German Company to test Radical Reentry Design

Thanks to the weekday newsletter, Payload, we learn that a German-based space startup called ATMOS has received regulatory approval to fly the first test flight of its novel Phoenix reentry capsule.  It's an approach I haven't seen documented before and I'm expecting most of you will find it interesting.  It also makes ATMOS the first European company to attempt a reentry from space. 

During the mission, scheduled to launch on SpaceX’s Bandwagon-3 rideshare mission as early as April, Phoenix will complete two Earth orbits before blasting through the atmosphere and landing in the Indian ocean—without any parachute.

Like all of rocket science, the tradeoffs associated with reentry are brutal, and a higher orbit brings higher speeds which makes the trades harder.  In the case of the Orion capsule or other satellites returning from the moon, they come in much faster than something in Earth orbit.  Yes, if they did a longer retro rocket burn they could reenter at a lower speed, but that comes at the cost of carrying fuel to burn which reduces the payload that can be sent to the moon to start with.  Since the modifications to Orion's mission profile to prevent the kind of heat shield damage the first flight had, it's arguable that a lower speed could have prevented that damage.  

The ATMOS team has come up with totally different approach. 

Unlike other reentry capsules, which use ablative heat shields, Phoenix relies on an inflatable heat shield to protect its payloads from the shock and heat of reentry. It inflates using a two-stage system of nitrogen gas canisters and air intakes to suck air out of the atmosphere, reaching a full diameter of 6 m. The combination of light weight and large surface area make for a slower, cooler reentry. 

Altogether, the 250 kg-class reentry vehicle can carry 100 kg of cargo at full capacity, an order of magnitude more efficient than other reentry technologies.

“It’s a very risky approach, but if it works, then there’s pretty much no technology out there that is as lightweight as ours,” ATMOS CEO Sebastian Klaus told Payload.

Phoenix I is ready to ship to Florida for its first flight. Image: ATMOS Space Cargo

This is a prototype flight of the technology and will carry at least three payloads for paying customers - who will get a discount since it is a prototype flight.  Of the three that Payload describes, at least two seem that they may also be prototypes.  

The company is looking to fly two more missions in '26 and four in '27 with an ultimate goal of one launch every month.  They're also planning on scaling the vehicle up in size, talking about carrying up to 25 metric tons (55,000 pounds) per flight. 

“Think about what you can do with 25 metric tons. You can talk about factories in space. You can talk about catching a complete satellite and bringing it back down to earth. You can think about bringing back a rocket upper stage and making rockets reusable,” Klaus said.