Engineers and scientists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, completed tests this month on a second early version of a key element of the upcoming LISA (Laser Interferometer Space Antenna) mission.
The LISA mission, a collaboration between ESA (the European Space Agency) and NASA, will use infrared lasers to detect gravitational waves, or ripples in the fabric of space-time. The tests involved the frequency reference system, delivered by BAE Systems, that will help control the lasers connecting LISA’s three spacecraft. The lasers must be finely tuned to make precise measurements — to within a trillionth of a meter, called a picometer.
The team tested the first version of the system in May 2025.
“The extensive round of checkouts on the frequency reference system last year were very successful,” said Ira Thorpe, the project scientist for LISA at NASA Goddard. “This second unit is identical, so our assessments this time around were less intense and preface a future cross-check of the two, which is the gold-standard for checking the stability of the system overall.”
In addition to the laser system, NASA is contributing the telescopes, devices to manage the buildup of onboard electrical charge, and the framework scientists will need to process the data the mission will generate.
NASA’s contributions are part of the agency’s efforts to innovate on ambitious science missions that will help us better understand how the universe works. LISA will also offer a major advancement in multimessenger astronomy, which is how scientists explore cosmic signals other than light.
The three LISA spacecraft will fly in a vast triangular formation that follows Earth as it orbits the Sun. Each arm of the triangle will stretch 1.6 million miles (2.5 million kilometers).
Each spacecraft will contain two free-floating cubes inside called proof masses. Arriving gravitational waves from throughout the universe will minutely change the lengths of the triangle’s arms. The lasers connecting the cubes will measure changes in their separation to within a distance smaller than a helium atom.
The enormous scale of the triangle will enable LISA to detect gravitational waves that cannot be found with ground-based facilities, such as those generated when massive black holes in the centers of galaxies merge. Scientists can use the data to learn about a source’s distance and physical properties.
The LISA mission is slated to launch in the mid-2030s.
By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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NASA’s Goddard Space Flight Center, Greenbelt, Md.
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