How Did Japan’s SLIM Moon Lander Survive the Frigid Lunar Night When Chandrayaan-3’s Vikram Couldn’t

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How Did Japan’s SLIM Moon Lander Survive the Frigid Lunar Night When Chandrayaan-3’s Vikram Couldn’t?
By Ashmita Gupta16 hours agoTWC India
Japan's upside-down SLIM moon lander wakes up on lunar surface (JAXA)
Japan's upside-down SLIM moon lander wakes up on lunar surface
(JAXA)
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Weeks before the US-built spacecraft Odysseus took a tumble on the lunar surface, Japan’s much-awaited Moon Sniper mission had also landed on its nose �" at this point, upcoming lunar missions should probably keep an eye out for any banana peels strewn about the Moon. JAXA took it in stride and was busy celebrating SLIM’s (for Smart Lander for Investigating Moon) precise landing when the lander got back up, dusted itself and began beaming back pictures as if nothing happened.

After this miraculous comeback, the lander went into a peaceful slumber, as it wasn’t designed to withstand the unforgiving cold of the lunar night. But then (drumroll), SLIM woke up again, defying all odds! Despite landing at a tilted angle that left its solar panels facing the wrong direction, the lander managed to briefly awaken after napping for nearly a month.

"Last night, a command was sent to #SLIM and a response received, confirming that the spacecraft has made it through the lunar night and maintained communication capabilities," JAXA officials tweeted. The electronics were operational despite surface temperatures being at 100°C, the team wrote in another post, space.com reported.


The lander also managed to conduct a bit of science with its high-resolution camera when the Sun's angle shifted. SLIM transmitted new photographs to Earth over the weekend, showing a new zone of the Moon “which was not visible last time”. These achievements are nothing short of impressive, considering the Japanese lander was not even designed to withstand the harsh lunar temperatures.

Well, SLIM has since taken a break again after communicating for a while. And while we’re extremely happy for JAXA, we can’t help but feel just the teensiest bit salty, considering our nation’s Vikram lander had failed to awaken after a lunar night, even after having relatively higher odds of doing so.

How Did SLIM Succeed Where Vikram Failed?
While being put to sleep early in September 2023, Pragyan rover’s battery was fully charged, its receiver was kept on and its solar panels were oriented in a way that they would receive sunlight at lunar sunrise. Similarly, Vikram's payloads were also kept on. Despite all this, Vikram and Pragyan did not come back to life. Conversely, SLIM managed to catch some sunlight and awaken in spite of its orientation not being the most ideal.

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Further, just like Vikram, SLIM had not been equipped with any heating units to keep its payloads warm, reducing its likelihood of waking up after enduring the cold. So what gave it an edge over ISRO’s mission?

For one, the JAXA mission landed in the mid-latitudes on the near side of the Moon, within a 100-metre target area near the Shioli crater. Chandrayaan-3, on the other hand, landed close to the Moon's south pole. While both of these regions can present challenging conditions, the lunar poles are way colder due to extended periods of darkness.

In the poles’ permanently shadowed areas, temperatures can plummet to around -233°C or even lower, and never receive direct sunlight. This meant that Vikram and Pragyan’s batteries would’ve had to overcome more extreme temperatures than SLIM.

It remains unclear whether there were any other factors that worked in favour of JAXA but couldn’t for ISRO. But to its credit, the Japanese lander has met its main objectives of making a precision landing, sending two rovers onto the surface for their operations, and picking up scientific data in the surrounding area. Its story serves as a testament to the perseverance and innovation of the Japanese space program.

While the challenges remain, the lander’s successful revival offers a glimmer of hope for future lunar exploration and sheds light on the complexities of navigating the harsh lunar environment. The coming months will be crucial in determining the ultimate fate of SLIM and its ability to continue its scientific mission on the Moon.

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Author's Note

Kindly review