A telescope made entirely from a glass-ceramic material is moving toward its final preflight test version for LISA. NASA described the next development step on October 8, 2026. L3Harris Technologies will design, assemble and integrate the new Engineering Test Unit.
LISA is a planned space observatory for gravitational waves, tiny distortions of space-time caused by accelerating massive objects. It will use three spacecraft to measure changes in their separation. The European Space Agency leads the mission, with NASA contributing telescopes and other hardware.
Each side of the spacecraft triangle will span 2.5 million kilometers. Two telescopes on each spacecraft will send and receive infrared laser light. The measurements are intended to reveal distance changes smaller than the width of a helium atom, according to NASA.
Temperature stability is crucial for an instrument measuring such small changes. The telescopes use Zerodur, an amber-colored glass-ceramic whose shape changes very little across a wide temperature range. Gold coatings on the mirrors help reflect the infrared beams.
L3Harris delivered an earlier prototype in 2024. NASA says testing that unit has informed the next design. A metal structural model was also delivered in June 2026; it served a different engineering purpose from the optical glass telescope.
The new unit is not flight hardware and LISA is not observing yet. The mission is scheduled for the mid-2030s. Its long separations will open access to low-frequency gravitational waves that current ground-based facilities cannot detect.
The photograph shows the 2024 prototype, not the newly commissioned unit. The next step remains on the ground.
