WorldView Legion’s Custom Dispenser Enables Maximum Design Flexib...

This post is part of a four-part series on the industry-leading innovation behind Maxar's WorldView Legion satellites. To read the innovation blogs published to date, please go here.

There's a lot of engineering that goes into launching multiple satellites into orbit, and certain choices can have a significant impact on the final satellite design.

One important decision is what kind of dispenser to use. The satellite dispenser is a critical mechanical part that secures the satellites to the launch vehicle, protects them during launch, and helps deploy them into orbit. Many launch providers offer their own dispensers for use, requiring only that the satellites are designed to properly interface with that specific dispenser design.

While this option is more convenient, it results in an important trade-off: you must make design choices for the satellite based on the needs of the dispenser. That's a trade-off that the WorldView Legion team didn't want to make.

"Early on, we felt that when you design your own dispenser, you have more freedom," said Wen Lee, a mission assurance engineer at Maxar who contributed to the dispenser design and development. "It gives us more freedom to design a spacecraft suited for the mission without being limited by the requirements of the dispenser interface offered by the launch provider-in the end, it also costs less."

Design flexibility is necessary when building a next-generation satellite, so the team decided to design and build a custom dispenser that was optimized for the final design of the satellite and the plan for orbital insertion. That may sound simple on the surface, but it was a complex project with little room for error.

The first challenge was the design itself. The program required a dispenser that was strong, yet lightweight. The team iterated various designs until they identified one that maximized the removal of dead weight without sacrificing structural stability while maximizing the usage of launch vehicle capacity. The current dispenser design will hold up to 9,300 lbs of payloads.

With the design finalized, the next challenge was manufacturing the part. As it turns out, this dispenser would represent the largest machined part ever designed and assembled by Maxar.

"Most of our experience at Maxar is in graphite composites, which is the material used to make most of the parts in our satellite buses," said Lee. "We didn't have a lot of experience with large aluminum hardware, so this was a first-of-a-kind project for us."

To make the dispenser, the team purchased large ingots of specialized composition aluminum, forged them into rough shape with proper treatment for high strength and durability, and machined the forged material into the major components for the assembly. The project team worked closely with Maxar's supplier procurement team to find new forging and machine shop partners, Scot Forge and Tech-Max Machine, Inc., capable of working aluminum at this scale.

Adding pressure to the project was the fact that there was no margin for error. The aluminum material was expensive and comes with a long lead time to order, so the team would get one shot at making the parts. Maxar had to trust Tech-Max and Scot Forge to get the job done right the first time. Maxar also collaborated with Tech-Max as they adapted their manufacturing and inspection processes for the larger hardware. In the end, both suppliers delivered, creating high-quality parts that were successfully assembled at our facility in Palo Alto, California.

"The effort that we went through in terms of design and finding the partners capable of doing this type of forging and machining is the kind of experience we can pass on to future projects," said Lee. "We've had great teamwork on this program, and I'm impressed with the outcome."

This custom dispenser was successfully used in the May 2024 launch of our first two WorldView Legion satellites, which have collected their first images. We will use this design again in the upcoming second launch in August 2024 and our third launch in the near future. Future customers of the Maxar 500^TM series bus, which was created based on the innovations Maxar invested in for the WorldView Legion program, will benefit from this custom dispenser design as it allows for up to eight satellites to fit inside the fairing, offering opportunities to launch more spacecraft in one constellation or to share the cost of launch with other companies.