GMU announces space mission to unlock secrets of dark energy

George Mason University is poised to take a big step forward in astrophysics with NASA’s $19.5 million Landolt space mission. This mission, which will place an artificial “star” in orbit around the Earth, is a game-changer. It will allow scientists to calibrate telescopes and measure the brightness of stars with unprecedented precision, from our cosmic neighbors to explosive supernovas in distant galaxies. By establishing an absolute flux calibration, the mission will tackle key challenges in astrophysics, including the mysteries of dark energy and the expansion of the universe.

“This mission marks another first for George Mason University, an important milestone that demonstrates that our impact as a major public research university truly knows no bounds,” said George Mason University President Gregory Washington. “It is an honor for George Mason to lead this unique team that seeks to push the boundaries of knowledge through College of Science Associate Professor Peter Plavchan’s collaboration with NASA, one of the most prestigious research partners by George Mason.”

Scientists know that the universe is expanding, as measured by the brightness of many stars and the number of photons per second they emit. According to Plavchan, associate professor of physics and astronomy at George Mason and principal investigator of the Landolt mission, more precise measurements are needed for future advances.

Named for the late astronomer Arlo Landolt, who collected widely used catalogs of stellar brightness throughout the 1970s through the 1990s, this mission will launch a light into the sky in 2029 with an emission rate of known photons, and the team will observe it next to real stars to create new catalogs of stellar brightness. The satellite (artificial star) will have eight lasers shining on optical telescopes on the ground to calibrate them for observations. This effort won’t make the artificial stars bright enough to be seen with the naked eye, but they can be seen with a personal telescope at home.

NASA’s Landolt space mission isn’t just about launching an artificial star. It’s about revolutionizing our understanding of the universe. As NASA Goddard mission and instrument scientist and Landolt deputy principal investigator Eliad Peretz explains, this mission is a game-changer. This involves measuring the fundamental properties which are the constituent elements of astronomical observations. It has the potential to reshape our understanding of stars, surface temperatures and the habitability of exoplanets, opening new frontiers in astrophysics.

The artificial star will orbit Earth at an altitude of 22,236 miles, far enough to look like a star to Earth’s telescopes. This orbit also allows it to move at the same speed as Earth’s rotation, keeping it in place above the United States during its first year in space. “This is what is considered an infrastructure mission for NASA, supporting science in a way that we knew we needed to do, but with a transformative change in how we do it,” Plavchan explained.

The payload, which is the size of a proverbial breadbox, will be built in partnership with the National Institute of Standards and Technology (NIST), a world leader in measuring photon emissions. “This calibration under a known wavelength and laser power will remove the effects of atmospheric filtration of light and allow scientists to significantly improve measurements,” explained Peter Pachowicz, associate professor in the Department of Electrical and Computer Engineering at Mason, who leads this component of the mission.

George Mason faculty and students from Mason’s College of Science and College of Engineering and Computing will work with NASA, NIST and nine other organizations on a first-of-its-kind project for a Washington, D.C.-area university. Pachowicz added, “This is an incredibly exciting opportunity for George Mason and our students. Our team will design, build and integrate the payload which, because it goes very high into geostationary orbit, will face 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 Hawaii; the University of Minnesota, Duluth; and the University of Victoria.

With more precise measurements, experts will use the project’s improved data to improve understanding of stellar evolution, habitable zones or exoplanets near Earth, and refine dark energy parameters, thereby throwing out the foundations for the next big steps forward in scientific discovery. “When we look at a star with a telescope, no one today can tell you the rate of photons or the brightness coming from it with the level of precision we want,” said Plavchan, who is also director of the Mason Observatories in Fairfax. “We will now know exactly how many photons per second are coming out of this source with an accuracy of 0.25 percent.”

“Flux calibration is essential for astronomical research,” explained NIST’s Susana Deustua, a physicist in NIST’s Remote Sensing Group. “We’re constantly asking, ‘How big?’ What brightness? Until what point?’ » then think: “What is the universe made of? Are we alone?’ Accurate answers require precise measurements and excellent instrument characterization.