Debris from one Russian antisatellite missile demonstration in November is producing surges of close encounters, in some occasions tens of thousands per week, with live satellites in LEO (low Earth orbit).
Such incidents, named “conjunction squalls” by SSA (space situational awareness) business COMSPOC, were first spotted in January and resulted from the peculiar conditions of the November 15 Russian ASAT test which damaged Cosmos 1408 spacecraft and generated thousands of pieces of debris.
The squalls can lead to thousands of close encounters, or conjunctions, during only a few days. “During the beginning week of April, in that week only, there will be 40,000 conjunctions that we forecast just from that one occasion,” stated Travis Langster, who works as the general manager and vice president of COMSPOC, during a discussion on the 24th yearly FAA Commercial Space Transportation Conference February 17.
Those surges occur from the engagement of Cosmos 1408 debris with clusters of remote sensing spacecrafts. Cosmos 1408 was in the orbit at an angle of 82.3 degrees, whereas many remote sensing spacecraft are in the sun-synchronous orbits with slopes of roughly 97 degrees. As the orbits undergo precession, the debris intersects the orbits of remote sensing spacecraft — but traveling in the opposite direction.
“When they sync up, you have the ideal storm: they’re in the very same orbit plane yet counter-rotating, crossing one another twice an orbit, again and again,” said Dan Oltrogge, integrated operations and research’s head at COMSPOC, in a question and answer session. Those squalls linger for numerous days until the orbits undergoes precession out of sync.
COMSPOC initially noted an increase of conjunctions at the start of the year, tied to a group or “Flock” of Dove imaging cubesats run by Planet. That first wave peaked at roughly 4,000 daily conjunctions, characterized as approaches within ten kilometers, on January 2. A 2nd conjunction squall, peaked at roughly 2,000 conjunctions a day January 25, linked to another pair of Planet satellites.
COMSPOC is anticipating an even larger conjunction squall in the beginning of April as the debris contacts multiple Flocks of Planet cubesats, reaching a high of over 14,000 conjunctions on a day, April 5. Another storm is forecast with those identical cubesats approximately 6 months later, although with a peak just about 50% as intense when debris spreads out and also reenters.
Because of the scale of its constellation, Planet is subjected to some of the most severe effects of Russian ASAT debris, although it is not alone. “This is true for any Earth-observing system at this height that uses sun-synchronous orbits,” Oltrogge added. “We anticipate a significant impact.”
According to COMSPOC, conjunctions encompassing all active spacecraft in low Earth orbit would peak at around 50,000 per day during the conjunction storm in early April. This includes a baseline level of approximately 15,000 per day that is unrelated to the ASAT test, as well as tests involving Planet’s satellites and other companies and organizations including Satellogic, Spire, and Swarm.