![]() ![]() Plus, it needs to be much farther away from earth than Hubble has ever gone. Unlike Hubble which orbits the Earth, JWST is unable to orbit because then its temperatures would vary greatly in sun and shade. Not that’s just something there on JWST itself, which is slightly colder or warmer than it should be,” Barron explained. Because any variation and we’re going to look at something and think ‘Oh, this is a star. “Not just colder, but we need to be able to control the temperatures. But, to be accurate, the mirror needs to keep cold. ![]() The second non-functional requirement of the JWST was to go beyond Hubble in not only seeing invisible light, but in seeing hot infrared light. A solution arose to break the mirror up into smaller hexagons, which can be aligned together to form a honeycomb-shaped mirror. The non-functional requirement became to create a foldable mirror. However, an operational constraint arose that the mirror is so large that it doesn’t fit into any rocket, so it needed to be broken up into pieces. For instance, it needed to be much more powerful and larger than Hubble, but to achieve that it needed a significantly larger mirror. When designing JWST, the design engineers kicked off with the functional requirements, which in turn drove a lot of non-functional requirements. Spitzer, NASA’s first infrared Great Observatory, led the way for Webb’s larger primary mirror & improved detectors to see the infrared sky with even more clarity: /g941Ug2rJ8 It’s not something logical, it’s something physical that has to work properly and I think there are a lot of lessons and a lot of inspiration that we can take from this work into our day-to-day lives.”Īfter 30 years of amazing photos from the Hubble Telescope, there was a demand for new business and technical capabilities, including to be able to see through and past clouds as they are created.Ĭomputer, enhance! Compare the same target - seen by Spitzer & in Webb’s calibration images. “If something goes wrong, if it’s not reliable, then it doesn’t work. “It’s a great platform for demonstrating site reliability engineering concepts because this is reliability to the extreme,” Barron said of the James Webb Space Telescope (JWST). Universe-Scale Functional and Nonfunctional Requirements It’s a real journey into observability at scale. And how NASA was able to trust its automation so much that it’d release something with no hopes of fixing it. At his WTF is SRE talk last month, Robert Barron brought his perspective as an IBM SRE architect, amateur space historian, and a hobby space photographer to uncover the patterns of reliability that enabled this feat. Needless to say, there are a lot of reliability lessons to be learned from this endeavor. Last week we saw the very first, better-than-even-expected images from the James Webb Space Telescope or JWST.Īfter ten years of design and build on a $9 billion budget, this was an effort in testing 344 single points of failure - all before deploying to production, with the distributed system a million miles and one month away. Earlier this year, the single greatest site reliability engineering (SRE) lesson unfolded itself out in space. ![]()
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