Webb Telescope's Secondary Mirror Unloaded at NASA Goddard
The secondary mirror that will fly aboard NASA's James Webb Space Telescope arrived at NASA's Goddard Space Flight Center in Greenbelt, Md. on Nov. 5, 2012. This photo shows the mirror housed in a shipping canister, being unloaded from a moving truck.
The mirror arrived at their new home at NASA, where they will be residing at the giant cleanroom at Goddard for a while, as technicians check it out.
The mirrors previously resided at Ball Aerospace & Technologies Corp. of Boulder, Colo. who manufactured and packed them.
Unlike the 18 primary mirror segments that make up the biggest mirror on the Webb telescope, the secondary mirror is perfectly rounded. The mirror is also convex, so the reflective surface bulges toward a light source. It looks much like a curved mirror that you'll see on the wall near the exit of a parking garage that lets motorists see around a corner. This mirror is coated with a microscopic layer of gold to enable it to efficiently reflect infrared light (which is what the Webb telescope's cameras see). The quality of the secondary mirror surface is so good that the final convex surface at cold temperatures does not deviate from the design by more than a few millionths of a millimeter - or about one ten thousandth the diameter of a human hair.
The Webb telescope is the world’s next-generation space observatory and successor to the Hubble Space Telescope. The most powerful space telescope ever built, the Webb telescope will provide images of the first galaxies ever formed, and explore planets around distant stars. It is a joint project of NASA, the European Space Agency and the Canadian Space Agency.
To learn more about the Webb's secondary mirror, visit:
www.nasa.gov/topics/technology/features/webb-secondary.html
For more information about the James Webb Space Telescope, visit:
Credit: NASA/Chris Gunn