ESA Document - Emits - ESA

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HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 197 of 422
The present and near-future European space computers are based on the SPARC RISC
architecture (ERC32 then LEON2-FT). More powerful rad-hard Power-PCs are currently
available, but under US ITAR control.
The roadmap for the first generation of LEON processor is now stabilized : flight models in 0.18
µm ATMEL technology should be available during the first quarter of 2005, and should fulfill
the needs of the first Aurora missions.
Nevertheless, note that that the US processor available today already provide more processing
power than the LEON will do in 2005: the first generation of radiation-hardened PowerPC 750
from BAE-Systems in 0.25 µm technology provides 240 to 300 MIPS, and a 370 MIPS version
in 0.18 µm is foreseen before 2007.
To lower the gap with the US products, ways to improve of the internal LEON architecture
should be studied. The power PC 750 architecture is far more complex than the LEON
architecture: it includes several independent processing units that allow executing more than one
instruction per cycle. Moreover it also supports level 2 cache.
This kind of architecture is needed to support higher-level operating systems that can guarantee
soft real-time performances like Linux.
The use of COTS processors (mainly Power PC line of products) shall be assessed for noncritical
payloads. The availability of commercial SOI process (see [RD28]), may boost safe use
of high power chips in space, but dedicated development (especially for ASICs) is needed.
3.3.6.1.2 Maintenance, availability
The availability of space qualified electronic components has decreased in the latest years.
Moreover, the evolution of rad-hard technologies after 0.13 Pm is very difficult to predict: it is
not yet known whether or not the hardening techniques at design level will compensate the
increasing SEE sensitivity (see Figure 3-53). Consequently, the gap between commercially
available technologies and radiation-hardened technologies may either decrease or increase.
Figure 3-53: Comparison of present roadmaps for space qualified and commercial microprocessors