Asteroid explorer, Hayabusa2,reporter briefing

February 4, 2021
JAXA Hayabusa2 ProjectTopics
Overview
1. Operation status of the spacecraft
2. Curation work
3. Results from the LIDAR optical link experiment
4. Introduction to the NIRS3 journal paper
5. Introduction to the LIDAR journal paper
6. Future plans
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Hayabusa2 reporter briefing

2Overview of current status
Spacecraft operation• The ion engine operation for the Extended Mission began on
January 5. Powered navigation time so far is 577 hours.
Curation work• The sample of particles and bulk powder returned from Ryugu havebeen moved to observation containers, and high-definition optical
microscope images are being acquired, along with measurements of
the weight.
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Hayabusa2 reporter briefing3

1. Operation status of the spacecraft• Ion engine operations resumed on January 5.
• The cumulative powered navigation time was 9,514 hours before returning to Earth,but exceeded 10,000 hours on January 26 (10,091 hours on January 31st)• To save propellent, priority was given to high efficiency (specific impulse) andthree engines were operated with a modest thrust of about 8 mN/engine. (Thiscorresponds to the maximum thrust at the time of Hayabusa.)• The mission record for the shortest solar distance is now updated; it was 0.853 au(astronomical units) when ion engine operations stopped on January 30. This isslightly below the shortest solar distance of 0.86 au experienced during the ion
engine operations of Hayabusa.
• The powered navigation time from January 5th to January 31st was 577 hours.
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Hayabusa2 reporter briefing41. Operation status of the spacecraft On January 5, 2021, the operation beganwith 3 ion engines, BCD
 Deceleration direction with respect toorbit
Cumulative operation time for the ionengines (as of January 31, 2021)
A: 6705 hours
B: 611 hours
C: 8652 hours
D: 8106 hours
IES (powered navigation) : 10091 hours
Intermittent operation until around
November, then pause for a time.
image creditJAXA
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Hayabusa2 reporter briefingtime
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2. Curation work

• The sample in chamber A was placed in observation containers (3 dishes
in total: see figure below), and the weight measurement and opticalmicroscope observations were started.
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Hayabusa2 reporter briefing

63. Result of the laser ranging experiment
A 2-way laser link between Hayabusa2 and ground stations was successful using the echo transponder method.
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The Cote d'Azur Observatory in France received the downlink signal from theHayabusa2 LIDAR and successfully established the 2-way link.
Dec. 9, 2020:
1 million km
Dec. 21, 2020 : 6 million km
The signals detected by other stations are under analysis.

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3. Result of the laser ranging experiment
UplinkThree stations (Koganei, Mt.Stromlo, Grasse) successful.
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Grasse station successful.

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3. Result of the laser ranging experiment
Example of a successful laser link between a planetary explorer and ground stations
2005 Messenger 24million km Asynchronous 2-Way
2005 Mars Global Surveyor 80million km 1-Way
2009 Lunar Reconnaissance Orbiter 0.385million km 2-Way2013 Lunar Laser Communication Demonstration 0.385million km 622Mbps
2015 Hayabusa2 6.6million km 1-Way
2020 Hayabusa2 6million km Synchronous 2-Way
The 2-way link between Hayabusa2 and the Earth station is rare success example that could be achieved in cooperation with foreign
institutions.

Results and Significance- One station succeeded in 2-way link and three stations succeeded in 1-way link.
- First example of 2-way link between a planetary probe and a ground station by a echo transponder.
- Successful downlink detection in daytime when there is a lot of noise from the Sun.
- Measurement of LIDAR's field-of-view by the stable uplink.
- Technology accumulation for future deep space laser ranging and high precision orbit determination.
- The successes was achieved by cooperation with foreign laser stations.
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Hayabusa2 reporter briefing

94. NIRS3 paper introduction
Overview• A paper on the research results from direct observations ofsubsurface material on asteroid Ryugu using the Near-Infrared
Spectrometer (NIRS3) was published in the British online journal,Nature Astronomy, on January 4, 2021 (January 5 JST).

• The research reports that the subsurface material on Ryugu has
undergone partial dehydration due to heating, similar to thesurface material. However, it is water-rich compared to that of thesurface. Heating would therefore have occurred on the parent
body that is the predecessor of Ryugu.
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Hayabusa2 reporter briefing10

4. NIRS3 paper introduction
Title

Paper details

Thermally altered subsurface material of asteroid (162173) RyuguAuthors Kohei Kitazato1Ralph Milliken2Takahiro Iwata3,4Masanori Abe3,4 
Makiko Ohtake1
96 other authors
Corresponding author1University of Aizu2Brown University3JAXA
4Graduate University for Advanced Studies (SOKENDAI)32 otherinstitutes
Journal Nature Astronomy

Publication date 2021/1/4 1/5 JSTDOI2021/2/4

https://doi.org/10.1038/s41550-020-01271-2
Hayabusa2 reporter briefing11

4. NIRS3 paper introduction "from Kitazato et al. (2021))

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Hayabusa2 reporter briefing12

4. NIRS3 paper introduction     

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2021/2/4

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4. NIRS3 paper introduction

Summary of observation results & interpretation

subsurfacesurface
Difference

Similarity

Observation resultsInterpretation

Subsurface material has slightly
deeper absorption for thehydroxyl groups than the surface,indicating water rich.

After the formation of Ryugu, a part of surface
water was lost through heating in sunlight orspace weathering.

Both the subsurface and surface
material have a narrow absorption
width for the hydroxyl groups,indicated partial dehydration attemperatures above 300˚C

Even if Ryugu once orbited closer to the Sunthan at present, temperatures of subsurface
material would only have reached 200˚C fromsunlight heating.
Ryugu material has been thermally
metamorphosed by internal heating or impact
heating of the parent body.
Paper shows this via numerical calculation

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Hayabusa2 reporter briefing

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5. LIDAR paper introduction• The following 3 papers have been released by the Laser
Altimeter (LIDAR) team.
• By making full use of the distance data collected in the vicinityof the asteroid using the laser altimeter, the orbit of thespacecraft could be accurately determined. This was used in theanalysis of the camera images and forms the bases fordeveloping useful technology for the up-coming Martian Moons
eXploration (MMX) mission.
MatsumotoNAOJ et al. Icarus, 2020/3
YamamotoNAOJ et al. EPS 2020/6
NodaNAOJ et al. EPS 2021/1

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Hayabusa2 reporter briefing15

5. LIDAR paper introduction #1
Matsumoto, K., and 39 colleagues, “Improving Hayabusa2 trajectory by combining LIDAR data and a shapemodel”, Icarus, 338, 113574, https://doi.org/10.1016/j.icarus.2019.113574, Publication date: 2020/3/1•••

The orbit of the spacecraft was improved by fitting the time series for the topographical information from theLIDAR ranging data to the shape model.
Orbit estimation is possible even during a period when there is no Doppler tracking or image data.
The improved spacecraft trajectory was also used for the data analysis from other observational instruments.

LIDAR
Footprint

Residualtime series

From Matsumoto et al. (2020)2021/2/4

Hayabusa2 reporter briefing16

5. LIDAR paper introduction #2•••

Yamamoto, K. and 37 colleagues, “﻿Dynamic precise orbit determination of Hayabusa2 using laser altimeter(LIDAR) and image tracking data sets”, Earth Planets and Space (2020) 72: 85, ﻿https://doi.org/10.1186/s40623020-01213-2, Publication date 2020/6/12
The orbit of the spacecraft geometrically determined through terrain fitting was improved by using the distancemeasurement data obtained from the LIDAR laser altimeter and the image center data from the ONC-W1 camera.
This is expected to be useful not only for the Hayabusa2 mission, but also for future missions to small celestialbodies as a method for obtaining precise orbits.

Red LIDAR footprint position calculated from terrain fitting trajectoryBlue LIDAR footprint position calculated using the orbit of this study.

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From Yamamoto et al. (2020)

https://www.miz.nao.ac.jp/rise/c/reading/paper-detail-20200706

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Hayabusa2 reporter briefing17

5. LIDAR paper introduction #3•

Noda, H., and 51 colleagues,“Alignment determination of theHayabusa2 laser altimeter (LIDAR)”,
Earth, Planets and Space volume 73,
Article number: 21 (2021),
https://doi.org/10.1186/s40623-02001342-8, Publication date 2021/1/20•

The LIDAR time series data wascompared with the ONC-T images toaccurately determine the orientation ofthe LIDAR instrument. This
contributes to the refinement of thespacecraft trajectory estimated fromthe LIDAR data.
2021/2/4

From Noda et al., 2021

Hayabusa2 reporter briefing18

6. Future plans
Operation Schedule
2021/2-3
Ion engine operation testwhen the solar distance is smallPress and media briefings
2021/2 or 3 TBD
Press briefing @ online

2021/2/4

Hayabusa2 reporter briefing

19Reference

2021/2/4

Hayabusa2 reporter briefing

20Overview of Hayabusa2Objective
We will explore and sample the C-type asteroid Ryugu, which is a more primitive type than the S-type asteroidItokawa that Hayabusa explored, and elucidate interactions between minerals, water, and organic matter in theprimitive solar system. By doing so, we will learn about the origin and evolution of Earth, the oceans, and life, andmaintain and develop the technologies for deep-space return exploration (as demonstrated with Hayabusa), a field
in which Japan leads the world.
Expected results and effects
By exploring a C-type asteroid, which is rich in water and organic materials, we will clarify interactions between
the building blocks of Earth and the evolution of its oceans and life, thereby developing solar system science.
 Japan will further its worldwide lead in this field by taking on the new challenge of obtaining samples from acrater produced by an impacting device.
We will establish stable technologies for return exploration of solar-system bodies.
Features:World’s first sample return mission to a C-type asteroid.
World’s first attempt at a rendezvous with an asteroid and performance of observation before and after projectile
impact from an impactor.
Comparison with results from Hayabusa will allow deeper understanding of the distribution, origins, andevolution of materials in the solar system.
International positioningJapan is a leader in the field of primitive body exploration, and visiting a type-C asteroid marks a newaccomplishment.
This mission builds on the originality and successes of the Hayabusa mission. In addition to developing planetaryscience and solar system exploration technologies in Japan, this mission develops new frontiers in exploration ofprimitive heavenly bodies.
NASA too is conducting an asteroid sample return mission, OSIRIS-REx (launch: 2016; asteroid arrival: 2018;
Earth return: 2023). We will exchange samples and otherwise promote scientific exchange, and expect further
scientific findings through comparison and investigation of the results from both missions.

2021/2/4

Hayabusa2 reporter briefing(Illustration: Akihiro Ikeshita)

Hayabusa 2 primary specifications
MassApprox. 609 kg
Launch3 Dec 2014
MissionAsteroid return
Arrival27 June 2018
Deoarture
13 Mov 2019
Earth return6 Dec 2020 (plan)
Stay at asteroid Approx. 18 months
Target body
Near-Earth asteroid Ryugu

Primary instruments
Sampling mechanism, re-entry capsule, optical cameras, laser
range-finder, scientific observation equipment (near-infrared,thermal infrared), impactor, miniature rovers.

21

1. Current project status & schedule overview
Scheduleoverview

2015
12

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Hayabusa2 reporter briefing

22Mission flow
LaunchDec 3, 2014

Earth swing-by
Dec 3, 2015

MINERVA-II1 separation
Sep 21, 2018

Ryugu arrival
June 27, 2018

Target marker
separation
Oct 25, 2018

Ryugu
departure
Nov 13, 2019

Targetmarker
Dec. 6, 2020
MINERVA-II2 separation
separation
Sept. 17,
(image credit: illustrations including spacecraft
Oct. 3, 20192019
by Akihiro Ikeshita, others by JAXA)

Earth return2021/2/4

MASCOT
separation
Oct 3, 2018

Secondtouchdown
July 11, 2019

Targetmarker
separation
May 30,2019

Hayabusa2 reporter briefing

Impactor (SCI)
5 April, 2019

First touchdown
Feb 22, 201923

Clean chamber overview
CC3-1
Opening the sample container undervacuum environment
CC3-2
Sample collection under vacuum
CC3-3
Transition from vacuum to nitrogenenvironment
CC4-1
Handling of submillimeter-sizedparticles

 CC4-2
Handling / observation / sorting ofrelatively large particles (> mm)  

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Hayabusa2 reporter briefing

24Reference: Catcher opening operationA
B
C

Particles areconfirmed
from abovechamber Ap

The sample catcher was moved to clean chamber CC3-2, and the lid of sample catcher chamber A was opened invacuum conditions.

pMany particles are confirmed to be in chamber A. This is thought to be the sample collected during Touchdown#1 on Ryugu.

pPart of the sample was picked up in Chamber A to be stored in vacuum in its present condition.

p

From here, we will move to chamber CC3-3, remove the samples from chamber A in a nitrogen environment,
and open chambers B and C.

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Hayabusa2 reporter briefing

25ReferenceObservation container

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Hayabusa2 reporter briefing

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