The U.S. Naval Research Laboratory (NRL) and the Southwest Research Institute (SwRI) have partnered to study the sun’s outer corona with the goal of gaining a better understanding of how solar events affect Earth’s atmosphere and magnetic field. The ‘Polarimeter to Unify the Corona and Heliosphere’ (PUNCH) program is primarily funded by NASA.
“This mission really has two focuses,” said Robin Colaninno, Ph.D., an astrophysicist with NRL’s Space Science Division. “Trying to look at the creation of the solar wind from the corona and then also looking at the propagation of the coronal mass ejections in the solar wind.”
Punch will consist of four 40 kg, suitcase-sized microsatellites built by SwRI. Three of the space-craft will image the motion of the solar wind by imaging reflected polarized light from electrons in the wind. A fourth space-craft will directly image the outer corona using a special narrow field camera (Narrow Field Imager) built by the U.S. Naval Research Laboratory. Punch will also use much of the data being collected by NASA’s Parker Solar Probe mission, which is currently orbiting the sun closer than any previous spacecraft.
The mission will launch on a Pegasus rocket in August 2022 and will cost $165 million for all four spacecraft plus the launch. On the same launch will be the two TRACERS – Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites – built by Millenium Space Systems and will be used to study how the solar wind interacts with the Earth’s magnetic field at the North Pole.
“The vacuum of space between the planets is not completely empty — it is actually filled with a tenuous, hypersonic ‘solar wind’ that streams out from the corona and affects spacecraft and planets — including our own,” said PUNCH principal investigator Dr. Craig DeForest, a scientist and program director in SwRI’s Space Science and Engineering Division. “PUNCH will observe the ‘no-man’s land’ between the outer solar corona and the solar wind, giving us our first clear images of the entire system connecting the sun and Earth.”
In addition, the PUNCH satellites will track in 3D the sun’s coronal mass ejections, also known as “CMEs” or “space storms,” as they erupt from the corona out into interplanetary space. CMEs cause some “space weather” events that affect Earth, which can threaten astronauts, damage satellites, black out power grids, and disrupt communication and GPS signals.