Future Space Telescopes Could be 100 Meters Across, Constructed in Space, and Then Bent Into a Precise Shape
It is an exciting time for astronomers and cosmologists. Since the James Webb Space Telescope (JWST), astronomers have been treated to the most vivid and detailed images of the Universe ever taken. Webb‘s powerful infrared imagers, spectrometers, and coronographs will allow for even more in the near future, including everything from surveys of the early Universe to direct imaging studies of exoplanets. Moreover, several next-generation telescopes will become operational in the coming years with 30-meter (~98.5 feet) primary mirrors, adaptive optics, spectrometers, and coronographs.
Even with these impressive instruments, astronomers and cosmologists look forward to an era when even more sophisticated and powerful telescopes are available. For example, Zachary Cordero
of the Massachusetts Institute of Technology (MIT) recently proposed a telescope with a 100-meter (328-foot) primary mirror that would be autonomously constructed in space and bent into shape by electrostatic actuators. His proposal was one of several concepts selected this year by the NASA Innovative Advanced Concepts (NIAC) program for Phase I development.
Corder is the Boeing Career Development Professor in Aeronautics and Astronautics at MIT and a member of the Aerospace Materials and Structures Lab (AMSL) and Small Satellite Center. His research integrates his expertise in processing science, mechanics, and design to develop novel materials and structures for emerging aerospace applications. His proposal is the result of a collaboration with Prof. Jeffrey Lang (from MIT’s Electronics and the Microsystems Technology Laboratories) and a team of three students with the AMSL, including Ph.D. student Harsh Girishbhai Bhundiya.
Their proposed telescope addresses a key issue with space telescopes and other large payloads that are packaged for launch and then deployed in orbit. In short, size and surface precision tradeoffs limit the diameter of deployable space telescopes to the 10s of meters. Consider the recently-launched James Webb Space Telescope (JWST), the largest and most powerful telescope ever sent to space. To fit into its payload fairing (atop an Ariane 5 rocket), the telescope was designed so that it could be folded into a more compact form.
This included its primary mirror, secondary mirror, and sunshield, which all unfolded once the space telescope was in orbit. Meanwhile, the primary mirror (the most complex and powerful ever deployed) measures 6.5 meters (21 feet) in diameter. Its successor, the Large UV/Optical/IR Surveyor (LUVOIR), will have a similar folding assembly and a primary mirror measuring 8 to 15 meters (26.5 to 49 feet) in diameter – depending on the selected design (LUVOIR-A or -B). As Bhundiya explained to Universe Today via email:
“Today, most spacecraft antennas are deployed in orbit (e.g., Northrop Grumman’s Astromesh antenna) and have been optimized to achieve high performance and gain. However, they have limitations: 1) They are passive deployable systems. I.e. once you deploy them you cannot adaptively change the shape of the antenna. 2) They become difficult to slew as their size increases. 3) They exhibit a tradeoff between diameter and precision. I.e. their precision decreases as their size increases, which is a challenge for achieving astronomy and sensing applications that require both large diameters and high precision (e.g. JWST).”
While many in-space construction methods have been proposed to overcome these limitations, detailed analyses of their performance for building precision structures (like large-diameter reflectors) are lacking. For the sake of their proposal, Cordero and his colleagues conducted a quantitative, system-level comparison of materials and processes for in-space manufacturing. Ultimately, they determined that this limitation could be overcome using advanced materials and a novel in-space manufacturing method called Bend-Forming.
This technique, invented by researchers at the AMSL and described in a recent paper co-authored by Bhundiya and Cordero, relies on a combination of Computer Numerical Control (CNC) deformation processing and hierarchical high-performance materials. As Harsh explained it:
“Bend-Forming is a process for fabricating 3D wireframe structures from metal wire feedstock. It works by bending a single strand of wire at specific nodes and with specific angles, and adding joints to the nodes to make a stiff structure. So to fabricate a given structure, you convert it into bending instructions which can be implemented on a machine like a CNC wire bender to fabricate it from a single strand of feedstock. The key application of Bend-Forming is to manufacture the support structure for a large antenna on orbit. The process is well-suited for this application because it is low-power, can fabricate structures with high compaction ratios, and has essentially no size limit.”
In contrast to other in-space assembly and manufacturing approaches, Bend-Forming is low-power and is uniquely enabled by the extremely low-temperature environment of space. In addition, this technique enables smart structures that leverage multifunctional materials to achieve new combinations of size, mass, stiffness, and precision. Additionally, the resulting smart structures leverage multifunctional materials to achieve unprecedented combinations of size, mass, stiffness, and precision, breaking the design paradigms that limit conventional truss or tension-aligned space structures.
In addition to their native precision, Large Bend-Formed structures can use their electrostatic actuators to contour a reflector surface with sub-millimeter precision. This, said Harsh, will increase the precision of their fabricated antenna in orbit:
“The method of active control is called electrostatic actuation and uses forces generated by electrostatic attraction to precisely shape a metallic mesh into a curved shape which acts as the antenna reflector. We do this by applying a voltage between the mesh and a ‘command surface’ which consists of the Bend-Formed support structure and deployable electrodes. By adjusting this voltage, we can precisely shape the reflector surface and achieve a high-gain, parabolic antenna.”
Harsh and his colleagues deduce that this technique will allow for a deployable mirror measuring more than 100 meters (328 ft) in diameter that could achieve a surface precision of 100 m/m and a specific area of more than 10 m2/kg. This capability would surpass existing microwave radiometry technology and could lead to significant improvements in storm forecasts and an improved understanding of atmospheric processes like the hydrologic cycle. This would have significant implications for Earth Observation and exoplanet studies.
The team recently demonstrated a 1-meter (3.3 ft) prototype of an electrostatically-actuated reflector with a Bend-Formed support structure at the 2023 American Institute of Aeronautics and Astronautics (AIAA) SciTech Conference, which ran from January 23rd to 27th in National Harbor, Maryland. With this Phase I NIAC grant, the team plans to mature the technology with the ultimate aim of creating a microwave radiometry reflector.
Looking ahead, the team plans to investigate how Bend-Forming can be used in geostationary orbit (GEO) to create a microwave radiometry reflector with a 15km (9.3 mi) field of view, a ground resolution of 35km (21.75 mi) and a proposed frequency span of 50 to 56 GHz – the super-high and extremely-high frequent range (SHF/EHF). This will enable the telescope to retrieve temperature profiles from exoplanet atmospheres, a key characteristic allowing astrobiologists to measure habitability.
“Our goal with the NIAC now is to work towards implementing our technology of Bend-Forming and electrostatic actuation in space,” said Harsh. “We envision fabricating 100-m diameter antennas in geostationary orbit with have Bend-Formed support structure and electrostatically-actuated reflector surfaces. These antennas will enable a new generation of spacecraft with increased sensing, communication, and power capabilities.”
Further Reading: NASA
James Webb spots swirling, gritty clouds on remote planet
Researchers observing with NASA’s James Webb Space Telescope have pinpointed silicate cloud features in a distant planet’s atmosphere. The atmosphere is constantly rising, mixing, and moving during its 22-hour day, bringing hotter material up and pushing colder material down.
The resulting brightness changes are so dramatic that it is the most variable planetary-mass object known to date. The team, led by Brittany Miles of the University of Arizona, also made extraordinarily clear detections of water, methane and carbon monoxide with Webb’s data, and found evidence of carbon dioxide. This is the largest number of molecules ever identified all at once on a planet outside our solar system.
Cataloged as VHS 1256 b, the planet is about 40 light-years away and orbits not one, but two stars over a 10,000-year period. “VHS 1256 b is about four times farther from its stars than Pluto is from our sun, which makes it a great target for Webb,” Miles said. “That means the planet’s light is not mixed with light from its stars.”
Higher up in its atmosphere, where the silicate clouds are churning, temperatures reach a scorching 1,500 degrees Fahrenheit (815 degrees Celsius).
Within those clouds, Webb detected both larger and smaller silicate dust grains, which are shown on a spectrum. “The finer silicate grains in its atmosphere may be more like tiny particles in smoke,” noted co-author Beth Biller of the University of Edinburgh in Scotland. “The larger grains might be more like very hot, very small sand particles.”
VHS 1256 b has low gravity compared to more massive brown dwarfs, which means that its silicate clouds can appear and remain higher in its atmosphere where Webb can detect them. Another reason its skies are so turbulent is the planet’s age. In astronomical terms, it’s quite young. Only 150 million years have passed since it formed—and it will continue to change and cool over billions of years.
In many ways, the team considers these findings to be the first “coins” pulled out of a spectrum that researchers view as a treasure chest of data. In many ways, they’ve only begun identifying its contents. “We’ve identified silicates, but better understanding which grain sizes and shapes match specific types of clouds is going to take a lot of additional work,” Miles said. “This is not the final word on this planet—it is the beginning of a large-scale modeling effort to fit Webb’s complex data.”
Although all of the features the team observed have been spotted on other planets elsewhere in the Milky Way by other telescopes, other research teams typically identified only one at a time. “No other telescope has identified so many features at once for a single target,” said co-author Andrew Skemer of the University of California, Santa Cruz. “We’re seeing a lot of molecules in a single spectrum from Webb that detail the planet’s dynamic cloud and weather systems.”
The team came to these conclusions by analyzing data known as spectra gathered by two instruments aboard Webb, the Near-Infrared Spectrograph (NIRSpec) and the Mid-Infrared Instrument (MIRI). Since the planet orbits at such a great distance from its stars, the researchers were able to observe it directly, rather than using the transit technique or a coronagraph to take this data.
There will be plenty more to learn about VHS 1256 b in the months and years to come as this team—and others—continue to sift through Webb’s high-resolution infrared data. “There’s a huge return on a very modest amount of telescope time,” Biller added. “With only a few hours of observations, we have what feels like unending potential for additional discoveries.”
What might become of this planet billions of years from now? Since it’s so far from its stars, it will become colder over time, and its skies may transition from cloudy to clear.
The researchers observed VHS 1256 b as part of Webb’s Early Release Science program, which is designed to help transform the astronomical community’s ability to characterize planets and the disks where they form.
The team’s paper, entitled “The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b,” will be published in The Astrophysical Journal Letters.
The work is currently published on the arXiv preprint server.
Brittany E. Miles et al, The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b, arXiv (2022). DOI: 10.48550/arxiv.2209.00620
James Webb spots swirling, gritty clouds on remote planet (2023, March 22)
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Parade of planets: Jupiter, Mercury, Venus, Uranus and Mars alignment
Sky-gazers will be treated to a parade of planets near the end of month when Jupiter, Mercury, Venus, Uranus and Mars will appear together in the night sky.
On March 28, a large planetary alignment will take place when the five planets appear just after sunset, all within a 50-degree sector of the sky, according to sky tracking site Starwalk.
Jupiter and Mercury will appear near the horizon, in the constellation Pisces, while Venus will be visible higher in the sky on the constellation Aries, the sky-tracking site noted.
Next, Uranus will line up nearby but a pair of binoculars may be required to get a glimpse of the planet. Finally, Mars will appear higher in the sky, near the moon, to complete the five-planet alignment.
“Although March 28 is the best day for observation, the alignment will be visible several days before and after that date,” the website explained.
If the weather isn’t in your favour next week, there will be other opportunities to catch a planetary alignment this year, including another five-planet alignment on June 17. Mercury, Uranus, Jupiter, Neptune, and Saturn will be on parade that evening.
'Astronomical lightshow' – Gazette
Next year, 2024, is Solar Eclipse Year.
On April 8, 2024, a total solar eclipse will be visible from the south Pacific Ocean, northern Mexico, across the U.S. and through the Atlantic provinces of Canada.
More importantly, the total solar eclipse will be visible from southwestern Newfoundland, in the areas of Stephenville and across central Newfoundland through Terra Nova Park and Gander.
A partial eclipse will be visible across the province, with St. John’s and Corner Brook just outside the range of a total eclipse, an 80 per cent eclipse in Labrador City and a 70 per cent eclipse in Nain.
The 2024 solar eclipse will be the first eclipse crossing the province since 1970 and the only one until 2079.
For many, this is a once-in-a-lifetime event to see a total solar eclipse in Newfoundland and Labrador.
“Solar eclipses are special events in many cultures and have allowed scientists to make great discoveries.”
We are fortunate to even be able to observe a solar eclipse.
The Earth is the only place in our solar system where there is a moon that is about the same size in the sky (0.5 degree) as the sun.
Solar eclipses are special events in many cultures and have allowed scientists to make great discoveries.
When the moon passes in front of the sun, most of the light is blocked and we can see the sun’s corona (more about the corona below).
A note: make sure to wear appropriate eye protection during an eclipse to look at the sun.
The late Dr. Jay Pasachoff, an American astronomer, was so inspired by solar eclipses that he chased them around the world to experience more than 70 eclipses in about 50 years.
In a New York Times 2010 op-ed, he wrote: “There’s also the primal thrill this astronomical lightshow always brings the perfect alignment, in solemn darkness, of the celestial bodies that mean most to us.”
There is the thrill of observing solar eclipses and there is the thrilling science of them, too.
Thanks to solar eclipses, we learn about the sun’s corona, a thin layer of plasma that is just above the sun’s surface.
We normally can’t see it because it is so thin and has such a small density, but the temperature of the corona is about one million degrees Celsius.
It is believed that the corona is related to the sun’s magnetic field and to things like solar flares and mass ejections.
These flares and mass ejections impact the Earth through space weather and the aurorae — phenomena that those of us in the Northern Hemisphere recognize as the Northern Lights.
And it’s not just the sun.
Solar eclipses were important to provide some of the early evidence of Albert Einstein’s Theory of General Relativity.
Einstein predicted that light is bent by the gravity of stars.
So, if we can see stars behind the sun, they will appear to be in a slightly different location in the sky relative to each other than when we see them normally.
In 1919 scientists observed stars behind the sun that became visible during a solar eclipse and found that, indeed, their observations agreed with Einstein’s theory.
Town of Gander a major partner
Solar eclipses are fantastic events that connect humans to nature, celestial bodies and to the universe.
Next year’s celebration is an opportunity to celebrate science, nature and humanity.
Thanks to the enthusiasm and excitement of its staff and council, Prof. Svetlana Barkanova, Department of Physics, Grenfell Campus, and I are partnering with the Town of Gander to host a solar eclipse viewing party on April 8, 2024, and a science festival in the days before the eclipse.
The town is excited to be a major partner bringing people from across Newfoundland and Labrador to learn, discover and experience a total solar eclipse together.
The town has pledged to develop a budget to assist with the costs of this unique science festival, along with providing facilities, viewing sites and in-kind assistance.
The event is being planned in collaboration with a continuing science and community outreach program led by Prof. Barkanova and her team.
They deliver a large-scale scientific and cultural outreach program for youth in our province, especially rural youth, girls and Indigenous students, and is currently developing in-person and online seminars and workshops leading up to the solar eclipse.
“It is an ideal chance for us at Memorial to do what we do best — share what is great about our fields.”
This is a call to faculty, students and staff at Memorial University across all campuses to join in the celebration and help it grow and expand.
Not only will we have the opportunity to experience an amazing celestial event, it is a chance to come together in central Newfoundland and share the stories of what we do at Memorial from how we understand the sun and moon in astrophysics, in cultures, in literatures, in humanities and so on.
This is a call to action for your involvement; more participating colleagues means more public talks, Science on Tap events, outreach in schools and more.
It is an ideal chance for us at Memorial to do what we do best — share what is great about our fields and do so around this rare event in Newfoundland and Labrador.
Come join in for Solar Eclipse Year 2024 in Gander. Contact me via email.
Co-authored by Dr. Svetlana Barkanova, Department of Physics, Grenfell Campus, and Brian Williams, tourism development officer, Town of Gander.
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