NASA has selected two new science missions as part of its Small Explorer (SMEX) programme to go forward to full production and which will be launched on the same rocket together. PUNCH – the Polarimeter to Unify the Corona and Heliosphere mission will employ for micro-satellite-sized spacecraft to measure the outer part of the Solar corona which emits the solar wind. The four 40kg PUNCH spacecraft will be built by the Southwest Research Institute of San Andonio. Three of the spacecraft will image the motion of the solar wind by imaging reflected polarised light from electrons in the wind. A fourth spacecraft will directly image the outer corona using a special narrow field camera built by the US Naval Research Laboratory. The launch of the mission will take place in August 2022 and will cost US$165 million for all four spacecraft plus the launch.
2017 Total Solar Eclipse as seen from Oregon showing at least some of its concentrated magnetic field line structure (the poles appear to be top left to bottom right). Courtesy: NASA
On the same launch will be the two TRACERS – Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites – spacecraft worth US$110 million including the launch. The two TRACERS spacecraft will be built by Millenium Space Systems and will be used to study how the solar wind interacts with the Earth’s magnetice field at the North Pole – specifically at the magnetic cusp where the field lines bend down to the Earth’s surface, allowing the wind to reach the Earth’s atmosphere.
