NASA-JAXA Science Cooperation Remains Solid Despite Hitomi Setback – UPDATE

Japan Aerospace Exploration Agency (JAXA) and NASA officials highlighted their decades of cooperation in space science and opportunities for the future at a day-long symposium on Friday.  The long-planned meeting sponsored by the Japan Society for the Promotion of Science also provided an opportunity for the head of Japan’s Institute of Space and Astronautical Science (ISAS), part of JAXA, to explain the recent failure of the Astro-H (Hitomi) x-ray astronomy satellite, a joint JAXA-NASA mission. 

ISAS Director General Saku Tsuneta said the Hitomi failure was the result of two different design problems and one improper operational procedure all related to the attitude control/safe-hold system.  He said the failure was “embarrassing, but a fact” and his priorities now are to fix the problems, recover Hitomi science, and maintain partnerships with NASA and other space agencies.  In response to a question, he stressed that although an individual made a mistake, that person should not be blamed because the system should not have been designed such that a single human error could have catastrophic consequences. [UPDATE: On June 15, JAXA announced that Tsuneta, JAXA President Naoki Okumura, and JAXA Senior Vice President Mamoru Endo each “decided to take a 10% pay cut to their monthly salary for four months” because of the Hitomi failure.]

An English-language powerpoint summary of the failure investigation report is available on JAXA’s website.

Hitomi failed before the operational science period began, but Tsuneta said some data were obtained on the Perseus cluster during initial operations and the cryogenic soft x-ray spectrometer (SXS) worked perfectly.  SXS was developed jointly by ISAS and NASA’s Goddard Space Flight Center (GSFC).

Tsuneta and Geoff Yoder, acting Associate Administrator for NASA’s Science Mission Directorate (SMD), said they had just held preliminary discussions on options for getting the science data that Hitomi was intended to collect, but it is too early for decisions to be made.  Tsuneta was remorseful about Hitomi’s loss.  “JAXA led Hitomi on behalf of the global science community.  That is why this particular disaster is a severe blow to astrophysics. … JAXA has to start something to recover the science of SXS, but this is the result of very deep cooperation between NASA and JAXA.  One nation cannot do [it alone].  So I hope JAXA and NASA can work together to make it happen.” 

NASA/GSFC’s Richard Kelley, the U.S. principal investigator for SXS, discussed the Perseus cluster observations later in the day and noted that if a decision is made to perform a recovery mission, there is spare hardware for key components of SXS.

Both agencies have a full plate of space science missions already on their dockets, so adding a new mission to replace Hitomi would be difficult to achieve.  The next planned x-ray astronomy satellite is the European Space Agency’s  (ESA’s) ATHENA, scheduled for launch in 2028.  

NASA’s Chandra “great observatory” is the flagship spacecraft available today for x-ray astronomy.  X-rays do not penetrate Earth’s atmosphere, so this field of research requires space-based instruments.  Chandra, once known as the Advanced X-Ray Astronomy Facility (AXAF), was launched in 1999 and was just approved for another two-years of operation.  It is operated for NASA by the Smithsonian Astrophysical Observatory.  (The AXAF program actually was split in two because of cost growth. Chandra was the half that was built.  SXS was intended to do the science envisioned for the other half.)

JAXA and NASA cooperate on a wide range of space science missions, including heliophysics and planetary exploration (in addition to earth science and human spaceflight).   One current highlight is cooperation on robotic asteroid sample return missions.  JAXA returned a small sample from the asteroid Itokawa in 2010 and launched a follow-on mission, Hayabusa2, in 2014.  NASA will launch its OSIRIS-REx mission this September.  

Dante Lauretta (University of Arizona), principal investigator for OSIRIS-REx, and Tomoki Nakamura (Tohoku University) and Hitoshi Kuninaka (ISAS), representing Hayabusa2, explained that the two missions are very risky and serve as each others backup. The two teams have agreed to share whatever samples are returned, so if one does not succeed, both teams will still have samples to analyze. Hayabusa2 will arrive at the asteroid Ryugu in June/July 2018 and return its sample to Earth in 2020.  OSIRIS-Rex will arrive at the asteroid Bennu in August 2018 and return its sample to Earth in 2023. Lauretta joked that it was like jumping off a cliff and JAXA gets to go first.

A new mission JAXA is considering would send a probe to return a sample from the Martian moon Phobos.  The Martian Moons eXplorer (MMX) mission is one of two “top priorities” for future JAXA science missions, Tsuneta said. (The other is the SPICA space infrared telescope).  The concept is for a spacecraft to be sent to study Phobos and Deimos, the two moons of Mars, to solve the mystery of how they were formed.   One theory is they were ejected when a large object collided with Mars during the formation of the solar system.  The other is that they were formed independently and captured by Mars’ gravity.  

Speaking later in the day, Cornell space scientist Steve Squyres, the “father” of NASA’s Mars Exploration Rovers Spirit and Opportunity, was very enthusiastic about MMX not only because of the chance to solve the question of the moons’ origin, but also because Phobos probably is “littered” with material from the surface of Mars itself.  When solar system objects collide with Mars, material is ejected into space and Phobos flies through the debris field, with some of the material collecting on its surface.  The material deposited on Phobos would be from places all over the Martian surface rather than just one site.  Getting a sample would be a “science bonanza,” he said.

Squyres chaired the most recent National Academy of Sciences, Engineering and Medicine Decadal Survey for planetary science.  During a panel discussion, he stressed that Decadal Surveys provide advice to U.S. agencies, but they incorporate ideas from the international community, welcoming input through white papers and other mechanisms.   When asked if ISAS uses a process similar to Decadal Surveys to prioritize its science missions, Masaki Fujimoto. Director of Solar System Science at ISAS, said the Japanese space science community is so small that such a process would be overkill.   He said the challenge for ISAS is encouraging scientists to share their ideas, which some are reluctant to do lest another scientist steals it.

NASA Planetary Science Division Director Jim Green discussed the different models that NASA has used over its history for international cooperation on space science missions.  He believes cooperation works best where there is one lead agency and other agencies are junior partners, rather than a 50-50 split.  He noted that cubesats are “the rage” today and could open additional opportunities for cooperation.  Fujimoto agreed and postulated that Japan might deploy a cubesat from a future NASA mission to Jupiter or Saturn.

There was broad agreement on the value of international cooperation and the need to start discussions early.  Lauretta pointed out that one key is the “personal relationships” that scientists in the international community have developed and the importance of getting younger scientists involved. Kuninaka echoed the sentiment, saying “mutual trust” is needed, something “our generation” has, but young people still need to establish for the future.