Many launch vendors believe that reusability is the best way to reduce space costs and delays. SpaceX and Rocket Lab showed reusable first stages that take a payload to the edge of space – and now Stoke Space Technologies says it makes a reusable one second Stage, which is taking this payload into orbit and beyond, and has raised a $ 9.1 million launch round to make it happen.
Designing a first stage that can safely return to Earth is not an easy task, but the fact that it will only reach a certain altitude and speed, and not go into orbit at an even higher rate, means that it is easier to to try. The second stage takes over when the first is depleted and accelerates and guides the payload to its target orbit, which generally means that it has traveled much further and goes much faster when trying to come back down.
Stoke believes that not only is it possible to create a second tier that is reusable, but it is critical to building a cost-effective space economy that will enable decades of growth in the industry. The team previously worked on the New Glenn and New Shepard vehicles and engines at Blue Origin, the Merlin 1C for the Falcon 9 at SpaceX, and others.
“Our design philosophy is to create hardware that is not only reusable but also operationally reusable. That means fast throughput times with little processing effort. Reusability of this kind needs to be considered from the start, ”said Andy Lapsa, Co-Founder and CEO of Stoke.
Aside from the fact that the vehicle will perform a ballistic re-entry and motorized landing, Stoke made no comment on the technique or method by which the Herculean feat of bringing a few tons of precision equipment safely from a height of 400 kilometers and would be accomplished to drive around 28,000 km / h. (Though Lapsa mentioned it GeekWire that a “good, powerful, stable injector” is the core of your engine and thus of the system around it.)
At such speeds, reentry can be fatal, so it is hoped that they will save a bit of fuel not only for landing but also for deceleration. This would increase the mass and complexity of the vehicle in front of the payload and reduce its carrying capacity.
“It is true that any reusable system will inherently be more complex than its consumable counterpart,” said Lapsa. “However, if you optimize mission costs and availability, the complexity pays off.”
As other startup companies have pointed out, you burn a lot of money on re-entry, but so far the safest thing to do has been to keep the first stage alive. The second phase is by no means cheap, and any company would prefer to recycle it too – and in fact, if they did so successfully, they could cut the cost of implementation hugely.
The promise that Stoke makes is not just to bring the upper stage home, but to bring it home and have it ready for reuse just a day later. “The entire starter hardware is reused again and again with an airplane-like regularity – no renovation with 24-hour processing time,” explains Lapsa.
Given the wear and tear a missile goes through on ascent and landing, “zero refurbishment” may sound like an impossible dream to many. SpaceX’s reusable first stages can be flipped over pretty quickly, but you can’t just refuel where they landed and hit the button again.
In addition, Stoke would like to offer a reusable missile service beyond the low-earth orbit that most small, lower-cost satellites fly into. Geosynchronous orbit and translunar or interplanetary trajectories are also planned.
“Missions to GTO, GEO Direct, TLI and Erdflucht are initially carried out with partially reusable or dispensable vehicles, depending on the mission requirements. However, these vehicles are the same that may have been used on previous fully reusable missions to LEO. The design is expandable for full reuse for these missions (and / or extraplanetary landers) in future variants, ”said Lapsa.
These are ambitious claims – even given the current state of rocket science, there is good reason to call this unrealistic. But the industry has advanced faster than many would have predicted a decade ago, and seemingly unrealistic ambitions have driven those changes as well.
The $ 9.1 million starting round raised by Stoke will allow it to hit the next milestones, but anyone who follows the industry will know that a lot more money is needed to cover the cost of development and cover tests in a timely manner.
The round was led by NFX and MaC Ventures, among others, as well as YC, Seven Seven Six (Alexis Ohanian), Liquid2 (Joe Montana), Trevor Blackwell, Kyle Vogt and Charlie Songhurst.