Space Situational Awareness (SSA)

SSA is the ability to characterize activities in space and the space environment (including space weather). Space Surveillance and Tracking (SST) is a subset of SSA focused on the motion and activities of objects, both active and inactive, in orbit.

Space Surveillance and Tracking

To understand the motion of objects, SST requires observations and measurements of the positional information of objects in orbit, with subsequent processing to recover orbits and trajectories of these objects.

In addition to the motion, the characteristics of an object, for example its tumbling motion, is an important part of SST.

Space situational awareness graphic 1 Toby Harris Unity 15 October 2021
Space situational awareness graphic 1 with planet Toby Harris Unity 15 October 2021

Space Situational Awareness

SSA encompasses a wide range of activities, from observing multiple objects using long-range remote sensing such as radar or telescopes, down to close proximity observations of a specific target, known commonly as inspection.

For general space missions, SSA is essential to ensure safe and successful mission operations, and prevent potential catastrophic collision events between space objects.

SSA and our current and future missions

To meet our mission goals:

Our missions are complex Rendezvous and Proximity Operation (RPO) missions. They can involve multiple maneuvers between different orbits, maneuvering in close proximity to client objects, and docking with objects to provide a variety of services. To ensure safe, successful missions, it is essential to have a good understanding of how these objects are moving and their relation to other objects in the orbital environment.

To support SSA capabilities:

Astroscale’s spacecraft and missions are highly flexible, with payloads capable of providing sensor data that can be used to underpin SSA capabilities. As our technologies develop, we aim to use our spacecraft’s capabilities to support a broader ecosystem of SSA data services.​

Building on SSA learning from ELSA-d

To better understand our future mission needs from SSA we are leveraging ELSA-d as much as possible, working alongside SSA service providers and exchanging data to consider how those capabilities can be used for RPO missions.


We’re developing new on-orbit sensing capabilities, demonstrated by the upcoming ADRAS-J inspection mission.


The COSMIC mission also considers in-orbit refurbishment, such as examining in-situ SSA.

All Services