The first touchdown by Hayabusa2 to collect samples from the asteroid surface is planned for the end of October. The first rehearsal for this operation will be held from September 10 – 12. “Touchdown 1 Rehearsal 1” is abbreviated to TD1-R1. At TD1-R1, the Hayabusa2 will approach the surface of Ryugu to an altitude of less than 40 m. The spacecraft will then rise without landing. The purpose of this rehearsal is to monitor the operation of the spacecraft during touchdown and investigate the safety of the touchdown candidate sites by imaging the surface of Ryugu in their vicinity from a low altitude. The schedule for the TD1-R1 operation is shown in the table below. The actual operation will occur while assessing the situation at that time, so do note that procedures may not always be on schedule.
Touchdown 1 Rehearsal 1（TD1-R1）main schedule
|Date & Time（UTC）||Date & Time（JST）||Spacecraft speed (cm/s)||HP altitude (m)||Near-point altitude (m)||Event|
|9/10 00:00||9/10 09:00||0||20,000||Communication via Usuda Deep Space Center|
|9/10 08:30||9/10 17:30||Communication via Madrid DSN begins|
|9/10 15:55||9/11 00:55||Comm. via Goldstone DSN|
|9/11 00:00||9/11 09:00||Comm. via Usuda Deep Space Center|
|9/11 05:25||9/11 14:25||Gate1 confirmation (confirmation before start of descent)|
|9/11 06:25||9/11 15:25||-40||20,000||Descent begins|
|9/11 08:30||9/11 17:30||Comm. via Madrid DSN|
|9/11 11:15||9/11 20:15||13,000|
|9/11 15:55||9/12 00:55||Comm. via Goldstone DSN|
|9/11 16:45||9/12 01:45||-10||5,000||Decelerate descent speed ΔV|
|9/11 17:05||9/12 02:05||Gate2 confirmation (descent deceleration ΔV confirmation)|
|9/11 19:45||9/12 04:45||4,000|
|9/11 23:55||9/12 08:55||Comm. via Usuda Deep Space Center|
|9/12 01:20||9/12 10:20||2,000|
|9/12 02:50||9/12 11:50||1,000|
|9/12 04:15||9/12 13:15||500|
|9/12 04:15||9/12 13:15||Gate3 confirmation|
|9/12 05:25||9/12 14:25||below 40m||Reach target altitude|
|9/12 05:25||9/12 14:25||+70||Withdraw ΔV|
|9/12 05:50||9/12 14:50||Gate5 confirmation（soundness check）|
|9/12 06:40||9/12 15:40||Gate6 confirmation（confirmation of ΔV in order to return to home position）|
|9/12 07:40||9/12 16:40||6,000||Home Position return confirmed viaΔV measurement.|
|9/12 08:30||9/12 17:30||Comm. via Madrid DSN|
|9/12 15:55||9/13 00:55||Comm. via Goldstone DSN|
- Time: Approximate schedule time (in 5-minute increments). There is a possibility that this may change during operation. The time is the onboard time, so confirmation of the event is the radiowave propagation time of about 17 minutes later.
- Spacecraft speed: This is the speed relative to the asteroid (minus is towards the asteroid, positive is away). Numerical value is displayed only when speed control is performed. After a speed control operation, the speed changes due to the gravitational force of Ryugu and other celestial bodies.
- HP altitude：Distance to the center of Ryugu
- Near point altitude：Distance to the surface of Ryugu.
- Gate: These are operation checkpoints where it is judged whether to proceed on the basis of the situation of the spacecraft and ground station.