Nautilus: A Revolutionary Space Telescope
Nautilus is a revolutionary space telescope concept that builds on a novel technology – engineered material diffractive-transmissive optical elements – to overcome the greatest limitations of space telescopes: non-scalable primary mirrors. By providing large but ultra-light telescope apertures, the Nautilus technology will enable the launch of a large fleet of identical telescopes. With a light-collecting power equivalent to a 50m diameter mirror Nautilus will be capable of surveying thousands of earth-sized habitable zone planets for atmospheric signatures of life.
The Search for Life in the Galaxy
Over the past two billion years life has profoundly changed the atmosphere of our planet: the abundance of the free molecular oxygen and ozone – both highly reactive gases – along with water vapor and methane represent a yet unique atmospheric composition. The combined presence of these gases, atmospheric biosignatures, in our planet’s atmosphere is a tracer of life that could be detected remotely, even over galactic distances. But identifying the spectral fingerprints of these atmospheric components in the light reflected by or transmitted through the atmospheres of earth-like planets requires very large telescopes. Even though NASA’s Kepler mission has discovered over 4,000 planets, no existing or planned space telescope has large enough diameter to search for life in their atmospheres.
Finding and correctly interpreting observations of extraterrestrial life is going to be very difficult and a large sample of planetary atmospheres with high-quality that can be compared is likely to be essential for robust results.
Our Nautilus team embarked on a challenge to build a telescope capable of studying a thousand earth-like planets. Our study shows that a telescope with a light-gathering power equivalent to a 50m telescope is required to reach this goal.
A New Way to Collect Starlight
Since the 1970s the complexity and, approximately, the speed of integrated electric circuits have increased by over 5 million fold, transforming most aspects of our life. However, the size of astronomical telescopes has changed much more modestly: the 2.4m Hubble Space Telescope’s primary mirror (designed in the mid seventies and launched in 1990) was only superseded by the Herschel Space Observatory’s 3.6m mirror in 2009, almost three decades later. The next major step will be the launch of the James Webb Space Telescope, with its 6.5m segmented aperture in 2019.
The evolution from HST to JWST represents a 7-fold increase in light collecting power over about five decades, demonstrating how extremely difficult it is to scale the astronomical mirrors larger. In fact, most of the increases in mirror size are due to increased computational processing speeds: segmented mirrors can be aligned and controlled with a high enough cadence and precision to allow them to form a single optical surface (Keck, JWST), while in other large telescopes the surface of large, but thin monolithic mirrors is correct by computer-driven actuators.
Over the past decades astrophysics has been limited by our ability to collect starlight with our telescopes: any technology that enables breaking away from the difficult-to-scale-in-size primary mirrors is set to transform astronomy. Large-scale ultralight-weight optical elements offer such an alternative to primary mirrors.
Our Nautilus Team has developed a new technology, multi-order diffractive engineered lenses (MODE lenses), that provide low-weight, replicable optical elements that can collect light. We have shown that MODE lenses can be fabricated via optical free-form fabrication, which are readily scalable to large diameters. Diffractive optical elements, like the MODE lenses, have been successfully replicated via optical molding, enabling cost-effective and relatively fast production of large-scale optical elements.
We are grateful for the the support of the Gordon and Betty Moore Foundation to further develop the MODE technology and MODE lens-based telescopes.
The Impact of the Nautilus Technology
The goal of our Nautilus team is to change the paradigm of how space telescopes are designed, built, and launched. It will not only transform NASA’s astrophysics missions, but will greatly expand commercial and government satellite technology capabilities.
Why Nautilus?
We named our telescope Nautilus after the revolutionary fictional submarine of Jules Verne (itself named after the first truly operational submarine). Since the publication of the Twenty Thousand Leagues under the Sea in 1870 the Nautilus name has been synonymous with visionary nautical and aeronautical projects, from the ship of Fernando Villaamil that circumnavigated the globe through the Nautilus submarine that served on Arctic expedition in 1931 and the USS Nautilus, the first nuclear submarine, to the Exploration Vessel Nautilus.
Like these projects, our Nautilus Space Telescope builds on a revolutionary new technology to achieve the ambitious goal of exploring the depths of the Universe and other Earth-like planets in the Galaxy.
