Spy agency behind NASA’s next big observatory

With the James Webb Telescope up and running, the astronomical community now eagerly awaits the launch of NASA’s next major space observatory. The Nancy-Grace-Roman telescope, whose hubs once belonged to a spy agency, is currently being overhauled. Once operational, its main purpose will be to discover new exoplanets. It will also aim to unravel two of astrophysics’ biggest mysteries: dark matter and dark energy.

A new large observatory behind the scenes

At first it looked like the mission would never happen. In the early 2000s, scientists from NASA and the Department of Energy both proposed a new observatory to investigate the outer reaches of the cosmos. Eventually, most of the available funds were allocated to the development of what would become the James Webb Telescope. The project was therefore shelved.

Everything then accelerated in 2011 with an unexpected surprise. In an upstate New York warehouse run by the National Reconnaissance Office was the organization responsible for building and operating spy satellites for the NSA and CIA. two mirrors similar to the Hubble telescope. Naturally, the NRO had no need for it. The agency therefore offered them to NASA.

Although the actual cost of these mirrors represents only a small fraction of the total budget for a space mission of this magnitude, this unexpected gift will have helped generate support for this project, which from then on received a first official name: The Wide Field Infrared Space Telescope, or WFIRST. Recently, the observatory was renamed Nancy-Grace-Roman in honor of NASA’s first female manager, Nancy Roman. Died in 2018, this woman scientist had paved the way for large space telescopes, and Hubble in particular.

Nancy-Grace-Roman wants a mirror the size of Hubble’s, but it will give a much wider field of vision. The observatory will help astronomers to better understand the evolution of our universe, shaped by dark matter and dark energy, and to dig hundreds of new planets.

In terms of exoplanetary research, the observatory will use an innovative trick known as gravitational microlensing.

The principle of a gravitational microlens

Microlensing occurs when light from distant background stars is temporarily amplified when a planetary system passes close to our line of sight. That is, if another object when observing a star crosses the line of sight to that star, the background light will briefly increase in brightness due to the curvature of the light around the intermediate object. Depending on the data returned, astronomers will then be able to characterize these exoplanets.

Principle for the detection of a planet using the gravitational microlensing method. Credit: Wikipedia

Note that the microlensing technique is not very effective at identifying planets orbiting close to their stars. Also, Nancy-Grace-Roman will focus on distant orbiting planets analogous to the gas and ice giants in our system. Since we believe that all water on Earth-like worlds comes from the outer regions of planetary systems, this observational work will be crucial to understanding the origins of life.

The observatory will also have another trick up its sleeve: a coronagraph. The latter will allow it to block the light from nearby stars and directly image all the exoplanets that surround it.

On the calendar side, NASA has set its sights on SpaceX. The launch will be with one Falcon Heavy rocket in October 2026. Once in space, the observatory will be positioned around the Lagrange 2 point, just like the James Webb telescope. Its primary mission is to last five years.

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