The mission, called the Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx), will be a two-year affair to survey space in both the optical and infrared spectrum and gather data on 300 million galaxies and over 100 million stars within the Milky Way.
"This amazing mission will be a treasure trove of unique data for astronomers,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate. “It will deliver an unprecedented galactic map containing ‘fingerprints’ from the first moments in the universe’s history. And we’ll have new clues to one of the greatest mysteries in science: What made the universe expand so quickly less than a nanosecond after the big bang?”
To make its observations, SPHEREx will carry a 20cm optical telescope with a 3.5° x 7° field of view. All light imaged by those optics will be gathered by a 2k x 2k mercury cadmium telluride sensor array. Additionally, the mission will sport a near infrared imager capable of collecting data between the 0.75- to 5.0-micrometer wavelengths.
Though SPHEREx is the latest NASA mission to be announced, it isn’t without its precedents. The European Space Agency has its own optical and near infrared mission (Euclid) planned for 2022, and NASA has a complementary infrared space observatory (WFIRST) planned for the mid-2020s. Between these three missions, many of the more confounding mysteries in cosmology will be explored, including the origin and nature of dark matter and energy, and how many exoplanets orbit nearby and distant stars.
According to NASA the SPHEREx mission will cost $242 million not including launch expenses.
To put that into perspective, a single F-35 fighter costs between $94.3 and $122.4 million depending on the variant. Now, depending on how you value government spending, the SPHEREx mission might just be a tremendous value provided the mission makes it into space and does in fact help us understand why the universe is expanding.