The Mecha repair tasks that Ji Xinghe received starting tonight exactly as the same time as Shen Mu since those damaged Mechas would only be transported at night.
The vehicular procession could likely be spotted during the day, so they travel at night without headlights, just using night vision equipment. There are almost no obstacles on the barren surface of the alien planet, and their unique environment allows any residual tracks from their night transport to disappear by daylight.
If the transportation distance was too long to cover in one night, the convoy would find a place to hide and wait out the day, then resume their journey when night fell on the alien planet. Ji Xinghe and his team were able to travel during the day because their target is small and their convoy carries special interference and stealth devices.