Why there are no cameras to capture the unfolding of James Webb
With the final deployment of the James Webb Space Telescope today, you might be disappointed to learn that there will be no photos or videos of the telescope’s deployment.
When the Perseverance rover landed on Mars last year, audiences were treated to breathtaking footage of the rover descending from its descent stage onto the planet’s surface. There was even a video of the landing, showing the remarkable event from multiple angles captured by cameras placed all over the rover’s landing system.
So how come there aren’t similar cameras showing the deployment of the James Webb Space Telescope?
In a recent blog post, NASA has revealed that it plans to put cameras on the telescope to cover its deployment. These cameras could also have been useful in diagnosing any problems that arose during the deployment or operations of the telescope. However, when the proposal was thoroughly examined, the team found that it was not going to work.
“Adding cameras to watch the unprecedentedly complex deployment of a spacecraft as precious as Webb seems like a no-brainer, but in Webb’s case there is more to it than it seems.” Paul Geithner, assistant technical project manager for the Webb Telescope at NASA’s Goddard Space Flight Center, said in the post. “It’s not as simple as adding a doorbell camera or even a rocket camera.”
There are two big challenges with having cameras on Webb. The first is that, because the telescope deploys through an elaborate process, there wouldn’t be a single place where a camera could observe all the deployment processes. There should be multiple cameras and the wiring from those should go through the telescope, which could cause issues.
The other big problem is the sunlight. Webb is designed to reflect sunlight away from its sunny side, so it doesn’t get too hot, but that does mean that side is very bright which would cause constant glare for cameras. On the cold side of the telescope, there wouldn’t be enough light for the cameras to see anything, and these cameras would have to operate in very low temperatures.
Ultimately, the engineers decided that Webb’s other sensors would be more useful than cameras in getting a picture of the telescope’s condition.
“Webb’s built-in sense of ‘touch’ (eg, switches and various mechanical, electrical, and temperature sensors) provide much more useful information than just surveillance cameras,” Geithner said.
“We instrumented Webb as we do with many other unique spacecraft, to provide all the specific information needed to keep engineers on Earth informed of the health and condition of the observatory during all activities. “