SpaceTech Videos

Hardest Lagrange Point, Voyagers' Realistic Lifetime, Goals for Telescopes | Q&A 387

The latest episode of the “Question Show” tackled a range of space‑science topics, from the feasibility of using the Sun‑Earth L3 Lagrange point to the remaining operational life of the Voyager probes and the scientific goals of the upcoming generation of giant ground‑based telescopes. The host explained that although L3 is gravitationally unstable, a spacecraft there could form part of a colossal interferometer with L4 and L5, creating a 250‑million‑kilometre baseline for radio imaging of black‑hole event horizons. Voyager 1 and 2 are expected to lose sufficient power to run their transmitters within roughly ten years as their plutonium‑235 thermoelectric generators decay. The golden records attached to the Voyagers are engineered to survive about a billion years, making them humanity’s longest‑lasting artifacts in interstellar space. Detecting true intergalactic interlopers would rely on measuring velocities exceeding the Milky Way’s 250 km/s escape speed, a clear signature distinct from typical interstellar objects. “If we placed assets at L3, L4 and L5, we could keep a near‑perfect equilateral triangle within 10,000 km,” the presenter noted, highlighting the unprecedented resolution such a formation could achieve. He also quoted NASA’s estimate that the Voyagers have “about ten years left” before a complete shutdown. The discussion of the Extremely Large Telescope (ELT) emphasized its 39‑metre aperture, slated for first light in 2027, and its capability to directly image Earth‑sized planets around Sun‑like stars. These insights underscore strategic priorities: developing Lagrange‑point interferometry could revolutionize high‑resolution astronomy, while the imminent Voyager silence calls for new deep‑space probes with longer‑lasting power sources. The durability of the golden records raises questions about preserving civilization’s legacy, and the ELT’s exoplanet focus signals a shift toward characterizing potentially habitable worlds. Meanwhile, asteroid platinum extraction remains cost‑prohibitive, suggesting resources should stay focused on scientific rather than commercial exploitation for now.