A new, thin-lensed telescope design could far surpass James Webb | Astronomy.com

Astronomers have found greater than 5,000 planets outside of the solar system so far. The grand query is whether or not any of these planets are home to life. To search out the reply, astronomers will possible want more powerful telescopes than exist immediately.

I’m an astronomer who studies astrobiology and planets round distant stars. For the final seven years, I’ve been co-leading a crew that’s growing a brand new form of space telescope that might gather 100 occasions extra gentle than the James Webb Space Telescope, the largest space telescope ever constructed.

Virtually all space telescopes, together with Hubble and Webb, gather gentle utilizing mirrors. Our proposed telescope, the Nautilus Space Observatory, would exchange massive, heavy mirrors with a novel, skinny lens that’s a lot lighter, cheaper and simpler to supply than mirrored telescopes. Due to these variations, it will be attainable to launch many particular person models into orbit and create a strong community of telescopes.

The necessity for bigger telescopes

Exoplanets – planets that orbit stars apart from the Solar – are prime targets within the seek for life. Astronomers want to make use of big space telescopes that gather large quantities of sunshine to study these faint and faraway objects.

Current telescopes can detect exoplanets as small as Earth. Nonetheless, it takes much more sensitivity to start to study concerning the chemical composition of those planets. Even Webb is simply barely highly effective sufficient to look certain exoplanets for clues of life – particularly gases in the atmosphere.

The James Webb House Telescope price greater than US$8 billion and took over 20 years to build. The subsequent flagship telescope will not be anticipated to fly earlier than 2045 and is estimated to cost $11 billion. These formidable telescope initiatives are all the time costly, laborious and produce a single highly effective – however very specialised – observatory.

A brand new form of telescope

In 2016, aerospace big Northrop Grumman invited me and 14 different professors and NASA scientists – all specialists on exoplanets and the seek for extraterrestrial life – to Los Angeles to reply one query: What’s going to exoplanet space telescopes appear to be in 50 years?

In our discussions, we realized {that a} main bottleneck stopping the development of extra highly effective telescopes is the problem of creating bigger mirrors and getting them into orbit. To bypass this bottleneck, a couple of of us got here up with the concept of revisiting an outdated know-how known as diffractive lenses.

Standard lenses use refraction to focus gentle. Refraction is when light changes direction because it passes from one medium to a different – it’s the purpose gentle bends when it enters water. In distinction, diffraction is when gentle bends round corners and obstacles. A cleverly organized sample of steps and angles on a glass floor can type a diffractive lens.

The primary such lenses have been invented by the French scientist Augustin-Jean Fresnel in 1819 to supply light-weight lenses for lighthouses. Immediately, related diffractive lenses will be discovered in lots of small-sized shopper optics – from camera lenses to virtual reality headsets.

Skinny, easy diffractive lenses are notorious for their blurry images, in order that they have by no means been utilized in astronomical observatories. However in the event you may enhance their readability, utilizing diffractive lenses as a substitute of mirrors or refractive lenses would enable a space telescope to be less expensive, lighter and bigger.

A skinny, high-resolution lens

After the assembly, I returned to the College of Arizona and determined to discover whether or not trendy know-how may produce diffractive lenses with higher picture high quality. Fortunate for me, Thomas Milster – one of many world’s main specialists on diffractive lens design – works within the constructing subsequent to mine. We shaped a crew and set to work.

Over the next two years, our crew invented a brand new sort of diffractive lens that required new manufacturing applied sciences to etch a fancy sample of tiny grooves onto a bit of clear glass or plastic. The precise sample and form of the cuts focuses incoming gentle to a single level behind the lens. The brand new design produces a near-perfect quality image, much better than earlier diffractive lenses.

As a result of it’s the floor texture of the lens that does the focusing, not the thickness, you may simply make the lens larger whereas keeping it very thin and lightweight. Larger lenses gather extra gentle, and low weight means cheaper launches to orbit – each nice traits for a space telescope.

In August 2018, our crew produced the primary prototype, a 2-inch (5-centimeter) diameter lens. Over the following 5 years, we additional improved the picture high quality and elevated the dimensions. We are actually finishing a 10-inch (24-cm) diameter lens that might be greater than 10 occasions lighter than a standard refractive lens can be.

Energy of a diffraction space telescope

This new lens design makes it attainable to rethink how a space telescope could be constructed. In 2019, our crew printed an idea known as the Nautilus Space Observatory.

Utilizing the brand new know-how, our crew thinks it’s attainable to construct a 29.5-foot (8.5-meter) diameter lens that might be solely about 0.2 inches (0.5 cm) thick. The lens and assist construction of our new telescope may weigh round 1,100 kilos (500 kilograms). That is greater than 3 times lighter than a Webb–fashion mirror of an identical dimension and can be larger than Webb’s 21-foot (6.5-meter) diameter mirror.

The lenses produce other advantages, too. First, they’re much easier and quicker to fabricate than mirrors and will be made en masse. Second, lens-based telescopes work effectively even when not aligned completely, making these telescopes simpler to assemble and fly in space than mirror-based telescopes, which require extraordinarily exact alignment.

Lastly, since a single Nautilus unit can be gentle and comparatively low-cost to supply, it will be attainable to place dozens of them into orbit. Our present design is in truth not a single telescope, however a constellation of 35 particular person telescope models.

Every particular person telescope can be an impartial, extremely delicate observatory capable of gather extra gentle than Webb. However the actual energy of Nautilus would come from turning all the person telescopes towards a single goal.

By combining information from all of the models, Nautilus’ light-collecting energy would equal a telescope almost 10 occasions bigger than Webb. With this highly effective telescope, astronomers may search tons of of exoplanets for atmospheric gases which will indicate extraterrestrial life.

Though the Nautilus House Observatory remains to be a good distance from launch, our crew has made a variety of progress. Now we have proven that every one points of the know-how work in small-scale prototypes and are actually specializing in constructing a 3.3-foot (1-meter) diameter lens. Our subsequent steps are to ship a small model of the telescope to the sting of space on a high-altitude balloon.

With that, we might be able to suggest a revolutionary new space telescope to NASA and, hopefully, be on the way in which to exploring tons of of worlds for signatures of life.

Daniel Apai, Affiliate Dean for Analysis and Professor of Astronomy and Planetary Sciences, University of Arizona

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