Mars Surveyor '98

Mars Surveyor '98 was a mission in NASA's Mars Exploration Program that launched the Mars Climate Orbiter and the Mars Polar Lander to the planet Mars. The mission was to study the Martian weather, climate, water and carbon dioxide (CO₂) budget, to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes. The Mars Polar Lander also carried two surface-penetrator probes for the New Millennium Program's Deep Space 2 mission. Both spacecraft were launched in 1998 and both were lost.