A Japanese spacecraft just took an enormous step toward pulling off the nation’s first-ever moon landing.
Japan’s robotic SLIM moon lander arrived in lunar orbit on Christmas Day (Dec. 25) as planned, the Japan Aerospace Exploration Agency announced. The spacecraft entered lunar orbit at 2:51 a.m. EDT (4:51 p.m. Japan Standard Time, 0751 GMT).
“The Japan Aerospace Exploration Agency (JAXA) is pleased to announce that the Smart Lander for Investigating Moon (SLIM) was successfully inserted into lunar orbit at 16:51 (Japan Standard Time, JST) on December 25, 2023,” JAXA officials wrote in an update. The spacecraft is in an elliptical orbit that takes 6.4 hours to circle the moon, coming inside 373 miles (600 kilometers) of the lunar surface at its closest point and reaching out to 2,485 miles (4,000 km) at its farthest.
The milestone keeps SLIM (“Smart Lander for Investigating Moon”) on track to aim a lunar touchdown on Jan. 19. Success in that endeavor could be historic; up to now, only 4 nations — the Soviet Union, the U.S., China and India — have soft-landed a craft on the moon.
Related: Missions to the moon: Past, present and future
The 8.8-foot-long (2.7 meters) SLIM launched on Sept. 6 together with XRISM, a robust X-ray space telescope.
Each Japanese spacecraft deployed into Earth orbit, and XRISM stays there today. But SLIM left our planet’s gravity well on Sept. 30, starting an extended, circuitous and energy-efficient path to the moon.
That trek got here to an end today, when SLIM inserted itself itself into lunar orbit. The probe will now start gearing up for its touchdown attempt, during which it’ll attempt to live as much as its “Moon Sniper” nickname: SLIM goals to hit its landing-zone goal with an accuracy of 330 feet (100 m) or less, paving the best way for much more ambitious exploration efforts down the road.
SLIM “is a mission for researching the pinpoint landing technology essential for future lunar probes and verifying this on the surface of the moon with a small-scale probe,” JAXA officials wrote in a mission description.
“By creating the SLIM lander, humans will make a qualitative shift towards having the ability to land where we wish and not only where it is straightforward to land, as had been the case before,” they added. “By achieving this, it’ll turn out to be possible to land on planets much more resource-scarce than the moon.”
If all goes in line with plan, SLIM may even deploy two miniprobes onto the lunar surface after touching down. These daughter craft will snap photos, help mission team members monitor SLIM’s status and supply an “independent communication system for direct communication with Earth,” JAXA officials wrote within the SLIM mission’s press kit.
SLIM is not the primary Japanese spacecraft to achieve lunar orbit; the Hiten probe did so in 1990, followed by SELENE (“Selenological and Engineering Explorer”), also often called Kaguya, in 2007.
And Hakuto-R, a lander built by Tokyo-based company ispace, arrived in lunar orbit this past March. Hakuto-R tried to the touch down on the moon a month later but crashed after its sensors got confused by the rim of a lunar crater.