The following additional comment by Campbell at the same event may shed some light as why this happened: Likewise, the US military has stated that they did not have any warning. It also appears that either Iridium or the JSpOC terminated the collision screening for the Iridium constellation at some point between July 2007 and the collision in February 2009, as Iridium has made repeated public statements that they did not receive any warning. This error is due to the inaccuracy of the publicly available TLEs used to perform the analysis. However, on the day that they collided, the Iridium-Cosmos conjunction wasn’t even listed in the Top 10 most dangerous conjunctions for that day: SOCRATES calculated it to have a miss distance of just under 600 meters. Low accuracy screening of the entire satellite catalog using just the publicly available TLEs is already available publicly from the SOCRATES service provided by the Center for Space Standards and Innovation. A large portion of blame can be laid at Iridium’s door for not exercising the same degree of caution and safety shown by other satellite owner-operators. This leads me to believe that Iridium was not getting the high accuracy screening. Clearly, if the JSpOC was screening the Iridium constellation daily for collisions using the same high precision methods used to protect the military and NASA satellites, then the quality of the data would have been good enough to make avoidance maneuver decisions, just like NASA, the military, and CNES. There is definitely something amiss here.
Even if we had a report of an impending direct collision, the error would be such that we might maneuver into a collision as well as move away from one. The other problem is that with the error bounds associated with those reports, we are not going to be sure what to do. Campbell questioned the error in those warning reports and their usefulness for avoidance maneuvers:
He also stated that the JSpOC was giving them daily warning of close approaches, with over 400 approaches within 5 kilometers being reported each week over the entire Iridium constellation.įurther comments as to what Iridium was doing about these close approaches given at the same forum are distressing. At a forum organized by the George Marshall Institute in June 2007, John Campbell, the Iridium vice president for governmental affairs, stated that the debris field from the Chinese anti-satellite test had increased the number of “serious conjunctions” on the Iridium constellation by 15%. Clearly, Iridium cannot claim that they were unaware of the collision risk to their satellites. Instead, there is plenty of blame to go around for all involved.Ī large portion of blame can be laid at Iridium’s door for not exercising the same degree of caution and safety shown by other satellite owner-operators.
As is usually the case, there is no single “bad guy” that we can all hang in effigy over this satellite collision. There is a cacophony of voices from all fronts demanding to know who is to blame for this preventable incident. << page 1: it’s all about the data Sins of omission and commission The Iridium 33/Cosmos 2251 has added to the orbital debris environment in low Earth orbit how could it happened? (credit: AGI)