Caltech: NASA’s New Space Mission Explores Mysteries of Exoplanets and Dark Energy

NASA has recently selected a new satellite mission, called Landolt, that will put an artificial star in orbit around Earth. This artificial star, a source of light whose brightness is precisely known, will allow scientists to more accurately measure the brightness of actual stars, including those nearby to those exploding as supernova in far-off galaxies. By enabling better characterization of stars, the $19.5 million mission will lead to a better understanding of planets that orbit some of these stars. Additionally, it will provide new clues to the mystery of dark energy, a force or substance thought to be pushing our universe apart at ever-increasing speeds.

“Even with today’s modern instruments, measurements of the true brightness of stars have only been known to a few percent,” says David Ciardi, the deputy director for the NASA Exoplanet Science Institute (NExScI) at IPAC, an astronomy center based at Caltech. “Landolt will enable an improvement in those measurements by more than a factor of 10. Understanding the true brightness of stars allows us to understand the stars better, and, perhaps more importantly, understand the planets that orbit the stars better.”

The mission, planned for launch in 2029, is led by a former IPAC scientist and Caltech alum Peter Plavchan (BS ’01), who is now an associate professor of physics and astronomy at George Mason University in Virginia.

IPAC will be responsible for archiving the mission’s data and will contribute to the ground support through Caltech’s Palomar Observatory. Additional partners include the National Institute of Standards and Technology, a world leader in measuring photon emissions, in addition to several other universities. Other Caltech team members include Jessie Christiansen, the NExScI chief scientist and the project scientist for the NASA Exoplanet Archive at NExScI, who helped propose the mission.

Named for late astronomer Arlo Landolt, who put together widely used catalogs of stellar brightness in 1973, 1982, and 1992, and who passed away in 2022, this mission will launch a light source into the sky with a known emission rate of photons. The team will observe the light source, or artificial star, next to real stars to make new stellar brightness catalogs. The artificial star will orbit 22,236 miles above Earth, far enough away to look like a star to telescopes on the ground. This orbit also allows the satellite to move at the same speed of the Earth’s rotation, keeping it in place over the United States during its one-year primary mission.