TOKYO — A high-level Japanese government panel has tentatively recommended proceeding with development of a lower-cost, commercially viable successor to the nation’s workhorse H-2A rocket.

The recommendation to develop the so-called H-3 rocket was handed down May 17 in a draft midterm report by the Space Transportation Systems Subcommittee of Japan’s Cabinet-level Office of National Space Policy (ONSP). The final report is expected in June, and assuming there are no major changes the H-3 program likely will move forward.

“The recommendation is not the final decision on the [replacement for the H-2A] but it is a midterm recommendation for development,” an official with the Japan Aerospace Exploration Agency (JAXA) said May 17. 

The ONSP, which is part of the Cabinet Office of Prime Minister Shinzo Abe, is responsible for Japan’s space policy following several years of reorganization and legal changes. 

The Transportation Systems Subcommittee, set up in March, is responsible within the ONSP for Japan’s launch vehicle development policy based on the ONSP’s second five-year Basic Plan for Space Policy. The Basic Plan, which took effect in March, emphasizes that Japan focus on developing the solid-fuel Epsilon small-satellite launcher together with a “cost effective” successor to the H-2A, according to subcommittee documents.

Epsilon, a three-stage successor to the M-5 small rocket designed to carry small scientific satellites, is slated to debut in August from Japan’s Uchinoura Space Center. 

In a briefing whose title, roughly translated, is “Evaluation of Present Mainstay Rocket Systems and Future Systems Development Methodology,” H-2A prime contractor Mitsubishi Heavy Industries (MHI) of Tokyo proposed a two-stage “New Concept Rocket” with a liquid-fueled core stage and solid-rocket strap-on motors that would be available commercially by 2020 at half the price of an H-2A. The briefing was submitted April 24 to the subcommittee by Yoichi Kujirai, MHI’s executive vice president in charge of space systems.

Japan has long harbored ambitions to commercialize the H-2A, but the vehicle’s price tag, along with availability and logistical issues, have relegated it to the sidelines of the global market. 

MHI had previously proposed a vehicle whose first stage would use an upgraded variant of the H-2A’s LE-7A main engine, dubbed LE-X, and would begin flight testing in 2018, according to JAXA documents. However, the design met with considerable doubts in the ONSP about its cost and commercial viability. 

Hiroshi Yamakawa, chairman of the ONSP’s Space Transportation Systems Subcommittee, declined comment May 17 until the final decision is announced, which he said would be in “about a month.” 

According to its publicly available meeting schedule, the subcommittee is due to make its final decision by the end of June. A development budget, final design parameters and budget will accompany the decision.

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...