Image of the sun from the ESA/NASA Solar Orbiter mission. The diagram shows the increase in density in the atmosphere and the subsequent loss of altitude of a satellite at 490 km - both caused by a coronal mass ejection on November 21, 2003. Image source: ESA & NASA/Solar Orbiter/EUI team - Data: TU Graz & Uni Graz
Image of the sun from the ESA/NASA Solar Orbiter mission. The diagram shows the increase in density in the atmosphere and the subsequent loss of altitude of a satellite at 490 km - both caused by a coronal mass ejection on November 21, 2003. Image source: ESA & NASA/Solar Orbiter/EUI team - Data: TU Graz & Uni Graz
Tyler O'Neal, Staff Editor ENGINEERING

Austrian scientists develop forecasting service for ESA's Space Safety Program

When it comes to space exploration, the safety of satellites is of utmost importance. But how can we predict and protect against the dangers of space weather? The effects of solar storms on Earth's atmosphere can crash satellites. Scientists from the Technical University Graz and the University of Graz in Austria have developed a new SODA forecasting service for the European Space Agency's Space Safety Program, claiming to provide a reliable and accurate way to anticipate the risks of space weather. But is this new service really up to the task?

After a successful test phase, the SODA ( Satellite Orbit DecAy ) service jointly developed by Graz University of Technology and Graz University of Technology has been part of the Space Safety Program of the European Space Agency ESA since mid-July. SODA provides accurate forecasts of the effects of solar storms on the orbits of low-Earth satellites. This makes TU Graz only the third Austrian institution to contribute to this ESA program. In addition to Seibersdorf Laboratories, the University of Graz had previously been part of the program with the Kanzelhöhe Observatory and the Institute of Physics.

The new forecast service is freely available via the ESA Space Weather Service and offers a warning time of around 15 hours. Since solar activity is expected to reach its maximum in the next two years, the commissioning of SODA is of additional relevance at the current time. The extent to which solar storms can affect the satellite orbit has already been demonstrated in the SWEETS project, which is funded by the Research Promotion Agency (FFG).shown, on whose results SODA is built. In this project, atmospheric density data was combined with real-time measurements of solar wind plasma and the interplanetary magnetic field to calculate the effects of solar events. During a large coronal mass ejection from the sun, it was found that satellites at an altitude of 490 kilometers lost up to 40 meters in altitude. At the beginning of February 2022, 38 Starlink satellites even crashed during commissioning at a flight altitude of 210 kilometers due to a solar storm.

Solar activity heading to a peak

The main reason for this is that the charged plasma particles that hit the earth's magnetic field after a solar flare heat up the upper layers of the earth's atmosphere so much that they expand and air resistance increases. This costs satellite speed and altitude. Due to the expected increase in solar activity over the next two years, ESA has already lifted some of its satellites several kilometers to safely get through this period. With its predictions, SODA is intended to create additional security. The Graz University of Technology contributed its expertise in the processing of satellite data at the Institute for Geodesy for the forecast service, while the University of Graz contributed its experience in the field of solar and heliosphere physics and interplanetary magnetic field observation.

The team around Sandro Krauss at the Institute for Geodesy at TU Graz dealt with the determination of atmospheric densities over a period of 20 years. To do this, they drew on data from several near-Earth satellite missions, including the CHAMP, GRACE, GRACE Follow-on, and Swarm missions. At the University of Graz, the research group led by Manuela Temmer from the Institute of Physics analyzed around 300 cataloged solar flares from the years 2002 to 2017 based on measurements of the interplanetary magnetic field by probes at the so-called Lagrange point L1, which is about 1.5 million kilometers in the direction of the sun's flight is distant from the earth. The Graz University of Technology used the information from the University of Graz to link changes in the density of the atmosphere to solar flares. The SODA prediction model was created from the overall analysis of the data collected in this way.

Space research is very important in Austria

"I am very pleased that with SODA we are now, with TU Graz, the third institution to contribute to ESA's Space Safety Program alongside the University of Graz and Seibersdorf Laboratories," says Sandro Krauss from the Institute for Geodesy at TU Graz. “Of the five Expert Service Centers in the ESA Space Weather Service Network, Austria is represented in four; only Great Britain is involved in all five centers. This shows that Austrian space research is of great importance. The cooperation with the University of Graz on this project is also proof of how valuable interdisciplinary research work is. We are already working together to further improve SODA.”

Manuela Temmer from the Institute of Physics at the University of Graz explains: "For the University of Graz and the Graz University of Technology, it is a nice recognition of our work that we can supply the ESA with this service. I am also pleased that the cooperation is continuing. As part of the CASPER project funded by the FFG, we will improve SODA together. It should serve to better understand more complex solar storms, for example when two storms overlap on the way to Earth. Furthermore, we would also like to calculate the atmospheric density at an altitude of 450 and 400 kilometers - so far we have been able to do this up to 490 kilometers. Since the field of solar storm forecasting has not yet been very well researched, many interesting findings are still waiting for us.”

The new forecast service developed by TU Graz and Uni Graz for ESA's Space Safety Program is a promising development for the future of space exploration. However, it is important to remain skeptical and to continue to monitor the effectiveness of the service in order to ensure that it is providing the most accurate and reliable predictions for space weather and satellite safety. Only then will we be able to ensure that our space exploration efforts are safe and successful.

Oliktok Point research facility in Alaska, where the DAS experiment was headquartered. | Sandia National Laboratories
Oliktok Point research facility in Alaska, where the DAS experiment was headquartered. | Sandia National Laboratories

What are the advantages of using telecommunications cable to track sea ice extent in the Arctic?

Tyler O'Neal, Staff Editor ENGINEERING

A telecommunications fiber optic cable deployed offshore of Oliktok Point, Alaska recorded ambient seismic noise that can be used to finely track the formation and retreat of sea ice in the area, researchers report in The Seismic Record. Map of Oliktok Point and layout of the submarine fiber optic cable (gray line). Distributed Acoustic Sensing (DAS) recorded data for the first 37.4 km of the cable. Black diamonds and gray circles represent intervals of 5 km and 1 km, respectively, along the cable. Inset shows the location of Oliktok (red square) with respect to Alaska (United States).

Andres Felipe Peña Castro of the University of New Mexico and colleagues used distributed acoustic sensing, or DAS, to identify seismic signals related to the motion of waves on open water and the sea ice that suppresses that wave action. The technique offers a way to track sea ice with increasing spatial and temporal resolution—on the scale of hours and kilometers–compared to satellite images that are updated daily and may cover tens to hundreds of kilometers.

Swiftly monitoring sea ice changes is important to commercial shipping as well as Native communities and could become another useful tool in tracking Arctic climate change, the research team noted.

In the TSR study, the scientists were able to observe abrupt changes in sea ice extent up to 10 kilometers that occurred in less than a day.

“It was definitely surprising that the sea ice can change so much in a few hours,” said Peña Castro. “A few colleagues have mentioned that these rapid changes may be common but the temporal resolution of satellites makes it rare to observe such rapid changes in sea ice.”

DAS uses the tiny internal flaws in a long optical fiber as thousands of seismic sensors. An instrument called an interrogator at one end of the fiber sends laser pulses down the cable that are reflected off the fiber flaws and bounced back to the instrument. Researchers can examine changes in the timing of the reflected pulses to learn more about the resulting seismic waves.

Peña Castro and colleagues used a 37.4-kilometer-long section of seafloor fiber optic cable, part of a network owned by Quintillion Global and not actively carrying telecom data, in their DAS experiment. The DAS data were recorded between 9-15 July 2021 and 10-16 November 2021, times that were specifically targeted to capture periods of transitional sea ice coverage.

The original idea, said Peña Castro, was to classify different signals emerging from the interaction of ocean, earth, and atmosphere, such as potential local sea state and storm surges, shoaling, and sea ice fracturing. “We wanted to objectively identify the major types of signals in the data without assuming how many signals or which signals would be dominant,” he said. “We did not expect to observe changes in sea ice cover with such fine spatiotemporal detail.”

The researchers turned to machine learning algorithms to sort through the massive fiber optic data set. “In general, DAS generates large amounts of data that are impossible to process manually and that’s why we opted to use a machine learning approach that can identify possible patterns in the data,” Peña Castro explained. “Once a signal or pattern has been identified then we can consider how to track that signal most efficiently.”

The researchers were able to observe the formation of sea ice along the length of the cable, but not how far the ice spread perpendicular to the cable. They did not measure sea ice thickness in the TSR study, but Peña Castro said “In theory, it is possible to determine ice thickness using DAS. One difficulty is that ground truth measurements of ice thickness are necessary to validate proposed methods.”

The combination of machine learning and DAS techniques is already being used in the oil and gas industry, said Peña Castro. “In general, clustering techniques such as those used in this study may help identify lots of different types of change in environmental or anthropogenic signals that create ground vibrations.”

The results of this study demonstrate that telecommunications cable can be used to track sea ice extent in the Arctic with accuracy and precision. This technology can be used to monitor sea ice extent in real time, providing valuable information to those studying climate change and its effects on the Arctic region. Additionally, this technology can be used to help inform decisions related to Arctic shipping routes and other activities in the region.

Webb’s NIRCam (Near-Infrared Camera) instrument reveals the star, nicknamed Earendel, to be a massive B-type star more than twice as hot as our Sun, and about a million times more luminous. Credits: Image: NASA, ESA, CSA, D. Coe (STScI/AURA for ESA; Johns Hopkins University), B. Welch (NASA’s Goddard Space Flight Center; University of Maryland, College Park). Image processing: Z. Levay.
Webb’s NIRCam (Near-Infrared Camera) instrument reveals the star, nicknamed Earendel, to be a massive B-type star more than twice as hot as our Sun, and about a million times more luminous. Credits: Image: NASA, ESA, CSA, D. Coe (STScI/AURA for ESA; Johns Hopkins University), B. Welch (NASA’s Goddard Space Flight Center; University of Maryland, College Park). Image processing: Z. Levay.

Webb discovers colors of Earendel, the most distant star ever detected

Tyler O'Neal, Staff Editor ENGINEERING

The night sky has been a source of wonder and mystery since the dawn of time, and now astronomers have made a remarkable discovery that takes us further into the unknown. A team of astronomers has detected the colors of Earendel, the most distant star ever seen. This discovery is a testament to the power of human curiosity and exploration. 

NASA’s James Webb Space Telescope has followed up on observations by the Hubble Space Telescope of the farthest star ever detected in the very distant universe, within the first billion years after the big bang. Webb’s NIRCam (Near-Infrared Camera) instrument reveals the star to be a massive B-type star more than twice as hot as our Sun, and about a million times more luminous. This image from NASA’s James Webb Space Telescope of a massive galaxy cluster called WHL0137-08 contains the most strongly magnified galaxy known in the universe’s first billion years: the Sunrise Arc, and within that galaxy, the most distant star ever detected. In this image, the Sunrise Arc appears as a red streak just below the diffraction spike at the 5 o’clock position. Credits: Image: NASA, ESA, CSA, D. Coe (STScI/AURA for ESA; Johns Hopkins University), B. Welch (NASA’s Goddard Space Flight Center; University of Maryland, College Park). Image processing: Z. Levay.

The star, which the research team has dubbed Earendel, is located in the Sunrise Arc galaxy and is detectable only due to the combined power of human technology and nature via an effect called gravitational lensing. Both Hubble and Webb were able to detect Earendel due to its lucky alignment behind a wrinkle in space-time created by the massive galaxy cluster WHL0137-08. The galaxy cluster, located between us and Earendel, is so massive that it warps the fabric of space itself, which produces a magnifying effect, allowing astronomers to look through the cluster like a magnifying glass. 

While other features in the galaxy appear multiple times due to gravitational lensing, Earendel only appears as a single point of light even in Webb’s high-resolution infrared imaging. Based on this, astronomers determine the object is magnified by a factor of at least 4,000, and thus is extremely small – the most distant star ever detected, observed 1 billion years after the big bang. The previous record-holder for the most distant star was detected by Hubble and observed around 4 billion years after the big bang. Another research team using Webb recently identified a gravitationally lensed star they nicknamed Quyllur, a red giant star observed 3 billion years after the big bang.

Stars as massive as Earendel often have companions. Astronomers did not expect Webb to reveal any companions of Earendel since they would be so close together and indistinguishable from the sky. However, based solely on the colors of Earendel, astronomers think they see hints of a cooler, redder companion star. This light has been stretched by the universe's expansion to wavelengths longer than Hubble’s instruments can detect, and so was only detectable with Webb.

Webb’s NIRCam also shows other notable details in the Sunrise Arc, which is the most highly magnified galaxy yet detected in the universe’s first billion years. Features include both young star-forming regions and older established star clusters as small as 10 light-years across. On either side of the wrinkle of maximum magnification, which runs right through Earendel, these features are mirrored by the distortion of the gravitational lens. The region forming stars appears elongated and is estimated to be less than 5 million years old. Smaller dots on either side of Earendel are two images of one older, more established star cluster, estimated to be at least 10 million years old. Astronomers determined this star cluster is gravitationally bound and likely to persist until the present day. This shows us how the globular clusters in our own Milky Way might have looked when they formed 13 billion years ago.

Astronomers are currently analyzing data from Webb’s NIRSpec (Near-Infrared Spectrograph) instrument observations of the Sunrise Arc galaxy and Earendel, which will provide precise composition and distance measurements for the galaxy.

Since Hubble discovered Earendel, Webb has detected other very distant stars using this technique, though none quite as far as Earendel. The discoveries have opened a new realm of the universe to stellar physics, and new subject matter to scientists studying the early universe, where once galaxies were the most miniature detectable cosmic objects. The research team has cautious hope that this could be a step toward the eventual detection of one of the very first generation of stars, composed only of the raw ingredients of the universe created in the big bang – hydrogen and helium. 

Webb's discovery of the colors of Earendel, the most distant star ever detected, is a testament to the power of human curiosity and exploration. This discovery has pushed the boundaries of our knowledge and understanding of the universe and has inspired us to reach ever further into the unknown.