Webb Telescope Reaches Critical Milestone on Journey to Space
The primary optic enabling the most powerful telescope ever built is a complex system of segmented mirrors that will unfold to become the largest mirror in space. Testing to prove this amazing feat of engineering can withstand and operate in the harsh temperatures of space is nearly complete—and Harris is playing a critical role.
The mission of NASA’s James Webb Space Telescope sounds like it could have been written for a Star Trek series:
- 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
Today we are at an important milestone on the journey to launching this amazing telescope toward its future orbit around the sun, some million miles away: the wrap-up of a 100-day cryogenic testing to demonstrate how Webb will function in the extreme cold of space. Despite the eventual proximity of the telescope to the center of our solar system, Webb’s instruments must be able to operate at around minus 387 degrees Fahrenheit.
NASA’s Webb telescope gets freezing summertime lodging in Houston during its 100-day cryogenic testing. Credit: NASA/Chris Gunn
What’s Been Happening
The cryogenic test got under way in mid-July at Johnson Space Center inside Chamber A, the same chamber in which NASA tested the Apollo Lunar Module in the 1960s. Leading up to this crucial milestone, Harris experts developed and installed optical test equipment for the cryogenic testing of a two-segment mirror—part of a “practice model” known as Pathfinder—two years ago. Our engineers also integrated all 18 segments of the actual 22-foot diameter, primary Webb telescope mirror, and they designed and installed the cryogenic test equipment, including a simulator to mimic the temperature effect of the sun shield since the actual shield is the size of a tennis court—too big to fit into the chamber.
Harris engineers clean a Webb telescope test mirror segment with carbon dioxide "snow." Credit: NASA/Chris Gunn
It took approximately 10 days for vacuum pumps to remove nearly 100 percent of the air in chamber. A plumbing system filled with liquid nitrogen and cold gaseous helium chilled the instrument to the frigid temperatures of space. When temperatures were steady, our mirrors steered light to the telescope’s science instrument detectors to simulate the light that the telescope will see when deployed. Our folks monitored the temperature sensors, specialized cameras, and other optical equipment to check the alignment and imaging performance of the telescope.
Harris technician Eric Zoller checks the helium shroud in Chamber A at NASA's Johnson Space Center on July 12, 2017. Credit: NASA/Chris Gunn
Vibration and acoustic testing was performed to make sure that the telescope can withstand the stresses of the rocket launch. And because sensitive measurements like those taken during this test can be impacted simply by people walking into the building where the chamber is located, we also built the structure that held and isolated the telescope to protect it from this type of external vibration.
It takes a special bunch of folks with some very special skills to do all of this. And I’m especially proud of the way our team and our NASA partners stepped up to the plate during Hurricane Harvey to keep the test on track and the facility and its valuable contents safe from harm. They even volunteered in the neighborhoods surrounding John Space Center, distributing food and water and assisting in cleanup efforts.
What Happens Next
NASA reports that all of the rigorous tests of the telescope and the spacecraft to date show the mission is meeting its required performance levels. Now, with the completion of cryogenic testing, our team will help prepare the telescope for shipping to Northrop Grumman Aerospace Systems in California, where the shield that will protect the telescope from the sun will be attached and the spacecraft prepared for launch. Test reports and analysis will continue into 2018.
Launch is targeted for 2019, and once on its way, the telescope will take another month to reach its orbit. Six months after launch, checkout should be complete, and official science operations will begin. So what will we discover when Webb points its powerful spectrographic instruments towards the heavens?
I like what Pablo Pérez-González, an astrophysics professor and one of the co-investigators for Webb’s proposed observations, said in a recent NASA press release: "When you build an observatory with unprecedented capabilities, most probably the most interesting results will not be those that you can expect or predict, but those that no one can imagine."
And I share the excitement of our Harris Webb telescope team and scientists around the world as we, like the crew of the starship Enterprise, “go boldly go where no one has gone before.”
Webb will provide new insight into sections of space like the Hubble Ultra Deep Field, a snapshot of about 10,000 galaxies in a tiny patch of sky, taken by NASA’s Hubble Space Telescope. Credit: NASA, European Space Agency, S. Beckwith (STScI), the Hubble Ultra Deep Field Team
Click here to learn more about what’s next for the Webb telescope. Find out more about Harris’ universe exploration solutions at https://www.harris.com/what-we-do/universe-exploration.