The James Webb Space Telescope is set to launch in 2018, successor to the game-changing Hubble Space Telescope. The Wide-Field Infrared Survey Telescope will come online in roughly a decade.

But a group of astronomers say it's time to think even further ahead -- about the next generation of deep space telescopes, specifically one that can find distant alien life.

"If we think about what we want in the sky after the James Webb Space Telescope, we need to start thinking about it now," Washington astronomy professor Julianne Dalcanton said in released statement. "These are decades-long projects. No mission happens accidentally."

Dalcanton, an astronomer at the University of Washington, recently co-chaired an Association of Universities for Research in Astronomy (AURA) committee on the future of space telescope technology. The group issued a "call to arms" to other astronomers, arguing the time is ripe to think big about the future of astronomical research. They also offered their idea for the next deep space telescope -- a project they call the High-Definition Space Telescope, or HDST.

The telescope's orbital path would lie one million miles from Earth, beyond the moon. It would peer deep into space, using a 40-foot-wide mirror to capture the faint light bouncing off faraway planets.

"The goal is not just to find watery planets with rocky cores," said Dalcanton. "We want to find atmospheres that have been shaped by the presence of life."

Dalcanton and the other authors of the new call-to-arms proposal imagine the HDST as the most powerful deep space telescope yet, using its massive mirror and other technological advancements to scan for, identify and document the presence of "planets that may be as much as 10 billion times fainter than their host star."

The new report was released in conjunction with a July 6 presentation and panel discussion hosted by the American Museum of Natural History.

"This is a chance to get people excited about something that could be their children's Hubble," Dalcanton concluded.