The Raspberry Pi Foundation has published a note about planned upgrades to the two AstroPi devices aboard the International Space Station. Based on the Raspberry Pi 2 Model B+, the AstroPi is hardened to withstand the rigours of space. The upgrades include optical filters, Wifi Dongles, and larger SD cards.
Optical Filters for the AstroPi? Why?
These help to maximise the passage of infrared (IR) light passed to the cameras mounted on the “bottom” of the Astro Pi devices. These then allow the AstroPi to observe IR information through one of the ISS observation ports. These filters are the same material shipped with the Pi NoIR camera. (Yes, the name is nuts as the camera has No IR Filter, not that it can’t do Infrared photography. The filters are precision laser cut to fit around the heatsink pillars on the back of the AstroPi.
Why the larger SD cards?
Previously the data transfer to and from the devices happened through the ISS “socknet” (a space-borne sneakernet, as astronauts don’t wear sneakers aboard). This required astronauts to physically move the cards and copy data using a laptop. Last year the AstroPi devices completed testing to connect to the ISS LAN, allowing data downloads directly from the Raspberry Pi. So the larger cards are not to minimise the astronauts time by transferring larger data payloads.
If you’re taking pictures of the earth, you’re going to need somewhere to store them. Carl Sagan‘s Pale Blue Dot isn’t a lot of help if you want to analyse data in more detail. So you’re going to need more pixels, and more pixels require more space to store them. Hence the larger SD-cards. These will store larger volumes of data, holding more information until a download window is available to Earth.
The cards are Samsung Evo MB-MP32DA/EU devices, which are the European packaged version of the card. These are not your average run of the mill SD cards. They protect data from X-rays, water, heat and magnetism.
And that Wifi dongle?
The Raspberry Pi 2 Model B+ doesn’t have the onboard WiFi that the later Pi 3 has. So Wifi to allow the devices to roam around the ISS needs supporting, a dongle connected to a USB port allows this. ESA (The European Space Agency) helped with the dongle selection. The D-Link DWA-171 was chosen as they use that model on other payloads aboard. I guess it helped reduce the qualification time necessary for the upgrade package.
The upgrade packs are shipping in January 2018, possibly on SpaceX CRS 14. You can update your Raspberry Pi using the same components as used on the ISS if you want!