Agile aerospace is a philosophy of spacecraft development that encourages rapid iteration, where the aim is to make small improvements to every spacecraft design instead of exhaustively trying to perfect each one on the first try. The goal of this approach is to continue to optimize spacecraft architecture through an evolution of capabilities.
At Planet, this means frequently releasing new spacecraft designs, testing them in space, and making changes based on the results. We’ve taken an agile aerospace approach since 2012, and have completed 14 major iterations of the Dove spacecraft design with new generations being released at a steady rate.
Getting our first satellites into space quickly—even if they were far from perfect—enabled us to step through the regulatory and launch integration processes, develop our constellation management software, and learn some hard lessons about the challenges of space optical systems before changes became too costly. We were able to bring prospective customers into the loop as well, and received feedback on actual imagery captured by our early satellites that guided our engineering focus in subsequent years.
While we’ve reaped the benefits of this philosophy, it’s worth noting that it does not make sense to apply it to just any project. Taking an agile aerospace approach imposes constraints on how a spacecraft is designed, manufactured, and operated, and we’ve found that it goes hand in hand with a large constellation approach to realizing a mission.
Rapid iteration and testing in space are key to agile aerospace, but are simply not feasible unless the individual satellites are inexpensive to both manufacture and launch. Launches are often shared between satellites from multiple companies, and to keep costs low, satellites must be small and lightweight. To do that, we miniaturize traditional satellite parts to fit inside our shoebox-sized sats—so while our satellites are smaller, they still possess much of the functionality of larger satellites. They should also be available to purchase on short notice, as it’s not possible to build a new spacecraft in three months if the parts take a year to acquire (as is typical with aerospace-grade components).
Fortunately, the consumer electronics industry has been driving the development of highly capable, inexpensive, miniaturized, and fairly reliable components for decades. Adoption of these commercial-off-the-shelf (COTS) parts in lieu of larger, more expensive, less capable aerospace-grade components has enabled us to develop a satellite that’s inexpensive to both manufacture and launch in a short time frame.
All that said, agile aerospace has its own set of challenges. In a highly miniaturized design there is likely no room for redundancy, meaning that if a single critical component fails there is typically not a spare to take its place, which often results in the need to retire the satellite from imaging. This, coupled with the somewhat lower reliability of COTS components relative to their aerospace-grade counterparts, means that the individual satellites are going to be less reliable and possess a shorter lifetime than, say, a $500M bus-sized NASA spacecraft.
So then the question becomes, how do we still manage to meet high standards of image quality and coverage?
While our sats aren’t as reliable as traditional, larger satellites, we fly them as part of a large constellation that creates redundancy across the fleet, removing any risk to reliability. We invest heavily in developing intelligent constellation management software that can detect and react to problems with individual satellites, and reposition them as needed to fill in gaps in coverage. The end result is a constellation that reliably produces a continuous stream of high quality Earth imagery. It’s composed of around 100 spacecrafts that are continually being retired and safely de-orbited—being replaced with the latest versions as they’re released using the most up-to-date technology possible.
“[At Planet,] we take a more hands-on testing approach [to aerospace], which is quite different from the rest of the aerospace sector, which takes a hardcore analytical approach to finding problems and risks in satellite design,” Marshall explained in his 2015 talk at Stanford University. “[Traditional] satellites have done a tremendous service in helping us to understand the planet so far … But if you want to put 150 satellites into space, this model doesn’t really work.”
Planet continues to help drive innovation in the field of aerospace and in New Space—a new movement encompassing the emerging private spaceflight industry.
Watch Will Marshall’s Stanford University talk to learn more about agile aerospace and how Planet is helping to pioneer a new aerospace movement: