For what duration was the official primary mission set for both Spirit and Opportunity in Martian sols?
Answer
90 Martian sols.
The initial operational window established for both robotic geologists was a strictly defined, short-term assignment. The official primary mission duration for both Spirit and Opportunity was set for only 90 Martian sols, which equates to roughly three Earth months. Engineers designed and built the complex electronic and mechanical systems to function reliably for this limited time, banking on only a small statistical probability of extended operation. Successfully meeting the scientific checklist within this 90-sol window was the benchmark for validating the entire expensive exploration program, although both rovers vastly exceeded this initial operational goal.

Related Questions
What was the definitive proof sought by Spirit and Opportunity upon arrival in January 2004?Which Martian feature was Spirit tasked to examine by driving toward the rim of Bonneville Crater?What specific surface feature at Meridiani Planum prompted Opportunity's initial high-value inspection?For what duration was the official primary mission set for both Spirit and Opportunity in Martian sols?Which fundamental task relied on the Alpha Particle X-ray Spectrometer (APXS) instrument?What specific water-related minerals was the Miniature Thermal Emission Spectrometer (Mini-TES) instructed to look for?What was the core physical routine sequence defined for Spirit when analyzing a rock sample?What implied *type* of water environment was Spirit seeking, contrasted with Opportunity's focus?What role did the thorough initial success of the rovers upgrade them to, moving beyond proof-of-concept explorers?What mineral, typically forming in water on Earth, was indicated by spectral data at Opportunity's landing site?