A new, thin-lensed telescope design could far surpass JWST | 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 seemingly want more powerful telescopes than exist as we speak.

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 type of space telescope that would acquire 100 occasions extra mild than the James Webb Space Telescope, the most important space telescope ever constructed.

Virtually all space telescopes, together with Hubble and Webb, acquire mild utilizing mirrors. Our proposed telescope, the Nautilus Space Observatory, would change 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 might be potential 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 large space telescopes that acquire big 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 in regards to 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 bold telescope tasks are all the time costly, laborious and produce a single highly effective – however very specialised – observatory.

A brand new type of telescope

In 2016, aerospace large Northrop Grumman invited me and 14 different professors and NASA scientists – all consultants 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, just a few of us got here up with the thought of revisiting an outdated expertise referred to as diffractive lenses.

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

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

Skinny, easy diffractive lenses are notorious for their blurry images, so that they have by no means been utilized in astronomical observatories. However should you may enhance their readability, utilizing diffractive lenses as an alternative 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 fashionable expertise may produce diffractive lenses with higher picture high quality. Fortunate for me, Thomas Milster – one of many world’s main consultants on diffractive lens design – works within the constructing subsequent to mine. We shaped a crew and started working.

Over the next two years, our crew invented a brand new sort of diffractive lens that required new manufacturing applied sciences to etch a posh sample of tiny grooves onto a bit of clear glass or plastic. The precise sample and form of the cuts focuses incoming mild 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 possibly can simply make the lens larger whereas keeping it very thin and lightweight. Larger lenses acquire extra mild, 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 scale. We at the moment are finishing a 10-inch (24-cm) diameter lens that will probably be greater than 10 occasions lighter than a traditional refractive lens can be.

Energy of a diffraction space telescope

This new lens design makes it potential to rethink how a space telescope may be constructed. In 2019, our crew revealed an idea referred to as the Nautilus Space Observatory.

Utilizing the brand new expertise, our crew thinks it’s potential to construct a 29.5-foot (8.5-meter) diameter lens that will 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 thrice lighter than a Webb–model mirror of the same 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 may be made en masse. Second, lens-based telescopes work properly 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 mild and comparatively low cost to supply, it might be potential to place dozens of them into orbit. Our present design is in reality not a single telescope, however a constellation of 35 particular person telescope models.

Every particular person telescope can be an unbiased, extremely delicate observatory in a position to acquire extra mild than Webb. However the true energy of Nautilus would come from turning all the person telescopes towards a single goal.

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

Though the Nautilus House Observatory remains to be a great distance from launch, our crew has made plenty of progress. We now have proven that every one points of the expertise work in small-scale prototypes and at the moment are 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 will probably be able to suggest a revolutionary new space telescope to NASA and, hopefully, be on the best way to exploring a whole bunch 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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