After the drone that flies thanks to Qualcomm, we learn that the Perseverance rover relies on another consumer chip to carry out its mission.
This time from Intel, the chip is an Atom processor from the “Bay Trail” generation. But while the “drone” mission was a bonus, that of the Intel chip is much more critical because it controls the flow of images from the 23 cameras that equip the rover.
Perseverance is equipped with two storage units for images called “data storage units” or DSU. Each DSU consists of a pure storage part controlled by a motherboard designed by Compulab, a COMEX-IE38.
Costing just $ 150 each, these cards each feature 8 GB of RAM and an Atom E3845, a 64-bit, quad-core x86 CPU clocked at 1.91 GHz, displaying a TDP of 10 W (12 W for the total envelope). ).
It is this CPU, which receives the raw images (RAW) sent by the cameras, which compresses them, sometimes assembles them (panoramas), sends them to the SSD controller integrated on the card (a Phison PSS4A111-8G), and them stores on a 480 GB flash memory SSD.
It is on these two units representing a total of 960 GB that the images are stored which are then sent to Earth. The software genius of NASA engineers is manifested in the management of data corruption linked to the weak electromagnetic protection of the very thin Martian atmosphere. But while the absence of electromagnetic shielding was of little importance for Ingenuity, whose mission duration cannot exceed a few weeks, it is different for the small Atom from Intel, which must manage the images of Perseverance for years. .
A proven processor
Like Ingenuity’s processor, a Snapdragon 801, launched in 2014, Intel’s Atom E3845 is an “old” chip since it was launched at the end of 2013. Engraved in 22 nm, this processor is nevertheless still in the catalog. from Intel. At the time of 5 nm engravings (10 nm at Intel), why keep such a chip? Because it is tried. More than pure power, NASA engineers are looking for reliable components.
And far from targeting (at the time) Netbooks and other inexpensive laptops (the Atom were never wrath of war), this E3845 was qualified by Intel engineers to be used in circles “Automotive”, “Embedded” and “Industrial”.
Notices which indicate that the chip is made to withstand large variations in temperature and condensation. Intel does not joke with this kind of specifications since as part of the electromagnetic robustness tests of its prototype DG1 graphics card, whose evolutions must be integrated into the supercomputers, Intel even carried out irradiation tests in the accelerator. particle from Los Alamos, New Mexico (USA).
This is not an isolated case: Intel’s enterprise SSDs, like the D7-P5510, all go through the Particle Accelerator to test internal data correction hardware and software systems!
The strict protocols surrounding Intel’s “professional” chips mean that its Atoms are also closely studied by the space community in CubeSat, these low-cost miniature satellites. NASA laboratory experiments have shown that even exposed to levels of 5 MeV-cm² / mg, several chips, including that of Intel, “Continue to function properly” even after nasty treatments. Not yet enough to replace armored processors for critical parts (navigation systems, etc.) but largely enough to pilot simple missions.
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Because in addition to the hardware, this kind of proven chip – almost eight years of service! – also has a long software history. Here again, more than the power or the complexity, it is the robustness of the solution that takes precedence. When you’re several hundred million kilometers from Earth, you don’t have to be the fastest, you have to know how to “be and last”.