PTD 1 (Hydros-C)

PTD 1 [Tyvak]

The PTD 1 (Pathfinder Technology Demonstrator) is a 6U CubeSat technology demonstration mission that will test the operation of a variety of novel CubeSat subsystems in low-Earth orbit, providing significant enhancements to the performance of these small and effective spacecraft.

The primary goal of the first Pathfinder Technology Demonstrator spacecraft is to flight qualify and characterize a novel thruster provided by Tethers Unlimited, Inc., which uses electrolyzed water as fuel for a small thruster.

Each PTD mission consists of a 6-unit (6U) CubeSat weighing approximately 11 kilograms and measuring 30 cm × 25 cm × 10 cm. Each PTD spacecraft will also be equipped with deployable solar arrays that provide an average of 44 watts of power while in orbit.

The PTD-1 mission launched on 24 January 2021 to demonstrate the Hydros-C propulsion system with a water-based propellant that was developed through a public-private partnership with Tethers Unlimited, Inc., of Bothell, Washington. Carrying approximately one pint of water in a flexible bladder contained within in a metal vessel aboard the CubeSat, the propulsion system separates water into hydrogen and oxygen propellants by applying an electric current through the water. The propulsion system uses power provided by the spacecraft’s solar arrays to operate the miniature water electrolysis system. The demonstration tested propulsion performance through programmed thrust events which change spacecraft velocity and altitude executed by the hydrogen and oxygen-fueled combustion. This propulsion system provides higher thrust compared to other propulsion technologies while requiring lower power input.

The data collected during this flight demonstration will be incorporated in future Hydros-C and its larger Hydros-M systems. The Hydros-M system is planned for several missions including NASA Science Mission Directorate’s Polarimeter to UNify the Corona and Heliosphere (PUNCH) mission. PTD-1 is the first mission to demonstrate a water-based electrolysis propulsion system on any type of spacecraft.

It was selected in 2017 by NASA's CubeSat Launch Initiative (CSLI) to be launched as part of the ELaNa program.