On September 11, 2001 — the infamous day when two jetliners were hijacked and crashed into the Twin Towers of the World Trade Center, killing 2,752 people — engineers designing and building the Mars Exploration Rovers were working at Honeybee Robotics, just six blocks away. Not long after the catastrophic terrorist attack, the engineering team decided to honor the 9/11 victims by incorporating some of the World Trade Center debris into the rovers, known as Spirit and Opportunity. Pieces of aluminum from the downed towers were refashioned into cable shields for the units’ rock abrasion tools.
Rover still exploring Mars:
NASA’s Mars Exploration Rover mission began in 2003 with the launch of rockets carrying Spirit and Opportunity, which landed separately on the red planet in January 2004.
The rovers, designed to explore the Martian surface and collect data about its geology, were expected to last for 90 Martian days, but both have exceeded that — Spirit operated until 2010, and Opportunity is still going strong.
On May 16, 2013, Opportunity set a record for otherworldly exploration, having traveled more than 22 miles (35 km), enough to surpass the distance logged by Apollo 17’s lunar rover.