This project investigates new methods for tracking space debris in the low-Earth orbit environment using optical and laser data.
The low-Earth orbit (LEO) environment (below 2000 km altitude) is cluttered with objects resulting from over 50 years of space operations. Providing reliable orbit predictions of these objects is very important, particularly in conjunction with assessments to protect satellite assets from being destroyed in a collision. When there is an abundance of tracking data available, the process of providing a good orbit prediction is relatively straightforward. A difficulty arises when there is only a limited amount of tracking data available since the procedures used to “best-fit“ the data are weakly-constrained.
The Space Debris Tracking System (STDS) at EOS Space Systems Pty. Ltd. (EOSSS) is located on top of Mount Stromlo, Canberra. The system tracks orbital objects using optical and laser techniques. The debris laser ranging (DLR) system currently requires an initial orbital track to be provided from the optical tracking system to track debris objects. This means the system is limited to approximately 4 hours of operation per 24 hours since the debris object has to be sunlit. This means tracking efficiency is critical.
Previous investigations have considered orbit determination and prediction from sparse tracking data in the case where 2 full passes of tracking data are available. Generally, a full pass of optical or laser data is around 1 – 4 minutes in duration. The accuracy requirement was set at 20 arc-seconds of angular error after a prediction period of 24 hours for the application of next-generation technology for remote ground-based laser manoeuvre of space debris objects. This application is considered a potential method to help alleviate the space debris hazard in the LEO environment but still needs to overcome some technology challenges before operation is possible.
This project will determine if full passes are necessary to still meet the accuracy requirements. This has important consequences in a tracking station network. If full passes are not required, then the tracking system can be tasked to track more objects in the operation window since the time spent on each object is reduced. This will lead to improved tracking efficiency which can be applied to a single station operation or a network of stations.
Data generated from existing tracking campaigns by EOSSS’ Mount Stromlo site will be used to assess the performance of the predictions by picking a subset of tracking data for the orbit determination and prediction process and comparing the resulting orbit prediction to subsequent observations.
The study will be focused on the altitude range 700-900 km since: (1) it is the densest populated region of the LEO environment and has been shown to be the most unstable in terms of a collisional cascading phenomenon; and, (2) is a realistic range for future (potential) ground-based laser manoeuvre campaigns.
The main outcomes expected are:
- A detailed assessment of orbital prediction accuracy over the densest altitudinal range 700-900 km;
- A reduction in the amount of redundancy in data collection so system tasking can be optimised;
- A benchmark data requirement for future integration with an optical and laser tracking network;
- An integral analysis to help enable next-generation debris hazard mitigation scenarios;
- A journal publication reporting on the results achieved.
The implications of the accuracy achieved will be considered within current operational systems.
This research is part of an ongoing long term collaborative effort between the SPACE Research Centre, RMIT University, and EOS Space Systems Pty Ltd. It is funded by Enterprise Connect and EOS Space Systems Pty Ltd though the Researchers in Business Grant scheme.