Akatsuki Update

Back in 2010, we were sad to hear that JAXA’s Akatsuki orbiter experienced a malfunction during its attempt to insert itself into orbit around Venus. A planned twelve minute engine burn ended prematurely after about only three minutes, the result of salt formation causing a fault in a check valve. You might expect that that would have spelled the end to the mission, and Akatsuki would have spent eternity orbiting the Sun. Fortunately, JAXA would get a second chance to try their insertion effort again, but they’d have to wait nearly five years for both the craft and Venus to be in the right places for the attempt.

Akatsuki - Planet-C

Planet-C Akatsuki

Orbit control test and maneuvers were conducted in 2011, and then again in 2015, setting the stage for an orbit insertion attempt. Tests showed that Akatsuki’s Orbital Maneuver Engine (OME), its main engine, couldn’t provide the thrust needed for the second insertion attempt. Hope fell to the craft’s attitude-adjustment engines.

65 kg of oxidizer fuel that would have been used by the no-longer-functional main engine was dumped to lighten the craft and allow it to be more maneuverable. In December, 2015, exactly five years after the first attempt to make orbit, four of the spacecraft’s secondary attitude control thrusters burned for 20 minutes and 33 seconds, slowing the spacecraft enough to be captured by Venus’s gravitational hold. The attempt was a success. Akatsuki entered Venusian orbit and began to conduct its mission objectives.

The final orbit is much further (between 4,000 km and 370,000 km versus the planned 300 km to 80,00 km) from our sister planet than originally planned. Instead of orbiting Venus once every 30 hours, Akatsuki orbits once every 9 days.

Diagram showing Akatuski's planned and actual orbits

Diagram showing Akatuski’s planned and actual orbits – Credit: JAXA/Nature

So, while not exactly as planned, Akatsuki is still able to conduct great science. Akatsuki has already observed an interesting atmospheric gravity wave, peered through the clouds in infrared to reveal an equatorial jet, and sent back stunning images of our closest planetary neighbor.

False color image of cloud patterns on the night side of Venus taken by the Akatsuki's IR2 camera. Thicker clouds are expressed as darker because thick clouds hamper infrared lights coming from the lower layer of the atmosphere.

False color image of cloud patterns on the night side of Venus taken by the Akatsuki’s IR2 camera. Thicker clouds are expressed as darker because thick clouds hamper infrared lights coming from the lower layer of the atmosphere.  – Source: JAXA/PLANET-C Project Team

You can stay up-to-date with Akatsuki at JAXA’s English language version of their project page.

Akatsuki Fails Venus Orbit Attempt – Oh Well, We’ll Try Again… In Five Years

Akatsuki - Planet-C

Planet-C Akatsuki | Image credit: Akihiro Ikeshita and JAXA

JAXA’s (Japan Aerospace Exploration Agency) third planetary explorer, Planet C (Akatsuki), failed to enter Venus’ orbit following a journey that lifted off in May of this year.

According to JAXA:

The Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency (ISAS/JAXA) performed Venus orbit insertion maneuver (VOI-1) for the Venus Climate Orbiter “AKATSUKI” at 8:49 a.m. on December 7 (Japan Standard Time,) but, unfortunately, we have found that the orbiter was not injected into the planned orbit as a result of orbit estimation.


JAXA has set up an investigation team to try and understand why the orbit insertion failed. While control has been reestablished, “the spacecraft is functioning but has put itself in a standby mode with its solar panels facing towards the Sun. It is also spinning slowly — about every 10 minutes — and radio contact is possible only for 40 seconds at a time.

If control is able to be completely regained, there will be an opportunity to re-try entering Venusian orbit in five years — Akatsuki doesn’t have the fuel to hit the brakes and go back for another go at it.

This will mark the second JAXA planetary explorer that failed to complete its mission. Planet-B — dubbed “Nozomi” — failed to enter Mars orbit in 2003. That mission was abandoned, but the spacecraft is currently still active.

While the challenges of space travel have proven frustrating for JAXA, the agency cannot be said to not have its successes. Planet-A (“Suisei”) came within 151,000km of Halley’s Comet in 1986, as part of an international armada of probes sent to the renowned iceball during its last approach to our neck of the solar system.


Planet-A | Suisei



In addition to that, they have another very nifty, and successful, vehicle out there named IKAROS (“Interplanetary Kite-craft Accelerated by Radiation Of the Sun”). IKAROS is an experiment designed to demonstrate solar-sail technology as a means of traveling interplanetary space. IKAROS is an exciting little machine and I intend to devote an entire post to it in the near future.

Space exploration has come a long way in a very short amount of time, but we continually have these pesky failures to continually remind us that it is also very challenging. As frustrating as these complications may be, we can still appreciate the lessons learned and apply them to the success of future endeavors.