Japan and NASA are collaborating on a mission to observe the universe in X-rays, a type of light that reveals some of the most energetic and mysterious phenomena in the cosmos. The mission, called XRISM (X-ray Imaging and Spectroscopy Mission), is expected to launch soon from Japan’s Tanegashima Space Center.
What is XRISM and what will it do?
XRISM is a satellite that carries two instruments: Resolve and Xtend. Resolve measures the energy of each individual X-ray photon, providing information about its source, such as its composition, motion, and physical state. Xtend provides a wide-field view of the X-ray sky, observing an area about 60% larger than the average apparent size of the full Moon.
XRISM will use these instruments to study some of the hottest regions, largest structures, and objects with the strongest gravity in the universe. For example, XRISM will investigate:
- The aftermath of stellar explosions, such as supernovae and gamma-ray bursts, which produce heavy elements and shape the evolution of galaxies.
- The near-light-speed particle jets launched by supermassive black holes in the centers of galaxies, which can affect the surrounding environment and influence galaxy formation.
- The hot gas that fills the space between galaxies, which contains clues about the origin and fate of the universe.
XRISM will also explore other phenomena that emit X-rays, such as neutron stars, pulsars, binary systems, active galactic nuclei, galaxy clusters, and more. By observing these sources in X-rays, XRISM will reveal new aspects of their nature and behavior that are invisible to other types of telescopes.
How does XRISM capture X-rays?
X-rays are very energetic and can penetrate most materials. This makes them useful for medical imaging and security scanning, but also challenging for astronomical observations. Unlike visible, infrared, and ultraviolet light, X-rays cannot be focused by conventional dish-shaped mirrors. Instead, XRISM uses nested curved mirrors turned on their sides, which reflect X-rays at a shallow angle.
XRISM has 3,200 individual mirror segments in two mirror assemblies. These mirrors are coated with gold to enhance their reflectivity for X-rays. The mirrors direct the X-rays to the detectors at the end of a 6-meter-long (20-foot-long) extendable optical bench. The detectors convert the X-rays into electrical signals that can be processed and analyzed by computers.
What is the status and schedule of XRISM?
XRISM is a joint mission between JAXA and NASA, with participation from ESA and CSA. The mission was originally planned to launch in 2020, but was delayed due to technical issues and the covid-19 pandemic. The launch is now scheduled for Sunday night (August 27), aboard a H-IIA rocket from Japan’s Tanegashima Space Center.
The launch will also include an experimental lunar lander called SLIM (Smart Lander for Investigating Moon), which is designed to demonstrate a pinpoint landing on the Moon within 100 meters (328 feet) of a target location. This technology could enable future exploration of lunar sites of scientific interest.
After launch, XRISM will take about two months to reach its final orbit around Earth, at an altitude of about 600 kilometers (370 miles). The satellite will then undergo several months of calibration and testing before starting its scientific observations. The mission is expected to operate for at least three years.
