Drift Recovery and Station Keeping Results for the Historic CanX-4/CanX-5 Formation Flying Mission
Bibliographic record
Abstract
Specialized drift recovery and station keeping algorithms were developed for the Canadian Advanced Nanospace eXperiments 4 and 5 (CanX-4 & CanX-5) formation flying mission (launched 30 June 2014), and successfully verified on orbit. These algorithms performed almost exactly according to predictions. The highly successful CanX-4 and CanX-5 formation flying demonstration mission was completed in November 2014, ahead of schedule. CanX-4 & CanX-5 are a pair of identical formation flying nanosatellites that demonstrated autonomous sub-metre formation control, with relative position knowledge of better than 10 cm and control accuracy of less than one metre at ranges of 1000 to 50 metres. This level of performance has never before been seen on nanosatellite class spacecraft to the author’s knowledge. This capability is crucial to the future use of coordinated small satellites in applications such as sparse aperture sensing, interferometry, ground moving target indication, on-orbit servicing or inspection of other spacecraft, and gravitational and magnetic field science. Groups of small, relatively simple spacecraft can also replace a single large and complex one, reducing risk through distribution of smaller instruments, and saving money by leveraging non-recurring engineering costs. To facilitate the autonomous formation flight mission, it was a necessary precondition that the two spacecraft be initially brought within a few kilometres of one another, with a low relative velocity. Complicating this was the fact that the CanX-4 and CanX-5 spacecraft were released separately from their shared launch vehicle, drifting thousands of kilometres apart in the short time it took to fully commission one spacecraft. Therefore, a system to calculate fuel-efficient recovery trajectories and produce the corresponding spacecraft commands was required, another first on the nanosatellite scale. This system was also extended to provide station keeping capabilities in the time between individual formation experiments, to keep the spacecraft safely separated without allowing their distance to grow large again.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".