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LISA’s new telescope moves toward its final preflight test

NASA has commissioned a new engineering telescope for LISA, the planned space observatory for low-frequency gravitational waves. L3Harris will build the glass-ceramic unit using lessons from an earlier prototype. The telescope prepares the design for eventual flight hardware, while the European-led mission aims to measure tiny distance changes between three widely separated spacecraft. Launch is planned for the mid-2030s; this is not yet flight hardware.

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A large optical telescope component mounted on a test support in a bright laboratory.

A glass telescope prepares the flight design

NASA, the US space agency, has taken its next engineering step for LISA, the Laser Interferometer Space Antenna. L3Harris Technologies will design, assemble and integrate a new test telescope before production of the mission’s flight hardware. The Engineering Test Unit is planned as the final preflight unit and NASA’s first optical telescope delivery to the European Space Agency.[1], [2]

The entire telescope will use Zerodur, a glass-ceramic material that resists changes in shape as temperatures change. Precision distance measurements depend on that dimensional stability. NASA’s telescope team is incorporating lessons from the prototype L3Harris delivered in May 2024 and subsequently subjected to extensive tests.[1]

Three spacecraft will exchange infrared beams

LISA’s three spacecraft will follow Earth around the Sun, forming a triangle with sides 2.5 million kilometres long. Each will carry two telescopes directed at its neighbours, sending and receiving infrared laser beams simultaneously. Changes in the distances between them will provide the signal of passing gravitational waves. The European-led mission is scheduled to launch in the mid-2030s and targets low frequencies beyond the reach of current ground-based observatories.[1]

Free-floating cubes provide a gravity reference

Each spacecraft will contain a free-floating gold-platinum cube, its proof mass. Controlling the surrounding environment reduces forces other than gravity on the cube. LISA Pathfinder demonstrated this suppression in 2016. NASA also contributes lasers, charge-management devices and data-analysis expertise. The new optical unit follows a metal structural model delivered in June; it is still part of engineering preparation for flight.[1]

References

  1. News sourceNASALISA’s glass telescope moves to its final preflight engineering stage↩1↩2↩3↩4
  2. News sourceFinansTaksiNASA advances a new test telescope for LISA↩
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