In October 2020, the European Space Agency (ESA) unexpectedly cancelled the ESA Medium Class M5 mission candidate SPICA (SPace Infrared telescope for Cosmology and Astrophysics), withdrawing it from the M5 competition just months before the Mission Selection Review process was due to start for the final three candidates.

The manner in which SPICA was cancelled shocked not only the SPICA Consortium comprising hundreds of astronomers and engineers, but also the general astronomical community beyond those directly involved in SPICA. An open letter with nearly 300 signatures was sent to the Director of Science at ESA, calling for more transparency in decision-making processes at ESA. An abridged version of the letter was submitted to Nature, and a further edited version was published in Nature on 24 November 2020.