Akatsuki

Chronology

Mission timeline

1. May 20, 2010, 21:58:22 UTC

   Launch

   Launched on an H-IIA from the Tanegashima Space Center

   The master catalog records that Akatsuki launched on an H-IIA rocket on 20 May 2010 at 21:58:22 UTC (21 May, 6:58:22 a.m. JST) from the Tanegashima launch center, that the spacecraft separated from the booster 27 minutes after liftoff and went into an Earth phasing orbit and was then put into a Venus transfer orbit, and that a small solar power sail demonstration mission, Ikaros, was also launched on the H-IIA rocket. The launch/orbital information page prints the same instant. JAXA's project page dates the launch in Japan Standard Time, printing Launch Date 6:58, May 21, 2010 (JST) and Launch Vehicle H-IIA Launch Vehicle No.17; the record carries the UTC instant NSSDCA prints and records the JST date rather than converting between them.

   Earth
2. December 7, 2010

   Flyby

   First Venus orbit insertion fails and the spacecraft flies past the planet

   JAXA's project page records that JAXA attempted to insert the orbiter into the orbit circling around Venus on Dec. 7, 2010, but it failed as the main engine for orbit control was broken. The master catalog gives the sequence: the orbital insertion rocket firing began at 8:49 a.m. JST and was scheduled to finish 12 minutes later, ignition was confirmed before Akatsuki passed behind Venus for 22 minutes, communications were not regained on schedule at 00:12 UT and signals were finally received at 01:28 UT, and a faulty valve in the fuel pressure system meant the engine firing scheduled for 9 minutes, 20 seconds only lasted about 152 seconds, so the spacecraft did not enter Venus orbit but instead flew by the planet.

   Venus
3. December 7, 2015

   Orbit insertion

   Second attempt puts Akatsuki into Venus orbit

   JAXA's project page records that on Dec. 7, 2015, JAXA successfully inserted the orbiter into the Venus orbit by emitting thrust from the attitude control engine, and that the orbit would be shifted to an elliptical orbit whose period is about nine days. The master catalog records that the orbit from the new encounter is an approximately 10 day orbit with a 360,000 km apoapsis and a periapsis varying between 1,000 km and 10,000 km in altitude, against the near equatorial 30 hour orbit with an apoapsis of about 79 000 km originally planned. THE THREE PAGES DIFFER IN PRECISION RATHER THAN IN VALUE, WHICH IS WHY THE SEGMENT AUDIT DOES NOT COUNT IT AS A DISAGREEMENT: JAXA's operation-completed release says the spacecraft successfully entered Venus orbit in December 2015, the project page prints Dec. 7, 2015, and the master catalog prints putting it into orbit on December 7. The day is committed because two of the three print it.

   Venus
4. May 2016

   Milestone

   Systematic scientific operations begin

   The master catalog records that after 5 months of check-outs, systematic scientific operations began in May, 2016. JAXA's project page, written before the fact, says full-scale observations are scheduled to begin in April 2016; the record follows the month NSSDCA prints for what happened and carries the plan as a disagreement.

   Venus
5. December 9, 2016

   Milestone

   The near-infrared cameras fail

   The master catalog records that the near-infrared (1 and 2 micron) cameras failed on 9 December 2016, and that in April 2018 Akatsuki finished its nominal science mission and entered an extended mission.

   Venus
6. April 2024

   Loss of contact

   Communication lost near the end of April 2024

   JAXA's operation-completed release records that communication with Akatsuki was lost during operations near the end of April 2024, triggered by an incident in a control mode of lower-precision attitude maintenance for a prolonged period, and that although recovery operations were conducted to restore communication, there has been no luck so far. The master catalog says the spacecraft was operating and returning data until contact was lost in late April, 2024. Carried at month precision because neither page prints a day.

   Venus
7. September 18, 2025

   Mission end

   JAXA terminates operations

   JAXA's press release records that the Japan Aerospace Exploration Agency conducted the termination procedure for the Venus Climate Orbiter Akatsuki starting at 9:00 AM on September 18, 2025 (JST), thereby ending the probe's operations, and that considering the fact that the spacecraft has aged, well exceeding its designed lifetime, and was already in the late-stage operation phase, it has been decided to terminate operations. Carried at the day the release prints, which is a Japan Standard Time date. THE NSSDCA PAGE DOES NOT KNOW THIS: the capture cited here predates the release and still says JAXA is continuing to attempt to reestablish communication with the spacecraft.

   Venus

Mission architecture

Vehicles

• Akatsuki · Orbiter · completed

  Destinations: Venus