George Mason University will be the home of the $19.5 million recently approved Landolt NASA Space Mission that will put an artificial “star” in orbit around the Earth. This artificial star will allow scientists to calibrate telescopes and more accurately measure the brightness of stars ranging from those nearby to the distant explosions of supernova in far-off galaxies. By establishing absolute flux calibration, the mission will begin to address several open challenges in astrophysics including the speed and acceleration of the universe expansion.
"This mission marks another first for George Mason University, a milestone that proves our impact as a major public research university truly knows no bounds,” George Mason University President Gregory Washington said. “It's an honor for George Mason to lead this unique team seeking to expand the boundaries of knowledge through College of Science associate professor Peter Plavchan’s collaboration with NASA, one of George Mason's most prestigious research partners.”
Scientists know the universe is expanding, which is measured by calculating the brightness of numerous stars and by the number of photons-per-second they emit. According to Plavchan, a George Mason associate professor of physics and astronomy and the Landolt Mission primary investigator, more accurate measurements are needed for the next breakthroughs.
Named for late astronomer Arlo Landolt, who put together widely used catalogs of stellar brightness throughout the 1970s through the 1990s, this mission will launch a light into the sky in 2029 with a known emission rate of photons, and the team will observe it next to real stars to make new stellar brightness catalogs. The satellite (artificial star) will have eight lasers shining at ground optical telescopes in order to calibrate them for observations. The effort will not make the artificial stars so brightly to see with the naked eye, but one can see it with a personal telescope at home.
“This mission is focused on measuring fundamental properties that are used daily in astronomical observations,” said Eliad Peretz, NASA Goddard mission and instrument scientist and Landolt’s deputy principal investigator. “It might impact and change the way we measure or understand the properties of stars, surface temperatures, and the habitability of exoplanets.”
The artificial star will orbit earth 22,236 miles up, far enough away to look like a star to telescopes back on Earth. This orbit also allows it to move at the same speed of the Earth’s rotation, keeping it in place over the United States during its first year in space. “This is what is considered an infrastructure mission for NASA, supporting the science in a way that we’ve known we needed to do, but with a transformative change in how we do it,” Plavchan explained.
The payload, which is the size of the proverbial bread box, will be built in partnership with the National Institute of Standards and Technology (NIST), a world leader in measuring photon emissions. “This calibration under known laser wavelength and power will remove effects of atmosphere filtration of light and allow scientists to significantly improve measurements,” said Piotr Pachowicz, associate professor in Mason’s Department of Electrical and Computer Engineering, who is leading this component of the mission.
George Mason faculty and students from Mason’s College of Science and College of Engineering and Computing will work together with the NASA and NIST and nine other organizations for a first-of-its-kind project for a university in the Washington, D.C., area.
“This is an incredibly exciting opportunity for George Mason and our students," said Pachowicz. "Our team will design, build, and integrate the payload, which—because it’s going very high into geostationary orbit—must handle incredible challenges.”
With mission control based at George Mason on its Fairfax Campus, the team also includes Blue Canyon Technologies; California Institute of Technology; Lawrence Berkeley National Laboratory; Mississippi State University; Montreal Planetarium and iREx/University of Montreal; the University of Florida; the University of Hawaiʻi; the University of Minnesota, Duluth; and the University of Victoria.
With more accurate measurements, experts will use the improved data from the project to enhance understanding of stellar evolution, habitable zones or exoplanets in proximity to Earth, and refine dark energy parameters, setting a foundation for the next great leaps in scientific discovery. “When we look at a star with a telescope, no one can tell you today the rate of photons or brightness coming from it with the desired level of accuracy,” Plavchan, who is also the director of Mason’s Observatories in Fairfax, said. “We will now know exactly how many photons-per-second come out of this source to .25 percent accuracy.”
"Flux calibration is essential for astronomical research.” explained NIST’s Susana Deustua, a physical scientist in the NIST Remote Sensing Group. “We constantly ask: ‘How big? How bright? How far?’ and then ponder: ‘What is the universe made of? Are we alone?’ Accurate answers require precise measurements and excellent instrument characterization,” Deustua said.
Learn more at landolt.gmu.edu
Did You Know
The Landolt Space Mission is named for the late astronomer Arlo Landolt, one of the most recognizable American astronomers. Renowned throughout the astronomical community for his discoveries, astronomers and physicists worldwide continue to use his series of papers, which established the “Landolt Photometric Standard Star Catalog,” and his standard stars are among the most heavily used photometric standards throughout the globe.