presentation tsuda hayabusa2 sbag · 2019. 1. 30. · yuichi tsuda, hayabusa2 project team...
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HHaayyaabbuussaa22 UUppddaattee
Yuichi Tsuda,Hayabusa2 Project Team
Institute of Space and Astronautical ScienceJAXA
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Hayabusa2 MissionHayabusa2 is the 2nd Japanese sample return mission to a small body. JAXA launched Hayabusa2 in 2014 which is now exploring the C-type asteroid Ryugu, and will return back to the Earth in 2020.
• Round-trip mission– High specific impulse ion engine for
continuous-thrust trajectory control.• In-situ science at “Ryugu”
– 1.5year proximity operation at Ryugu– Four landers, four remote science
instruments.• Touch down & sample collection
– Two normal touch down, one pin-point touch down (to an artificial crater) are planned.
• Artificial crater forming– Kinetic impact on the asteroid surface to
create a 2m-class crater.– Investigating Sub-surface structure of the
asteroid2
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Ryugu arrival
3June 27, 2018
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This is Ryugu
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The surface is very dark. The axis of rotation is nearly perpendicular to orbital plane.Features include craters, numerous boulders (including rocks up to 130m in size)
and a grooved terrain.
UTC 2018-06-26 03:50
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Scientific Features of Ryugu
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• Top shape with a very circular equatorial bulge• Radius: mean 450 m
equatorial 500 m polar 440 m• Mass: 450 million ton GM 30 m3s-2 )• Rotation axis: (λ, β) = (180 , -87 ) • Obliquity: 8• Rotation period P = 7.63 hours• Reflectance factor v-band 0.02• Crater number density: as much as those on Itokawa and Eros• Many boulders: the largest near the south pole is ~130 m across• Optical spectra: flat spectra, bluer in equatorial bulge and poles• NIR spectra: uniform flat (slightly redder) spectra with weak water absorption• brightness temperature strong roughness effect (flat diurnal Temperature
variation), higher thermal inertia in the equatorial bulgeThe gravity at the equator is eighty-thousandth of the Earth and a few times of
Itokawa)
©JAXA University of Tokyo & collaborators
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Approved Names on Ryugu
6Theme: names from children’s stories
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“Landing Site Selection”
• Held on August 17, 2018• 109 participants including DLR/CNES/NASA.• Three s/c landing sites (1 primary, 2 backups), MINERVA-II-1 site, MASCOT site
were selected based on safety and scientific value.
7©JAXA
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“Landing Site Selection”
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Touch-Down site analysis MINERVA site analysis MASCOT site analysis
MASCOTHayabusa2
MINERVA-II1
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MINERVA-II-1 Operation
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2018
Sep 20
04:08 Gate1 Decision (Descent Start = Go)
05:08 Altitude 20km, Descent rate -0.4m/s
15:46 Gate2 Decision (5km Check-point = GO) Descent rate -0.1m/s
Sep 21
01:17 Rover Power On
03:25 Gate3 Decision (Spacecraft autonomous & rover sepration = Go)
04:06 Rover Separation
04:07 Ascent Delta-V, Ascent rate = +0.4m/s
04:11 TX Switched to LGA-A (for scanning observation maneuver)
04:28 Gate4 Decision (Ascent confirmation = Confirmed)
04:47 TX Switched to HGA (Back to Earth pointing attitude)
05:05 Gate5 Decision (Scan sequence completion = Confirmed)
05:36 HP return Delta-V
06:36 Gate6 Decision (HP return confirmation = Confirmed)
(5) MINERVA separation
Time
Altitude
HP:20 [km]
Separation Altitude 50 ~
55m(TBD)
(Not to Scale)
(Not to Scale)
(1) GCP-NAV
(2) GCP-NAV altitude control off(3) FF ΔV to decelerate descent
velocity
free fall
[Event]
Trigger Altitude:60 [m] (TBD)
(4) Wait for attitude control convergence
constant descent velocity e.g. 10 [cm/s]
(7) Ascent ΔV
Ascent Altitude30 + β [m] (TBD)
Point A:MINERVA Separation
Point B:1st Contact on Surface
(9) MINERVA landing
(8) Attitude scan
ONC-W1
ONC-T
ONC-W2
(10) HP Keeping
(6) Additional free fall for preventing plume contamination
Point C:Final settlement Point
Candidate of Simulation Epoch
at LIDAR Alt. 60m“Lateral dV1 (Before
Separation) ”“GCP-NAV end”
After 350sec of “Lateral dV2 (After
Separation)”
HP: Home Position
↓↓
↓
↓
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Surface Exploration by MINERVA-II1
Image credit JAXA
Two rovers hopped, collected data, and constantly sent data back to the spacecraft.
Two MINERVA-II-1 rovers have become the world first robots which successfully performed mobile activity on the small body surface.
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Image captured by Rover-1A on September 22 at around 11:44 JST. Color image captured while moving (during a hop) on the surface of Ryugu. The left-half of the image is the asteroid surface. The bright white region is due to sunlight. (Image credit: JAXA).
MINERVA-II1 imagesInitial images from falling and hopping rover
Image captured by Rover-1A on September 21 at around 13:08 JST. This is a color image taken immediately after separation from the spacecraft. Hayabusa2 is at the top and the surface of Ryugu is bottom. The image is blurred because the shot was taken while the rover was rotating.
Image credit JAXA Image credit JAXA
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Sep 23, 2018, before hop of Rover-1B
MINERVA-II1 images
Images credit JAXA
pin
antenna
Sep 23, 2018, Rover-1A on surface
Sep 23, 2018, Rover-1A on surface with self shadow
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15 frames captured on September 23, 2018 from 10:34 – 11:48 JST
MINERVA-II1 movie
credit JAXA
Scenery of Ryugu surface observed by Rover-1B
animation
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MINERVA-II-1 Result
• Separation: Sep 21 04:06UT.• MINERVA-II-1A: – Last telemetry reception was on Oct 26 (113 sol)–Weak carrier signal had been received until recently.
• MINERVA-II-1B: – Last telemetry reception was on Sep 24 (10 sol)–Weak carrier signal had been received until recently.
World first robots which performed mobile activity on the small body surface!
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MASCOT Operation
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Oct 201:50 Gate1 Decision (Descent Start = Go)02:50 Altitude 20km, Descent rate -0.4m/s13:29 Gate2 Decision (5km Check-point = GO) Descent rate -0.1m/s23:48 MASCOT Final ConfigurationOct 300:50 Gate3 Decision (Spacecraft autonomous & lander separation = Go)01:57 MASCOT Separation01:59 Ascent Delta-V, Ascent rate = +0.4m/s02:03 TX Switched to LGA-A (for scanning observation maneuver)02:21 Gate4 Decision (MASCOT sep & Ascent confirmation = Confirmed)02:40 TX Switched to HGA (Back to Earth pointing attitude)02:58 Gate5 Decision (Scan sequence completion = Confirmed)05:29 Arrival at 3km Hovering altitude06:29 Gate6 Decision (Low-Alt hovering = GO)19:30 Mission Completion Announcement by MASCOT project teamOct 411:30 Home Position Return delta-V +0.3m/s
↓↓ ↓ ↓
↓
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MASCOT Operation Result
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Sol1• MASCOT separated.• Settled on ground with the upside-
down orientation.• Observation executed at night.Sol2• A “big hop” commanded from ground
to flip the MASCOT orientation.• Observation executed at night.Sol3• Small relocation hop commanded
from ground to change camera and microscopic spectrometer FOVs.
• Fall into power save mode.• Final data downlink.• Battery depleted after 17 hrs of on-
surface operation.
CNES (Toulouse) DLR (Cologne)
JAXA/SSOC(Sagamihara Space Operation Center)
JAXA UDSC(Usuda Deep Space Center)
NASA DSN(Deep Space Network)
ESA ESTRACK(ESA Tracking
Station Network)
300 million km
Hayabusa2(Relay)
MASCOT
Largest lander on Ryugu.Perfectly successful collaboration among DLR/CNES/NASA/ESA/JAXA.
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Images by MASCOT
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Oct. 3, 2018, During free fall Oct. 3, 2018, Right before initial bounce
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Increased Accessibility to Surface
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MINERVA-II1 Descent
MASCOT Descent
TD1-R1A, TD1-R3
Low Altitude (
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Decided Landing Sites and Accomplishments
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LSS Decision Meeting on Aug 17, 2018Touchdown L08 backup L07, M04 To be conducted next year!MASCOT MA-9 Landed on Oct.3!MINERVA-II-1 N6 Landed on Sep.21!
MINIERVA-II-1 SeparationAccuracy 3.3m, +50s
MASCOT SeprationAccuracy 30m, -60s
TD1-R1-A Touch Down RehearsalAccuracy10.8m, -55sec
TD1-R3 TM Release)Accuracy15.4m, -64sec
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Candidate Landing Zone L08-B
100m
L08-B
L08-B
6m
20m
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Toward Spacecraft’s Touch Down
• The original design assumes TD accuracy of 50m.• L08 area (100x100m width) has been selected as the
target landing site in the LSS decision meeting on Aug.17.• Further observations revealed that there is only
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Touch Down (Rehearsal) Sequence
25m
20m
0m
Key technology of TD
GNC accuracy
Terrain safety
LRF performance
TM tracking control reliability
TD operation
TD Rehearsal on
Oct.25, 2018
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Target Maker has landed!
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L08-B
TD1-R3 ONC-W1 image
TM1
10m
15m
5m
Only 15.4m off from L08-B center.
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TM autonomous tracking in TD1-R3 (with Target Control Box)
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CAM-H movie in TD1-R3
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Touch Down Target
TM
15 m
L08-B
12m
6m
L08-B1Area
L08-E1 Area
L08-B1
L08-E1TM
Wider but farther from TM
Narrower but closer to TM
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Touch Down Operation is scheduled in the week of Feb.18 (Feb.18-24)
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Mission Accomplishments
Ryugu ArrivalCharacterization of Ryugu, Mapping, Gravity Measurement.Delivering Two MINERVA-II1 Rovers to Asteroid SurfaceDelivering MASCOT Lander to Asteroid SurfaceSpacecraft Touch-DownCrater FormingSpacecraft Touch-Down to Crater* (if situation allows)Delivering MINERVA-II2 Rovers to Asteroid SurfaceEarth Return
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Thank you
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