FLEET's Pumpkin-built Rapid-response CubeSats are Now on Orbit ...

When FLEET Space had a last-minute opportunity to launch 3U  worth of CubeSats on a Rocket Lab Electron launch vehicle, with the caveat that the CubeSats had to be ready in two weeks (!), they came to Pumpkin. We not only typically have nanosatellite-class equipment in stock, but we also have a proven track record of working quickly on projects that require outside-of-the-box thinking.

Rear view of Proxima P1/P2

Front view of Proxima P1/P2

Within two weeks, we needed to come up with a working architecture, source the required components / assemblies, make any modifications required, integrate the FLEET payload and antennas (the pixelated portion above), and provide a software framework upon which FLEET could write their mission software.

Given the very short notice and the desire to maximize the utility of the 3U of volume available on this ride, Pumpkin and FLEET settled on a dual-1.5U mission, with two hardware-identical 1.5U CubeSats. We decided to go with a battery-power-only architecture, as that reduced costs and complexity, and fits within the 1.5U available. Pumpkin immediately embarked on creating a new operating mode for our BM 2 battery; within a few days we had this up and running, and Proxima I/II were thus enabled. The two satellite were built with US and Australian teams working together and remotely, then environmentally tested with no issues, and finally delivered to Rocket Lab for LV integration.

Proxima's Pumpkin components included:

• Solid-wall 1.5U Chassis Walls, with various Proxima-specific modifications
• Solid-wall Base Plate Assembly and Cover Plate Assembly, again with Proxima-specific modifications
• PPM E3 (an update to PPM E1, with more code space) running Salvo RTOS 4
• Motherboard Module (MBM), to host PPM E3 and serve as the mission C&DH processor
• GPSRM 1 GNSS receiver, with built-in Vinti7 orbit propagator (OP)
• BM 2 battery module, with new firmware including sleep mode

 
The Pumpkin bus components occupy around half the volume and mass of each Proxima CubeSat; FLEET's payload(s) occupy the rest. The GPSRM along with its power-efficient ​orbit propagator enable Proxima's mission ops, and the low-power 16-bit PPM E3 PIC24 MCU running Salvo along with the BM 2 and its sleep mode guarantee an efficient use of the battery's available energy. Additionally, some of the code from Stanford University's QB50 project was donated to the Proxima mission, and lives on in Proxima I/II. More information on these CubeSats can be found here.