Last year saw a great many exciting developments in space exploration.
Starting with our own solar system, we discovered that Venus (our nearest planetary neighbour, depending on the relative orbits of Venus and Earth around the Sun at a given time) shows some evidence that it may have once had oceans that may have supported life.
Our next planetary neighbour, Mars, has been the subject of significant exploration for many years, including by many robotic probes that have landed on its surface. Each exploration yields new insights, with last year’s discoveries including an ice sheet over 170 metres thick.
New evidence for oceans on other planets, dwarf planets and moons also came to light last year, including suggestions of an ocean on Pluto.
September 2016 also saw the launch of NASA’s first asteroid sampling mission, called the OSIRIS-Rex spacecraft. The craft will study the asteroid Bennu, and return a sample to Earth in 2023.
Moving even further beyond our solar system to the hunt for exoplanets (planets orbiting other stars), in May 2016, an announcement was made by astronomers who are using NASA’s Kepler space telescope, that a further 1284 planets had been found, bringing the number of confirmed new exoplanets to over 2000, and the number of identified potential planets to over 4000.
These discoveries are the result of great human ingenuity, including designing, building and deploying of space craft, as well as the use of innovative detection and data analysis techniques. While many discoveries are made using a variety of earth-based and space-based sensors and devices, space telescopes play a very important role in our current knowledge of our own solar system, our galaxy and the Universe.
Telescopes such as the legendary Hubble Space Telescope (capturing images in visible light), the Spitzer Space Telescope (with infrared vision), the Kepler telescope and the yet-to-be-launched James Webb Space Telescope with its 18-segment primary mirror that will unfold once launched, each drive our knowledge of the Universe further.
This article looks at some patents behind a few of the technologies related to space telescopes, including optics, craft design, sensors and signal processing. The patents discussed below are not necessarily covering technologies currently being used in deployed telescopes, and the patents are not analysed in detail from a technical or legal position, but have been selected simply to provide an indication of the range of technologies developed for such application.
One particularly interesting area of application is in relation to segmented mirrors. A segmented mirror provides a primary mirror made of multiple sub-mirror elements. Such a mirror is part of the design of the James Webb Space Telescope. In this design, 18 hexagonal sub-mirror elements together form a 6.5 metre-wide primary mirror. The design allows the mirror to be folded for launch and then to unfold once in space. The 18 sub-mirror elements may be individually aligned to produce the best optical performance for the mirror.
A number of the patents and patent applications referred to below are directed to aspects of segmented-mirror design.
1. Autonomously Assembled Space Telescope US20050088734 (The Boeing Company)
This patent application was filed on 28 October 2003 and is directed to a space telescope having a primary mirror comprising a plurality of modular, segmented mirrors. The segments of the primary mirror are supported by a backing structure which itself comprises a plurality of interlocking mirror backing structure elements.
The invention provides a system for forming a large mirror in space, by assembling multiple segments, once launched. These segments can be launched in separate launch vehicles, thus enabling a completed mirror to be larger than one that could be launched in a single launch.
2. Achromatic shearing phase sensor for generating images indicative of measure(s) of alignment between segments of a segmented telescope’s mirrors US7106457 (NASA)
This granted patent in the name of NASA, provides a sensor for assisting in the alignment of the segments of a multi-segmented mirror. As will be appreciated, for a multi-segment mirror to perform optimally, the different segments must be aligned such that they operate as a single contiguous surface. When properly aligned, each segment produces an image at the same place in all three spatial dimensions. The alignment of the segments in the x and y dimensions perpendicular to the direction of propagation is achieved by direct measurement of the irradiance from a particular segment. The third dimension, the z-axis, involves measurement of the phase of a wavefront.
The invention of this patent provides an achromatic shearing phase sensor for use in alignment of a segmented telescope’s mirrors.
3. Apparatus and method for a light direction sensor US7924415 (NASA)
This granted patent filed on 19 February 2009, is directed to a light direction sensor for determining the direction of a light source. Knowledge of the precise direction of a light source such as the Sun or Moon, can be used for various applications including spacecraft navigation.
The sensor comprises a Cartesian mask, an array image sensor and an image processing algorithm.
4. Hybrid architecture wavefront sensing and control system and method US8044332 (NASA)
This granted patent is directed to an optical system for providing both fine guidance sensing and wavefront sensing in a single instrument. In some applications, the system can generate instructions to adjust the position of at least one mirror comprising the optical assembly of the telescope in accordance with the sensing operations.
5. Device for protecting optical and/or electronic apparatuses, space telescope comprising said device, and device for removably occluding an aperture US8064154 (Thales Alenia Space Italia SpA)
This granted patent is directed to a protective device to protect sensitive optical and/or electronic apparatus mounted to a spacecraft such as a space telescope.
The protective device is mounted over an aperture through which the optical and/or electronic apparatus is accessed. The device comprises a plurality of pairs of elements, each of which can be actuated between a first position and a second position, to provide a closed cover or screen for the aperture when the elements are in the first position, and an open aperture when the elements are in the second position.
This provides protection for the sensitive instrumentation which can be easily damaged if struck by small objects or particles in space.
6. NanoStructured additives to high-performance polymers for use in radiation shielding, protection against atomic oxygen and in structural applications US20130161564 (International Scientific Technologies, Inc.)
This patent application, filed on 22 December 2011, is directed to nanostructured additives for improving the shielding capabilities of a high-performance polymer to which the additive is added, without significantly affecting the thermal and mechanical properties of the polymer.
The environment in space can be extremely harsh to craft and objects, with cosmic radiation being a significant danger. Sensitive electronics and instruments can be damaged when exposed to certain types of radiation, and there is a need to protect against the adverse effects of radiation. The invention is concerned with general Galactic Cosmic Radiation, Solar Energetic Particles, as well as secondary particulate and electromagnetic radiation resulting from nuclear reactions from power sources within the shield.
7. Occulter for exoplanet exploration US8480241 (Lockheed Martin Corporation)
This patent is directed to a space based occulter to block out starlight emitted from a star, to facilitate the detection of planets orbiting that star. The occulter comprises a base portion and a blanket section extending radially from the base portion. A plurality of starlight blocking petals is attached to the base portion and the blanket section, with each of the panels being hingedly connected to an adjacent petal.
8. Deployable telescopic shade US7557995 (Itt Manufacturing Enterprises, Inc.)
The image quality of a telescope can be adversely affected by the presence of stray light – ie light not produced by the object being imaged. This granted patent is directed to an imaging apparatus comprising a telescope and a shade. The shade comprises a plurality of pivotable panels which act to provide a collapsed state of the shade to block light from reaching the telescope, and a deployed state of the shade to expose the telescope to light.
The selected patents are but a small sample of patents representing this very active area of development.
For more information on the achievements of space exploration and research in 2016 and news on upcoming developments, see NASA’s website here.
NOTE – images from respective patent publications on Google Patents