With the James Webb Space Telescope (JWST) now on and making some spectacular images, you may be wondering how exactly it stores them. Surprisingly, it carries a relatively small 68GB SSD, according to IEEE Spectrum, enough to handle one-day JWST images, but not much more.
While this may seem ridiculously small for a $ 10 billion satellite, there are several reasons why NASA chose the system. For starters, the JWST is a million miles from Earth where it is bombarded by radiation and operates at a temperature of less than 50 degrees above absolute zero (-370 degrees F). Therefore, the SSD, like all other parts, must be hardened by radiation and must survive a grueling certification process.
While not as fast as consumer SSDs, it can still be filled in as little as 120 minutes using the telescope’s 48 Mbps data management and command (ICDH) subsystem. At the same time, the JWST can transmit data to Earth at 28 Mbps via a 25.9 Ghz Ka-band connection to the deep space network.
This means that while it collects a lot more data than Hubble ever has (57 GB compared to 1-2 GB per day), it can transfer all that data to Earth in about 4.5 hours. It does this for two 4-hour contact windows each day, each of which allows for the transmission of 28.6 GB of science data. In other words, you only need enough storage to collect the images for a day; they do not need to be kept in the telescope.
There is a puzzle, though. NASA estimates that only 60 GB of storage will be available at the end of the JWST’s 10-year shelf life due to wear and radiation, and 3 percent of the unit is used for data storage. ‘engineering and telemetry. This will leave very little room for the JWST, which will make us wonder if it will have a longevity close to that of Hubble, although it is still strong after 32 years.