Meet Rigel: Powering the Next Layer of In-Space Mobility

blog

APR 23 2026

Meet Rigel, a 200 lbf class engine delivering a new layer of in-space mobility between precision maneuvering and high-energy transport.

As the space economy scales, exploration is expanding, government activity is increasing, and missions are pushing further into deep space. In-space operations are requiring increasingly dynamic mobility. The Rigel engine is built to power this next phase of space mobility, delivering a propulsion system for landers, in-space maneuvering, and high delta-v missions.

A Versatile, Workhorse Engine

Rigel combines performance with simplified operations. Its low part count architecture reduces complexity and enables reliable, scalable production at an order of magnitude lower cost than conventional systems, with faster build cycles and easier integration.

Key characteristics of Rigel's design include:

• Nontoxic, storable propellants (nitrous oxide and ethane), which enable fueling in hours rather than days
• Unlimited restartability for multi-phase missions
• Deep throttleability for controlled descent, landing, and precision maneuvering
• Long-duration burn capability for high delta-V maneuvers

By simplifying manufacturing and increasing fault tolerance, Rigel supports higher mission cadence, lower cost per mission, and greater reliability. It can operate as a vehicle's primary propulsion system or be clustered, suited for a variety of mission types.

Rigel can be used for landers, in-space maneuvering, rendezvous and proximity operations (RPO), interception, and other multi-phase missions requiring both a range of thrust and precise control, where reliability is not optional. Its mission set can span operations in Earth's orbits to distant planetary exploration. For civil use cases in particular, Rigel's multi-use nature solves for the challenges of purpose-built, single-mission engines, with both economic and reliability benefits from flying the same engine across different vehicle platforms and missions. Standardizing on a single propulsion architecture builds flight heritage, reduces unit cost, and delivers a manufacturing cadence that legacy systems cannot match.

The Engine that Started It All

Rigel traces back to an engine our CEO Tom Mueller began developing prior to founding Impulse - work that directly shaped the company's early direction. In October 2021, a team of just seven people completed the first successful Rigel hot fire, demonstrating the core architecture and validating the concept early.

As Mira and Helios progressed and Impulse set its sights on the vehicles and missions that come next, we returned to Rigel in 2025. The engine was redesigned and brought back into active development, alongside the buildout of new test infrastructure in Mojave, CA. The team moved from redesign to regular, on demand hot fires in just four months, demonstrating both the maturity of the architecture and the speed of execution behind it.

Joining the Family

Impulse is building a full spectrum of in-space mobility, with propulsion systems spanning from precision maneuvering to high-energy transport. Rigel is a core part of that architecture.

• Saiph (Mira) → precision maneuvering within orbits
• Rigel → throttleable propulsion for rapid operations and landing
• Deneb (Helios) → high-energy transport across orbits

Our growing family of propulsion systems and vehicles is how we're delivering reliable, affordable, end-to-end in-space mobility - and accelerating our future beyond Earth.