Our next big StarFOX milestone is “day in the life” (DITL) testing, where for the first time, StarFOX software will be run on Starling satellites at NASA Ames for a full 24-hour test period. The goal of DITL testing is to go through – as the name suggests – a typical day in the life of the spacecraft, from start to finish, before launch. This lets us confirm that:
- StarFOX runs as expected on the spacecraft processor.
- Spacecraft sensor data and StarFOX output data are being sent to the right places.
- We can upload commands to StarFOX and download StarFOX telemetry.
- Our mission operations procedures cover all of the necessary items required to operate StarFOX day-to-day.
The objective of this first test is to check spacecraft “plumbing” and make sure the (many) data pipes StarFOX relies on are flowing as expected. For example, we need to get images from both of the spacecraft’s cameras, save them to spacecraft memory, then load the correct image into our Image Processing module in a specified format. Matching StarFOX’s inputs and outputs to those of the spacecraft is a complex task and DITL is the first test of that outside of simulation. Similarly, the procedures required to run a StarFOX experiment – including delivery of spacecraft command sequences and StarFOX parameters from us to orbit – will be evaluated for the first time. It’s generally expected that DITL will uncover some problems, but crucially, these are problems we get to fix before launch.
Each tiny arrow above is a pretty complicated interface.
An interesting wrinkle of this first test is that we don’t expect to get useful navigation data. The test will include simulated GPS data but the images will be dark frames (imagine you’ve still got your camera lens cap on), meaning StarFOX can’t use most of its image processing and navigation functionality. Basically, we’re expecting to see a lot of error flags in our outputs but will hopefully observe GPS signals, images and other data being correctly delivered. As part of this, we’ve set up custom parameter tables and command sequences to run as many StarFOX functions as possible with a very limited set of inputs.
It’s hard to do much fancy navigation if all your camera images look like this. (Fun fact: the star tracker lens covers say “remove before launch” very clearly to avoid unfortunate surprises.)
DITL testing is currently scheduled for the second week of February. Several more DITL tests are also planned before launch, potentially leveraging SLAB’s Optical Stimulator for representative image measurements and enabling testing of complete StarFOX functionality. A separate test will explore multi-spacecraft communication and the ability to send files and measurement data between spacecraft, which is a crucial ability for our more complex navigation experiments.
Ultimately, DITL testing is our first big “finish line” in terms of integrating StarFOX with spacecraft software, hardware, and operations, so it’s a hugely exciting milestone towards launch!
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