SDA National Defense Space Architecture

The author of this opinion piece knows whereof she speaks, having been former staff director of the House Armed Services strategic forces subcommittee. She knows many of the lawmakers, the services’ experts and the issues in detail. read on! The Editor.

As Congress considers the Pentagon’s $1.2 billion request for military space systems in Low Earth Orbit (LEO) and its other broader space portfolio, it would do well to consider the key factor of resilience at each decision point.

Building resilience into new defense space systems will remain challenging especially in a budget-constrained environment. It will require tough choices not just programmatically, but architecturally. The Defense Department would do well to justify their investment as not only for one orbital regime, but for the broader context of mission assurance.

President Biden’s FY 2022 budget is out, and for policymakers and practitioners in the space community one aspect in particular is getting attention: a $1.2 billion request for various military space systems in low-Earth orbit (LEO). This includes investments by organizations reporting into the Office of the Secretary of Defense (OSD), like the Space Development Agency, the Missile Defense Agency, and DARPA, all of which are investing in innovative space architectures and applications leveraging hardware commoditization and Software as a Service solutions. This marks a warranted and welcome trend toward innovation for these agencies – each of which should transition their reporting from OSD to the Space Force – but the question remains: why this investment in LEO architecture alone?

For the programs under the various OSD organizations, one concept appears again and again: resilience.

In the context of space architectures, the Defense Department defines resilience as:
The ability of an architecture to support the functions necessary for mission success with higher probability, shorter periods of reduced capability, and across a wider range of scenarios, conditions, and threats, in spite of hostile action or adverse conditions.

That’s a long way to say “Resilience means getting the job done even when the enemy is trying to mess you up.” It’s a noble cause, but is investment in only one orbital regime the optimal way to ensure a resilient architecture? Probably not. So how else can we build resilience into innovative space architectures?

CSIS graphic

Low-, Medium- and Geosynchronous Earth Orbits (CSIS graphic)

Look Up There is no doubt that launch and operating costs at LEO offers tremendous advantages to the emerging space industrial base, but operating at higher orbital regimes has advantages as well. Operating at Geosynchronous Equatorial Orbit (GEO) allows for more persistent staring sensors that could be used for queueing other sensors (that may be in LEO) or providing change detection capabilities. These architectural tradeoffs are not binary propositions. A constellation with satellites operating in both LEO and GEO provides the opportunity to disaggregate strategic and tactical missions, which can also reduce the risk of strategic miscalculation – which also supports resilience.

Look Down

Ensuring resilience for space-based capabilities is not limited to satellites. The capabilities themselves should be routable through non-space platforms like aerostats, UASs, other aircraft, even terrestrial pseudolites, and sea-based platforms.

Even with the establishment of Space Force, space-based capabilities are primarily supporting terrestrial operations. Looking to the other recognized warfighting domains to redundant capabilities and interoperability will enhance architectural resilience. This concept will become increasingly important in the context of joint all domain command and control, where sensors and effectors will be paired across all warfighting domains (land, air, sea, space, and cyber).

Look All Around

One of the technology areas where DoD has wisely chosen to invest in the context of LEO architectures is optical intersatellite laser links (OISLs). These links increase the bandwidth capacity and decrease the latency of data, getting more data faster to those who need it. For tactical users of space-derived data, this is key. While most programs are currently working on bringing this capability to LEO architectures, OISLs could also be used for transmitting data between different orbital regimes, bringing those same benefits to a hybrid architecture.

In general, investing in technologies that connect the satellites, process the data onboard, route the data across the network, and manage the constellation autonomously all help build resilience into space architectures.

Resilience is a key attribute of any defense space architecture – legacy or disruptive. It is prudent from a mission planning perspective – and absolutely necessary given the emergence of threats against our military space systems. But resilience is infamously difficult to define, measure, and engineer into a space system. Investment in a single orbital regime may be necessary but not sufficient to ensure that our space systems are able to perform their mission through a contested space domain.

The Defense Department surely understands this, and as they continue to request funds in a budget-constrained environment, they would do well to justify their investment as not only for one orbital regime, but in the broader context of mission assurance.

Sarah Mineiro is an adjunct senior fellow at the Center for a New American Security and former staff director of the House Armed Services strategic forces subcommittee.