WASHINGTON — Japanese company ispace has updated the design of its commercial lunar lander while delaying its first flight by a year.
The company unveiled the revised design of its Hakuto-R lander July 30 as it completed the critical design review of the spacecraft. The lander is scheduled to make its first mission in 2022, launching on a SpaceX Falcon 9.
Since a preliminary design review in 2018, ispace has reduced the size of Hakuto-R. Previously 3.5 meters high and 4.4 meters wide with its landing legs deployed, the lander is now 2.3 meters high and 2.6 meters wide. The spacecraft’s mass has decreased from 1,400 to 1,050 kilograms, primarily by reducing the amount of propellant on board.
A smaller lander is less expensive to develop, said Ryo Ujiie, manager of the lander system engineering group at ispace, during a call with reporters July 30. It also reduces the size and complexity of the landing legs.
The spacecraft will use a different trajectory to go to the moon, employing a low-energy transfer orbit that requires less propellant but takes roughly twice as long as previously planned. “We had to pick a more propellant-efficient orbit” given the reduction in propellant, said Chit Hong Yam, manager of the mission design and operations group. “We’re confident that, with enough checking, we should be able to execute this orbit.”
While the overall lander is smaller, it still maintains a payload capacity of 30 kilograms. Once on the surface, likely at one of several mid-latitude sites on the moon under consideration by ispace, it will operate for 12 days.
The company also announced that it selected ArianeGroup to provide the propulsion for the lander. That includes one main thruster and six smaller “assist” thrusters, as well as eight small thrusters for its reaction control system.
Carlos Rabsiun, manager of the quality control and assembly, integration and testing group, said ispace chose ArianeGroup because the performance of its thrusters best met its lander design, as well as a favorable cost and schedule. “We compared them to various international proposals, and it was the best one.”
The company raised a $95 million Series A round in late 2017, and previously planned to launch its first lander mission in 2021, a schedule the company confirmed last fall. In its announcement of the revised lander design, though, the company said that the mission was now scheduled for 2022 “in response to technical issues which arose in recent months.”
In the call with reporters, ispace declined to go into details about those technical problems, other than to say it provided them with additional time to reassure customers and other stakeholders about the lander’s development. “To increase our mission success probability,” said Ujiie, “we decided to spend more time to solve that issue.”
Under this revised schedule, assembly of the lander will start in Japan next year, with final assembly, integration and testing work at an ArianeGroup facility in Germany. It will then be shipped to the United States for its Falcon 9 launch in 2022. A second lander mission remains scheduled for 2023.