Daniel L. Oltrogge, COMSPOC; Salvatore Alfano, COMSPOC; Robert Hall, COMSPOC
Keywords: Russian ASAT Test, operator workload, automated collision avoidance maneuver
Abstract:
This paper performs a follow-up analysis of the Russian ASAT intercept test conducted November 15, 2021, launching an ASAT weapon system to intercept and destroy the on-orbit COMOS 1408, a defunct Soviet Electronic Intelligence (ELINT) satellite that was launched in 1982. In our original paper, we utilized published NOTAMs and public orbit and spacecraft data to infer the likely ASAT engagement scenario employed, and that scenario was then used to predict where generated COSMOS 1408 debris fragments were likely to go, what satellites would be affected, and how operator workloads would be changed because of the test. We had predicted that increases in close approach and collision warnings, accompanied by increases in avoidance maneuvers required for flight safety, would place a burden on certain operators of Sun-synchronous orbiting spacecraft (largely used for Earth observing/imaging missions) for approximately 1.5 years after the intercept occurred.
A special focus of this research is placed on assessing how debris from a fragmentation event adversely impacts spacecraft operators, their SSA knowledge, their ability to detect and mitigate high collision threat events, and their use of maneuvering fuel within a large constellation framework. This paper compares these original predictions of encounter rates, collision risk to Low Earth Orbit (LEO) spacecraft (especially spacecraft in sun-synchronous orbits), and orbit lifetime estimates with actual conjunctions and orbit lifetimes detected by operational flight safety systems and services. Comparisons of actual fragmentation debris tracking with debris volume evolution in a continuum model and discrete breakup modeling to create a representative debris field are performed.
We will update our initial assessment of metrics used for the comparison of the Russian ASAT test with other notable fragmentation events, to include the Chinese ASAT test of 2007, USA 193 Shootdown event, India ASAT, and Iridium/COSMOS collision). We compare the dates, altitudes, relative velocities, and debris quantities and lifetimes. We also assess, based upon the estimated relative velocities, whether the event can be considered to be a hypervelocity collision (which is spacecraft material dependent, with, for example, steel ranging from 3.1 and 6 km/s and aluminum from 3.8 to 6.5 km/s). We evaluate the energy per unit mass associated with the event to determine if the collision can be considered as a catastrophic collision (with greater than 40 Joules per gram being considered as a rough guide) and show that all events can be seen to be catastrophic as they greatly exceed this criterion. And we compare the number of fragments tracked by the Space Surveillance Network at some point, with those still on orbit as of the AMOS conference, versus predictions from our breakup model predictions. An 80th percentile orbit lifetime estimate is made for each debris fragmentation event, and estimated orbit lifetimes for all breakup model fragments are summed as a proxy for the overall degradation of the space environment.
We will also update to our characterizations of operator collision risk as a function of altitude which identifies as much as 20% reductions in flight safety and sustainability stemming from the Russian ASAT test at certain altitudes, and a doubling of collision risk for certain orbit conditions.
Date of Conference: September 27-20, 2022
Track: Space Debris