On Thursday morning in Japan, a bus-sized telescope equipped with X-ray vision blasted off into space.
He wasn’t alone. Along for the ride was a robotic lunar lander about the size of a small food truck. The two missions – XRISM and SLIM – will soon separate, with one heading to spy on some of our universe’s hottest spots, and the other to help Japan’s space agency, JAXA, test technologies that will be used in larger-scale lunar exploration. decline in the future.
The lift-off from the shores of Tanegashima, an island in the southern part of the Japanese archipelago, was picturesque, as the Japanese H-IIA rocket soared over the remote launch site and disappeared into the blue sky with a few clouds. About 47 minutes into the flight, launch officials were seen on live video celebrating in mission control as the XRISM and SLIM spacecraft headed toward their disparate cosmic destinations.
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the X-ray imaging and spectroscopy mission – XRISM for short (pronounced like “chrism”) – is the primary passenger at launch. From an orbit 350 miles above Earth, XRISM will study exotic environments that emit X-ray radiation, including accretions of material orbiting black holes, scorching plasma permeating galaxy clusters, and the remnants of exploding massive stars.
Data from the telescope will shed light on the motion and chemistry of these cosmic sites using a technique called spectroscopy, which relies on changes in the brightness of sources at different wavelengths to extract information about their composition. This technique gives scientists a look at some of the highest energy phenomena in the universe and will add to the comprehensive multi-wavelength picture of the universe that astronomers have drawn.
XRISM spectroscopy “will reveal energy flows between celestial bodies at different scales” with unprecedented precision, Makoto Tashiro, the telescope’s principal investigator and an astrophysicist at the Japan Aerospace Exploration Agency, wrote in an email.
The Japanese Aerospace Agency is leading the mission in cooperation with NASA. The European Space Agency contributed to building the telescope, which means that part of the telescope’s observing time will be allocated to astronomers from Europe.
XRISM is a reconstruction of the Hitomi mission, a Japan Aerospace Exploration Agency (JAXA) spacecraft launched in 2016. The Hitomi telescope spiraled out of control weeks into its mission, and Japan lost contact with the spacecraft.
Brian J. said: “It was a devastating loss,” said Williams, an astrophysicist at NASA’s Goddard Space Flight Center who was on Hitomi’s team and is now an XRISM project scientist. The little data Hitomi had collected was a tantalizing taste of what a mission like this could offer.
“We realized we really had to build this mission again, because this is the future of X-ray astronomy,” Dr. Williams said.
Unlike other wavelengths of light, cosmic X-rays can only be detected from above Earth’s atmosphere, protecting us from harmful radiation. XRISM will join a large number of other X-ray telescopes already in orbit, including… NASA’s Chandra X-ray Observatorywhich launched in 1999, and NASA’s X-ray Polarimetry Explorer, which joined the party in 2021.
What sets XRISM apart from those tasks is an instrument called Resolve, which must be cooled to just a fraction above absolute zero so the instrument can measure tiny changes in temperature when X-rays hit its surface. The mission team expects Resolve’s spectral data to be 30 times more accurate than Chandra’s instruments.
Leah Corrales, an astronomer at the University of Michigan who was selected as a co-scientist for the mission, sees XRISM as a “groundbreaking vehicle” that represents “the next step in X-ray observations.” Through cutting-edge spectroscopy, Dr. Corrales will analyze the composition of interstellar dust to gain insight into the chemical evolution of our universe.
The high quality of data collected by XRISM spectroscopy may seem like a visit to these same extreme environments, said Jan-Uwe Ness, an astronomer at the European Space Agency who will manage the selection of proposals for Europe’s dedicated observing time.
“I’m looking forward to the spectroscopic revolution,” he said, adding that it will pave the way for more ambitious X-ray telescopes in the future.
XRISM also carries a second tool called Xtend which will work simultaneously with Resolve. As Resolve zooms in, Xtend will zoom out, providing scientists with complementary views of the same X-ray sources over a larger area. According to Dr. Williams, the Xtend is less powerful than the imager on the older Chandra telescope, which was built Some of the most striking views of the X-ray universe To go on a date. But Xtend will image the universe with a resolution similar to the way our eyes would perceive it if we had X-ray vision.
Once XRISM reaches low Earth orbit, researchers will spend the next few months operating the devices and conducting tests of their performance. Dr. Tashiro said scientific operations will begin in January, but initial data-driven studies may not appear for a year or more. Before any discoveries, he was excited to see the instruments in operation, adding: “We will certainly see the new world of X-ray astronomy once they are operational.”
More than anything else, Dr. Williams is looking forward to the “unknown unknowns” that XRISM might discover. “Every time we launch a new capability, we discover something new about the universe,” he said. “What will this be? I don’t know, but I’m excited to find out.”
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The Lunar Exploration Intelligent Lander, or SLIM, is the next robotic spacecraft headed to the Moon but may not be the next to land.
SLIM will make a long indirect flight of at least four months and require less propellant. The lander will take several months to reach lunar orbit, and then it will spend a month orbiting the moon before attempting to land on the surface near Sciuli crater on the moon’s near side.
This means that two American spacecraft, made by Astrobotic Technology in Pittsburgh and Intuitive Machines in Houston, which may launch later this year and will take more direct paths to the Moon, could overcome SLIM on the surface.
Although SLIM carries a camera that can identify the composition of the rocks around the landing site, the mission’s primary goals are not scientific. Rather, it is a demonstration of a precise navigation system, aiming to land at a distance equal to the length of a football field at the target location.
Currently, lunar landers can attempt to land several miles away from the designated landing site. For example, the landing zone for India’s Chandrayaan-3 spacecraft, which last month became the first to successfully land in the moon’s south polar region, was seven miles wide and 34 miles long.
The vision-based systems on many landers are limited because space-hardened computer chips have only about one-hundredth the processing power of the best chips used on Earth, the Japan Aerospace Exploration Agency said in its press kit.
For SLIM, the Japan Aerospace Exploration Agency has developed image processing algorithms that can run quickly on slower space chips. As SLIM approaches landing, the camera will help guide the spacecraft’s descent to the lunar surface; Radar and lasers will measure the spacecraft’s altitude and descent speed.
Due to the collision risks that come with current systems, lunar landers are typically directed to flatter, less interesting terrain. A more accurate navigation system would enable future spacecraft to land near rugged terrain of scientific interest, such as craters containing frozen water near the moon’s south pole.
At launch, the SLIM weighed over 1,500 pounds; More than two-thirds of the weight is propellant. By contrast, India’s lunar lander and its small rover weighed about 3,800 pounds, and its accompanying propulsion module that propelled the two out of Earth’s orbit toward the moon added 4,700 pounds.
