Mission and Science Objectives

Could comets have brought water to Earth?
Comets preserve important clues to the early history of the solar system. They are believed to have contributed some of the volatiles that make up our oceans and atmosphere. They may even have brought to Earth the complex molecules from which life arose.

For these reasons, the Committee on Planetary and Lunar Exploration (COMPLEX) has emphasized the direct exploration of comets by spacecraft. The investigation of comets also addresses each of the three strategic objectives for solar system exploration enunciated in NASA’s Space Science Enterprise Strategy (SSES) 2003.

- To learn how the solar system originated and evolved to its current state.
- To understand how life begins and determine the characteristics of the solar system that led to the origin of life.
- To catalog and understand the potential impact hazard to Earth from space.

The Stardust-NExT mission contributed significantly to the first and last of these objectives by obtaining essential new data on Tempel 1 and capitalized on the discoveries of earlier missions such as Deep Impact to determine how cometary nuclei were constructed at the birth of the solar system and increased our understanding of how they have evolved since then.

The Stardust-NExT mission provided NASA with the unique opportunity to study two entirely different comets with the same instrument. By doing this, scientists were able to more accurately compare its existing data set.

The primary science objectives of the mission were as follows:

• To extend our understanding of the processes that affect the surfaces of comet nuclei by documenting the changes that have occurred on comet Tempel 1 between two successive perihelion passages.
• To extend the geologic mapping of the nucleus of Tempel 1 to elucidate the extent and nature of layering and help models of the formation and structure of comet nuclei.
• To extend the study of smooth flow deposits, active areas, and known exposure of water ice.
• Document the surface changes on a comet’s nucleus between successive perihelion passages.
• Measure Tempel 1’s dust properties and compare with data taken from Comet Wild 2.
• Provide additional information on enigmatic layering and flow features discovered by the Deep Impact mission
• On-board instruments will image the nucleus surface and jets; count dust particles size and distribution during closest approach; and composition of dust for further ground analysis.

Other Objectives:

• If possible, to characterize the crater produced by Deep Impact in July 2005 to better understand the structure and mechanical properties of cometary nuclei and elucidate crater formation processes on them.
• Measure the flux and mass distribution of dust particles within the coma using the DFMI instrument.
• Analyze the composition of dust particles within the coma using the CIDA instrument.
• Monitor comet activity over 60 days on approach using imaging.