TopicsMINERVA-Ⅱ1 Schedule for deployment

The mission operation to deploy the MINERVA-Ⅱ1 rovers will be conducted from September 19 – 21. On September 19, activities will focus on preparation for the spacecraft to descend towards asteroid Ryugu and on September 20, the actual descent will begin. The scheduled deployment of the MINERVA-Ⅱ1 rovers is on September 21.

The approximate schedule currently planned is shown in the following table. The safety of the spacecraft is a priority in all operations, so the schedule may change depending on the current situation.

MINERVA-Ⅱ1 main schedule for deployment
Date & Time(UTC)Date & Time(JST)Spacecraft speed (cm/s)HP altitude (m)Near-point altitude (m)Event
9/19 00:009/19 09:0020,000Communication via Usuda Deep Space Center begins
9/19 08:109/19 17:10Communication via Madrid DSN begins
9/19 16:009/20 01:00Comm. via Goldstone DSN begins
9/20 00:009/20 09:00Comm. via Usuda begins
9/20 04:109/20 13:10confirm readiness for descent
9/20 05:109/20 14:10-4020,000Begin descent
9/20 07:109/20 16:10Comm. via Canberra DSN begins
9/20 08:109/20 17:10Comm. via Madrid DNS begins
9/20 10:009/20 19:0013,000
9/20 15:309/21 00:30-105,000Decelerate descent speed ΔV
9/20 16:009/21 01:00Comm. via Goldstone DSN begins
9/20 18:309/21 03:304,000
9/21 00:009/21 09:00Comm. via Usuda begins
9/21 00:009/21 09:002,000
9/21 00:109/21 09:101,500
9/21 03:009/21 12:00500
9/21 03:409/21 12:40250
9/21 04:00
9/21 13:00
~60MINERVA deployment
9/21 04:00
9/21 13:00
+50~60Post deployment upward ΔV
9/21 05:409/21 14:40TBDIncrease ΔV to return to home position
9/21 07:209/21 16:20Comm. via Canberra DSN begins
9/21 08:109/21 17:10Comm. via Madrid DSN begins
9/21 16:009/22 01:00Comm. via Goldstone DSN begins
9/22 00:009/22 09:00Comm. via Usuda begins
  • Time: Approximate schedule time (in 10 -minute 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 18 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.

Operation sequence
  • dV, ΔV:acceleration of the spacecraft
  • free fall:The speed of the spacecraft is not controlled, but falls due to the pull of Ryugu’s gravity.
  • GCP-NAV:Ground Control Point Navigation, tool for image guided navigation during the descent operation.
  • HP:home position
  • LIDAR:laser altimeter
  • ONC-T:Optical Navigation Camera Telescopic (installed on the bottom of the spacecraft).
  • ONC-W1:Optical Navigation Camera Wide angle (installed on the bottom of the spacecraft).
  • ONC-W2: Optical Navigation Camera Wide angle (installed on the side of the spacecraft).
  • Attitude scan:change the attitude of the probe to photograph MINERVA-Ⅱ1
  • constant descent velocity: the spacecraft descends at a nearly constant speed. At first, this speed is about 40 cm/s. From an altitude of about 5km, the speed is about 10 cm/s.
  • Trigger Altitude:when this altitude is reached, the spacecraft’s speed will be controlled.
  • Additional free fall for preventing plume contamination: the spacecraft will not use thrusters during the period shown in the figure when MINERVA-II1 is in free fall. This is to avoid thruster gas hitting MINERVA-II1.

Hayabusa2 project