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With the James Webb Space Telescope (JWST) up and running and capturing some stunning images, you may be wondering how exactly it stores them.

Surprisingly, it incorporates a relatively small 68 GB SSD, according to the IEEE Spectrum - enough to handle images captured by JWST in a day, but not much longer.

While the size may sound very small for a $10 billion satellite, there are many reasons why NASA chose this solution. For starters, JWST is located a million miles away from Earth, where it is bombarded by radiation and operates at a temperature of less than 50 degrees above absolute zero. So the SSD, like all other parts of the telescope, must be radiation resistant and survive a grueling certification process. 

While in terms of performance it is not as fast as the SSDs that consumers have access to, it can nevertheless fill up in just 120 minutes via the telescope's 48 Mbps command and data handling (ICDH) subsystem. At the same time, JWST can transmit data back to Earth at 28 Mbps via a 25.9 Ghz Ka-band link to the Deep Space Network. 

This means that while it collects much more data than Hubble (57GB compared to 1-2GB per day), it can transfer all this data back to Earth in about 4.5 hours. This is done daily during two time intervals, each lasting 4 hours, which allows for the transmission of 28.6GB of scientific data. In other words, there is only a need to store the images captured in one day, with no need for further storage on the telescope itself.

However, there is an issue since NASA estimates that eventually out of 68GB, only 60GB of storage will be available at the end of JWST's 10-year life due to wear and tear and radiation. The 3% of SSD is used to store engineering and telemetry data making us wonder if eventually Webb will be able to match even close to the longevity of Hubble - which is still operational after 32 years.

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