NASA's NEOWISE Satellite Mission Concludes: Over a Decade of Asteroid Discovery and Sky Mapping

This week, NASA sent the final command to the NEOWISE satellite, which maps the sky in the mid-wave infrared range.

On August 8, administrators at the Jet Propulsion Laboratory (JPL) in California shut down NEOWISE (Wide-Earth Near-Infrared Probe) its radio transmitter, so the spacecraft, still in orbit around Earth, is now permanently inactive. About the NEOWISE mission at the beginning of January this year, when the program was about to end, we wrote in more detail (at the end of our article at the time, we also gave a generous selection of our previously related news). Initially sensitive to four infrared wavelengths (3.4, 4.6, 12 and 22 μm), the space telescope known as WISE was launched in 2009, and its task was to map the sky (many times). The mission was originally planned for less than a year, until the detectors’ coolant, which is sensitive in the two longer wavelength bands, runs out. The successful sky survey was then continued in the 3.4 and 4.6 μm bands, which do not require cooling, under the name NEOWISE, but only until February 2011, when NASA decided to cancel it for economic reasons – more precisely, to the spacecraft to sleep during the winter. . Then, in December 2013, NASA decided to revive and reconnect, mainly to discover small celestial bodies (asteroids) and comets in the solar system that could be a threat to Earth. This revived mission has now come to an end after more than ten years. If we count from the original launch date, WISE/NEOWISE operated for almost 15 years – of course, the winter period must be subtracted from its actual operating time.

NEOWISE’s fate was sealed by running out of an onboard conveyor. Therefore, he could no longer make the necessary movements to maintain his path. Without an orbit update, with the help of the current strong solar activity, it will sink relatively quickly, with the expectation that by the end of 2024, it will enter the dense atmosphere and to destroy Amy Mainzer (University of California, Los Angeles), principal investigator of NEOWISE who joined the research team back in 2003, said that the end of the satellite was not really a difficult time. After all, it worked much longer than originally planned, so it is considered a great success. In addition, the collected data will certainly be used by astronomers for many decades to come, who, of course, will use them to study not only small celestial bodies in the solar system, but also on stars, star clusters, gas and dust clouds, and even distant galaxies and active galactic nuclei.

Over the past ten years, NEOWISE has detected more than 3,000 near-Earth objects, 215 of which were detected by this instrument.

The NEOWISE image taken on 1 August 2024 shows details of the southern sky, including the constellation Kemence (Fornax). This was the 26,886,704th and last picture taken by the satellite. (Picture: NASA / JPL-Caltech / IPAC / UCLA)

With the completion of the NEOWISE mission, NASA’s planetary protection program does not stop, it even enters a new phase. Its successor, the NEO Surveyor, is already in the works (Near Earth Object Monitor) called a new spacecraft, which is an outer part of the Sun-Earth system (L₁) will go to its Lagrange space and carry a telescope with a mirror diameter of 50 cm. (The telescope on board NEOWISE had a diameter of 40 cm.) The goal is to fulfill the Congressional mandate, that is, to find at least 90% of the near-Earth asteroids larger than 140 m and determine their orbits. According to Mainzer, all this takes time, because these celestial bodies are very small and faint. According to estimates, after the first 5 years, the targets will be approx. two thirds of them are found, and it takes 10 years to pass the 90% level. NEO Surveyor is expected to launch in September 2027 at the earliest, with a planned operational life of 12 years. During the transition period until then, it will rely on data from NASA’s ground-sky monitoring programs. In fact, they will continue to work with the data from the NEOWISE mission that just ended. Thanks to the new procedures, there will certainly be several small celestial bodies that will be discovered later.

NASA’s NEOWISE Satellite Mission Concludes: Over a Decade of Asteroid Discovery and Sky Mapping

The next generation infrared sky mapping satellite, NEO Surveyor. Weight approx. It will weigh 1.3 tons and its detectors will be sensitive in the 4-5.2 and 6-10 μm bands. (A fantasy picture: NASA)