Launching in 2021, NASA’s James Webb Space Telescope will complement and extend the discoveries of the Hubble Space Telescope. Earlier this month, NASA blogged about a successful deployment test of Webb’s mission-critical secondary mirror.

According to NASA, “In order to do groundbreaking science, NASA’s James Webb Space Telescope must first perform an extremely choreographed series of deployments, extensions, and movements that bring the observatory to life shortly after launch. Too big to fit in any rocket available in its fully deployed form, Webb was engineered to intricately fold in on itself to achieve a much smaller size during transport.

Technicians and engineers recently tested a key part of this choreography by successfully commanding Webb to deploy the support structure that holds its secondary mirror in place. This is a critical milestone in preparing the observatory for its journey to orbit. The next time this will occur will be when Webb is in space, and on its way to gaze into the cosmos from a million miles away.”

NASA reports that the secondary mirror will sit in front of Webb’s 18 primary mirrors, collecting light into a focused beam which is then sent down to the tertiary and fine steering mirrors, and ultimately to instruments including a near-infrared camera, near-infrared spectrograph, mid-infrared instrument, and fine-guidance sensors/near-infrared imager and slitless spectrograph. 

The mirrors and instruments make up the optical elements that will ensure a successful 5-10 year mission for Webb.

The Webb workhorse: the 18-segmented primary mirror

One of the most compelling components of Webb is that its primary mirror made of 18 separate ultra-lightweight beryllium segments will unfold and adjust to shape after launch. This 18-segmented mirror is critical to the function and mission of the telescope. A telescope’s primary mirror is the workhorse of any telescope—it’s the mirror that gathers most of the light. The bigger the primary mirror, the more light it collects. A larger primary also produces an image with higher resolution and more detail.

Sharper images will help Webb pursue its mission goals including to: 

• Search for the first galaxies or luminous objects formed after the Big Bang

• Determine how galaxies evolved from their formation until now

• Observe the formation of stars from the first stages to the formation of planetary systems

• Measure the physical and chemical properties of planetary systems, including our own Solar System, and investigate the potential for life in those systems

For size comparison, Hubble Space Telescope’s primary mirror is 2.4 meters, while Webb’s primary mirror is 6.5 meters. A mirror of this size has never been launched into space. 

OpticStudio used to design primary mirror and other critical systems

OpticStudio was used to design the space telescope’s primary mirror. Webb engineers used our software to create the system that will align the telescope’s 18 segments—in space.

Our software was used not only to design the optics for the camera that will help align the 18-segmented mirror in space, but to custom-develop special software that will also be critical for that alignment process.

Image Credits: NASA's James Webb Space Telescope