A Chinese weather satellite may have been destroyed or damaged last March.
The cause? A collision with space junk, the remnants of a Russian Zenit-2 rocket launched in 1996, according to U.S. Space Force, whose 18th Space Control Squadron – which tracks orbital traffic – detected the incident.
“Several days prior to March 18, 2021, the 18 SPCS recognized an increasing probability that a piece of space debris, likely about the size of a computer keyboard, would collide with an active Chinese satellite, the Yunhai 1-02,” a Space Force spokesman told me in an email. “The probability of collision was 0.2 percent at the highest, but in an effort to provide timely and actionable information, the 18 SPCS issued multiple notifications about the potential conjunction to the Chinese government, with the first message being sent on March 15. On March 18, the 18 SPCS posted a standard notification on www.space-track.org confirming there was a debris-causing event in the vicinity of Yunhai 1-02.”
“After extensive analysis of the event and associated data, 18 SPCS concluded the debris-causing event was very likely due to a collision between Yunhai 1-02 and a piece of SL-16 debris (1996-051Q/rocket body launched by Russia in 1996), which was updated in the space catalog on August 14. The 18th SPCS is currently tracking approximately 35 pieces of debris associated with the Yunhai 1-02 and is sharing the data through www.space-track.org.”
The space junk that causes the collision apparently came from a Russian Zenit-2 rocket that launched the Tselina-2 spy satellite in September 1996. China’s Yunhai 1-02 was launched in September 2019 to study the Earth’s oceans and atmosphere. But on March 18, the Chinese satellite suffered a breakup that left numerous pieces of debris in its wake, the 18th SPCS tweeted on March 22. That tweet was spotted by Harvard astrophysicist Jonathan McDowell, who determined that a piece of debris from the Russian rocket was the culprit.
“Orbital data for the debris object and for Yunhai show that they passed within 1 kilometer [0.6 miles] of each other at the time of the breakup, per my calculation using Space Force orbital data,” McDowell told me.
However, China tried to blame the Yunhai mishap on the United States, whose decommissioned NOAA-17 weather satellite broke up on March 10. “Chinese media seized on speculation online that its fate was related to US weather satellite NOAA-17, which had broken apart 10 days before and created debris,” noted the South China Morning Post. “The China National Space Administration did not release a statement on the incident at the time.”
Whether Yunhai 1-02 has been totaled – or is still functioning minus a few chunks gouged out by the collision — is unclear. “If you have questions on the status of the Yunhai 1-02, please contact the Chinese government,” U.S. Space Force told me.
The incident raises an interesting question: can China sue Russia for damaging its spacecraft? This could be the first time such a claim has been pursued.
“An international treaty, the Convention on International Liability for Damage Caused by Space Objects, applies when the ‘space object’ of one country causes harm to the ‘space object’ of another country,” says Mark Sundahl, director of the Global Space Law Center at Cleveland State University. “However, in order to find liability under the convention, there must be a determination of ‘fault’ on behalf of the offending country. The convention provides for the creation of a claims tribunal if a claim is brought. A formal claim has never been brought under the treaty, although the USSR agreed to compensate Canada for damage caused by the Kosmos 954 accident [a Russian satellite that scattered radioactive debris over northern Canada] without a formal claim being brought.”
“What exactly would constitute ‘fault’ has not been settled under international law,” Sundahl added. “China would have to prove negligence or similar bad behavior.”
Space debris – bits and pieces of spent rocket boosters, or old and forgotten satellites still in orbit – has become a menace to manned and unmanned spaceflight. At orbital speeds of 18,000 miles per hour, even a marble-sized piece of debris can do serious damage to spacecraft.
“The 18th Space Control Squadron is responsible for tracking more than 32,000 man-made objects in space and their reentry to Earth on a daily basis,” Space Force points out.
But on the positive side, outer space is a big place. “Collisions between space debris and active satellites happen very infrequently,” says Space Force. Unfortunately for Yunhai 1-02, its luck ran out.