China’s Tiangong-2 laboratory reenters atmosphere. (July 19, 2019)

After nearly three years in orbit, China’s second prototype space station module, Tiangong-2, reentered the Earth’s atmosphere earlier this morning, July 19. Officials from the Chinese Manned Space Engineering Office announced on July 13 that the module would be deorbited on the 19th. The office stated in November 2018 that Tiangong-2 would reenter sometime in 2019. Tiangong-2 used its onboard engines late in the evening of July 18 to lower its orbit, preparing for an early-morning reentry today. Cameras on board the laboratory captured rare footage of the vehicle as it began plummeting through the Earth’s upper atmosphere. The video cuts out shortly after the glowing reaches its highest intensity.

Officials stated that the laboratory reentered the atmosphere at 9:06am EDT in an area of the South Pacific Ocean known as the spacecraft graveyard.

This region of the Pacific is often used for spacecraft and satellites to reenter as it provides a safe, unpopulated area for any surviving fragments to fall in.

Tiangong-2′s final orbit, visualized by Harvard’s Jonathan McDowell. The yellow slanted line represents the portion of the station’s orbit where it broke apart in the atmosphere. P/c: Jonathan McDowell The 8.6 ton, 34-foot module was launched on a Long March 2F rocket from the Jiuquan Satellite Launch Center September 15, 2016. One month later, the two man Shenzhou-11 crew docked to the station for a 30-day mission, China’s longest crewed flight to date.  One of the experiments launched during the crew’s operations was the Banxing-2 microsatellite, which photographed the joint complex in orbit for the first time.  China perfected the technologies necessary for orbital operations with the uncrewed Tianzhou-1 mission, an automatic cargo freighter. Launching in April, 2017 on a 60-day mission, Tianzhou-1 developed the procedures necessary for automatic docking and propellant transfer. Both Tiangong modules and the Tianzhou-1 mission were technological pathfinders for the procedures China will use on their larger, modular space station, known as Tianhe. China’s first space station prototype, Tiangong-1, famously made an uncontrolled reentry in April, 2018, following more than six years on orbit. Officials intended for that module to be controlled during its descent but ground controllers lost communications with the craft in March, 2016.

Tiangong-2 spent a total of 1,036 days, 22 hours, 54 minutes and 56 seconds in orbit. For our coverage of Tiangong-2′s mission, click here. Click here for our coverage of Shenzhou-11, and click here for our coverage of the Tianzhou-1 flight.

P/c: Weibo/Andrew Jones

China’s iSpace performs first ever Chinese private sector launch.

China’s rapidly expanding aerospace industry achieved a significant milestone Thursday, July 25, with the first ever successful launch of a commercially-developed rocket.

Beijing Interstellar Glory Space Technology Ltd, known as iSpace, launched their Hyperbola-1 rocket at 1pm Chinese Standard Time, or 1am EDT, from the Jiuquan Satellite Launch Center in the Gobi desert. The rocket carried four payloads; three of them were attached to the rocket’s upper stage while the fourth, the CAS-7B radio satellite, was launched for Chinese Central Television. Hyperbola-1 stands more than 20.8 meters tall (65.2 feet) with a diameter of 1.5 meters (4.6 feet). Two of the rocket’s three stages are fueled by solid propellant while the vehicle’s third stage consists of liquid propellant.

This marked the first time a launch vehicle developed by a private company, rather than the state-run China Aerospace Science and Technology Corporation orbited a satellite. Two other Chese NewSpace firms, LandSpace Technology Corporation and OneSpace Technology Co, attempted orbital launches in late 2018 and early 2019 but were unsuccessful. 

iSpace plans on using Hyperbola-1 as a testbed for technology needed for Hyperbola-2, a 98-foot, two stage, reusable liquid fueled rocket powered by an in-house developed JD-1 methalox engine. The company hopes this could launch two tons to low Earth orbit by 2021.

Burning liquid Methane and Oxygen, methalox engines are becoming popular in the commercial space industry as the most efficient means of reusable rocket engine technology. SpaceX is developing their methalox Raptor engine for the Starship and Super Heavy launch vehicles.

Tiangong-1 plunges back to Earth over Pacific Ocean. In the middle of its projected four-hour reentry window, China’s Tiangong-1 space station module fell to Earth Sunday evening, April 1. The U.S. Strategic Command’s Joint Force Space Component Command (JFSCC) confirmed the laboratory’s fiery demise at 8:16pm EDT, or 0016 Coordinated Universal Time over the South Pacific ocean. Using a global system of sensors and optical devices as well as orbital missile-detection satellites, JFSCC confirmed the station’s harmless reentry over the ocean just a few hundred kilometers from the ‘spacecraft graveyard.’’ Defunct satellites and space stations are usually directed to deorbit over a vast area of the South Pacific so that any remaining components can fall harmlessly into the sea. With Tiangong-1 no longer controllable, its precise impact point was impossible to predict.

Tiangong-1 impacted the south Pacific Ocean at 8:16pm EDT (0016 UTC) 780 kilometers east of American Samoa. P/c: Spaceflight101. Imagery of the reentry has not yet surfaced, however, astronomer Justin Cowart may have found the smoke trail created by the station’s fragments in satellite images. 

Chinese Space Station Tiangong-1 prepares to for uncontrolled deorbit. (Saturday, March 31, 11am EDT.) In the weeks leading up to the Skylab space station’s uncontrolled deorbit in 1979, billions of people across the Earth wondered where the remains of NASA’s first space station might land. Almost four decades later, that same question of uncertainty plagues another space station in its final days - China’s Tiangong-1. Launched in September 2011 as the country’s first prototype space station, Tiangong-1 hosted two Shenzhou crews totaling six people during its 1,630-day - 4.5 year - operational lifespan. The station continued to send telemetry and data on Earth-sensing equipment and robotic experiments to ground controllers for an additional two and a half years following June 2013′s Shenzhou 10 mission, going silent in early 2016.

Earth based observers noted the station slowly spinning in mid-2016, raising the possibility that China had lost any ability to communicate and subsequently control the laboratory. China reluctantly admitted in early 2016 that the station experienced a power failure in March which lead to the loss of ‘data services.’ 

Initial estimates of its reentry were projected for late 2017 and were further refined towards a late-Feburary to early April 2018 timeframe. 

As the weeks to reentry have become days, the reentry timeframe for Tiangong-1 has now been projected for the afternoon of Sunday, April 1st, with an 11-hour margin of error. The specific time and location of reentry is determined by multiple factors, including solar activity and the spacecraft’s shape. 

Since the station is in an orbit inclined 43 degrees to the equator, only locations on the Earth’s surface between 43 degrees north and south longitude are potential landing sites. While three-fourths of the Earth’s surface is covered by water, the 42.8 degree orbit of Tiangong actually raises the probability of fragments impacting land to around 38%.

European Space Agency graphic showing the potential reentry area of Tiangong-1 and the Earth’s population density in that area.

Only a small portion of the station is expected to survive reentry, with the friction of the atmosphere vaporizing most components. Around 20-30% of the station could survive, which for Tiangong could be anywhere from 1.5 to 3 tons. Thicker pieces such as thruster components, docking mechanisms, pressurization tanks and solar array joints may survive to reach the Earth’s surface. While this may sound shocking, the mathematical chances of Tiangong-1 injuring a human being are remarkably low - just one in 5,000. By comparison, when NASA’s Skylab reentered over Australia, the chances of it striking a human were 1 in 500. Being struck by lighting is a 1 in 3,000 chance during the entire average lifespan of a human.

Although the precise time and location of Tiangong-1′s demise is not yet known, it is certain that the laboratory will cease to exist by the middle of this week. Tiangong’s legacy continues on through its upgraded sister craft, Tiangong-2, which launched on its own groundbreaking mission in 2016. Both ‘Heavenly Palaces’ - as their English translations mean - have helped China develop the spacecraft, technology, and methods necessary to begin the construction of a large modular space laboratory smaller than the current International Space Station. The Chinese Space Station, also known as Tianhe, is slated to launch its first module in 2020.