Our friends at the Swedish Institute of Space Physics (IRF) have successfully landed with their Advanced Small Analyzer for Neutrals (ASAN) instrument on the far side of the Moon, on board the Chinese Chang’E-4 spacecraft.
Chang’E-4 is the first-ever spacecraft to soft-land on the Moon’s far side (the side we usually don’t see), in the Von Kármán crater in the South Pole-Aitken Basin. The ASAN instrument in on board the Yutu-2 rover. This of course means the IRF has beat us in having Sweden’s first scientific instrument on the moon, so our hats are off to them 🌝
This week our new boards arrived. After a bit of grief due to picking a faster crystal than what Atmel/Microchip guarantees will work at 3.3 Volt, we managed to cobble together a test this Saturday evening. Things are looking promising, especially our new rotor grounding method. We shall see how well it works after some more rigorous testing.
There are more things that remain to be seen. For example, we’re hoping the improved shielding in our new fieldmill PCBs will reduce/eliminate how much of any synchronous unwanted signals we pick up. Previous versions would pick up the voltage changes in the IR tachometer signal, from several centimeters away. This because when measuring with 100 MOhm transimpedance amplifiers, any stray dV/dt’s get picked up. If they’re in sync with the rotor’s rotation then that pickup appears as an undesired offset in our signal!
Besides the minor crystal issue, we’ve so far not had much problems with the PCBs. We’re currently focusing on mechanical and software issues, both of which are important for final integration with the lander. Hopefully more on that in the future! For now we’re aiming for more vibration testing at the start of 2019.
The project moves forward. For the last couple of months we’ve kept busy finalizing the design of the instrument, trying to minimize noise and pickup of unwanted signals. We currently have two sets of boards being manufactured, which should hopefully arrive fully assembled in about a month. We’ve also had a much-needed vacation right in the middle of the current heat wave 😅
Next up is providing more accurate mass, center-of-mass and moment of inertia measurements to PTScientists. We’re also working on finalizing the data format, since that decides how much bandwidth we need. So far it’s looking like around 200 B/s while the instrument is running. We can probably cut that down with some compression, at the cost of increased latency. Possibly more on that in a future post.
Just some pictures of the vacuum test setup which our MSc student has built.
The stainless steel mesh allows us to apply some known static electric fields to calibrate and evaluate the performance of our instrument.
Likt förra året så medverkar vi i Musikhjälpen 2017! Till förmån för utsatta barn så auktionerar vi ut en möjlighet att få ett meddelande inetsat på ett kretskort i vårat instrument, som är tänkt att landa på månens yta! Gå in och buda på Tradera-auktionen genom att klicka på denna länk.
Vi kommer även att medverka i själva programmet Musikhjälpen klockan ett imorgon kväll dvs Fredag kväll dvs Lördag morgon 01:00. Vi kommer att berätta om vårat projekt samt såklart uppmuntra fler att gå in och buda på auktionen 🙂
Vi höres då!
It has been a hectic autumn with little time for updates, about time for one!
First of all we paid IRF a second visit, for vibration testing. This turned up one problem, an M4 nut coming slightly lose. To rectify this we’ve invested in torque wrenches and are working on an assembly manual with specified torques for every screw and nut. For the curious, the work-in-progress manual is up on our GitHub account here.
The second bit of news is that we have a master’s thesis student working with us, Clayton Forssén. His job at the moment is to write LabView code parsing output from our prototype instrument. The goal is to get a series of measurements done in our vacuum chamber with the new XYZ E-field applicating cube (a miniaturization of the capacitor plate plywood cube we have used in earlier tests).
The third news is that our deadline has been pushed at least another year into the future. This gives us some much-needed time to fine-tune the design, code, documentation and so on.
That’s all for this update. As always, keep watching this space for more interesting stuff 😎