Mission: Hayabusa 2 Options

[Marcin600]

And another interesting article from the same workshop: "THE ROLE OF ELECTROSTATIC DUST LOFTING IN SHAPING THE SURFACE PROPERTIES OF ASTEROIDS"

and this : "PLANS OF HAYABUSA2’s ONC IMAGE ARCHIVING AND PUBLIC RELEASE"

and a nice picture from this article : "Nature of Roughness of Ryugu Revealed by Thermal Simulation of High Resolution Digital Elevation Model". S. Tanaka et al. Asteroid Science 2019 (LPI Contrib. No. 2189):

Attached thumbnail(s)

 

[Marcin600]

Hayabusa2 began returning to Earth on November 13, at 10.05 JST

From JAXA twitter: "...In the end I decided to leave Ryugu. Departure tomorrow (November 13) at 10:05 (JST). The RCS thruster (chemical engine) is to start moving away from Ryugu at a speed of 10 cm / s....After leaving the gravity zone of Ryugu, we will continue preparations for the return to Earth by conducting a trial start of the ion engine..."

Press material - pdf, only in Japanese

Press conference - here

Attached thumbnail(s)

 

[Marcin600]

Official JAXA material in English

Real time delivery of navigation Images from the asteroid departure and current informations on JAXA twitter

Attached thumbnail(s)

 

[Marcin600]

Interesting conclusions from new article in Icarus magazine - Naoyuki Hirata et al. The spatial distribution of impact craters on Ryugu. Icarus, 5 November 2019, 113527:

"...It seems that the variation in crater density indicates that the equatorial ridge located in the western hemisphere is relatively young, while that located in the eastern hemisphere is a fossil structure formed during the short rotational period in the distant past..."

Image from the cited article:

Attached thumbnail(s)

 

[Marcin600]

Final pictures of Ryugu taken by Hayabusa2

[Marcin600]

According to statement of Prof. Noriyuki Namiki, head of the Hayabusa2 LIDAR research team, in the article "Sayonara, Ryugu" from November 21, 2019, posted on this site:

"...Hayabusa2 is currently considering a plan to send the sample back to earth and use the remaining fuel to transfer to a new exploration site."

[my unauthorized translation]

[tanjent]

I can only imagine what that means. If JAXA are considering placing the sample container on a ballistic trajectory from the present location to its eventual landing site in Australia with no further capability to do mid-course correction, that would really require pinpoint control. By contrast I recall that Hayabusa I performed tweaks until quite close to the day of its re-entry. That mission famously snatched success from the jaws of failure; it would be a shame if this one did the opposite.

Anyway, what resources (besides xenon) remain unexpended on the main vehicle, available for use in an extended mission?

[nprev]

"A new exploration site" would almost certainly mean a different asteroid or an inner-system comet. The return capsule cannot just be jettisoned away from the main spacecraft and make its way back to Earth. I would guess what is meant is that unlike Hayabusa 1, H2 may not reenter along with its capsule and burn up but instead maneuver after capsule ejection to do a close Earth flyby and retarget elsewhere for an extended mission.

They'd have to use the ACS to do that, of course, since the ion engines can't generate nearly enough thrust to accomplish such a maneuver during the short duration of an Earth flyby so possibly they may have used significantly less ACS propellant than they planned.

[Paolo]

I posted on the subject some time ago

http://www.unmannedspaceflight.com/index.p...st&p=239674

[Marcin600]

Also in this article are some details (September 2017):
"...The asteroid 2001 WR1 is identified as the most promising target candidate...for a flyby on June 27, 2023..."
"...Upon its return, at the end of 2020, the spacecraft will release the capsule for Earth re-entry and drift away from the planet. Based on the current mission profile, the spacecraft is expected to retain 30 kg of xenon propellant for trajectory maneuvers after the capsule is released. This remaining fuel can be used to extend the mission..."