WASHINGTON — The Pentagon needs to invest in a new mix of space constellations and information systems in order for the United States to remain a dominant military superpower, says a study released on Thursday by a prominent Washington think tank.

In a report titled “Building the Future Force: Guaranteeing American Leadership in a Contested Environment,” the Center for a New American Security warns that the spread of advanced technologies has allowed state competitors to challenge U.S. military advantages in naval and air warfare, particularly in long-range targeting and missile defense.

The report was prompted by long-time concerns about the U.S. military’s eroding technological advantage. Forces have to be better equipped in the face of a “more aggressive Russia and the rise of a powerful China,” CNAS founder and former undersecretary of defense Michele Flournoy said at the study rollout event.

In a conflict against a peer competitor, the study said, the U.S. military will be at a disadvantage without a “resilient intelligence, surveillance and reconnaissance architecture.”

One problems is that current space and airborne sensors do not provide sufficient around-the-clock coverage, CNAS analysts argued. Low Earth orbit (LEO) satellites can spend a few hours over a target area. Drones can spend several days above a target. Satellites in geosynchronous orbit (GEO) can provide continuous coverage of designated target areas. But there are not enough GEO satellites to fully offset LEO satellites and airborne ISR limitations.

The answer is to develop lower-cost constellations. “Small satellites should make up the core of the future LEO ISR satellite network,” CNAS suggested. “These satellites range in size from .25 to 400 pounds and cost as little as $150,000.” Large military satellites by comparison cost hundreds of millions of dollars per unit.

Small satellites can be produced and launched in larger numbers. While big-ticket military satellites are far more capable, cheaper alternatives would make it possible to produce ISR constellations made up of thousands of small satellites, said the report. “Within each constellation, sets of small satellites would be assigned to perform each of the tasks previously done by single, expensive satellites. The sheer number of satellites would also allow each constellation to observe a far larger target set than previously feasible.”

The redundancy built into these constellations would complicate adversary attempts to take them down. “The number of satellites adversaries would be forced to engage to cripple U.S. ISR would be orders of magnitude greater than it is today.”

Cheap launch vehicles also should be a priority for the Defense Department, the report said. If future constellations are built with open architectures, the military could quickly replace obsolete or damaged satellites. “Rapid reconstitution of ISR constellations will require low-cost, short-notice launch capabilities.”

Another imperative would be to harden small-satellite constellations’ ground stations. Because satellites in LEO operate relatively close to the Earth’s surface, a larger number of ground stations will be required to maintain line-of-sight communication with these assets, the study said. “Adversaries may attack these stations to prevent satellites’ operators from using data collected by those assets during phases of orbit when the satellites pass over inoperable ground stations.”

A few caveats

The Pentagon will need to carefully estimate the cost of future constellations of small satellites, the study cautioned. While the per-unit price of small satellites is considerably lower, there are additional expenses to be considered such as new terrestrial communications stations and intra-constellation data-sharing systems. “That said, the operational benefits afforded by a shift toward more resilient small-satellite constellations may make even a modest increase in the cost of the U.S. military space architecture worth the added expense.”

Small satellites should make up the core of America’s LEO ISR architecture, but the future force also will need some larger, more exquisite satellites in GEO. “By virtue of their cost, these large satellites in GEO will be unable to find protection in numbers like their smaller counterparts in LEO,” said the report. The larger assets could be protected using a combination of hardening and active defense.

LEO is within 2,000 km of the Earth’s equator, while GEO is 36,000 km above it. The distance factor offers some protection, the report said. “Adversaries will require more advanced and costly missiles and directed-energy and electronic weapons to strike satellites at that range.”

The terrestrial support infrastructure for GEO satellites is less vulnerable to attacks. Satellites in GEO can see a third of the Earth at any time, and satellite ground stations can be dispersed over a larger area, thereby complicating adversary targeting, the report noted. As small-satellite technology matures, the U.S. government should re-evaluate spending on larger satellites in GEO. For now, however, GEO satellites will have a place in the U.S. military space architecture.

Beyond satellites, the United States should also invest in a new generations of airborne ISR platforms as a hedge against unanticipated vulnerabilities. These platforms may be able to fill gaps in space-based coverage.

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...