Home / Space / DARPA Space-WATCH employing Commercial LEO Space Based Sensors (SBS) to enhance DOD Space Situational Awareness (SSA)

DARPA Space-WATCH employing Commercial LEO Space Based Sensors (SBS) to enhance DOD Space Situational Awareness (SSA)

Space has become increasingly militarized, with several countries developing antisatellite weapons (ASAT) and microsatellites capable of causing damage to other satellites. Additionally, the deployment of space robots for satellite repairs and comprehensive space awareness has become a priority. As a result, countries are taking measures to protect their space assets by establishing space commands and forces. The U.S. Government, particularly the Department of Defense (DoD) and Department of Commerce (DoC), is making significant investments in Space Domain Awareness (SDA) to understand the space environment better. As the proliferated LEO (pLEO) commercial and defense ecosystems grow the need for understanding the environment is growing along with it.

The US Strategic Command defines SSA as “The requisite current and predictive knowledge of space events, threats, activities, conditions and space system (space, ground, link) status capabilities, constraints and employment — to current and future, friendly and hostile– to enable commanders, decision-makers, planners and operators to gain and maintain space superiority across the spectrum of conflict.”

SDA is crucial for ensuring safe satellite operations and responsible space stewardship, similar to how the Federal Aviation Administration (FAA) manages air traffic. Currently, the Space Surveillance Network (SSN) primarily relies on ground-based radars to sense and track space objects. To overcome the limitations of ground-based sensors and enhance capability and capacity, DARPA launched the Space-WATCH program in January 2023, aiming to transition observations from the ground to constellations of satellites in Low Earth Orbit (LEO).

For deeper understanding of Space Domain Awareness (SDA) please visit: Space Domain Awareness (SDA): Ground-Based Radars, Telescopes, and Space-Based Sensors for Countering Space-Based Threats

The primary objective of the Space-WATCH program is to provide real-time and persistent tracking of all objects in LEO. By leveraging the vast number of low-cost sensors on commercial and government satellites in LEO, Space-WATCH aims to enhance situational awareness and enable timely notifications of anomalous actions to ground-based operators.

This approach offers a cost-effective solution by capitalizing on existing sensor technology and creating a safer LEO environment for all participants. This will provide the opportunity for commercial LEO operators to capitalize on an additional revenue stream by providing on-orbit observations that will make the LEO environment safer for all participants.

Space-WATCH Program

Space-WATCH consists of three major components: two Technical Areas (TAs) and a Working Group (WG). TA1 focuses on wide-area tracking using commercially-hosted sensing and detection. Commercial LEO operators will sell data products generated by their sensors, which will be processed by TA2 for real-time automated data fusion and exploitation. The WG will develop a data-as-a-service marketplace to incentivize commercial operators to sell collected data to the government.

The Space-WATCH program emphasizes the establishment of an “as-a-service” model, encouraging data collection from non-government-owned sensors for a comprehensive operational picture of LEO. It involves collaborations with commercial performers to upgrade existing sensors or develop alternative sensors for enhanced data collection. By integrating various sensors and leveraging automation, Space-WATCH aims to minimize object uncertainty and provide timely information for decision-making.

Throughout the program, Space-WATCH will focus on key metrics such as object size resolution, coverage area, and data delivery time.

TA1 program metrics Space-WATCH are fundamentally concerned with three things:
 What can you see and how well can you see it? A simple metric proxy here is minimum
object size, and what can be resolved, likely as a function of range.
 Where, when, and how often can you see it? Marries what you can see with orbitology
and proliferation expectations – this should define a potential area of regard, per satellite
and then per constellation.
 How quickly can you get that information to someone who can do something with it?
Based on your data processing and networking expectations on when the data product
can be provided.

Program Structure

The program is structured into three phases, including an initial six-month Phase 0 for architectural design and development of a dynamic pricing model.

Space-WATCH is a three-phase program (including Phase 0) spanning 34 months across two Technical Areas (TAs) and a Working Group (WG). TA1 and the WG each begin with a 6-month Phase 0 to produce an initial architectural design.

The Phase 0 portion of the SpaceWATCH program is a six-month period of performance to a) do an engineering study/reference architecture, and b) work with the Government team to better understand overall objectives for, and to develop, an initial dynamic pricing model for how to compensate commercial operators for sensor data sold to Space-WATCH.

Following Phase 0, there will be a 12-month Phase 1 for TA1 to implement the design from Phase 0. At the beginning of Phase 2 of the program (if not earlier), Space-WATCH enabled satellites will begin providing data, which will implement the data-as-a-service model for a 16-month pilot.
Continual launches of Space-WATCH enabled satellites are anticipated throughout the 16-
month Phase 2.

This is followed by a 12-month Phase 1 for the implementation of the design, and a 16-month Phase 2 pilot phase with continual launches of Space-WATCH enabled satellites.

Throughout the program, the Space-WATCH Government team will work with commercial
performers to design upgrades and/or modifications to their existing sensors (such as star
trackers collecting data on the light side of their orbit), and then develop alternative sensors
(such as long wave infrared (LWIR)) to serve as hosted payloads on commercial satellites that
can collect data on the dark side of the orbit.


The ultimate objective of Space-WATCH is to achieve comprehensive coverage and timely information of all objects in LEO. For the purposes of this program, these program metrics are defined as having less than a 30-minute revisit time coupled with less than 10 km position uncertainty.

By leveraging commercial LEO constellations and data-as-a-service models, the program aims to revolutionize space situational awareness, enhance space traffic management, and ensure the safety and security of space assets.

In conclusion, the DARPA Space-WATCH program represents a significant advancement in space situational awareness by harnessing the potential of commercial LEO space-based sensors. Through collaborative efforts and innovative approaches, the program aims to overcome the limitations of ground-based systems and provide real-time tracking and monitoring of objects in LEO. This initiative will contribute to the development of a safer and more sustainable space environment, benefiting both government and commercial space operators.











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