Historical Collisions in Low Earth Orbit
- Paper number
IAC-06-B6.2.05
- Author
Dr. Paula H. Krisko, ESCG/Jacobs Sverdrup, United States
- Year
2006
- Abstract
Collisions between objects in orbit have been known to occur for many years. The available evidence includes returned surfaces which have recorded impacts by sub-millimeter sized objects (i.e., orbital debris and meteoroids), and more recent unexplained debris generating events that hint at possible impacts of resident space objects (RSO’s) with objects on the order of one centimeter in size. The NASA Orbital Debris Program Office is engaged in a study to formulate the low-Earth orbit (LEO) environment in terms of past and current-day collisional activity between objects larger than one centimeter in size. One prong in the study is a modeling effort involving the debris environment evolution models LEGEND and EVOLVE. These models were developed at NASA/JSC for the purpose of providing insight into the long-term effects (over 100 years) of controlled/uncontrolled fragmentation in Earth orbit. They find additional application in the current study. Preliminary results suggest a small but nontrivial collision rate, on the order of tens of events, over the last 35 years in LEO. This rate is dominated by events involving breakup fragments and large RSO’s, though a sizeable minority of the events (i.e., around 30%) involve RORSAT sodium-potassium droplets and RSO’s. The sodium-potassium droplets/RSO rate appears to decrease over time as atmospheric decay takes those droplets out of the LEO high-traffic regions. The modeled increasing rate of breakup fragment/RSO events is expected given the continuing addition of small fragment sources to the environment.
Verification of this historical collision activity is difficult in radar tracking data since the small impactors generally result only in cratering of the large RSO’s (i.e., non-catastrophic collisions). Still the activity may be notable in small unexplained changes in RSO ephemeris.
- Abstract document
- Manuscript document
IAC-06-B6.2.05.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.