Building a space telescope to see the light from the earliest stars of our universe is a pretty complex task. Although much of the attention goes to instruments and the giant mirrors on NASA's James Webb Space Telescope, there are other components that have big jobs to do and that required imagination, engineering, and innovation to become a reality.

For example, engineers working on the Webb telescope have to think of everything from keeping instruments from overheating or freezing, to packing up the Webb, which is as big as a tennis court, to fit inside the rocket that will take it to space. Those are two areas where the "DTA" or Deployable Tower Assembly (DTA) plays a major role.

The DTA looks like a big black pipe and is made out of graphite-epoxy composite material to ensure stability and strength with extreme changes in temperature like those encountered in space. When fully deployed, the DTA reaches ten feet in length.

The DTA interfaces and supports the spacecraft and the telescope structures. It features two large nested telescoping tubes, connected by a mechanized lead screw. It is a deployable structure that is both very light and extremely strong and stable.

The Webb telescope's secondary mirror support structure and DTA contribute to how the telescope and instruments fit into the rocket fairing in preparation for launch. The DTA allows the Webb to be short enough when stowed to fit in the rocket fairing with an acceptably low center of gravity for launch.

Several days after the Webb telescope is launched, the DTA will deploy, or separate, the telescope mirrors and instruments from the spacecraft bus and sunshield. This separation allows the sunshield to unfurl and shade the telescope and instruments from radiant heat and stray light from the sun and Earth.

The DTA was designed, built and tested by Astro Aerospace - a Northrop Grumman Company, in Carpinteria, California.

The James Webb Space Telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. The Webb telescope is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency.

ISIM Passes Severe-Sound Test
A critical part of NASA's James Webb Space Telescope successfully completed acoustic testing during the week of Aug. 3. The Integrated Science Instrument Module, or ISIM, passed all of the "severe sound" tests that engineers put it through.

The Integrated Science Instrument Module (ISIM) is one of three major elements that comprise the Webb Observatory flight system. The others are the Optical Telescope Element (OTE) and the Spacecraft Element (Spacecraft Bus and Sunshield).

The ISIM was subjected to the acoustic test at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The ISIM was tested at five different sound levels to demonstrate it could survive the noise and vibrations it will experience when the Webb telescope is launched in 2018 aboard an Ariane 5 rocket. The sound experienced during launch comes primarily from the solid rocket motors of the launch vehicle.

At Goddard, the engineers use the Acoustic Test Chamber, a 42-foot-tall chamber, with 6-foot-diameter speaker horns to replicate the launch environment. The horns use an altering flow of gaseous nitrogen to produce a sound level as high as 150 decibels for two-minute tests. That's about the level of sound heard standing next to a jet engine during takeoff.

During the acoustics test, the speakers can still be heard outside of its insulated massive metal doors.

Following the acoustics test, the ISIM was pushed back into the Spacecraft Systems Development and Integration Facility (SSDIF) clean room so it could be un-bagged, and inspected. Once engineers made sure the ISIM passed the acoustics test, it was re-bagged and moved to the Electromagnetic Interference or EMI facility for electromagnetic interference testing.

The ISIM is just one of the many Webb telescope components that continue to be tested as the observatory begins to come together this year.

The James Webb Space Telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency.