Orbit Classification for the Parker Solar Probe (PSP) Mission

There are a number of challenges for the Science Planning Team (SPT) of the PSP mission. The geometry of the celestial bodies and the spacecraft during some of the PSP orbits cause limited uplink and downlink opportunities. To add further complexity, two of the spacecraft payloads, FIELDS and SWEAP, have the capability to write large volumes of data to their internal payload solid state recorder (SSR) while sending a smaller "survey" portion of the data to the spacecraft SSR for downlink. The instrument scientists would then view the survey data on the ground, determine the most interesting data from their payload SSR, and send commands to transfer that data from their payload SSR to the spacecraft SSR for downlink. The timing required for downlink and analysis of the survey data, identifying uplink opportunities for commanding data transfers and downlink opportunities big enough for the selected data within the data collection period is critical.

Detailed orbit activity planning is required in advance for each orbit. The instrument teams will be required to coordinate with the Mission Operations Center (MOC) regarding the availability of downlinks, data volume allocation, power on opportunities, command uplink opportunities, data transfer rate from instrument memory to the spacecraft SSR and the instrument data content in the spacecraft SSR.

We have created an orbit classification scheme using downlink availability and the spacecraft and instrument solid state recorder data deposition. This scheme attempts to capture the patterns that emerge, allowing us to formulate default plans for similar orbits to aid in the science planning process.