If you were designing the JWST today, you would probably also put onboard a GPU. That could be programmed to do some of the scientific work in space to reduce the amount of data that needs to be downloaded.<p>This would allow new types of science (for example, far shorter exposure times and stacking to do super resolution and get rid of vibrations in the spacecraft structure). It would also allow redundancy incase the data downlink malfunctions or is degraded - you can still get lots of useful results back over a much smaller engineering link if you have preprocessed the data.<p>Obviously, if that GPU malfunctions, or there isn't sufficient power or cooling for it due to other failures, data can still be directly downloaded as it is today.<p>Basicly, it adds a lot of flexibility.
I'm curious for anyone who may know the answer... with no mention of encryption, are these streams free for anyone with the equipment to receive? Conversely, what kind of security is in place on JWST for command updates to ensure that some rogue group couldn't cause mischief and send it commands?
Reading this article makes me realise that it would take a relatively small let up in funding such projects to permanently lose the knowledge and expertise it takes to build these fantastic machines.
This is the type of articles we (data junkies) need to see and read! Highly interesting to see the transmission rates, storage capacity and other data related considerations that went through the design of James Webb telescope.
Now, if only there were more funds allocated to antennas/dishes on the DSN (Deep Space Network) [0] to be able to service all ongoing and future space missions, that would be great.<p>[0] <a href="https://eyes.nasa.gov/dsn/dsn.html" rel="nofollow">https://eyes.nasa.gov/dsn/dsn.html</a>
> In addition, according to Carl Hansen, a flight systems engineer at the Space Telescope Science Institute (the science operations center for JWST), a comparable X-band antenna would be so large that the spacecraft would have trouble remaining steady for imaging.<p>Why would a large antenna make the spacecraft less steady? What's the mechanism behind it?
The article didn't go into it I think, but I recall in many satellite missions of this type, there are not only data storage and transmission issues (normal issues you would expect), but also considerations that the antennas and transmission hardware themselves have a certain duty cycle or lifetime that is finite. As in transmission of data consumes that margin.<p>So you have to quite deliberate in considering how much data to be sending, which data, etc. because every GB eats a chunk of the satellite's expected life. (Again, I believe.)
> All of the communications channels use the Reed-Solomonerror-correction protocol—the same error-correction standard as used in DVDs and Blu-ray discs as well as QR codes.<p>I find that somewhat hard to believe, LDPC are well established and much more suitable. I would have expected that they would use a DVBS2 standard code.
> Data gathered from its scientific instruments, once collected, is stored within the spacecraft’s 68-GB solid-state drive (3 percent is reserved for engineering and telemetry data)<p>Hope the SSD does not fail after 32768 or 40000 hours of operation.
This kind of communication seems like an interesting problem for Starlink (or other satellite internet constellations) to solve. What if the satellites had extra antennas pointed outwards and relayed the data back to the ground at high bandwidth?<p>Seems like it would avoid a lot of the issues like atmospheric interference, frequency congestion, and careful placement of receiver infrastructure.
The article isn't as interesting as I thought it would be.<p>> JWST can produce up to 57 GB each day (although that amount is dependent on what observations are scheduled).<p>Just use a lot of hard drives? And delete junk data when it's no longer needed.
> All of the communications channels use the Reed-Solomonerror-correction protocol.<p>I think you don't want to use Reed Solomon for this, but turbo codes or most likely online codes.<p><a href="https://en.wikipedia.org/wiki/Online_codes" rel="nofollow">https://en.wikipedia.org/wiki/Online_codes</a>