On 1 October 2023, SLIM executed its trans-lunar orbit injection burns. The lander entered lunar orbit on 25 December 2023 and landed on 19 January 2024 at 15:20 UTC, making Japan the fifth country to soft-land a spacecraft on the Moon. News reports of technical difficulties made it to Earth, saying that the lander's solar panels were not oriented to the Sun; however, on 29 January, the lander became operational after conditions shifted. It has survived three lunar nights, awakening again in April.[11][12]
SLIM's operation on the Moon was terminated at 22:40 on August 23, 2024 (JST).[4][5]
Background
The main purpose of Japan's first lunar surface mission was to demonstrate precision lunar landing. During its descent, the lander recognized lunar craters by applying technology from facial recognition systems, and determined its current location from observation data collected by the SELENE (Kaguya) lunar orbiter mission. SLIM aimed to perform a soft landing with an accuracy range of 100m (330ft).[9][13][14] In comparison, the accuracy of the 1969 piloted Apollo 11Lunar Module Eagle was an elliptic which was 20km (12mi) long in downrange and 5km (3.1mi) wide in crossrange.[2]
According to Yoshifumi Inatani, deputy director general of the JAXA Institute of Space and Astronautical Science (ISAS), succeeding in this extremely precise landing will lead to enhanced quality of space exploration.[15] The expected cost for developing this project is 18 billion yen, or US$121.5 million.[16]
History
The proposal which later came to be known as SLIM existed in 2005, as the Small Lunar Landing Experiment Satellite (小型月着陸実験衛星).[17] On 27 December 2013, ISAS called for proposals for its next "Competitively-Chosen Medium-Sized Focused Mission", and SLIM was among the seven proposals submitted.[2] In June 2014, SLIM passed the semi-final selection along with the DESTINY+ technology demonstration mission, and in February 2015 SLIM was ultimately selected.[18] From April 2016, SLIM gained project status within JAXA.[19] In May 2016, Mitsubishi Electric (MELCO) was awarded the contract for building the spacecraft.[20]
SLIM was not the first Japanese lunar lander built for operation on the Moon's surface; on 27 May 2016 NASA announced that the OMOTENASHI (Outstanding Moon exploration Technologies demonstrated by Nano Semi-Hard Impactor) CubeSat lander jointly developed by JAXA and the University of Tokyo was to be launched as a secondary payload on Space Launch System (SLS) Artemis 1. OMOTENASHI was meant to deploy a mini lunar lander weighing 1 kg; however, on November 21, 2022, JAXA announced that attempts to communicate with the spacecraft had ceased, because the solar cells failed to generate power when facing away from the Sun.[21] They did not face the Sun again until March 2023.[22]
In 2017, funding difficulties for developing XRISM led to SLIM's launch being switched from its own dedicated Epsilon flight to a rideshare H-IIA flight.[23] The resulting cost savings will be transferred to develop other satellites that are behind schedule due to XRISM.[23]
Lunar Excursion Vehicle 1 (LEV-1) is a lunar rover which moves by hopping. It has its own direct-to-Earth communication equipment, two wide-angle visible light cameras, and electrical components and UHF band antennas courtesy of the MINERVA and OMOTENASHI projects.[24]
Science payloads:
Thermometer
Radiation monitor
Inclinometer
Lunar Excursion Vehicle 2
Lunar Excursion Vehicle 2 (LEV-2) or Sora-Q, is a tiny rover developed by JAXA in joint cooperation with the toy company Tomy, Sony, and Doshisha University.[25] The baseball-sized rover has a mass of 250 g and is equipped with two small cameras. LEV-2 extends its shape to crawl on the lunar surface using two wheels at its sides, a method of locomotion inspired by frogs and sea turtles;[26] it can "run" for approximately two hours.[25] It is the second rover of its kind to attempt operations on the lunar surface; the first was on Hakuto-R Mission 1, which crashed before it could be deployed.[27][28]
Mission
SLIM was successfully launched together with the X-Ray Imaging and Spectroscopy Mission (XRISM) space telescope on 6 September 2023 at 23:42 UTC (7 September 08:42 Japan Standard Time)[3] planning to land near Shioli crater (13.3°S, 25.2°E) via weak stability boundary-like trajectory.[29] SLIM entered lunar orbit 25 December JST.[30]
The lander touched down at the Sea of Nectar (circled).
The lunar lander, nicknamed Moon Sniper for its extremely accurate landing precision within the projected 100 meters (330ft) long landing ellipse, touched down onto the Moon on 19 January 2024 at 15:20 UTC, at the Sea of Nectar (Mare Nectaris), south of the Theophilus crater. Japan thus became the fifth nation to successfully soft land an operational spacecraft on the Moon, after the Soviet Union, United States, China, and India.[31][32]
Although SLIM landed successfully, it landed on its side with the solar panels oriented westwards facing opposite the Sun at the start of the lunar day, thereby failing to generate enough power.[33] The lander was able to operate on internal battery power for a short period of time, but was manually powered down on 19 January 2024 at 17:57 UTC (20 January 02:57 Japan Standard Time) to prevent over-discharge of the battery.[21]
The two lunar rovers, deployed while the lander was hovering just before it touched down, worked as planned, with LEV-1 communicating independently to ground stations.[34] LEV-1 conducted seven hops over 107 minutes on the lunar surface. Images autonomously taken by Sora-Q (a capability it shares with its sister rover)[35] showed the SLIM had landed at a 90-degree angle, effectively on its nose, and there had been the loss of an engine nozzle during descent and even possible damage to its Earth-oriented antenna.[36] Irrespective of wrong attitude and loss of communication with the lander, the mission is already successful given confirmation of its primary goal: landing within 100m (330ft) of its landing spot.[37][38][36] JAXA gave itself 60 out of 100 for the landing.[26]
After the shutdown on 19 January 2024, the mission's operators still hoped that the lander would wake up in a few days when the Sun would be correctly oriented so sunlight would hit the now askew solar panels.[34] The two rovers, LEV-1 and Sora-Q, continued to operate autonomously as planned.[35] On 25 January JAXA informed the LEV-1 rover has completed its planned operational period on the lunar surface, depleted its designated power, and in a standby state on the lunar surface. While the capability to resume activity exists contingent on solar power generation from changes in the direction of the Sun, efforts will be maintained to continue receiving signals from LEV-1.[39]
On 28 January, the lander resumed operations after being shut for a week. JAXA said it re-established contact with the lander and its solar cells were working again after a shift in lighting conditions allowed it to catch sunlight.[40] After that, SLIM was put in sleep mode for the impending harsh lunar night. SLIM was expected to operate only for one lunar daylight period, or 14 Earth days, and the on-board electronics were not designed to withstand the −120°C (−184°F) nighttime temperatures on the Moon.
Second lunar day
On 25 February 2024, JAXA sent wake-up calls and found SLIM had successfully survived the night on the lunar surface while maintaining communication capabilities.
Since it was midday of the lunar day on 25 February 2024, the temperature of the communications payload was extremely high, so communication was terminated after only a short period of time. JAXA was preparing for resumed operations, once the temperature has fallen sufficiently. This feat of surviving the lunar night without a radioisotope heater unit had previously been achieved only by some landers in the Surveyor Program.[41][42]
Third lunar day
On 27 March 2024, SLIM survived its second lunar night and woke up, sending more images back to Earth, showing "perseverance."[43] JAXA said "According to the acquired data, some temperature sensors and unused battery cells are starting to malfunction, but the majority of functions that survived the first lunar night was maintained even after the second lunar night."[44]
SLIM completed its second overnight operation in the early hours of March 30th, and went dormant again.[45]
Fourth lunar day
On 23 April 2024, it survived its third lunar night and woke up sending more images back to Earth.[46] JAXA said on the social media platform X that SLIM’s key functions were still working despite repeated harsh cycles of temperature changes.[47]
The Agency stated that they "plan to attempt to resume operation again in mid to late May, when SLIM’s solar cells start generating electricity."[48]
Fifth lunar day
JAXA sent commands for recovery on 24 and 25 May, when it was assumed that power had been restored, but the radio waves from SLIM could not be confirmed.[49] JAXA conducted the operation again on the night of the 27th, but there was no response from SLIM. As the sun has set around SLIM and power generation is no longer possible, this lunar day's operation has unsuccessfully ended.[50]
JAXA plans to try operating SLIM again next month when it is expected to have sufficient solar power. The power was turned off overnight, so JAXA hopes that the entire system will be reset and restarted.[51]
↑ Days from the New Moon. '15' means the Full Moon.
Related Research Articles
The Japan Aerospace Exploration Agency (JAXA) is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orbit, and is involved in many more advanced missions such as asteroid exploration and possible human exploration of the Moon. Its motto is One JAXA and its corporate slogan is Explore to Realize.
A Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon, including both crewed and robotic missions. The first human-made object to touch the Moon was Luna 2 in 1959.
A lunar lander or Moon lander is a spacecraft designed to land on the surface of the Moon. As of 2024, the Apollo Lunar Module is the only lunar lander to have ever been used in human spaceflight, completing six lunar landings from 1969 to 1972 during the United States' Apollo Program. Several robotic landers have reached the surface, and some have returned samples to Earth.
A rover is a planetary surface exploration device designed to move over the rough surface of a planet or other planetary mass celestial bodies. Some rovers have been designed as land vehicles to transport members of a human spaceflight crew; others have been partially or fully autonomous robots. Rovers are typically created to land on another planet via a lander-style spacecraft, tasked to collect information about the terrain, and to take crust samples such as dust, soil, rocks, and even liquids. They are essential tools in space exploration.
IKAROS is a Japan Aerospace Exploration Agency (JAXA) experimental spacecraft. The spacecraft was launched on 20 May 2010, aboard an H-IIA rocket, together with the Akatsuki probe and four other small spacecraft. IKAROS is the first spacecraft to successfully demonstrate solar sail technology in interplanetary space. The craft's name is an allusion to the legendary Icarus, who flew close to the Sun on wings made of bird-feathers and wax.
A lunar rover or Moon rover is a space exploration vehicle designed to move across the surface of the Moon. The Apollo program's Lunar Roving Vehicle was driven on the Moon by members of three American crews, Apollo 15, 16, and 17. Other rovers have been partially or fully autonomous robots, such as the Soviet Union's Lunokhods, Chinese Yutus, Indian Pragyan, and Japan's LEVs. Five countries have had operating rovers on the Moon: the Soviet Union, the United States, China, India, and Japan.
The (Japanese) Lunar Exploration Program is a program of robotic and human missions to the Moon undertaken by the Japanese Aerospace Exploration Agency (JAXA) and its division, the Institute of Space and Astronautical Science (ISAS). It is also one of the three major enterprises of the JAXA Space Exploration Center (JSPEC). The main goal of the program is "to elucidate the origin and evolution of the Moon and utilize the Moon in the future".
MINERVA are a series of rovers developed by the Japanese space agency JAXA for the purpose of exploring asteroid surfaces. The first MINERVA was part of the Hayabusa mission, and MINERVA-II are a series of three rovers for Hayabusa2. On 12 November 2005, MINERVA rover was deployed from Hayabusa orbiter with aim to land on asteroid 25143 Itokawa. However, the landing failed as MINERVA missed the asteroid and ended up on heliocentric orbit. On 21 September 2018, first two MINERVA-II rovers successfully landed on asteroid 162173 Ryugu. The third MINERVA-II rover malfunctioned before deployment from the Hayabusa2 orbiter, but it was released anyway on 2 October 2019 to perform gravitational measurements before impacting the asteroid a few days later.
OMOTENASHI was a small spacecraft and semi-hard lander of the 6U CubeSat format intended to demonstrate low-cost technology to land and explore the lunar surface. The CubeSat was to take measurements of the radiation environment near the Moon as well as on the lunar surface. Omotenashi is a Japanese word for "welcome" or "Hospitality".
The year 2024 is expected to exceed 2023's 223 orbital launches. So far, the year saw the successful first launch of Vulcan Centaur, Gravity-1, Ariane 6, and notably more developmental launches of SpaceX's Starship – with IFT-5, and IFT-6 planned for this year. Additionally, the final launch of a Delta family rocket occurred in April with a Delta IV Heavy. In May, China launched the Chang'e 6, the first sample return from the far side of the Moon. The Polaris Dawn mission conducted the first ever commercial spacewalk in September.
The Innovative Satellite Technology Demonstration Program is a series of spacecraft missions for testing technology and ideas put forward by universities and private companies. The program demonstrates various experimental devices and technology in space by providing flight opportunities. It is managed by the JAXA Research and Development Directorate. According to JAXA, the goal of this program is to test high risk, innovative technology that will lead to the space industry gaining competitiveness in the international field.
RAPIS-1 is a satellite launched on 18 January 2019 which for over a year was used to test seven technology demonstration projects. RAPIS-1 was developed and operated by Axelspace Corporation, under the coordination of the Japanese space agency JAXA.
The Lunar Polar Exploration Mission (LUPEX), also known as Chandrayaan-5 in India, is a planned joint lunar mission by the Indian Space Research Organisation (ISRO) and Japan Aerospace Exploration Agency (JAXA). The mission would send an uncrewed lunar lander and rover to explore the south pole region of the Moon no earlier than 2026. It is envisaged to explore the permanently shadowed regions on the Moon. JAXA is likely to provide the H3 launch vehicle and the rover, while ISRO would be providing the lander.
DRUMS is an experimental spacecraft that will test proximity operation near space debris. The microsatellite carries two 'mock space debris' which once deployed will be used as a target for demonstrating approach and contact.
KOSEN-1 is a technology demonstration satellite that will test the deployment of an antenna for observing radio waves emitted from the planet Jupiter. It is a 2U CubeSat, and carries a 7 m (23 ft) antenna. The CubeSat was jointly developed by the National Institute of Technologies in Japan. National Institute of Technologies is known as 'kosen' in Japanese. KOSEN-1 was launched on 9 November 2021 by an Epsilon launch vehicle, as part of the Innovative Satellite Technology Demonstration-2 mission.
RAISE-2 was a smallsat for technology demonstration, part of the Japanese space agency JAXA's Innovative Satellite Technology Demonstration Program. RAISE-2 was launched on 9 November 2021 as the main satellite of Innovative Satellite Technology Demonstration-2. RAISE-2 was developed by Mitsubishi Electric.
Hakuto-R Mission 1 was a failed private Japanese uncrewed lunar landing mission built and operated by ispace, which was launched in December 2022 for an attempted lunar landing in April 2023.
Sora-Q is a miniature Lunar rover designed and made by Japanese space agency JAXA, toy manufacturer Tomy, Sony, and Doshisha University.
References
1 2 "小型月着陸実証機(SLIM)プロジェクト移行審査の結果について"[Regarding the results of the Smart Lander for Investigating Moon (SLIM) Project Transition Review](PDF) (in Japanese). JAXA. 14 July 2016. Archived from the original(PDF) on 15 July 2016. Retrieved 2 September 2016.
1 2 "小型月着陸実証機（SLIM）の月面活動の終了"[End of lunar surface activities for the Smart Lander for Investigating Moon (SLIM)]. JAXA. 26 August 2024. Retrieved 27 August 2024.
↑ Tatsuaki Hashimoto (30 November 2005). "小型月着陸実験衛星"(PDF) (in Japanese). Archived from the original(PDF) on 5 March 2016. Retrieved 22 June 2016.
↑ "深宇宙探査技術実証機 DESTINY+"(PDF) (in Japanese). 7 January 2016. Archived(PDF) from the original on 28 January 2022. Retrieved 23 June 2016.
↑ "ISASニュース 2016.5 No.422"(PDF) (in Japanese). Institute of Space and Astronautical Science. 27 May 2016. Archived(PDF) from the original on 11 April 2023. Retrieved 23 June 2016.
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
