In all uses, please courtesy "Video courtesy of Analytical Graphics, Inc. (www.agi.com)."
Satellite collision with a statistical breakup model
This one-minute video demonstrates the approach trajectories of the two satellites prior to
impact, as well as a statistical breakup model with an example of propagated debris.
The breakup model is a statistical model that generates 1,000 debris samples for each satellite, numerically integrated in a full force model in STK/Astrogator. Statistical debris models employ stochastic processes useful for rapidly characterizing a debris event to understand where debris could go and can assist in risk analysis. While not requiring observation data to run, this model can be refined by seeding the statistical values with data from tracked debris as it becomes available. An output of the model is a high-precision catalog of ephemeris data. The breakup model used a Gaussian distribution of samples with a 1 km/s delta-V magnitude (sigma 1 km/s) and uniform density and mass distributions. The breakup model delta-V directions were set to Azimuth -90 deg and an elevation of 38 deg and -38 deg (sigma 30 deg). The propagator used a JGM2 gravity field with degree 12 and order 12. The computational time to generate these models in STK is extremely rapid with the ability to calculate results for several day propagations in less than 15 minutes on a single legacy processor. Since each piece is modeled individually, parallel processing techniques would provide near instant data if required. Values for propagators and breakup statistics are user controlled.
Satellite collision with an Evolve-based, statistical break-up model
This 1-minute video demonstrates the approach trajectories of the two satellites prior to
impact, as well as a statistical break-up model with an example of propagated debris.
This is a 1000 object statistical sample of more than 2,600 fragments predicted using a modification of the NASA Evolve debris model. This model abstracts structural and material fragmentation physics. Outcomes depend on the degree of contact between the two satellites, distinguishing between portions totally involved and those outside the contact area. This depiction uses initial on-orbit masses of 685 Kg for Iridium and 900 kg for Cosmos 2251 and assumes 30% direct contact for each object. The model can also release instantaneously energy stored in unexpended propellants, although that capability was not used in this case.
In all uses, please courtesy "Video courtesy of Analytical Graphics, Inc. (www.agi.com)."
AGI Viewer is free application
that allows you to experience STK-generated content in a dynamic and interactive 3D environment.
VDFs, the AGI Viewer file format, allows you to view the collision from the position and time of
your choosing. Plus, you can cycle through a series of stored views and camera paths that the STK
scenario author used to communicate the details of the event.
In all uses, please courtesy "Video courtesy of Analytical Graphics, Inc. (www.agi.com)."
Both STK and AGI Viewer provides users with the opportunity to incorporate 3D models of objects
into an accurate virtual globe environment. The following 3D models are in an MDL format to be
used with STK and AGI Viewer.
In all uses, please courtesy "Video courtesy of Analytical Graphics, Inc. (www.agi.com)."
Download the high-resolution graphics by clicking on the images below.
About SOCRATES
Since May of 2004, CSSI has been providing free online conjunction advisory services--SOCRATES--to
the satellite community, using AGI tools, to help the space community develop a better understanding
of the magnitude of the problem with satellite close approaches in Earth orbit. Since February 2008,
CSSI has worked closely with geostationary satellite operators to find ways to improve the accuracy
of the data used for these analyses in an effort to reduce the number of false alarms and thereby
reduce the risk of a potential collision. For more information, visit
http://celestrak.com/SOCRATES/.
About Iridium 33
More information is available for Iridium 33 at Spacecraft Digest.
About Cosmos 2251
More information is available for Cosmos 2251 at Spacecraft Digest.