SPACE/COSMOS
Europe's Hera spacecraft blasts off to investigate asteroid already rammed by NASA
The European Space Agency's Hera spacecraft set off on Monday on its two-year journey towards a small asteroid already rammed by NASA to test whether potentially planet-threatening asteroids can be bumped off course by a well-timed launch.
Issued on: 07/10/2024 -
A spacecraft blasted off Monday to investigate the scene of a cosmic crash.
The European Space Agency's Hera spacecraft rocketed away on a two-year journey to the small, harmless asteroid rammed by NASA two years ago in a dress rehearsal for the day a killer space rock threatens Earth. Launched by SpaceX from Cape Canaveral, it’s the second part of a planetary defense test that could one day help save the planet.
The 2022 crash by NASA's Dart spacecraft shortened Dimorphos' orbit around its bigger companion, demonstrating that if a dangerous rock was headed our way, there’s a chance it could be knocked off course with enough advance notice.
Scientists are eager to examine the impact’s aftermath up close to know exactly how effective Dart was and what changes might be needed to safeguard Earth in the future.
"The more detail we can glean the better as it may be important for planning a future deflection mission should one be needed,” University of Maryland astronomer Derek Richardson said before launch.
Researchers want to know whether Dart – short for Double Asteroid Redirection Test – left a crater or perhaps reshaped the 500-foot (150-meter) asteroid more dramatically. It looked something like a flying saucer before Dart’s blow and may now resemble a kidney bean, said Richardson, who took part in the Dart mission and is helping with Hera.
Dart’s wallop sent rubble and even boulders flying off Dimorphos, providing an extra kick to the impact’s momentum. The debris trail extended thousands of miles (more than 10,000 kilometers) into space for months.
Some boulders and other debris could still be hanging around the asteroid, posing a potential threat to Hera, said flight director Ignacio Tanco.
“We don't really know very well the environment in which we are going to operate,” said Tanco. "But that's the whole point of the mission is to go there and find out.”
European officials describe the $400 million (363 million euro) mission as a “crash scene investigation.”
Hera "is going back to the crime site and getting all the scientific and technical information,” said project manager Ian Carnelli.
Carrying a dozen science instruments, the small car-sized Hera will need to swing past Mars in 2025 for a gravity boost, before arriving at Dimorphos by the end of 2026. It's a moonlet of Didymos, Greek for twin, a fast-spinning asteroid that's five times bigger. At that time, the asteroids will be 120 million miles (195 million kilometers) from Earth.
Controlled by a flight team in Darmstadt, Germany, Hera will attempt to go into orbit around the rocky pair, with the flyby distances gradually dropping from 18 miles (30 kilometers) all the way down to a half-mile (1 kilometer). The spacecraft will survey the moonlet for at least six months to ascertain its mass, shape and composition, as well as its orbit around Didymos.
Before the impact, Dimorphos circled its larger companion from three-quarters of a mile (1,189 meters) out. Scientists believe the orbit is now tighter and oval-shaped, and that the moonlet may even be tumbling.
Two shoebox-sized Cubesats will pop off Hera for even closer drone-like inspections, with one of them using radar to peer beneath the moonlet’s boulder-strewn surface. Scientists suspect Dimorphos was formed from material shed from Didymos. The radar observations should help confirm whether Didymos is indeed the little moon’s parent.
The Cubesats will attempt to land on the moonlet once their survey is complete. If the moonlet is tumbling, that will complicate the endeavor. Hera may also end its mission with a precarious touchdown, but on the larger Didymos.
Neither asteroid poses any threat to Earth – before or after Dart showed up. That’s why NASA picked the pair for humanity’s first asteroid-deflecting demo.
Leftovers from the solar system’s formation 4.6 billion years ago, asteroids primarily orbit the sun between Mars and Jupiter in what’s known as the main asteroid belt, where millions of them reside. They become near-Earth objects when they’re knocked out of the belt and into our neck of the woods.
NASA’s near-Earth object count currently tops 36,000, almost all asteroids but also some comets. More than 2,400 of them are considered potentially hazardous to Earth.
(AP)
Miami (AFP) – Europe's Hera probe successfully launched Monday on a mission to inspect the damage done by a NASA spacecraft that smashed into an asteroid during the first test of Earth's planetary defences.
Issued on: 07/10/2024 -
Despite fears that an approaching hurricane could delay the launch, the probe blasted off on a SpaceX rocket into cloudy skies from Cape Canaveral in the US state of Florida just before 11:00 am local time (1500 GMT).
Hera's mission is to investigate the aftermath of NASA's Double Asteroid Redirection Test (DART), which deliberately crashed into the Dimorphos asteroid in 2022 roughly 11 million kilometres (6.8 million miles) from Earth.
The fridge-sized DART spacecraft successfully knocked the asteroid well off course, demonstrating that humanity may no longer be powerless against potentially planet-killing asteroids that could head our way.
The European Space Agency (ESA) said that Hera will conduct what it has dubbed a "crime scene investigation".
"Hera will gather the data we need to turn kinetic impact into a well-understood and repeatable technique on which all of us may rely one day," ESA chief Josef Aschbacher said on the agency's broadcast of the launch.
The tense liftoff on SpaceX's Falcon 9 rocket was met with applause from teams on the ground.
"We had a lot of tears -- and outside in the public event, people were jumping around and spilling their beers," ESA broadcast host Matthew Russell said.
Around an hour after liftoff, Hera then separated from the rocket in space, beginning its two-year journey towards Dimorphos.
There was more applause minutes later when the team on the ground received the first signal from the spacecraft, indicating a successful launch.
Hurricane, rocket anomaly
The launch had been put into doubt by the intensifying Hurricane Milton, with SpaceX warning on Sunday that there was only a 15 percent chance of a launch.
Milton is the latest hurricane to hit the Gulf of Mexico after Hurricane Helene, which has killed at least 230 people since striking Florida late last month.
Hurricane Milton has been classified as "an extremely dangerous category 4 hurricane" and is expected to slam into the state by mid-week.
NASA said it will delay the launch of its Europa Clipper mission, which had been scheduled from Cape Canaveral on Thursday, due to "anticipated hurricane conditions" as Milton moves east across Florida over the week.
Hera's launch had also faced a potential delay due to an anomaly involving a Falcon 9 rocket during the launch of SpaceX's Crew-9 astronaut mission late last month.
But on Sunday, the US Federal Aviation Administration gave the last-minute green light, saying the nature of the problem posed little risk for Hera.
Next year, Hera is planned to get a gravitational boost as it flies past Mars, arriving near Dimorphos in December 2026 to begin its six-month investigation.
Dimorphos, which is actually a moonlet orbiting its big brother Didymos, never posed a threat to Earth.
After DART's impact, Dimorphos shed material to the point where its orbit around Didymos was shortened by 33 minutes -- proof that it was successfully deflected.
Analysis of the DART mission has suggested that rather than being a single hard rock, Dimorphos was more a loose pile of rubble held together by gravity.
"The consequence of this is that, instead of making a crater" on Dimorphos, DART may have "completely deformed" the asteroid, said Hera's principal investigator Patrick Michel.
Nothing heading our way
The 363-million-euro ($400 million) mission will be equipped with two nanosatellites.
One will land on Dimorphos and probe inside the asteroid with radar, a first on such an asteroid. The other will study its composition from farther out.
An asteroid wider than a kilometre (0.6 miles) -- which could trigger a global catastrophe on a scale that wiped out the dinosaurs -- is estimated to strike Earth every 500,000 years or so.
An asteroid around 140 metres (460 feet) wide -- which is a little smaller than Dimorphos but could still take out a major city -- hits our home planet around every 20,000 years.
There are also no known 140-metre asteroids on a collision course with Earth -- but only 40 percent of those space rocks are believed to have been identified.
© 2024 AFP
Winds of change: James Webb Space Telescope reveals elusive details in young star systems
Astronomers have discovered new details of gas flows that sculpt planet-forming disks and shape them over time, offering a glimpse into how our own solar system likely came to be.
University of Arizona
image:
This artist’s impression of a planet-forming disk surrounding a young star shows a swirling "pancake" of hot gas and dust from which planets form. Using the James Webb Space Telescope, the team obtained detailed images showing the layered, conical structure of disk winds – streams of gas blowing out into space.
view moreCredit: National Astronomical Observatory of Japan (NAOJ)
Every second, more than 3,000 stars are born in the visible universe. Many are surrounded by what astronomers call a protoplanetary disk – a swirling "pancake" of hot gas and dust from which planets form. The exact processes that give rise to stars and planetary systems, however, are still poorly understood.
A team of astronomers led by University of Arizona researchers has used NASA's James Webb Space Telescope to obtain some of the most detailed insights into the forces that shape protoplanetary disks. The observations offer glimpses into what our solar system may have looked like 4.6 billion years ago.
Specifically, the team was able to trace so-called disk winds in unprecedented detail. These winds are streams of gas blowing from the planet-forming disk out into space. Powered largely by magnetic fields, these winds can travel tens of miles in just one second. The researchers' findings, published in Nature Astronomy, help astronomers better understand how young planetary systems form and evolve.
According to the paper's lead author, Ilaria Pascucci, a professor at the U of A's Lunar and Planetary Laboratory, one of the most important processes at work in a protoplanetary disk is the star eating matter from its surrounding disk, which is known as accretion.
"How a star accretes mass has a big influence on how the surrounding disk evolves over time, including the way planets form later on," Pascucci said. "The specific ways in which this happens have not been understood, but we think that winds driven by magnetic fields across most of the disk surface could play a very important role."
Young stars grow by pulling in gas from the disk that's swirling around them, but in order for that to happen, gas must first shed some of its inertia. Otherwise, the gas would consistently orbit the star and never fall onto it. Astrophysicists call this process "losing angular momentum," but how exactly that happens has proved elusive.
To better understand how angular momentum works in a protoplanetary disk, it helps to picture a figure skater on the ice: Tucking her arms alongside her body will make her spin faster, while stretching them out will slow down her rotation. Because her mass doesn't change, the angular momentum remains the same.
For accretion to occur, gas across the disk has to shed angular momentum, but astrophysicists have a hard time agreeing on how exactly this happens. In recent years, disk winds have emerged as important players funneling away some gas from the disk surface – and with it, angular momentum – which allows the leftover gas to move inward and ultimately fall onto the star.
Because there are other processes at work that shape protoplanetary disks, it is critical to be able to distinguish between the different phenomena, according to the paper's second author, Tracy Beck at NASA's Space Telescope Science Institute.
While material at the inner edge of the disk is pushed out by the star's magnetic field in what is known as X-wind, the outer parts of the disk are eroded by intense starlight, resulting in so-called thermal winds, which blow at much slower velocities.
"To distinguish between the magnetic field-driven wind, the thermal wind and X-wind, we really needed the high sensitivity and resolution of JWST (the James Webb Space Telescope)," Beck said.
Unlike the narrowly focused X-wind, the winds observed in the present study originate from a broader region that would include the inner, rocky planets of our solar system – roughly between Earth and Mars. These winds also extend farther above the disk than thermal winds, reaching distances hundreds of times the distance between Earth and the sun.
"Our observations strongly suggest that we have obtained the first images of the winds that can remove angular momentum and solve the longstanding problem of how stars and planetary systems form," Pascucci said.
For their study, the researchers selected four protoplanetary disk systems, all of which appear edge-on when viewed from Earth.
"Their orientation allowed the dust and gas in the disk to act as a mask, blocking some of the bright central star's light, which otherwise would have overwhelmed the winds," said Naman Bajaj, a graduate student at the Lunar and Planetary Laboratory who contributed to the study.
By tuning JWST's detectors to distinct molecules in certain states of transition, the team was able to trace various layers of the winds. The observations revealed an intricate, three-dimensional structure of a central jet, nested inside a cone-shaped envelope of winds originating at progressively larger disk distances, similar to the layered structure of an onion. An important new finding, according to the researchers, was the consistent detection of a pronounced central hole inside the cones, formed by molecular winds in each of the four disks.
Next, Pascucci's team hopes to expand these observations to more protoplanetary disks, to get a better sense of how common the observed disk wind structures are in the universe and how they evolve over time.
"We believe they could be common, but with four objects, it's a bit difficult to say," Pascucci said. "We want to get a larger sample with James Webb, and then also see if we can detect changes in these winds as stars assemble and planets form."
For a complete list of authors, please see the paper, "The nested morphology of disk winds from young stars revealed by JWST/NIRSpec observations," Nature Astronomy (DOI 10.1038/s41550-024-02385-7). Funding for this work was provided by NASA and the European Research Council.
Composite image showing nested morphology of disk winds emissions of protoplanetary disk HH30.
GB image of one of the sources described in the paper (HH30) shows for the first time the nested morphology of disk winds with multiple tracers: Fe[II] emission (in blue) traces the fastest and most collimated component (the jet). The Fe[II] emission is nested inside a lower velocity hydrogen emission (green), which is itself nested inside an even slower carbon monoxide (J=2-1) emission (red). Fe[II] and hydrogen emissions were obtained with JWST/NIRSpec, while the carbon monoxide emission was observed by ALMA (Atacama Large Millimeter Array) previously.
Credit
Ilaria Pascucci et al.
Journal
Nature Astronomy
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
The nested morphology of disk winds from young stars revealed by JWST/NIRSpec observations
Article Publication Date
4-Oct-2024
image:
Illustration of the global coronal magnetic field as the Sun rotates. The background is the solar corona observed in extreme-ultraviolet waveband, with global coronal magnetic field maps measured at different time overlapped on top of it.
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Credit: Image courtesy of Zihao Yang.
A new era of solar observation
International team produces global maps of coronal magnetic field
For the first time, scientists have taken near-daily measurements of the Sun’s global coronal magnetic field, a region of the Sun that has only been observed irregularly in the past. The resulting observations are providing valuable insights into the processes that drive the intense solar storms that impact fundamental technologies, and thus lives and livelihoods, here on Earth.
An analysis of the data, collected over eight months by an instrument called the Upgraded Coronal Multi-channel Polarimeter (UCoMP), is published today in Science.
The solar magnetic field is the primary driver of solar storms, which can pose threats to power grids, communication systems, and in-space technologies like GPS. However, our ability to understand how the magnetic field builds up energy and erupts has been limited by the challenge of observing it in the solar corona, the Sun’s upper atmosphere.
Measuring the magnetism of the region through standard polarimetric methods typically requires large, expensive equipment that to date has only been able to study small segments of the corona. However, the combined use of coronal seismology and UCoMP observations makes it possible for researchers to produce consistent and comprehensive views of the magnetic field of the global corona — the whole-Sun view one sees during a solar eclipse.
“Global mapping of the coronal magnetic field has been a big missing part in the study of the Sun,” said Zihao Yang, lead author who pursued this research as a PhD graduate at Peking University, China, and is now a postdoctoral fellow at the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR). “This research is helping us fill a crucial gap in our understanding of coronal magnetic fields, which are the source of the energy for storms that can impact Earth.”
The international team is made of researchers from Northumbria University, UK; NSF NCAR; Peking University, China; and University of Michigan. The research was funded by a grant from the National Natural Science Foundation of China and the National Key R&D Program of China and supported by the Newkirk graduate student fellowship awarded to Yang by NSF NCAR. The UCoMP instrument was developed with support from the U.S. National Science Foundation (NSF) and is operated by NSF NCAR at the Mauna Loa Solar Observatory.
Upgraded instrument
Although scientists have been able to routinely measure the magnetic field on the Sun’s surface, known as the photosphere, it has long been difficult to measure the much dimmer coronal magnetic field. This has limited a deeper understanding of the three-dimensional structure and evolution of the magnetic field of the corona, where solar storms brew.
To measure the three-dimensional coronal magnetic fields in depth, big telescopes like NSF’s Daniel K. Inouye Solar Telescope (DKIST) are needed. With a 4-meter-diameter aperture, DKIST is the world’s largest solar telescope, and recently demonstrated its groundbreaking ability for making detailed observations of the coronal magnetic field. However, DKIST is not able to map the Sun all at once. The smaller UCoMP instrument is actually better-suited to give scientists global pictures of the coronal magnetic field, albeit at lower resolution and in a two-dimensional projection. The observations from both sources are thus highly-complementary to a holistic view of the coronal magnetic field.
UCoMP is primarily a coronagraph, an instrument that uses a disc to block out light from the Sun, similar to an eclipse, making it easier to observe the corona. It also combines a Stokes polarimeter, which images other spectral information such as coronal line intensity and Doppler velocity. Even though UCoMP has a much smaller aperture (20 cm), it is able to take a wider view which makes it possible to study the entire Sun on most days.
The researchers applied a method called coronal seismology to track magnetohydrodynamic (MHD) transverse waves in the UCoMP data. The MHD waves gave them information that made it possible to create a two-dimensional map of the strength and direction of the coronal magnetic field.
In 2020, a previous study used UCoMP’s predecessor and the coronal seismology method to produce the first map of the global coronal magnetic field. This was a crucial step toward routine coronal magnetic field measurements. UCoMP has expanded capabilities that makes it possible to make more detailed, routine measurements. During the UCoMP study, the research team produced 114 magnetic field maps between February and October 2022, or one almost every other day.
“We are entering a new era of solar physics research where we can routinely measure the coronal magnetic field,” said Yang.
Completing the picture
The observations also produced the first measurements of the coronal magnetic field in the polar regions. The Sun’s poles have never been directly observed because the curve of the Sun near the poles keeps it just beyond our view from Earth. Though the researchers didn’t directly view the poles, for the first time they were able to take measurements of the magnetism emitting from them. This was due in part to the improved data quality provided by UCoMP and because the Sun was near solar maximum. The typically weak emissions from the polar region have been much stronger, making it easier to obtain coronal magnetic field results in the polar regions.
As a postdoctoral fellow at NSF NCAR, Yang will continue his research of the Sun’s magnetic field; he hopes to improve existing coronal models that are based on measurements of the photosphere. Since the current method used with UCoMP is limited to two dimensions, it still doesn’t capture the full three-dimensional magnetic field. Yang and his colleagues hope to combine their research with other techniques to get a deeper understanding of the full vector of the magnetic field in the corona.
The third dimension of the magnetic field, oriented along a viewer's line of sight, is of particular importance for understanding how the corona is energized leading up to a solar eruption. Ultimately, a combination of a large telescope and a global field of view is needed to measure all the three-dimensional twists and tangles behind phenomena like solar eruptions; this is the motivation behind the proposed Coronal Solar Magnetism Observatory (COSMO), a 1.5-meter-diameter solar refracting telescope undergoing its final design study.
“Since coronal magnetism is the force that sends mass from the Sun flying across the solar system, we have to observe it in 3D — and everywhere all at once, throughout the global corona,” said Sarah Gibson, COSMO Development Lead and an NSF NCAR scientist co-author on the paper. "Yang's work represents a huge step forward in our ability to understand how the Sun's global coronal magnetic field changes from day to day. This is critical to our ability to better predict and prepare for solar storms, which are an ever-increasing danger to our ever-more technologically dependent lives here on Earth."
About the article:
Title: Observing the evolution of the Sun’s global coronal magnetic field over eight months
Authors: Zihao Yang, Hui Tian, Steven Tomczyk, Xianyu Liu, Sarah Gibson, Richard J. Morton, and Cooper Downs
Journal: Science
This material is based upon work supported by the NSF National Center for Atmospheric Research, a major facility sponsored by the U.S. National Science Foundation and managed by the University Corporation for Atmospheric Research. Any opinions, findings and conclusions or recommendations expressed in this material do not necessarily reflect the views of NSF.
Journal
Science
Method of Research
Observational study
Article Title
Observing the evolution of the Sun’s global coronal magnetic field over eight months
Article Publication Date
4-Oct-2024
The University of Texas at San Antonio is advancing space exploration as the lead of a multimillion-dollar DOE project
University of Texas at San Antonio
image:
The University of Texas at San Antonio is advancing interplanetary space exploration as the lead of a multimillion-dollar project that will stimulate nuclear energy research. UTSA was selected by the U.S. Department of Energy's Office of Nuclear Energy.
view moreCredit: The University of Texas at San Antonio
UTSA was selected by the U.S. Department of Energy’s (DOE) Office of Nuclear Energy (NE) to lead a multimillion-dollar project that will stimulate nuclear energy research at UTSA, leverage novel experimental data to bolster computational efforts at the university, and provide professional training to prepare undergraduate and graduate students for careers in nuclear energy science. UTSA researchers will collaborate with a leading nuclear energy laboratory as well as across academic institutions.
The award is part of the DOE’s Nuclear Energy University Program’s Integrated Research Projects (IRPs). These projects aim to provide research and development solutions that are relevant to the DOE. Each IRP is a three-year, multimillion-dollar project executed by university-led consortiums that typically include multiple universities, industry, national laboratories, and international research entities. IRPs are highly competitive, with only three FY 2024 Integrated Research (IRP) Projects being awarded by the DOE NE this year. As the lead institution, UTSA is designated to receive over half of the award, which is around $1.5 million of the $3 million award.
“This research will contribute to the knowledge base and understanding of novel nuclear fuels proposed to power advanced systems that will bring us all one step closer to achieving our clean energy and climate goals, while also advancing space exploration beyond our planet,” said Elizabeth Sooby, principal investigator on the project and associate professor in the UTSA Department of Physics and Astronomy.
The project is entitled, “Experimental and Computational assessment of thermodynamic stability of fission products in advanced reactor fuels.” UTSA will collaborate with the University of Texas at El Paso (UT El Paso) and Idaho National Laboratory (INL), a leading DOE NE national laboratory, to investigate fission product (FP) behavior in advanced reactor fuels.
Fission products (FPs) are particles that remain after nuclear fission, the process that occurs when a nucleus is split into two smaller nuclei to generate energy. This project will utilize experimental and computational methods to investigate FPs and their influence on the thermal and mechanical properties of advanced reactor fuels, specifically uranium mononitride (UN).
UN is a chemical compound that refers to an oxidation state where nitrogen binds to the fissile fuel-uranium. UN is known for its high uranium density as well as high thermal conductivity which results in more efficient power production and heat transfer.
Uranium nitrides are seen by the nuclear materials community as exciting candidate fuels for advanced nuclear systems, including space nuclear propulsion and advanced civilian power systems.
“Nuclear reactor developers all over the U.S. are proposing designs for safer, more economical, proliferation resistance systems,” added Sooby. “Many of these new technologies necessitate the use of nuclear fuels which are not yet on the market. Further, with the push to go to Mars, there’s a great deal of attention being placed on space nuclear power systems to both power habitats and space craft.”
Sooby has spent 15 years of her scholarly career dedicated to the materials science investigations of emerging materials for energy technologies. Since arriving at UTSA in 2017, Sooby has built and leads the Extreme Environments Materials Laboratory, which is bridging data gaps and advancing the fundamental understanding of uranium-bearing compounds that can be used as fuel forms for nuclear reactors.
This laboratory includes equipment that can synthesize, characterize and test these compounds safely under reactor-relevant conditions that encompass both normal operation and accident scenarios.
Sooby’s collaborators include Xochitl Lopez-Lozano and Patrick Warren, associate professor and assistant professor of research, respectively, in the university’s physics and astronomy department; Eunja Kim and Mark Pederson, professors in the Department of Physics at UT El Paso; Tiankai Yao, a staff scientist at the Characterization & Advanced PIE division of Materials and Fuel Complex at Idaho National Laboratory; and Mira Khair, a postdoctoral fellow in the UTSA Department of Physics and Astronomy. Additionally, the team will recruit two UTSA graduate students and over 15 undergraduates to assist with the project.
“We will combine our world-class capabilities with experimental expertise and experience in synthesis and testing of uranium compounds to advance the world’s understanding of fission product mobility in non-oxide fuels,” said Sooby. “This discovery will propel us forward by granting greater access to cleaner and more efficient forms of nuclear energy that will help us achieve our current climate and space propulsion goals.”
