​
Pleiades Rapid Orbital Verification Experimental System (PROVES)
PROVES, or the Pleiades Rapid Orbital Verification Experimental System, is building Bronco Space’s next CubeSat. Yearling is a 1U scheduled to rideshare on SpaceX’s Falcon 9 Transporter-6, reaching orbit in November 2022. PROVES-Yearling is built on the PyCubed architecture and is intended to serve as a lab bench in space. Yearling is carrying a spresense camera payload for attitude determination in addition to 3 IMUs. We have prioritized modularity and low-cost hardware to create a CubeSat kit that can be made available to other university CubeSat programs to provide a leg up in the development process. The PROVES kit will contain an unassembled structure, the novel Lovelace flight computer architecture, and a software handbook. Universities will also be able to access the open source files for the entire kit as well. The kit aims to bridge the knowledge gap between what undergraduates are taught and the knowledge required to engineer a spacecraft. PROVES-Yearling and our following CubeSat, PROVES-X, are the first steps to accomplishing these goals.
The Evolution of PROVES
This all first started with the Pleiades CubeSat cluster. It began as a collaboration between CubeSat student organizations from Cal Poly Pomona, Stanford, Portland State, and the University of Hawaii at Manoa. The plan involved designing and building a fleet of 6 1U and 2 3U CubeSats that would communicate over a mesh network. This would also have the capability of establishing a visual in-space situational awareness through the use of cameras, primarily in the 3Us. In development of this mission, the need for Bronco Space to develop its ability to rapidly produce 1Us and test the technologies that are planned to be integrated into Pleiades had arose. Hence, PROVES was born.
Since then, the mission for PROVES has now expanded. We now plan to create an open-source 1U CubeSat kit that is versatile enough to meet most 1U missions. This kit will include the Lovelace architecture (Backplane, EPS, ADCS, & C&DH boards), sheet metal structure, and a complete software handbook. Overall, in addition to producing a satellite that will meet the Pleiades CubeSat Cluster mission's needs, Bronco Space will be creating a modular product as well.
Meet the Team
John Geringer
Project Lead
​
PROVES-Y IMU Testing
The Goal
The goal of PROVES is to create a 1U CubeSat platform that is easy to use, affordable, open source, and modular. It is to target educators and University CubeSat programs, since the current platforms for CubeSat's are either very expensive or difficult to find open resources on existing designs. It is also to be used in the Pleiades CubSat Cluster program.
PROVES-Y Engineering Model
Antenna Board
PROVES-Y Assembly
PROVES-Yearling
This 1U CubeSat design runs on the PyCubed hardware and carries along with it a Sony Spresense camera as well as 3 IMU's.
PROVES-Y Structure
PROVES Yearling Radio Communication
The Yearling Cube-Satellite is based on the open source PyCubed flight computer from the Stanford Rex Lab and utilizes HopeRF RFM98 radio modules with the LoRa modulation to send packetized data to ground. While the messages can be heard by anyone with an adequate antenna on the right frequency, decoding is easiest with low cost RFM98 breakout boards such as the Adafruit RFM9X Feather Wing.
PROVES-Y Radio Communication Example
There are a few different categories of packets that ground can receive. The first category is the satellite's beacon which gives a state of health message, which should look like the following:
"KN6NAQ Hello I am Yearling! I am in: ____ power. V_Batt = ___. IHBFJASTME! KN6NAQ".
This message tells the power state of the battery and the voltage measured on the batteries.
The next category of packets is the "Face Data," which transmits the sensors data from each face of the satellite. Temperature sensor, light sensor, gyroscopic sensor, and magnetometer sensor data is available to be received. The face data is put into 6 packets (one for each face). The first face data packet is sent every once in a while, and an acknowledgement must be sent to receive the next packet containing the data for the next face. The acknowledgement must be a singular message of "True" in order for the Yearling Satellite to send an additional packet.
PROVES-Y Comms Test
The radio on Yearling operates at 437.4 MHz, and the user that wishes to communicate with the satellite must also operate their ground station at this frequency. The LoRa modulation operates by sending encoded chirps. These chirps are spread across a small spectrum near the fundamental frequency. The software utilizes a parameter known as a spreading factor, which describes the amount the data is spread across the spectrum. The larger the spreading factor, the more spread out the data is in the spectrum. To properly communicate with Yearling, the spreading factor must be set to 8, as this is what Yearling communicates at. The node of the ground device must be set to 0xFB, while the Destination node must be set to 0xFA. It is also advised that the receive timeout is increased and/or the transmit power is increased, if no packets are received or if the reception is intermittent.
