Webb Telescope's Mass Simulator

There are a lot of things that happen "behind the scenes" when a space telescope is being built and all of the components are being tested. In this recent photo, two technicians from NASA's Goddard Space Flight Center in Greenbelt, Md. were working with a "Mass Simulator" for the James Webb Space Telescope.

A mass simulator is used to replicate the weight and shape of an instrument and is attached to a main component of a space telescope or satellite to test the satellite's durability and sturdiness. The mass simulator is like a "dead weight" that contains no electronics or optics that the engineering test units contain. For each instrument that will fly on the James Webb Space Telescope, there are both mass simulators and engineering test units created.

Engineering Test Units are working models of the instruments that are used for testing and validation in laboratory tests, to ensure that they work properly.

The James Webb Space Telescope is the next-generation premier space observatory, exploring deep space phenomena from distant galaxies to nearby planets and stars. The Webb Telescope will give scientists clues about the formation of the universe and the evolution of our own solar system, from the first light after the Big Bang to the formation of star systems capable of supporting life on planets like Earth.

The Webb Telescope project is managed at NASA's Goddard Space Flight Center in Greenbelt, Md. The telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.