NASA Ready to Begin Building Sky-Mapping SPHEREx Telescope
NASA has been planning for the upcoming SPHEREx mission since early 2019, and it just reached an important milestone: it’s time to start building it. NASA says all the planning work is done, and the sky-mapping telescope’s design has been confirmed down to the smallest detail. When it finally makes it into space, SPHEREx will scan the entire sky to tell us about the earliest phases of the universe.
SPHEREx is part of NASA’s medium-class Explorers program, along with missions like the Transiting Exoplanet Survey Satellite (TESS) and the Ionospheric Connection Explorer (ICON) that monitors Earth’s atmosphere. When all’s said and done, SPHEREx (which stands for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) could cost NASA almost half a billion dollars, but that’s nothing compared to more complex telescopes like the new James Webb Space Telescope, which is coming up on $10 billion.
NASA currently plans to launch SPHEREx with the aid of a SpaceX Falcon 9 rocket. It will operate for 25 months, following a polar orbit around Earth. This will allow it to scan the entire sky four times with its lone instrument, a spectrophotometer with a tiny 8-inch primary mirror. Webb, on the other hand, has a record-setting 6.5-meter (21-foot) mirror. SPHEREx is designed to collect infrared data from large areas of the sky rather than focusing on individual targets like Webb will. That’s how it can see 100 percent of the sky in just a few years while Hubble observed only 0.1 percent of it in more than three decades.
SPHEREx will explore three astrophysical questions, including the origin of the universe, the formation of galaxies, and the abundance of water ice (it’s all crammed into the acronym-friendly name). It will scan the sky in 96 different color bands, giving astronomers a map that includes nearby younger galaxies as well as objects billions of light years away from the early universe. This could be of great value to astronomers the world over.
Having now completed the critical design review (or CDR as the agency calls it), NASA is ready to move from simulations to real hardware. COVID may have slowed the project down, but not even a pandemic stops the onward march of science. The mission could launch as soon as June 2024, but it could be as late as April 2025.