Abstract
Consistent imaging performance of Planet’s SuperDoves is a key feature as the main goal is for global daily revisits over Earth’s landmass. For such small 3-U cubesat platforms, the thermal environment imposes unique challenges in ensuring the payload remains in focus over not only repeated orbital conditions but other varying operational conditions (downlinks and other pointing manoeuvres).
The modelling and testing on ground of representative space thermal environments is typically done using extensive tests. Whilst this is a common approach of larger platforms and fewer satellites, the variability of the large number of satellites, conditions and dynamics will be prohibitive to perform fully for each satellite in a typical Planet’s constellation. In order to account for the satellite to satellite variability Planet has approached this challenge by reducing the set of on-orbit conditions to a relatively small subset of thermal tests that can be carried out not only on each full satellite but also at the telescope level in air. This is leveraged by quick iteration in production and including automation for test and analysis of results.
In this work, we compare some of the satellites on 2 flocks already on-orbit by relating them to their ground focus test results and to other telescopes which are currently being tested and that will be launched later on this year. Using this approach Planet quickly iterates in assessing and predicting the behaviour of the image performance and variance across flocks and ensure that satellites will be in focus for operational conditions.
Focus Characterization of SuperDoves: On-ground and On-orbit First Light
Consistent imaging performance of Planet’s SuperDoves is a key feature as the main goal is for global daily revisits over Earth’s landmass. For such small 3-U cubesat platforms, the thermal environment imposes unique challenges in ensuring the payload remains in focus over not only repeated orbital conditions but other varying operational conditions (downlinks and other pointing manoeuvres).
The modelling and testing on ground of representative space thermal environments is typically done using extensive tests. Whilst this is a common approach of larger platforms and fewer satellites, the variability of the large number of satellites, conditions and dynamics will be prohibitive to perform fully for each satellite in a typical Planet’s constellation. In order to account for the satellite to satellite variability Planet has approached this challenge by reducing the set of on-orbit conditions to a relatively small subset of thermal tests that can be carried out not only on each full satellite but also at the telescope level in air. This is leveraged by quick iteration in production and including automation for test and analysis of results.
In this work, we compare some of the satellites on 2 flocks already on-orbit by relating them to their ground focus test results and to other telescopes which are currently being tested and that will be launched later on this year. Using this approach Planet quickly iterates in assessing and predicting the behaviour of the image performance and variance across flocks and ensure that satellites will be in focus for operational conditions.