A scientific research consortium on Tuesday announced plans to build and launch a privately financed telescope the size of a small washing machine in hopes of finding an Earthlike planet in the Alpha Centauri system, one of our closest cosmic neighbors.

Jon Morse, the chief executive of the BoldlyGo Institute, one of two nonprofits leading the consortium, called it “the holy grail of exoplanet research.” If there is a “pale blue dot” — a world covered in oceans — at Alpha Centauri, the telescope would permit scientists to study it in detail, looking for signs of life in the light reflected off the atmosphere.

To be built by the end of the decade, the telescope is the type of mission that NASA rarely undertakes, experts noted: tightly focused and cheap, leading to momentous discoveries — or possibly nothing at all.

The two stars of the Alpha Centauri system are both similar to the sun, the closest such stars at 4.37 light-years away. The proposed telescope, with a mirror only about 20 inches across, would be able to make out Earth-size planets orbiting in the stars’ so-called habitable zone, where temperatures are warm enough for liquid water to flow at the surface and, hypothetically, for life to thrive.