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<\/p>\nThe Chinese space program is preparing to join the Japan Aerospace Exploration Agency (JAXA) and NASA in returning samples from an asteroid to Earth. The Tianwen-2 probe and its Chang Zheng 3B\/E (CZ-3B\/E) rocket launched successfully from Launch Complex 2 (LC-2) at the Xichang Satellite Launch Center in southwest China on Wednesday, May 28, at 17:31 UTC.<\/p>\n<\/p>\n
The CZ-3B\/E Y110 flew on an eastbound path and launched Tianwen-2 on an Earth escape trajectory. Tianwen-2 will orbit asteroid 469219 Kamo\u2019oalewa, also known as 2016 HO3, before flying past Earth en route to Comet 311P\/PANSTARRS. The mission\u2019s launch site, Xichang, in Sichuan province, reached operational status in 1984 and has been used for other Chinese launches beyond Earth, such as the Chang\u2019e 1 lunar orbiter.<\/p>\n
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CZ-3B\/E at the pad. (Credit: CASC)<\/p>\n
The Tianwen-2 mission was 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.<\/p>\n
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.<\/p>\n
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 mission\u2019s science instruments in the spring of 2019 after the Chinese Academy of Space Technology (CAST) conducted a mission design study.<\/p>\n
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Tianwen-2 payload integration with the Chang Zheng 3B\/E. (Credit: China Academy of Sciences)<\/p>\n
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.<\/p>\n
The spacecraft\u2019s 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<\/p>\n
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Tianwen-2 will take one year to reach Kamo\u2019oalewa 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 \u201ctouch-and-go\u201d device similar to ones on NASA\u2019s OSIRIS-REx and JAXA\u2019s Hayabusa2, but is also outfitted with an \u201canchor and attach\u201d method, which has not been used on an asteroid before. For the latter approach, Tianwen-2 features four robotic arms, each with a drill.<\/p>\n
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Illustration of Tianwen-2 approaching the target asteroid 469219 Kamo\u2019oalewa (Credit: CNSA)<\/p>\n
The asteroid Kamo\u2019oalewa, which is a co-orbital near-Earth asteroid, was discovered by the Pan-STARRS telescope at Haleakala Observatory in Hawaii in 2016. Kamo\u2019oalewa got its name in 2019 from the Hawaiian Kumulipo creation chant. In Hawaiian, the name is derived from the words for oscillating space fragment.<\/p>\n
This asteroid is one of several that appear to orbit Earth as it alternately leads and trails Earth in its orbit, but Kamo\u2019oalewa is in fact a \u201cquasi-satellite\u201d influenced by Earth\u2019s gravity but not within its Hill sphere, which is the planet\u2019s gravitational sphere of influence.<\/p>\n
The object\u2019s 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. Kamo\u2019oalewa orbits the Sun every 366 days on average, closely matching Earth\u2019s orbit. It appears to orbit the Earth roughly once every 45 years, but Kamo\u2019oalewa is not a true natural satellite of Earth.<\/p>\n
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Kamo\u2019oalewa (2016 HO3) and its \u201cquasi-satellite\u201d orbit near Earth. (Credit: NASA\/JPL-Caltech)<\/p>\n
The asteroid has been a companion of Earth for over a century and will be 300 million km from Earth by May 2369. Kamo\u2019oalewa may eventually impact an inner solar system body or even be ejected from the Solar System.<\/p>\n
Kamo\u2019oalewa 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.<\/p>\n
Astronomers believe that Kamo\u2019oalewa 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.<\/p>\n
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Lunar Reconnaissance Orbiter mosaic of crater Giordano Bruno on the lunar far side. (Credit: NASA\/GSFC\/Arizona State University)<\/p>\n
These findings, plus the asteroid\u2019s orbit close to Earth, point to a possible lunar origin, perhaps from the crater Giordano Bruno, due to the crater\u2019s 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.<\/p>\n
While Kamo\u2019oalewa 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. Kamo\u2019oalewa, no matter where it formed, is believed to have a silicate composition.<\/p>\n
Tianwen-2 is not the first mission proposed to fly to this asteroid, but it is the first mission that is actually flying to Kamo\u2019oalewa. Graduate research assistants from the University of Colorado in Boulder and S\u00e3o Paulo State University in Brazil proposed a mission to the object in 2017, and NASA proposed Kamo\u2019oalewa as a target for a solar sail mission in 2019.<\/p>\n
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Images of 311P\/PANSTARRS taken by the Hubble Space Telescope. (Credit: NASA\/ESA\/STScI)<\/p>\n
The spacecraft will depart Kamo\u2019oalewa 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 NASA\u2019s Dawn probe being the first to do so between 2011 and 2018.<\/p>\n
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 Earth\u2019s 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.<\/p>\n
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.<\/p>\n
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China\u2019s solar system exploration roadmap for the 2020-2030 timeframe. (Credit: CASC)<\/p>\n
Tianwen 2 is the latest Chinese solar system exploration mission to fly. Tianwen-3 will take advantage of the 26-month Earth-Mars planetary alignment to launch two spacecraft \u2014 a lander\/ascent vehicle and an orbiter\/return vehicle \u2014 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.<\/p>\n
(Lead image: Official photo of the Tianwen-2 launch. Credit: CNSA)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" The Chinese space program is preparing to join the Japan Aerospace Exploration Agency (JAXA) and NASA in returning samples from an asteroid to Earth. The Tianwen-2 probe and its Chang Zheng 3B\/E (CZ-3B\/E) rocket launched successfully from Launch Complex 2 (LC-2) at the Xichang Satellite Launch Center in southwest China on Wednesday, May 28, at […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[4365,7907,3097,8105,7315,1741],"class_list":["post-23808","post","type-post","status-publish","format-standard","hentry","category-news","tag-asteroid","tag-chang-zheng-3b-e","tag-comet","tag-cz-3b","tag-tianwen-2","tag-xichang"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/23808"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=23808"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/23808\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=23808"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=23808"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=23808"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}