Meet the Spacecraft: PUNCH

Launching as a rideshare with NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer), NASA’s PUNCH (Polarimeter to Unify the Corona and Heliosphere) is made up of four 140-pound small satellites, each about 1 x 2 x 3 feet in size, which will be synchronized to serve as a single “virtual instrument” that spans the whole PUNCH constellation.

Three of the PUNCH satellites will each carry a Wide Field Imager, a heliospheric imager that reduces direct sunlight by over 16 orders of magnitude, which is like the ratio between the mass of a human and the mass of a cold virus. The Wide Field Imager will provide views from 18 to 180 solar radii (45 degrees) away from the Sun in the sky. The wide-field imaging optics are based on the design of Nagler eyepieces, which are known among observational astronomers for their clarity, low distortion, wide field, and achromatic focus.

The fourth PUNCH satellite will carry the Narrow Field Imager, a coronagraph that blocks out the bright light from the Sun to better see details in the Sun’s outer atmosphere, or corona. The coronagraph will have a field of view from 6 to 32 solar radii in the sky, and it will view the corona in both polarized and unpolarized light.

Every four minutes, each camera will collect three raw images through three different polarizing filters. In addition, each camera will take a clear (unpolarized) image every eight minutes, which will help calibrate the polarized images. The PUNCH mission will downlink data multiple times a day via ground-based antennas on Earth that are managed by the Swedish Space Corporation. Then, the data will be sent to the mission operations center at Southwest Research Institute (SwRI) in Boulder, Colorado, which will share it with the science operations center, also at SwRI.