There is also a more tangible piece of New York on Mars. On each rover, a curved piece of metal the size of a credit card and adorned with the American flag was cut out of debris from the World Trade Center.
The Honeybee engineers obtained a box of twisted metal from the city. Mr. Bartlett recalled the smell - "that acrid electrical fire smell" - when they opened it.
Tom Myrick, Honeybee's chief engineer, flew down to Texas with a piece of aluminum from the box. At the machine shop they employ there, the metal was turned into shields to protect cables on the drilling mechanisms.
Until now, that knowledge has remained within the mission team.
"It was intended to be a quiet tribute," Mr. Gorevan said. "Enough time has passed. We want the families to know."