Fireball over California thought to have been caused by part of Chinese spacecraft re-entering atmosphere.

Witnesses across California between San Diego and Sacramento, as well as the Las Vegas in Nevada, have reported observing a bright fireball meteor at about 1.40 am local time (8.40 am GMT) on Tuesday 2 April 2024. The fireball is described as having moved from southwest to northeast, over the central part of the state. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry, as is believed to have been the case on this occasion.

The 2 April 2024 Fireball seen from Ontario, California. American Meteor Society.

The fireball is thought to have been caused by a part of a Chinese spacecraft which launched on 29 November 2022 re-entering the atmosphere. The Shenzhou 15 spacecraft caried three taikonauts (the Chinese equivalent of astronauts) to the Tiangong Space Station. The taikonauts returned to Earth on 3 June 2023 aboard the Shenzhou 15 re-entry module, the only portion of the craft designed to re-enter the atmosphere safely. The remaining portion of the spacecraft has been on a decaying orbit since this time, finally re-entering the atmosphere this week.

The portions of a Shenzhou spacecraft. Ilya Kharlamov/Wikimedia Commons.

See also... 

Chinese rocket crashes into the Atlantic Ocean off the coast of Mauritania.

A 30 m long, 17-8 tonne Chinese rocket-stage fell into the Atlantic Ocean off the coast of Mauritania, slightly after 3.30 pm GMT on Monday 11 May 2020, from the Wenchang launch centre on Hainan Island in southern China. The piece of space junk was the main rocket stage of a Long March 5B heavy launcher which took off on Tuesday 5 May. The rocket was initially lifted from the ground by three smaller kerosene fuelled rocket boosters, then powered the main lift of the spacecraft by using a cryogenic hydrogen system. The rocket delivered a prototype manned crew capsule (without any crew) into orbit, and was expected to burn up high in the atmosphere as it fell back. However, the much of the body appears to have survived, and was tracked by the US Air Force, passing over New York about 15 minutes before eventually vanishing off the coast of Mauritania.

The trajectory of the Long March 5 rocket-booster (orange line), and it's last known location. Jonathan McDowell/Twitter.

Pieces of space junk re-entering the atmosphere, and even reaching the ground (or sea) are not that unusual, but objects of this size are somewhat rare, with the last object of this size having been the 39 tonne Soviet Salyut 7 Space Station in February 1991, which crashed into the Pacific Ocean southern Pacific Ocean. The Colombia Space Shuttle, which was disintegrated during re-entry in February 2003 is not usually counted as 'space junk' as it was manned, but weighed 2000 tonnes, so this could be considered the largest such object.The Russian Fobos-Grunt Probe, which fell into the Pacific Ocean in January 2012, after an unsuccessful launch in November 2011, weighed about 13 tonnes.

The re-entry orf the Long March stage was planned, but it's survival into the lower atmosphere was unexpected, as it was essentially a hollow tube. It is possible that only the rocket engines survived re-entry, reducing the size of the object at impact. In either event, a returning rocket launcher presents a far lower risk to anyone on the ground than an asteroid of similar mass, as its velocity is much lower, with asteroids travelling far faster due to their orbital velocity, as their trajectory seldom matches that of the Earth.

The launch of the Long March 5B heavy launcher from Hainan Island on 5 May 2020. CNN.

See also...

Follow Sciency Thoughts on Facebook.

Myanmar jade mine struck by possible space debris.

Residents of Lone Khin near Hpakant in Kachin State, Myanmar, were alarmed by a mysterious object which fell from the sky on Thursday 10 November 2016. The object is described as being a metal cylinder 3.7 m in length and 1.2 m in diameter, with protruding wires and Chinese writing on the outside. After striking the ground a first time the object bounced about 50 m before coming to rest in an open area at a jade mine (Myanmar is the world's largest producer of jade). A second smaller piece of debris is reported to have damaged a nearby house, though nobody was injured by either event.

The object which fell from the sky onto a Myanmar jade mine on 10 November 2016. Yanniang Pyi Sone Aung.

The object was initially thought to be a piece of an aircraft engine, but has now been linked to the launch of an experimental X-ray pulsar navigation spacecraft, the Maichong Xing Shiyan Weixing (which is intended to test the theory that radio emissions from pulsars could be used to navigate spacecraft) on a Long March Rocket 11from the Jiuquan Satellite Launch Center in Inner Mongolia, China, earlier that day. These rockets comprise a series of booster stages that are jettisoned as the craft rises through the atmosphere. As with similar rockets launched by other nations, these jettisoned stages are intended to fall back to Earth over open water or sparsely populated regions (the Jiuquan Satellite Launch Center is in the Gobi Desert), though the possibility of one being blown to a different area by high winds does exist.

See also...

Follow Sciency Thoughts on Facebook.

China's Chang'e-3 Probe touches down on the Moon.

On 1 December 2013 the China National Space Administration launched a Long March-3B Rocket from its Xichang Satellite Launch Centre in Sichuan Province, carrying its Chang'e-3 Lunar Probe on the first leg of its mission to the Moon. The probe entered the orbit of the Moon on 6 December, and touched down in Sinus Iridum on 14 December.

The launch of the Chang'e-3 Lunar Probe. Xinhua.

The probe made a soft landing on the surface of the Moon, using chemical rockets to slow its descent before landing on four shock absorber equipped legs, the first probe to land on the Moon in this way since the Soviet and US missions of the Cold War period, which ended in the 1970s, though the more sophisticated computer equipment available today meant the probe was able to analyze its landing site better than the Cold War probes, and if needs be adjust its landing trajectory more rapidly. The successful landing makes China the third country to achieve a soft landing on the Moon (an Indian probe made a hard landing -  i.e. crashed directly into - on the Moon in 2008).

Having landed on the Moon the Chang'e-3 Probe deployed a rover vehicle, the Yutu (Jade Rabbit), intended to explore the geology of a 3 km³ area around the landing site. As well as a set of cameras and mass spectrometers (used to determine rock chemistry) Yutu is equipped with a ground penetrating radar, which should enable it to determine the structure of the lunar surface to a depth of 30 m, the first time that an attempt to examine the lunar subsurface has been made.

The Yutu Rover on the surface of the Moon, as seen by a camera on the Chang'e 3 Probe. CCTV.

In addition to the instruments on the rover, the Chang'e 3 Probe itself has its own soil probe, as well as cameras with which to survey its instruments. In addition it has a pair of ultraviolet telescopes, one of which is designed to study the Earth's plasmasphere (inner magnetosphere), and the other to study more distant astronomical objects, such as galaxies, variable stars and quasars, making Chang'e the first lunar astronomical observatory, something scientists from several nations have long hoped to achieve (the Moon has almost no atmosphere, making its skies as clear as those achieved from space, but is a solid surface, preventing the need for a telescope to constantly adjust its position to remain pointing in the same direction).

While the probe has landed successfully on the Moon and begun returning information, its lauch as not entirely without mishap; several pieces of debris fell from spent rocket stages onto a village in Suining County in neighbouring Hunan Province, damaging a number of homes, but not causing any injuries.

See also NASA releases digitally remastered view of Copernicus Crater, How the Moon got its strange magnetic field, Recent tectonic activity on the moon? Could we mine the moon for titanium? and Is the Moon younger than we think?

Follow Sciency Thoughts on Facebook.