Frequently Asked Questions
SDA contributes to the defense of our nation by designing and rapidly deploying the National Defense Space Architecture, a threat-driven constellation of small satellites that deliver critical services to our warfighters from space. Services include low-latency data transport integrated with tactical data links, tracking of advanced missile threats, custody of time-critical land and maritime targets, and space-based battle management, to name a few.
Latin for “always faster”. SDA recognizes that good enough capabilities in the hands of the joint warfighter sooner may be better than delivering the perfect solution too late. Because of this, it means we as an agency accept a higher level of risk, employ novel business models, and move to develop and field capabilities more quickly than you might see in “traditional” government agencies. We believe this builds resiliency into our people and our product—the National Defense Space Architecture.
When we say “semper citius”, we mean that we are moving at or ahead of the speed of the threat because we know the joint warfighter is counting on us.
pLEO stands for proliferated low Earth orbit. This means a constellation of many (hundreds or thousands, potentially) satellites orbiting at altitudes of less than 2000 km. Many current space-based military systems are orbiting further from the earth in orbits called medium Earth orbit (MEO) or geosynchronous Earth orbit (GEO).
A proliferated architecture of small satellites allows for resilience by providing capabilities that are not compromised by disruption or defeat of a small number of assets. By employing such design principles as mesh networks, the National Defense Space Architecture (NDSA) is built to continue functioning in the event that individual nodes become unavailable. The satellites that comprise the NDSA are also smaller, cheaper, and quicker to deliver and replace than some of our exquisite defense space assets deployed in limited quantities.
SDA’s model relies on proliferation as a key tenet. And our initial architecture will be primarily in low Earth orbit.
Low Earth orbit offers a number of benefits when compared to orbits of higher altitude, including less expensive orbit insertion, better viewing geometries for space-based earth observation, and lower latencies and power requirements for communications transmissions to terrestrial systems. For these reasons, there has also been an emergence of technology providers in the commercial sector seeking to deliver communications capabilities through satellite constellations in LEO. These are some of the reason why SDA will initially proliferate capabilities in LEO.
A “layer” in SDA’s National Defense Space Architecture is a particular function of the architecture that delivers or enables a warfighting capability. For instance, the Transport Layer will provide a mesh network comprised of communication satellites that connect to one another and to other space vehicles and ground stations via optical intersatellite links (OISLs). The Tracking Layer and Custody Layer provide sensing functions for advanced missile threats and time-critical land and maritime targets, and connect to the Transport Layer to provide threat indications and targeting data to our warfighters in real time.
Not every layer will have a dedicated constellation of satellites. Some layers will deliver capabilities with sensors, processors or other technologies hosted on another layer’s satellites. For instance, the Battle Management Layer will provide a software framework and processing capabilities that will be hosted on most or all of the NDSA satellites
A tranche is essentially one generation, or iteration, of SDA’s National Defense Space Architecture.
Tranche 0 (FY22) – Warfighter immersion: The minimum viable product is demonstrating the feasibility of the proliferated architecture in cost, schedule, and scalability towards necessary performance for beyond line of sight targeting and advanced missile detection and tracking.
Tranche 1 (FY24) – Initial warfighting capability: Regional persistence for tactical data links, advanced missile detection, and beyond line of sight targeting.
Tranche 2 (FY26) - Global persistence for all in Tranche 1. This will incorporate lessons learned from operating gen 0 for at least two years.
Tranche 3 (FY28) – Advanced improvements over Tranche 2. This includes better sensitivity for missile tracking, better targeting capabilities for BLOS, additional PNT capabilities, advances in blue/green lasercom and protected RF comm.
Tranche 4 (FY30) – Continual advances to the layers, including additional capabilities identified as current or future threats to the warfighter.
Spiral development is the process of incrementally delivering new capabilities. SDA is committed to delivering new defense space capabilities in two-year tranches – with each tranche improving upon the last – and informing the development of those capabilities with the latest available technology advancements and intelligence assessments. Spiraling also enables SDA plans and architecture designs to quickly pivot in response or even preemptively to advances in the threat.
These are all mechanisms federal agencies use to solicit input from potential product, capability, and service providers. Some of them, like a Request for Information (RFI), seek industry feedback and do not result in a contract award. Others, like a Broad Agency Announcement (BAA) or Request for Proposals (RFP), are looking for prospective performers to submit various types of proposals to an evaluation process likely resulting in some number of contracts awarded.
SDA is often limited in their capacity to answer specific questions following the publication of solicitations so as not to provide an unfair advantage to one bidder over another.
SDA is an independent defense agency under the Office of the Under Secretary of Defense for Research & Engineering (OUSD(R&E)). This independence is critical for SDA to be the Department’s constructive disruptor for space, until the agency has time to innovate, flourish, and deliver.
SDA’s focus is on delivering the National Defense Space Architecture (NDSA) on a two-year spiral development model beginning with our inaugural tranche in fiscal year 2022.
DARPA and the Space Rapid Capabilities Office work to develop leap-ahead technologies that might enable the capabilities brought to the warfighter through the NDSA. SDA works in partnership with these organizations to potentially transition their technologies into further development and fielding.
The Space and Missile Systems Center (SMC) works to deliver many of the space-based systems on which the joint warfighter relies today. SDA is working closely with SMC to ensure the NDSA complements those systems and shares common resources, such as ground architecture and launch services, where feasible.
SDA was stood up with the understanding that it would eventually be part of the U.S. Space Force, should Congress act to create that 6th branch of the military services. While details are still being worked out within the Department, SDA does plan to transition to the U.S. Space Force, likely around the start of fiscal year 2023 (October 2022).
SDA will practice responsible space traffic management to both orbit and deorbit safely and securely as required by national standards and international norms.
No. SDA strictly adheres to Department of Defense policy regarding Earth imaging that protects the privacy of U.S. citizens.