A Starcruiser for Space Force: Thinking Through the Imminent Transformation of Spacepower

May 19, 2021
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The U.S. military has launched and operated Earth-orbiting satellites since the Discoverer 1 mission in March 1959. Despite this long-term presence in space, spacepower as a mature military discipline remains in its infancy. However, change is coming faster than many expect. The X-37B spacecraft — the first true military spaceplane — foreshadows the “end of the beginning” for military space as satellites, tiny spaceplanes, and single-use orbital boosters give way to massive fleets of very large, maneuverable, and reusable spacefaring vehicles.

Rapid advances in rocketry led by private space companies mean that the U.S. military may be able to reach orbit cheaply, refuel in orbit at low cost, and use this fuel to maneuver extensively once there. These new rockets will replace the X-37B and ultimately transform how the U.S. military understands spacepower. SpaceX’s new orbital vehicle, Starship, and its booster stage, Superheavy, exemplify these new spacecraft in that they are capable of lifting huge payloads to low Earth orbit and beyond frequently and at extremely low cost. With this vehicle now flying and landing, it is not too early for the U.S. military to think through the far-reaching military implications of the emergence of Starship-class vehicles for its future joint warfighting concepts.



Numerous technical challenges remain. Starship still needs to demonstrate that it can be reused after surviving landing and it has not yet achieved orbit. Superheavy is still under construction and will not fly until summer — and even then, with only three of its planned complement of 37 engines. Core capabilities such as orbital refueling, crucial to advanced maneuver above the atmosphere and central to unlocking commercial and military space, still need to be tested. However, many were skeptical that reusable rockets would ever be commercially viable. Yet such rockets transformed the global space access landscape. SpaceX is quickly working to overcome these remaining technical obstacles as well,  recently landing Starship safely and tail first for the first time, and returning it to the pad within days for a possible second launch attempt.

Despite these very real technical hurdles, the U.S. military should start thinking through the implications of what these capabilities — once they come online — will mean for space warfare. Bringing together “impossible” full-flow staged combustion rocket engines, very large vehicles, and, most critically, the ability to refuel vehicles in orbit at or near the cost of propellant will upend the harsh and unforgiving constraints that drive America’s understanding of space operations today. As a result of this pending transformation, the military should alter its assumptions about the cost and difficulty of accessing space, and rethink space warfare in a world in which cheap space access is plentiful and the ability to maneuver in space is abundant.

Looking to the Past

How will rockets like Starship shape the future of the U.S. military? The emergence of airpower can help us think through this question. In 1909, a mere six years after the first flight, the Wright brothers demonstrated the first military aircraft, the Wright Military Flyer, to the U.S. Army Signal Corps. It carried a crew of two at less than 50 miles per hour. Although its performance barely qualified as “airpower,” it proved that powered flight was possible and sparked the first theoretical developments recognizing the importance of airpower to future warfare.

Early airpower theory far outpaced the actual performance of the aircraft of the time. The military had used balloons for artillery spotting and dirigibles for scouting and bombing for decades, but these were mostly tethered to static locations and subject to sniping from the enemy. Early fragile, kite-like flyers would soon give way to new types of aircraft that were capable of vastly superior range, payload, and speed. Less than 20 years after the Wrights’ demonstration, the iconic Douglas DC-3 flew for the first time. This aircraft and others like it would revolutionize the commercial use of the air, outclassing the Wright Flyer in every way. Carrying up to 28 passengers at a time, the DC-3 cut the cost of flight and was widely regarded as “the first airliner capable of making money by just carrying passengers.

This new transportation market was instrumental in expanding America’s use of the air for commerce and transportation. Additionally, the DC-3 design was a model for the wide array of military aircraft that would soon be produced in large numbers. All-metal construction, retractable landing gear, high-powered engines, long range, and the ability to mass produce and service them revolutionized airpower and allowed the United States to dominate the air in the World War II.

A revolution in rocket technology is on the cusp of transforming spacepower much as the DC-3 transformed the art of the possible in airpower. These technologies include extremely powerful full-flow staged combustion rocket engines; reusable first-stage boosters; returnable, aircraft-like space maneuvering vehicles; and on-orbit refueling. While these cutting-edge technologies are still maturing, in time they will allow for much larger, more capable and more maneuverable space vehicles to operate there far more frequently and on a sustained basis than is now possible. A U.S. Space Force that takes full advantage of these vehicles will outclass its competitors by  allowing it to place massive payloads into orbit on a daily or hourly basis, changing orbits frequently, and doing so over long periods of time, as well as expanding its ability to establish a presence throughout the Earth-Moon system and beyond.

Enter the X-37B

If satellites — confined to relatively static orbits, fragile, and highly vulnerable to enemy action — are a rough analog for balloon-based airpower prior to the World War I, then the U.S. Space Force’s X-37B plays the role of the Wright Flyer. The X-37B is an orbital test vehicle designed to develop and demonstrate a wide range of long-duration space technologies. It is capable of hosting experiments in its small payload bay, remaining in orbit for months and years at a time, and returning its test items to Earth for further examination — a capability the United States largely lost since the end of the shuttle program. The small craft is launched atop legacy expendable rockets such as the Atlas V or the more advanced, reusable Falcon 9 booster.

Upon reaching altitudes of between 110 and 500 miles, the X-37B begins operations in orbit. Today, for example, it is hosting groundbreaking power beaming experiments that are critical for clean, space-based solar energy generating stations to power the Earth’s electrical grid. What truly sets the X-37B apart is its apparent ability to conduct large changes in its orbit and to do so far more frequently than today’s satellites. Satellite operators are usually reluctant to make dramatic orbital adjustments of any kind because most satellites cannot yet be refueled in orbit. This makes most satellites highly predictable and, for military systems in particular, vulnerable to attack.

The ability to maneuver in space is known as delta-v, a measure of the total change in velocity needed to move between different orbits, locations, or objects in space. Thinking in terms of delta-v, rather than distance or speed, is what truly sets space operations apart from land, sea, or air operations. As science fiction author and futurist Daniel Suarez put it:

Delta-v is fundamental to space exploration. It’s the amount of energy [needed] to provide an impulse to achieve a trajectory to reach something, because everything is in motion in our solar system and in our universe.

The X-37B conducts orbital maneuvers and its deorbit burn with its single Rocketdyne AR2-3 engine that provides it, in principle, substantially greater delta-v than today’s satellites, allowing it to make the timing and location of its orbital movements more unpredictable and difficult to track. As former Secretary of the Air Force Heather Wilson noted, “our adversaries don’t know… where it’s going to come up next. And we know that that drives them nuts.”

Although the X-37B appears to have the capacity to conduct higher delta-v maneuvers relative to traditional satellites, its spacefaring capabilities remain rudimentary at best. It is only 29 feet long with a diminutive, seven-by-four-foot payload bay — smaller than a pickup truck bed. It is also extremely costly, able to carry up to 3,000 pounds into space at a total cost of between $60 million and $110 million, which translates to an eye-watering $2,500 to $5,400 per pound. The entire force currently consists of only two vehicles, only marginally improving the aggregate delta-v available to the U.S. space fleet.

The X-37B provides the first hints of the potential of orbital maneuver. The spaceplane’s rudimentary ability to conduct more unpredictable and dynamic operations suggests the significant strategic and military advantages of more capable, cheap, and responsive spacecraft. The next U.S. spaceplane must not, however, incrementally improve on the X-37B but should take a massive and transformational leap that recalls the distance between the Wright Flyer and the DC-3.

Starship: Delta-V on an Unprecedented Scale — and Much, Much More

Starship is quite unlike any rocket that has come before it. When operational, its size, payload capacity, and ability to land and fly again as well as the number of vehicles that will be constructed will eclipse anything built over the past 70 years of spaceflight.

Starship has conducted four test flights, with many more on the way. This is well in advance of other heavy lift rockets on the test stands and drawing boards of its competitors. Unmanned orbital flights may commence as early as 2021 and private manned flights around the Moon as early as 2022. SpaceX recently won the National Aeronautics and Space Administration contract to provide lunar landing services with a lunar variant of Starship. The company also plans unmanned flight tests to Mars as early as 2024.


Source: Generated by author (Image from Giuseppe De Chiara 1968, data from SpaceX)

The dimensions of Starship are staggering. The 164-foot-tall vehicle is itself only the second stage of a much larger two-stage rocket. Together, Starship and the Superheavy booster will stand some 400 feet when fully stacked — taller than a 28-story building and only 100 feet shorter than an Arleigh Burke-class destroyer. The Superheavy’s 37 highly advanced, methane/liquid oxygen-fueled Raptor engines provide well over twice the thrust of the Saturn V that first placed Americans on the Moon, making Starship (at least for the next several months) the most powerful rocket ever to have flown.

Starship will operate in deep space powered by six of the same Raptor engines, several of which are optimized for more efficient delta-v in orbit. The use of many common, mass-produced engines for both stages contrasts with Saturn V’s 11 hand-built engines of differing types, contributing to Starship’s low launch costs and allowing missions to continue even if an engine fails in flight.

At just over 56 feet long, Starship’s payload bay also dwarfs that of the X-37B: Three or more entire X-37Bs — or a complete 1970s-era lunar command module — would fit within this space with room to spare. The company will use this cavernous space to carry a wide range of payloads weighing up to 60 tons to low Earth orbit, nearly 100 times the estimated capacity of the X-37B. When it arrives, a single Starship/Superheavy will be able to place more mass in orbit during a single launch than the entire world managed in total in 2020.

Starship/Superheavy will be fully reusable, unlike any other rocket flying today. The Superheavy booster will, like SpaceX’s current fleet of Falcon 9 first stages, return to the launch site. Unlike Falcon 9, however, Superheavy may be caught by the launch tower, stacked with a new Starship, refueled, and launched again in days or even hours. SpaceX intends to fly Starship at a per-mission cost of $2 million. If achieved, this will mean a Starship tlaunch will cost less than one one-thousandths that of the nearest equivalent rocket under development, NASA’s space launch system rocket.

SpaceX envisions building as many as 1,000 Starships, consisting of different variants. These will include a cargo version, a manned spacecraft for orbital or deep-space missions, and the aforementioned lunar lander. Perhaps most importantly, the company plans a tanker version to refuel cargo and manned Starships in space at $2-$5 million per launch. For comparison, 13 Saturn-V rockets were flown over the course of its lifetime, while the five partially reusable space shuttles flew a total of 135 missions. Starship production and flight will be more akin to the operation of wide-body aircraft, which typically number in the thousands, than past rockets.

Finally, the delta-v available to a Starship refueled in low Earth orbit is expected to be some 6,500 meters per second. This dwarfs that of a typical satellite, which can range from 50 to 100 meters per second per year. This large delta-v budget increases the range of the spacecraft to the surface of Mars after refueling in low Earth orbit.

The importance of Starship’s organic orbital refueling capability cannot be overstated. Accepting eventual launch costs of between $2 million and $10 million per flight and the feasibility of on-orbit propellant transfer, a single Starship could replace a dozen or more Falcon Heavy launches that cost $150 million each today, dropping the cost of fuel, and thus the scarcity of on-orbit delta-v, by three full orders of magnitude.

This release from delta-v scarcity will allow the maneuvering of Starships almost at will when compared to current satellites or the X-37B. Instead of being decommissioned, an empty Starship can simply rendezvous with one of the (potentially many) tanker variants and return to station, much as most U.S. military aircraft do today — but in this case, throughout the entire Earth-Moon system and other strategically significant locations in the solar system.

This massive increase in surplus maneuver capacity across the Space Force orbital fleet can allow for more flexible, secure, and expansive space operations throughout cislunar space and beyond. SpaceX plans to use Starship’s unparalleled capabilities for a wide range of applications, from enabling a sustainable colony on Mars to, more prosaically, launching as many as 400 of its Starlink satellites at a time as it builds out its full constellation of 30,000 individual satellites. The U.S. Space Force could leverage this capability to quickly build out its own massive constellations or to develop and deploy entirely new, highly capable spacecraft of its own to conduct emerging missions to geosynchronous orbit and to lunar distances and beyond. Because Starship/Superheavy will be able to place some 21 tons into much-higher and highly strategic geosynchronous Earth orbit, Space Force can dramatically increase its ability to operate in this location where the X-37B cannot reach.

A Starcruiser for a Spacefaring Nation

The X-37B represents the first fitful steps toward a true space-going U.S. Space Force. Currently, U.S. operations in space remain heavily constrained by relatively scarce delta-v and a similarly cramped and constrained view of what space operations can truly be. This limitation is baked into current space thinking. As articulated in the 2020 Space Capstone Doctrine, Spacepower:

Constrained freedom of maneuver is a defining attribute of space operations. … Due to extreme velocities, the amount of energy required to reach a different orbit may be significant enough to render the option unfeasible or impractical.

In a world in which Starship-class vehicles exist, and exist in great numbers, new and very different kinds of space operations become feasible and practical. With space threats multiplying and the military, scientific, economic, and industrial importance of space set to explode, the U.S. Space Force will need spacecraft capable of keeping pace with the state-of-the-art spacefaring capabilities the commercial sector is very close to deploying.

The scale of economic activity that space adds to the terrestrial economy is already worth almost $500 billion per year. Based on old rocket technology alone, it is set to grow into a potential trillion-dollar industry including communications technology, tourism, mineral wealth, and cheap, environmentally friendly sources of renewable energy for the benefit of everyone on Earth. Starship-type vehicles will supercharge this economic activity and make space development a critical aspect of many nations’ aggregate strategic power. History also suggests that conflict and war will also follow us into space and that strategic rivalry, competition, and war both in and about space are more than likely inevitable.

In this vastly expanded competitive domain, the U.S. Space Force should work closely with SpaceX and other, similar launch providers to take advantage of the cost-effective, sustained access to space that new rockets like Starship will provide. It should focus on launching large reserves of fuel into orbit and the capacity to transfer fuel to all space assets in orbit to support continual maneuver across the orbital fleet. Starship and the growing space-mindedness these types of space vessels will encourage suggest a future battlespace dwarfing the 1,000 to 2,000-mile ranges that are typical of modern ballistic and cruise missiles and A2/AD bubbles that define much modern thinking about future war.

The vast majority of U.S. strategic and military thinkers have not conceptually adapted to a battlespace that stretches across the entire Earth-Moon system and the fluid maneuvers among orbits that could occur. To operate across this vast area, we should change our working analogy from the air domain to the sustained actions that occur over the maritime environment. In naval terms, a cruiser is a “large warship built for high speed and great cruising radius, capable of not only defending its own fleet and coastlines, but also threatening those of the enemy.” A Starship-based vehicle — call it a “starcruiser” — represents a new class of space operations vehicle that would be built for sustained manned and unmanned operations in space and provide high delta-v, capable not only of defending itself and its orbital patrol area but also of credibly threatening the orbital assets and operations of the enemy.

A force capable of operating starcruisers across these vast spaces will be far more than an auxiliary support to forces on Earth. It will be a force with its own and often independent deterrent and coercive capabilities. Recognizing and seizing the opportunity today mean the difference between leadership and even military dominance in orbit. Today, military space strategy has not yet assimilated the implications of heavy, reusable rocket technology. While this technology is still some way off, the strategic implications for the Space Force are so significant that analysts should already be thinking through its consequences for spacepower and U.S. national security. The explosive pace of technological change coming from private space companies — in particular, SpaceX and its unparalleled achievements in lowering the cost of reaching orbit and maneuvering once there — points to the need for a more expansive vision for the U.S. Space Force, one that takes it far beyond the current force of low delta-v satellites and tiny, expensive orbital spaceplanes.



Jeff Becker is a consultant to the U.S. Joint Staff J7, Joint Futures and Concepts. The views expressed here are the author’s alone and do not represent the official policy or position of the Joint Staff, the Department of Defense, or the U.S. government.

The author would like to personally thank Tim Dodd, aka “Everyday Astronaut,” and Andy Law, whose web and YouTube pages are essential for any space enthusiast. This article relies heavily on his analysis, commentary, and graphics. 

Image: Air Force (Photo by Senior Airman Timothy Kirchner)