As reported by engadget,
The goal is to look for evidence of something called inflation that would have happened less than a billionth of a billionth of a second after the big bang. Evidence for that would be in how galaxies are positioned in the universe, and SPHEREx will help scientists map them in 3D relative to each other. Then, they can study those maps for patterns that are potentially caused by inflation. At the same time, the instrument will help uncover how the first galaxies formed stars.
The space telescope will also look at stars in own galaxy for water ice and frozen organic molecules, the building blocks of life on Earth. The idea is that water ice attached to dust grains in gas clouds around galaxies. Stars form inside those clouds, and then planets form from the leftover material around them. “Ices in these disks could seed planets with water and other organic molecules,” NASA wrote. “In fact, the water in Earth’s oceans most likely began as interstellar ice.”
Prior to Phase C, the SPHEREx team had to complete a preliminary design review and prove to NASA that they could actually build it. The team will spend 29 months finalizing the design and building components, before entering the next phase when they’re assembled and tested. SPHEREx is scheduled to launch in a window between June 2024 and April 2025, if all goes to plan — which is not, of course, a given.