The James Webb Space Telescope can generate nearly 60GB of data daily

Shawn Knight

Posts: 14,332   +163
Staff member
In a nutshell: Unlike Hubble which orbits close enough to Earth for astronauts to reach if need be, the new James Webb Space Telescope is roughly a million miles from home. That makes it virtually unserviceable (at least in the near term), meaning NASA had to equip it with only the most reliable and hardened hardware before sending it off into space.

All data collected by Webb is stored locally on a 68GB solid-state drive, and three percent of the space is reserved for engineering and telemetry data. All things considered, Webb can collect up to 57GB of science data per day depending on the target it is observing.

Webb needs to offload its data daily in order to avoid running out of room. It does this via a 25.9-gigahertz channel on the Ka-band at speeds up to 28 megabits per second. The observatory also uses two channels in the S-band including a 2.09-GHz uplink that receives future transmission and observation schedules from Earth at 16 kilobits per second and a 2.27-GHz, 40-kb/s downlink to send engineering data back home.

For comparison, Hubble can generate up to 2GB of data daily.

Webb is part of the Deep Space Network (DSN), a global communications network with ground facilities located in the US, Spain and Australia that supports various spacecraft missions. All of its communications channels employ the Reed-Solomonerror-correction protocol, which is also used in QR codes and Blu-ray / DVDs.

Webb will only wipe its SSD to free up space after it receives confirmation that its existing data has successfully made it to Earth.

Webb's SSD shouldn't degrade too much over time, either. By the end of its planned 10-year mission, NASA expects it to still be able to hold around 60GB of data.

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BadThad

Posts: 1,141   +1,341
Not a big deal that it's small compared to what we're used to. It's cranking out data just fine! Keep the images coming!
 

hahahanoobs

Posts: 4,601   +2,563
It used less fuel during the 1.4M mile distance than intended so the estimate is now closer to it lasting 20 years! We're gonna see some wild stuff.
 

Uncle Al

Posts: 9,090   +8,127
As great as it is, 20 years seems to be a short time. I wonder if they are considering some plans for eventually being able to refuel (changing out the nuclear cells or motor) to extend it's lifespan by another 20 years or so. It would certainly seem prudent considering the investment there .....
 

Lew Zealand

Posts: 2,218   +2,757
TechSpot Elite
As great as it is, 20 years seems to be a short time. I wonder if they are considering some plans for eventually being able to refuel (changing out the nuclear cells or motor) to extend it's lifespan by another 20 years or so. It would certainly seem prudent considering the investment there .....

While that wasn't part of the planning I'd hope that 5 years of cool science might convince someone at NASA to come up with a refueling/repair mission plan. Another decade or so is a nice amount of time for tech improvements to be developed for this kind of solution.

Of course if the mirror's expected micrometeor impact degradation is part of that 20 year life expectancy, maybe just getting a new one up there in 20 is a better plan...

The Hubble is already over 30 years old...
 

wiyosaya

Posts: 7,961   +7,006
As great as it is, 20 years seems to be a short time. I wonder if they are considering some plans for eventually being able to refuel (changing out the nuclear cells or motor) to extend it's lifespan by another 20 years or so. It would certainly seem prudent considering the investment there .....
JWST does not have nuclear cells, and all the electricity it needs is provided by Solar arrays. According to this post https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus/jwst-propulsion
the propellant is hydrazine and dinitrogen tetroxide as the oxidizer.
 

wiyosaya

Posts: 7,961   +7,006
While that wasn't part of the planning I'd hope that 5 years of cool science might convince someone at NASA to come up with a refueling/repair mission plan. Another decade or so is a nice amount of time for tech improvements to be developed for this kind of solution.
I was thinking the same thing about the technological improvements.
Of course if the mirror's expected micrometeor impact degradation is part of that 20 year life expectancy, maybe just getting a new one up there in 20 is a better plan...
With the tech improvements in 20-years, it would likely be far cheaper just to put up a new scope - IMHO.
The Hubble is already over 30 years old...
And still operating reasonably well, too.
 

Ojref

Posts: 37   +49
The storage is radiaton hardened, has about double cell redundancy and in a raid 1 - like configuration so its also path redundant. Radiation hardening for space requires a lot of effort to make it resistant, compact as physically possible and light.
 

DjoCoeur

Posts: 45   +28
That's actually 3,5 megabYtes per seconds.
Generating 7,5 gigabYtes daily.
Not as impressive in bytes, instead of bits.