Mission: Hayabusa 2 Options

[Marcin600]

JAXA has released a new Hayabusa2 extended mission video (English version): here and here (540 MB)

[Explorer1]

Thanks for the link, I completely forgot that they still have one target marker and one "bullet" they can fire from the sample collector! If there is an extended period near the asteroid, there might even be a chance to test the gravity tractor theory of asteroid deflection. Could the mass of something so small, with virtually non-existent gravity, even be measured to any degree?

[Marcin600]

Thanks for the link, I completely forgot that they still have one target marker and one "bullet" they can fire from the sample collector! If there is an extended period near the asteroid, there might even be a chance to test the gravity tractor theory of asteroid deflection. Could the mass of something so small, with virtually non-existent gravity, even be measured to any degree?

I feel (but not sure) that Hayabusa2, due to its design for a completely different purpose, is not a suitable spacecraft for the "gravity tractor" experiment.
1. For example, it does not have sufficiently sensitive instruments (?).
2. The target asteroid (1998 KY26) is so small and distant that it is a great challenge to measure from Earth the possible extremely small effect of changing its orbit.
3. In addition, this experiment requires a really long operation of the ship's engines in the gravitational field of the asteroid. I don't know how much fuel (ionic and conventional) will remain in the Hayabusa2 tanks after many years of flight, correction maneuvers and the asteroid's "orbit insertion". But I'm afraid there will be too little for this experiment...

But seeing this strange object up close will be very interesting. If this is a "standard rubble pile", why has it not broken up into a cloud of debris by extremely fast rotation (and therefore strong centrifugal force) with minimal gravity? It must be something very interesting and different from the conventional models of internal structure of asteroids. Maybe it's just a huge boulder in space?!

As a curiosity, it can be added that if 1998 KY26 were a sphere, then for an astronaut with a height of 1.8 m, the horizon line would be at a distance of less than 7.5 m!
(according to the formula: horizon distance = square root of the sphere diameter times the height of the observer (all in meters); √D x h (in meters), where: D - sphere diameter in meters, h - observer's height in meters)

For Curiosity rover's Mastcam on the surface of 1998 KY26 the horizon would be only approx. 8 m from the rover! Pretty limited field of view

[Explorer1]

Yes, the tractor is probably implausible. I do wonder how 'station-keeping' works at something so small. Solar pressure is undoubtedly a major factor when compared with the asteroid's own gravity.

[Marcin600]

It will be more like the parallel flight of two spaceships than orbiting.

And the solar radiation pressure should be quite disturbing to the orbit of such a small asteroid itself (over a long period of time).

[With a diameter of 30 m, the mass of 1998 KY26 (depending on density: from 0.5 to 5 g/cm3) should be between 7,000 and 70,000 t (metric ton). That is between 17 and 170 times more than ISS and between 14,000 and 140,000 times more than Hayabusa2 (approximately, if I did not make a calculation error ]

[Marcin600]

"Information on observing the re-entry capsule" on the JAXA website (in English, pdf with the application)

[Marcin600]

Picture of Hayabusa2 taken by the Subaru Telescope on November 20, 2020 (point of light in the center of the image). The spacecraft was 5.8 million kilometers away.
From here.
© Subaru Telescope, NAOJ

Attached thumbnail(s)

 

[Marcin600]

5 days until arrival of Hayabusa2 - currently 1.9 mln km to Earth

New reporter briefing - November 30, 2020, in English - pdf:
- Results from TCM-3 (orbit control correction)
- Details of capsule separation and re-entry
- Preparation status for capsule collection


Timeline:

Capsule separation: December 5, 14:30 JST = December 5, 5:30 UTC (Earth distance 220,000 km)

Capsule atmospheric entry: December 6, 2:28~2:29 JST = December 5, 17:28~17:29 UTC (altitude 120 km)

Parachute deployment: December 6, 2:31~2:33 JST = December 5, 17:31~17:33 UTC (altitude 11~7 km)

Capsule landing: December 6, 2:47~2:57 JST = December 5, 17:47~17:57 UTC

[Marcin600]

Hayabusa2 capsule separation operation online relay:
12/5 (Sat) 13:30 ~ 16:40 (max. ext. 17:30) JST = December 5 (Sat), 4:30 ~ 7.30 UTC
Japanese:: https://www.youtube.com/watch?v=vRuXaH
Simultaneous English translation: https://www.youtube.com/watch?v=BiP1rGR6CRM

Hayabusa2 capsule Earth return online broadcast:
12/6 (Sun) 02:00 ~ 03:10 (max. ext. 03:30) JST = December 5 (Sat), 17:00 ~ 18:10 UTC
Japanese: https://www.youtube.com/watch?v=k85mY76WO2w
Simultaneous English translation: https://www.youtube.com/watch?v=6UngQqiEWxQ

The press conferences will also be broadcast online on YouTube.
・ Before capsule collection, Dec. 4 (Fri) 16:00 ~ JST = December 4 (Fri), 7:00 UTC
・ After capsule collection, Dec 6 (Sun) 16:30 ~ JST = December 6 (Sun), 7:30 UTC
JAXA official channel list: https://www.youtube.com/channel/UCAhnRoLLxjp7saH0xsH9yxQ
JAXA Sagamihara channel list: https://www.isas.jaxa.jp/outreach/announcements/002507.html

[MahFL]

The English translation links are in Japanese for me...

[Explorer1]

English for the capsule separation here:

https://youtu.be/zw_ZUQeMQww

Full English playlist here:

https://www.youtube.com/playlist?list=PLAOO...pWjEmxEfj_CgCqP

[MahFL]

Thank you Explorer.

[Marcin600]

Capsule Separation Operation: "Everything is successful and great"

„Kyoto University's Seimei telescope was able to capture pictures of Hayabusa2 and the separated capsule”

https://www.kwasan.kyoto-u.ac.jp/general/fa...busa2_20201205/

video - https://www.youtube.com/watch?v=8CqTDwUu5LU

picture - Credit: Kyoto University Okayama Astronomical Observatory (I translated the annotations):

Attached thumbnail(s)

 

[Marcin600]

Pictures of Hayabusa2 and the separated capsule were also taken by another telescope - 103 cm reflecting Kirat telescope at Astro Park in Tottori City - https://www.city.tottori.lg.jp/www/contents...9585/index.html

[Marcin600]

Mission Control Live: Hayabusa2 Capsule Reentry Operation (with English translation) starts now - https://www.youtube.com/watch?v=Dq_6FRV91Hs...eature=youtu.be