Thirty years after the European Space Agency first demonstrated the power of flying two satellites in very close formation, the concept was recently recreated. By temporarily positioning two Copernicus Sentinel-1 radar satellites to replicate the pioneering ERS-1–ERS-2 ‘tandem mission’, ESA achieved one-day repeat radar imaging of the same Antarctic region.

The results once again demonstrate how this approach can be used to measure glacier motion and pinpoint the critical grounding line with exceptional precision.