Over the last two budget cycles, the Department of Defense (DoD) and Congress have played institutional ping pong over which agency should develop the Hypersonic and Ballistic Tracking Space Sensor (HBTSS). Despite widespread and bipartisan support for fielding a space-based system of missile tracking sensors, this wrangling has created unnecessary uncertainty and difficulty for its development. Given the emergence of hypersonic missiles and the continued proliferation of more complex and maneuvering ballistic missiles, space-based sensors will be critical to evolving missile defense architectures. Perpetuating this institutional uncertainty threatens to seriously impair the prospect of realizing the widely shared vision of fielding space sensors at the speed of relevance.
In its last two budget submissions, the Trump administration has proposed transferring research, development, test and evaluation (RDT&E) funds to develop HBTSS from the Missile Defense Agency (MDA) to the new Space Development Agency (SDA). Each time, Congress has voiced its opposition throughout the authorization and appropriations processes, transferring policy authority and funds back to MDA to develop and deploy the HBTSS sensor payload. In their markup of the FY 2021 authorization and appropriations bills, all four major defense committees again provided funding for MDA to pursue HBTSS rather than SDA. The repeated decision to reject congressional oversight on HBTSS development increases institutional uncertainty at a time when stable funding and program management is critical.
The Need for Space Sensors
HBTSS should be a priority investment for the Defense Department because it enhances the effectiveness of almost any missile defense system. Unlike surface-based sensors, space-based sensor systems have a wider field of vision, unencumbered by the horizon. This wider field of vision allows space-based sensors to track missiles continuously from launch to intercept, rather than having to pass that data between terrestrial sensors when the missile leaves their field of vision. With effective orbit planning, space sensors can provide a persistent capability to detect and track ballistic and hypersonic missiles.
The ability to continuously track the entirety of a missile’s flight is an essential capability for modern missile defense architectures. In ballistic missile defense, continuous tracking allows defenders to see the deployment of countermeasures and formation of debris around the warhead, making the critical task of discrimination easier. Effective discrimination allows defenders to target interceptors only at the lethal warhead instead of countermeasures or debris travelling alongside it.
HBTSS will also be critical to countering new hypersonic missile threats. Hypersonic glide vehicles skim along the atmosphere, enabling them to maneuver more widely than ballistic missiles that travel through space. This maneuverability places a premium on wide-area sensor coverage to reduce the need to pass data between multiple platforms to maintain a single track of the threat. The wide-area coverage provided by space-based sensors will thus be critical to any future hypersonic missile defense architecture.
Institutional Ping Pong
Instead of buckling down on the development of this important capability, DoD and Congress have engaged in a game of budgetary and institutional ping pong over which agency should be responsible for developing HBTSS. Each of the last two budget cycles has played out roughly the same. Each time, DoD submits its budget with RDT&E funding for HBTSS as part of the Space Development Agency. In response, each congressional defense committee would voice its disapproval and transfer that funding back from SDA to MDA.
The 2020 National Defense Authorization Act (NDAA) seemed to settle the matter by including a mandate that the Secretary of Defense assign primary responsibility for development of the HBTSS sensor payload to MDA. Nevertheless, the FY 2021 DoD budget included no HBTSS funding for MDA. To meet the requirements of the law, MDA director Vice Admiral Jon Hill testified in March that MDA planned to retain its responsibility for the HBTSS sensor payload in 2021, but would use SDA funding to execute its efforts. While this arrangement effectively consolidates funding for space programs under SDA, it reduces transparency in the program, undermining a clear understanding of its priority and organizational leadership. Each of the four major defense committees has rejected this approach, transferring funds from SDA to MDA to develop and deploy HBTSS.
This back and forth over funding and execution of HBTSS prevents prioritization of the program by either agency. SDA is unlikely to prioritize a program that it is funding but not executing, and MDA will have a hard time prioritizing a program that it is responsible for but has no agency funding. The lack of institutional ownership of HBTSS threatens consistency in the development of funding plans in the Future Years Defense Program (FYDP) and its eventual transition from RDT&E to procurement.
A Complementary Path Forward
While there is some logic to consolidating space programs under SDA and eventually the new Space Force, it is clear that congressional oversight will prevent that consolidation in the case of HBTSS. There are strong reasons for DoD to acquiesce to Congress and submit its funding request for HBTSS in the MDA budget. MDA development of the sensor payload will ensure that program requirements will be optimized for ballistic and hypersonic missile tracking. The missile defense-centric mission of MDA could also ensure that those requirements are effectively prioritized. The addition of more general requirements for a large set of missions has contributed to substantial cost growth in previous satellite constellations. SDA’s broader mission to provide space capabilities could enable this sort of requirements growth, whereas MDA’s missile defense-centric mission could help contain it.
Instead of resisting the repeated bipartisan wishes of Congress and delaying the development of HBTSS, DoD should accept the payload development within MDA as part of a two-tracked complementary path forward. During the last two years, MDA and SDA have already had to develop a cooperative working relationship on the program. This cooperation on HBTSS could allow MDA to leverage SDA investments in the infrastructure of future space architectures like reducing launch costs and information transport layers. Allowing SDA to prioritize those investments could create greater cost savings for all manner of future space systems, allowing it to support the Space Force and joint missions more effectively.
CSIS does not take specific policy positions; accordingly, all views expressed above should be understood to be solely those of the author.
(Photo Credit: DARPA)