Asteroid explorer, Hayabusa2,
reporter briefing

June 11, 2019
JAXA Hayabusa2 ProjectTopics
Regarding Hayabusa2,
 Results from the low altitude descent observation
operation PPTD-TM1A
 Plan for the low altitude descent observation operation
PPTD-TM1B
Future operations
Science results

2019/06/11

Hayabusa2 reporter briefing

2

Contents
0. Hayabusa2 and mission flow outline
1. Current status and overall schedule of the project
2. Low altitude descent observation operationPPTD-TM1Aresults
3. Low altitude descent observation operation PPTD-TM1Bplans
4. Future operation plans
5. Science results
6. Other topics
7. Upcoming events

2019/06/11

Hayabusa2 reporter briefing

3Overview of Hayabusa2
Objective
We will explore and sample the C-type asteroid Ryugu, which is a more primitive type than the S-type asteroid
Itokawa 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.

2019/06/11

Hayabusa2 reporter briefing

Hayabusa 2 primary specifications(Illustration: Akihiro Ikeshita)
Mass
Approx. 609 kg
Launch3 Dec 2014
MissionAsteroid return
Arrival27 June 2018
Earth return2020
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.

4

LaunchDec 3, 2014

Mission flow
Earth swingby Dec 3, 2015

Ryugu arrival

MINERVA-II-1 separation

June 27, 2018

Sep 21, 2018

MASCOT
separation

March 10, 2018

Ryugu departure

Feb 22, 2019NovDec, 2019

Earth return
End of 2020

After confirming safety,
touchdown at or near crater area
to collect subsurface material.

Impactor (SCI)(image credit: illustrations including spacecraft by Akihiro Ikeshita, others by JAXA)

2019/06/11

Hayabusa2 reporter briefing

5 April, 2019

completed → First touchdown5

1. Current project status & schedule overview
Current
status9– From May 28 ~ 30, the low altitude descent observation operation (PPTM-TM1A)
was performed. A target marker was dropped in the CO1 region and low altitude
observations were performed.
– From June 11 ~ 13, the low altitude descent observation operation (PPTM-TM1B)
will be performed. Today (6/11) we are preparing for the descent.
2015

Schedule
overview

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Hayabusa2 reporter briefing

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2. Low altitude descent observation operation(PPTD-TM1A) results• The low altitude descent observation operation (PPTD-TM1) was performed
between May 28 30.
• Preparations were made for the descent (May 28) which began on May 29 12:06
JST (on-board time) and reached an altitude of about 35m on May 30 at 11:00 JST.
The spacecraft then hovered around this altitude.
• The spacecraft began to descend again at 11:09, and the target marker was
separated at 11:18 at an altitude of about 9m. Then the spacecraft began to rise.
The lowest altitude reached was about 8m.
• The spacecraft returned to the home position on May 31.
• The target marker was dropped about 3m away from the target point.
• We were able to get the characteristics of the measurement data for the Laser
Altimeter (LIDAR) and Laser Range Finder (LRF) at low altitude, as well as
characteristics of the images of the target marker captured by Optical Navigation
Camera – Wide angle (ONC-W1) .
2019/06/11

Hayabusa2 reporter briefing7

2. Low altitude descent observation operation(PPTD-TM1A) results
Second target marker dropped successfully!

A

B C D

E

This time A was separated. B is alreadyseparated. Separation order
B→A→E→C→D
2019/06/11

Target marker• Body (ball) sizeabout10cm diameter• Retroreflective film on the surface• 4 bars rolling prevention• Many polyimide small balls inside• All five target markers contain a sheetwith the names of members of thegeneral public.
• Total number of names listed183,174.
You can search for the location of a name here
https://www.haya2-campaign.jp/
Hayabusa2 reporter briefing

Target marker A separated.

Sheet ofnames

8

2. Low altitude descent observation operation(PPTD-TM1A) results
PPTD-TM1A operation (actual)
altitudeHome position return

Home position

20km

Deceleration
ΔV

5km

Targetmarkerseparation~35m

Onboard time
Ground time
2019/06/11

Closest target point
target marker
drop point
||C01 area
Rising ΔV

5/29 12:06
5/29 12:21

22:26
23:41

5/30 11:00 11:18
5/30 11:15 11:33
Hayabusa2 reporter briefing

time
5/31

(JST)

image credit: JAXA
9

2. Low altitude descent observation operation(PPTD-TM1A) results

Low altitude sequence during PPTD-TM1A operation (actual)  !   !    "       &   &       !       #  !       !  !     

 !      !   " !        !    !   %    &  !  
 !           ! 

 !   !    !        ! "    





  


35m

11:09
   $     !    !   %           !   

 





11:00



11:00 Time when
altitude reachedabout 35m.
11:09 Time whendescent began.
11:18 Time when
the TM
separated andrise began   

Time is JST
ground time on
May 30, 2019 '! !   "      !   " !   !  ! "   !          $  !        !    "      !

8m

   11:18

  0m
(image credit: JAXA)

2019/06/11

Hayabusa2 reporter briefing10

2. Low altitude descent observation operationn(PPTD-TM1A) results
Touchdown candidate sites
L14 area
L14-C

L14-A
L14-B

C01 area
C01-C
C01-A
C01-B

S01 area

Near SCI
collision L12-A2
point

L12-A4

L12-D

L12-A3
L12-A1(image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya
University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST)

2019/06/11

Hayabusa2 reporter briefing11

2. Low altitude descent observation operation(PPTD-TM1A) results
Target marker drop resultsl Succeeded in dropping TM into “area accessible for TD”.
New

Area accessible for TD

Target point for TM
SCI crater

TM
Target Marker

Image taken by ONC-W1 on May 30 at 11:23
JST (ground time). Image altitude about 35m.

Explanatory
diagram: actualand planned
TM location
are plotted.

(image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST)

2019/06/11

Hayabusa2 reporter briefing122. Low altitude descent observation operation(PPTD-TM1A) results
Separation image of the target marker (by ONC-W1)

New

animation
Composition of continuous sequence of images from ONCW1 taken on May 30 between 11:18 – 11:26 JST (onboardtime). Spacecraft altitude is from 8m – 68m. Images taken
Credit: JAXAChiba Inst. of Tech.
with flash.
2019/06/11

Animation over roughly the same time period as
image on left. Shot with flash. Credit: JAXA

Hayabusa2 reporter briefing13

2. Low altitude descent observation operation(PPTD-TM1A) results
Separation image of the target marker (by CAM-H)

Target marker shadow

Target marker

Image taken by CAM-H on May 30, 2019 at 11:18
JST (onboard). The spacecraft altitude is about 8m.
2019/06/11

Images taken by CAM-H on May 30, 2019 from 11:18
JST. The altitude rose from about 8m to about 15m.

Hayabusa2 reporter briefing(animation 10x speed)Image credit: JAXA
14

2. Low altitude descent observation operation(PPTD-TM1A) results

Comparison with the first target marker drop (TD1-R3)
l The error in the target marker position (distance from the target point) was 15m for
TD1-R3 but reduced to 3m for PPTD-TM1A.
L08-B1 area

3m

Area accessible for TD

Target point for TM
L08-E1 area

SCI crater(image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST)

2019/06/11

Hayabusa2 reporter briefing15

2. Low altitude descent observation operation(PPTD-TM1A) results
Descent orbitPPTD-TM1A
Reference trajectory
Image measurements
Estimated trajectory

Reference trajectory
Image measurements
Estimated trajectory

The descent followed the reference trajectory
2019/06/11

Hayabusa2 reporter briefing16

2. Low altitude descent observation operation(PPTD-TM1A) results
Reference: Descent orbit for TD-R3 operation on Oct 25, 2018
Reference trajectory
Image measurements
Estimated trajectory

Reference trajectory
Image measurements
Estimated trajectory

Movement was back-and-forth past the reference trajectory
2019/06/11

Hayabusa2 reporter briefing17

2. Low altitude descent observation operation(PPTD-TM1A) results

Accuracy improvement factors– Design of navigation guidance control system• Parameters that make difficult to pass the reference
orbit.

– Asteroid gravity model update• Improved consideration of the asteroid shape– Operation sequence change• Target marker dropped from hovering.
2019/06/11

Hayabusa2 reporter briefing18

3Plan for low altitude descent observation
operation (PPTD-TM1B)lSpacecraft operation from June 11 – 13, 2019.

l

Descend to the C01 region and observe the artificial crater.

Acquire and store data for low-altitude spacecraft operation
checks.
l No new target marker will be dropped.
l2019/06/11

Hayabusa2 reporter briefing

193Plan for low altitude descent observation
operation (PPTD-TM1B)
PPTD-TM1B operation
altitude
Return to home position

Home position

20km

Descent target point||
C01

Deceleration
ΔV

5km
~35m

On-board time 6/12 11:40
Ground time 6/12 11:54

Rising ΔV
22:00
22:14

6/13 10:34 10:57
6/13 10:48 11:11

Times in actual operation may vary.
2019/06/11

time
6/14

(JST)

image credit: JAXA
Hayabusa2 reporter briefing20

3&Plan for low altitude descent observation
operation (PPTD-TM1B)
Low altitude sequence for PPTD-TM1B
                            "    #  !                                                              !       


35m

  










                    "          

 

10m

0m
C01

$image credit: JAXA%
2019/06/11

Hayabusa2 reporter briefing21

4. Future operation plans Operation plan concept from May ~ Julyupdated information
• Currently, Ryugu is approaching the Sun (perihelion in September). It will only be possible to land on
Ryugu until the start of July, after which the asteroid temperature will rise.
• By the middle of June, the crater and state of the spacecraft will have been examined and it will then be
decided if a second touchdown operation will be performed between the end of June and start of July.
• Target point: Area where there is ejected material from the artificial crater.
• Operation name: “Pinpoint touchdown” (PPTD).
• 2 or 3 low altitude descent observations will be performed in May and June before the PPTD operation.
While performing detailed topographical observations of the landing point candidates, a target marker
will be dropped as a guide for landing in this region.
• 1st 5/145/16
Operation namePPTD-TM1 → target marker could not be dropped• 2nd 5/285/30
Operation namePPTD-TM1A → target marker dropped successfully• 3rd 6/116/13
Operation name: PPTD-TM1B → target marker not dropped• During PPTD-TM1A operation, a target marker was dropped in CO1-C. Currently, we are investigating
the possibility of touchdown in CO1-C.
2019/06/11

Hayabusa2 reporter briefing22

4. Future operation plans

Project judgement for whether to perform the second touchdown operation
Scientificandengineeringvalue

Operation
feasibility

Spacecraft
status2019/06/11

Judgement items

Current status

JudgedIs there a high probability in collecting artificial craterejecta?

For sites is close to the artificial crater, it is very
likely ejecta is on the surface.

Is the scientific value high enough?

Subsurface collection, multiple collection andincreased collected volume are all very valuable.

Is the engineering value high enough?

There is high engineering significance indemonstrating the world’s first multi-sampling andsubsurface sampling.



Do we have the terrain information needed fortouchdown?

Terrain information necessary for touchdown was
obtained from PPTD-TM1 and PPTD-TM1A.



Proximity of the target marker to the touchdown target
point.

Target marker landed 3m from the center of C01-C.



Can we design a sufficiently safe touchdown sequence?

Under consideration.

Is there any problem with the optical system where theamount of light received has decreased due to dust in thefirst touchdown?

Under consideration.

Hayabusa2 reporter briefing23

4. Future operation plans

Ejecta from the SCI crater near C01

30m
20m

C01-C



• Ejecta from the SCI crater (darker colors than
the surroudings) is distributed all over the
PPTD candidate site, C01-C.
• The average thickness of the ejecta in C01-C
is estimated at about 1cm, based on the spatial
distribution of the darkening.
• The C01-C ejecta is thought to be a mix of
excavated material from depths of 0m to about
1m.  Layers of several 10s cm or more are
predicted from space weathering, solar heating andcosmic rays.

New

Terrain created by adjusting lighting conditions in the ONC image.

(JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya
Change in reflectance before and after SCI impactCRA1
University, Chiba Institute of Technology, Meiji University, University of Aizu,→ CRA2Contrast emphasized. Black areas darkened
AIST)
after collision
24
Hayabusa2 reporter briefing
2019/06/11

5. Science results
Paper published In Icarusby Tatsuhiro Michikami (Kindai University)• Michikami, T (Kindai Univ)., and 35 colleagues, 2019. “Boulder size and shape distributions on asteroid
Ryugu.” Icarus 331, 179-191. https://doi.org/10.1016/j.icarus.2019.05.019 Published2019/5/21• The size and shape of more than 10,000
boulders were measured across asteroid
Ryugu. There are about 4400 boulders
larger than 5m and they have a shapeconsisted with collision fragments. Thissuggests most of the boulders are
fragments formed in the collisional
destruction of Ryugu’s parent body.
• The number of boulders (per unit area)
over 10m is larger than any asteroid
explored so far.
by Michikami et al., 20192019/06/11

Hayabusa2 reporter briefing25

5. Science results
Michikami, et al. 2019: main conclusioms
 Boulder distribution (global) [above 5m]

The number density of boulders above 10m is higher than that of other asteroids, but the power of the size
distribution is relatively gentle at -2.65 (meaning that there are relatively few smaller boulders for each large
boulder) → Rubble pile object that has experienced an intense collision. Small rocks are buried.

 Number density of rocks by longitude & latitude

Overall, uniform. Slight differences in the east-west direction. The number density of boulders
near the equator is small. → Many boulders near the equator are buried.

 Size distribution of boulders in close-up images (2cm – several m)
The smaller the boulders, the smaller the slope of the power-law.

buried boulders(Michikami et al., 2019

→ The smaller the boulder, the more are buried.

 Shape of boulders (bi-axial ratio)

Smaller boulders or those closer to the equator have an average axial ratio (b/z) that is closer tothe collision debris shape. → these have moved more.
2019/06/11

Hayabusa2 reporter briefing26

6. Other topics
Award winner!
COOL JAPAN ConferenceØ Winner of COOL JAPAN AWARD 2019Ø For Hayabusa & Hayabusa2
Ø Award ceremony5/27, Kyoto Gyoen National
Garden

2019/06/11

AIRBUSØ Received the “Hayabusa2 Special Award”
from Airbus Space Day
Ø Award ceremony: 6/4Tokyo ConferenceCenter (Shinagawa)Ø AIRBUS was involved in the equipment for
the MASCOT lander.

Hayabusa2 reporter briefing27

7. Upcoming events
Operation plans:• June 1113Low altitude descent observation operation (PPTDTM1B)
Press & media briefings• June 25 15:00 Press briefing session @ Tokyo Office

2019/06/11

Hayabusa2 reporter briefing

28

Press briefing session, part II
Individual Q & A

Investigation and preparation for the second touchdown

2019/06/11

Hayabusa2 reporter briefing

29

Hayabusa2 Mission Success Criteria
Mission goal

Minimum success

Full success

Extra successScience goal
Investigate the material
characteristics of C-type asteroids.
In particular, clarify the interaction
between minerals, water andorganic matter.

Provide new insights on thesurface material of C-type
asteroids by observations in thevicinity of the asteroid.

Obtain new findings on mineralwater-organic interactions by the
initial analysis of the collected
samples.

Integrate astronomical & microscale
information to create new scientificresults regarding materials for Earth,sea and life.

Science goal
Investigate the formation processof asteroids by direct exploration of
the asteroid’s reaccumulation
process, internal structure andsubsurface material.

Provide insights on the internal
structure of the asteroid byobservations in the vicinity of
the asteroid.

Obtain new knowledge on thePresent scientific results on asteroidinternal structure and subsurface
formation based on new findings
material of the asteroid byregarding the collision destruction &observing the phenomena caused byreaccumulation process.
collisions with an impacting body.
New scientific results from the
exploration robots on the surface
environment of asteroids.

Engineering goal
Improve robustness, accuracy andoperability of the new technology
implemented in Hayabusa, andmature it as a technology.

Rendezvous with a target orbit
Drop the exploration robot to theusing ion engines for deep spaceasteroid surface.
propulsion.
Take a sample of the asteroid
surface.
Collect the re-entry capsule on
Earth.

Engineering goal
Demonstrate impact object
colliding with a celestial body.

Construct a system to allow animpact device to collide withthe target object and performthat collision with the asteroid.

2019/06/11

Make the impact device collide in a
specified area.

Hayabusa2 reporter briefing

Achieved
Awaiting
achievement
confirmation

N/A

Collect a sample of asteroid
subsurface material exposed during
the collision.

Currentaim
30

Conditions for execution of the 2nd touchdown
Project judgement for whether to perform the second touchdown operation

Scientificandengineeringvalue

Operation
feasibility

Spacecraft
status2019/06/11

Judgement items

Current status

JudgedIs there a high probability in collecting artificial craterejecta?

For sites is close to the artificial crater, it is very
likely ejecta is on the surface.

Is the scientific value high enough?

Subsurface collection, multiple collection andincreased collected volume are all very valuable.

Is the engineering value high enough?

There is high engineering significance indemonstrating the world’s first multi-sampling andsubsurface sampling.



Do we have the terrain information needed fortouchdown?

Terrain information necessary for touchdown was
obtained from PPTD-TM1 and PPTD-TM1A.



Proximity of the target marker to the touchdown target
point.

Target marker landed 3m from the center of C01-C.



Can we design a sufficiently safe touchdown sequence?

Under consideration.

Is there any problem with the optical system where theamount of light received has decreased due to dust in thefirst touchdown?

Under consideration.

Hayabusa2 reporter briefing

31Engineering value• Multi-sampling (sampling from multiple points on one celestial body) andsubsurface sampling (collection of artificial crater ejecta) are challenges
that humanity has not yet achieved. It is a technology that candramatically increases the freedom of space exploration.
• The main technologies related to sample return (electric propulsion
navigation, optical navigation, sampling, re-entry) were achieved by
Hayabusa, but multi-sampling and subsurface sampling are unexploredtechnologies that were planned with Hayabusa2, along with artificial
crater generation.
• Multi-sampling is an operation that requires comprehensive reliability andtechnology accumulation, including hardware and software reliability forthe spacecraft and operation technology (human skill).
2019/06/11

Hayabusa2 reporter briefing

32

Science value (by Sei‘ichiro Watanabe)• The second planned touchdown point (C01-C) is close to the SCI crater and there is a high possibility that
subsurface material excavated from the crater has been deposited on the surface.
• Subsurface material is a valuable sample as through comparison with the first surface sample collected, it canbe used to evaluate the impact of the solar wind and cosmic ray generation on the asteroid surface.
• If degeneration is weak, information regarding the formation period of the Solar System should be acquired indetail. Subsurface materials are particularly valuable for sensitive organics.
• The mixing process and its timescale on the asteroid surface can be constrained.
• The extend of regional heterogeneity of celestial bodies can be clarified from the comparison of multiple point
samples.
• OSIRIS-REx excels at sample volume, but only from a single point. If Hayabusa2 can obtain samples frommultiple points, it will be an qualitatively unmatched outcome.
• This can be expected to be a valuable sample that will be the key to directly connected Hayabusa2 science(remote observation, collision experiment, returned sample analysis).
• Collecting several samples successfully will prove that the sampling operation of Hayabusa2 has been
established with high reliability.
2019/06/11

Hayabusa2 reporter briefing

33Ejecta from the SCI near C01
30m
20m

by Seiji Sugita
Ejecta from the SCI crater near C01

C01-C



• Ejecta from the SCI crater (darker colors than
the surroudings) is distributed all over the
PPTD candidate site, C01-C.
• The average thickness of the ejecta in C01-C
is estimated at about 1cm, based on the spatial
distribution of the darkening.
• The C01-C ejecta is thought to be a mix of
excavated material from depths of 0m to about
1m.  Layers of several 10s cm or more are
predicted from space weathering, solar heating andcosmic rays.

Terrain created by adjusting lighting conditions in the ONC image.

(JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya
Change in reflectance before and after SCI impactCRA1
University, Chiba Institute of Technology, Meiji University, University of Aizu,→ CRA2Contrast emphasized. Black areas darkened
AIST)
after collision
New
34
Hayabusa2 reporter briefing
2019/06/11

Expectation for the second touchdown from material
analysis scienceby Hikaru Yubata Reveal the cause of the “black substance” characteristic of Ryugu•
The reflectance of the Ryugu surface is lower than that of any known meteorite and various possibilities have been
speculated as to its origin (organic carbon composition, iron sulphide / iron oxide composition, modification by heatand space weathering, particle size etc). The fact that the reflectivity is lower in the artificial crater than at thesurface suggests that the black material may be a component before being subjected to surface modification, or it
may be a product of the SCI collision experiment. Chemical analysis of a second sample is essential to clarify thecause.
 High quantity of (possibly) organic chemical information•
Amino acids, carboxylic acids, hydrocarbons, nucelobases etc, are hardly detected (reported in the 80-90s) in
carbonaceous meteorites that that undergone heating (similar in spectrum to the surface material of Ryugu). In
addition to this, thermal decomposition and carbonization of insoluble high molecular weight organic compounds
occur. Therefore, if a weakly modified sample can be collected during a second touchdown, the type and quantity oforganic molecules obtained will increase, and the acquisition of clues to clarify the origin of the Solar System andlife will be overwhelmingly improved.
•
From the surface sample collecting in the first touchdown, we may discover new kinds of organic molecules that canbe synthesized (not only decomposed) by solar heating and space weathering. Analysis of a subsurface sample will
be very important as a comparison to understand the formation process.
•During observations, organic matter has not been identified. For Hayabusa2, sample analysis is the only means oforganic matter characterization.
2019/06/11

Hayabusa2 reporter briefing

35Hayabusa2 clean chamber for receiving the returned
sampleby Masanao Abecredit: JAXA
2019/06/11

Hayabusa2 reporter briefing

36