Satellite to study ‘rainbow’ of X-rays to launch in August

WASHINGTON: A new space mission led by the JAXA (Japan Aerospace Exploration Agency), aims to probe high-energy light into the equivalent of an X-ray rainbow.

The satellite called XRISM (X-ray Imaging and Spectroscopy Mission, pronounced “crism”) is scheduled to launch from Japan’s Tanegashima Space Center on August 25.

XRISM’s instrument called Resolve will probe the high-energy light.

“Resolve will give us a new look into some of the universe’s most energetic objects, including black holes, clusters of galaxies, and the aftermath of stellar explosions,” said Richard Kelley, NASA’s XRISM principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in a statement.

“We’ll learn more about how they behave and what they’re made of using the data the mission collects after launch,” Kelley added.

Resolve is an X-ray microcalorimeter spectrometer instrument collaboration between NASA and JAXA. It measures tiny temperature changes created when an X-ray hits its 6-by-6-pixel detector. To measure that minuscule increase and determine the X-ray’s energy, the detector needs to cool down to around minus 270 Celsius, just a fraction of a degree above absolute zero.

The instrument reaches its operating temperature after a multistage mechanical cooling process inside a refrigerator-sized container of liquid helium. By collecting thousands or even millions of X-rays from a cosmic source, Resolve can measure high-resolution spectra of the object.

Spectra are measurements of light’s intensity over a range of energies. Prisms spread visible light into its different energies, which we know better as the colours of the rainbow.

Scientists used prisms in early spectrometers to look for spectral lines, which occur when atoms or molecules absorb or emit energy. Now astronomers use spectrometers, tuned to all kinds of light, to learn about cosmic objects’ physical states, motions, and compositions.

Resolve will do spectroscopy for X-rays with energies ranging from 400 to 12,000 electron volts by measuring the energies of individual X-rays to form a spectrum. (For comparison, visible light energies range from about 2 to 3 electron volts.)

“The spectra XRISM collects will be the most detailed we’ve ever seen for some of the phenomena we’ll observe,” said Brian Williams, NASA’s XRISM project scientist at Goddard, in a statement.

“The mission will provide us with insights into some of the most difficult places to study, like the internal structures of neutron stars and near-light-speed particle jets powered by black holes in active galaxies.”

The mission’s other instrument, developed by JAXA, is called Xtend.

It will give XRISM one of the largest fields of view of any X-ray imaging satellite flown to date, observing an area about 60 per cent larger than the average apparent size of the full Moon.


Resolve and Xtend rely on two identical X-ray Mirror Assemblies developed at Goddard. The XRISM mission also has participation by ESA (European Space Agency) and the Canadian Space Agency.