A Falcon 9v1.2 Block 5 rocket successfully launched the IXPE – Imaging X-ray Polarimetry Explorer mission for NASA on 8 December 2021. The launch took place at 0600 GMT from the former Space Shuttle Pad 39A in Cape Canaveral. The reusable first stage B1061 (on its fifth flight) was safely recovered with a landing on the drone ship Just Read The Instructions stationed in the Atlantic Ocean, approximately 652km downrange. The fairing halves were also successfully recovered from the sea.
The launch required a significant and propellant consuming inclination change manoeuvre after a parking orbit had been achieved in order to reduce the 28.5 degree inclination change caused by a due East launch from Canaveral. The IXPE spacecraft was released into a near zero inclined 540 km low Earth orbit. This equatorial orbit was chosen to avoid the high radiation “South Atlantic Anomaly” which could have affected the spacecraft’s instrumentation.
This NASA two-year mission under Small Explorer programme uses 330 kg astronomical telescope-carrying spacecraft built by Ball Aerospace which is designed to measure the polarisation of cosmic X-rays from astronomical sources in the sky. These include black holes, pulsars, quasars and neutron stars. IXPE’s payload is a set of three identical imaging X-ray polarimetry systems mounted on a common optical bench and co-aligned with the pointing axis of the spacecraft. Each system comprises a 4-meter focal length mirror module assembly that focuses X-rays onto a polarization-sensitive imaging detector. NASA mission under Small Explorer programme. IXPE spacecraft carries three X-ray mirror modules at end of 4m boom to direct X-ray light onto a set of three X-ray detectors built by Italian Space Agency (ASI) in the main body of the satellite. IXPE will measure the polarization of high-energy cosmic X-rays and thus image black holes, neutron stars and pulsars.
Originally planned for a launch in 2020 by the expensive Pegasus small launch vehicle, budget constraints resulted in a change of launch vehicle to a Falcon 9 in April 2021 The launch was then further delayed by spacecraft construction delays brought on by the Covid-19 coronavirus pandemic.
NASA’s IXPE mission is probing the polarisation of space objects. Courtesy: NASA
