Brian G. Chow and Henry Sokolski
July 10, 2020
The Defense Intelligence Agency warned in January 2019 that China likely will field in 2020 a ground-based laser weapon that can counter low-orbit space-based sensors. By the mid-to-late 2020s it may field higher power systems that could damage the structures of non-optical satellites.
How real is the threat? Analysts have already identified five Chinese laser bases. One in Xinjiang has four main buildings. One of these buildings is thought to be for tracking satellites, while equipment in the other three could be used to dazzle or disable satellite sensors. If the Xinjiang facility is representative of the other four, all five bases can be located and are vulnerable to aerial attacks.
In addition to these bases, China operates several satellite laser ranging stations. These have been used to determine the orbits of satellites and space debris but could be used to damage U.S. and allied satellite sensors.
Of the world’s 50 satellite laser ranging stations, five fixed stations are in Shanghai, Changchun, Beijing, Wuhan and Kuming. Two Chinese satellite laser ranging stations are mobile.
The ranging system at the Shanghai station uses a laser with a relatively low average power of 2.8 watts. The wattage at other stations are most likely the same or lower. Another laser of 60 watts at the Shanghai station has been used routinely to measure space debris. Calculations show that a 1-watt laser has 1 in 1,000 chance to cause permanent damage to a sensor, while a 40-watt laser would double the chance. These odds are low but likely to increase.
In the near term China’s top priority is to deny America and its allies imagery with high resolution of 10 centimeters or better. Fortunately, to damage a satellite’s optical elements such as pixels and filters, an offensive anti-satellite laser would have to be located within roughly 10 kilometers of what one wants to take a picture of.
What should Washington do to counter sensor-damaging lasers? First, it should determine how many of the Chinese targets it wants to take pictures of that have a laser base or fixed satellite laser ranging station within roughly 10 kilometers. There are probably only a few such laser-protected targets.
Second, our military and intelligence analysts need to estimate the risks and costs of snapping pictures from space of these laser-protected targets (i.e., the chance of our satellites’ sensors being damaged and what their repair or replacement costs might be) and the benefits of getting such imagery. Such an analysis would likely recommend that the United States and its allies:
- Take pictures whenever possible during peacetime, as the chance of damage is far higher during crisis.
- Update imagery less frequently, because fewer trips mean less chance of being hit.
- Use as low a resolution for imagery as much as possible, as low-resolution sensors and their satellites are cheap and numerous compared to dedicated military imagery satellites
Third, the United States should secure imagery of all needed resolutions, including 10 centimeters or better, any way it can using commercial and dedicated military systems during peacetime, crisis and wartime. Once it has a diversified group of imagery providers, laser damage to a few of our sensors would become far less valuable to our adversaries, leading them not to initiate such attacks in the first place.
Finally, the United States should extend the 2010 New Strategic Arms Reduction Treaty, which expires in February 2021, to keep its formal prohibitions on interference with national technical means of verification (including sensor-carrying satellites) in force. To the extent that Washington can bring China into arms negotiations with the Russians, it should focus on getting Beijing formally to agree to this prohibition.
The U.S. government will need to do more in the years ahead. Today, Chinese lasers must be located within roughly 10 kilometers of whatever Washington wants to snap pictures of to have any hope of beaming into American satellites’ telescope openings and damaging their sensors inside. Mid-decade, though, when Beijing acquires higher powered lasers, at least one of China’s lasers will be in range to damage several of our low earth orbiting satellites every day. As a result, Washington will not only have to make our satellite constellations resilient and harden some satellites’ exteriors and sensors, it must be prepared to disable China’s laser systems if they attack our satellites.
During this same period, the United States will also have to pay attention to Chinese satellite laser ranging stations and high power lasers that will have gone mobile. Because these mobile systems are likely to be dual-use, they cannot be banned. Instead, the United States and its allies should disadvantage any hostile use with diplomatic measures that would afford warning of such.
This could best be achieved by pushing for an international agreement to register all mobile dual-use lasers (including their locations), require their operators to announce their planned movement a month in advance, and demand their movements be broadcast in real time.