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The Curiosity and Perseverance rovers, and the InSight lander, all use the BAE RAD750 processor.

The Ingenuity helicopter uses a Qualcomm Snapdragon 801 processor.

The only other active spacecraft on the surface of Mars is China's Zhurong rover. What processor does it use?

DrSheldon
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    I have a hunch we can look first to high-rad variants of standard products manufactured on the mainland, and we can rule out products from Taiwanese foundries (or those in Japan or Korea or the US...). – uhoh Jun 23 '21 at 02:25
  • Why rule out foundry products? Some have good radiation performance, but since it is not a product spec it can vary from part to part (more properly lot to lot), so the next batch you buy might not be as good. – Jon Custer Jun 23 '21 at 12:59
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    @JonCuster the statement refers to very specific customer-vendor combinations and draws from trends both in the industry and in world affairs. It doesn't rule out foundry, that would be the likely source for a larger technology node = less radiation-sensitive device, it addresses the geopolitics of silicon. – uhoh Jun 23 '21 at 14:55
  • TSMC foundries are at the leading edge - building a fab at the latest node costs way more than most companies (particularly rad-hard focused companies) can afford. Further, your assumption that a larger technology node means a less radiation sensitive device is not accurate. (For example, for the same circuit, a smaller technology node means less total cross section of active regions that would be sensitive to ionizing radiation.) – Jon Custer Jun 23 '21 at 18:50
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    @JonCuster: I believe uhoh's original comment was more about the international politics between China and Taiwan, rather than technology. – DrSheldon Jun 23 '21 at 19:47
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    @JonCuster ...and I'm just going by this answer to What makes Insight's RAD750 processor so radiation resistant? (compared to 1998 iMac's PowerPC 750) "By dividing the die area by the number of transistors, it appears that the transistors are generally larger. Fabrication process size is not a good metric here; it tells you that a manufacturer can make smaller transistors, but does not tell you if the actual size of transistors are smaller. Larger transistors are less susceptible to radiation." You can argue there if necessary. – uhoh Jun 24 '21 at 01:24
  • @JonCuster the charge necessary to change the state of an FET of dimension $D$ is a little complicated; the area scales like $D^2$ but the gate dielectric thickness and threshold voltages both change, so it needs a different SE site to nail down the scaling exactly. But for an ionizing particle track passing through the active area, the charge left in the channel will only be proportional to $D$. The linked answer also explains that latch-up is addressed by moving to SOI. – uhoh Jun 24 '21 at 01:36
  • That is one way to do it, well known since silicon on sapphire. There are many contributions to what makes things rad hard, and many ways to make things hard. – Jon Custer Jun 24 '21 at 02:14
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    This South China Morning Post article might be helpful – BrendanLuke15 Jun 24 '21 at 03:09
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    @BrendanLuke15: Hmmm. That article does clarify that Zhurong and other Chinese space hardware use an operating system called "Kylin", written by the Chinese government. It mentions they have their own CPU "Loongson", but does not clarify if that CPU is in any space hardware. – DrSheldon Jun 24 '21 at 03:42
  • I doubt there'll be an official answer, but from what I could gather SunWise Space Tech company's SoC series is a likely candidate (SoC2012 was used on BeiDou3 Satellites). The fact that the SoC2016 model is restricted from export may also support this. – AlphaD Jun 25 '21 at 08:28
  • I just found a webpage which has this question & some of the comments translated into French – Fred Jun 17 '22 at 17:24
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    On what looks like a forum type website. This unsubstantiated statement: While I believe that the Chinese space chips provider (e.g. CASA, Loongson) are becoming more and more competent, it seems that the Chinese spacecrafts are still using some imported chips (e.g. Microchip/ATMEL AT697 CPU used by the Chang’e-4 lander, Samsung K9F8G08U0M SLC Nand Flash used by the Zhurong rover). – Fred Jun 17 '22 at 17:29

2 Answers2

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China use the Loongson family of microprocessors. Those used to use the MIPS architecture, but now have their own instruction set architecture (ISA): LoongArch.

They've used Loongson for many years now, using the Kylin operating system (mostly).

Erin Anne
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draguoner
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    As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center. – Community May 18 '22 at 01:52
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Just as a starting point, the Wikipedia article for the Loongson processor family points to this paper, which has a few more cool details.

2.2 Loongson X-CPU radiation hardening by design

The paper titled “Loongson X-CPU radiation hardening by design” introduces the design of a radiation hardened processor for space applications. Radiation hardening can be achieved by adjusting the manufacturing process; however, this approach is prohibitively expensive. Radiation hardening by design (RHBD) [18,19] is the most widely used radiation hardening method that does not require adjustments to the manufacturing process.

The authors discuss the RDHB method from multiple aspects, including circular-shape gate layout, guard-ring protect, time and space triple modular redundancy, dual interlocked storage cells, and error detection and correction coding, and apply all of them to the anti-radiation design of Loongson X-CPU. The Loongson X-CPU is a highly integrated, high-performance SoC based on the dual-issue, 32-bit Loongson GS232 CPU core. It was fabricated with 180 nm CMOS technology. The chip operates at 100 MHz and contains a CPU core with separate instruction and data caches, an SDRAM/SRAM controller, a PCI controller, an SPI controller, an interrupt controller, two UARTs, an I2C and WDT interfaces. The chip was tested up to a total dose of 300 krad (Si), and it yielded an SEU error rate better than 1.90362 × 10^−5/device/day. The results demonstrate that the chip can adapt to complex space environments and meet the demands of complicated applications. On March 30, 2015, China launched a new-generation manmade satellite into space for its BeiDou global navigation and positioning network. In this satellite, Loongson X-CPUs are used to perform tasks such as controlling, communication and data processing.

I haven't found a source for the referenced paper, "Loongson X-CPU radiation hardening by design".

0xDBFB7
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