Stoke Space Secures $9M Seed Funding for Reusable Rockets

The Pursuit of Full Reusability in Space Launch

A growing number of launch companies believe that reusability is key to reducing both the expense and the timelines associated with space access. SpaceX and Rocket Lab have already demonstrated the viability of reusable first stages, responsible for propelling payloads towards the edge of space. Now, Stoke Space Technologies asserts it is developing a reusable second stage, capable of delivering payloads to orbit and beyond, and has secured $9.1 million in seed funding to achieve this goal.

Challenges of Second Stage Reusability

Designing a first stage for safe return to Earth presents significant engineering challenges. However, its limited altitude and velocity, compared to orbital speeds, simplify the process. The second stage, assuming responsibility after first stage separation, must accelerate and precisely guide the payload to its intended orbit. This typically involves traveling much farther and at considerably higher velocities when attempting to descend.

Stoke Space Technologies contends that creating a reusable second stage isn't merely feasible, but essential for establishing a cost-effective space economy capable of supporting decades of industry expansion. The company’s team boasts prior experience with the New Glenn and New Shepard vehicles and engines at Blue Origin, the Falcon 9’s Merlin 1C engine at SpaceX, and other notable projects.

Operational Reusability as a Core Principle

“Our design philosophy centers on creating hardware that isn’t just reusable, but operationally reusable,” explained Andy Lapsa, co-founder and CEO of Stoke. “This means achieving rapid turnaround times with minimal refurbishment required. This level of reusability must be integrated into the design from the outset.”

Stoke Space Technologies has revealed that its vehicle will utilize a ballistic reentry and powered landing. However, the company has not yet detailed the specific engineering approaches or methods it will employ to safely bring down several tons of sensitive equipment from an altitude of 400 kilometers while traveling at approximately 28,000 km/h.

Balancing Complexity and Cost

Given the extreme speeds involved, reentry poses substantial risks. Therefore, sufficient fuel reserves for both landing and deceleration are crucial. Increasing fuel capacity, however, adds mass and complexity to the vehicle, potentially reducing its payload capacity.

“It’s acknowledged that any reusable system will inherently be more complex than its expendable counterpart,” Lapsa stated. “However, when optimizing for overall mission cost and availability, this added complexity is a worthwhile trade-off.”

The Economic Benefits of Second Stage Reuse

Other launch providers have highlighted the significant financial losses incurred during reentry. Currently, preserving the first stage remains the most practical approach. Recycling the second stage, while challenging, could dramatically lower launch costs.

Stoke Space Technologies aims not only to recover the upper stage but to prepare it for immediate reuse within a single day. “All launch hardware will be reused repeatedly with aircraft-like regularity – zero refurbishment with a 24-hour turnaround,” Lapsa asserts.

Ambitious Goals and Future Expansion

Considering the stresses a rocket endures during ascent and landing, the claim of “zero refurbishment” may seem unrealistic to some. While SpaceX achieves relatively quick turnaround times for its reusable first stages, immediate refueling and relaunch are not currently possible.

Furthermore, Stoke Space Technologies intends to extend its reusable-rocket services beyond low-Earth orbit, catering to missions targeting geosynchronous orbit, translunar trajectories, and even interplanetary destinations.

“Initially, missions to GTO, GEO direct, TLI and earth escape will utilize partially reusable or expendable vehicles, depending on mission needs. These vehicles will be the same ones previously used on fully reusable missions to LEO. The design is scalable to full reuse for these missions – and potentially for extraplanetary landers – in future iterations,” Lapsa explained.

Funding and Future Development

These are undeniably ambitious objectives, and some may view them as unrealistic given the current state of rocketry. However, the industry has progressed rapidly in recent years, driven by similarly ambitious goals.

The $9.1 million seed round secured by Stoke Space Technologies will facilitate the achievement of its immediate milestones. However, substantial additional funding will be necessary to cover the extensive costs of development and testing.

The investment round was spearheaded by NFX and MaC Ventures, with participation from YC, Seven Seven Six (Alexis Ohanian), Liquid2 (Joe Montana), Trevor Blackwell, Kyle Vogt, and Charlie Songhurst, among others.