The James Webb telescope can track targets that travel at over 100 msec - 223% faster than planned

The James Webb Space Observatory has proven its ability to observe space objects more than three times their maximum tracking speed. The DART probe's collision with an asteroid last year helped prove this.

Here's What We Know

James Webb watched as the spacecraft flew into the asteroid to alter the latter's trajectory. The telescope was not supposed to be able to track objects that have such a high angular velocity. But it turned out it could.

The space telescope has a Fine Guidance Sensor (FGS) on board for this purpose. It captures a stationary star and moves it at a speed that matches the speed of the object being tracked. The process is performed until the star disappears from the sensor's field of view. This happens quickly, making observation very difficult.

“On paper”, James Webb can track targets that move at the angular velocity of Mars - 30 ms/s (angular milliseconds per second). However, through experiments, scientists have proved that the telescope can observe objects that move at speeds of up to 67 milliseconds per second.

But that wasn't enough to record a DART collision with an asteroid. In order to track a space crash, the bar had to be crossed at 100 msec/s (360 min/h). To test the system, scientists first used a simulator and then tested the telescope's capabilities on the asteroid 2010 DF1. As a result, James Webb managed speeds of 324 and 396 min/h.

Despite the success, scientists have no plans to use the space observatory in this mode. James Webb will track objects at a maximum angular velocity of 75 milliseconds per second, with the possibility of increasing it to 100 milliseconds per second.

Source: NASA