Asteroid explorer, Hayabusa2,
reporter briefing

April 11, 2019
JAXA Hayabusa2 ProjectTopics
Regarding Hayabusa2,
Small Carry-on Impactor (SCI)
operation results
Crater Search Operation (Post-SCI

2019/04/11

Hayabusa2 reporter briefing

2

Contents
0. Hayabusa2 and mission flow outline
1. Current status and overall schedule of the project
2. Small Carry-on Impactor (SCI) operation results
3. Imaging with the deployable camera (DCAM3)
4. Crater Search Operation (Post-SCI)
5. Other topics
6. Future plansReference material
2019/04/11

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.

2019/04/11

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

Mission Flow
Launch3 Dec 2014

Earth returnlate 2020

Sampleanalysis
2019/04/11

Earth swing-by
3 Dec 2015

Arrival at asteroid
June 27, 2018
Examine the asteroid
by remote sensing
observations. Next,
release a small lander
and rover and also
obtain samples fromthe surface.

Depart asteroid
Nov–Dec 2019

Releaseimpactor
Create artificial
craterAfter confirming safety,
touchdown within the craterand obtain subsurface samples
Hayabusa2 reporter briefing

Use an impactor to create an
artificial crater on the asteroid’s
surface(Illustrations: Akihiro Ikeshita)51. Current project status & schedule overview
Current – On April 5 at 11:56 JST (on-board time) the Small Carry-on Impactor (SCI) separated
from the spacecraft. The separation of the SCI and ejector from the surface of Ryugu
status9
were confirmed via images, and the impact experiment is considered a success.
– As of April 11, Hayabusa2 is on its way back to the home position.
2015

Schedule
overview

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Hayabusa2 reporter briefing

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6

2. Small Carry-on Impactor Operation Results
Results from the impact experiment operation• The separation of the Small Carry-on Impactor (SCI) began on April 3, and the SCI
separated from the spacecraft on April 5 at 10:56 JST (on-board time). The SCI
operation has continued since then, and it is expected that the spacecraft will returnto the home position around April 18.
• The separation of the SCI was also confirmed by the Optical Navigation Camera –Wide angle (ONC-W1) and the Thermal Infrared Camera (TIR), in addition toother telemetry.
• The collision of the SCI liner (copper plate) with Ryugu was confirmed withimages captured by the deployable camera (DCAM3).
• Based on the above, the goal of colliding an impactor with Ryugu has beenachieved (one of the minimum successes of engineering goal is completed)• In the future, we will search for the crater that may have been formed.
2019/04/11

Hayabusa2 reporter briefing7

2. Small Carry-on Impactor Operation Results
item

Ground time : JST on-board time

Judgement

Gate 1

4/4 12:12
4/4 13:17 (13:00)

Begin judgement to start descent (@20km)
Decent began

Gate 2

4/4 23:3723:20
4/4 23:55

Decent decelerationΔV40cm/s→10cm/s
Confirm descent continuation 5km)

Gate 3

4/5 09:57

Final separation judgement GO judgement

SCI separation

4/5 11:13 (10:56)

Confirm SCI separation

DCAM3 separation

4/5 11:32 (11:14)

Confirm DCAM3 separation

DCAM3 communication

4/5 11:50

DCAM3 communication check

SCI operation

4/5 11:5311:36
4/5 11:56

SCI explosion time
Confirm state of spacecraft after SCI explosion

Gate 

4/5 13:45

Judgement that SCI separation and evacuation sequence were performed
safely.

Gate 6

4/5 15:12

Judgement to return to home position (GO judgement)

2019/04/11

Hayabusa2 reporter briefing8

2. Small Carry-on Impactor Operation Results
From home position to separation of the SCI

Actual operation
HP-Z coordinate

HP-Z coordinate

Altitude change over time
GCP-NAV
Auto. OFF

Movement in space

GCP-NAVhovering

GCP-NAV
Auto. ON

JST

20km

on-board t ground t

20km

4/4 13:00

13:17

5km

4/4 23:20

23:37

1km

4/5/ 10:44

11:01

     5km
  
1km


LIDAR

V = -0.4 m/s
Descent deceleration ΔV
V = -0.1m/s

TargetaltitudearrivalSCI separation0
On-board time JST)
Ground time

2019/04/11

4/4
13:00
13:17

4/4
23:20
23:37

4/5
10:44
11:01

4/5
10:56
11:13

Hayabusa2 reporter briefing

Time
(JST)

0

HP-X coordinateimage creditJAXA
9

2. Small Carry-on Impactor Operation Results
HP-Z
coordinate

Actual operation    


20km

4/16
HP return ΔV4
HP return

4/13
HP return ΔV3W2 imaging 4
4/15
Sun orientated Spin    
1km


SCI separation 6 mins later
4/5 10:56

4
+ZΔV

-ZΔV1

90s later+XΔV

0-3.5kmtimeon-board JST)
2019/04/02

4/11
HP return ΔV2

W2
imaging 2

4/10
Sun oriented Spinred time from SCI separation

15 mins later-XΔV
18 mins later
DCAM3 separation

4/8
Sun oriented
Spin

5 mins later
asteroid debris
avoidance ΔV(+XΔV)

bluetime from SCI
operation

SCI operation
4/5 11:36
40 mins later
10 mins later
lessen evacuation
speed ΔV(+ZΔV)

W2 imaging 1

4/5 17:14
340 mins later
HP return riseΔV(+ZΔV)

4/5 15:44
250 mins later
begin return to HP ΔV(+XΔV)

Hayabusa2 reporter briefing

Trajectory
controlTCM1
performed

4/9
HP return ΔV1

HP-X coordinate

19 mins later-ZΔV2

100 mins laterstop withdrawal
speed ΔV(+ZΔV)

-20km

W2
imaging 3

100km1km

Movement in
space

4/12
Sun oriented Spin

Successful image of
Ryugu by ONC-W2

4/6
asteroid search migration ΔV(+ZΔV)
4/6
return deceleration ΔV(-XΔV)

image creditJAXA
10

2. Small Carry-on Impactor Operation Results
Operating position for the SCI• Control of the spacecraft position at the time ofseparation is estimated to within a 10m error.
• The estimated separation speed from the image showing
the separation of the SCI is about 20cm/s, almost as
expected.
• The lateral velocity at the time of the SCI separation was
also small.
Although the details are currently being analysed, the heightof the SCI detonation is estimated to be about 300m.

Error range of assume
operating position

Evacuation of the spacecraft• The RCS thruster injection at the time of evacuation was
performed correctly, and the spacecraft was able toevacuate to a safe area.
• At the current time, the spacecraft status is normal.
image creditJAXA
2019/04/11

Hayabusa2 reporter briefing11

2. Small Carry-on Impactor Operation Results
SCI captured with the ONC-W1

SCI captured with the ONC-W1 a
few seconds after separation.

The top of theimage istowards thenorth pole of
Ryugu.
2019/04/11

Separation time: April 5, 2019,10:56 JST (on-board time)(Image credit: JAXA, University of Tokyo, Kochi
University, Rikkyo University, Nagoya University, Chiba
Institute of Technology, Meiji University, University of
Aizu, AIST.)
Hayabusa2 reporter briefing12

2. Small Carry-on Impactor Operation Results
SCI captured by the TIR

About 100m

First releaseAnimation
2019/04/11

Imaging interval 2s
Image integration 0.25s
Number of images30s
Imaging duration 60s
Image height about 500m
The top of the image is towards the northpole of Ryugu. The spacecraft is imaging
while rising.

(Image creditsJAXA, Ashikaga University, Rikkyo University, Chiba Institute ofTechnology, University of Aizu, Hokkaido University of Education, Hokkaido
Kitami Hokuto High School, AIST, National Institute for Environmental Studies,
University of Tokyo, German Aerospace Center (DLR), Max Planck Society for
the Advancement of Science, Stirling University.
Hayabusa2 reporter briefing13

2. Small Carry-on Impactor Operation Results
Location of SCI images approximately 40 minutes before detonation & collision

SCI
The red circle is near target center (around S01). Since
the SCI separated about 40 minutes before detonationand collision, the separation position is approximately
30to the east. Top is the north pole.
(Image creditsJAXA, Ashikaga University, Rikkyo University, Chiba Institute of Technology, University of Aizu, Hokkaido University of Education, Hokkaido Kitami Hokuto High School,
AIST, National Institute for Environmental Studies, University of Tokyo, German Aerospace Center (DLR), Max Planck Society for the Advancement of Science, Stirling University.

2019/04/11

Hayabusa2 reporter briefing

14

2. Small Carry-on Impactor Operation Results
 Plan to return to the HP• 4/8 image of Ryugu with the ONC-W2• 4/9 image of Ryugu even captured by theStar Tracker (STT)• 4/9 the spacecraft was 100km away fromthe asteroid, as planned. dV was
implemented for return to HP.
• Currently, the return to the HP is plannedaround 4/18.
2019/04/11

Hayabusa2 reporter briefing

Ryugu images by the STT on April
9 at 12:42 JST (on-board time). Top
is the north pole of Ryugu.
Image creditJAXA
15

3. Imaging with the deployable camera (DCAM3)
Images from the analog camera

Image about 2 seconds after the SCI detonation.
(Image released at the 4/5 press conference)First release

Image about 25 seconds after the SCI detonation

Image credit: JAXA, Kobe University, Chiba Institute of Technology, University of Occupational and Environmental Health, Kochi
University, Aichi Toho University, University of Aizu, Tokyo University of Science.
2019/04/11

Hayabusa2 reporter briefing16

3. Imaging with the deployable camera (DCAM3)First release

Images from the digital camera

About 185 seconds before SCI detonation

Enlarged and brightness adjusted image

 SCI bodyImage creditJAXAKobe University, Chiba Institute of Technology, Kochi University University of Occupational and Environmental Health 
2019/04/11

Hayabusa2 reporter briefing17

3. Imaging with the deployable camera (DCAM3)
Images from the digital camera

First release

About 14 seconds before SCI operation

About 3 seconds after SCI operation High gain long exposure modeImage creditJAXAKobe University, Chiba Institute of Technology, Kochi University University of Occupational and Environmental Health 
2019/04/11

Hayabusa2 reporter briefing18

3. Imaging with the deployable camera (DCAM3)
Overview of the deployable camera DCAM3 operation
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 $  !  #  %    #  $ % # %+ ,Y-231s1km       #   $ #'   
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02019/04/11

Y+90s
+XΔV

Hayabusa2 reporter briefing.

Y+1098s

DCAM3 separation

Y+2403s

Z+620slessen evacuation
speed ΔV(+ZΔV) %       #    $  # '     #      & %  $         $     $    # %      !  # %    
&  %  %      % %  # *  #     (  

Y+840sXΔV

Y+1160s-ZΔV2Z+300sAsteroid ejector
avoidance ΔV(+XΔV) )! $ 

0

Y: SCI
separation-3.5km/  $  # '  %   $  " &      $ % !

+ZΔV

Y+379s-ZΔV1/

Z: SCI detonation

0

Z+5900s
Stop withdrawal
Z+14900s
speed ΔV(+ZΔV)
Begin HP return ΔV(+XΔV)

1image credit3JAXA2
19

3. Imaging with the deployable camera (DCAM3)
DCAM3 System configuration  "  !
  !

   
  !

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

image credit#JAXA!
2019/04/11

Hayabusa2 reporter briefing20

3. Imaging with the deployable camera (DCAM3)
Mounting method of the analog / digital system         
            

       
     

2019/04/11

Hayabusa2 reporter briefingimage credit!JAXA
21

3. Imaging with the deployable camera (DCAM3)
p 18 minutes after separation,
DCAM3 operated for over 5 hours.

Results of the deployable camera operationp Everything worked according to
the scheduled sequence (details
currently being analysed).
p As planned, the analog systemobserved for 20 minutes and theimages sent via radio to thespacecraft. 500 images are thought
to have been acquired and theseare being analysed (not all images
contain Ryugu).
p The digital system imaged andobserved for 3 hours or more andthe images were confirmed tohave been received by the
spacecraft.
2019/04/11

Hayabusa2 reporter briefing22

4. Crater Search Operation (Post-SCI)
Crater Search Operation (Post-SCI) (CRA2)• Obtain detailed data on the area where the Small Carry-on
Impactor (SCI) appears to have collided.
• Operation scheduleApril 2325• Lowest altitude will be approximately 1.7km

2019/04/11

Hayabusa2 reporter briefing23

4. Crater Search Operation (Post-SCI)CRA2 location

NoteThe observation area for CRA2 is the same as the area observed in advance of the SCI operation by CRA1.
Image creditJAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu,
AIST.)

2019/04/11

Hayabusa2 reporter briefing24

4. Crater Search Operation (Post-SCI)
Plan for the Crater Search Operation (Post-SCI) (CRA2)

The observation will be
conducted while
maintaining an altitude
of about 1.7km.
Image creditJAXA
2019/04/11

Hayabusa2 reporter briefing25

5. Other topics
Operation control room live broadcast (youtube)• Implemented as PR for real-time transmission of
Hayabusa2 and space exploration.
•

Play count As of 2019/4/10 at 15 JST– Japanese edition
109,233– Simultaneous English interpretation 143,281• During the broadcast, we also provided real-time subtitles (summary captions) for
the deaf and hearing impaired.
 Due to the broadcasting system, these subtitles were not displayed on the press center display screen.

what are summary captions These are used to support deaf viewers by conveying the contents
of a story in a written summary. This time, we created live subtitles with assistance from thewritten interpreter group, “Momiji”, in Sagamihara City.
Image creditJAXA

2019/04/11

Hayabusa2 reporter briefing26

5. Other topics
EGUEuropean Geosciences Union
– European Geosciences Union General Assembly 2019 is currently
being held in Vienna, Austria (April 7 – 12).
– On April 9, there was a session on Hayabusa2 and OSIRIS-REx,followed by a lively discussion.
– There were 8 announcements related to Hayabusa2.

2019/04/11

Hayabusa2 reporter briefing27

6. Future plans
Operation plan
• April 2325 Crater Search Operation (Post-SCI)CRA2
Press and media briefings• April 18 10:3012:00  Opportunities for interviews with thevisiting OSIRIS-REx project members in Japan @ JAXA Sagamihara
Campus.

2019/04/11

Hayabusa2 reporter briefing28Reference material

2019/04/11

Hayabusa2 reporter briefing29

Small Carry-on Impactor operation
SCI operation sequence• SCI separation height is 500m
• From SCI separation to
explosion: about 40 minutes• Return to home position: about
2 weeks+ !)#!#!#* " !#, %!#!#!#-' " #!

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 ""
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2019/04/11

Hayabusa2 reporter briefing/ #$!#
"#

0image credit2JAXA1
30

Small Carry-on Impactor operation    (a)(b)(a) High speed debris(b) High speed ejector(c) Slow speed ejector

Ryugu

(c)

$image credit&JAXA%
2019/04/11

Hayabusa2 reporter briefing!            
  
"       
  
 !#               
                       31

Small Carry-on Impactor operationHP
coordinate
systemSun
Distances approximateHop o me
si t
io n

Earth
Earth
Sun

ion

m





Ryugu

16
km

HP

HP

-Z

-X

Zodiac side






10
0km

Ryugu



4.5
k



1k
m

exp a n s

19km

image creditJAXA
2019/04/11

Hayabusa2 reporter briefing32Small Carry-on Impactor

Selection of impact target point and reason for choice

Impact target point(6.00, 303.00)

Constraint
Target point at a subearth latitude (~6∘N during the SCI collision (predicted collisionarea has a radius of about 200m = latitude / longitude 30 ∘ in 3σ .

S01(5.13, 303.39)

Selection criteria for target points

1st priority Area where a generated crater can be found.
2nd priority

Area which is suitable for landing.

L12→ Flat areas with a layer of sand are desirable.
Collision target point latitude and longitude (6.00 ∘, 303.00 ∘)Flat areas are scattered around the vicinity of the flat region L12 (where the next
touchdown candidate, S01, is located).
Possibility to collect a sample from areas other than TD1 (Horai Fossa and the eastern
hemisphere).
This is a geological area very similar to TD1 and the depth distribution of matter andstructure can be discussed by comparing with the TD1 sample with an excavated sample.

Captured by the ONC-T, hoveringfor MASCOT deployment(approximately 3km altitude)

Image creditJAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute, Meiji University, University of Aizu, AIST.)

2019/04/11

Hayabusa2 reporter briefing

33

Small Carry-on Impactor    
Impact target point(6.00, 303.00)
S01(5.13, 303.39)

L12
Crater generation area              
Image credit JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute, Meiji University, University of Aizu, AIST.)

2019/04/11

Hayabusa2 reporter briefing34

Small Carry-on Impactor
SCISmall Carry-on Impactor
u Shape: conical (diameter 300mmweight 14kg, explosive: ~9.5kg)
u Liner (impactor part): Pure copper 2kg), thickness ~5mm

u Explosive: HMX based PBX (Plastic bonded explosive)!
u Explosive
accelerates liner to 2 km/s in about 1/1000 seconds.
!
!
!

          
2019/04/11

Image creditJAXA

Hayabusa2 reporter briefing   

  
35

Deployable camera
Outline of the deployable camera (DCAM3)• Deployable camera has a cylindrical Φ80 mm # 78 mm
shape, excluding the lens and protruding antenna.
• There are two built-in cameras; one analog camera that cantransmit images in low resolution but in real time, and one
digital camera for digital communication of high resolution
images.
• There is also an analog and digital transmitting antenna forsending images.
• The battery enables imaging and wireless datatransmission for up to 3 hours (depending on conditions).
• Images can be transmitted to the mothership wirelessly
even at distances of 10km or more.
• A small monitor camera (MCAM) is mounted on theseparation mechanism to try and capture images of how
DCAM3 separates and leaves.
2019/04/02

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Hayabusa2 reporter briefing 

$Image credit&JAXA%
36

Deployable camera
Outline of observations from deployable camera(DCAM3)

Near field(Digital system)

Far field(Digital system)• Observe the impact from about 1km distance:- Ryugu- Scattered material generated during the collision- High speed debris (digital only- Low speed dust (digital only- SCI main body before explosion (digital only)(Ogawa et al., Space Sci. Rev. 208, 125-142, 2017)• Analog system: color, viewing angle 71ºx53º,
720x526 pixels, resolution about 10m.
Digital system: Monochrome, viewing angle
74ºx74º, 2000x2000 pixel, resolution about
1m.
• Analog system can send data to the mothership in real time. Digital system is delayed
before sending.
2019/04/02

Sun
about  

SCI

Camera
viewing
direction

DCAM3

about
 1 km





(Radius~ 500m)Hayabusa2 reporter briefing

mother ship37

Crater excavation depth• Depth of the excavation area is about 1/10 of the crater diameter.

Pre- impact

Crater formation

Excavation area
Rt

An example of numerical simulations of crater formation impacts on a
granular layer (sand). Color corresponds to the depth prior to collision.
(Provided by Koji Wada)

Excavation model(Image credit: Chiba Institute of Technology)

2019/04/02

Hayabusa2 reporter briefing

38Ejector seen during collision experimentsboulder

Powder (gravel) layer

Basalt: P=0%

strength

Glass beads (100µm): P=40%

Porosity

Mortar: P=20%

Impact speed: 4km/s
Φ7mm, nylon

2019/04/02

Perlite (3mm): P=80%
Impact speed: 90 m/s
Φ3mm, aluminum

Hayabusa2 reporter briefing

High porosity layer

Plaster: P=50%

Strength

P: PorosityφProjectile diameter

Porous silica dust:
P=65%
Impact speed: 3.2km/s
Φ2mm, nylon

Courtesy of Kobe University
Arakawa Laboratory39

Impactor Experiment Science

To understand the repeated collisional growth and destruction of celestial body evolution•

What kind of collision crater can / cannot form on the surface of Ryugu?
–

•

•

•

Construction of a collision physics model (scaling law) based on the collision experiment in real asteroid material andenvironment.

•

Construction of scaling rules for Ryugu’s collisional history and surface age estimation (crater chronology)
Scaling law: a universal equation connecting collision conditions
and the properties of the formed crater.

What’s going on below Ryugu’s surface?
–

Exposure and collection of subsurface material via crater formation → Assessment of the impact of space weathering andsurface flow.

–

In-situ observation of ejector → Estimate subsurface conditions (porosity, particle size, distribution etc.)

Does Ryugu’s surface move easily?
–•

Observation of the crater formation process and measurements of the formed crater size and shape.

Principal role of DCAM3

Measurement of terrain changes from the impact → Understand the effect of impact vibrations, the presence of few small
craters.

In case we hit a boulder…
–

2019/04/02

Crater on boulder measurement or measurement of fragments from boulder destruction → Estimated strength of asteroid
material
Hayabusa2 reporter briefing

40Thermal infrared camera (TIR
TIR=Thermal Infrared Imager

 Detector
 Observation wavelength Observed temperatures
 Relative accuracy Dimensions
 Viewing angle
 Resolution(© JAXA)
2019/04/02: 2D uncooled bolometer: 8–12 µm: –40 to 150 °C: 0.3 °C
: 328  248 (effective): 16°12°: 20 m (20-km alt.
5 cm (50-m alt.

Large

400

Stone

Gravel

Night

350

Small

Temperature change

Sand

Temp
(K) [K]
Temperature

The surface temperature of the asteroid changes over theday, rising in sunlight and decreasing at night.
Diurnal change in surface temperature is large in finesoils like sand and highly porous rock, and small in denserock.
The physical state of the asteroid’s surface is investigatedby 2D imaging (thermography) of thermal radiation fromthe asteroid.

Night

Day

I=10

300

I=50
I=100

250

I=200

200

I=500

150

I=1000

I=2000

100













Longitude[deg]
Longitude

Hayabusa2 reporter briefing







41
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