They knew they would last more than 90 days. 90 was just the number they picked ...

throwaway0a5e on Feb 17, 2021 | parent | context | favorite | on: NASA's Perseverance rover will attempt to land on ...

They knew they would last more than 90 days. 90 was just the number they picked for the "days before we can declare success" threshold. They weren't counting on 10yr.