With the United States moving toward fielding “massive multi-satellite constellation” architectures for national security missions, a radical change in the strategic calculus associated with space defense and space superiority is required. While many aspects of natural defenses of massive multi-satellite constellation architectures have been presented by U.S. government advocates such as the Space Development Agency, acquisition executives and strategic thinkers must consider additional factors for potential vulnerabilities and some potentially non-intuitive strategic impacts. This paper begins to address some of the national security strategic considerations of massive constellation architectures and suggests areas of future study.
*MMSC - "Massive Multi-Satellite Constellation"
U.S. Department of Defense public statements and wargaming reports have shown a major topic of concern over the past decade and a half is how U.S. on-orbit constellations can operate through the spectrum of conflict.[i] A possible solution to maintaining mission during space conflict is to provide resiliency through the distribution of effect and disaggregation of assets. Until recently, large constellations of satellites in orbital shells or swarms were cost-prohibitive, but the reduction in launch costs per satellite and satellite construction costs enabled by small satellite (smallsat) engineering advances have changed the legacy paradigm.[ii] Multiple government elements of the national security space (NSS) community have embraced this concept through massive “multi-satellite constellation” architectures for future mission areas.[iii]Most notably, the Space Development Agency (SDA) has advanced the ideas of multiple mission layers to enable next-generation missile warning, communications, and navigation services in support of terrestrial force utilization.[iv]There are varied motivations in moving toward these radically different NSS architectures. They range from cost factors such as lowered cost-per-pound to orbit launch costs, to defense factors such as inherent protection of mission capability despite potential loss of individual assets.
Massive constellation architectures do have some natural defenses against deployed and in development anti-satellite weapons (ASAT). However, do these massive constellation architectures have some inherent vulnerabilities? A crucial aspect in examining the risk/reward calculus of these new architectures is a consideration of whether these assumed inherent defenses and potential vulnerabilities introduce a new series of strategic impacts on space warfare that change U.S. and allied paradigms of space warfare.
What are Massive Multi-Satellite Constellation?
This paper defines multi-satellite constellations (MMSCs) as singular mission-based constellations ranging from dozens to hundreds to thousands of individual smallsats (< 1000 kg mass) units operating in a similar orbital regime. This definition can be applied to more than military utility-based missions - Planet’s Dove imaging satellite constellation, the projected SpaceX Starlink and OneWeb communication satellite constellations, and Spire's commercial weather / radio frequency-based remote sensing satellite constellation are all examples of MMSCs built for commercial or non-defense-based customer bases.[v] In the NSS mission space, the SDA’s architecture of new missile sensing/launch warning, crosslink enabled communication, and alternate precision, navigation, and timing (PNT) constellations are the prime examples of this concept of MMSCs. The SDA is developing these missions in what they call “tranches” to take advantage of both economies of scale in developing large quantity manufacturing of interoperable satellites, and to increase the technology refresh rate by planning for obsolescence with frequent replacement launches. Each mission layer is expected to be comprised of “shells” of orbit planes of similar altitude but differing inclinations and spacing of satellites.[vi]Other government NSS users are exploring this innovative mission architecture, to include the Missile Defense Agency (MDA) with their Hypersonic & Ballistic Tracking Space System (HBTSS, pronounced “Hobbits”) constellation, and the U.S. Space Force (USSF) discussing next-generation weather satellites to be based on MMSC architecture. Even if these concepts do not come to fruition, there is momentum moving toward this type of architecture, exemplified by the then – U.S. Strategic Command commander General John Hyten’s statement: “I won’t support the development any further of large, big, fat, juicy targets.”[vii]
Current U.S. NSS capabilities are under threat
Russia, China, and Iran have all conducted anti-satellite operations over the past ten years, indicating a desire to field counter-space capabilities that could target United States and its key ally/partner space capabilities.[viii] The United States and international partners have a asymmetric advantages in terrestrial warfighting, in particular naval operations and expeditionary warfighting.[ix]PNT services allow the employment of precision-guided munitions from standoff ranges executing precise, targeted strikes against remote adversaries with minimal collateral damage. Worldwide communication connectivity through survivable and protected satellite communications (SATCOM), enabled by flagship military and commercial communication satellites in geostationary orbit, has given the United States and its allied forces unprecedented ability to coordinate military movements and establish global reach. This global reach is evidenced through traditional force build-up, newer weapon systems such as unmanned aerial systems / vehicles (UAS/V), and newer, highly efficient concepts in joint all domain command and control (JADC2) bringing forces to bear in shorter, ever more lethal, battle rhythm cycles. Strategic and operational-level military surprise by conventional terrestrial forces have been rendered all but non-existent due to space-based remote sensing systems - from national intelligence collection platforms such as those operated by the National Reconnaissance Office (NRO) to more tactical support systems such as the Space Based Infrared System (SBIRS) sensor network that feed missile defense systems. Through all these mission tapestries, one thread remains common: these missions are based on exquisite, large, highly capable, lumbering, expensive, fragile, and slow to replace space platforms. This makes them inherently and simultaneously both the United States’ Zeus-ian Lightning Bolt and Achilles’ Heel. In theory, loss of a single asset in these mission architectures could degrade or even disable local, if not theater-wide terrestrial warfighting advantages.
Primary motivation in moving toward the deployment of MMSCs is an inherent realization that these new architectures have natural defenses against many current and near-term counter space capabilities in development by potential adversaries. From the perspective of the space-based kill chain, MMSCs complicate the adversary's ability to perform the necessary find, fix, track, target, engage, and assess by disaggregating capabilities and stressing their space domain awareness capacity. [x] Core to this advantage for the MMSC operator is that a loss of one or more units of the MMSC may not kill the mission of the constellation if the additional satellites in the constellation provide either overlap or resiliency to the capabilities of a single asset. The mental picture easiest to envision is a fabric, where a tear or hole in one area of the fabric does not destroy the entire item. MMSCs mitigate adversary counter space capabilities that may be magazine depth limited (either in number or temporal utility) such as direct ascent interceptors or exquisite orbital anti-satellite systems. For counter space systems that have high revisit rates against single satellites, like narrowband radio frequency jammers or ground-based laser systems, the associated targeting algorithms may be overwhelmed by the swarm of targets coming over the horizon. MMSCs change the cost equation for adversaries developing counter space systems attempting to neuter traditional NSS platforms, which tend to be the “big juicy targets” referenced earlier by General Hyten. If successful, MMSCs could even deter adversaries from investing in certain counter space capabilities. While there are many defensive advantages from the deployment of MMSCs, one has to consider whether there are additional vulnerabilities.
First, the number of satellites deployed in similar orbit shells brings the threat of cascading debris generation as a result of a successful kinetic strike, a phenomenon commonly referred to as "Kessler Syndrome," named after Donald Kessler.[xi] While the probability of irreversible cascading of serial debris strikes is debated, a series of successful strikes against multiple units in an MMSC could cause debris generation that will necessitate orbital maneuvers of multiple assets to avoid potential collisions, and will, at the very least, complicate command and control (C2) of the MMSC as the debris propagation is observed and analyzed.[xii]This has already been witnessed in a smaller scale following the 2007 Chinese ASAT test, where the International Space Station conducted maneuvers to avoid debris from the ASAT objects.[xiii]
Second, the number of satellites operational within one of the proposed MMSC orbits, much less multiple of them operated by the same service or organization, is going to necessitate additional autonomous operations via artificial intelligence and inter-satellite mesh-enabled links to pass command and payload data between individual units. The numbers of units operating will necessitate a complex C2 architecture at ground stations that will be reliant on networked, computer-assisted, autonomous C2 using artificial intelligence algorithms than likely any military system conceived before. Both of these aspects mean that exponential growth in potential cyber infiltration vectors will be available to enemies, and that introduces a cyber-attack perimeter that has to be defended at every ground site terminal, user workstation, deployed troop & platform aperture in the field directly communicating with the MMSC units, satellite uplink, downlink, and inter-satellite link aperture, software development factory, and supply chain access point.[xiv]
Third, the electronic warfare environment will likely change. Due to the dependence on satellite-enabled communications through the use of large geostationary positioned assets, adversaries have focused on developing ground-based jamming assets that target the communication payloads on the satellites themselves, since they are a relatively stable target.[xv]Satellite developers have countered with electronically steered and segmented beams from the satellites to the ground user areas and complex “anti-jam” waveforms.[xvi]Developers and adversaries continue the cat and mouse game in attack and defense development for these flagship geostationary satellites, but the MMSC communication architecture threatens to upset that balance by introducing a huge number of overhead apertures that users can access at variable geometries and degrees of overlap, overwhelming the ability of the adversary to field enough ground-based jammers with enough agility to effectively deny all communications. Since these MMSC communication satellites will likely have less power transmitted and available onboard compared to their geostationary brethren, from a vulnerability perspective, we may see a return to wide-area terrestrial jamming of user terminals with the tower located or high-altitude airship jammers. While in the past these types of wide-area user jammers have themselves become beacon targets for a terrestrial strike, anti-access area denial capabilities enabled by adversary developments in air defense network sensors and counter weapons may make it more difficult to neutralize them. Other types of counter-counter electronic warfare capabilities employed may complicate the electronic warfare environment, including the potential of greater inadvertent interference events.
MMSC Drive Paradigm Shifts in Strategy, Acquisition, and Operations
In consideration of the natural defenses of MMSCs and the vulnerability environment of MMSC employment, there are a few novel strategic impacts to the existing space warfare paradigm. These impacts are in some cases increased concern for an existing strategic consideration, but in others introduce a new paradigm to analyze novel strategic impacts to the existing space warfare paradigm. These impacts are in some cases increased concern for an existing strategic consideration, but in others introduce a new paradigm to analyze.
From a strategic perspective, demand for resilient and distributed launch capacity is a key architecture requirement for any MMSC. Implied in the natural defense and cost calculus of the MMSC based architecture is the ability to rapidly launch evolutionary, augmenting, or replacement units in large enough quantities to maintain the mission of the architecture. The U.S. MMSC architecture is reliant on the long lead-time, multi-satellite deployment events from singular, large space launch vehicles at one of two spaceports: the Cape Canaveral complex in Florida and the Vandenberg Space Force Base complex in California. While both sites have multiple launch pads, they are still, for the most part, singularly geographically condensed targets, susceptible to a determined adversary attack with a weapon of mass destruction or multiple small-scale strikes on the individual launchpad complexes. Until multiple viable spaceports with a geographic diversity are established, coupled with an ability to conduct rapid space launch with a variety of launch vehicles, the United States remains vulnerable to a “Battle of Yavin” or true “Pearl Harbor” type of event.[xvii]If such a strike against the two space ports were successful, the ability of U.S. forces to replace losses in space and exercise those assumed advantages could be virtually eliminated.
Even with a retooled American satellite manufacturing base capable of producing the MMSC units in quantity and quality needed to execute the desires like what the SDA has proposed, and a cyber defense posture able to prevent or mitigate attacks at multiple nodes in the architecture, all that advantage is for naught if the United States can not get those units into space to execute those missions. The United States, to have confidence in the advantages of a MMSC based space architecture, must have continuous space launch access while absorbing the loss (even if temporary) of one or both of its existing major spaceports. This is why it is as crucial as the satellite industrial base transformation itself. The development of multiple alternative spaceports and launch vehicles as proposed by the commercial space communities in Virginia, Alaska, New Mexico, Michigan, and Colorado must come to fruition for an MMSC architecture to have viable resiliency.
Today adversaries are developing singular weapon systems to, for the most part, attack singular space targets.[xviii]Shifting to a resilient-to-single-attack MMSC based architecture reduces the utility of expensive, technically complex counter space systems, such as orbital anti-satellite, where the calculus is in favor of destroying an extremely costly high-value asset (HVA) with a less expensive but still complex weapon system in a limited deployment context. Instead, adversaries may shift the development of weapon systems away from expensive exquisite systems with limited quantities to vectors that have larger volumes of effect - debris dispersal devices or orbital altitude nuclear weapons. The desired attack effect by an adversary goes from disabling or destroying individual HVAs toward disabling or destroying missions (which may necessarily mean destroying large quantities of satellites within a short period) with weapons that previously have been considered strategically destabilizing. Even with the advent of MMSC architectures, the strategic calculation of “who has the most to lose if satellite assets are lost” is still heavily weighted against the United States, no matter the potential adversary.
However, if the United States deploys MMSC based architectures, is the need for higher quality space surveillance intelligence against singular space assets reduced in favor of sensor networks that favor higher tempo measurements providing “good enough” detail? This also applies to space surveillance capabilities. Potential adversaries are developing contemporary space surveillance sensors that will provide the accuracy and higher detail characterization information needed to exquisitely target high-value assets, both for high accuracy location information needed to precisely target weapon systems, but also to potentially perform combat identification in situ of the attacking operation.
If wider area, less discriminate weapon systems are deployed to try to destroy a single or multiple string of satellites, the orbit determination requirement for that weapon system reduces from high accuracy determination of singular satellites to just figuring out where the highest density constellations are at the right altitude. This results in a much easier to apply space surveillance problem – not trying to find a single locust on a single corn stalk, but needing to identify where the locust swarm is flying. This means that the enemy can then employ space surveillance capabilities that are focused on being always on and providing as wide a “fence” as possible to develop generalizations of orbit usage, not on exquisite tracking beams using large apertures or active tracking sensors with more indications and warning of usage to the targeted units. Perhaps counterintuitively, going to a MMSC architecture by the United States may make the space surveillance job easier for the adversary, and consequently, change the risk-reward calculus for the usage of less discriminate counter space weapons options.
Finally, the question remains as to what to make of previously highly coveted geostationary orbit positions over theater areas of operations because the deployment of multiple MMSCs to form mission constellations likely means deployment at lower orbital altitudes to reduce spacecraft construction and launch costs. These positions would be assumed to reduce in importance since the traditional mission of geostationary slot satellites, part of theater stable communication and strategic missile warning remote sensing missions, would be subsumed by the near-ubiquitous coverage of overhead MMSCs. These "zenith" positions over conflict areas may, however, become valuable over time because they provide the user persistence of view. Zenith positions may also provide value as electronic warfare “assets” (disrupting lower satellite GPS receivers needed for autonomous operations based on timing signals) and as assured theater communication capacity for either regime or anti-regime forces in the theatre of conflict, using the MMSC enabled communication architecture. Alternatively, if geostationary satellites become less important and valuable over time, then perhaps heavy launch vehicles become less important, resulting in a radical change to the launch operations and economic status quo. Granted, commercial and civil space needs such as launching exploration missions and human settlement missions to the Moon or Mars still will have a need for heavy launch vehicles, but NSS missions could shift with the proliferation of MMSC.
The development of MMSC architectures by defense department entities as described above represents a radical change to the economics and tactics of national security space operations. There are, however, risks inherent in the development and deployment of MMSCs that should be weighed against the benefits of employing such systems to fully understand the value of MMSCs going forward. This new architecture concept, once dropped into the pool of military acquisition, will cause ripples affecting strategic decisions on space launch access, weapon systems development, and even strategic weapon usage thresholds. It is time to start thinking about it now.
Dr. Brandon Cesul is a Technical Fellow and Principal Space Systems Engineer at KBR, Inc. This paper represents solely the author’s views and do not necessarily represent the official policy or position of any Department or Agency of the U.S. Government. If you have a different perspective, we’d like to hear from you.
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[xvii] Commission to Assess United States National Security Space Management and Organization. 2001. “Report to the Commission to Assess United States National Security Space Management and Organization.”
[xviii] Defense Intelligence Agency. 2019. “2019 Challenges to Security in Space.
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