ASPERA-3 is a mission of opportunity in which NASA equipment flies aboard an ESA spacecraft—the Mars Express orbiter. Mars Express launched in June 2003 and assumed orbit around the Red Planet five months later. As of February 2006 it is still orbiting Mars and collecting data. The full name of the instrument is the Analyzer of Space Plasma and Energetic Atoms. It was designed to assess the interaction between the solar wind and the Martian atmosphere. NASA funded two of the four sensors embedded in the instrument.

Deep Impact was launched on January 12, 2005, for an encounter with the comet Tempel-1. The comet was discovered by French astronomer Ernst Tempel in 1867. It orbits the sun between Mars and Jupiter with a 5.5-year orbital period. Deep Impact included an impactor probe that was released and penetrated the comet surface on July 4, 2005. The probe relayed data to the flyby portion of the spaceship. NASA scientists are using the data to determine the physical and chemical makeup of the comet. In September 2005 NASA announced that preliminary analyses showed the comet included expected components, such as silicates (sand), and unexpected components, including clay, carbonates, iron-bearing compounds, and aromatic hydrocarbons.

As of February 2006 the Deep Impact flyby spacecraft remains in a flight trajectory among the inner planets (Mercury, Venus, Earth, and Mars). It is scheduled to make a flyby of Earth in late 2007. NASA expects that the spacecraft will be used for a future Discovery Program mission of opportunity.