Complex sentence: The Multi-Application Survivable Tether (MAST) experiment is an investigation designed to use picosatellite spacecraft connected by tethers to better understand the survivability of tethers in outer space.
Split into simpler sentences: The Multi-Application Survivable Tether (MAST) experiment is a picosatellite-based investigation of spacecraft connected by tethers. It will aid understading the survivability of tethers in outer space.