Navigation system
Delta-DOR
A precise angular-position technique: two widely separated stations record the spacecraft's signal and that of a distant quasar, and the tiny difference in arrival times pins down the spacecraft's position on the sky to a few nanoradians — vital for accurate planetary arrivals.
Related
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
- NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.
- ESAEuropean Space Agency
European missions, observatories, and space science imagery.