Authors: N. Lugaz (UNH), T. M. Salman (UNH, GMU), B. Zhuang (UNH), N. Al-Haddad (UNH), C. Scolini (UNH), C. J. Farrugia (UNH), R. M. Winslow (UNH), C. Möstl (IWF), W. Yu (UNH), E. Davies (UNH), F. Regnault (UNH), A. B. Galvin (UNH)

A coronal mass ejection (CME) erupted on 2021 February 20 and impacted both the STEREO-A and the Wind spacecraft, which were separated longitudinally by 55°. This makes this one of the widest reported multispacecraft detections of a magnetic ejecta for spacecraft near 1 au. The CME is found to propagate between STEREO-A and Wind around E34. At STEREO-A, the measurements indicate the passage of a moderately fast (~425 km s^-1) shock-driving ME, occurring 2-3 days after the end of a high speed stream (HSS). At Wind, the measurements show a faster (~490 km s^-1) and much shorter ME, not preceded by a shock nor a sheath, and occurring inside the back portion of the HSS. The ME orientation measured at both spacecraft is consistent with a passage close to the legs of a curved flux rope. We discuss the consequence of these measurements on our understanding of the CME shape and extent and the lack of clear signatures of the interaction between the CME and the HSS. We also discuss how the return of STEREO-A towards the Sun-Earth line in 2023 will allow for 1-2 years of multi-spacecraft measurements of CMEs and will occur in a time of increased solar activity as compared to 2007-2008 (the last time STEREO-A was in proximity of L1). Lastly, we argue that dedicated measurements with two or more spacecraft are needed to advance our understanding of CMEs, but also interplanetary shocks and corotating streams.