or craters. In addition, the asteroid’s orbit is retrograde, meaning that it spins in the opposite direction to the Sun and the Earth…

The Japanese Aerospace Exploration Agency (Jaxa) spacecraft will then survey the object for a year-and-a-half, during which it will aim to deploy several landing craft on the surface and use an explosive device to dig out a “fresh” rocky sample from within Ryugu.

The mission will depart Ryugu in December 2019 with the intention of returning to Earth with the asteroid samples in 2020.
Dumpling-shaped space rock comes into view

Do asteroids become comets (active asteroids) only due to orbits or does their chemical elements composition have a significant impact on their electrochemical interaction with the solar systems plasma?

Ryugu is a so-called C-type asteroid, a kind that is thought to be relatively primitive. This means it may be rich in organic and hydrated minerals (those combined with water). Studying what Ryugu is made from could provide insights into the molecular mix that contributed to the origin of life on Earth.

The surface of the asteroid is likely to have been weathered – altered by aeons of exposure to the harsh environment of space. That’s why Hayabusa 2’s scientists want to dig down for as fresh a sample as possible.
Japan’s Hayabusa 2 spacecraft reaches cosmic ‘diamond’

Asteroid formation theories in a spin?

Dr Yoshikawa, who is an associate professor at Japan’s Institute of Space and Astronautical Science (ISAS), said Ryugu’s shape was unexpected.

He said asteroids with this general shape tended to be fast-rotating, completing one revolution every three or four hours. But Ryugu’s spin period is relatively long – about 7.5 hours.
Japan’s Hayabusa 2 spacecraft reaches cosmic ‘diamond’