NASA's upcoming SPHEREx mission will have some similarities with the James Webb Space Telescope. But the two observatories will take dramatically different approaches to studying the sky.

The SPHEREx mission will be able to scan the entire sky every six months and create a map of the cosmos unlike any before. Scheduled to launch no later than April 2025, it will probe what happened within the first second after the Big Bang, how galaxies form and evolve, and the prevalence of molecules critical to the formation of life, like water, locked away as ice in our galaxy.

While telescope alignment continues, the James Webb Space Telescope's Mid-Infrared Instrument (MIRI) is still in cooldown mode. MIRI, which will be the coldest of Webb's four instruments, is the only instrument that will be actively cooled by a cryogenic refrigerator, or cryocooler. This cryocooler uses helium gas to carry heat from MIRI's optics and detectors out to the warm side of the sunshield. To manage the cooldown process, MIRI also has heaters onboard, to protect its sensitive components from the risk of ice forming. The Webb team has begun progressively adjusting both the cryocooler and these heaters, to ensure a slow, controlled, stable cooldown for the instrument. Soon, the team will turn off MIRI's heaters entirely, to bring the instrument down to its operating temperature of less than 7 kelvins (-447 degrees Fahrenheit, or -266 degrees Celsius).

In the meantime, after achieving alignment with the Near-Infrared Camera (NIRCam), Webb engineers have begun aligning the telescope to the remaining near-infrared instruments, a six-week process.