TOP technologies for 2004

Aerospace Engineering's annual review of the technologies chosen by its readers to be the most significant.

In early January 2004, the first of two NASA Mars Exploration Rovers (MERs) called Spirit successfully landed on Mars, beginning an investigatory mission of great significance. It began its mission by sending the first color pictures of the planet's surface. The images were of the highest resolution ever sent from Mars-more than three times as detailed as images from Mars Pathfinder in 1997.

Spirit was the first of two golf-cart-sized rovers (the other is Opportunity) headed for Mars landings in January, and presaged many interesting future missions to the red planet. Since being launched in June and July 2003, each had been flying tucked inside a folded-up lander. Wrapped in deflated airbags, each lander was cocooned within a protective aeroshell and attached to a cruise stage that provided solar panels, antennas, and steering for its seven-month journey.