An artist’s depiction of L3Harris’ tracking layer satellite, which will be part of a solution designed by the Space Development Agency and the Missile Defense Agency to track and target hypersonic weapons from space. Image: L3Harris

The US has announced plans to spend US$1.3 billion on the development of advanced satellites designed to track hypersonic weapons, a move that underscores Washington’s rising concern about China and Russia’s hypersonic threats.

According to Derek Tournear, director of the Space Development Agency (SDA), the US does not operate satellites designed to monitor hypersonic weapons, stating “we have limited capability to do that tracking aspect,” and “clearly, we don’t have zero capability to do tracking,” as quoted in the South China Morning Post.

However, Tournear mentioned that the US’ new satellites would enable it to detect and track hypersonic missiles, predict where they are headed, and provide data to friendly forces to launch interceptor missiles.

C4ISTAR reports that L3Harris Technologies and Northrop Grumman Strategic Space Systems are the primary contractors for the project. Both defense contractors are producing prototype 14 satellites for the Tranche 1 Tracking Layer, which will eventually consist of hundreds of satellites in a low-earth orbit (LEO) constellation.

As mentioned in the South China Morning Post, Tournear notes that this project represents a fundamental shift in America’s space-based missile defense sensor architecture. US space-based missile defense sensors rely on a few large, expensive satellites that stay in orbit for 15 or more years.

The US aims to replace this legacy architecture with a two-tiered system operating in low-earth (LEO) orbit at 1,000 kilometers and medium-earth orbit (MEO) at 10,000 to 20,000 kilometers using cheaper satellites that are replaceable every five years. He also mentioned that a batch of 54 satellites will likely follow the first 28 satellites of the US’ new missile defense satellites.

A June 2022 study by the US Mitchell Institute notes China and Russia’s advances in hypersonic and anti-satellite weapons and mentions that current US space-based sensors lack defenses against these threats because they are locked in predictable orbits, which increases their vulnerability.

As previously covered in Asia Times, China is developing sophisticated anti-satellite weapons such as AI-powered hunter-killer satellites capable of deception maneuvers to capture enemy satellites and satellite-mounted directed energy weapons such as lasers and high-powered microwaves that aim to burn out enemy satellites.

Artist’s illustration of a satellite under attack by a directed-energy weapon. Photo: Facebook / Defense One

In addition, The Space Review reported this month that Russia is developing a new ground-based anti-satellite laser at its space observation center in the Northern Caucasus. The weapon, known as Kalina, is designed to blind the optical sensors of enemy satellites passing over Russian territory.

The same source also noted that Russia is developing satellite-mounted lasers designed to burn out the seeker heads of incoming anti-satellite missiles but may be adopted for offensive use against other satellites.

Given these threats, the Mitchell Institute study recommends that a new US space-based missile defense sensor network must provide persistent warning and precise tracking for ballistic and hypersonic threats while at the same time mounting defensive measures such as onboard defensive weapons with maneuver capabilities and decoys.

It also mentions that the US must use technologies to increase the maneuverability of satellites to increase their survivability, evade threats and fill in sensor coverage gaps in a post-anti-satellite attack scenario.

Asia Times has previously reported on US plans to use nuclear thermal propulsion in its satellites, giving them maneuver capabilities to confound enemy targeting, increase their operational flexibility for offensive and defensive operations, and evade anti-satellite weapons.

These threats and technological advances will likely be factored into any planned US missile defense system against hypersonics. For example, a February 2022 report by the Center for Strategic and International Studies (CSIS) think tank mentions that the US Missile Defense Agency (MDA) and SDA are developing several space-based sensors to track hypersonic weapons.

The report describes a two-tier early warning system against hypersonic weapons. The first tier of this system, called the Tracking Layer, is being developed by the MDA. It employs a constellation of wide-field-of-view sensor satellites in LEO to warn against hypersonic weapons launches.

Simultaneously, the SDA is developing the second tier called the Hypersonic and Ballistic Tracking Space Sensor (HBTSS) satellite constellation in MEO, capable of high-fidelity and latency performance to support hypersonic interception missions.

This early warning system against hypersonics would rely on a minimum of 50 small satellites to reduce unit cost while having proliferation and redundancy to provide resilience against anti-satellite attacks. Apart from proliferation, the report also mentions deploying additional sensors in MEO to further confound adversary anti-satellite warfare efforts.

The two-tiered system works by detecting hypersonics within LEO while maintaining track of hypersonic glide vehicles to relay targeting data to interceptor systems.

In an Air Force Magazine article, Tourney mentions that LEO satellites can track the heat signature of hypersonic weapons during their launch and that of HGVs as they maneuver towards their targets. Thus, the LEO-level Tracking Layer will be the primary system to detect and track hypersonics during their initial launch, glide, and terminal phases, which happen within the atmosphere.

The HBTSS detects the launch and separation of the first and second stages of a hypersonic weapon’s motors, continuously relaying satellite data to track hypersonic glide vehicles (HGV) to interceptor systems such as the Aegis shipboard missile defense system, as stated by Seapower Magazine.

However, the SM-6 Standard missile, the Aegis system’s latest interceptor, may be insufficient against hypersonic threats. US Vice Admiral Jon Hill stated in The Warzone that the SM-6 is the only weapon in the US arsenal that has some capability to take on such threats and described the missile’s capability as “nascent,” implying that it has only marginal interception capability against hypersonics.

The limitations of the SM-6 may have spurred the US to develop hypersonic interceptor missiles. reports that the MDA has awarded $60 million worth of contracts to Northrop Grumman and Raytheon to develop prototypes of a Glide Phase Interceptor (GPI), a next-generation interceptor missile against hypersonics.

As quoted in the same source, Northrop Grumman says that the GPI will ensure that the US can outpace and defeat evolving missile threats. At the same time, Raytheon stated that they would use digital engineering tools and build on existing technologies for faster and cost-efficient development.

The CSIS report also notes the limitations of an LEO/MEO-based satellite constellation for defense against hypersonic weapons.

Smaller satellites possess less power generation capability to mount more sophisticated sensors and communications equipment for hypersonic weapons tracking. Also, integrating sensor data from multiple satellites in different orbits will require parallel advances in satellite communications technology, signal processing and edge computing to reduce reliance on vulnerable terrestrial data centers.

Despite US advances in hypersonic weapons and defenses, it is unclear whether the US has a coherent strategy to defend against these new weapons or a sound rationale to research defensive technologies. A 2021 US Congressional Research Service report asks whether the acceleration of hypersonic weapons research, enabling technologies and defense options are necessary or even feasible.

A test launch of Russia’s Tsirkon hypersonic missile. Image: Twitter

Hypersonic weapons may not be the game-changing weapons they are touted to be. In a Royal United Services Institute (RUSI) article, senior analyst Dominika Kunertova notes that the military effectiveness and reliability of hypersonics are still unknown, that policymakers tend to exaggerate the capabilities of hypersonics and that the race to develop such weapons seems to be driven more by national pride than actual military advantages.

Kunertova also mentions that hypersonic weapons are not necessarily a “game-changer” because there are no effective defenses against conventional ballistic missiles, let alone hypersonic weapons which promise to evade the same unreliable defenses. She also says that hypersonic weapons’ tradeoffs between speed, range and accuracy require further research to understand fully these new weapons’ effects. 

Furthermore, China and Russia may use hypersonics to circumvent existing arms control treaties. An article by the Union of Concerned Scientists notes that the New Strategic Arms Control Treaty (New START) does not explicitly restrict hypersonic weapons.

The source notes that New START was crafted with existing ballistic missile systems in mind and could be easily circumvented by putting nuclear warheads on new delivery systems such as HGVs or some other new rocket technology. Despite these doubts and counter-arguments against hypersonics, the US is not taking a zero-sum view of these weapons due to their potential threat to strategic security and stability. 

The US 2019 Missile Defense Review notes the advantage that space-based sensors’ sizeable viewable area has in tracking and destroying hypersonic weapons. Space-based sensors can detect and track missile launches from any part of the globe, do not require complicated legal procedures for basing rights and could also be armed with interceptors to increase the chances of a successful intercept.