![]() There’s basically nothing darker than the infinite blankness of space and not a lot brighter than an exploding sun. For one thing, the dynamic range is off the charts - that means the difference in magnitude between the darkest and lightest points. What it detects is not really data that humans can parse, let alone directly perceive. Image Credits: NASA/ESA/Hubble Heritage Team So it was designed first and foremost to produce scientific results,” explained Joe DePasquale, of the Space Telescope Science Institute, in a NASA podcast. So it’s not like we can just take a picture and there we have it, right? It’s a scientific instrument. “The telescope is not really a point-and-shoot camera. We use lots of methods to see outside this band, of course, for example X-rays, which we capture and view in a way we can see by having them strike a film or digital sensor calibrated to detect them. The data that comes into the sensors is in infrared, which is beyond the narrow band of colors that humans can see. “Allowing the data to show through with color” ![]() In fact, it doesn’t really even perceive color at all as we understand it. Interestingly, the Webb only has about 68 gigabytes of storage space internally, which you would think would make people nervous if it can send 57 - but there are more than enough opportunities to offload that data so it won’t ever get that dreaded “drive full” message.īut what you see in the end - even that big uncompressed 123-megabyte TIFF image - isn’t what the satellite sees. The Webb might be capturing data and sending it the same day, but both the capture and the transmission were planned long, long before. ![]() But because they’re dealing with mostly known variables, the Webb team plans out their contact times four or five months in advance, relaying the data through the Deep Space Network. This isn’t just a constant stream, though, since of course the Earth spins and other events may intercede. If you’re interested in the specifics, IEEE Spectrum has a great article that goes into more detail on this. There is a second antenna running at the lower S-band - amazingly, the same band used for Bluetooth, Wi-Fi and garage door openers - reserved for low-bandwidth things like software updates, telemetry and health checks. ![]() That gives it about 57 gigabytes of downlink capacity per day. Purely illustrative for a sense of the distances - objects are not to scale, obviously. Here’s an animation from NASA showing how that orbit looks: That’s four times as far as the moon ever gets and a much more difficult proposition in some ways. JWST, on the other hand, is at the second Lagrange point, or L2, about a million miles from Earth, directly away from the sun. That means communication with it is really quite simple - your phone reliably gets signals from GPS satellites much further away, and it’s child’s play for a scientists at NASA to pass information back and forth to a satellite in such a nearby orbit. The Hubble is in a low-Earth orbit, about 340 miles above the surface. ![]() The Webb’s specs have it sending data back at 25 times the throughput of the Hubble - not just bigger images, but more of them … from 3,000 times further away. That’s more than five times the data, but even that doesn’t tell the whole story. The Webb image (as made available post-handling) is 123 megabytes and approximately 137 megabytes. The Hubble image is about 23.5 megapixels, weighing in at 32 megabytes uncompressed. Extraordinary, right? But this detail comes at a cost: data! ![]()
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