Accessible does not mean exploitable: HiPERCAM reveals the ultra-fast rotation of 2022 OB$_5$

TL;DR

This study characterizes the ultra-fast rotating near-Earth asteroid 2022 OB$_5$ using high-cadence multiband photometry, revealing its rapid rotation and challenging surface operation feasibility despite its orbital accessibility.

Contribution

First photometric characterization of 2022 OB$_5$, demonstrating its ultra-fast rotation and discussing implications for asteroid resource exploration and mission planning.

Findings

Rotation period of 1.542 minutes confirmed by multiple observations.

Reflectance spectrum is featureless and moderately red, consistent with X-complex.

Ultra-fast rotation poses practical challenges for surface operations.

Abstract

2022 OB$_5$ is a sub-10-metre Apollo-type near-Earth asteroid whose orbital configuration placed it among the most dynamically accessible small bodies in near-Earth space, motivating its selection as the target of the first commercial asteroid-prospecting mission. We present its first photometric characterisation, based on high-cadence simultaneous five-band $u_sg_sr_si_sz_s$ observations obtained with HiPERCAM at the 10.4-m Gran Telescopio Canarias (GTC). Analysis of the light curves yields a rotation period of $P_{\rm rot} = 1.542 \pm 0.001$ min, independently confirmed with observations taken by the Two-meter Twin Telescope, establishing 2022 OB$_5$ as an ultra-fast rotator. The reflectance spectrum derived from the simultaneous multiband photometry is featureless and moderately red, consistent with the X-complex. Despite its good orbital accessibility, the ultra-fast rotation of 2022 OB$_5$ poses severe practical challenges for any surface operation with current technology, regardless of compositional interest. This illustrates a population-level challenge: at the sizes and $\Delta v$ values most favourable for in-situ missions, fast rotation is the dominant spin state, and rotation period measurement is therefore an indispensable prerequisite for evaluating the resource potential of asteroid mission candidates.