Akatsuki

Akatsuki

Spacecraft· JAXAcompleted

Akatsuki — Japan's Venus Climate Orbiter. After its first orbit insertion failed in 2010, JAXA recovered the craft and, on a second attempt five years later, made it the first Japanese spacecraft to orbit another planet — studying Venus's super-rotating atmosphere until contact was lost in 2024 (mission formally ended 2025).

Open in 3D viewSee Akatsuki in the live, interactive 3D map

Key facts

Current speed
35.1 km/s
Distance from Sun
0.721 AU
Status
Completed
Launched
2010

Mission & specifications

Mission

Operator
JAXA
Launched
May 20, 2010
Status
Completed

Trajectory

Current speed
35.1 km/s
Distance from the Sun
0.721 AU
Distance from Earth
1.33 AU
Distance from Mercury
0.555 AU

Mission

Akatsuki — Japanese for 'dawn' — is Japan's mission to Venus, and a story of a second chance. Built to study the planet's bizarre, super-fast atmosphere, it reached Venus in December 2010 and fired its main engine to slip into orbit — but the engine failed catastrophically mid-burn, a fuel valve having jammed, and the spacecraft sailed straight past the planet into orbit around the Sun. Most missions would have been written off. Instead, JAXA engineers nursed the wounded craft for five years, dumping oxidiser to lighten it and planning an audacious recovery. In December 2015, using only its small attitude-control thrusters, Akatsuki caught up with Venus again and, on its second attempt, finally entered orbit — the first Japanese spacecraft to orbit another planet. From orbit it watched Venus's atmosphere, which whirls around the planet far faster than Venus itself rotates — a phenomenon called super-rotation that is still not fully understood. Its infrared and ultraviolet cameras tracked towering cloud patterns, including a vast, stationary bow-shaped wave thousands of kilometres long, and probed the structure of the hurricane-force winds through a primary mission (2016-2018) and years of extended observations. Contact was lost in April 2024, and JAXA formally ended the mission in September 2025 — but Akatsuki had already turned a near-total failure into one of the most resilient planetary missions ever flown.

  1. 2010Launch toward VenusLaunch

    Japan's Venus Climate Orbiter sets out.

  2. 2010Orbit insertion failsMilestone

    The main engine fails mid-burn; Akatsuki flies past Venus into orbit around the Sun.

  3. 2015A second chance at VenusArrival

    Using only its small thrusters, Akatsuki finally enters Venus orbit, five years later.

  4. 2016Mapping super-rotationMilestone

    Tracks a planet-wide stationary bow wave and the hurricane winds of Venus's atmosphere.

  5. 2024Contact lostMilestone

    After a primary and long extended mission, Akatsuki falls silent in April 2024.

  6. 2025Mission concludedMission end

    JAXA formally ends the mission; the orbiter drifts on, silent, around Venus.

Images

Akatsuki, Japan's Venus Climate Orbiter
JAXA / ISAS (CC BY 4.0) · Wikimedia Commons

Images from open archives · credit shown per image