HELSINKI — China is set to launch its second Tianwen deep space exploration mission late May, targeting both a near Earth asteroid and a main belt comet.
Airspace closure notices indicate a four-hour-long launch window opening at 12:00 p.m. Eastern (1600-2000 UTC) May 28.
Sampling Kamoʻoalewa The roughly 40 to 100-meter-diameter asteroid is considered a quasi-satellite of Earth due to its co-orbital dynamics.
In contrast to the lunar sampling missions, Kamoʻoalewa will have negligible gravity, requiring different approaches for orbiting, approaching and sampling.
The mission was a gateway to Tianwen-3, a pioneering Mars sample return mission set to launch in late 2028.
HELSINKI — To target a main belt comet and a near-Earth asteroid, China will launch its second Tianwen deep space exploration mission in late May.
According to the China Aerospace Science and Technology Corporation (CASC), the Tianwen-2 spacecraft is currently being integrated with a Long March 3B rocket at the Xichang Satellite Launch Center in southwest China. The launch is planned for the end of May, the company announced on May 18.
There is a four-hour launch window that opens at 12:00 p.m., according to airspace closure notices. m. Eastern, May 28 (1600–2000 UTC). Launch windows for the backup are set for May 29 and 30.
Gathering samples from the near-Earth asteroid 469219 Kamoʻoalewa (2016 HO3) and delivering them to Earth by the end of 2027 is the primary objective of Tianwen-2. The main Tianwen-2 spacecraft will swingby using Earth’s gravity to set itself up for a six-year journey to comet 311P/PANSTARRS, while a reentry module containing the samples will be released for atmospheric entry, descent, and landing.
In addition to offering fresh perspectives on small planetary bodies and their evolutions, the mission seeks to enhance China’s planetary exploration capabilities and may have implications for planetary defense and the origins of life.
Kamoʻoalewa is a sample.
Because of its co-orbital dynamics, the asteroid, which has a diameter of about 40 to 100 meters, is regarded as a quasi-satellite of Earth. According to researchers, spectral analyses suggest that Kamoʻoalewa may be a fragment of the moon that was blasted into space after an impact event. The samples will be analyzed in order to determine the asteroid’s composition, nature, and place of origin. Additionally, comparisons with other asteroids will be made.
Up to three sampling techniques will be tried by the spacecraft: touch-and-go (TAG), which uses a rotating brush head; hover sampling, which uses a robotic arm to collect samples while matching the asteroid’s rotation; and anchored sampling, which uses drills at the end of landing legs to press into the asteroid, if the terrain and surface composition permit. Both JAXA’s Hayabusa2 and NASA’s OSIRIS-REx employed the TAG technique.
China has not made public any official, comprehensive plans for the mission, including timetables, sample counts, or a picture of the spacecraft itself. Initially, the spacecraft was supposed to gather 200–1,000 grams of samples for the mission, which was named Zheng He after the Chinese explorer and admiral who was born in the 14th century. According to renderings, the spacecraft will have solar panels that resemble those on NASA’s Lucy spacecraft.
China has successfully returned lunar samples on two occasions, but Tianwen-2 will present additional difficulties due to the reentry module’s higher velocity (12 km/s), which will be the country’s first second-cosmic-velocity atmospheric reentry. In 2023, CASC tested the deployment of high-altitude parachute systems for the mission. Since Kamoʻoalewa will have very little gravity compared to the lunar sampling missions, different strategies will be needed for orbiting, approaching, and sampling.
The Chang’e-2 lunar orbiter made the flyby of 4179 Toutatis in 2012 as part of an extended mission objective, marking China’s first asteroid visit.
follow-up on Comet.
The mission’s comet component will also put the spacecraft’s longevity to the test. Because 311P/PANSTARRS orbits between 1.94 and 2.44 astronomical units from the Sun, it is thought to be a perfect target for research on objects that fall between asteroids and comets.
To learn more about cometary behavior in the main belt, Tianwen-2 will use remote sensing to determine the comet’s orbit, shape, and rotation; analyze its surface composition and volatile elements; and look into dust emissions and activity mechanisms.
It has high-resolution cameras to map geological features and multispectral and infrared spectrometers to study the composition of the surface. A magnetometer will look for lingering magnetic fields, and a radar sounder will probe subsurface structures. Solar wind interactions will be investigated by charged particle detectors, while comet activity will be examined by dust and gas analyzers. It is believed that the Russian Academy of Sciences’ Space Research Institute made contributions to the particle detectors.
Tianwen (which translates to “Heavenly Questions” or “Questions to Heaven”) is the second mission in the Tianwen exploration series. Zhurong was a Mars orbiter and surface rover that was part of the first, Tianwen-1. Tianwen-3, a ground-breaking Mars sample return mission scheduled to launch in late 2028, was made possible by the mission.
Around 2030, Tianwen-4 will launch. It will consist of a smaller, radioisotope-powered spacecraft to flyby Uranus and a solar-powered Jupiter orbiter that will observe the system before entering orbit around the moon Callisto, possibly accompanied by a lander. The missions are also a part of a long-term space science plan and a broader roadmap for planetary exploration that focuses on astrobiology and habitability.
