NASA has launched a telescope into space that is expected to discover around 100,000 new planets

Roman is set to study dark matter and dark energy, compile vast surveys of the Universe and potentially discover around 100,000 new exoplanets. Its main advantage lies not in having a larger mirror, but in its ability to scan vast swathes of the sky very quickly.

Details

Roman’s primary mirror has a diameter of 2.4 metres — the same as Hubble’s. However, its wide-angle infrared camera covers an area of the sky more than 100 times larger in a single image.

According to NASA estimates, Roman will be able to carry out some surveys approximately 1,000 times faster than Hubble.

It is precisely this capability that will allow the search for rare objects not one at a time, but amongst vast clusters of stars and galaxies.

There are particularly high expectations regarding exoplanets. NASA expects Roman to be able to detect around 100,000 planets using the transit method, by tracking a slight dip in a star’s brightness as a planet passes in front of it. A further thousand or so worlds may be found using gravitational microlensing.

This is a forecast, not a guaranteed number of future discoveries.

On board is also an experimental coronagraph, which blocks out the star’s bright light and allows much fainter objects near it to be seen. Its primary purpose is to test direct-observation technologies for large planets, rather than to search for a second Earth.

Roman will spend around three months in transit and during the system commissioning phase. The first images are expected in early 2027.

Why this is important

Hubble and James Webb are excellent for studying individual objects in detail, but their fields of view are relatively small. Roman was designed as a large-scale survey instrument.

During its main five-year mission, it is set to observe billions of galaxies and hundreds of millions of stars. Such surveys will help scientists investigate the distribution of dark matter and determine how the expansion rate of the Universe has changed under the influence of dark energy.

Roman is also significant for planetary research precisely because of its scale. Instead of studying just a few unusual systems, astronomers will obtain statistical data on a vast number of worlds in different parts of the Milky Way — ranging from Earth-sized planets to gas giants.

The history of the telescope itself is also interesting: its mirror originated from equipment transferred to NASA by the US National Reconnaissance Office. The optics were subsequently significantly redesigned for the scientific mission.

Source

Mission: Nancy Grace Roman Space Telescope.

Launch: 30 August 2026, SpaceX Falcon Heavy rocket, Kennedy Space Centre.