Japan again cancels launch of the Slim mission to the Moon – 08/27/2023 – Science

For the second time, Jaxa (Japanese Space Agency) canceled the launch of the Slim mission, which could make the country the fifth to land a spacecraft on lunar soil, behind India, which recently celebrated the landing of Chandrayaan-3.

The takeoff was scheduled for Friday night (Brasília time). But, due to bad weather, it ended up being postponed until this Sunday night (27), Monday morning in Japan. The official Jaxa channel even started the transmission, but, moments before the countdown, the cancellation was announced. This time, there is still no prediction of when the next attempt will be.

The Slim mission will fly an X-ray astrophysical satellite aboard a Mitsubishi Heavy Industries H-IIA rocket from the Tanegashima Space Center in Japan.

It will, in fact, be the second chance for the country to carry out a successful landing. The first was conducted by a Japanese company, ispace, with a lander called Hakuto-R. Launched in December last year, the modest vehicle successfully carried out all stages of the flight to the Moon, going there on a low-energy trajectory, which consumed months in space. However, in the last few seconds before consummating the landing, in April of this year, a conflict between the sensors and the on-board computer led to the fuel running out before the probe touched the ground, and it crashed to the ground at high speed. Otherwise, Japan would be the fourth country to land on the moon, not India.

Now, the mission is conducted not by a company, but by the Japanese space agency itself. Slim is an acronym for Smart Lander for Investigating Moon, or Lander Intelligent for Investigating the Moon. The word also plays with the term “slim”, thin in English, since it is a small mission: 590 kg in all, of which two thirds are fuel.

The acronym gives a good clue as to its main purpose: testing automated techniques for performing a high-precision landing on the lunar surface. It is interesting to note that all these landings to date, whether on the Moon, Mars or any other celestial body, have low accuracy. That is, managers can choose the approximate landing region, which has the shape of an ellipse drawn on the ground, but the exact location where the vehicle will land depends on factors beyond their control.

For example, the designated landing area for Apollo 11, the first manned landing in 1969, was an ellipse measuring 20 km by 5 km. Apollo 12 made an impressive display of precision as it was piloted by an astronaut to descend just 163 meters from the unmanned Surveyor 3 probe, launched years earlier by the United States.

Slim intends to improve this number even further, with a much smaller vehicle and without relying on a pilot on board. Its expected precision is one hundred meters, which would make it possible to explore more challenging and scientifically interesting locations, without having to worry so much about nearby geographic features that could endanger the mission. The plan is for it to land inside the Shioli crater, in Mare Nectaris, close to the lunar equator, on the side that always remains facing Earth. This, however, will take time.

Taking a low-energy trajectory (like ispace’s Hakuto-R mission), the probe should only enter lunar orbit three to four months after launch, and then spend between two and four weeks circling the moon before starting. the landing procedure. It will be between the end of this year and the beginning of the next.

Last week, Russia’s first lunar mission in 47 years failed after the spacecraft lost control and collided with the moon. The probe crashed to the surface after a problem occurred during a maneuver before its landing.

Originally planned for October 2021, the release was delayed by nearly two years. The European Space Agency had planned to test its Pilot-D navigation camera by connecting it to the spacecraft, but severed ties with the project after Russia invaded Ukraine in February last year.

If Russia failed, India again created a milestone and became the fourth country to land on the Moon on Wednesday (23), after Russia (then Soviet Union), United States and China – which was the first nation to land on the far side of the satellite in 2019.

Last Thursday (24), the Indian mission began inspecting the surface of the Moon with an exploration robot. Pragyan, “wisdom” in Sanskrit, emerged from the lander hours after India achieved a milestone in its ambitious low-cost space program, sparking huge euphoria across the country. The six-wheeled robot, which runs on solar energy, will travel through the satellite’s little-mapped region. It will also transmit images and scientific data during the two-week mission.