How Would Satellites Battle in Space?

We asked Dr. Rebecca Reesman, Senior Project Engineer and author of the paper, The Physics of Space War, to answer our questions about what’s fact or fiction when it comes to space warfighting.

Let’s talk about starcruisers. How realistic are popular sci-fi depictions of military space operations?

Sci-fi depictions, while fun to watch on the big screen, are not representative of what is possible in Earth’s orbit. The starcruiser concept is an extension of what combat can look like in the air domain, but it is not possible in space. All spacecraft or satellites are constantly moving, orbiting earth in an elliptical shape, not moving in straight lines as shown in movies. The concept of a spacecraft chasing another spacecraft would be more like a slow dance in space.

It’s going to be a while for starcruisers.

What are the limiting factors for in-space warfighting?

Orbital dynamics, which dictates how things move in space, is very different from what we know and experience on Earth. These physics realities can feel like constraints — predictable orbit paths, speed being tied to altitude, slow maneuvers. The biggest constraint in space is probably the limitation on energy, which equates to changes in velocity (delta-v).

Currently, satellites are launched with all the fuel they will ever have. That is like never being able to refuel your car, airplane, or ship, which limits the number of maneuvers you can do. While there have been advancements in energy sources and discussions of on-orbit fuel depots — which would greatly help — it’s important to remember that space is very big. Even with improved efficiency of energy sources and increased number and location of possible refueling depots, the vastness of space would still impose limitations.

A satellite is designed with a specific limitation on energy expenditure, or ∆V budget, that acts as the satellite’s fuel gauge. A satellite operator will plan maneuvers based on how much ∆V is left in the satellite’s budget.

What physical and technological challenges would have to be overcome for a sci-fi version of a space battle to be possible?

If you want to “defy” orbital dynamics to force a spacecraft to move in a straight line, you’ll need tens of thousands, or even millions, of meters per second of delta-v. This is orders of magnitude beyond what is currently possible. If we did have that kind of energy available today, the forces generated by acceleration would break apart the spacecraft.

Any space power strategy should work with — not against — those realities. Policymakers and defense strategists must continue to have a realistic understanding of what is possible and practical. A strategy that works in air, land, or maritime domains won’t necessarily work in the space domain.

We have a whole branch of the U.S. military dedicated to space defense. What does Space Force do if we don’t engage physically in space?

The U.S. Space Force provides space-based capabilities to warfighters on land, in the air, and at sea, while also ensuring that we have unconstrained access to move into and through the space domain. The USSF provides defense of space-based capabilities against a variety of threats including kinetic, laser, RF interference/jamming, and cyber. Space plays an invaluable role in all national security missions, as well as the day to day life of everyone on the planet, through GPS, communications satellites, weather satellites, financial services and more.

There does not have to be an all-out shooting war for space to be contested. Anti-satellite weapon tests have been happening for decades, including the November 2021 test that destroyed an inactive Russian satellite.

Non-kinetic threats such as jamming and lasing pose a significant risk to warfighter ground operations and have also been happening for decades. Ensuring that space systems can deliver the needed capabilities despite those threats is paramount to national security.

What would a war in space most likely look like?

A space-to-space battle would develop in a relatively slow and deliberate manner. Timing the intersection of different orbits and when certain maneuvers would need to happen requires a high-level of precision. Movements and pre-positioning would likely happen weeks to months in advance.

Kinetic weapons lead to the creation of space debris fields, which does not discriminate based on the ownership of a satellite. Consequently, a full out kinetic fight could lead to many orbits becoming inoperable for years, decades, or even centuries, impacting commercial and government owner/operators alike.

If actors want to better preserve the space environment, then non-kinetic weapons will continue to be favored. A more practical strategy is to render sensors on satellites temporarily or permanently inoperable. This can lead to devastating effects for those relying on the satellite capability, but it doesn’t make for a particularly interesting fight scene.

Learn more about the orbital dynamics of a war in space.

How likely is it that we will see global conflict erupt in a space domain battlefield?

I guess that depends on your definition of a “global conflict.” U.S. space assets are under threat from other spacefaring nations, including jamming methods to disrupt satellites, but thankfully we are prepared.

However, if you’re looking for a Star Wars-style space battle, you’ll be waiting a while…

Interested in reading more? Dr. Reesman’s The Physics of Space War is available from the Aerospace Center for Space Policy and Strategy.

Dr. Rebecca Reesman is a senior project engineer and policy analyst at The Aerospace Corporation. She provides technical support to the headquarters of the United States Space Force. She is also a policy analyst at Aerospace’s Center for Space Policy and Strategy.

Before joining Aerospace in 2017, Reesman was an American Institute of Physics Congressional Fellow working space, cybersecurity, and other technical issues for a member of Congress. Prior to the fellowship, she was a research scientist at the Center for Naval Analyses, designing, executing, and analyzing wargames.



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The Aerospace Corporation

The Aerospace Corporation

We operate the only federally funded research and development center (FFRDC) committed exclusively to the space enterprise.