Eyes in the sky: The increasing importance of very low Earth orbit (VLEO) for national security

The war in Ukraine spotlighted the power of satellite imagery in new ways, and has already changed the way the military uses orbital reconnaissance tactically and to shift public perception. As an example, when Russia was initially staging to invade Ukraine, the United States government purchased more commercial satellite imagery to provide a flow of information to the public and Ukraine at unprecedented levels, leaving no room for question of Russia’s intent. In the evolving landscape of satellite imagery for aerospace and defense, the strategic significance of very low Earth orbit (VLEO) is becoming increasingly apparent. Specifically, satellites flying at half the altitude of legacy low Earth orbit (LEO) satellites — commonly 250 to 350 km — are twice as close to the action on the ground, and therefore better able to observe it. The ability to position satellites closer to Earth has unlocked new possibilities for military and intelligence operations in particular. While orbiting at this altitude came with engineering challenges to overcome, the fruits of R&D labor are now being realized. However, VLEO is not truly a new domain.

Among the U.S.’s early foray into space-based reconnaissance during the Cold War era was the Corona satellite program. In 1960, an Air Force U-2 spy plane was shot down by a surface-to-air missile while collecting imagery over the Soviet Union, accelerating U.S. plans to begin collecting overhead imagery from satellites instead of planes. Launched throughout the 1960s and early 1970s, Corona was a family of strategic reconnaissance satellites procured and operated by the CIA in collaboration with the Air Force. These satellites were in fact modified Agena rocket upper stages equipped with cameras which flew at VLEO altitudes — commonly below 150 km. At this time digital cameras did not exist, so film would be jettisoned back to Earth in Satellite Return Vehicles, which were then recovered and processed by intelligence analysts in the U.S. While a novel approach to VLEO at the time, turning rockets into satellites is not practical today.

In recent years, the U.S. (including several domestic companies and labs such as the MIT Lincoln Laboratory), the European Union, Japan, and China have all been pursuing modern VLEO demonstrations. Key advancements have enabled VLEO satellites in the following areas: electric propulsion, navigation, on-board computing, and low cost digital imagery. Some modern VLEO missions of note have been the European Space Agency’s Gravity Field and Steady-State Ocean Circulation Explorer, which was operational from March 2009 until November 2013. It was designed to map Earth’s gravity while operating at an altitude of about 255 km. Next, in 2017, Japan’s JAXA flew its Super Low Altitude Test Satellite which carried sensors and a camera. It completed its mission in 2019. More recently, the European Space Agency awarded the Skimsat program to Thales Alenia Space and Redwire, which aims to reduce the cost of Earth observations by operating in VLEO.

Due to these advancements and demonstrations, national security missions will soon be able to use VLEO to unlock higher resolution imagery while also reducing cost. Cost can be reduced by using smaller launchers; using commercially available cameras which don’t require the radiation hardened electronics necessary for operation in higher orbits; and by not requiring large optics to make up for the higher altitudes of LEO. But operating in VLEO isn’t just about higher resolution and cost savings, it also presents a unique mitigation to the growing threat of space debris in LEO.

Debris and discarded stages from a rapidly growing count of commercial launches contributes to the problem of orbital debris. Perhaps the most poignant example was Russia’s anti-satellite missile test. In a reckless act on Nov. 15, 2021, Russia fired a missile into space, targeting and destroying its own satellite, creating a cloud of debris that later threatened the lives of astronauts (and Russian cosmonauts) aboard the International Space Station. As we know in the industry, and many casual space fans learned through the film Gravity, colliding objects in LEO can cause cascading chain reactions. The cloud of debris in LEO orbits may persist for a decade or more. However, VLEO is self-cleaning. Debris and unpropelled satellites naturally reenter Earth’s upper atmosphere and safely disintegrate, typically in a matter of days, thereby significantly reducing the risk to other operational VLEO satellites.

Near peer competitors have also seen the benefits of VLEO and have begun programs to take advantage of the domain. The China Aerospace Science and Industry Corporation, a key player in China’s defense sector, has announced plans to deploy a constellation of VLEO satellites. These satellites, orbiting at altitudes between 150 and 300 kilometers, represent a significant step in China’s ambition to bolster its remote sensing capabilities, promising higher resolution imaging and faster data transmission. 

General James Dickinson, the former Commander of the United States Space Command, published his strategic vision in 2021 titled “Never a Day Without Space,” which highlights that “our competitors seek to prevent our unfettered access to space and deny our freedom to operate in space.” As discussed, the value VLEO offers to the U.S. and its allies is too great to lose. The combination of high-resolution imagery, innovative propulsion systems, and the sustainability aspect of VLEO operations positions it as a crucial domain in the future of defense and intelligence operations. As these developments unfold, VLEO is poised to play a pivotal role in shaping the dynamics of space-based defense strategy.

Spence Wise is Senior Vice President, Missions and Platforms at Redwire Corporation, a global space infrastructure and innovation company enabling civil, commercial, and national security programs. Spence has spent more than 15 years developing, commercializing, and advocating for innovative space technologies and architectures to support critical national security missions.

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