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Next Generation Ion Engines Will Be Extremely Powerful
During the Space Race, scientists in both the United States and the Soviet Union investigated the concept of ion propulsion. Like many early Space Age proposals, the concept was originally explored by luminaries like Konstantin Tsiolkovsky and Hermann Oberth – two of the “forefathers of rocketry.” Since then, the technology has been validated repeatedly by missions like the Deep Space-1 (DS-1) technology demonstrator, the ESA’s Smart-1 lunar orbiter, JAXA’s Hayabusa and Hayabysa 2 satellites, and NASA’s Dawn mission.
Looking to the future of space exploration, researchers at the NASA Glenn Research Center (GRC) have been busy developing a next-generation ion engine that combines extreme fuel efficiency with high acceleration. These efforts have led to the NASA-H71M sub-kilowatt Hall-effect thruster, a small spacecraft electric propulsion (SSEP) system that will enable new types of planetary science missions. With the help of commercial partners like SpaceLogistics, this thruster will also be used to extend the lifetimes of spacecraft that are already in orbit.
Space exploration and commercial space have benefitted from the development of small spacecraft and small satellites. These missions are notable for being cost-effective since they require less propellant to launch, can be deployed in smarms, and take advantage of rideshares. Similarly, the proliferation of small satellite constellations in Low Earth Orbit (LEO) has made low-power Hall-effect thrusters the most common electric propulsion system in space today. These systems are noted for their fuel efficiency, allowing many years of orbital maneuvers, corrections, and collision avoidance.
Nevertheless, small spacecraft will need to be able to perform challenging propulsive maneuvers like achieving escape velocity, orbital capture, and other maneuvers that require significant acceleration (delta-v). The thrust required to perform these maneuvers – 8 km/s (~5 mps) of delta-v – is beyond the capability of current and commercially available propulsion technology. Moreover, low-cost commercial electric propulsion systems have limited lifetimes and typically process only about 10% of a small spacecraft’s propellant mass.
Similarly, secondary spacecraft are becoming more common thanks to rockets with excess capacity (enabling rideshare programs). Still, these are generally limited to scientific targets that align with the primary mission’s trajectory. Additionally, secondary missions typically have limited time to collect data during high-speed flybys. What is needed is an electric propulsion system that requires low power (sub-kilowatt) and has high-propellant throughout – meaning it is capable of using lots of propellant over its lifetime.
To meet this demand, engineers at NASA Glenn are taking many advanced high-power solar electric propulsion (SEP) elements developed over the past decade and are miniaturizing them. These elements were developed as part of NASA’s Moon to Mars mission architecture, with applications including the Power and Propulsion Element (PPE) of the Lunar Gateway. A SEP system was also part of the design for a Deep Space Transport (DST), the vehicle that will conduct the first crewed missions to Mars by 2040. The NASA-H71M system, however, is expected to have a major impact on small spacecraft, expanding mission profiles and durations.
According to NASA, missions using the NASA-H71M system could operate for 15,000 hours and process over 30% of the small spacecraft’s initial mass in propellant. This system could increase the reach of secondary spacecraft, allowing them to deviate from the primary mission’s trajectory and explore a wider range of scientific targets. By allowing spacecraft to decelerate and make orbital insertions, this technology could increase mission durations and the amount of time they have to study objects.
NASA-H71M Hall-effect thruster on the Glenn Research Center Vacuum Facility 8 thrust stand (left) and Dr. Jonathan Mackey tuning the thrust stand before closing and pumping down the test facility (right). Credit: NASA GRCIt’s also beyond the needs of most commercial LEO missions, and the associated costs are generally higher than what commercial missions call for. As such, NASA continues to seek partnerships with commercial developers working on small commercial spacecraft with more ambitious mission profiles. One such partner is SpaceLogistics, a wholly owned subsidiary of Northrop Grumman that provides in-orbit satellite servicing to geosynchronous satellite operators using its proprietary Mission Extension Vehicle (MEV).
This vehicle relies on Northrop Grumman NGHT-1X Hall-effect thrusters based on the NASA-H71M design. This propulsive capability will allow the MEV to reach satellites in Geosynchronous Earth Orbit (GEO), where it will dock with customer’s satellites, extending their lives for at least six years. Through a Space Act Agreement (SAA), Northrop Grumman is conducting long-duration wear tests (LDWT) at NASA Glenn’s Vacuum Facility 11. The first three MEP spacecraft are expected to launch in 2025 and extend the lives of three GEO communication satellites.
Further Reading: NASA
The post Next Generation Ion Engines Will Be Extremely Powerful appeared first on Universe Today.
Neutron Stars Could be Capturing Primordial Black Holes
The Milky Way has a missing pulsar problem in its core. Astronomers have tried to explain this for years. One of the more interesting ideas comes from a team of astronomers in Europe and invokes dark matter, neutron stars, and primordial black holes (PBHs).
Astronomer Roberto Caiozzo, of the International School for Advanced Studies in Trieste, Italy, led a group examining the missing pulsar problem. “We do not observe pulsars of any kind in this inner region (except for the magnetar PSR J1745-2900),” he wrote in an email. “This was thought to be due to technical limitations, but the observation of the magnetar seems to suggest otherwise.” That magnetar orbits Sagittarius A*, the black hole at the core of the Milky Way.
An x-ray map of the core of the Milky Way showing the position of the recently discovered magnetar orbiting the supermassive black hole Sgr A*. Courtesy Chandra and XMM-Newton.The team examined other possible reasons why pulsars don’t appear in the core and looked closely at matnetar formation as well as disruptions of neutron stars. One intriguing idea they examined was the cannibalization of primordial black holes by neutron stars. The team explored the missing-pulsar problem by asking the question: could neutron star-primordial black hole cannibalism explain the lack of detected millisecond pulsars in the core of the Milky Way? Let’s look at the main players in this mystery to understand if this could happen.
Neutron Stars, Pulsars, and Little Black Holes, Oh MyTheory suggests that primordial black holes were created in the first seconds after the Big Bang. “PBHs are not known to exist,” Caiozzo points out, “but they seem to explain some important astrophysical phenomena.” He pointed at the idea that supermassive black holes seemed to exist at very early times in the Universe and suggested that they could have been the seeds for these monsters. If there are PHBs out there, the upcoming Nancy Grace Roman Telescope could help find them. Astronomers predict they could exist in a range of masses, ranging from the mass of a pin to around 100,000 the mass of the Sun. There could be an intermediate range of them in the middle, the so-called “asteroid-mass” PBHs. Astronomers suggest these last ones as dark matter candidates.
Primordial black holes, if they exist, could have formed by the collapse of overdense regions in the very early universe. Credit M. Kawasaki, T.T. Yanagida.Dark matter makes up about 27 percent of the Universe, but beyond suggesting that PBH could be part of the dark matter content, astronomers still don’t know exactly what it is. There does seem to be a large amount of it in the core of our galaxy. However, it hasn’t been directly observed, so its presence is inferred. Is it bound up in those midrange PBHs? No one knows.
The third player in this missing pulsar mystery is neutron stars. They’re huge, quivering balls of neutrons left over after the death of a supergiant star of between 10 and 25 solar masses. Neutron stars start out very hot (in the range of ten million K) and cool down over time. They start out spinning very fast and they do generate magnetic fields. Some emit beams of radiation (usually in radio frequencies) and as they spin, those beams appear as “pulses” of emission. That earned them the nickname “pulsar”. Neutron stars with extremely powerful magnetic fields are termed “magnetars”.
Pulsars are fast-spinning neutron stars that emit narrow, sweeping beams of radio waves. A new study identifies the origin of those radio waves. NASA’s Goddard Space Flight Center The Missing Pulsar ProblemAstronomers have searched the core of the Milky Way for pulsars without much success. Survey after survey detected no radio pulsars within the inner 25 parsecs of the Galaxy’s core. Why is that? Caizzo and his co-authors suggested in their paper that magnetar formation and other disruptions of neutron stars that affect pulsar formation don’t exactly explain the absence of these objects in the galactic core. “Efficient magnetar formation could explain this (due to their shorter lifetime),” he said, “But there is no theoretical reason to expect this. Another possibility is that the pulsars are somehow disrupted in other ways.”
Usually, disruption happens in binary star systems where one star is more massive than the other and it explodes as a supernova. The other star may or may not explode. Something may kick it out of the system altogether. The surviving neutron star becomes a “disrupted” pulsar. They aren’t as easily observed, which could explain the lack of radio detections.
If the companion isn’t kicked out and later swells up, its matter gets sucked away by the neutron star. That spins up the neutron star and affects the magnetic field. If the second star remains in the system, it later explodes and becomes a neutron star. The result is a binary neutron star. This disruption may help explain why the galactic core seems to be devoid of pulsars.
Using Primordial Black Hole Capture to Explain Missing PulsarsCaizzo’s team decided to use two-dimensional models of millisecond pulsars—that is, pulsars spinning extremely fast—as a way to investigate the possibility of primordial black hole capture in the galactic core. The process works like this: a millisecond pulsar interacts in some way with a primordial black hole that has less than one stellar mass. Eventually, the neutron star (which has a strong enough gravitational pull to attract the PBH) captures the black hole. Once that happens, the PBH sinks to the core of the neutron star. Inside the core, the black hole begins to accrete matter from the neutron star. Eventually, all that’s left is a black hole with about the same mass as the original neutron star. If this occurs, that could help explain the lack of pulsars in the inner parsecs of the Milky Way.
Could this happen? The team investigated the possible rates of capture of PBHs by neutron stars. They also calculated the likelihood that a given neutron star would collapse and assessed the disruption rate of pulsars in the galactic core. If not all the disrupted pulsars are or were part of binary systems, then that leaves neutron star capture of PBHs as another way to explain the lack of pulsars in the core. But, does it happen in reality?
Missing Pulsar Tension ContinuesIt turns out that such cannibalism cannot explain the missing pulsar problem, according to Caizzo. “We found that in our current model PBHs are not able to disrupt these objects but this is only considering our simplified model of 2 body interactions,” he said. It doesn’t rule out the existence of PHBs, only that in specific instances, such capture isn’t happening.
So, what’s left to examine? If there are PHBs in the cores and they’re merging, no one’s seen them yet. But, the center of the Galaxy is a busy place. A lot of bodies crowd the central parsecs. You have to calculate the effects of all those objects interacting in such a small space. That “many-body dynamics” problem has to account for other interactions, as well as the dynamics and capture of PBHs.
Astronomers looking to use PBH-neutron star mergers to explain the lack of pulsar observations in the core of the Galaxy will need to better understand both the proposed observations and the larger populations of pulsars. The team suggests that future observations of old neutron stars close to Sgr A* could be very useful. They’d help set stronger limits on the number of PBHs in the core. In addition, it would be useful to get an idea of the masses of these PBHs, since those on the lower end (asteroid-mass types) could interact very differently.
For More InformationRevisiting Primordial Black Hole Capture by Neutron Stars
Searching for Pulsars in the Galactic Centre at 3 and 2 mm
The post Neutron Stars Could be Capturing Primordial Black Holes appeared first on Universe Today.
Watch 2 gorgeous supernova remnants evolve over 20 years (timelapse video)
NASA to Provide Coverage as Dragon Departs Station with Science
NASA and its international partners are set to receive scientific research samples and hardware as a SpaceX Dragon cargo spacecraft departs the International Space Station on Sunday, April 28 weather permitting.
The agency will provide coverage of undocking and departure beginning at 12:45 p.m. EDT on NASA+, NASA Television, the NASA app, YouTube, and the agency’s website. Learn how to stream NASA TV through a variety of platforms including social media.
Dragon will undock from the station’s zenith port of the Harmony module at 1:05 p.m. and fire its thrusters to move a safe distance away from the station after receiving a command from ground controllers at SpaceX in Hawthorne, California.
The spacecraft arrived at the station March 23 and delivered more than 6,000 pounds of research investigations, crew supplies, and station hardware after it launched March 21 on a SpaceX Falcon 9 rocket from Launch Complex 39A at NASA Kennedy.
After re-entering Earth’s atmosphere, the spacecraft will splash down off the coast of Florida. NASA will not broadcast the splashdown, but updates will be posted on the agency’s space station blog.
Dragon will carry back to Earth more than 4,100 pounds of supplies and scientific experiments designed to take advantage of the space station’s microgravity environment. Splashing down off the coast of Florida enables quick transportation of the experiments to NASA’s Space Systems Processing Facility at Kennedy Space Center in Florida, allowing researchers to collect data with minimal sample exposure to Earth’s gravity.
Scientific hardware and samples returning to Earth include Flawless Space Fibers-1, which produced more than seven miles of optical fiber aboard the space station. The investigation tests new hardware and processes for producing high-quality optical fibers in space and drew more than half a mile of fiber in one day, surpassing the previous record of 82 feet for the longest fiber manufactured in space.
Other studies include GEARS (Genomic Enumeration of Antibiotic Resistance in Space), which surveys the space station for antibiotic-resistant organisms. Genetic analysis could show how these bacteria adapt to space, providing knowledge that informs measures designed to protect astronauts on future long-duration missions.
Also returning on Dragon is MISSE-18 (Materials International Space Station Experiment-18-NASA), which analyzes how exposure to space affects the performance and durability of specific materials and components. MISSE-18 includes coatings, quantum dots, a lunar regolith simulant composite, and other materials. The samples returning home were exposed to the harsh environment of space for six months.
Additionally, samples from Immune Cell Activation will return to Earth for analysis. The ESA (European Space Agency) sponsored experiment seeks to understand whether microgravity influences the incorporation of magnetic nanoparticles into immune and melanoma cells. In this experiment, immune cells were modified with nano-vectors that are intended to carry therapeutic agents specifically to their target cells. Results could help develop novel therapeutics targeting central nervous system diseases and skin cancers such as melanoma.
These are just a few of the hundreds of investigations currently being conducted aboard the orbiting laboratory in the areas of biology and biotechnology, physical sciences, and Earth and space science. Advances in these areas will help keep astronauts healthy during long-duration space travel and demonstrate technologies for future human and robotic exploration beyond low Earth orbit to the Moon and Mars through NASA’s Artemis campaign.
Get breaking news, images and features from the space station on Instagram, Facebook, and X.
Learn more about the International Space Station at:
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Josh Finch / Claire O’Shea
Headquarters, Washington
202-358-1100
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Johnson Space Center, Houston
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Site-Wide Environmental Assessment for Marshall Space Flight Center, Alabama
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater) Pictured at sunset is Marshall Space Flight Center’s Propulsion R&D Lab, Building 4205.NASA/Charles BeasonThe National Aeronautics and Space Administration (NASA) has prepared a Draft Environmental Assessment (EA) that analyzes the environmental impacts of implementing continuing and future mission support activities at the Marshall Space Flight Center (MSFC) in Huntsville, Alabama.
The EA evaluated the potential environmental effects associated with air quality; climate change and greenhouse gases; land use; water resources; biological resources; geology and soils; noise; traffic and transportation; socioeconomics; children’s environmental health and safety; environmental justice and equity; hazardous materials and wastes, solid waste, and pollution prevention; public and occupational health and safety; utilities and infrastructure; cultural resources; and airspace. The EA found that the Proposed Action would not result in, or contribute to, significant impacts to any of these resources.
Public comments will be accepted through March 4, 2024 and can be submitted to msfc-environmental@mail.nasa.gov or the mailing address below. Copies of the Draft EA are available at the following library locations: Huntsville-Madison County Public Library (915 Monroe Street SW, Huntsville, AL) and the Madison Public Library (142 Plaza Boulevard, Madison, AL). The EA will also be posted on the NASA NEPA Public Reviews webpage (https://nasa.gov/news-release/site-wide-environmental-assessment-for-marshall-space-flight-center-alabama/).
To request additional information or submit written comments, please contact:
Hannah McCarty
Marshall Space Flight Center
Building 4249/Mail Code AS10
Huntsville, AL 35812
Downloads Draft Site-Wide Environmental Assessment for Marshall Space Flight CenterFeb 1, 2024
PDF (22.84 MB)
Comment MatrixFeb 5, 2024
VND.OPENXMLFORMATS-OFFICEDOCUMENT.SPREADSHEETML.SHEET (24.23 KB)
Final Site-Wide Environmental Assessment for Marshall Space Flight CenterApr 26, 2024
PDF (23.29 MB)
Share Details Last Updated Apr 26, 2024 EditorMSFC Environmental Engineering and Occupational Health OfficeContactHannah McCartyLocationMarshall Space Flight Center Related Terms Explore More 6 min read NASA’s Optical Comms Demo Transmits Data Over 140 Million Miles Article 2 days ago 29 min read The Marshall Star for April 24, 2024 Article 2 days ago 4 min read NASA’s Chandra Releases Doubleheader of Blockbuster Hits Article 3 days ago Keep Exploring Discover Related TopicsMissions
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Read More Share Details Last Updated Apr 26, 2024 EditorMSFC Environmental Engineering and Occupational Health OfficeContactHannah McCartyLocationMarshall Space Flight Center Related TermsBoeing Starliner 1st astronaut flight: Live updates
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NASA-Led Study Provides New Global Accounting of Earth’s Rivers
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater) The Colorado River supplies water to more than 40 million people as it snakes through seven U.S. states, including the part of southeastern Utah seen in this photo snapped by an astronaut aboard the International Space Station. The Colorado basin was identified in a NASA-led study as a region experiencing intense human water use.NASAThe novel approach to estimating river water storage and discharge also identifies regions marked by ‘fingerprints’ of intense water use.
A study led by NASA researchers provides new estimates of how much water courses through Earth’s rivers, the rates at which it’s flowing into the ocean, and how much both of those figures have fluctuated over time — crucial information for understanding the planet’s water cycle and managing its freshwater supplies. The results also highlight regions depleted by heavy water use, including the Colorado River basin in the United States, the Amazon basin in South America, and the Orange River basin in southern Africa.
For the study, which was recently published in Nature Geoscience, researchers at NASA’s Jet Propulsion Laboratory in Southern California used a novel methodology that combines stream-gauge measurements with computer models of about 3 million river segments around the world.
A NASA-led study combined stream-gauge measurements with computer models of 3 million river segments to create a global picture of how much water Earth’s rivers hold. It estimated that the Amazon basin contains about 38% of the world’s river water, the most of any hydrological region evaluated. NASAThe scientists estimate that the total volume of water in Earth’s rivers on average from 1980 to 2009 was 539 cubic miles (2,246 cubic kilometers). That’s equivalent to half of Lake Michigan’s water and about 0.006% of all fresh water, which itself is 2.5% of the global volume. Despite their small proportion of all the planet’s water, rivers have been vital to humans since the earliest civilizations.
Although researchers have made numerous estimates over the years of how much water flows from rivers into the ocean, estimates of the volume of water rivers collectively hold — known as storage — have been few and more uncertain, said JPL’s Cédric David, a co-author of the study.
He likened the situation to spending from a checking account without knowing the balance. “We don’t know how much water is in the account, and population growth and climate change are further complicating matters,” David said. “There are many things we can do to manage how we’re using it and make sure there is enough water for everyone, but the first question is: How much water is there? That’s fundamental to everything else.”
The NASA-led study estimated flow through 3 million river segments, identifying locations around the world marked by intense human water use, including parts of the Colorado, Amazon, Orange, and Murray-Darling river basins, shown as gray here. NASAEstimates in the paper could eventually be compared with data from the international Surface Water and Ocean Topography (SWOT) satellite to improve measurements of human impacts on Earth’s water cycle. Launched in December 2022, SWOT is mapping the elevation of water around the globe, and changes in river height offer a way to quantify storage and discharge.
‘Fingerprints’ of Water UseThe study identified the Amazon basin as the region with the most river storage, holding about 204 cubic miles (850 cubic kilometers) of water — roughly 38% of the global estimate. The same basin also discharges the most water to the ocean: 1,629 cubic miles (6,789 cubic kilometers) per year. That’s 18% of the global discharge to the ocean, which averaged 8,975 cubic miles (37,411 cubic kilometers) per year from 1980 to 2009.
Although it’s not possible for a river to have negative discharge — the study’s approach doesn’t allow for upstream flow — for the sake of accounting, it is possible for less water to come out of some river segments than went in. That’s what the researchers found for parts of the Colorado, Amazon, and Orange river basins, as well as the Murray-Darling basin in southeastern Australia. These negative flows mostly indicate intense human water use.
“These are locations where we’re seeing fingerprints of water management,” said lead author Elyssa Collins, who conducted the analysis as a JPL intern and doctoral student at North Carolina State University in Raleigh.
A New Way to Quantify RiversFor decades, most estimates of Earth’s total river water were refinements of a 1974 United Nations figure, and no study has illustrated how the amount has varied with time. Better estimates have been hard to come by, David said, due to a lack of observations of the world’s rivers, particularly those far from human populations.
Another issue has been that there are many more stream gauges monitoring the levels and flow of large rivers than there are of small ones. There’s also broad uncertainty in estimates of land runoff — the rainwater and snowmelt that flow into rivers.
The new study started from the premise that runoff flowing into and through a river system should roughly equal the amount that gauges measure downstream. Where the researchers found inconsistencies between simulated runoff from three land surface models and gauge measurements taken from approximately 1,000 locations, they used the gauge measurements to correct the simulated runoff numbers.
Then they modeled the runoff through rivers on a high-resolution global map developed using land-elevation data and imagery from space, including from NASA’s Shuttle Radar Topography Mission. This approach yielded discharge rates, which were used to estimate average and monthly storage for individual rivers and the planet’s rivers in total.
Using a consistent methodology enables comparisons in flow and human drawdown between different regions.
“That way we can see where in the world the most amount of river water is stored, or where the most amount of water is being emptied into oceans from rivers,” said Collins, now a postdoctoral researcher at the University of North Carolina at Chapel Hill.
News Media ContactsAndrew Wang / Jane J. Lee
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626-379-6874 / 818-354-0307
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Share Details Last Updated Apr 26, 2024 Related Terms Explore More 4 min read NASA’s ORCA, AirHARP Projects Paved Way for PACE to Reach Space Article 19 hours ago 5 min read NASA’s CloudSat Ends Mission Peering Into the Heart of Clouds Article 4 days ago 3 min read NASA Data Helps Beavers Build Back Streams Article 1 week ago Keep Exploring Discover Related TopicsMissions
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Hubble Spots a Magnificent Barred Galaxy
Laser on NASA's Psyche asteroid probe beams data from 140 million miles away
Hubble Spots a Magnificent Barred Galaxy
The magnificent central bar of NGC 2217 (also known as AM 0619-271) shines bright in the constellation of Canis Major (The Greater Dog), in this image taken by the NASA/ESA Hubble Space Telescope. Roughly 65 million light-years from Earth, this barred spiral galaxy is a similar size to our Milky Way at 100,000 light-years across. Many stars are concentrated in its central region forming the luminous bar, surrounded by a set of tightly wound spiral arms.
The central bar in these types of galaxies plays an important role in their evolution, helping to funnel gas from the disk into the middle of the galaxy. The transported gas and dust are then either formed into new stars or fed to the supermassive black hole at the galaxy’s center. Weighing from a few hundred to over a billion times the mass of our Sun, supermassive black holes are present in almost all large galaxies.
This image was colorized with data from the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS).
Text credit: European Space Agency (ESA)
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Identification of Noise Sources During Launch Using Phased Array Microphone Systems
Identification of Noise Sources During Launch Using Phased Array Microphone Systems
Every part of a launch vehicle, launch pad, and ground operation equipment is subjected to the high acoustic load generated during lift-off [1]. Therefore, many extreme measures are taken to try to suppress this acoustic environment by damping with a water deluge system and diverting engine plumes away from the vehicle via flame trenches. Even single decibel reductions of the acoustic levels can translate into a sizable reduction of acoustic loadings, certification needs, operational costs, and even vehicle weight. Therefore, lowering the acoustic level via various mitigation schemes is an important aspect of a launch pad design.
In 2011 and 2012, the NESC sponsored research into the effectiveness of a microphone phased array (MPA) to identify noise sources and tested the array during an Antares launch from the Wallops Flight Facility [2]. This simple prototype array was able to identify impingement-related noise sources during the launch.
Today, building on this previous work, a new open-space truss MPA architecture is in development and test for use during the Artemis II launch. This truss structure consists of an aluminum tubular frame holding 70 microphones mounted in optimized positions over a dome-shaped surface (Figure 1). The center canister structure holds visible and infrared cameras as well as the amplifier electronics that transfer and relay microphone signals out to data cables that send information to the ground-mounted data acquisition system. The collected data are postprocessed using a functional-orthogonal beamforming routine that minimizes the effects of side lobes and reflections on the acoustic signal [3]. This produces a much cleaner image of primary noise impingement sources emanating from the vehicle and launch pad structures.
Figure 1. Overall view of the MPA, cable bundle, and data acquisition cabinet.The NESC activity is performing verification and validation tests to determine the MPA’s environmental survivability and validate the beamforming capability. This is being done using a phased testing approach. Phase 1 testing performed at ARC elevated the MPA (Figure 2) and used horns and speakers of known intensity to ensure its ability to identify and separate noise sources (Figure 3).
Figure 2. Setup for the outdoor test using a train horn and a long-range acoustic device (LRAD) speaker. The MPA was raised to test heights by a Telehandler. Figure 3. Comparison between different beamform schemes at a fixed f=1338 Hz with array center 100 ft. horizontal and 10 ft. above LRAD speaker.In phase 2, the system was subjected to an actual engine noise environment during a static fire test at SSC. The MPA viewed the A-1 engine test stand during an RS-25 engine test from 460 feet, a similar distance from KSC Pad 39B to the lightning tower, where the MPA will be mounted for Artemis II (Figure 4). Results successfully identified and pinpointed the transient engine acoustic sources during the test (Figure 5).
Figure 4. Scaffold system used to mount MPA and location of the array with respect to the SSC A-1 test stand. Right Image Credit: Google Maps Noise sources identified at the indicated third-octave center frequencies using functional-orthogonal beamform.The final test occurred during the NG-19 Antares launch from the Wallops Flight Facility in July 2023. The MPA tracked the plume and acoustic environment during the launch, showing transition from initial engine thrust to the overpressure environment flowing from the flame trench as the vehicle lifted off (Figure 6). The array was able to collect meaningful data while mounted outside, under acoustic conditions similar to those expected during the Artemis II launch and also subjected to heat, humidity, salt air, and extreme weather.
Figure 6. Time evolution of noise source generation during the NG-19 launch. The acoustic intensity of the redirected flow from the flame trench opening evolves to become a much stronger noise source, while acoustics from the plume are effectively mitigated by the sound suppression on the launch pad surface.Next, the MPA will be deployed at KSC for the Artemis II launch to measure the acoustic impingement and identify critical noise sources during that event. The data collected will help further refine and optimize the sound suppression systems for Artemis III and future launches.
References:
- Eldred, K. M. & Jones, G. W., Jr., “Acoustic load generated by the propulsion system,” NASA SP-8072, 1971.
- Panda, J., Mosher, R. N. & Porter, B. J., “Noise Source Identification During Rocket Engine Test Firings and a Rocket Launch,” Journal of Spacecraft and Rockets, Vol. 51, No. 4, July-Aug 2014. DOI: 10.2514/1.A32863
- Dougherty, R.P., “Functional Beamforming for Aeroacoustic Source Distributions,” 20th AIAA/CEAS Aeroacoustics Conference, 10.2514/6.2014-3066, 2014.
For more information, contact:
Dr. Jayanta Panda jayanta.panda-1@nasa.gov
Kenneth R. Hamm, Jr. kenneth.r.hamm@nasa.gov
Joel W. Sills joel.w.sills@nasa.gov
