An optical communications device Sony helped develop was installed on Kibo, the Japanese experimental module on the International Space Station, in 2020. Credit: NASA

TOKYO — Japan is pressing forward with ambitious plans to enhance its role on the international space station (ISS), announcing its intentions to better utilize the Kibo laboratory and build a variant of the H-2 Transfer Vehicle (HTV) that would be capable of bringing cargo back to Earth.

In an Aug. 11 briefing to Japan’s Space Activities Commission, Japan Aerospace Exploration Agency (JAXA) officials outlined two enhancement options that would enable the HTV to return cargo from the space station before 2020 and put the automated cargo supply ship on the path to eventually carrying humans, said Seiichi Ueno, director of JAXA’s Human Space Systems Directorate’s program management and integration department.

One option for the so-called HTV with Return Vehicle (HTV-R) entails equipping the 4.4-meter diameter HTV with a 2.6-meter diameter pressurized capsule that would detach itself from the belly of the expendable HTV and deorbit payloads of up to 300 kilograms. The more ambitious option JAXA is considering  involves creating a 4-meter diameter pressurized capsule capable of returning 1.6 tons. Both designs would be considered stepping stones to adding human capability to the HTV-R sometime after 2020, Ueno said in an Aug. 13 interview.

Ueno said evolving the HTV to support cargo-return missions has been part of Japan’s plans since development of the space tug began in the 1990s. The pursuit of an HTV-R took on greater urgency in May when the Japanese government recommended that Japan develop basic technologies for independent human space capabilities.

The present-generation HTV, which launched for the first time in September 2009 atop Japan’s new heavy-lift H-2B rocket, is set to play a major role in keeping the ISS in service, ferrying roughly 6 tons of cargo on each of the six space station resupply missions planned between next January and 2015.

In preparation for the HTV-R’s development phase, JAXA will conduct a so-called mission definition review for the new vehicle by the end of this year, Ueno said.

“JAXA will determine which option to take as the best path … for future human transportation, considering the cost-benefit trade-off and the available and affordable funding level. The demerit for Option 2 would be mainly the cost and the deployment schedule. Option 1 will leave more work for us to get to human transportation capability,” he said.

Ueno declined to say what either HTV-R option would likely cost. He said whichever way Japan goes, a first flight between 2016 and 2018 is “likely” but ultimately depends on technical challenges and budget.

JAXA’s plans for HTV-R are an important part of Japan’s desire to make the most of the Kibo lab beyond 2015, according to Shigekazu Matsuura, director of the Office of Space Utilization Promotion at the Ministry of the Education, Culture, Sports, Science and Technology.

After the United States announced in February its intention to help keep the space station in service through 2020, NASA and the other space agencies involved in the multinational undertaking in March pledged to reach consensus on how best to extend the operational life of the orbital outpost. Japan, for its part, conducted a major review of the future of the ISS and Japan’s role. In a report published in June, Japan’s Space Activities Commission, which has oversight of JAXA, strongly endorsed making the most of the station, praising the ISS program for its major role in supporting technology development, particularly in developing Japan’s human spaceflight capability and in maintaining the nation’s space industrial base.

“About 650 Japanese companies are involved in the space station in one way or another, and saying you are involved has tremendous international prestige,” Matsuura said in an Aug. 10 interview.

Atsushi Sunami, director of the Science and Technology Policy Program at Japan’s National Graduate Institute for Policy Studies and a key author of the Space Activities Commission report, said that participation in the ISS is important for Japan’s soft diplomacy and power projection.

“Japan is the only Asian nation to participate in the ISS at this moment,” Sunami said. “Given the rise of China and followed by India … policymakers understand the importance of Japan’s continuous presence in the ISS perhaps more easily.”

Japan spends about 40 billion yen ($467.5 million) annually on space station utilization. Matsuura said the Ministry of the Education, Culture, Sports, Science and Technology hopes to maintain Japan’s space station spending as near as possible to that level through 2015 and beyond.


A graduate of the Columbia Graduate School of Journalism, where he won the Horgan Prize for Excellence in Science Writing, Paul Kallender-Umezu is co-author of “In Defense of Japan: From the Market to the Military in Space Policy” (Stanford University...