GoKawiilGREENBELT, Md.—On Tuesday, NASA invited the press to look at the fully assembled Nancy Grace Roman Space Telescope, which is now ready to join the ranks of the great observatories in orbit, ahead of its September launch. The Roman Space Telescope (NGRST), named after a key figure in the planning of the Hubble Space Telescope, is notably distinct from hardware like the Hubble and Webb, as it’s designed around a wide-field view and massive imaging system that will allow it to send back 1.4 terabytes of data to Earth every day.
It also has an unusual history that began when NASA’s planning intersected with surplus spy hardware.
In from the cold
Many of the gases in our atmosphere absorb infrared wavelengths, contributing to the greenhouse effect that has helped keep the planet habitable for us. But that effect also makes infrared astronomy from Earth extremely difficult. That’s unfortunate, as a number of important phenomena, from the earliest galaxies to the features of exoplanet atmospheres, are only detectable at infrared wavelengths. There have been a number of infrared-specific telescopes put into space, notably the Spitzer, one of the original suite of Great Observatories.
But those telescopes were largely designed to provide high-resolution imaging of a tiny slice of the sky. There was also a call for a survey telescope capable of imaging large swaths of the sky simultaneously. In the infrared, this could do everything from revealing the large-scale structure of the early Universe to cataloging far more of the asteroids orbiting in Earth’s vicinity. NASA eventually adopted the idea as a priority in the form of WFIRST, the Wide Field Infrared Survey Telescope.
Around the same time, the National Reconnaissance Office decided that two of its spy satellites were surplus to requirements and offered the hardware to NASA. By the time the news broke, NASA had already recognized that the hardware could work for WFIRST. NASA’s Mark Melton told Ars that WFIRST designs at the time used a 1.5-meter telescope; the NRO hardware was almost twice that size. This required scaling up a lot of the hardware—the present NGRST easily extended past the second story of the building it was housed in—but it also provided higher-resolution imaging and more space for some of the imaging hardware.