JAXA, the Japanese space agency, is gearing up to launch two very different space missions from one rocket: a new X-ray telescope that will spy on some of the hottest places in our universe, and a small experimental robotic lunar lander.
The telescope is called X-ray Imaging and Spectroscopy Mission, or XRISM for short (pronounced like the word “chrisma”). The lunar mission is called Smart Lander for Investigating Moon, or SLIM. Here’s what you need to know about the launch.
When is the launch and how can I watch it?
XRISM and SLIM are expected to launch on Sunday at 8:26 p.m. Eastern Time from an H-IIA rocket from Japan’s Tanegashima Space Center (in Japan, it will be at 9:26 a.m. Monday). JAXA will provide a live stream in both Japanese and English on the agency’s YouTube channel starting at approximately 7:55 p.m. Eastern Time.
SLIM’s journey to the moon makes timing tight: There are only a few minutes each day when the Earth’s orientation is just right for the spacecraft to follow a trajectory that will take it into lunar orbit. Therefore, JAXA has a reserved launch window through Sept. 15, in case launch delays cause the mission to miss its launch window.
What is XRISM?
It’s a bus-sized telescope. JAXA is collaborating with NASA on the mission, with additional participation from the European Space Agency. XRISM will study cosmic X-rays, which unlike other wavelengths of light can only be detected from above the Earth’s atmosphere, protecting us from the harmful rays.
XRISM will use state-of-the-art spectroscopy to measure changes in the brightness of celestial bodies at different wavelengths. This data will reveal information about the motion and chemistry of some of the most extreme cosmic locations, such as the material swirling around black holes, the shimmering plasma that permeates galaxy clusters, and the remnants of exploding massive stars.
A key tool on board XRISM is Resolve, an instrument that collects spectroscopic data with a resolution far greater than X-ray observatories in orbit. Resolve must be cooled to just a fraction above absolute zero to measure small temperature changes when X-rays hit the surface of the instrument.
A second instrument called Xtend will work at the same time to image the cosmos at a resolution similar to how our eyes would perceive it if we had X-ray vision. As Resolve zooms in, Xtend zooms out, giving scientists additional images from the same X-ray sources over a larger area.
SLIM is a compact robotic lunar lander with no astronauts on board. It’s about the size of a small food truck and weighs more than 1,500 pounds at launch.
The lander’s mission is not primarily scientific. Rather, it is intended to demonstrate an accurate navigation system, which aims to land within approximately the length of a football field of an intended landing site. Developing better landing technology would enable future spacecraft to land closer to rugged terrain of scientific interest.
Where are XRISM and SLIM going?
The space telescope will be placed in orbit about 560 kilometers above the Earth. Once there, researchers will spend the next few months turning on the instruments and testing their performance. The scientific activities will start in January and the first results of this data are expected in about a year.
You’ll have to be patient with SLIM on his journey to the Shioli crater on the near side of the moon. The spacecraft will make a long detour of at least four months, requiring less propellant. SLIM will take several months to reach the lunar orbit, then orbit the moon for a month before attempting to surface.