2023-07-20 16:12:57
The XRISM satellite, shown here in an illustration, is an X-ray mission that will study some of the most energetic objects in the universe.
Credits: NASA Goddard Space Flight Center Conceptual Imaging Laboratory
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A new satellite called the X-ray Spectroscopy and Imaging Mission (XRISM, pronounced “crism”) aims to separate high-energy light into the equivalent of an X-ray rainbow. The mission, led by the Japan Aerospace Exploration Agency (JAXA), will do this using an instrument called Resolve.
XRISM is scheduled to launch from Japan’s Tanegashima Space Center on August 25, 2023 (August 26 in Japan).
“Resolve will give us new insight into some of the most energetic objects in the universe, including black holes, galaxy clusters, and the aftermath of stellar explosions,” said Richard Kelley, principal investigator for NASA’s XRISM mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “With this we will learn more about how these objects behave and are made of, using the data that the mission collects after launch.”
The Resolve instrument is an X-ray microcalorimeter spectrometer, developed in collaboration between NASA and JAXA. This instrument measures the tiny changes in temperature that occur when an X-ray strikes its 6-by-6-pixel sensor. To measure that minuscule rise and determine the energy of the X-rays, the detector needs to cool to around minus 270 degrees Celsius (minus 460 degrees Fahrenheit), just a fraction of a degree above absolute zero.
The instrument reaches its operating temperature after a multi-stage mechanical cooling process inside a refrigerator-sized container of liquid helium.
This image shows the detector of the Resolve instrument aboard the XRISM satellite.
Credits: NASA/XRISM/Caroline Kilbourne
By collecting thousands or even millions of X-rays from a cosmic source, Resolve can measure the high-resolution spectra of the object. Spectra are measurements of the intensity of light over a range of energies. Prisms spread visible light into its different energies, which we know better as the colors of the rainbow. Scientists have used prisms in early spectrometers to look for spectral lines, which are produced when atoms or molecules absorb or emit energy.
Now, astronomers use spectrometers, tuned to all kinds of light, to learn about the physical states, motions, and compositions of cosmic objects. Resolve will perform spectroscopy of X-rays having energies ranging from 400 to 12,000 electron volts by measuring the individual energy of the X-rays to form a spectrum. (For comparison, the energies of visible light range from about 2 to 3 electron volts.)
“The set of XRISM spectra will be the most detailed we’ve ever seen for some of the phenomena we’ll be looking at,” said Brian Williams, NASA XRISM project scientist at Goddard. “This mission will provide us with information about some of the most difficult places to study, such as the internal structures of neutron stars and the near-light speed particle jets that are fueled by black holes in active galaxies.”
This image shows the detector of the Resolve instrument aboard the XRISM satellite.
Credits: NASA/XRISM/Caroline Kilbourne
The other mission instrument, developed by JAXA, is called Xtend. This instrument will give XRISM one of the largest fields of view of any X-ray imaging satellite launched to date, allowing it to observe an area approximately 60% larger than the average apparent size of the full Moon.
Resolve and Xtend rely on two identical sets of X-ray mirrors developed at the Goddard facility.
XRISM is a collaborative mission between JAXA and NASA, with the participation of ESA (European Space Agency). NASA’s contribution includes the scientific participation of the Canadian Space Agency.
Jeanette Kazmierczak
NASA Goddard Space Flight Center, Greenbelt, Maryland
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