FAQs

What is the James Webb Space Telescope?

Designed and built by NASA in partnership with the Canadian and European Space Agencies, the Webb will be a ‘flagship’ space observatory. An infrared specialist, it will be able to explore the distant Universe and the evolution of planets, stars and galaxies as never before.

Who was James E. Webb?

He was NASA administrator during the height of the space race and instrumental in getting humans to the Moon. He also oversaw the first US interplanetary probe missions. As a tribute to this legacy, the telescope bears his name.

What are the key science goals?

There are more details here but it wouldn’t be too much of a stretch to say: ‘the origins of life, the Universe and everything.’

When will it launch?

The launch window is currently scheduled for March 2021.

How long will the mission last?

The telescope has been designed to last for a minimum of five years of science observations so that it can accomplish its primary mission. It has a goal to carry enough fuel to last for 10 years.

How is the UK contributing?

The construction of Webb is a global enterprise, involving 14 countries, and the UK has been active since its earliest stages of development. Our main contribution has been leading the design and construction of one of the four science instruments, the Mid-infrared Instrument (MIRI), in a partnership with JPL, ESA and a number of European institutes. As well as manufacturing key parts of MIRI in the UK, the ESA-led NIRSPEC instrument has had components built here in the UK. UK companies have won contracts from NASA to build parts of the spacecraft too. Many UK-based researchers will also be looking forward to working with the first data from Webb.

How does it compare to the Hubble Space Telescope?

The two telescopes aren’t directly comparable as they are optimised to observe at different wavelengths of light. Hubble can observe in ultraviolet/optical/near-infrared light whereas Webb is an infrared specialist. The main mirror for Webb, the largest ever flown in space, has five-and-a-half times the collecting area of Hubble, giving it a significant advantage at these wavelengths. Hubble currently lives in low-Earth orbit, Webb will be stationed much further away.

How does it compare to the Spitzer Space Telescope?

Spitzer is another infra-red specialist, now nearing the end of its extended mission as it drifts further from Earth. The large mirror of the Webb allows it to reach greater depths and resolve much finer detail than Spitzer. The Webb also has the capability to perform simultaneous measurements of hundreds of galaxies at the same time, giving it a clear advantage in building up large samples of objects. The primary factor in the end of the Spitzer main mission was that it ran out of coolant for its detectors and in the case of the Webb, it will not be coolant that limits the lifespan of the mission but the propellant required to keep it on station.

Who designed/built/runs it?

Webb has been designed and built by NASA and involving the American, Canadian and European space agencies, companies and organisations. Final integration and testing is being performed at NASA Goddard Flight Centre, and Northrup Grumman. The day-to-day operations of the telescope will be handled via the Space Telescope Science Institute.

Where will it be situated?

During the lifetime of the mission, the Webb will be circling a point on the opposite side of the Earth to the Sun. It will be remote, four times more distant than the Moon, but affords a good view of the sky whilst minimising stray light from the Earth/Moon system.

Where can I find out more?

The NASA/ESA websites have extra material on the Webb for those of you who are keen for more. In the run up to launch we will also be adding new content for general audiences. This will include resources for educators and public engagement specialists as well. Sign up to our various mailing lists if you’d like to be kept up to date when any new content is added.

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