Surprise! SLIM is Awake!!

Nine days after its topsy-turvy landing on the moon, Japan's SLIM probe suddenly woke up and started talking back to Earth yesterday.   

SLIM phoned home on Sunday (Jan. 28) and engineers quickly resumed operations, JAXA officials wrote in a statement on X...

"We immediately started scientific observations with MBC, and have successfully obtained first light," read the JAXA statement, with "first light" referring to the first use of an instrument to take images. MBC, the Multi-Band Camera, is designed to scour the lunar surface for the composition of olivine through analyzing the light signatures, or spectra, of reflected sunlight, according to the Planetary Society. 

Olivine could be a clue to early solar system formation of rocky worlds like our own. The mineral is one of the main parts of the Earth's mantle, and also tends to be concentrated in lunar locations "where the crust is relatively thin," states a 2010 paper in the journal Nature that includes JAXA participation. One of those zones is the moon's south pole, where NASA, Japan and a coalition of other nations under the U.S.-led Artemis Accords plan to send astronauts later in the 2020s.

SLIM's landed in Shioli Crater, a zone filled with old impact rubble within the Mare Nectaris or Sea of Nectar.  The crater is roughly 200 miles south of Mare Tranquillitatis or the Sea of Tranquility - which is where the Apollo 11's first human landing took place in 1969

SLIM sent back photos of its landing zone on Sunday and JAXA is now "sorting out rocks of interest, assigning a nickname to each of them, with intent of communicating their relative sizes smoothly by the names," officials added in an English-language press release.

For reasons known only to the mission planners, they've chosen to name these rocks after dog breeds they estimate as being similar in size to that rock. 

Even better science might be possible soon: "Preparation is underway to promptly conduct 10-band high-resolution spectroscopic observations, once the solar illumination condition improves and SLIM recovers by the power generated by the solar array," the press release added.

JAXA doesn't know how long SLIM will continue to work.  Suddenly waking up must mean that the sun has started to shine on SLIM's solar panels, somehow.  It's not clear to me how much is being illuminated in the pictures of SLIM upside down on the moon, but I wasn't really expecting it to wake up at all.  All we know is that it can't work if the sun can't hit those solar panels.  

How many days until sunset?  Poking around with a NASA interactive photo display of the moon, it looks to me like SLIM can't have more than two more days of sunshine; by January 31 the sun will set.  Recall from earlier stories that SLIM was not designed to survive the two week long, brutally cold, lunar night, much like India's Chandrayaan 3.  They held out hope Chandrayaan would survive the night and start working when the sun rose.  We can hope the same for SLIM.