This is an image of Momentus' Ardor thruster for Ardoride, a multi-kilowatts propulsion system the firm is developing to power 500 to 1,000-kilogram spacecrafts. Momentus is testing the technology in its laboratory and plans to fly it for the first time in 2020. Credit: Momentus

SAN FRANCISCO — Mikhail Kokorich, the space industry investor who founded Russian small satellite builder Dauria Aerospace, is the founder and president of Momentus, a Silicon Valley startup focused on water plasma propulsion.

Momentus plans to demonstrate Vigor, its first water plasma thruster, by sending it into orbit in February 2019 on a 16-unit cubesat launched from a Russian Soyuz rocket. In 2020, Momentus plans a flight demonstration of the Ardor thruster it is developing for its Ardoride propulsion system to power 500 to 1,000-kilogram spacecraft. For now, Momentus’s Ardor technology is undergoing laboratory testing, Kokorich said by email.

“We are developing the first in-space rockets powered by water plasma engines,” Kokorich said. “We use solar energy to heat water with microwaves up to the sun’s surface temperature and eject the superheated gas through the nozzle to create thrust. One of the main problems we solved is how to make sure that plasma will not vaporize the chamber walls and nozzle.”

Momentus is participating in Y Combinator, a startup accelerator based in Mountain View, California. After Y Combinator’s demonstration day in August, the culmination of the three-month program, Momentus will announce plans to attract investment, including its fundraising goal, Kokorich said.

Kokorich, who founded a home products retail chain in Russia before moving to the United States, is also a co-founder of Astro Digital, an Earth imaging and analysis firm based in Mountain View, and an investor in Helios Wire, a satellite-enabled internet of Things startup in Vancouver.

Momentus is not alone in seeing the promise of water as a propulsion source. Deep Space Industries sells Comet, a water-based small satellite propulsion system. Tethers Unlimited offers Hydros, a water electrolysis thruster. And the Aerospace Corp. built water-fueled thrusters for the NASA Ames Research Center’s Optical Communications and Sensor Demonstration mission launched in November 2017.

Debra Werner is a correspondent for SpaceNews based in San Francisco. Debra earned a bachelor’s degree in communications from the University of California, Berkeley, and a master’s degree in Journalism from Northwestern University. She is...