NASA's anticipated Roman Space Telescope, with a field of view 100 times larger than Hubble's, will measure light from a billion galaxies, microlens observations deep within the Milky Way to discover thousands of exoplanets, monitor hundreds of millions of stars, and observe distant galactic neighbors in what may be the greatest discovery so far this century.
NASA has updated details of the epic mission, which could begin as early as October 2026, 16 years after conceptual approval during the 2010 National Research Council Decadal Survey and 10 years after the development green light in February 2016.
The planet hunter, formerly known as the Wide Field Infrared Survey Telescope (WFIST), has entered Phase C of construction, which is final design and manufacturing. NASA's launch target is October 2026, but the window can be extended to May 2027.
"We're using the entire scientific community to lay the groundwork, so when we launch, we'll be able to do strong science right out of the gate," said Julie McEary, Roman senior project scientist at NASA's Goddard Space Flight Center in Maryland. "There's a lot of exciting work to be done, and scientists can get involved in a lot of different ways."
The Roman Telescope is named after Nancy Grace Roman, the pioneering American astronomer who, among her many achievements, played a key role in the development of the Hubble Space Telescope at a time when opportunities for women to hold senior positions in science were severely hampered.
While the pioneering astronomer wouldn't be there to witness this new era of space exploration - she died on Christmas Day 2018 at the age of 93 - it's still a very fitting tribute.
"Roman will be an incredible machine of discovery, combining a vast view of space with keen vision," McEnery said. "Its time-domain measurements will yield a treasure trove of new information about the universe."
Its primary mirror is 2.4 meters (7.9 feet) wide, the same size as the Hubble Space Telescope's, but only one-fifth as heavy and has a field of view 100 times larger than its predecessor.
A recent study by the Kepler Space Telescope focused on stars at the edge of the Milky Way, while the Roman Telescope will travel to the center of the Milky Way to conduct a time-domain survey of the Milky Way Bulge, using infrared vision to penetrate dust clouds and observe the central region of the Milky Way. There, it will look for microlensing events, where previously unknown exoplanets can be discovered (so to speak) by observing apparent gravitational "distortions." Because of the density of stars in the region, scientists expect to see more than 50,000 microlensing events, revealing "rogue" planets, black holes, neutron stars and trans-Neptunian objects.
According to the current plan, Roman will film every 15 minutes for about two months. Over the first five years of the mission, the images will be repeated six times, adding up to more than a year of observation time.
Scott Gaudi, professor of astronomy at Ohio State University, said: "This will be the longest exposure of the sky ever. In terms of planets, it will cover most of the unknown territory." Astronomers believe the survey will also discover more than 1,000 planets orbiting in systems far from their host stars, farther from Earth than any previous mission.
If the Lohmann telescope's first deep dive into space wasn't enough, it will also discover more than 1,000 neutron stars and hundreds of stellar-mass black holes. Astronomers will also use the Milky Way Photographer to find thousands of Kuiper Belt objects, the icy objects scattered mostly beyond Neptune.
The Roman Space Telescope will rely on two key components to collect data. The Wide Field Instrument (WFI) provides wide field imaging and spectroscopy, ideal for cosmology and exoplanet surveys, while the Coronagraph Instrument (CGI) will focus on high contrast imaging and spectroscopy for observing exoplanets and debris disks.
Scientists are also studying how advances in machine learning will help analyze the trillions of images Roman has collected.
"The preparation is very complex, partly because everything Roman does is interconnected," McEnery said. "Each observation will be used by multiple teams for different science cases, so we are creating an environment that makes it as easy as possible for scientists to collaborate."