How does NASA know that James Webb is deploying well without any cameras? – Numerama

The unfolding of the james webb telescope continues in space, now more thana million kilometers of our planet (i.e. 2/3 of the distance he has to cover, 1.5 million kilometers). NASA is closely monitoring the deployment of the different structures of the observatory: the heat shield, the secondary mirror and soon, the golden primary mirror. However, it does not broadcast any image of this deployment.

The absence of a camera to film the observatory is explicable : it is notably not possible to film on the side of the mirrors, because this side of the JWST is plunged into darkness. As for the other side, facing the Sun under the shield, the brightness is such that cameras would have problems with glare and contrast. In addition, integrating cameras on the James Webb would have added many challenges during deployment (additional cables, risks of vibrations), when it is already particularly thorough. But then, how does the agency manage to follow the deployment of the James Webb, if there is no visual control?

The observatory is full of sensors

The space agency responded on Twitter on January 6, 2022, on the account @NASAWebb. ” How do we know a deployment is successful? Our spacecraft is equipped with mechanical, thermal and electrical sensors, which provide telemetry data to our ground crews. The mission control center @SpaceTelescope [ndlr : le Space Telescope Science Institute, qui gère la recherche menée avec Hubble et le JWST] also has a special viewing tool to check the status of the telescope. “

We could see what this visualization tool looked like during the live monitoring of the deployment. of the sun visor Where of the secondary mirror.

Unless you can actually see the telescope unfold in its surroundings, space, you can follow his position in real time, using this NASA site. The tool also makes it possible to anticipate the next stages of the deployment and to see that it will not be completely finished with the opening of the large segmented mirror. It will take another 5 months to cool the JWST, properly align the mirrors and calibrate the scientific instruments.

The observatory will have to be placed in orbit around the point of Lagrange L2, where it will be protected from the heat emitted by the Sun, the Earth and the moon – in addition to the action of its heat shield. At 1.5 million kilometers, it will therefore be impossible to repair it.