The James Webb Space Telescope (JWST) may have had its problems on the ground, but it all paid off. The new space telescope is performing perfectly, and NASA just released the first images captured with the main mirror. With so much more power than Hubble, designers had to give the telescope a good-sized chunk of storage. However, it turns out Webb has just 68GB of solid-state storage, which is barely enough for a day’s work. The JWST is capable of saving 57GB of data per day, depending on its observation schedule.
According to IEEE Spectrum, NASA equipped Webb with an SSD (technically a Solid State Recorder) because they knew it was going to accumulate more data than past observatories. However, Webb is expected to produce about 57GB of science data per day. With room for just a day of data storage, you might wonder why they didn’t use something larger. After all, SSDs measured in terabytes are increasingly common. It comes down to the nature of space: it’s hostile.
Designers had to test Webb’s storage chips obsessively to ensure they would stand up to the harsh conditions of deep space. Unlike Hubble, Webb is deployed out past the orbit of the moon at the Earth-Sun L2 Lagrange point. There are no plans for servicing missions, so robustness was key. NASA expects that Webb’s solid state recorder will experience some degradation over time. In ten years, it may only have 60GB of total capacity. That’s still enough for a day’s work, but only just. By comparison, Hubble only generates 2GB per day when it’s working at full capacity.
When everything works, Webb shouldn’t need to hold onto its data for long. It’s part of the Deep Space Network, an array of spacecraft and relays that help missions like Webb to remain in contact with Earth. Webb has a 25.9GHz channel in the Ka-band for transmitting data home. It has a maximum data rate of 28 megabits per second. The spacecraft has two lower-frequency S-band channels at 2.09GHz. These are used to transmit commands and engineering data at up to 40 kilobits per second. Webb is programmed to only wipe its internal storage after it gets word from home that the transmission has been successfully received.
The James Webb Space Telescope is only getting started working out that little SSD. It launched in late 2021, reaching the perfect orbit with minimal fuel usage. NASA has confirmed that it believes the fuel savings have doubled the telescope’s original 10-year mission.