NASA’s twin rovers Spirit and Opportunity are celebrating their fifth birthdays on Mars after surviving more than 20 times their expected lifespan, Space.com reports. The two probes were each built for a 90-day trek across the Red Planet but have survived computer glitches and blistering weather conditions. “These rovers are incredibly resilient,” said a NASA project manager.
The rovers’ yearly operating cost of $20 million is “an extraordinary return of investment in challenging budgetary times,” explained another official. The probes have traveled more than 13 miles, snapped 250,000 photographs, and beamed more than 36GB of data to Earth. And they're not done yet. “We keep setting the bar higher for what these rovers can do," said a scientist.