Last month, a private satellite tracking company spotted a Chinese
spacecraft apparently grabbing and throwing a dead satellite away into a
"graveyard" orbit.
Something out of a Star Wars movie occurred in Earth's orbit last
month.
A Chinese satellite was spotted in late January grabbing another long-dead
satellite and days later throwing it into a "graveyard" orbit 300 km away,
where objects are less likely to hit spacecraft.
These rare events were presented by Dr. Brien Flewelling in a webinar hosted
by the Center of Strategic and International Studies and Secure World
Foundation last month. Flewelling is the chief space situational awareness
architect of ExoAnalytic Solutions, a private U.S. company that tracks the
position of satellites using a large global network of optic
telescopes.
The Chinese SJ-21 satellite was seen on January 22 changing its usual place
in the sky to approach decommissioned satellite Compass-G2. A few days
later, SJ-21 attached to G2, altering its orbit.
Chinese officials haven't yet confirmed that the apparent space tug
occurred.
Over the course of the next few days, the spacecraft couple started dancing
westward, ExoAnalytic's video footage showed. By January 26, the two
satellites separated, and G2 was kicked into oblivion.
The Compass-G2, or BeiDou-2 G2, is a spacecraft from China's BeiDou-2
Navigation Satellite System that failed shortly after launching in 2009. For
more than 10 years, the metal carcass has been wandering around Earth
alongside millions of other pieces of space trash.
SJ-21, which launched in October 2021, has now returned to a geostationary
orbit (GEO) just above the Congo Basin. GEO happens when a satellite orbits
Earth over the equator at the same speed the planet rotates.
From the Earth's point of view, satellites in GEO seem to be standing still,
barring a wobble or two. This type of orbit is sometimes called a Clarke
orbit, named after British sci-fi writer Arthur C. Clarke. He popularized
the idea of GEO in a 1945 paper promising to revolutionize
telecommunications.
Less than two decades later, the first geostationary satellite was launched.
China's space tug: A service or a threat?
There's nothing wrong with throwing out the trash — many other countries
have launched or are currently developing technologies to clear space
junk.
Japan launched its ELSA-d mission in March 2021, designed to test space
debris capturing and removal technologies. The European Space Agency plans
to launch its own trash removal mission in 2025.
However, despite the seeming ubiquity of efforts to develop and implement
space junk disposal technology, some U.S. officials have expressed worry
over Chinese trash disposal satellites like the SJ-21.
James Dickinson, commander of the US Space Command said in April 2021 that
technology like China's SJ-21 "could be used in a future system for
grappling other satellites."
But is there a real threat?
In its 2021 counterspace report , the Secure World Foundation said
that there is strong evidence that both China and Russia are working to
develop technology with "counterspace capabilities" — the ability to
destruct space systems.
However, the report said, Chinese official statements have remained
"consistently aligned to the peaceful purposes of outer space" and there is
no proof that they have facilitated any destructive or counterspace
operations.
A 2021 report by the Chinese Aerospace Studies Institute (CASI), a
United States Air Force think tank maintained that SJ-21's use will likely
be restricted to testing methods of space garbage disposal.
Space maintenance
The CASI report concluded that SJ-21 is most likely one of China's On-Orbit
Servicing, Assembly, and Manufacturing (OSAM) satellites.
Many space agencies have been developing OSAM missions for decades. These
could be, for example, spacecraft designed for refueling or repairing
existing satellites — or disposing of space waste.
Since the beginning of space activities in the '60s, more than 6,000
launches have delivered over 50,000 objects in orbit, according to the US
Space Surveillance Network. More than 30,000 artificial objects are orbiting
our planet, of which only about 5,000 are functioning, according to the
ESA's Space Debris Office .
And that's just counting the objects large enough to be tracked. The US,
Russia, China and India have all blown satellites in space generating huge
amounts of new smaller debris.
ESA numbers show that more than 300 million smaller objects are flying
through space at incredible speeds of up to 30,000 km/h, almost 5 times the
speed of the fastest bullet.
The ESA started testing OSAM projects in 1990 with the GSV (the
Geostationary Servicing Vehicle) program, which was intended to grab and
repair broken satellites in GEO.
The famous and successful optics repair of the Hubble Space Telescope in
December 1993 is another example of an OSAM mission at work.
NASA has plans for several more OSAM missions, including OSAM-1 and OSAM-2.
The latter is designed to 3D print components in space, with the hope of one
day being able to build, directly in space, parts too big to fit inside any
rocket.