Good question – the answer is not simple. First, neither system exists operationally though ADR systems are getting very close. The first criteria for use would be if a system (i.e., ADR vs JCA) actually exists to use. When there is only one, the debate is purely academic.
After that clearly, ADR permanently eliminates the collision risk while JCA only temporarily reduces the orbital collision risk. However, JCA will most likely be much less expensive than ADR but the JCA cost will have to fold in the potential "false alarm" problem (i.e., one might "nudge" an object when in reality the two objects would have missed so the true cost for remediation might be a multiple [2 or 3?] of the cost of a JCA mission). However, for the very large objects over 1,000 kg (especially 9,000 kg SL-16 RBs), removing their collision risk does not eliminate risk; it just moves the risk to aviation and ground impacts while JCA does not deflect the risk to another domain.
Next, ADR remediates statistical risk of collision (i.e., long-term over many years and many close approaches) while JCA remediates a deterministic collision risk (i.e., reduce the risk from a single encounter). These are both very different in magnitude and uncertainty plus potentially apply different legal and regulatory perspectives. For example, you would never have ADR operate on an operational satellite, however, JCA might be a viable means for an operator of a satellite that did not have collision avoidance capability. This makes JCA, in essence, a space traffic management (STM) action and, possibly even, a constellation resiliency activity.
Dr. Darren McKnight
Technical Director, Centauri
darren.mcknight@centauricorp.com
15020 Conference Center Drive
Chantilly, VA 20151
Phone: 703-674-3137
Mobile: 703-402-4484
www.centauricorp.com
"Since all models are wrong, the scientist cannot obtain a 'correct' one by 'excessive elaboration' and the scientist must be alert to what is importantly wrong. It is inappropriate to be concerned about mice when there are tigers abroad."
George Box, "Science and Statistics," Journal of the American Statistical Association, 1976