It was a spy satellite, now NASA's new telescope is set to head into space

NASA's Nancy Grace Roman Space Telescope set to explore the universe This weekend, NASA plans to launch its next flagship mission into deep space. The Nancy Grace Roman Space Telescope, which started life as a spy satellite, will help find alien planets, map the universe, and possibly contribute to the collapse of a major theory in modern physics. Ami Choi, a research astrophysicist at NASA's Goddard Space Flight Center, says the telescope will help make discoveries in dark energy and dark matter. But, as previous space telescopes have done, it may find things that astronomers can't even imagine yet. "The unknown unknowns that we'll probably discover — I think that's also very exciting," Dr Choi says. If the launch goes to plan, the telescope will release its first images and data in about three months. And Australia will play a role beaming back the discoveries the telescope makes. New life for a spare spy satellite The $US4.3 billion ($6 billion) telescope, called Roman for short, is named after astronomer Nancy Grace Roman. Roman, dubbed the "Mother of Hubble", was the first chief of astronomy at NASA and a powerful advocate for space-based telescopes. The telescope is a souped-up version of one of two spy satellites donated by the US National Reconnaissance Office (NRO) to NASA in 2012. "It was a surprise to everyone when we heard that they just plonked on Goddard's doorstep," Brad Tucker, an astrophysicist at the Australian National University, says. Both satellites had been developed for observing the Earth, before cost overruns caused the NRO's project to be cancelled. To create Roman, NASA bolted some new instruments onto one of the satellites, including an infrared camera, and refitted it for flight into deep space. Despite cutting costs by using a hand-me-down satellite, Roman's launch was not a certainty, with the first Trump administration proposing its cancellation in 2018 and 2019. Benjamin Pope, an astrophysicist who was working at New York University at the time, was among hundreds of astronomers who travelled to the US capital to lobby against its cancellation. "People came from all over the United States, just go to Congress and say: 'This matters to us, this matters to our universities, this matters to our research, this matters to the public,'" Dr Pope, now at Macquarie University, says. The mission survived both proposed cancellations, and even another by the second Trump administration in 2025, and is now launching nine months ahead of schedule. "We're super lucky that despite all of the drama about its funding history and development history … everyone's really excited for Roman," Dr Pope says. What the Roman telescope is built to see The telescope's 2.4-metre mirror is the same size as the Hubble telescope and smaller than the James Webb Space Telescope (JWST), making it less powerful. But the Roman telescope has a wider field of view than either of the other space telescopes, meaning it can capture a bigger section of the sky in each snapshot. It's also designed to see in a different part of the light spectrum to the JWST, looking at visible and near-infrared light rather than further into the infrared. "It looks at colours that JWST really isn't looking at," Dr Tucker says. Once launched, the Roman telescope will head to the same part of space as JWST: Lagrange Point 2, or L2, some 1.5 million kilometres from Earth. Galactic panoramas to find dark matter The telescope is fitted with a 300-megapixel infrared camera which will capture large chunks of the sky in each exposure. "We consider it to be very powerful for surveys of the sky, or mapping out very large regions of the sky in very clear detail," Dr Choi,who is working on Roman's camera, says. These wide-angle shots are particularly useful for learning about two of the great mysteries in modern physics: dark matter and dark energy. Dark matter makes up most of the universe's matter, while dark energy is thought to be behind the universe's accelerating expansion, but physicists don't know what either phenomenon really is. Surveying large portions of the sky allows researchers to find things like supernovas, which can be used to measure the expansion of the universe. Observations from different telescopes are also important, because they can cross-check each other's results. Some other astronomical surveys are starting to suggest that current models of dark energy could be wrong. "We're really starting to see hints that dark energy is even funnier than we previously thought," Dr Tucker says. The Roman telescope is expected to help confirm, or refute, these findings, over its first five years of operation. Looking for alien planets Dr Pope, meanwhile, is excited by the telescope's other big objective: finding "exoplanets" orbiting other stars. "Roman may discover, over the course of its lifetime, many more planets than are currently known by all other telescopes and methods," Dr Pope says. Roman's second instrument, its coronagraph, is designed to block out light from stars, letting the telescope see fainter objects near those stars. While it won't quite be powerful enough to see small exoplanets like the Earth, Dr Pope says it will deliver unprecedented information on larger exoplanets — more like Jupiter in our solar system — including enough data to study their atmospheres. "Before the end of my career, I want us to be participating in discovering habitable worlds and understanding what they look like," Dr Pope says. "Roman is the biggest stepping stone towards that." West Australian antenna collecting the data Once the telescope is in position, it will beam back some 1.4 terabytes of data to Earth each day. One of the three places receiving this data is in Western Australia, at the newly-built European Space Agency antenna run by the CSIRO in New Norcia, 130km north-east of Perth. CSIRO site manager Suzy Jackson says the Roman telescope will transmit multiple times more data than other deep space satellites the station communicates with. "We've basically had to upgrade our comms links on the ground in order to support that, which is quite hilarious," she says. The station has to be operated with extreme precision, with parts of the 35-metre antenna being positioned to an accuracy of 0.5 millimetres. "We've got 700 tonnes of antenna and we've got to point that to an accuracy of hair-splitting in order just to hit the target at all," Ms Jackson says. "Everything's got to be absolutely perfect." When will the Roman telescope release its first pictures? The telescope is scheduled to launch from NASA's Kennedy Space Center in Florida at 7:26am US Eastern time (9:26pm AEST) this Sunday, August 30. Then, the telescope will take three months to travel to its deep space destination and go through commissioning tests and checks. If the launch and tests go to plan, Roman's first images will be publicly released three months after launch, and the telescope will begin its scientific observations. All of Roman's scientific data will be available for anyone to download, immediately after it's collected. "It's when you enable tonnes of different minds to look through data and do analysis and brainstorm — that's when you get all this interesting new information," Dr Choi says. Dr Pope says the telescope's "open skies" policy is exciting. "We're all going to be trying to drink from this fire hose of data," he predicts. "This is going to spur a lot of excitement, conflict, drama, technology — everything."