National Aeronautics and Space Administration
Volume 18
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Issue 1
Fall 2021
cuttingedge • goddard’s emerging technologies
Volume 18 • Issue 1 • Fall 2021
Lasers in Space Exploration:
Remote Sensing, Communications, Spectroscopy, and Detecting the Largest Collisions in the Cosmos Space lasers have their work cut out for them. From their invention at Hughes Research Lab in 1960, the utility of amplified light in a coherent wave form has changed the way NASA measures Earth’s ice caps, gravitational field and forests, advanced our communication capabilities and revolutionized chemical analysis. New laser applications under development will further enable NASA’s mission to explore worlds beyond our own, and Goddard will be right there at the forefront. The prototype laser delivered to the ESA this spring will help advance the fledgling field of gravitational wave observations. Meanwhile, the ultraviolet laser being developed to power the Dragonfly Mass
in this issue:
Fall 2021
Spectrometer (DraMS) instrument will help unravel the chemistry of Saturn’s moon, Titan. The Space Laser Assembly Cleanroom and Goddard’s Internal Research and Development program played a significant role in lighting the way for these laser technologies. This issue shows how Goddard is supporting these and other strategic laser technology developments. We’ll also provide a peak into the artificial intelligence work to help explore ocean worlds and some of the stellar CubeSat solutions that will help us study our Sun and Moon. v
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Lasers in space Exploration
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NASA Provides Laser for LISA Mission
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Goddard Lab an Ideal Nursery for Lasers to Probe the Mysteries of the Cosmos
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Small Satellite, Big Questions: CuPID CubeSat Provides New Perspectives on the Sun-Earth Boundary
10 Lunar IceCube to Detect Water on the Moon 12 Goddard Scientists Teach Algorithms to Detect Patterns in Data for Future Ocean World Studies 14 Converting Microwave Signals to Optics-on-a-Chip Makes for Light, Cool Instruments 15 Ultrafast Lasers Could Increase Accuracy of Mass Spectrometry
About the Cover The LISA Pathfinder spacecraft boosts to a higher apogee during maneuvers performed after launch in 2015. Goddard technologists delivered the first laser to the European Space Agency for testing for the LISA Mission to detect gravitational waves from massive collisions in the cosmos. At Goddard, the Space Laser Assembly Cleanroom provides a center of expertise for the art and science of building lasers for advanced instruments to explore exotic and extreme environments. In addition to LISA, SLAC will provide the ultraviolet lasers for the Dragonfly mission to Saturn’s moon Titan. (Image Credit: ESA/ATG Medialab)
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NASA Provides Laser for LISA Mission Finding the biggest collisions in the universe takes time, patience, and super steady lasers.
Photo Credit: Reto Duriet/CSEM
In May, NASA specialists working with industry partners delivered the first prototype laser for the European Space Agency-led Laser Interferometer Space Antenna, or LISA, mission. This unique laser instrument is designed to detect the telltale ripples in gravitational fields caused by the mergers of neutron stars, black holes, and supermassive black holes in space. Anthony Yu at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, leads the laser transmitter development for LISA. “We’ve developed a highly stable The first prototype of a laser sits on a testbed at the Swiss Center for Electronics and Microtechnology and robust laser for the LISA (CSEM), headquartered in Neuchâtel, Switzerland. CSEM will test and characterize the laser, which will be used to conduct gravitational wave experiments in space for the LISA mission observatory,” Yu said. “We leveraged lessons learned from previformation, with 1.5 million miles (2.5 million kilomeous missions and the latest technologies in photonters) separating each one. Each spacecraft will conics packaging and reliability engineering. Now, to tinuously point two lasers at its counterparts. The meet the challenging LISA requirements, NASA has laser receiver must be sensitive to a few hundreds developed a system that produces a laser transof picowatts of signal strength, as the laser beam mitter by using a low-power laser enhanced by a will spread to about 12 miles (20 kilometers) by the fiber-optic amplifier.” time it reaches its target spacecraft. A time-code The team is building upon the laser technology signal embedded in the beams allows LISA used in NASA’s Gravity Recovery and Climate to measure the slightest interference in these Experiment, or GRACE, mission. “We developed transmissions. a more compact version as a master oscillator,” Yu Ripples in the fabric of space-time as small as a said. “It has much smaller size, weight, and power picometer – 50 times smaller than a hydrogen atom consumption to allow for a fully redundant master – will produce a detectable change in the distances oscillator for long-duration lifetime requirements.” between the spacecraft. Measuring these changes The LISA laser prototype is a 2-watt laser operating will give scientists the general scale of what collided in the near-infrared part of the spectrum. “Our laser to produce these ripples and an idea of where in is about 400 times more powerful than the typithe sky to aim other observatories looking for cal laser pointer that puts out about 5 milliwatts or secondary effects. less,” Yu said. “The laser module size, not including These gravitational wave fluctuations are so small the electronics, is about half the volume of a typical they would be obscured by external forces such as shoe box.” dust impacts and the radiation pressure of sunThe Swiss Center for Electronics and Microtechnollight on the spacecraft. To mitigate this, the dragogy (CSEM), headquartered in Neuchâtel, Switzerfree control concept – demonstrated on the LISA land, confirmed receipt of the lasers and will begin Pathfinder mission in 2015 – uses free-floating test testing them for stability. masses sheltered inside each spacecraft as referLISA will consist of three spacecraft following Earth ence points for the measurement. in its orbit around the Sun and flying in a precision www.nasa.gov/gsfctechnology
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cuttingedge • goddard’s emerging technologies
Volume 18 • Issue 1 • Fall 2021
cuttingedge • goddard’s emerging technologies
Volume 18 • Issue 1 • Fall 2021
Image credit: European Southern Observatory/L. Calçada
This Artist’s impression shows an exotic binary system consisting of two stellar remnants, a white dwarf and a pulsar, orbiting each other. Symmetrical jets of radio waves emanate from the pulsar, and their close orbit produces gravitational waves – disturbances to the structure of spacetime.
LISA expands on work by the National Science Foundation’s Laser Interferometer GravitationalWave Observatory (LIGO), which captured its first recording of gravitational waves in 2015. Since then, the pair of ground-based observatories in Hanford, Washington, and Livingston, Louisiana, have captured four dozen mergers. Thomas Hams, program scientist for LISA at NASA Headquarters in Washington , said the precision laser measurements will allow us to zoom in on the gravitational wave signatures of these mergers and enable other observatories to focus on the right part of the sky to capture these events in the electromagnetic spectrum. NASA’s Fermi Gamma-ray Space Telescope picked up the first such multimessenger observation just seconds after LIGO detected a merger of two neutron stars through gravitational waves. “With LISA, the hope is you will be able to see these things develop before the merger actually happens,” Hams said. “There will be an indicator that something is coming.”
IRAD Heritage From early work simulating the physics of black hole mergers, through developing the laser interferometers to measure Earth’s gravitational field and enable the ESA’s LISA Pathfinder mission, Goddard’s Internal Research and Development program played a significant role in lighting the way for the LISA laser technology.
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Goddard’s then-Chief of the Gravitational Astrophysics Laboratory, Joan Centrella, used IRAD to develop computer models showing what to look for when black holes merge back in 2006 (Tech Trends, Spring 2006, Page 2). In 2012 and 2013, Babak Saif and his team continued to refine atom interferometry technology technology – which can detect picometer-level movements in a single atom – proven on the Gravity Recovery and Climate Experiment (Grace). Using IRAD funding, they adapted atom optics-based gravity gradiometer technology developed under Defense Advanced Research Projects (DARPA) funding, along with military and commercial partners (CuttingEdge, Fall 2013, Page 6). Centrella and others at Goddard depended on IRAD and other funding sources to continue refining the concepts and representing NASA on international gravitational-wave science Teams. In 2016, the successful Lisa Pathfinder and LIGO detections renewed interest in the Goddard team’s work (CuttingEdge, Fall 2016, Page 8), building momentum towards this year’s contribution to LISA.
Industry Partnership To achieve the required stability, the team brought Fibertek Inc. in Herndon, Virginia, and Avo Photonics Inc. in Horsham, Pennsylvania, to develop the laser, oscillator, and power amplifier, as well as an independent optical engineer in San Jose, California, to help verify the overall quality.
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Avo Photonics built the laser for the observatory. “Here you have the challenges of spaceborne ruggedness needs, on top of submicron-level optical alignment tolerance requirements. These really push your optical, thermal, and mechanical design chops,” Avo Photonics President Joseph L. Dallas said. “In addition, the narrow linewidth, low noise, and overall stability needed for this mission is unprecedented.” Photonics pioneer Tom Kane invented the monolithic laser oscillator technology that Goddard used to stabilize the frequency of the laser light. “Your average laser can be very messy,” Kane said. “They can wander all around their target frequency. You need a ‘quiet’ laser that’s exactly one wavelength and a perfect beam out to 15 decimal places of accuracy.” His oscillator technology uses feedback loops to keep the laser burning at such precision. “The wavelength ends up becoming the ruler for these incredible distances,” Kane said.
The high-power, low-noise amplifier came from Fibertek. Fibertek also contributed to NASA’s Ice Cloud and Land Elevation Satellite (ICESat) 2 and the CloudAerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), which has been operating a laser pointed at Earth for 15 years. Including time for testing on the ground and potential mission extensions, LISA’s lasers must operate without skipping a hertz for up to 16 years, Goddard’s Yu said. “Once launched, they will need to be in 24/7 operation for five years for the initial mission, with a possible six to seven years of extended mission after that,” Yu explained. “We need them to be stable and quiet.” v CONTACT Anthony.W.Yu@NASA.gov or 301-614-6248
Goddard Lab an Ideal Nursery for Lasers to Probe the Mysteries of the Cosmos Photo credits: NASA/Matt Mullin
At Goddard’s Space Laser Assembly Cleanroom (SLAC), the Laser and Electro-Optics Branch is building lasers for NASA’s Dragonfly mission to Saturn’s moon Titan and the European Space Agency’s (ESA) Laser Interferometer Space Antenna (LISA), which will measure waves in space-time caused by massive collisions. Goddard’s SLAC is a center of expertise for the art and science of building lasers for advanced instruments to explore exotic and extreme environments, including those that will be investigated by Dragonfly and LISA, both of which were developed with the help of Goddard Internal Research and Development, or IRAD funding. Lasers are difficult — they don’t “want” to work, Goddard Physicist Barry Coyle said. “Everything has to perfect. It’s like you’re balancing an egg on its end; it always wants to not work. You’re harnessing photons (particles of light) to do what you want — that’s very hard.” That’s why assembling them in one place is so critical to efficiency in production and cost. This is the
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This is the SLAC thermal vacuum chamber used to conduct environmental testing on space-flight class laser systems. The ICESAT-2 and GEDI lidar mission made use of this chamber for qualification and risk reduction testing. The flight and engineering model Dragonfly Mass Spectrometer (DraMS) Lasers as well as the engineering model LISA laser will be tested in the SLAC.
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idea behind the SLAC, which was conceived shortly after ICESat-1’s launch. ICESat-1 housed the Geoscience Laser Altimeter System, produced at a joint University of Maryland and Goddard facility. Although the laser worked well, Coyle said, producing space-flight laser systems outside of NASA could be expensive and inefficient. Pamela Millar, head of the Earth Science Technology Office, was the Remote Sensing branch head at the time and lead the effort to secure the funding for the SLAC, Coyle said. Ever since, the lab has been churning out lasers.
Photo credits: NASA/Matt Mullin
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Volume 18 • Issue 1 • Fall 2021
Exploring Strange Worlds
This is the Dragonfly Mass Spectrometer (DraMS) Laser: THANOS (Throttled Hydrocarbon Analysis Currently, the Goddard team is by Nanosecond Optical Source) engineering model. This laser is a NASA Goddard Code 554 indeveloping an ultraviolet (UV) laser house design that is currently being built and tested in the SLAC optical lab space. in the SLAC — the Dragonfly Mass Spectrometer (DraMS) laser — to help unravel the to solve a lot of the mysteries involved with this resecrets of Titan’s chemistry. The mission involves a ally interesting moon following on previous explorarotorcraft lander designed for multiple stops across tion, and to see if this moon could potentially harbor the surface of Titan. The lander, being designed any form of life would be very interesting.” and built at the Johns Hopkins Applied Physics Mullin said working on Dragonfly and with the team Laboratory in Laurel, Maryland, will carry a full suite has been amazing. of instruments to sample materials and develop “The real pleasure and the exciting part has been further knowledge of the moon’s surface composiworking with some of the best engineers and tion and other properties. scientists in the world on this project,” Mullin said. “I DraMS development began at Goddard in 2018 remember watching the Discovery Channel about with Dragonfly Phase A funding to develop an early future exploration to outer moons like Europa or prototype or brassboard. In 2019, Goddard scientist Titan, but I never really imagined that I’d be on one George Shaw won IRAD grants to design the engiof the teams helping explore it.” neering test unit and began fabricating components The extremely cold temperatures and methane in to build the unit. Goddard laser engineer Matt MulTitan’s atmosphere and on its surface pose addilin is continuing development work on the DraMS tional obstacles to exploration, Coyle said. It is critilaser in the SLAC. cal that the instrument is as small as possible and “Basically, the UV laser beam will be focused down that the weight and energy consumption is miniinto a sample cup, which holds some of Titan’s mized. Not to mention the fussy nature of lasers. surface materials,” he said. “The beam will desorb This is where the SLAC helps. Without SLAC, molecular compounds from the sample and excite producing the laser would involve a lot of moving ions (atoms and molecules with a net electric between buildings with separate teams working on it. charge) to be ingested into the mass spectrometer, which the scientists can use to detect what that “It helps having a central location where we can do sample is comprised of.” the optics bonding, the cleaning assembly, all the
The laser is exciting because it is flying on a New Frontiers mission, Mullin said. The New Frontiers program is a NASA initiative to fund missions that will explore parts of the solar system considered high priorities in planetary science. “We’ve sent a probe to Titan in the past,” Mullin said, “This instrument and this mission is destined PAGE 6
infrastructure here — it’s great,” Coyle said.
Probing Cosmic Mysteries The SLAC will also house the effort to build the lasers that LISA will use to detect the tiniest ripples in space time between three observatories flying
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in a precision formation (see related story, page 2). LISA will be the first space-based observatory of the space-time ripples called gravitational waves, which are generated by extremely violent events like black hole collisions. “The SLAC is a perfect place for us to build the LISA lasers,” said Anthony Yu, product development lead for the LISA laser. “The LISA lasers have many stringent requirements and we need to set up in-situ test stations to verify the laser performance during the build process. The SLAC allows us to set up specialized test stations for testing the laser in real-time, and also when it undergoes thermal vacuum cycling tests after it is assembled.” Paul Stysley, Goddard’s associate branch head of
laser and electro-optics, and product development lead for the DraMS laser, said the heart and soul of SLAC is in the way it streamlines the technology development and production of lasers. “What makes the SLAC unique is having a centralized location to develop, build and test space-flight laser systems,” Stysley said. “A product flow and infrastructure are in place to develop, environmentally test, and monitor a laser design from cradle to grave for a space-flight mission. This leads to significant reductions of technical risk and cost.” v CONTACT Matthew.W.Mullin@nasa.gov or 301-286-5021
Small Satellite, Big Questions: CuPID CubeSat Provides New Perspectives on the Sun-Earth Boundary One of the CubeSats launched with NASA and the U.S. Geological Survey’s Landsat 9 last month, the Cusp Plasma Imaging Detector, or CuPID is a small spacecraft with a big job. No larger than a loaf of bread nor heavier than a watermelon, CuPID will orbit about 340 miles (550 kilometers) above Earth’s surface. From there, CuPID will image the boundary where Earth’s magnetic field interacts with the Sun’s. Produced by Earth’s magnetic field, the magnetosphere is a protective bubble surrounding our planet, said Brian Walsh, assistant professor of Mechanical Engineering at Boston University and CuPID’s principal investigator. “Most of the time, we’re shielded pretty well from the Sun’s activity, as energy and particles from the Sun go around the Earth.” When the Sun gets active, though, its magnetic field can fuse with the Earth’s in a process called magnetic reconnection. Earth’s magnetosphere changes shape and solar radiation and energy comes pouring inward toward us, potentially putting satellites and astronauts in harm’s way. “With CuPID, we want to know what the boundary of Earth’s magnetic field looks like, and understand how and why energy sometimes gets in,” Walsh said. Emil Atz, a PhD candidate in Mechanical Engineering at Boston University teamed up with collaborators from Goddard, Boston University, Drexel University, Johns Hopkins University, Merrimack College, Aerospace Corporation, and University of www.nasa.gov/gsfctechnology
Photo credit: NASA/Chris Gunn
NASA scientists Michael Collier, David Sibeck, and Scott Porter teamed to develop and demonstrate the first wide-field X-ray camera for studying a poorly understood phenomenon called “charge exchange.”
Alaska, Fairbanks to make CuPID possible. While missions like NASA’s Magnetospheric Multiscale, or MMS, mission fly through magnetic
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reconnection events to see them at a micro scale, CuPID seeks a macro view. Using a wide field-ofview soft X-ray camera, CuPID observes lower-energy, or “soft,” X-rays emitted when solar particles collide with atoms in Earth’s outer atmosphere.
In December of 2015, a predecessor of CuPID flew on a second sounding rocket flight. Soon after, the project was selected by NASA to bring the full satellite with avionics to fruition. Students and scientists have been working on CuPID ever since.
Building that camera wasn’t easy. X-rays don’t bend as easily as visible light, so they can’t be focused with a traditional lens. Plus, imaging Earth’s magnetic boundary while orbiting Earth is like sitting in the front row of a movie theater – so close, it’s difficult to see the full picture. A suitable camera needs to be specially built to capture a wide field of view from relatively close.
“The original goal of CubeSats was to be lower cost, allowing the democratization of space,” said Collier. Lower costs mean more room for experimentation and innovation.
Sixteen years ago, a team of scientists, engineers, technicians and students at Goddard and Wallops Flight Facility on Wallops Island, Virginia began work on a prototype. Instead of bending the light, their camera reflected or “bounced” the X-rays into focus, passing them through a grid of tightly-packed channels arranged to give it a wide-field view. The camera, based on the same principles lobsters use to sense their environs, is named the ‘Lobster-eye’ camera. In December of 2012, Dr. Michael R. Collier, who led the Goddard contribution to CuPID, and Goddard colleagues Dr. David G. Sibeck and Dr. F. Scott Porter, tested the camera in space for the first time aboard the DXL sounding rocket. “It was so successful that we immediately started working on ways to miniaturize it and put it into a CubeSat,” Collier said.
“They’re higher risk, but also higher reward,” Walsh said. The project received early development funding from Goddard’s Internal Research and Development, or IRAD, program before being picked up by NASA’s Heliophysics Technology and Instrument Development for Science, or H-TIDeS initiative (see CuttingEdge Winter 2016, Page 10).
The Journey Just Ahead When you help build a satellite the size of a shoebox, you learn pretty much everything about it, Atz said. You learn how to write a proposal to fund it, how to place the screws that hold it together, how to test each instrument to ensure it functions properly. And then you learn how to say goodbye. “It’s a scary feeling, working on a piece of hardware full-time for four years, and then putting it into the rocket deployer to never see it again,” Atz said. “I didn’t want to close the door.”
A photo of CuPID in December 2019, when the chassis, or base frame of the device, met the avionics.
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Photo Cedit: Emil Atz
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Photo credit: Brian Walsh
Emil Atz and Kenneth M Simms, engineer at NASA’s Goddard Space Flight Center, wiring elements of the CuPID spacecraft — short for Cusp Plasma Imaging Detector — in January 2020 at Goddard.
Now his team is preparing to receive CuPID’s data on the mysteries of magnetic reconnection. Atz says he is eager to make first contact with the satellite once it’s in space and to start transferring data. Students will be involved with that, too, including Boston University mechanical engineering student Jacqueline Bachrach. “I’ve learned a lot of important skills, which I may eventually apply to other missions,” said Bachrach, who enrolled in Walsh’s Introduction to Rocketry course last year. “Everyone on the project has so much knowledge that they’re willing to share. It’s been an incredibly valuable experience, especially for an undergrad.” “With a big mission, you don’t get a lot of opportunities for students to have a heavy hand in contributing,” Atz said. “With CuPID, students have been involved almost every step of the way.” Atz and Walsh have begun training several undergraduate students, including Bachrach, to track the satellite’s health and interpret its data from orbit. For the many students and scientists involved in CuPID’s more than 15 years of development, the most exciting part is yet to come.
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And the Journey Still Farther Beyond CuPID sets the scene for a host of future X-ray missions said Goddard researcher David Sibeck. Walsh is already preparing a soft X-ray camera called Lunar Environment heliospheric X-ray Imager (LEXI) to look back on the Earth’s magnetosphere from the lunar surface in 2023. Led by Sibeck, Collier, and Porter at Goddard, the team is now working on a NASA Medium Explorer mission concept called Solar-Terrestrial Observer for the Response of the Magnetosphere (STORM) that builds on CuPID’s legacy. STORM is a multiinstrument mission that would track the flow of solar wind energy into and through the magnetosphere by taking its own solar wind measurements and imaging the magnetopause, aurora, and charged particles in near-Earth space. If selected, it would be launched in 2026 into a giant circular polar orbit with a radius halfway to the Moon. In addition, Sibeck said team members have already begun to think about X-ray missions to other planets, like Venus or Mars. v CONTACTS BWalsh@BU.edu or 978.505.7343 Michael.R.Collier@nasa.gov or 301.286.5256 Frederick.S.Porter@nasa.gov or 301.286.5016 David.G.Sibeck@nasa.gov or 301.286.5998
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Lunar IceCube to Detect Water on the Moon Putting humans in space requires packing everything they need to survive aboard the spacecraft: food, water, clothing, even air to breathe. Using resources found on other planets can bring crewed missions within reach. NASA is now on a quest to identify water and other resources that can benefit the upcoming Artemis missions. “The Lunar IceCube is a CubeSat that will orbit the Moon searching for signs of water ice on the lunar surface that may be useful for Artemis and future exploration missions,” said Terry Hurford, instrument scientist for Lunar IceCube’s near-infrared point spectrometer. “If you were to send a crewed mission there, they would need drinking water, but water can also be used as a fuel source when broken down into hydrogen and oxygen.”
Photo credit: NASA/Mark Lupisella
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LunarIceCube, which fits in a package as big as a briefcase, will do big science finding molecular water on the Moon.
A second goal of the mission is to understand the water dynamics on the Moon, which can provide insight into the Moon’s origin.
four microns — to identify different compounds on the Moon. Water can be identified at wavelengths around three microns.
Lunar IceCube has been integrated as a secondary payload of the Space Launch System (SLS), which will launch later this year on the Artemis I mission.
The BIRCHES instrument, roughly the size of an eight-inch tissue box, occupies about one-third of the volume of Lunar IceCube. The team had to drastically miniaturize legacy hardware from OSIRIS-REx to approximately one-sixth of its original size. In addition to BIRCHES, the briefcasesized satellite contains a power system, propulsion system, and communications system.
This CubeSat will build upon NASA’s previous investigations into water on the Moon. The Stratospheric Observatory for Infrared Astronomy (SOFIA) detected, for the first time, water molecules on a sunlit portion of the Moon, NASA announced in October of last year. Following previous observations of hydrogen on the lunar surface, this discovery confirmed water’s existence on the Moon. Two years before SOFIA’s detection, NASA’s Moon Mineralogy Mapper (M3) instrument, aboard the Indian Space Research Organization’s Chandrayaan-1 spacecraft, identified evidence of water ice at the Moon’s poles by measuring reflection and absorption properties. The Broadband InfraRed Compact High-resolution Explorer Spectrometer (BIRCHES), built at NASA’s Goddard Space Flight Center for Lunar IceCube, will continue to refine our understanding of water resources on the Moon. BIRCHES breaks down near-infrared light — wavelengths between one and PAGE 10
The CubeSat dispenser on the Orion stage adapter limited the size of the spacecraft, and thus the BIRCHES instrument. “We were trying to create a very small instrument and squeeze it inside of a very small spacecraft,” said Goddard’s Lunar IceCube Manager Mark Lupisella. BIRCHES needs to reach a very cold temperature, which, when combined with its small size packed inside a small spacecraft, makes for unique thermal management challenges. A deployable copper radiator will flip up after the spacecraft is deployed. “It’s a fairly elegant solution to help provide a lowmass, low-volume radiative surface that helps get
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the instrument temperature down,” Lupisella said. Thermal vacuum tests were performed in Goddard facilities. Lunar IceCube will enter a more generic orbit called near-rectilinear halo orbit (NRHO) for around 200 days after the SLS launch, before taking a 120day transit to the science orbit. Using NRHO helps address the trajectory challenges that come with changing launch and deployment dates. “This trajectory accommodates a smaller spacecraft that doesn’t have much space for fuel,” Lupisella said. “It allows us to use less fuel and reduce cost.”
“The Lunar IceCube spacecraft will deploy after the SLS launch while still relatively close to Earth,” Hurford said. “Missions beyond low-Earth orbit are more challenging. Lunar IceCube has incorporated an innovative propulsion system designed to get it into lunar orbit.”
Photo Courtesy: Terry Hurford
Small satellites, including CubeSats like Lunar IceCube, provide a low-cost platform for scientific research, technology demonstrations, and educational investigations. NASA’s small satellite initiatives develop missions to observe Earth, study the Moon, and test advanced instruments like BIRCHES.
Terry Hurford holds a 3D printed real-size model of the Lunar IceCube CubeSat which will launch for the Moon in a few months.
Once deployed, Lunar IceCube makes its own way to the Moon, using low-thrust ion engines. Lunar flybys also help shed enough velocity for the CubeSat to be captured in a lunar orbit. Once there, it will collect science data for up to six months. Lunar IceCube will travel in a high-inclination orbit, meaning it will fly closer to the Moon’s poles than its equator. The CubeSat will take observations as close as 62 miles (100 km) above the lunar surface and transmit data back to Earth while at its farthest point from the Moon, about 620 miles (1,000 km). The orbit allows the spacecraft to collect data primarily from higher latitudes where temperatures are colder, and only from the side illuminated by the Sun in order to detect infrared light reflected from the surface. Hurford said the compact instrument offers much potential for exploring the composition of other objects, such as near-Earth asteroids. www.nasa.gov/gsfctechnology
“It’s something even an astronaut could use,” Hurford said. “It’s small enough that a handheld version could be made for use on the Moon.” Lunar IceCube is funded by NASA’s Next Space Technologies for Exploration Partnerships program. Lunar IceCube will be tracked at the ground station at the Morehead State University in Kentucky, which manages the mission. Partners include NASA’s Goddard Space Flight Center in Greenbelt, Maryland; NASA’s Jet Propulsion Laboratory in Pasadena, California; NASA’s Katherine Johnson Independent Verification and Validation Facility in Fairmont, West Virginia; and Busek Space Propulsion and Systems in Natick, Massachusetts. v CONTACT Terry.A.Hurford@nasa.gov or 301-286-4249
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Goddard Scientists Teach Algorithms to Detect Patterns in Data for Future Ocean World Studies Probes sent to investigate ocean worlds like Saturn’s moon Enceladus and Jupiter’s Europa will collect vast amounts of data, and may need to make autonomous decisions in real time about what warrants a closer look. Dr. Bethany Theiling, an Early Career geoscientist at Goddard, hopes to solve the problem of big data as well as communications constraints that come with the territory of investigating planets millions of miles away. These probes will not be able to depend too much on the decision-making or data analysis of human controllers here on Earth.
worlds they hope to visit are much farther away than a Goddard laboratory, which creates the problem of communicating to the spacecraft with limited bandwidth. “The problem is the spacecraft are so far away that the actual data rates and latency are a big limiting factor in what the spacecraft can do.” said James MacKinnon, Goddard artificial intelligence and machine learning researcher.
To start, she simulates oceans of data in the lab. “When I go in the lab, I actually make other worlds there,” Theiling said. “I make oceans that we’ve never even been to. Then I try to figure out if we could determine what those oceans are actually made of and how hard that might be.”
An AI-powered probe, however, could conduct preliminary onboard analysis in order to prioritize transmission of the most important data back to Earth first. The spacecraft would decipher the collected data in real time, determining what specific data points should be sent back for further research, what aspects of that data can remain cached on the spacecraft, and where the spacecraft should turn its focus to learn more.
These oceans that Theiling and her team build in their lab are vital to the construction of algorithms that can detect, analyze, and define data. The real
This is where machine learning becomes useful. Theiling and MacKinnon are currently teaching machine learning algorithms how to decipher Photo credit: NASA/Rebecca Roth
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Bethany Theiling works with a mass spectrometer in her lab.
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and categorize traits using data from the worlds constructed in their lab, along with data Theiling brought with her from her time at the University of Tulsa and other large Earth science datasets. Once these data are prepared, the machine learning algorithm forms a neural network, making connections between the data and prioritizing certain traits, effectively training the machine. “We almost immediately got really interesting results,” MacKinnon said. “We saw these distinct clusters of points, and usually that’s a good indicator that there are patterns in that data.”
Theiling and MacKinnon aim to use their algorithm for ocean worlds like Europa and Enceladus, which have liquid oceans below their surface ice layers. The tidal forces of their host planets Jupiter and Saturn effect both of these ice moons, keeping their cores from freezing and causing liquid to vent above the surface from below. A spacecraft flying through the plume could collect samples and run them through a mass spectrometer for the algorithm to study. The machine learning process could decipher this data, informing about the ocean below it, ideally characterizing the possibility for life in that landscape.
Closer to Home This process of machine learning also applies to problems closer to home. “Climate change is incredibly important to me. And so, I’ve been hoping for a way that I can contribute to that science with the skill set that I have,” Theiling said. Theiling and MacKinnon ran preliminary tests for machine learning related to Earth studies using a database from the National Ecological Observatory Network, held by the National Science Foundation. This data represents levels of carbon dioxide from varying heights away from Earth’s surface, and from ecosystems all around the United States. “Understanding how things like carbon emissions can change is an important part of knowing the
Image credit: NASA/JPL/Bethany Theiling
These clusters, found on a visual map of possible data after processing, clearly visualize the unknowns as well. If the algorithm designates that data to an already defined cluster, the composition of the ocean world being studied is assumed to be similar to that of known oceans. However, if the algorithm places data in a spot that isn’t defined, it indicates those characteristics have never been discovered, an equally exciting possibility.
Bethany Theiling’s ocean worlds experiments mimic the possible future sampling of trace amounts of CO2 that scientists believe outgas from the interior of an ocean world and interact with the seawater and ice. Her machine learning efforts seek to find features in the data that can help identify seawater and ice composition.
problem exists, and then knowing how to fix it,” MacKinnon said. The research team aims to identify seasonal patterns, locational patterns, yearly patterns, and even the effects of feedback loops with the machine learning process. Streamlined processing of this data allows it to be used in a multifaceted manner, and it also gives insight to the adaptability of the algorithms. “How transferable is what we learned from the labcreated ‘worlds’ to a very complicated system like Earth that has plants, water, a hydrological system, and a biological system that’s changing everything?” Theiling asks. Her current Internal Research and Development (IRAD) grant enabled the purchase of the mass spectrometer and peripheral suites. With this equipment, and an additional grant through Fundamental Laboratory Research (FLaRe), they can continue their work in perfecting the algorithm to analyze and make decisions regarding data. (See profile: CuttingEdge, Summer 2021, Page 6) v CONTACT Bethany.P.Theiling@nasa.gov or 301-614-6909
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Converting Microwave Signals to Optics-on-a-Chip Makes for Light, Cool Instruments Sometimes innovators adapt proven technologies to enable new capabilities. A new instrument concept combines existing technologies and techniques to improve the way exploration spacecraft receive and convert radio frequency signals to data by converting the radio signal to optical for processing. Goddard Photonics Engineer Eleanya Onuma said electronic signal processing components used in communication and remote sensing applications are efficient but bulky due to their ruggedized packaging for the space environment. They also operate within a narrow bandwidth which limits science investigations. He plans to convert the long-wavelength microwave signals to more compact optical wavelengths using a miniaturized version of an electro-optic modulator. “Electro-optic modulators have cross-cutting applications in Goddard’s instrument designs,” Onuma said. “So why don’t we take a stab at that? How can we improve this essential electrooptic component to enable instrument miniaturization without sacrificing performance?”
Photo Courtesy: Eleanya Onuma
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Eleanya Onuma is building a prototype of his signal processing technology in a Goddard lab.
He plans to use microwave photonics technology to design an ultra-wide band electro-optic modulator for Photonics Integrated Circuits (PICs). By combing the multiple operations of a microwave front end receiver into a single chip, communication and remote sensing instruments can process incoming signals across broader bandwidths while reducing the overall size of the modulator, susceptibility to noise, and transmission losses. A modulator on a circuit board consists of a radio frequency switch, oscillator, mixer, low noise amplifier and frequency filters. Goddard Systems PAGE 14
Engineer Chris Green said these compact PICs will improve essential signal-processing for both communication and remote sensing applications in a single component without compromising performance. Onuma’s project received Center Innovation Funds, or CIF, last year to design and validate the performance of a new, compact electro-optical modulator. This year, the team is working on prototyping their design.
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“We are looking to broaden the frequency range of operation while being compatible with current integrated photonic platforms, which inherently allows for device miniaturization,” Onuma said. The design will eliminate the need for multiple antennas and electro-optic modulators in broadband applications. While the technology isn’t connected to a particular mission, the design allows for flexible integration with low-power PICs, Onuma said. Developing smaller, faster, and more cost-effective technology will optimize mission costs across the board. “Radiometers, for example, that observe the microwave range of the electromagnetic spectrum are essential for profiling atmospheric constituents of planetary bodies for molecules like water,” Onuma said. Remote sensing engineers typically optimize their instruments’ antennas and front-end electronics circuits for the specific frequency band of scien-
tific interest, Onuma said. This means an instrument may need multiple electro-optic modulators and signal processors to accommodate different frequency bands. Consequently, each additional component results in an increase in heat generation, size, weight and power demands on a spacecraft. Having a single component that can receive and modulate broadband frequencies of interest enables a wider collection of scientific data. Shrinking these critical components will allow future missions to operate at the same, if not better, capacity while meeting the size, weight and power demands of small satellite platforms, Onuma said. “Other applications include software-defined radios and broadband wireless communications for terrestrial and space applications,” he said. v CONTACT Eleanya.E.Onuma@nasa.gov or 301.286.1157
Ultrafast Lasers Could Increase Accuracy of Mass Spectrometry Researchers at Goddard believe lasers that can pulse as quickly as one quadrillionth of a second could considerably improve the science of mass spectrometry by providing more accurate readings. “The femtosecond laser has the advantage that you can achieve high peak power but the pulse width is so short, you don’t actually heat up your materials,” said Dr. Anthony Yu, co-investigator on this project. Mass spectrometer technology requires a material to be disintegrated into atom-sized particles, which are then funneled between two magnets that sort the atoms by weight. Where the atoms hit on the detector can reveal their exact mass and therefore their specific element. Yu is part of a Goddard engineering team led by Elisavet Troupaki that, collaborating with Goddard scientists led by Dr. Andrej Grubisic, is researching super-fast lasers that can precisely disassemble atoms from a solid material without heating or burning them. This will improve the accuracy of mass spectrometers. An optimal power must be reached in order to properly break down materials, Yu said. To increase power in a laser you can increase the energy of the laser or shorten the laser pulse. Peak power www.nasa.gov/gsfctechnology
and pulse width – or length of time – are inversely proportional, meaning as one of the two variables decrease, the other increases. Studies are also being completed using nanosecond lasers, which are powerful, but do not allow for accurate spectrometry uses. “When it goes into the nanosecond regime, although it sounds very short already, it is heating the material,” said Goddard engineer Steven Li. Heating can alter the material’s properties and reduce the precision of a cut, two things you do not want for mass spectrometry. Not only does the femtosecond laser’s extremely short duration ensure that the materials won’t be heated, but the shorter pulse width also allows for a cleaner, more precise cut. A femtosecond laser has a pulse duration of 10-15, or one quadrillionth of a second, compared to the 10-9, or one billionth of a second, for a nanosecond laser. “This high-powered, extremely fast laser requires specific materials in the design and construction, and optical fiber is currently the best for this application,” Li said. Optical fiber has a core width of a few
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microns, or about the size of the diameter of a strand of hair. A few meters of coiled fiber is compact but reliable. “Because everything is confined to fiber, there’s a low risk of anything being misaligned,” Yu said, “If you build a laser using larger optical components like mirrors and refractors, you have to align everything correctly. For fiber lasers, everything is spliced together, and that will make things a lot easier for space application.”
Photo courtesy: Anthony Yu
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The Goddard team A workbench at Goddard is mounted with lasers and fiber connectors to test femtosecond-pulse laser technology. under Troupaki, previously led by Molly Famissing, planetary science technology identified in hey, received Internal Research and Development the last decadal survey”. (IRAD) and Center Innovation Funding (CIF) grants for several years to explore the uses of ultrafast Ultrafast lasers also have applications in lasers. The research team is passionate about their work as well as the possible avenues it can take them in the future. “Existing instruments and concepts rely on nanosecond laser technology to enable laser desorption mass spectrometry LDMS,” said Project Scientist Dr. Grubisic. “The shorter pulse duration laser technology pursued here could dramatically enhance the analytical power of the LDMS due to its potential to minimize molecular fragmentation and sample fractionation. This improves sensitivity for fragile molecules, including potential molecular biomarkers that will continue to be of interest in astrobiology-focused planetary missions. It also opens the door to LDMS-based instruments for establishing the ages of rock formations – a key
space travel and communication
“We are looking at femtosecond lasers in particular” Yu said, “because the femtosecond laser can also be used for precision ranging. You have a series of pulses separated at a fixed period, and by detecting that series of pulses, you can actually have precision timing provided to you. For example, from Earth you can send that signal to a distant satellite, and when they receive it, they can use it for clock synchronization.” v CONTACT Elisavet.Troupaki-1@nasa.gov or 301-614-6119
CuttingEdge is published quarterly by the Office of the Chief Technologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The publication describes the emerging, potentially transformative technologies that Goddard is pursuing to help NASA achieve its missions. For more information about Goddard technology, visit the website listed below or contact Chief Technologist Peter Hughes, Peter.M.Hughes@nasa.gov. If you wish to be placed on the publication’s distribution list, contact Editor Karl Hille, Karl.B.Hille@nasa.gov. Contributors to this issue include: Alison Gold, Erica McNamee, Julie Freijat and Sarah Readdean. Publication Number: NP-2021-10-693-GSFC
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