Space: NASA turns on James Webb Space Telescope’s high-gain antenna

NASA has turned on the high-gain antenna on the James Webb Space Telescope, allowing the $10 billion observatory to send images and data back to Earth.

James Webb is the most complex space telescope ever built, and was launched in late December last year as the successor to the Hubble observatory.

Among the telescope’s goals will be surveying potentially habitable exoplanets and some of the most distant and oldest objects in the observable universe.

Until now, communications with the telescope had all been via its medium-gain antenna, using the microwave ‘S-band’ of frequencies between 2–4 GHz.

The high-gain antenna, which operates instead in the ‘Ka-band’ (26.5–40 GHz), will allow a higher downlink rate via NASA’s Deep Space Network, the agency said.

This network sports three ground stations in California, Canberra and Madrid, meaning that one location will also be visible to Webb as the Earth turns.

The Ka-band has three data transfer speeds to select from, with the default being the highest, which operates at 3.5 megabytes per second. 

For comparison, the average download speed on a 4G mobile phone connection is around 1–1.25 megabytes per second.

The two slower speeds, meanwhile, can be used to compensate for bad weather at the ground station that might produce interference.

When the telescope begins observations in mid-summer this year the high-gain antenna will transfer at least 28.6 Gigabytes of science data to Earth twice daily.

NASA has turned on the high-gain antenna on the James Webb Space Telescope (pictured), allowing the $10 billion observatory to send images and data back to Earth

Until now, communications with the telescope had all been via its medium-gain antenna, using the microwave 'S-band' of frequencies between 2–4 GHz. The high-gain antenna, which operates instead in the 'Ka-band' (26.5–40 GHz), will allow a higher downlink rate via NASA's Deep Space Network, the agency said

Until now, communications with the telescope had all been via its medium-gain antenna, using the microwave ‘S-band’ of frequencies between 2–4 GHz. The high-gain antenna, which operates instead in the ‘Ka-band’ (26.5–40 GHz), will allow a higher downlink rate via NASA’s Deep Space Network, the agency said

The Deep Space Network sports three ground stations in California, Canberra and Madrid, meaning that one location will also be visible to Webb as the Earth turns. Pictured: the 70 m antenna at the Goldstone Deep Space Communications Complex, California

The Deep Space Network sports three ground stations in California, Canberra and Madrid, meaning that one location will also be visible to Webb as the Earth turns. Pictured: the 70 m antenna at the Goldstone Deep Space Communications Complex, California

James Webb (depicted) — the most complex space telescope ever built — was launched in late December last year and is intended as the successor to the Hubble observatory

James Webb (depicted) — the most complex space telescope ever built — was launched in late December last year and is intended as the successor to the Hubble observatory

NASA’s $10 billion James Webb space telescope 

Operator: NASA 

Launched: December 25, 2021

Full operation begins: Summer 2022

Location: Sun–Earth L2 point 

Orbit type: Halo orbit 

Mission duration: 20 years (expected)

Telescope diameter: 21 feet (6.5 m)

Focal length: 431 feet (131.4 m)

Wavelengths: 0.6–28.3 μm

The high-gain dish was released on 26 December, one day after launch, but well before the craft’s arrival last week at the gravitationally stable ‘Lagrange point’ where it has since ‘parked’.

The antenna assembly is located on the underside of the telescope, being attached to the spacecraft bus which houses the telescope’s power, altitude control and communications systems. 

‘It has been about a month since launch, and it has been an unbelievable ride. I am so filled with pride for our team,’ said James Webb Space Telescope project manager project manager and engineer Bill Ochs, of NASA’s Goddard Space Flight Center.

‘The perfection of the deployment execution and the subsequent activities reflects directly on how hard everyone worked and the diligence and sacrifice it took on the part so many people.

‘We are now ready to align mirrors and commission instruments and have already proven that all the hardware associated with the optics (including 132 actuators) is working beautifully.

‘By the time we get to instrument commissioning, we are going to have one hell of a telescope.

‘Finally, our ops team and ground system have done a fantastic job of executing the commissioning timeline, and all those rehearsals have paid off.’

As Mr Ochs noted, the next step in getting the James Webb Space Telescope ready for scientific observations is to align each of the 18 primary mirror segments to ensure the telescope produces sharp, focused images.

To do this, NASA will be pointing the telescope at HD 84406 — a sun-like, type G star that lies some 260 light-years-away in the constellation of Ursa Major.

While this star is really too bright for James Webb to study properly, it is perfect for aligning its mirrors.

Among the telescope's goals will be surveying potentially habitable exoplanets and some of the most distant and oldest objects in the observable universe

Among the telescope’s goals will be surveying potentially habitable exoplanets and some of the most distant and oldest objects in the observable universe

The next step in getting the James Webb Space Telescope ready for scientific observations is to align each of the 18 primary mirror segments to ensure the telescope produces sharp, focused images. Depicted: the size of James Webb's primary mirrors vs that of Hubble

The next step in getting the James Webb Space Telescope ready for scientific observations is to align each of the 18 primary mirror segments to ensure the telescope produces sharp, focused images. Depicted: the size of James Webb’s primary mirrors vs that of Hubble

Engineers will take 18 separate, out-of-focus images of HD 84406 using each of the mirrors, from which a computer will determine exactly how each must be oriented to bring the telescope into focus.

Each mirror’s direction can be adjusted in the very tiniest of increments — each equal to a ten-thousandth of the width of a human hair.

According to NASA, the initial alignment process is expected to take several months to complete. When the telescope is up and running, the mirrors will also need to be checked and, if necessary, realigned every few days. 

To align James Webb's mirrors, NASA will be pointing the telescope at HD 84406 — a sun-like, type G star that lies some 260 light-years-away in the constellation of Ursa Major. Engineers will take 18 separate, out-of-focus images of HD 84406 using each of the mirrors, from which a computer will determine exactly how each must be oriented to bring the telescope into focus

To align James Webb’s mirrors, NASA will be pointing the telescope at HD 84406 — a sun-like, type G star that lies some 260 light-years-away in the constellation of Ursa Major. Engineers will take 18 separate, out-of-focus images of HD 84406 using each of the mirrors, from which a computer will determine exactly how each must be oriented to bring the telescope into focus

JAMES WEBB SPACE TELESCOPE: THE NEXT BIG ORBITAL OBSERVATORY DEPLOYED TO SEARCH FOR ALIEN LIFE 

Primarily an infrared telescope, it will have a wider spectrum view than Hubble and operate further out from the Earth, in a solar orbit, rather than an Earth orbit. 

Research by Ohio State University claims that within five years of it coming online, James Webb will have found signs of alien life on a distant world.

Graduate student Caprice Phillips calculated that it could feasibly detect ammonia created by living creatures around gas dwarf planets after just a few orbits. 

The James Webb telescope has been described as a ‘time machine’ that could help unravel the secrets of our universe.

The telescope will be used to look back to the first galaxies born in the early universe more than 13.5 billion years ago.

It will also observe the sources of stars, exoplanets, and even the moons and planets of our solar system.

The James Webb Telescope and most of its instruments have an operating temperature of roughly 40 Kelvin.

This is about minus 387 Fahrenheit (minus 233 Celsius). 

Officials from the space agencies responsible for the telescope say the cost may exceed the $8 billion (£5.6 billion) program cap set by Congress.

NASA has already poured $7 billion (£5 billion) into the telescope since it was first proposed as a replacement for the long-running Hubble space telescope.

When it is launched in 2021, it will be the world’s biggest and most powerful telescope, capable of peering back 200 million years after the Big Bang.

James Webb is designed to last for five years but NASA hopes it will operate for a decade or more, although due to its distance from Earth it can’t be easily repaired.

It is 66 ft by 46 ft and will operate at the Sun-Earth Lagrange point about 930,000 miles from the Earth – almost four times further out than the moon. 

The telescope is set to launch on a European workhorse Ariane-5 rocket at the end of October 2021, with the first observations expected in 2022.

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