SpaceX Launches SPHEREx and PUNCH for NASA

Last night, March 11 local, SpaceX launched a pair of NASA science missions that will explore the infrared universe and study the solar wind.

The SpaceX Falcon 9 lifted off from Vandenberg Space Force Base in California at 11:10 p.m. Eastern. It placed into sun-synchronous orbits the Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) spacecraft and the four satellites of the Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission. All five spacecraft were in contact with controllers and functioning as expected after launch, the agency stated.

SPHEREx may sound familiar because I did a post about this mission at the end of January, about six weeks ago, and used this picture. 

NASA’s SPHEREx space observatory was photographed at BAE Systems in Boulder, Colorado, in November 2024 after completing environmental testing. The spacecraft’s three concentric cones help direct heat and light away from the telescope and other components, keeping them cool. Credit: BAE Systems

SPHEREx is what's called a NASA medium Explorer-class mission that will perform an all-sky infrared spectroscopic survey imaging the sky in 102 wavelength bands from 0.75 to 5 microns.  The unique-looking telescope with the three cones create a wide-field telescope with a diameter of 20 centimeters.  The spacecraft will be able to complete a single scan of the entire sky in six months.  The overall cost was $488 million.

“Even though SPHEREx uses a small telescope, it looks at the universe in a new way,” said Jaime Bock, principal investigator for the mission at Caltech, during a briefing in January about the mission. “This new capability allows us to address some of the most compelling questions in astronomy.”

Those questions fall into three key themes: studying the early universe, including the era of cosmic inflation immediately after the Big Bang; the formation and evolution of galaxies through the history of the universe; and measurements of water and organic materials in the Milky Way galaxy.

PUNCH, the other mission, has had virtually zero coverage here.  As the first quoted paragraph mentioned, PUNCH is a constellation of four small (64-kg or 141 lb) satellites meant to study the sun.  Three of the four carry wide-field imagers to observe the sun while the fourth has a narrow-field imager.  The mission's goal is to conduct the first three dimensional models of the sun's corona.  

The four spacecraft will work in conjunction, taking images of the sun using different polarizing filters as well as unpolarized images. Scientists will use the images to construct three-dimensional maps of the corona to study how it transitions into the solar wind and the effects of events like coronal mass ejections, or CMEs, from the sun that can create space weather events at Earth.

“The PUNCH scientists hope to better understand the entire inner solar system from the sun, through the corona, out into the inner solar system, and how that material impacts Earth,” said Nicholeen Viall, PUNCH mission scientist at NASA’s Goddard Space Flight Center, at that briefing.

The four PUNCH smallsats will orbit the Earth to perform three-dimensional mapping of the solar corona.  Reminder of the standard disclaimers: not to scale, artist's concept and all that.  Image Credit: NASA

Dr. Viall says that “The sun is never quiet.  It’s constantly having little explosions. So, even when there’s not a big space weather event, even when there’s not a big CME, there’s still little events that constantly bombard our Earth. PUNCH is the first instrument to have the sensitivity and the resolution to be able to see that daily space weather.”

It has long been my belief from my ham radio experiences that the big events don't always have the same effects, so we must be missing something else going on around the same times.  One day with a planetary geomagnetic index Kp=3 can be different from another with all the indices the same - or so it seems.  Watching the space weather forecasts can make you realize just how good the terrestrial weather forecasts are.  I'm looking forward to seeing if they get better. 

There's more coming this weekend.   Another heliophysics mission, a trio of smallsats called Electrojet Zeeman Imaging Explorer (EZIE) to study the aurora, will launch on the SpaceX Transporter-13 rideshare mission scheduled for as soon as March 15 at 2:39 AM EDT, also from Vandenberg SFB.