Some time later this summer, it is predicted, the National Academy of Sciences will release its long-awaited Decadal Survey for astrophysics, which is expected to recommend the science and architecture that NASA should embrace for its next “Great Observatory.”
Many Worlds earlier featured one of the four concepts in the running — LUVOIR or the Large UV/Optical/IR Surveyor. With a segmented mirror potentially as wide as 50 feet in diameter, it would revolutionize the search for habitable exoplanets and potentially could detect one (or many) distant planets likely to support life.
Proposed as a “Great Observatory” for the 2030s in the tradition of the Hubble Space Telescope and the James Webb Space Telescope (scheduled to launch later this year), LUVOIR would allow for transformative science of not only exoplanets but many other fields of astronomy as well.
Also under serious consideration is the Habitable Exoplanet Observatory, HabEx, which would also bring unprecedented capabilities to the search for life beyond Earth. Its mirror would be considerably smaller than that proposed for LUVOIR and it would have fewer chances to find an inhabited world.
But it is nonetheless revolutionary in terms of what it potentially can do for exoplanet science and it could come with a second spacecraft that seems to be out of science fiction, designed to block out starlight so exoplanets nearby can be observed. That 52-meter (or 170-foot) petal-rimmed, light-blocking disc is called a starshade or an occulter, and it would fly 76,600 kilometers (or 47,000 miles) away from the HabEx spacecraft and would work in tandem with the telescope to make those close-in exoplanet observations possible.
While the capabilities of HabEx are fewer compared to LUVOIR and the potential harvest of habitable or inhabited planets is less, HabEx nonetheless would be cutting edge and significantly more capable than the Hubble Space Telescope in nearly every way, while also being less expensive than LUVOIR and requiring less of a technology reach.
Scott Gaudi, an Ohio State University astronomer, was co-chair of the NASA-created team that spent three years studying, engineering and then proposing the HabEx concept. He put the potential choice between HabEx and LUVOIR this way: “Do you want to take a first step or a first leap? HabEx is a major step; LUVOIR is a huge leap.”… Read more