China to launch the Tianwen-2 asteroid sample return mission

Date:
Wed, 28 May 2025 14:52:14 +0000

Description:
The Chinese space program is preparing to join the Japan Aerospace
Exploration Agency (JAXA) and The post China to launch the Tianwen-2 asteroid sample return mission appeared first on NASASpaceFlight.com .

FULL STORY ======================================================================

The Chinese space program is preparing to join the Japan Aerospace
Exploration Agency (JAXA) and NASA in launching a mission to return samples from an asteroid to Earth. The Tianwen-2 probe and its Chang Zheng 3B/E (CZ-3B/E) rocket are scheduled to launch from Launch Complex 2 (LC-2) at the Xichang Satellite Launch Center in southwest China on Wednesday, May 28, at 17:30 UTC.



The CZ-3B/E Y110 will fly on an eastbound path to launch Tianwen-2 on an
Earth escape trajectory. Tianwen-2 will orbit asteroid 469219 Kamooalewa,
also known as 2016 HO3, before flying past Earth en route to Comet 311P/PANSTARRS. The missions launch site, Xichang, in Sichuan province, reached operational status in 1984 and has been used for other Chinese launches beyond Earth, such as the Change 1 lunar orbiter. CZ-3B/E at the
pad. (Credit: CASC)

The Tianwen-2 mission will be the 97th flight of the CZ-3B/E variant since
its introduction in 2007 and the 168th overall mission of the Chang Zheng 3 series. The CZ-3B/E, over 56m tall and three meters wide, is an enhanced version of the original CZ-3B. It features a larger first stage and liquid boosters and a payload capacity of 3,300 kg to a heliocentric orbit, like the one Tianwen-2 will use. See Also Tianwen-2 launch Thread Tianwen-2 science Thread Space Science coverage NSF Store Click here to Join L2

The CZ-3B/E, like other CZ-3 variants, uses toxic hypergolic propellants for its first and second stages and four liquid rocket boosters. Its third stage uses liquid hydrogen and liquid oxygen as propellants, like other upper
stages such as the Centaur used by many US launch vehicles. The CZ-3B/E is a workhorse of the Chinese space program, especially for geostationary
launches, and is comparable to the retired Atlas V 411 variant in
performance.

Tianwen-2 was first outlined in 2018 by the Chinese Academy of Sciences in a deep space exploration roadmap for the 2020-2030 decade. The China National Space Administration (CNSA) solicited international proposals for the
missions science instruments in the spring of 2019 after the Chinese Academy of Space Technology (CAST) conducted a mission design study. Tianwen-2
payload integration with the Chang Zheng 3B/E. (Credit: China Academy of Sciences)

The spacecraft, built by CAST, incorporates eight science instruments as well as a return capsule to bring over 100 g of asteroid samples back to Earth. Tianwen-2, formerly known as ZhengHe after the Chinese Ming Dynasty explorer, masses around 2,000 kg and is designed for a 10-year mission duration. The mission will be run by CNSA from its facilities and will make use of Chinese deep space network facilities.

The spacecrafts eight science instruments include a visible infrared imaging spectrometer, a thermal radiation spectrometer, a multispectral camera, a medium field color camera, a detection radar, a magnetometer, charged and neutral particle analyzers, and an ejecta analyzer. A pair of navigational instruments is also on board Tianwen-2: a narrow field of view navigation sensor as well as a laser integrated navigation sensor

Tianwen-2 will take one year to reach Kamooalewa after its launch, reaching the object in 2026, and will orbit the asteroid before attempting to retrieve a sample. The spacecraft is equipped with a touch-and-go device similar to ones on NASAs OSIRIS-REx and JAXAs Hayabusa2, but is also outfitted with an anchor and attach method, which has not been used on an asteroid before. For the latter approach, Tianwen-2 features four robotic arms, each with a drill. Illustration of Tianwen-2 approaching the target asteroid 469219 Kamooalewa (Credit: CNSA)

The asteroid Kamooalewa, which is a co-orbital near-Earth asteroid, was discovered by the Pan-STARRS telescope at Haleakala Observatory in Hawaii in 2016. Kamooalewa got its name in 2019 from the Hawaiian Kumulipo creation chant. In Hawaiian, the name is derived from the words for oscillating space fragment.

This asteroid is one of several that appear to orbit Earth as it alternately leads and trails Earth in its orbit, but Kamooalewa is in fact a quasi-satellite influenced by Earths gravity but not within its Hill sphere, which is the planets gravitational sphere of influence.

The objects minimum approach distance to Earth is just over four and a half million kilometers, outside of the Earth Hill sphere within one and a half million kilometers of the planet. Kamooalewa orbits the Sun every 366 days on average, closely matching Earths orbit. It appears to orbit the Earth roughly once every 45 years, but Kamooalewa is not a true natural satellite of Earth. Kamooalewa (2016 HO3) and its quasi-satellite orbit near Earth. (Credit: NASA/JPL-Caltech)

The asteroid has been a companion of Earth for over a century and will be 300 million km from Earth by May 2369. Kamooalewa may eventually impact an inner solar system body or even be ejected from the Solar System.

Kamooalewa is a fast rotator, with a rotational period of roughtly 28
minutes. The asteroid is currently thought to have a size of approximately
100 x 81 x 46 m, with a 72 m diameter according to a 3D model from light
curve data.

Astronomers believe that Kamooalewa may be a remnant of the lunar surface
that was blasted away from the Moon by an asteroid impact earlier in its history. Scientists used two Arizona-based observatories, the Large Binocular Telescope and the Lowell Discovery Telescope, to measure the spectrum of
light from the object. The asteroid has a more reddish spectrum than others, and appears similar to space-weathered lunar minerals. Lunar Reconnaissance Orbiter mosaic of crater Giordano Bruno on the lunar far side. (Credit: NASA/GSFC/Arizona State University)

These findings, plus the asteroids orbit close to Earth, point to a possible lunar origin, perhaps from the crater Giordano Bruno, due to the craters size and age. Giordano Bruno, on the far side highlands, is a Copernican age crater, meaning it dates from just over one billion years old to the present.

While Kamooalewa is believed to be a fragment of the Moon, it could also be
an S-type or L-type asteroid that formed elsewhere. S-type asteroids, also known as stony asteroids, have a silica composition. L-type asteroids are
also thought to be stony, but with a strongly reddish spectrum. Kamooalewa,
no matter where it formed, is believed to have a silicate composition.

Tianwen-2 is not the first mission proposed to fly to this asteroid, but it
is the first mission that will actually fly to Kamooalewa. Graduate research assistants from the University of Colorado in Boulder and So Paulo State University in Brazil proposed a mission to the object in 2017, and NASA proposed Kamooalewa as a target for a solar sail mission in 2019. Images of 311P/PANSTARRS taken by the Hubble Space Telescope. (Credit: NASA/ESA/STScI)

The spacecraft will depart Kamooalewa in 2027 and eject its sample return capsule when it flies by Earth before its planned exploration of comet 311P/PANSTARRS. Tianwen 2 is scheduled to reach the comet in 2034 and will go into orbit around the object. Assuming all goes well, the spacecraft will become one of the few to orbit two distinctly different objects in the solar system other than the Earth and the Moon, with NASAs Dawn probe being the first to do so between 2011 and 2018.

Object 311P/PANSTARRS, an active asteroid with an asteroid-like orbit but comet-like characteristics, was discovered with the Pan-STARRS telescope in 2013. 311P/PANSTARRS, also known as P/2013 P5, orbits at approximately twice the Earths distance from the Sun and rotates around the Sun in just over
three Earth years. It is believed to be around 480 m in diameter.

The Hubble Space Telescope discovered six comet-like tails emanating from 311P/PANSTARRS in 2013, while pre-discovery images of the object from 2005 show negligible cometary activity. These tails are thought to be debris being ejected from a fast-spinning rubble pile asteroid. The object, categorized as an active asteroid, was also categorized as a main-belt comet after this discovery. Chinas solar system exploration roadmap for the 2020-2030 timeframe. (Credit: CASC)

Tianwen 2 is not the only Chinese solar system exploration mission in work. Tianwen-3 will take advantage of the 26-month Earth-Mars planetary alignment to launch two spacecraft a lander/ascent vehicle and an orbiter/return vehicle in 2028 as a Martian sample-return mission. China also plans additional robotic and later crewed missions to the Moon as well as the Tianwen-4 probe to Jupiter, marking its first exploration of the outer solar system.

(Lead image: The Tianwen-2 mission being prepared for launch at the Xichang Satellite Launch Center. Credit: CNSA)

The post China to launch the Tianwen-2 asteroid sample return mission
appeared first on NASASpaceFlight.com .



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