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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Regolith Adherence Characterization, or RAC, is one of 10 science and technology instruments flying on NASA’s next Commercial Lunar Payload Services (CLPS) flight as part of the Blue Ghost Misison-1. Developed by Aegis Aerospace of Webster, Texas, RAC is designed to study how lunar dust reacts to more than a dozen different types of material samples, located on the payload’s wheels. Photo courtesy Firefly Aerospace The Moon may look like barren rock, but it’s actually covered in a layer of gravel, pebbles, and dust collectively known as “lunar regolith.” During the Apollo Moon missions, astronauts learned firsthand that the fine, powdery dust – electromagnetically charged due to constant bombardment by solar and cosmic particles – is extremely abrasive and clings to everything: gloves, boots, vehicles, and mechanical equipment. What challenges does that dust pose to future Artemis-era missions to establish long-term outposts on the lunar surface?
That’s the task of an innovative science instrument called RAC-1 (Regolith Adherence Characterization), one of 10 NASA payloads flying aboard the next delivery for the agency’s CLPS (Commercial Lunar Payload Services) initiative and set to be carried to the surface by Firefly Aerospace’s Blue Ghost 1 lunar lander.
Developed by Aegis Aerospace of Webster, Texas, RAC will expose 15 sample materials – fabrics, paint coatings, optical systems, sensors, solar cells, and more – to the lunar environment to determine how tenaciously the lunar dust sticks to each one. The instrument will measure accumulation rates during landing and subsequent routine lander operations, aiding identification of those materials which best repel or shed dust. The data will help NASA and its industry partners more effectively test, upgrade, and protect spacecraft, spacesuits, habitats, and equipment in preparation for continued exploration of the Moon under the Artemis campaign.
“Lunar regolith is a sticky challenge for long-duration expeditions to the surface,” said Dennis Harris, who manages the RAC payload for NASA’s CLPS initiative at the agency’s Marshall Space Flight Center in Huntsville, Alabama. “Dust gets into gears, sticks to spacesuits, and can block optical properties. RAC will help determine the best materials and fabrics with which to build, delivering more robust, durable hardware, products, and equipment.”
Under the CLPS model, NASA is investing in commercial delivery services to the Moon to enable industry growth and support long-term lunar exploration. As a primary customer for CLPS deliveries, NASA aims to be one of many customers on future flights. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the development of seven of the 10 CLPS payloads carried on Firefly’s Blue Ghost lunar lander.
Learn more about. CLPS and Artemis at:
https://www.nasa.gov/clps
Alise Fisher
Headquarters, Washington
202-358-2546
Alise.m.fisher@nasa.gov
Headquarters, Washington
202-358-2546
Alise.m.fisher@nasa.gov
Corinne Beckinger
Marshall Space Flight Center, Huntsville, Ala.
256-544-0034
corinne.m.beckinger@nasa.gov
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Last Updated Dec 20, 2024 EditorBeth RidgewayContactCorinne M. Beckingercorinne.m.beckinger@nasa.govLocationMarshall Space Flight Center Related Terms
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By NASA
“Trying to do stellar observations from Earth is like trying to do birdwatching from the bottom of a lake.” James B. Odom, Hubble Program Manager 1983-1990.
The third servicing mission to the Hubble Space Telescope, placed in orbit in 1990, occurred during the STS-103 mission in December 1999. During the mission, originally planned for June 2000 but accelerated by six months following unexpected failures of the telescope’s attitude control gyroscopes, the astronauts restored the facility to full functionality. During their eight-day mission that featured the first space shuttle crew to spend Christmas in space, the seven-member U.S. and European crew rendezvoused with and captured Hubble, and four astronauts in rotating teams of two conducted three lengthy and complex spacewalks to service and upgrade the telescope. They redeployed the telescope with greater capabilities than ever before to continue its mission to help scientists unlock the secrets of the universe.
Schematic showing the Hubble Space Telescope’s major components. Workers inspect the Hubble Space Telescope’s 94-inch diameter primary mirror prior to assembly. Astronauts release the Hubble Space Telescope in April 1990 during the STS-31 mission. The discovery after the Hubble Space Telescope’s launch in 1990 that its primary mirror suffered from a flaw called spherical aberration disappointed scientists who could not obtain the sharp images they had expected. But thanks to the Hubble’s built-in feature of on-orbit servicing, NASA devised a plan to correct the telescope’s optics during the first planned repair mission in 1993. A second servicing mission in 1997 upgraded the telescope’s capabilities until the next mission planned for three years later. But after three of the telescope’s six gyroscopes failed in 1997, 1998, and 1999, mission rules dictated a call up mission in case additional gyroscope failures sent Hubble into a safe mode. NASA elected to move up some of the servicing tasks from the third mission, splitting it into missions 3A and 3B, planning to fly 3A in October 1999 on Discovery’s STS-103 mission primarily to replace the failed gyroscopes. Delays to the shuttle fleet resulting from anomalies during the launch of STS-93 in July 1993 slipped STS-103 first into November and ultimately into December. Technical issues with Discovery itself pushed the launch date to mid-December, and raised concerns about having a shuttle in orbit during the Y2K transition. Once the launch had slipped to Dec. 19, mission planners cut the mission from 10 to eight days, deleting one of the four spacewalks, to ensure a return before the end of the calendar year. The servicing mission couldn’t come soon enough, as a fourth gyroscope failed aboard Hubble in mid-November, with Discovery already poised on the launch pad to prepare for STS-103. Controllers placed Hubble in a safe mode until the astronauts arrived.
The STS-103 crew of C. Michael Foale, left, Claude Nicollier, Scott J. Kelly, Curtis L. Brown, Jean-François A. Clervoy, John M. Grunsfeld, and Steven L. Smith. The STS-103 crew patch. The mission patch for the Hubble Servicing Mission-3A. To execute the third Hubble Servicing Mission, in July 1998 NASA selected an experienced four-person team to carry out a record-breaking six spacewalks on the flight then planned for June 2000. The spacewalkers included Mission Specialists Steven L. Smith serving as payload commander, John M. Grunsfeld, C. Michael Foale, and European Space Agency (ESA) astronaut Claude Nicollier from Switzerland. The addition in March 1999 of Commander Curtis L. Brown, Pilot Scott J. Kelly, and Mission Specialist ESA astronaut Jean-François A. Clervoy of France rounded out the highly experienced crew with 18 previous spaceflights among them. Brown earned the distinction as only the fifth person to fly in space six times. For Kelly, STS-103 marked his first spaceflight. Smith, Clervoy, and Grunsfeld each had flown two previous missions, Foale four including a long-duration mission aboard Mir, and Nicollier three. Smith participated in three spacewalks during the second Hubble Servicing Mission and Nicollier served as the Remote Manipulator System (RMS) or robotic arm operator during the first.
The STS-103 crew at the traditional prelaunch breakfast at NASA’s Kennedy Space Center in Florida. Suited up, the STS-103 astronauts leave crew quarters for the trip to Launch Pad 39B. Space shuttle Discovery on Launch Pad 39B, awaiting launch. Discovery arrived back to KSC at the end of the STS-96 mission on June 6, 1999, and workers towed it to the Orbiter Processing Facility the same day to begin readying it for STS-103. The vehicle rolled over to the Vehicle Assembly Building on Nov. 4, where workers mated it with its external tank and twin solid rocket boosters, before rolling the stack out to Launch Pad 39B on Nov. 13.
Liftoff of space shuttle Discovery on the STS-103 Hubble Space Telescope servicing mission 3A. The Hubble Space Telescope as Discovery approaches. The STS-103 crew berthing the Hubble into the payload bay. Beginning its 27th trip into space, Discovery lifted off from Launch Pad 39B at 7:50 p.m. EST on Dec. 19 to fix the ailing space telescope. Two days later, Brown and Kelly maneuvered Discovery to within range of Hubble so Clervoy operating the 50-foot-long RMS could grapple the telescope and berth it into the payload bay.
During the first spacewalk, astronauts John M. Grunsfeld, left, and Steven L. Smith replacing one of the Rate Sensor Units containing two gyroscopes. Smith gives a thumbs up with his image reflected in the Hubble Space Telescope. Smith and Grunsfeld conducted the mission’s first spacewalk on Dec. 22, the flight’s fourth day in space. The duo, aided by Clervoy operating the RMS from inside Discovery, completed two of mission’s highest priority objectives. They replaced the failed gyroscopes, installing three new Rate Sensor Units, each containing two gyroscopes, to return control to the ailing telescope. They also installed six Voltage/Temperature Improvement Kits to prevent the telescope’s batteries from overheating as they aged. The excursion lasted eight hours 15 minutes, at the time the second longest spacewalk.
During the second spacewalk, astronauts C. Michael Foale, left, and Claude Nicollier during the changeout of the fine guidance sensor. Foale at the end of the Remote Manipulator System services the Hubble Space Telescope. The next day, Nicollier and Foale conducted the mission’s second spacewalk. The main task for this excursion involved installing a new computer aboard Hubble, replacing the original 1970s vintage unit. The new radiation-hardened system ran 20 times faster and carried six times more memory while using one-third the electrical power. They also installed a fine guidance sensor before concluding the eight-hour 10-minute spacewalk.
Astronauts Steven L. Smith, left, and John M. Grunsfeld begin their servicing activities during the third spacewalk. At the end of the third and final spacewalk, Grunsfeld, left, and Smith provide closing comments about the work the mission accomplished to service the Hubble Space Telescope. Smith and Grunsfeld ventured outside for a second time to complete the flight’s third and final spacewalk on Dec. 24, the first spacewalk conducted on Christmas Eve day. First, they replaced an old reel-to-reel tape recorder with a solid state unit providing a 10-fold increase in recording capability and replaced a failed data transmitter. They installed seven new covers on Hubble’s electronics bay doors for added protection of the telescope’s insulation. This third spacewalk lasted eight hours eight minutes.
The first space shuttle crew to celebrate Christmas in space, the STS-103 astronauts pose wearing Santa hats. The Hubble Space Telescope shortly after the STS-103 crew released it. The next day, the STS-103 astronauts earned the distinction as the first space shuttle crew to spend Christmas Day in space. Clervoy grappled Hubble, lifted it out of the payload bay and released it to continue its mission. Hubble Space Telescope Program Manager John H. Campbell said after the release, “The spacecraft is being guided by its new gyros under the control of its brand new computer. [It] is now orbiting freely and is in fantastic shape.” After deploying Hubble, the astronauts enjoyed a well-deserved Christmas dinner, with Clervoy providing French delicacies. The crew spent Dec. 26 readying Discovery for its return to Earth, including testing its reaction control system thrusters and aerodynamic surfaces and stowing unneeded gear.
Astronauts Steven L. Smith, left, Claude Nicollier, and John M. Grunsfeld complete their fluid loading protocol and put on their launch and entry suits prior to reentry. Space shuttle Discovery makes a perfect night landing at NASA’s Kennedy Space Center in Florida. The crew welcome home ceremony at Ellington Field in Houston. On Dec. 27, the astronauts donned their launch and entry suits and prepared for the return to Earth. They closed the payload bay doors and fired Discovery’s engines to bring them out of orbit. Just before landing, Kelly lowered the craft’s landing gear and Brown guided Discovery to a smooth night landing at KSC, concluding a flight of seven days, 23 hours, 11 minutes. They circled the Earth 119 times. The flight marked Discovery’s last solo flight as all its subsequent missions docked with the International Space Station. Workers at KSC began readying it for its next mission, STS-92 in October 2000.
The Hubble Space Telescope continues to operate today, far exceeding the five-year life extension expected from the last of the servicing missions in 2009. Joined in space by the James Webb Space Telescope in 2021, the two instruments together continue to image the skies across a broad range of the electromagnetic spectrum to provide scientists with the tools to gain unprecedented insights into the universe and its formation.
Watch the STS-103 crew narrate a video of their Hubble servicing mission.
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By NASA
NASA-supported scientists have suggested an updated framework for the role of ferns in environmental recovery from disaster. Instead of competing with other organisms, ferns may act as facilitators that ease the way for other plants and animals to re-establish themselves in a damaged landscape.
The study examines how a biosphere recovers from major upheaval, be it from wildfires or asteroid impacts, using what scientists call a ‘facilitative’ framework (where the actions of organisms help each other) rather than the long-held ‘competition-based’ framework.
NASA supported researchers at a fossil plant quarry near the Old Raton Pass Cretaceous–Paleogene (K-Pg) boundary in New Mexico.Ellen Currano Ferns are a common type of vascular plant found in woodlands, gardens, and many a plant pot on apartment shelves. Unlike many other vascular plants, ferns do not flower or seed. Instead, they reproduce via spores. Ferns first appeared on Earth some 360 million years ago during the Devonian period and, prior to the evolution of flowering plants, were the most common vascular plant on Earth.
Ferns are often one of the first plants to re-establish in areas affected by large-scale upheaval events, and it has been suggested that this is because ferns produce spores in great amounts that are widely distributed on the wind. Some scientists, particularly in the fields of geology and paleontology, have used this ‘competitive’ success of ferns as a foundation for ecological theories about how recolonization happens after upheavals.
However, in recent years, growing research has shown that recovery is not only about competition. Positive interactions, known as facilitation, between ferns and other species also play a significant role. The authors of the recent study believe that it is time to re-examine positive interactions within ecosystems, rather than defaulting to a competition framework.
Ferns in History
“I love to imagine ecosystems through time and play a game in my head where I ask myself, ’if I could stand here for 1 million years, would this fossilize?’” said lead author Lauren Azevedo Schmidt of the University of California at Davis. “Because of the mental time gymnastics I do, my research questions follow the same pathway. How do I create synergy between modern and paleo research?”
Early Paleocene fern fossil discovered on the Vermejo Park Ranch, NM. Photo by Ellen Currano.Ellen Currano The team examined ideas that have been developed based on observing modern organisms as well as ancient populations in the fossil record. They propose that, rather than out-competing other species, ferns act as facilitators for ecosystem recovery by stabilizing the ground, enhancing properties of the soil, and mediating competition between other organisms. This repositions ferns as facilitators of ecological recovery within disturbed habitats. This has broad implications for understanding how a community recovers and the importance of positive interactions following disturbance events. Because ferns are among the oldest lineages of plants on Earth and have experienced unimaginable climates and extinction events, they provide critical information to better understand the fossil record and Earth before humans.
Fossil plant excavation in the Cretaceous rocks just below the K-Pg boundary at Old Raton Pass, NM. Photo by Ellen Currano.Ellen Currano “The Cretaceous – Paleogene [K-Pg] extinction event reworked Earth’s biosphere, resulting in approximately 75% of species going extinct, with up to 90% of plants going extinct,” said Azevedo Schmidt. “This magnitude of devastation is something humans (luckily) have never had to deal with, making it hard to even think about. But it is something we must consider when tackling research/issues surrounding exobiology.”
The longevity of ferns on Earth provides a view into the evolution of life on Earth, even through some of the planet’s most devastating disasters. This is of interest to astrobiology and exobiology because exploring how environmental factors can and have impacted the large-scale evolution of life on Earth through mass extinctions and mass radiation events can help us understand the potential for the origin, evolution and distribution for life elsewhere in the Universe.
Ferns in Space
In addition to their relevance to astrobiology, the resilience of ferns and their ability to help heal a damaged environment could also make them important partners for future human missions in space. NASA’s Space Biology program has supported experiments to study how plants adapt to space with the expectation that knowledge gained can lead to ways by which crops can be cultivated for fresh food. Lessons learned from studying resilient plants, such as ferns, could guide efforts to make crops adapt better to harsh space conditions so they can serve as a reliable food source as humans explore destinations beyond our planet. Previous studies have also looked at how plants might keep air clean in enclosed spaces like the International Space Station or in habitats on the Moon or Mars.
NASA supported scientists can be seen prospecting for plant fossils in Berwind Canyon, CO. Photo by Ellen Currano.Ellen Currano “Ferns were able to completely transform Earth’s biosphere following the devastation of the K-Pg [Cretaceous–Paleogene] extinction event. The environment experienced continental-scale fires, acid rain, and nuclear winter, but ferns were able to tolerate unbelievable stress and make their environment better,” says Azevedo Schmidt. “I think we can all learn something from the mighty ferns.”
The study, “Ferns as facilitators of community recovery following biotic upheaval,” was published in the journal BioScience [doi:10.1093/biosci/biae022]
For more information on NASA’s Astrobiology program, visit:
https://www.science.nasa.gov/astrobiology
-end-
Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
LISTER (Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity) is one of 10 payloads flying aboard the next delivery for NASA’s CLPS (Commercial Lunar Payload Services) initiative. The instrument is equipped with a drilling system and thermal probe designed to dig into the lunar surface. Photo courtesy: Firefly Aerospace Earth’s nearest neighboring body in the solar system is its Moon, yet to date humans have physically explored just 5% of its surface. It wasn’t until 2023 – building on Apollo-era data and more detailed studies made in 2011-2012 by NASA’s automated GRAIL (Gravity Recovery and Interior Laboratory) mission – that researchers conclusively determined that the Moon has a liquid outer core surrounding a solid inner core.
As NASA and its industry partners plan for continued exploration of the Moon under Artemis in preparation for future long-duration missions to Mars, improving our understanding of Earth’s 4.5-billion-year-old Moon will help teams of researchers and astronauts find the safest ways to study and live and work on the lunar surface.
That improved understanding is the primary goal of a state-of-the-art science instrument called LISTER (Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity), one of 10 NASA payloads flying aboard the next delivery for the agency’s CLPS (Commercial Lunar Payload Services) initiative and set to be carried to the surface by Firefly Aerospace’s Blue Ghost 1 lunar lander.
Developed jointly by Texas Tech University in Lubbock and Honeybee Robotics of Altadena, California, LISTER will measure the flow of heat from the Moon’s interior. Its sophisticated pneumatic drill will penetrate to a depth of three meters into the dusty lunar regolith. Every half-meter it descends, the drilling system will pause and extend a custom-built thermal probe into the lunar regolith. LISTER will measure two different aspects of heat flow: thermal gradient, or the changes in temperature at various depths, and thermal conductivity, or the subsurface material’s ability to let heat pass through it.
“By making similar measurements at multiple locations on the lunar surface, we can reconstruct the thermal evolution of the Moon,” said Dr. Seiichi Nagihara, principal investigator for the mission and a geophysics professor at Texas Tech. “That will permit scientists to retrace the geological processes that shaped the Moon from its start as a ball of molten rock, which gradually cooled off by releasing its internal heat into space.”
Demonstrating the drill’s effectiveness could lead to more innovative drilling capabilities, enabling future exploration of the Moon, Mars, and other celestial bodies.. The science collected by LISTER aims to contribute to our knowledge of lunar geology, improving our ability to establish a long-term presence on the Moon under the Artemis campaign.
Under the CLPS model, NASA is investing in commercial delivery services to the Moon to enable industry growth and support long-term lunar exploration. As a primary customer for CLPS deliveries, NASA aims to be one of many customers on future flights. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the development of seven of the 10 CLPS payloads carried on Firefly’s Blue Ghost lunar lander.
Learn more about CLPS and Artemis at:
https://www.nasa.gov/clps
Alise Fisher
Headquarters, Washington
202-358-2546
Alise.m.fisher@nasa.gov
Corinne Beckinger
Marshall Space Flight Center, Huntsville, Ala.
256-544-0034
corinne.m.beckinger@nasa.gov
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Last Updated Dec 18, 2024 EditorBeth RidgewayContactCorinne M. Beckingercorinne.m.beckinger@nasa.govLocationMarshall Space Flight Center Related Terms
Commercial Lunar Payload Services (CLPS) Artemis Marshall Space Flight Center Explore More
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By NASA
X-rays are radiated by matter hotter than one million Kelvin, and high-resolution X-ray spectroscopy can tell us about the composition of the matter and how fast and in what direction it is moving. Quantum calorimeters are opening this new window on the Universe. First promised four decades ago, the quantum-calorimeter era of X-ray astronomy has finally dawned.
Photo of the XRISM/Resolve quantum-calorimeter array in its storage container prior to integration into the instrument. The 6×6 array, 5 mm on a side, consists of independent detectors – each one a thermally isolated silicon thermistor with a HgTe absorber. The spectrometer consisting of this detector and other essential technologies separates astrophysical X-ray spectra into about 2400 resolution elements, which can be thought of as X-ray colors.NASA GSFC A quantum calorimeter is a device that makes precise measurements of energy quanta by measuring the temperature change that occurs when a quantum of energy is deposited in an absorber with low heat capacity. The absorber is attached to a thermometer that is somewhat decoupled from a heat sink so that the sensor can heat up and then cool back down again. To reduce thermodynamic noise and the heat capacity of the sensor, operation at temperatures less than 0.1 K is required.
The idea for thermal measurement of small amounts of energy occurred in several places in the world independently when scientists observed pulses in the readout of low-temperature thermometers and infrared detectors. They attributed these spurious signals to passing cosmic-ray particles, and considered optimizing detectors for sensitive measurement of the energy of particles and photons.
The idea to develop such sensors for X-ray astronomy was conceived at Goddard Space Flight Center in 1982 when X-ray astronomers were considering instruments to propose for NASA’s planned Advanced X-ray Astrophysics Facility (AXAF). In a fateful conversation, infrared astronomer Harvey Moseley suggested thermal detection could offer substantial improvement over existing solid-state detectors. Using Goddard internal research and development funding, development advanced sufficiently to justify, just two years later, proposing a quantum-calorimeter X-ray Spectrometer (XRS) for inclusion on AXAF. Despite its technical immaturity at the time, the revolutionary potential of the XRS was acknowledged, and the proposal was accepted.
The AXAF design evolved over the subsequent years, however, and the XRS was eliminated from its complement of instruments. After discussions between NASA and the Japanese Institute of Space and Astronautical Science (ISAS), a new XRS was included in the instrument suite of the Japanese Astro-E X-ray observatory. Astro-E launched in 2000 but did not reach orbit due to an anomaly in the first stage of the rocket. Astro-E2, a rebuild of Astro-E, was successfully placed in orbit in 2005 and renamed Suzaku, but the XRS instrument ceased operation before observations started due to loss of the liquid helium, an essential part of the detector cooling system, caused by a faulty storage system.
A redesigned mission, Astro-H, that included a quantum-calorimeter instrument with a redundant cooling system was successfully launched in 2016 and renamed Hitomi. Hitomi’s Soft X-ray Spectrometer (SXS) obtained high resolution spectra of the Perseus cluster of galaxies and a few other sources before a problem with the attitude control system caused the mission to be lost roughly one month after launch. Even so, Hitomi was the first orbiting observatory to obtain a scientific result using X-ray quantum calorimeters. The spectacular Perseus spectrum generated by the SXS motivated yet another attempt to implement a spaceborne quantum-calorimeter spectrometer.
The X-ray Imaging and Spectroscopy Mission (XRISM) was launched in September 2023, with the spectrometer aboard renamed Resolve to represent not only its function but also the resolve of the U.S./Japan collaboration to study the Universe through the window of this new capability. XRISM has been operating well in orbit for over a year.
Development of the Sensor Technology
Development of the sensor technology employed in Resolve began four decades ago. Note that an X-ray quantum-calorimeter spectrometer requires more than the sensor technology. Other technologies, such as the coolers that provide a
The sensors used from XRS through Resolve were all based on silicon-thermistor thermometers and mercury telluride (HgTe) X-ray absorbers. They used arrays consisting of 32 to 36 pixels, each of which was an independent quantum calorimeter. Between Astro-E and Astro-E2, a new method of making the thermistor was developed that significantly reduced its low-frequency noise. Other fabrication advances made it possible to make reproducible connections between absorbers and thermistors and to fit each thermistor and its thermal isolation under its X-ray absorber, making square arrays feasible.
Through a Small Business Innovation Research (SBIR) contract executed after the Astro-E2 mission, EPIR Technologies Inc. reduced the specific heat of the HgTe absorbers. Additional improvements made to the cooler of the detector heat sink allowed operation at a lower temperature, which further reduced the specific heat. Together, these changes enabled the pixel width to be increased from 0.64 mm to 0.83 mm while still achieving a lower heat capacity, and thus improving the energy resolution. From Astro-E through Astro-H, the energy resolution for X-rays of energy around 6000 eV improved from 11 eV, to 5.5 eV, to 4 eV. No changes to the array design were made between Astro-H and XRISM.
Resolve detector scientist Caroline Kilbourne installing the flight Resolve quantum-calorimeter array into the assembly that provides its electrical, thermal, and mechanical interfaces.NASA GSFC Over the same period, other approaches to quantum-calorimeter arrays optimized for the needs of future missions were developed. The use of superconducting transition-edge sensors (TES) instead of silicon (Si) thermistors led to improved energy resolution, more pixels per array, and multiplexing (a technique that allows multiple signals to be carried on a single wire). Quantum-calorimeter arrays with thousands of pixels are now standard, such as in the NASA contribution to the future European New Advanced Telescope for High-ENergy Astrophysics (newAthena) mission. And quantum calorimeters using paramagnetic thermometers — which unlike TES and Si thermistors require no dissipation of heat in the thermometer for it to be read out — combined with high-density wiring are a promising route for realizing even larger arrays. (See Astrophysics Technology Highlight on these latest developments.)
The Resolve instrument aboard XRISM (X-ray Imaging and Spectroscopy Mission) captured data from the center of galaxy NGC 4151, where a supermassive black hole is slowly consuming material from the surrounding accretion disk. The resulting spectrum reveals the presence of iron in the peak around 6.5 keV and the dips around 7 keV, light thousands of times more energetic that what our eyes can see. Background: An image of NGC 4151 constructed from a combination of X-ray, optical, and radio light.Spectrum: JAXA/NASA/XRISM Resolve. Background: X-rays, NASA/CXC/CfA/J.Wang et al.; optical, Isaac Newton Group of Telescopes, La Palma/Jacobus Kapteyn Telescope; radio, NSF/NRAO/VLA Results from Resolve
So, what is Resolve revealing about the Universe? Through spectroscopy alone, Resolve allows us to construct images of complex environments where collections of gas and dust with various attributes exist, emitting and absorbing X-rays at energies characteristic of their various compositions, velocities, and temperatures. For example, in the middle of the galaxy known as NCG 4151 (see figure above), matter spiraling into the central massive black hole forms a circular structure that is flat near the black hole, more donut-shaped further out, and, according to the Resolve data, a bit lumpy. Matter near the black hole is heated up to X-ray-emitting temperatures and irradiates the matter in the circular structure. The Resolve spectrum has a bright narrow emission line (peak) from neutral iron atoms that must be coming from colder matter in the circular structure, because hotter material would be ionized, and would have a different emission signature. Nonetheless, the shape of the iron line needs three components to describe it, each coming from a different lump in the circular structure. The presence of absorption lines (dips) in the spectrum provides further detail about the structure of the infalling matter.
A second example is the detection of X-ray emission by Resolve from the debris of stars that have exploded, such as N132D (see figure below), that will improve our understanding of the explosion mechanism and how the elements produced in stars get distributed, and allow us to infer the type of star each was before ending in a supernova. Elements are identified by their characteristic emission lines, and shifts of those lines via the Doppler effect tell us how fast the material is moving.
XRISM’s Resolve instrument captured data from supernova remnant N132D in the Large Magellanic Cloud to create the most detailed X-ray spectrum of the object ever made. The spectrum reveals peaks associated with silicon, sulfur, argon, calcium, and iron. Inset at right is an image of N132D captured by XRISM’s Xtend instrument.JAXA/NASA/XRISM Resolve and Xtend These results are just the beginning. The rich Resolve data sets are identifying complex velocity structures, rare elements, and multiple temperature components in a diverse ensemble of cosmic objects. Welcome to the quantum calorimeter era! Stay tuned for more revelations!
Project Leads: Dr. Caroline Kilbourne, NASA Goddard Space Flight Center (GSFC), for silicon-thermistor quantum calorimeter development from Astro-E2 through XRISM and early TES development. Foundational and other essential leadership provided by Dr. Harvey Moseley, Dr. John Mather, Dr. Richard Kelley, Dr. Andrew Szymkowiak, Mr. Brent Mott, Dr. F. Scott Porter, Ms. Christine Jhabvala, Dr. James Chervenak (GSFC at the time of the work) and Dr. Dan McCammon (U. Wisconsin).
Sponsoring Organizations and Programs: The NASA Headquarters Astrophysics Division sponsored the projects, missions, and other efforts that culminated in the development of the Resolve instrument.
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