Tamarack Global Files Fifth Dedicated Vehicle for Impulse Space, the Tom Mueller Propulsion Startup

Tamarack Global has filed its fifth dedicated investment vehicle for Impulse Space, Tamarack Global Impulse Space V LP at $5.6 million, according to AngelLinx Intelligence data from August 18. The filing marks the latest in a series of incremental bets from Tamarack on the commercial in-space propulsion company founded by Tom Mueller, the engineer who designed SpaceX's Merlin engine.

The Company: Impulse Space

Impulse Space raised $300 million in a Series C round led by Linse Capital, with participation from returning investors including Tamarack Global, Founders Fund, Lux Capital, RTX Ventures, DCVC, Airbus Ventures and others. Total funding raised by the company now exceeds $450 million across seed, Series B and Series C rounds. The company is developing its Helios high-energy kick stage, a propulsion vehicle designed to deliver payloads to medium Earth orbit, geostationary orbit and beyond. Tom Mueller's engineering credentials give the company access to both deep technical talent and the investor networks that form around credible founders in the space sector.

Five Vehicles, One Conviction

Five successive dedicated SPVs from the same investor represent a degree of concentration unusual even in deep tech. For Tamarack, the repeat filings suggest a sustained conviction that Impulse Space's propulsion infrastructure will become foundational to the commercial satellite economy, and that each subsequent round offers a sufficiently attractive entry point to warrant a fresh vehicle. When an institutional investor builds a multi-vehicle history with a single company, it is one of the strongest signals the market can produce about long-horizon confidence in that company's trajectory.

What This Means for Founders

For founders in deep tech and space infrastructure, Tamarack's SPV series illustrates how institutional conviction compounds: a first-check investor building a dedicated position through five consecutive vehicles sends a signal that no single portfolio allocation can replicate. Deep tech founders can find investors with long-horizon conviction on AngelLinx.

Find investors backing deep tech and space startups @ angellinx.ai/register.

AngelLinx Intelligence | angellinx.ai