NASA’s 36-pixel sensor will revolutionize the study of outer space with X-rays

In a world such as ours, where some carry around camaras of up to 200 million pixels in their pockets, it’s a bit surprising that a recently launched outer space telescope doesn’t even remotely approach that metric. We’re talking about the news that NASA is collaborating with JAXA (Japan Aerospace Exploration Agency) in the development of a new X-ray image chip named Resolve for the XRISM satellite. The resolution it offers may come as a surprise.

The sensor features an astonishing 36 pixels — no, not megapixels — to carry out its work. Despite this low resolution, NASA affirms that the instrument has everything necessary to revolutionize the study of far-away X-rays. As such, it constitutes a great advancement in the study of outer space.

An important sensor for NASA, but also the rest of us

Resolve is the principal instrument aboard JAXA’s XRISM (X-Ray Imaging and Spectroscopy Mission) satellite, which was shot into space in September 2023. Since its launch, the two agencies have shared few updates on the mission, but recently, NASA revealed more details about its design and its equipment’s capabilities. The chip features an array of 6x6 pixels so large that they’re easy to spot. This is a quality-over-quantity situation, given that each pixel can take the universe’s temperature with a high level of precision.

The Resolve detector was invented and built at NASA’s Goddard Space Flight Center. It’s one of two instruments onboard the XRISM, the other being a more conventional X-ray CCD camara. “Resolve is more than a camara. Its detector takes the temperature of each X-ray that strikes it,” said Brian Williams, NASA’s XRISM project scientist at Goddard.

That means that each pixel is a “microcalorimeter spectrometer” that works independently and is capable of measuring tiny variations in heat. It’s so precise that scientists can use the X-ray spectrum to determine the composition of the object that emitted the energy and its motion in space. NASA says that a single pixel with a chip like this would be an important advance — and Resolve has 36. The spacecraft will use Resolve to study objects like supermassive black holes, supernova remnants and clouds of superheated gas within galaxy clusters.

Another great advance in the study of the universe

If NASA and JAXA have released few details about XRISM and Resolve, it’s important to keep in mind that the mission is programmed to take place over the course of two-and-a-half years. NASA believes that work with XRISM could lead to larger arrays of microcalorimeter pixels, possibly numbering in the hundreds or thousands.

NASA designed Resolve in order to observe X-rays with energy as low as 300 electronvolts (eV). However, a protective shutter aboard XRISM failed to retract, which has limited the instrument to measuring energies of 1,800 eV and above. Even so, the information it obtains is of vital importance for our understanding of the universe.

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