Commentary| The Resilience of U.S. Military Space Power
In May 2013, the Pentagon, referring to a Chinese rocket launch, said: “It was a ground-based missile that we believe would be [China’s] first test of an interceptor that would be designed to go after a satellite that’s actually on orbit.” Pentagon spokeswoman Lt. Col. Monica Matoush added: “The launch appeared to be on a ballistic trajectory nearly to geosynchronous Earth orbit.” Earlier, on Jan. 11, 2007, China had successfully launched an anti-satellite missile against one if its own weather satellites in low Earth orbit.
So what do these launches imply? Has China established dominance in space? Does this mean the United States would now be unable to use its satellites in a military engagement with China, say, in the Taiwan Straits?
In the case of intelligence, surveillance and reconnaissance (ISR) satellites that operate predominantly in low Earth orbit, the availability of alternate systems limits the possible gains from anti-satellite attacks.
The U.S. possesses an extensive array of airborne platforms that can duplicate and likely outperform certain battlefield missions conducted by ISR satellites, including the U-2, E-8C Joint Surveillance Target Attack Radar System (JSTARS), RC-135 Rivet Joint, EP-3 (Aries 2), E-3 Sentry and E-2C Hawkeye.
These airborne systems certainly do not make ISR satellites irrelevant. However, U.S. forces would not be completely lost without ISR satellites during a military engagement.
All recent U.S. military operations have extensively employed airborne ISR systems. In the 2003 Operation Iraqi Freedom, for example, coalition Air Forces employed 80 aircraft that flew nearly 1,000 ISR sorties during the initial weeks, collecting 42,000 battlefield images and more than 3,000 hours of full-motion video. They also provided 2,400 hours of signals intelligence coverage and 1,700 hours of moving target indicator data.
An expected retort to this assertion about airborne systems would be: Airborne platforms, unlike satellites, can be easily brought down because they are inside enemy airspace. However, that is not always true. A number of these airborne platforms also have standoff capability.
For example, JSTARS has the capacity to detect, precisely locate and track thousands of fixed and mobile targets on the ground over an area larger than 20,000 square kilometers from a standoff distance in excess of 250 kilometers. The ASARS-2 radar in the U-2 aircraft can take pictures of the battlefield to a range of 162 kilometers. The E-3 AWACS radar is able to survey a volume of airspace covering more than 500,000 square kilometers around it (i.e., 400 kilometers in any direction). The RC-135 Rivet Joint can collect and rapidly analyze signals within a 460-kilometer range. The E-2C Hawkeye is capable of detecting aircraft approaching at a distance greater than 550 kilometers.
All of these platforms should therefore be able to operate outside of China’s inland air defense systems in a hypothetical conflict in the 180-kilometer-long Taiwan Straits. All of these platforms would be used in a conflict there, raising questions about the unique value of attacking U.S. ISR satellites. Why would China choose to focus on attacking these satellites when airborne platforms probably pose a much greater threat and would be easier to attack?
In the case of GPS satellites, the redundancy of the constellation limits what China can achieve. The GPS constellation consists of around 30 satellites in six orbital planes. This orbital arrangement guarantees that the navigation signals of at least four satellites can be received at any time all over the world. To meaningfully impact U.S. performance — for example, to force U.S. ships to operate without access to accurate GPS navigation signals in the Taiwan Straits region — China would have to successfully attack and disable at least six GPS satellites. This is a herculean task. China’s current intercontinental ballistic missiles are not capable of reaching the altitude of GPS satellites. For China to directly reach these altitudes would require the development of more powerful ICBMs or use of its liquid-fuel space launch vehicles. Both are a very costly option.
Even if six GPS satellites were destroyed in an elaborate anti-satellite operation, the degradation in navigation signals would last for a period of only 95 minutes. What would China gain from 95 minutes of GPS degradation? U.S. ships and aircraft have accurate inertial navigation systems that would still permit them to operate in the region. As for the ability to use GPS-guided bombs, the U.S. could shift to laser-guided bombs. In fact, between operations Enduring Freedom and Iraqi Freedom, the Pentagon decreased the use of GPS-guided bombs by about 13 percent and increased the use of laser-guided bombs by about 10 percent.
Finally, in the case of communication satellites, a Chinese anti-satellite operation has its own problem: escalation control. The Naval Telecommunications System that would be supporting the U.S. Navy in a conflict is very elaborate. It comprises tactical communications among afloat units around a battle group, long-haul communications between the shore-based forward Naval Communications Stations and forward-deployed afloat units, and strategic communication connecting those stations with National Command Authority (NCA).
Tactical communication between ship-to-ship, ship-to-air, air-to-ship and air-to-air elements of a forward-deployed battle group needed to coordinate movements are predominantly serviced by high frequency, very high frequency and ultra high frequency radio nets. Close formations (25-30 kilometers) use “line-of-sight” radio. For communication with picket ships and between formed groups — 300-500 kilometers — “extended line-of-sight” radio is used. Long-haul communications are normally conducted in the distances from 750-11,000 kilometers using high frequency and UHF radio links as well as UHF and super high frequency satellite communications. In contrast, the strategic portion of the naval communications is largely dependent on satellite communications. Therefore, the component of the Naval Telecommunications System that China would be able to disrupt with an anti-satellite attack is strategic communications that would connect the NCA with the forward-deployed battle group.
This poses a unique problem. Normally, China should prefer to disable the communication capabilities within the forward-deployed battle group and then negotiate with the U.S. NCA to have it withdrawn or stand down. However, it could only accomplish the opposite. With an anti-satellite attack, China would cut off the forward-deployed battle group from its NCA but not be able to significantly disable the battle group’s ability to execute its naval mission. China could hope that such an attack might force the battle group to stand down. However, it also would have to contend with the possibility that the battle group commander would act more rashly in the absence of direct guidance from the NCA, particularly if combat maneuvers had been initiated. Would China be willing to take such risk? Arguably, the risk might not be worth the potential escalation it might trigger.
The various arguments expounded above paint a nuanced picture of American vulnerabilities in space and the Chinese potential to exploit it. Just because the U.S. armed forces use satellites more than any other military does not make them immediate and obvious targets. Convincing the Chinese of this might be the best way to dissuade their anti-satellite activities.
Jaganath Sankaran is a postdoctoral fellow at the Managing the Atom Project and at the International Security Program at the Belfer Center for Science and International Affairs at Harvard University’s Kennedy School of Government. He was previously a Stanton Nuclear Security Fellow at the RAND Corp. A more detailed version of this op-ed will be published in a forthcoming article in the Strategic Studies Quarterly.