Northrop Grumman engineers assemble the mid-boom assemblies. Photo: Northrop Grumman.

Northrop Grumman has delivered mid-boom assemblies for NASA’s James Webb Space Telescope. Astro Aerospace, a Northrop Grumman business, designed, built and tested the graphite-epoxy assemblies.

NASA’s James Webb Space Telescope is comprised of four major components — the telescope, the integrated science instrument module, the spacecraft and the sunshield. The two boom assemblies will help deploy the large sunshield once Webb is in orbit. Astro Aerospace delivered the assemblies following successful environmental testing at Northrop Grumman’s Space Park facility in Redondo Beach, California.

Northrop Grumman is under contract to NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for the design and development of the Webb telescope’s optics, sunshield, and spacecraft.

The mid-boom assemblies attach to the sides of the spacecraft bus and extend in length to deploy the sunshield. Each one consists of six telescoping graphite-epoxy composite tubes, one nested inside the other, with Astro Aerospace’s tempered pre-curved stainless steel strip, or Storable Tubular Extendible Member (STEM), . According to Astro Aerospace, the mid-booms work much like a deployable car antenna. As the STEM unwinds from its motorized spool, it curls onto itself to form a stiff tube that pushes the nested composite tubes out until the five movable tubes are fully extended and locked out. The tubes are constructed of graphite-epoxy composite material to be lightweight, stiff, and strong to ensure stability with extreme changes in temperature. As the mid-booms extend, they pull out Webb’s sunshield membranes with them, thereby unfolding them. Once the tubes are fully extended, the STEM is retracted, which reels in a cable through pulleys at the tips of the boom, which then separate and properly tension each sunshield membrane.

The James Webb Space Telescope is the world’s next-generation space observatory and scientific successor to the Hubble Space Telescope. The most powerful infrared space telescope ever built, the Webb telescope will observe the most distant objects in the universe, provide images of the first galaxies formed, and study unexplored planets around distant stars. The Webb telescope is a joint project of NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA).