Possibilities and limitations of thermal infrared detections of the Chelyabinsk progenitor and 2024 YR4 before Earth encounters

We investigate the feasibility of detecting decameter-scale objects on day-side trajectories in infrared wavelengths from space, prior to their close encounters with Earth. Specifically, we examine a 20-m object on a Chelyabinsk-progenitor orbit (Jan/Feb 2013) and the 60-m potentially hazardous asteroid 2024 YR4 (Nov/Dec 2024 & 2032) during their respective approaches to the Earth-Moon system. Considering the solar elongation constraints of the NEO Surveyor and NEOMIR missions (both located at L1), along with an assumed detection threshold of 100 μ Jy at 8 μ m , we find that both missions would be capable of detecting the objects - hours in advance with NEO Surveyor and several days ahead with NEOMIR. We also address limiting factors such as the elevated infrared sky background due to zodiacal dust emission and the high apparent motion of targets near Earth. Finally, we discuss the challenges associated with observing asteroids at low solar elongation and large phase angles, where we lack good-quality IR validation data. • Methods to detect decameter-scale objects well before they have a close Earth encounter. • Description of advantages for doing such observations from space (here L1). • The advantage of thermal infrared measurements over measurements at visible wavelengths. • Possibilities and limitations of IR observations from space. • We estimate that a 20-m object could be detected with a 0.5 m telescope in space, at mid-IR wavelengths, with a lead time of 5–10 days.