Impulse Space funding, valuation and investors

Overview

Impulse Space is a Redondo Beach, California company founded in 2021 by Tom Mueller — SpaceX's first employee and chief architect of the Merlin and Draco engines — to solve in-space transportation after launch. The company builds flight-proven Mira agile spacecraft for precision orbital maneuvering and the Helios high-energy kick stage for rapid transfer from LEO to GEO and beyond. Impulse raised $500M in Series D funding in June 2026 co-led by 137 Ventures and BANNER VC at a reported $4.26B valuation, bringing total funding past $1B. Founders Fund and Lux Capital participated. Impulse has flown Mira missions on SpaceX Transporter rideshares, signed a multi-launch Helios agreement with SES, and was named a U.S. Space Force National Security Launch Program provider.

Why Impulse Space is interesting

Founded by SpaceX employee #1 and Merlin engine designer Tom Mueller, Impulse passed $1B raised on a $500M Series D as in-space logistics becomes the downstream winner of cheap launch.

Product & use cases

Two core vehicles: Mira (high-thrust maneuverable spacecraft with eight Saiph nitrous-based thrusters for hosting, deployment, and repositioning) and Helios (kick stage with Deneb LOX/methane engine delivering up to 4–5 tons from LEO to GEO in same-day timelines). Vertically integrated propulsion and composite tanks.

• Last-mile orbital delivery after rideshare launch to precise slots
• GEO transfer for communications satellites (SES multi-launch agreement)
• Defense and national-security orbital maneuvering and servicing
• Deorbit and space-traffic management for constellation operators

Key facts

• Series D (June 2026): $500M co-led by 137 Ventures and BANNER VC — total funding $1B+
• Founder Tom Mueller was SpaceX employee #1 and Merlin/Draco engine lead
• Mira flight-proven on SpaceX Transporter-9; Helios first flight targeted 2026–2027
• SES multi-launch agreement to lift four-ton satellites from LEO to GEO via Helios
• Named U.S. Space Force National Security Launch Program provider (2026)

Funding history (newest first)

Investors in our directory

Funds linked from Impulse Space's profile — open a fund page for stage focus and related deal articles.

Competitive landscape

Edge: Tom Mueller's propulsion pedigree plus flight-proven Mira platform — team designed the most reliable rocket engines in history and applies same vertical-integration philosophy to in-space mobility.

Falling launch costs create demand for everything that happens after orbit insertion. Impulse targets the 'plumbing' layer — less glamorous than launch but essential as constellations and defense payloads multiply. Mueller's track record and $1B+ raised give credibility competitors in in-space mobility lack.

• Momentus direct

  In-space transportation via Vigoride; faced operational setbacks while Impulse achieved larger orbital maneuvers.

• Rocket Lab (space systems) adjacent

  Launch plus Photon kick stage; Impulse focuses purely on post-launch mobility at larger delta-v.

• SpaceX (internal transfer) adjacent

  SpaceX could extend Starship or dedicated tugs; Impulse bets specialized in-space vehicles win the logistics layer.

• Astroscale adjacent

  Orbital servicing and debris removal; overlaps on maneuvering but different primary mission (servicing vs. transport).

Notable stories

• Tom Mueller founded Impulse because 'launch mostly being solved' — the next opportunity is moving payload and cargo around in space, extending to lunar landers (Sourcery VC tour, 2026).
• Impulse's Mira performed two of the largest orbital maneuvers ever by a nitrous-based propulsion system — validating Mueller's bet on non-toxic, high-thrust Saiph thrusters.

Industries

Related funding articles

Venture Capital Tracker pieces that cover Impulse Space's financing or category context.

• Impulse Space's $500M Series D: Funding the Plumbing of Orbit