Old, as in ~2019~ 2013. It mentions four, not five mars rovers. So its from before 30. Juli 2020. It might have been writing during the fourth mission, so from

Old, as in ~2019~ 2013. It mentions four, not five mars rovers. So its from before 30. Juli 2020. It might have been writing during the fourth mission, so from 2004-2018 any date might be valid. But i would guess it is very new. Update: Appeared on HN in 2013.