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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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By NASA
A salute is widely recognized as a display of respect, but did you know it also means ‘hello’ in American Sign Language?
It is one of the signs that Jesse Bazley, International Space Station/Commercial Low Earth Orbit Development Program integration team lead, subtly incorporates into his daily interactions with colleagues at NASA’s Johnson Space Center in Houston.
In May 2021, Jesse Bazley worked his final shift as an Environmental and Thermal Operating Systems flight controller in the Mission Control Center at NASA’s Johnson Space Center in Houston. Image courtesy of Jesse Bazley Bazley is hard of hearing, which has at times presented challenges in his daily work – particularly during his stint as an Environmental and Thermal Operating Systems flight controller for the space station. “Working on console [in the Mission Control Center], you must listen to dozens of voice loops at a time, sometimes in different languages,” he said, adding that the standard-issue headset for flight controllers was not compatible with his hearing aids. Bazley adapted by obtaining a headset that fit over his hearing aids, learning how to adjust the audio system’s volume, and limiting over-the-air discussions when possible.
Bazley has been part of the NASA team for 17 years, filling a variety of roles that support the International Space Station. One of his proudest achievements occurred early in his tenure. Bazley was an intern at Marshall Space Flight Center in Huntsville, Alabama, in 2006 when the space station’s Water Recovery System was being tested. The system converts the station’s wastewater into drinkable water for the crew. When he arrived at Johnson one year later, his first assignment was to assist with the system’s procedure and display development for its incorporation into the space station’s core operations. “Now, 16 years later, it is commonplace for the space station to ‘turn yesterday’s coffee into tomorrow’s coffee’,” he said.
Jesse Bazley supporting the Atmosphere and Consumables Engineer console during the STS-127 mission in July 2009. NASA His favorite project so far has been integrating the station’s Thermal Amine Scrubber – which removes carbon dioxide from the air – into station operations. “I worked it from the beginning of NASA’s involvement, helping the provider with software testing and the integration of a brand-new Mission Control Center communications architecture,” he said.
Today, Bazley works to integrate subject matter experts from Johnson’s Flight Operations Directorate (FOD) into the processes of the International Space Station and Commercial Low Earth Orbit Development Programs. “I help pull together FOD positions on topics and coordinate reviews of provider materials to ensure that the operations perspective is maintained as development moves forward,” he explained.
While Bazley no longer supports a console, he must continue adapting to difficult hearing environments. He uses the captioning tools available through videoconferencing software during frequent team meetings, for example. “It’s important to understand that people have visible and invisible disabilities,” he said. “Sometimes their request for a remote option is not because they want to avoid an in-person meeting. It may be that they work best using the features available in that virtual environment.”
Bazley also chairs the No Boundaries Employee Resource Group, which promotes the development, inclusion, and innovation of Johnson’s workforce with a focus on employees with disabilities and employees who are caregivers of family members with disabilities.
From these diverse roles and experiences, Bazley has learned to listen to his gut instincts. “In flight operations, you must work with short timelines when things happen in-orbit, so you have to trust your training,” he said. “Understanding when you have enough information to proceed is critical to getting things done.”
Bazley looks forward to the further commercialization of low Earth orbit so NASA can focus resources on journeying to the Moon and Mars. “Aviation started out as government-funded and now is commonplace for the public. I look forward to seeing how that evolution progresses in low Earth orbit.”
His advice to the Artemis Generation is to consider the long-term impact of their actions and decisions. “What looks great on paper may not be a great solution when you have to send 10 commands just to do one task, or when the crew has to put their hand deep into the spacecraft to actuate a manual override,” he said. “The decisions you make today will be felt by operations in the future.”
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By NASA
3 min read
NASA Develops Process to Create Very Accurate Eclipse Maps
New NASA research reveals a process to generate extremely accurate eclipse maps, which plot the predicted path of the Moon’s shadow as it crosses the face of Earth. Traditionally, eclipse calculations assume that all observers are at sea level on Earth and that the Moon is a smooth sphere that is perfectly symmetrical around its center of mass. As such, these calculations do not take into account different elevations on Earth or the Moon’s cratered, uneven surface.
For slightly more accurate maps, people can employ elevation tables and plots of the lunar limb — the edge of the visible surface of the Moon as seen from Earth. However, now eclipse calculations have gained even greater accuracy by incorporating lunar topography data from NASA’s LRO (Lunar Reconnaissance Orbiter) observations.
Using LRO elevation maps, NASA visualizer Ernie Wright at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, created a continuously varying lunar limb profile as the Moon’s shadow passes over the Earth. The mountains and valleys along the edge of the Moon’s disk affect the timing and duration of totality by several seconds. Wright also used several NASA data sets to provide an elevation map of Earth so that eclipse observer locations were depicted at their true altitude.
The resulting visualizations show something never seen before: the true, time-varying shape of the Moon’s shadow, with the effects of both an accurate lunar limb and the Earth’s terrain.
“Beginning with the 2017 total solar eclipse, we’ve been publishing maps and movies of eclipses that show the true shape of the Moon’s central shadow — the umbra,” said Wright.
A map showing the umbra (the Moon’s central shadow) as it passes over Cleveland at 3:15 p.m. local time during the April 8, 2024, total solar eclipse. NASA SVS/Ernie Wright and Michaela Garrison “And people ask, why does it look like a potato instead of a smooth oval? The short answer is that the Moon isn’t a perfectly smooth sphere.”
The mountains and valleys around the edge of the Moon change the shape of the shadow. The valleys are also responsible for Baily’s beads and the diamond ring, the last bits of the Sun visible just before and the first just after totality.
A computer simulation of Baily’s beads during a total solar eclipse. Data from Lunar Reconnaissance Orbiter makes it possible to map the lunar valleys that create the bead effect. NASA SVS/Ernie Wright Wright is lead author of a paper published September 19 in The Astronomical Journal that reveals for the first time exactly how the Moon’s terrain creates the umbra shape. The valleys on the edge of the Moon act like pinholes projecting images of the Sun onto the Earth’s surface.
A visualization of Sun images being projected from lunar valleys that are acting like pinhole projectors. Light rays from the Sun converge on each valley, then spread out again on their way to the Earth. NASA SVS/Ernie Wright The umbra is the small hole in the middle of these projected Sun images, the place where none of the Sun images reach.
Viewed from behind the Moon, the Sun images projected by lunar valleys on the Moon’s edge fall on the Earth’s surface in a flower-like pattern with a hole in the middle, forming the umbra shape. NASA SVS/Ernie Wright The edges of the umbra are made up of small arcs from the edges of the projected Sun images.
This is just one of several surprising results that have emerged from the new eclipse mapping method described in the paper. Unlike the traditional method invented 200 years ago, the new way renders eclipse maps one pixel at a time, the same way 3D animation software creates images. It’s also similar to the way other complex phenomena, like weather, are modeled in the computer by breaking the problem into millions of tiny pieces, something computers are really good at, and something that was inconceivable 200 years ago.
For more about eclipses, refer to:
https://science.nasa.gov/eclipses
By Ernie Wright and Susannah Darling
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Nancy Neal-Jones
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-0039
nancy.n.jones@nasa.gov
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Last Updated Sep 19, 2024 Editor wasteigerwald Contact wasteigerwald william.a.steigerwald@nasa.gov Location NASA Goddard Space Flight Center Related Terms
Lunar Reconnaissance Orbiter (LRO) Solar Eclipses Uncategorized Explore More
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By NASA
NASA and Boeing welcomed Starliner back to Earth following the uncrewed spacecraft’s successful landing at 10:01 p.m. MDT Sept. 6, 2024, at the White Sands Space Harbor in New Mexico. Credit: NASA NASA and Boeing safely returned the uncrewed Starliner spacecraft following its landing at 10:01 p.m. MDT Sept. 6 at White Sands Space Harbor in New Mexico, concluding a three-month flight test to the International Space Station.
“I am extremely proud of the work our collective team put into this entire flight test, and we are pleased to see Starliner’s safe return,” said Ken Bowersox, associate administrator, Space Operations Mission Directorate at NASA Headquarters in Washington. “Even though it was necessary to return the spacecraft uncrewed, NASA and Boeing learned an incredible amount about Starliner in the most extreme environment possible. NASA looks forward to our continued work with the Boeing team to proceed toward certification of Starliner for crew rotation missions to the space station.”
The flight on June 5 was the first time astronauts launched aboard the Starliner. It was the third orbital flight of the spacecraft, and its second return from the orbiting laboratory. Starliner now will ship to NASA’s Kennedy Space Center in Florida for inspection and processing.
NASA’s Commercial Crew Program requires a spacecraft to fly a crewed test flight to prove the system is ready for regular flights to and from the orbiting laboratory. Following Starliner’s return, the agency will review all mission-related data.
“We are excited to have Starliner home safely. This was an important test flight for NASA in setting us up for future missions on the Starliner system,” said Steve Stich, manager of NASA’s Commercial Crew Program. “There was a lot of valuable learning that will enable our long-term success. I want to commend the entire team for their hard work and dedication over the past three months.”
NASA astronauts Butch Wilmore and Suni Williams launched on June 5 aboard Starliner for the agency’s Boeing Crewed Flight Test from Cape Canaveral Space Force Station in Florida. On June 6, as Starliner approached the space station, NASA and Boeing identified helium leaks and experienced issues with the spacecraft’s reaction control thrusters. Following weeks of in-space and ground testing, technical interchange meetings, and agency reviews, NASA made the decision to prioritize safety and return Starliner without its crew. Wilmore and Williams will continue their work aboard station as part of the Expedition 71/72 crew, returning in February 2025 with the agency’s SpaceX Crew-9 mission.
The crew flight test is part of NASA’s Commercial Crew Program. The goal of NASA’s Commercial Crew Program is safe, reliable, and cost-effective transportation to and from the International Space Station and low Earth orbit. This already is providing additional research time and has increased the opportunity for discovery aboard humanity’s microgravity testbed, including helping NASA prepare for human exploration of the Moon and Mars.
Learn more about NASA’s Commercial Crew program at:
https://www.nasa.gov/commercialcrew
-end-
Joshua Finch / Jimi Russell
Headquarters, Washington
202-358-1100
joshua.a.finch@nasa.gov / james.j.russell@nasa.gov
Leah Cheshier
Johnson Space Center, Houston
281-483-5111
leah.d.cheshier@nasa.gov
Steve Siceloff / Danielle Sempsrott / Stephanie Plucinsky
Kennedy Space Center, Florida
321-867-2468
steven.p.siceloff@nasa.gov / danielle.c.sempsrott@nasa.gov / stephanie.n.plucinsky@nasa.gov
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Last Updated Sep 07, 2024 EditorJessica TaveauLocationNASA Headquarters Related Terms
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