In a stunning new development, NASA scientists have confirmed that the Curiosity rover has discovered the largest organic molecules ever found on the Martian surface. The groundbreaking analysis of an existing rock sample, “Cumberland,” within Curiosity’s onboard lab revealed the presence of decane, undecane, and dodecane – compounds with 10, 11, and 12 carbon atoms respectively.
These molecules are believed to be fragments of preserved fatty acids, key building blocks of life as we know it on Earth. While non-biological origins are possible, the size of these newly detected molecules significantly boosts the potential for the preservation of complex biosignatures on the red planet.
This discovery builds upon years of tantalizing findings by Curiosity, including the detection of smaller organic molecules, organic salts, and the measurement of total organic carbon comparable to Earth’s most extreme environments. The new data suggests that larger, more complex organic compounds could have survived for billions of years despite harsh Martian conditions.
The network of cracks in this Martian rock slab called “Old Soaker” may have formed from the drying of a mud layer more than 3 billion years ago. The view spans about 3 feet (90 centimeters) left-to-right and combines three images taken by the MAHLI camera on the arm of NASA’s Curiosity Mars rover. Credits: NASA/JPL-Caltech/MSSS
Lead author Caroline Freissinet emphasized the significance, stating, “Our study proves that, even today, by analyzing Mars samples, we could detect chemical signatures of past life—if it ever existed on Mars.”
Scientists are particularly intrigued by the carbon chain length of the presumed fatty acids (11-13 carbons), as non-biological processes typically yield shorter chains. This raises the exciting possibility of longer-chain fatty acids, often associated with biological activity, being present.
While the exact origin of these molecules remains under investigation, this major breakthrough reinforces the critical need for Mars Sample Return missions to conduct in-depth analysis with advanced Earth-based instruments.
“We are ready to take the next big step and bring Mars samples home to our labs to settle the debate about life on Mars,” declared Dr. Daniel Glavin.
This latest discovery marks a significant leap in our understanding of Martian organic chemistry and further fuels the compelling narrative that Mars may have once harbored the conditions necessary for life. The search for evidence of past life on the red planet has just intensified.
NASA’s James Webb Space Telescope shows off its capabilities closer to home with its first image of Neptune. Not only has Webb captured the clearest view of this distant planet’s rings in more than 30 years, but its cameras reveal the ice giant in a whole new light.
Most striking in Webb’s new image is the crisp view of the planet’s rings – some of which have not been detected since NASA’s Voyager 2 became the first spacecraft to observe Neptune during its flyby in 1989. In addition to several bright, narrow rings, the Webb image clearly shows Neptune’s fainter dust bands.
“It has been three decades since we last saw these faint, dusty rings, and this is the first time we’ve seen them in the infrared,” notes Heidi Hammel, a Neptune system expert and interdisciplinary scientist for Webb. Webb’s extremely stable and precise image quality permits these very faint rings to be detected so close to Neptune.
Neptune has fascinated researchers since its discovery in 1846. Located 30 times farther from the Sun than Earth, Neptune orbits in the remote, dark region of the outer solar system. At that extreme distance, the Sun is so small and faint that high noon on Neptune is similar to a dim twilight on Earth.
Webb’s Near-Infrared Camera (NIRCam) images objects in the near-infrared range from 0.6 to 5 microns, so Neptune does not appear blue to Webb. In fact, the methane gas so strongly absorbs red and infrared light that the planet is quite dark at these near-infrared wavelengths, except where high-altitude clouds are present. Such methane-ice clouds are prominent as bright streaks and spots, which reflect sunlight before it is absorbed by methane gas. Credits: NASA, ESA, CSA, STScI
This planet is characterized as an ice giant due to the chemical make-up of its interior. Compared to the gas giants, Jupiter and Saturn, Neptune is much richer in elements heavier than hydrogen and helium. This is readily apparent in Neptune’s signature blue appearance in Hubble Space Telescope images at visible wavelengths, caused by small amounts of gaseous methane.
Webb’s Near-Infrared Camera (NIRCam) images objects in the near-infrared range from 0.6 to 5 microns, so Neptune does not appear blue to Webb. In fact, the methane gas so strongly absorbs red and infrared light that the planet is quite dark at these near-infrared wavelengths, except where high-altitude clouds are present. Such methane-ice clouds are prominent as bright streaks and spots, which reflect sunlight before it is absorbed by methane gas. Images from other observatories, including the Hubble Space Telescope and the W.M. Keck Observatory, have recorded these rapidly evolving cloud features over the years.
More subtly, a thin line of brightness circling the planet’s equator could be a visual signature of global atmospheric circulation that powers Neptune’s winds and storms. The atmosphere descends and warms at the equator, and thus glows at infrared wavelengths more than the surrounding, cooler gases.
Neptune’s 164-year orbit means its northern pole, at the top of this image, is just out of view for astronomers, but the Webb images hint at an intriguing brightness in that area. A previously-known vortex at the southern pole is evident in Webb’s view, but for the first time Webb has revealed a continuous band of high-latitude clouds surrounding it.
What do we see in Webb’s latest image of the ice giant Neptune? Webb captured seven of Neptune’s 14 known moons: Galatea, Naiad, Thalassa, Despina, Proteus, Larissa, and Triton. Neptune’s large and unusual moon, Triton, dominates this Webb portrait of Neptune as a very bright point of light sporting the signature diffraction spikes seen in many of Webb’s images. Credits: NASA, ESA, CSA, STScI
Webb also captured seven of Neptune’s 14 known moons. Dominating this Webb portrait of Neptune is a very bright point of light sporting the signature diffraction spikes seen in many of Webb’s images, but this is not a star. Rather, this is Neptune’s large and unusual moon, Triton.
Covered in a frozen sheen of condensed nitrogen, Triton reflects an average of 70 percent of the sunlight that hits it. It far outshines Neptune in this image because the planet’s atmosphere is darkened by methane absorption at these near-infrared wavelengths. Triton orbits Neptune in an unusual backward (retrograde) orbit, leading astronomers to speculate that this moon was originally a Kuiper belt object that was gravitationally captured by Neptune. Additional Webb studies of both Triton and Neptune are planned in the coming year.
The Mars lander’s seismometer has picked up vibrations from four separate impacts in the past two years, which is the first of its kind to have recorded seismic and acoustic waves from an impact on the Red Planet.
NASA’s InSight lander has detected seismic waves from four space rocks that crashed on Mars in 2020 and 2021, detected by the spacecraft’s seismometer since its landing in 2018.
A new paper published Monday in Nature Geoscience details the impacts, which ranged between 53 and 180 miles (85 and 290 kilometers) from InSight’s location, a region of Mars called Elysium Planitia.
The first of the four confirmed meteoroids – the term used for space rocks before they hit the ground – made the most dramatic entrance: It entered Mars’ atmosphere on Sept. 5, 2021, exploding into at least three shards that each left a crater behind.
Credit: NASA/JPL-Caltech
Then, NASA’s Mars Reconnaissance Orbiter flew over the estimated impact site and confirmed the location using its black-and-white Context Camera to find three darkened spots on the surface. After locating these spots, the orbiter used the High-Resolution Imaging Science Experiment camera, or HiRISE, to get a color close-up of the craters.
“After three years of InSight waiting to detect an impact, those craters looked beautiful,” said Ingrid Daubar of Brown University, a co-author of the paper and a specialist in Mars impacts. Finally, scientists confirmed three other impacts had occurred on May 27, 2020; Feb. 18, 2021; and Aug. 31, 2021.
Researchers have puzzled over why they haven’t detected more meteoroid impacts on Mars. The Red Planet is next to the solar system’s main asteroid belt, which provides an ample supply of space rocks to scar the planet’s surface. Because Mars’ atmosphere is just 1% as thick as Earth’s, more meteoroids pass through it without disintegrating.
InSight’s seismometer has also detected over 1,300 marsquakes. Provided by France’s space agency, the Centre National d’Études Spatiales, the instrument is so sensitive that it can detect seismic waves from thousands of miles away. But the Sept. 5, 2021, event marks the first time an impact was confirmed as the cause of such waves.
InSight’s team suspects that other impacts may have been obscured by noise from wind or by seasonal changes in the atmosphere. But now that the distinctive seismic signature of an impact on Mars has been discovered, scientists expect to find more hiding within InSight’s nearly four years of data.
Listen to a Meteoroid Hitting the Red Planet
The sound of a meteoroid striking Mars – created from data recorded by NASA’s InSight lander – is like a “bloop” due to a peculiar atmospheric effect. In this audio clip, the sound can be heard three times: when the meteoroid enters the Martian atmosphere, explodes into pieces, and impacts the surface.
The four meteoroid impacts confirmed so far produced small quakes with a magnitude of no more than 2.0. Those smaller quakes provide scientists with only a glimpse into the Martian crust, while seismic signals from larger quakes, like the magnitude 5 event that occurred in May 2022, can also reveal details about the planet’s mantle and core.
But the impacts will be critical to refining Mars’ timeline. “Impacts are the clocks of the solar system,” said the paper’s lead author, Raphael Garcia of Institut Supérieur de l’Aéronautique et de l’Espace in Toulouse, France. “We need to know the impact rate today to estimate the age of different surfaces.”
Scientists can approximate the age of a planet’s surface by counting its impact craters: The more they see, the older the surface. By calibrating their statistical models based on how often they see impacts occurring now, scientists can then estimate how many more impacts happened earlier in the solar system’s history.
InSight’s data, in combination with orbital images, can be used to rebuild a meteoroid’s trajectory and the size of its shock wave. Every meteoroid creates a shock wave as it hits the atmosphere and an explosion as it hits the ground. These events send sound waves through the atmosphere. The bigger the explosion, the more this sound wave tilts the ground when it reaches InSight. The lander’s seismometer is sensitive enough to measure how much the ground tilts from such an event and in what direction.
“We’re learning more about the impact process itself,” Garcia said. “We can match different sizes of craters to specific seismic and acoustic waves now.”
The lander still has time to study Mars. Dust buildup on the lander’s solar panels is reducing its power and will eventually lead to the spacecraft shutting down. Predicting precisely when is difficult, but based on the latest power readings, engineers now believe the lander could shut down between October of this year and January 2023.
NASA’s Perseverance rover is well into its second science campaign, collecting rock-core samples from features within an area long considered by scientists to be a top prospect for finding signs of ancient microbial life on Mars. The rover has collected four samples from an ancient river delta in the Red Planet’s Jezero Crater since July 7, bringing the total count of scientifically compelling rock samples to 12.
“We picked the Jezero Crater for Perseverance to explore because we thought it had the best chance of providing scientifically excellent samples – and now we know we sent the rover to the right location,” said Thomas Zurbuchen, NASA’s associate administrator for science in Washington. “These first two science campaigns have yielded an amazing diversity of samples to bring back to Earth by the Mars Sample Return campaign.”
Twenty-eight miles (45 kilometers) wide, Jezero Crater hosts a delta – an ancient fan-shaped feature that formed about 3.5 billion years ago at the convergence of a Martian river and a lake. Perseverance is currently investigating the delta’s sedimentary rocks, formed when particles of various sizes settled in the once-watery environment. During its first science campaign, the rover explored the crater’s floor, finding igneous rock, which forms deep underground from magma or during volcanic activity at the surface.
“The delta, with its diverse sedimentary rocks, contrasts beautifully with the igneous rocks – formed from crystallization of magma – discovered on the crater floor,” said Perseverance project scientist Ken Farley of Caltech in Pasadena, California. “This juxtaposition provides us with a rich understanding of the geologic history after the crater formed and a diverse sample suite. For example, we found a sandstone that carries grains and rock fragments created far from Jezero Crater – and a mudstone that includes intriguing organic compounds.”
NASA’s Perseverance rover puts its robotic arm to work around a rocky outcrop called “Skinner Ridge” in Mars’ Jezero Crater. Composed of multiple images, this mosaic shows layered sedimentary rocks in the face of a cliff in the delta, as well as one of the locations where the rover abraded a circular patch to analyze a rock’s composition. Credits: NASA/JPL-Caltech/ASU/MSSS
“Wildcat Ridge” is the name given to a rock about 3 feet (1 meter) wide that likely formed billions of years ago as mud and fine sand settled in an evaporating saltwater lake. On July 20, the rover abraded some of the surface of Wildcat Ridge so it could analyze the area with the instrument called Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC.
SHERLOC’s analysis indicates the samples feature a class of organic molecules that are spatially correlated with those of sulfate minerals. Sulfate minerals found in layers of sedimentary rock can yield significant information about the aqueous environments in which they formed.
What Is Organic Matter?
Organic molecules consist of a wide variety of compounds made primarily of carbon and usually include hydrogen and oxygen atoms. They can also contain other elements, such as nitrogen, phosphorus, and sulfur. While there are chemical processes that produce these molecules that don’t require life, some of these compounds are the chemical building blocks of life. The presence of these specific molecules is considered to be a potential biosignature – a substance or structure that could be evidence of past life but may also have been produced without the presence of life.
In 2013, NASA’s Curiosity Mars rover found evidence of organic matter in rock-powder samples, and Perseverance has detected organics in Jezero Crater before. But unlike that previous discovery, this latest detection was made in an area where, in the distant past, sediment and salts were deposited into a lake under conditions in which life could potentially have existed. In its analysis of Wildcat Ridge, the SHERLOC instrument registered the most abundant organic detections on the mission to date.
“In the distant past, the sand, mud, and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could potentially have thrived,” said Farley. “The fact the organic matter was found in such a sedimentary rock – known for preserving fossils of ancient life here on Earth – is important. However, as capable as our instruments aboard Perseverance are, further conclusions regarding what is contained in the Wildcat Ridge sample will have to wait until it’s returned to Earth for in-depth study as part of the agency’s Mars Sample Return campaign.”
Rendering of Perseverance, whose RIMFAX technology is exploring what lies beneath the Martian surface. Photo: NASA/JPL/Caltech/FFI
The first step in the NASA-ESA (European Space Agency) Mars Sample Return campaign began when Perseverance cored its first rock sample in September 2021. Along with its rock-core samples, the rover has collected one atmospheric sample and two witness tubes, all of which are stored in the rover’s belly.
The geologic diversity of the samples already carried in the rover is so good that the rover team is looking into depositing select tubes near the base of the delta in about two months. After depositing the cache, the rover will continue its delta explorations.
“I’ve studied Martian habitability and geology for much of my career and know first-hand the incredible scientific value of returning a carefully collected set of Mars rocks to Earth,” said Laurie Leshin, director of NASA’s Jet Propulsion Laboratory in Southern California. “That we are weeks from deploying Perseverance’s fascinating samples and mere years from bringing them to Earth so scientists can study them in exquisite detail is truly phenomenal. We will learn so much.”
More About the Mission
A key objective for Perseverance’s mission on Mars is astrobiology, including caching samples that may contain signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.
Subsequent NASA missions, in cooperation with ESA, would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.
The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.
NASA/Photo: Nasa.gov
JPL, which is managed for NASA by Caltech, built and manages operations of the Perseverance rover.
Thousands of never-before-seen young stars spotted in a stellar nursery called 30 Doradus, captured by NASA’s James Webb Space Telescope, called Tarantula Nebula owing to its appearance in dusty filaments.
The nebula has long been a favorite for astronomers studying star formation and the Webb has been revealing beautiful distant background galaxies, as well as the detailed structure and composition of the nebula’s gas and dust ever since it’s started capturing the deep space.
At only 161,000 light-years away in the Large Magellanic Cloud galaxy, the Tarantula Nebula is the largest and brightest star-forming region in the Local Group, the galaxies nearest our Milky Way. It is home to the hottest, most massive stars known. Astronomers focused three of Webb’s high-resolution infrared instruments on the Tarantula. Under the lens of Webb’s Near-Infrared Camera (NIRCam), the region resembles a burrowing tarantula’s home, lined with its silk.
The nebula’s cavity centered in the image above has been hollowed out by blistering radiation from a cluster of massive young stars, which sparkle pale blue in the image. Only the densest surrounding areas of the nebula resist erosion by these stars’ powerful stellar winds, forming pillars that appear to point back toward the cluster. These pillars contain forming protostars, which will eventually emerge from their dusty cocoons and take their turn shaping the nebula.
Caption: Nestled in the center of the Tarantula Nebula in the Large Magellanic Cloud is the largest star yet discovered, astronomers have produced the sharpest image ever of this star. Photo:Observatory/NOIRLab/NSF/AURA Acknowledgment
Webb’s Near-Infrared Spectrograph (NIRSpec) caught one very young star doing precisely emerging out of the dust. Astronomers previously thought this star might be a bit older and already in the process of clearing out a bubble around itself. However, NIRSpec showed that the star was only just beginning to emerge from its pillar and still maintained an insulating cloud of dust around itself. Without Webb’s high-resolution spectra at infrared wavelengths, this episode of star formation-in-action could not have been revealed.
The region takes on a different appearance when viewed in the longer infrared wavelengths detected by Webb’s Mid-infrared Instrument (MIRI). The hot stars fade, and the cooler gas and dust glow. Within the stellar nursery clouds, points of light indicate embedded protostars, still gaining mass.
While shorter wavelengths of light are absorbed or scattered by dust grains in the nebula, and therefore never reach Webb to be detected, longer mid-infrared wavelengths penetrate that dust, ultimately revealing a previously unseen cosmic environment.
Caption: NASA’s James Webb Space Telescope
One of the reasons the Tarantula Nebula is interesting to astronomers is that the nebula has a similar type of chemical composition as the gigantic star-forming regions observed at the universe’s “cosmic noon,” when the cosmos was only a few billion years old and star formation was at its peak. Star-forming regions in our Milky Way galaxy are not producing stars at the same furious rate as the Tarantula Nebula, and have a different chemical composition.
Caption: In this mosaic image displays the Tarantula Nebula star, including tens of thousands of never-before-seen young stars that were previously shrouded in cosmic dust. The most active region appears to sparkle with massive young stars, appearing pale blue./Photo:NASA
This makes the Tarantula the closest (i.e., easiest to see in detail) example of what was happening in the universe as it reached its brilliant high noon. Webb will provide astronomers the opportunity to compare and contrast observations of star formation in the Tarantula Nebula with the telescope’s deep observations of distant galaxies from the actual era of cosmic noon.
Roving the Red Planet. Perseverance landed on Mars in February 2021 and has been gathering data on the planet’s geology and climate and searching for signs of ancient life.
What lies beneath. The rover’s subsurface radar experiment, co-led by UCLA’s David Paige, has returned images showing unexpected variations in rock layers beneath the Jezero crater.
Probing the past. The variations could indicate past lava flows or possibly a river delta even older than the one currently being explored on the crater floor.
After a tantalizing year-and-a-half wait since NASA’s Mars Perseverance rover touched down on our nearest planetary neighbor, new data is arriving — and bringing with it a few surprises.
The rover, which is about the size of car and carries seven scientific instruments, has been probing Mars’ 30-mile-wide Jezero crater, once the site of a lake and an ideal spot to search for evidence of ancient life and information about the planet’s geological and climatic past.
Rendering of Perseverance, whose RIMFAX technology is exploring what lies beneath the Martian surface. Photo: NASA/JPL/Caltech/FFI
In a paper published today in the journal Science Advances, a research team led by UCLA and the University of Oslo reveals that rock layers beneath the crater’s floor, observed by the rover’s ground-penetrating radar instrument, are unexpectedly inclined. The slopes, thicknesses and shapes of the inclined sections suggest they were either formed by slowly cooling lava or deposited as sediments in the former lake.
Perseverance is currently exploring a delta on the western edge of the crater, where a river once fed the lake, leaving behind a large deposit of dirt and rocks it picked up along its course. As the rover gathers more data, the researchers hope to clear up the complex history of this part of the Red Planet.
“We were quite surprised to find rocks stacked up at an inclined angle,” said David Paige, a UCLA professor of Earth, planetary and space sciences and one of the lead researchers on the Radar Imager for Mars Subsurface Experiment, or RIMFAX. “We were expecting to see horizontal rocks on the crater floor. The fact that they are tilted like this requires a more complex geologic history. They could have been formed when molten rock rose up towards the surface, or, alternatively, they could represent an older delta deposit buried in the crater floor.”
Paige said that most of the evidence gathered by the rover so far points to an igneous, or molten, origin, but based on the RIMFAX data, he and the team can’t yet say for certain how the inclined layers formed. RIMFAX obtains a picture of underground features by sending bursts of radar waves below the surface, which are reflected by rock layers and other obstacles. The shapes, densities, thicknesses, angles and compositions of underground objects affect how the radar waves bounce back, creating a visual image of what lies beneath.
During Perseverance’s initial 3-kilometer traverse, the instrument has obtained a continuous radar image that reveals the electromagnetic properties and bedrock stratigraphy — the arrangement of rock layers — of Jezero’s floor to depths of 15 meters, or about 49 feet. The image reveals the presence of ubiquitous layered rock strata, including those that are inclined at up to 15 degrees. Compounding the mystery, within those inclined areas are some perplexing highly reflective rock layers that in fact tilt in multiple directions.
“RIMFAX is giving us a view of Mars stratigraphy similar to what you can see on Earth in highway road cuts, where tall stacks of rock layers are sometimes visible in a mountainside as you drive by,” Paige explained. “Before Perseverance landed, there were many hypotheses about the exact nature and origin of the crater floor materials. We’ve now been able to narrow down the range of possibilities, but the data we’ve acquired so far suggest that the history of the crater floor may be quite a bit more complicated than we had anticipated.”
The data collected by RIMFAX will provide valuable context to rock samples Perseverance is collecting, which will eventually be brought back to Earth.
“RIMFAX is giving us the backstory of the samples we’re going to analyze. It’s exciting that the rover’s instruments are producing data and we’re starting to learn, but there’s a lot more to come,” Paige said. “We landed on the crater floor, but now we’re driving up on the actual delta, which is the main target of the mission. This is just the beginning of what we’ll hopefully soon know about Mars.”
The paper, “Ground penetrating radar observations of subsurface structures in the floor of Jezero crater, Mars,” is one of three simultaneously published papers discussing some of the first data from Perseverance.
Finding water on the Moon could be easier with a Goddard technology that uses an effect called quantum tunneling to generate a high-powered terahertz laser, filling a gap in existing laser technology.
Locating water and other resources is a NASA priority crucial to exploring Earth’s natural satellite and other objects in the solar system and beyond. Previous experiments inferred, then confirmed the existence of small amounts of water across the Moon. However, most technologies do not distinguish among water, free hydrogen ions, and hydroxyl, as the broadband detectors used cannot distinguish between the different volatiles.
Goddard engineer Dr. Berhanu Bulcha said a type of instrument called a heterodyne spectrometer could zoom in on particular frequencies to definitively identify and locate water sources on the Moon. It would need a stable, high-powered, terahertz laser, which was prototyped in collaboration with Longwave Photonics through NASA’s Small Business Innovation Research (SBIR) program.
“This laser allows us to open a new window to study this frequency spectrum,” he said. “Other missions found hydration on the Moon, but that could indicate hydroxyl or water. If it’s water, where did it come from? Is it indigenous to the formation of the Moon, or did it arrive later by comet impacts? How much water is there? We need to answer these questions because water is critical for survival and can be used to make fuel for further exploration.”
As the name implies, spectrometers detect spectra or wavelengths of light in order to reveal the chemical properties of matter that light has touched. Most spectrometers tend to operate across broad sections of the spectrum. Heterodyne instruments dial in to very specific light frequencies such as infrared or terahertz. Hydrogen-containing compounds like water emit photons in the terahertz frequency range — 2 trillion to 10 trillion cycles per second — between microwave and infrared.
Like a microscope for subtle differences within a bandwidth like terahertz, heterodyne spectrometers combine a local laser source with incoming light. Measuring the difference between the laser source and the combined wavelength provides accurate readings between sub-bandwidths of the spectrum.
Traditional lasers generate light by exciting an electron within an atom’s outer shell, which then emits a single photon as it transitions, or returns to its resting energy level. Different atoms produce different frequencies of light based on the fixed amount of energy it takes to excite one electron. However, lasers fall short in a particular portion of the spectrum between infrared and microwave known as the terahertz gap.
“The problem with existing laser technology,” Dr. Bulcha said, “is that no materials have the right properties to produce a terahertz wave.”
This tiny laser capitalizes on quantum-scale effects of materials just tens of atoms across to generate a high-powered beam in a portion of the spectrum where traditional lasers fade in strength/NASA/Michael Giunto
Electromagnetic oscillators like those that generate radio or microwave frequencies produce low-powered terahertz pulses by using a series of amplifiers and frequency multipliers to extend the signal into the terahertz range. However, this process consumes a lot of voltage, and the materials used to amplify and multiply the pulse have limited efficiency. This means they lose power as they approach the terahertz frequencies.
From the other side of the terahertz gap, optical lasers pump energy into a gas to generate photons. However, high-powered, terahertz-band lasers are large, power hungry, and not suitable for space exploration purposes where mass and power are limited, particularly hand-held or Small Satellite applications. The power of the pulse also drops as optical lasers push towards the terahertz bandwidths.
To fill that gap, Dr. Bulcha’s team is developing quantum cascade lasers that produce photons from each electron transition event by taking advantage of some unique, quantum-scale physics of materials layered just a few atoms thick.
In these materials, a laser emits photons in a specific frequency determined by the thickness of alternating layers of semiconductors rather than the elements in the material. In quantum physics, the thin layers increase the chance that a photon can then tunnel through to the next layer instead of bouncing off the barrier. Once there, it excites additional photons. Using a generator material with 80 to 100 layers, totaling less than 10 to 15 microns thick, the team’s source creates a cascade of terahertz-energy photons.
This cascade consumes less voltage to generate a stable, high-powered light. One drawback of this technology is its beam spreads out in a large angle, dissipating quickly over short distances. Using innovative technology supported by Goddard’s Internal Research and Development (IRAD) funding, Dr. Bulcha and his team integrated the laser on a waveguide with a thin optical antenna to tighten the beam. The integrated laser and waveguide unit reduces this dissipation by 50% in a package smaller than a quarter.
He hopes to continue the work to make a flight-ready laser for NASA’s Artemis program.
The laser’s low size and power consumption allow it to fit in a 1U CubeSat, about the size of a teapot, along with the spectrometer hardware, processor, and power supply. It could also power a handheld device for use by future explorers on the Moon, Mars, and beyond.
