Session
Technical Session XI: Around the Corner
Abstract
Recent events, such as the February 2009 Iridium 33-Cosmos 2251 collision, have brought attention to the changing nature of the Low Earth Orbit (LEO) environment. The population of objects recorded by the US Space Catalog has doubled since 1992, resulting in an increased risk of on-orbit collisions. USSTRATCOM’s Space Surveillance Network (SSN) tracks resident space objects (RSO) and publicly releases a subset of these data to support conjunction (collision probability) analyses. However, these early warning systems did not prevent the Iridium – Cosmos collision. Conversely, there have been a number of high profile ISS false alarms where the crew has unnecessarily interrupted operations to take shelter. These examples highlight the need for better Space Situational Awareness (SSA) in LEO. The Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) mission will improve SSA using a low-cost small satellite constellation. An operational STARE constellation of 18 nanosatellites will be able to assess greater than 99% of all conjunctions involving objects larger than 10 cm and has the capability to reduce the current collision false alarm rate by two orders of magnitude up to 24 hours ahead of closest approach, in effect reducing the number of actionable alerts to one per satellite lifetime. This is a significant improvement over today’s capability, which provides so many false alarms (estimated at one per month per satellite for a LEO sun-synchronous orbit) that alerts are regularly ignored due to the inability of the space assets to move frequently.
Presentation Slides
The Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) mission
Recent events, such as the February 2009 Iridium 33-Cosmos 2251 collision, have brought attention to the changing nature of the Low Earth Orbit (LEO) environment. The population of objects recorded by the US Space Catalog has doubled since 1992, resulting in an increased risk of on-orbit collisions. USSTRATCOM’s Space Surveillance Network (SSN) tracks resident space objects (RSO) and publicly releases a subset of these data to support conjunction (collision probability) analyses. However, these early warning systems did not prevent the Iridium – Cosmos collision. Conversely, there have been a number of high profile ISS false alarms where the crew has unnecessarily interrupted operations to take shelter. These examples highlight the need for better Space Situational Awareness (SSA) in LEO. The Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) mission will improve SSA using a low-cost small satellite constellation. An operational STARE constellation of 18 nanosatellites will be able to assess greater than 99% of all conjunctions involving objects larger than 10 cm and has the capability to reduce the current collision false alarm rate by two orders of magnitude up to 24 hours ahead of closest approach, in effect reducing the number of actionable alerts to one per satellite lifetime. This is a significant improvement over today’s capability, which provides so many false alarms (estimated at one per month per satellite for a LEO sun-synchronous orbit) that alerts are regularly ignored due to the inability of the space assets to move frequently.
