Raumfahrt - JAXA robotic SLIM (Smart Lander for Investigating Moon) Mission -Update3

27.02.2024

Japan Moon lander survives lunar night

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Jaxa produced this render of Slim to show the awkward landing orientation that pointed the solar cells away from the Sun

Japan's Moon lander has survived the harsh lunar night, the sunless and freezing equivalent to two Earth weeks.

"Last night, a command was sent to #SLIM and a response received," national space agency Jaxa said on X.

The craft was put into sleep mode after an awkward landing in January left its solar panels facing the wrong way and unable to generate power.

A change in sunlight direction later allowed it to send pictures back but it shut down again as lunar night fell.

Jaxa said at the time that Slim (Smart Lander for Investigating Moon) was not designed for the harsh lunar nights.

It said it planned to try to operate again from mid-February, when the Sun would shine again on Slim's solar cells. 

"The news that SLIM has rebooted itself after the cold lunar night is significant," said Dr Simeon Barber from the UK's Open University. "Surviving lunar night is one of the key technological challenges to be overcome if we are to establish long-lived robotic or human missions on the Moon."

Dr Barber explained that Slim landed near the Moon's equator, where the lunar surface reaches more than 100C at noon, but then plunges to -130C during the lunar night.

Jaxa said that communication with the lander was terminated after a short time - it was lunar midday, meaning the temperature of the communications equipment was very high.

But it posted the following picture on X, which it said was taken from the lander while it was back in action.

Jaxa said preparations were being made to resume operations when instrument temperatures had cooled sufficiently.

During its previous brief period of re-awakening, Slim was able to study its surroundings in detail and transmit new images to Earth.

Jaxa will be hoping that having survived the lunar night it will be able to continue its work.

Dr Barber said that future landers will need so-called 'active' thermal control - that is the ability to dissipate heat generated on board during the daytime, and then to change into a heat-conserving mode at night to prevent things getting too cold.

"The fact that Slim survived without such a complex design might give us clues as to how electronics really behaves on the Moon," he said. "Plus, we can look forward to more science from Slim!"

The landing in January made Jaxa only the fifth national space agency to achieve a soft touchdown on the Moon - after the US, the former Soviet Union, China and India.

Also in a post on X, Jaxa congratulated the team behind a US spacecraft, the Odysseus Moon lander, for making history on Thursday by becoming the first ever privately built and operated robot to complete a soft lunar touchdown.

Like Slim, it also landed awkwardly. Controllers at the operating company, Intuitive Machines, think their robot tipped on to its side at the moment of touchdown. Odysseus does, however, appear still to be functional and is communicating with Earth.

No pictures from the Odysseus mission at the surface have yet been released.

Quelle: BBC

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Japan’s SLIM moon lander stages unexpected revival after lunar night

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Japan's SLIM moon lander imaged by small rover LEV-2. Credit: JAXA/Takara Tomy/Sony Group Corporation/Doshisha University

HELSINKI — Japan’s space agency made contact with its SLIM moon lander Sunday, despite the spacecraft not being expected to function after lunar night.

Contact with the Smart Lander for Investigating Moon (SLIM) spacecraft was reestablished on Sunday, Feb. 25, the Japan Aerospace Exploration Agency (JAXA) announced via its dedicated SLIM account on X, formerly known as Twitter, early Feb. 26.

The mission team received telemetry from SLIM around 5:00 a.m. Eastern (1000 UTC). The  temperature of the communication equipment was extremely high, according to JAXA, due to the sun being high over the landing area. Communication was terminated after only a short period of time, JAXA stated.

The SLIM team is however now preparing to conduct observations with SLIM’s multiband spectroscopic camera (MBC) later in the lunar day. MBC is designed to ascertain the composition of the lunar surface and could provide insights into the moon’s history. Sunset over Shioli crater, on the rim of which SLIM landed, will occur Feb. 29. 

SLIM was not designed to survive the deep cold of lunar night. Temperatures fall below minus 130 Celsius during the roughly 14-Earth-day lunar nighttime, damaging electronics. Other spacecraft have used radioisotope heater units to provide heating during lunar nights to allow prolonged operations.

The spacecraft—also referred to as “Moon Sniper” for its objective of making a precise landing—made its historic landing Jan. 19. 

That feat saw the country join an exclusive club of the United States, the former Soviet Union, China and India in making successful robotic lunar soft landings. Intuitive Machines has since become the first private entity to land on the moon. The Nova-C lander, named Odysseus, likely tipped over on its side when landing, however. 

SLIM’s operations on the surface have been limited due to the unintended attitude of the spacecraft after landing.

Shinichiro Sakai, SLIM project manager, provided an update to the Space Development and Utilization Subcommittee of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Feb. 26 Japan time.

Sakai reiterated that the landing was hampered by the failure of one of two engines with around 50 meters of descent remaining. This resulted in uncontrolled lateral movement and the lander ending up on its nose, and the main engine pointing upwards.

An image (right) showing a thruster nozzle (circled in red) falling free of the SLIM spacecraft during the final stages of descent onto the moon.
An image (right) showing a thruster nozzle (circled in red) falling free of the SLIM spacecraft during the final stages of descent onto the moon. Credit: JAXA

SLIM was planned to tip onto its side, cushioned by five crushable, 3D-printed aluminum lattice landing legs. Instead, with SLIM’s solar cell facing westwards, away from the sun, the spacecraft was forced to power down just over two hours after landing Jan. 19. Communication with the spacecraft was established on the night of January 28th once sufficient power was obtained from the solar cells.

Sakai said the team is currently conducting a detailed investigation into the cause of the engine malfunction. The team will also consider future countermeasures. SLIM’s precision landing technology could allow greater science returns for future missions, allowing teams to target very specific locations of interest instead of general areas.

SLIM also carried a pair of small, innovative rovers which it successfully deployed onto the moon in the final stages of descent. The 2.1-kilogram Lunar Excursion Vehicle 1 (LEV-1) uses a hopping mechanism, while LEV-2 is a 0.25-kg, baseball-sized, spherical rover. 

LEV-1 transmitted directly to Earth an image of SLIM taken by LEV-2, demonstrating inter-robot radio wave data transmission and revealing the landing state of the main spacecraft. LEV-1 performed seven autonomous hops across 107 minutes, according to Sakai’s presentation.

Quelle: SN

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Update: 28.02.2024

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It's alive! JAXA's SLIM moon lander sends home new photos after surviving frigid lunar night

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