Rhea Space Activity raises $6 million to develop GPS-free spacecraft navigation

WASHINGTON — Rhea Space Activity, a Washington, D.C.-based space technology startup, has raised $6 million in a Series A funding round to advance navigation software designed to operate without GPS, the company said.

The round included investors such as Boston Global Space Tech Investors, Iron Prairie Ventures, Blackbird Capital Group, Purdue Research Foundation, New Mexico Vintage Fund and SpaceFund, among others.

Rhea Space Activity said the funding will be used to accelerate development of navigation software that can guide spacecraft in environments where GPS signals are unavailable, including during atmospheric reentry or in deep space.

The company is developing a visual-based navigation system known as AutoNav, which relies on onboard optical sensors rather than satellite-based positioning. “It navigates by taking pictures of moving space objects such as satellites, moons, planets, asteroids and comets,” the company said.

AutoNav was originally developed at NASA Jet Propulsion Laboratory to enable spacecraft to determine their position and trajectory without continuous guidance from Earth. The approach uses images of celestial objects and compares them against known positions to calculate location and movement.

Rhea Space Activity said the system will be tested on a reentry capsule developed by Varda Space Industries that launched to orbit on March 30.

Efforts to develop alternatives to GPS have gained attention as governments and commercial operators look to reduce reliance on satellite navigation systems that can be disrupted or degraded. Optical navigation offers a potential path to greater autonomy for spacecraft operating in contested or communication-limited environments.