#As­ter­oid­Land­ing in Aus­tralia – the land­ing of the Hayabusa2 sam­ple-re­turn cap­sule

The terminal guidance phase
The ter­mi­nal guid­ance phase
Image 1/2, Credit: JAXA, adapted by DLR

The terminal guidance phase

The Hayabusa2 space­craft had to per­form five tra­jec­to­ry cor­rec­tion ma­noeu­vres (TCMs) to suc­cess­ful­ly com­plete its mis­sion. Whilst the cap­sule car­ry­ing the sam­ples from as­ter­oid Ryugu will land safe­ly on Earth, Hayabusa2 will move on to chart a new course through space.
Return cruise of Hayabusa2
Re­turn cruise of Hayabusa2
Image 2/2, Credit: JAXA, adapted by DLR

Return cruise of Hayabusa2

Or­bit map of the re­turn cruise of the Hayabusa2 space­craft af­ter de­part­ing from as­ter­oid Ryugu in Novem­ber 2019.

On 17 September 2020, the Hayabusa2 mission entered a crucial phase – returning samples from asteroid Ryugu to Earth. Upon reaching a distance of 36 million kilometres from Earth, the spacecraft used its ion propulsion system to move into a distant orbit around our planet. It then had to perform five trajectory correction manoeuvres (TCMs) to successfully complete its mission. Whilst the capsule carrying the samples from Ryugu will land safely on Earth, Hayabusa2 will move on to chart a new course through space.

The first of the five TCMs was successfully completed on 22 October 2020, at a distance of some 17 million kilometres from Earth. The spacecraft's chemical thrusters were used for this and the subsequent TCMs. The next TCM was also successful; at a distance of nine million kilometres from Earth, the spacecraft made another fine adjustment to its course on 12 November 2020.

Approaching Earth

Once Hayabusa2 reached 3.5 million kilometres from Earth on 26 November 2020, the spacecraft shifted to a new trajectory that is aligned with the landing site near Woomera, Australia (at approximately 31 degrees south and 136 degrees east). This change of course set the re-entry trajectory for the capsule. The final correction to the spacecraft trajectory will be performed on 1 December 2020, when Hayabusa2 is about 1.8 million kilometres from Earth.

The separation of the landing capsule from the spacecraft is scheduled for 5 December 2020 between 06:00 and 07:00 CET, at a distance of approximately 200,000 kilometres from Earth; this is just over half the distance between Earth and the Moon. Shortly afterwards (between 07:00 and 09:00 CET), Hayabusa2 will perform its final manoeuvre to depart from this trajectory – otherwise, the spacecraft would also enter Earth’s atmosphere. This is not the plan; instead, the new trajectory will take Hayabusa2 back out into space for a new asteroid mission.

As soon as the sample capsule – rotating slowly around its axis – enters Earth’s atmosphere at a speed of twelve kilometres per second and an altitude of 120 kilometres, it will be slowed down by the atmosphere. Seven to eleven kilometres above Australia, between 18:30 and 18:33 CET, a parachute will be deployed then the heat shield in front will be ejected. The 40-centimetre capsule will land at the Woomera Test Range between 18:47 and 18:57 CET on 5 December 2020. This is between 02:47 and 02:57 JST (Japan Standard Time) or 05:17 am and 05:27 local (summer) time in Woomera on 6 December 2020 – shortly before sunrise. During the parachute flight, signals will already be transmitted to help a recovery team locate the 16-kilogram capsule. The team will then fly over the landing area in a helicopter to find the capsule using the locating signals and recover it in a complex procedure.

Hayabusa2 – timetable for Earth approach, course manoeuvres, capsule separation and landing

Event

Objective

Date and time (Japan)

Date and time (CET)

Distance from Earth

Components

TCM-3

Trajectory correction approaching Earth

26 November

16:00–17:00

26 November

08:00–09:00

3.6 million km

Hayabusa2

TCM-4

Correction orbit approaching Earth

1 December

16:00

1 December

08:00

1.74 million km

Hayabusa2

Separation of sample capsule

Sample capsule on ballistic course

5 December

14:30

5 December

06:30

220,000 km

Hayabusa2

Sample capsule

TCM-5

New course for Hayabusa2

5 December

15:30–18:00

5 December

07:30–10:00

200,000–160,000 km

Hayabusa2

Earth shadow

Hayabusa2 enters Earth’s shadow

6 December

01:57

5 December

17:57

12,000 km

Hayabusa2

Sample capsule imaging

Hayabusa2 acquires images of sample capsule

6 December

02:28–02:30

5 December

18:28–18:30

700–300 km

Hayabusa2

Entering the atmosphere

Entry into Earth’s atmosphere at 12 km/s

6 December

02:28–02:29

5 December

18:28–18:29

120 km

Sample capsule

Earth shadow (end)

Hayabusa2 leaves Earth’s shadow

6 December

02:31

5 December

18:31

350 km

Hayabusa2

Parachute

Release of brake parachute

6 December

02:31–01:33

5 December

18:31–18:33

11–7 km

Sample capsule

Landing

Sample capsule lands in Woomera (AUS)

6 December

02:47–02:51

5 December

18:47–18:51

0 km

Sample capsule


Next stop – a 'fast rotator'

During its Earth flyby, Hayabusa2 will have approximately half the xenon propellant for its ion engines still available, and thus the opportunity to embark upon an extended mission. The Japan Aerospace Exploration Agency (JAXA) has selected the small asteroid 1998 KY26 as its target. This asteroid measures just 30 metres across and because it spins extremely quickly, it is referred to as a 'fast rotator'. No object with these characteristics has ever been visited by humanity. The scientists expect that their comparative observations will enhance the findings that have been gained from the Hayabusa2 mission. The extended mission is a long-term venture; the spacecraft is expected to reach its target asteroid in 2031.

Contact
  • Elke Heinemann
    Ger­man Aerospace Cen­ter (DLR)
    Pub­lic Af­fairs and Com­mu­ni­ca­tions
    Telephone: +49 2203 601-2867
    Fax: +49 2203 601-3249

    Contact
  • Tra-Mi Ho
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Space Sys­tems
    Telephone: +49 421 24420-1171
    Robert-Hooke-Straße 7
    28359 Bremen
    Contact
  • Ulrich Köhler
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
    Rutherfordstraße 2
    12489 Berlin
    Contact
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