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Discovery is an ongoing program that offers the scientific community the opportunity to assemble a team and design exciting, focused investigations that complement NASA's larger planetary science explorations. The goal is to achieve outstanding results launching many smaller missions using fewer resources and shorter development times than past projects with comparable objectives. The main objective is to enhance our understanding of the Solar System by exploring the planets, their moons, and small bodies such as comets and asteroids.

The 2006 NASA Strategic Plan identifies the following goal for Planetary Science : "Advance scientific knowledge of the origin and history of the solar system, the potential for life elsewhere, and the hazards and resources present as humans explore space." NASA's Science Mission Directorate (SMD) has responsibility for defining, planning and overseeing NASA's space and Earth science programs.

The Solar System Exploration Roadmap, published by NASA in September 2006, is drawn as a 30-year planning horizon, against the backdrop of the Presidential Initiative, "The Vision for Space Exploration." It excludes the Moon and Mars, which are covered in other Roadmaps. The scientific foundation of the Roadmap is a set of fundamental questions based on five objectives adopted in 2003 by NASA's then Office of Space Science, in response to the National Research Council's Decadal Survey, but modified to reflect the context of the exploration goals of the Vision for Space Exploration:

1. How did the Sun's family of planets and minor bodies originate?
2. How did the Solar System evolve to its current diverse state?
3. What are the characteristics of the Solar System that led to the origin of life?
4. How did life begin and evolve on Earth and has it evolved elsewhere in the Solar System?
5. What are the hazards and resources in the Solar System environment that will affect the extension of human presence in space?

The Roadmap describes a balanced series of small (Discovery Program), medium (New Frontiers Program), and large (flagship) class missions and their enabling technologies, supported by a balanced program of research and analysis, and creative education and public outreach.

The Science Plan for NASA's Science Mission Directorate 2007-2016 further defines NASA's vision for the scientific exploration of our planet, other planets and planetary bodies, our star system in its entirety, and the universe beyond.

All these documents can be accessed on the SMD's Science Strategy web page, which contains Current Strategy Documents, Community Input documents, and Past Strategy Documents.

To accomplish its prime objective of enhancing our understanding of the Solar System, the unique approach of the Discovery Program is to:

  • increase flight rates
  • contain total mission costs
  • improve performance through the use of new technology
  • broaden university and industry participation, and
  • increase public awareness of solar system exploration.

Discovery was among the first NASA programs to require a plan for education and public outreach, as NASA recognized the importance of communicating the excitement and meaning of space exploration to the public. Innovative methods that support national education initiatives are being developed to reach students of all ages. The vast possibilities available through the Internet greatly strengthen this effort.

Discovery advocates the testing and use of new technologies and applications. Each mission works with industry to transfer technologies used in the mission, especially those that enhance science acquisition and reduce cost.

Missions listed below were competitively selected under the Discovery Program. A mission is assigned to a division once the mission launches.

*Sort missions by clicking the column headers.

DivisionNameLaunch DatePhase
Planets Chandrayaan-1 (M3)
The Moon Mineralogy Mapper (M3) is one of two instruments that NASA is contributing to India's first mission to the Moon, Chandrayaan-1, which is scheduled to be launched in 2008. This mission is part of SMD's Discovery Program. This mission ...
20081022 October 22, 2008 4Past
The Comet Nucleus Tour (CONTOUR) was a mission intended to greatly expand what is known of comet nuclei and to assess their diversity. This mission is part of SMD's Discovery program.
20020703 July 03, 2002 4Past
Planets Dawn
The Dawn mission intends to orbit Vesta and Ceres, two of the largest asteroids in the solar system. According to current theories, the very different properties of Vesta and Ceres are the result of the asteroids being formed and evolving ...
20070927 September 27, 2007 3Operating
Planets Deep Impact
The Deep Impact mission was selected as a Discovery mission in 1999. The spacecraft was launched aboard a Delta II rocket on January 12, 2005 and left Earth’s orbit toward Comet Tempel 1. The spacecraft consists of two main sections, ...
20050112 January 12, 2005 4Past
Planets Epoxi
Extrasolar Planet Observation and Deep Impact Extended Investigation EPOXI is a follow-on mission to Deep Impact. This mission is part of SMD's Discovery program.
20050112 January 12, 2005 4Past
Planets Genesis
The Genesis mission was designed to collect samples of the charged particles in the solar wind and return them to Earth laboratories for detailed analysis. This mission is part of SMD's Discovery program.
20010808 August 08, 2001 4Past
Planets GRAIL
The Gravity Recovery and Interior Laboratory (GRAIL) mission is a Discovery Program mission to study the lunar interior. This mission is part of SMD's Discovery Program.
20110910 September 10, 2011 4Past
Astrophysics Kepler/K2
The Kepler Mission, a NASA Discovery mission, is specifically designed to survey our region of the Milky Way Galaxy to detect and characterize hundreds of Earth-size and smaller planets in or nearby the habitable zone.
20090306 March 06, 2009 3Operating
Planets Lunar Prospector
Lunar Prospector was the third of NASA's Discovery missions. The project mapped the chemical composition of the lunar surface and the Moon's global magnetic and gravity fields at a level of detail greater than that achieved by previous missions. This ...
19980107 January 07, 1998 4Past
Planets Mars Express (ASPERA-3)
Mars Express is exploring the atmosphere and surface of Mars from polar orbit. The mission's main objective is to search for sub-surface water from orbit and deploy a lander onto the Martian surface.
20030602 June 02, 2003 3Operating
Planets Mars Pathfinder
Mars Pathfinder launched December 2, 1996 and arrived on the surface of Mars on July 4, 1997. The mission was an engineering demonstration of key technologies and concepts for use in future missions to Mars; it also delivered science instruments ...
19961204 December 04, 1996 4Past
MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) is a scientific investigation of the planet Mercury, the least explored terrestrial planet. This mission is part of SMD's Discovery program.
20040803 August 03, 2004 3Operating
Planets NEAR-Shoemaker
As the first spacecraft to orbit and land on an asteroid, the Near Earth Asteroid Rendezvous Shoemaker mission continues to answer fundamental questions about the nature and origin of near-Earth objects. This mission is part of SMD's Discovery Program.
19960217 February 17, 1996 4Past
Planets Stardust
Stardust is the first U.S. space mission dedicated solely to the exploration of a comet, and the first robotic mission designed to return extraterrestrial material from outside the orbit of the Moon. This mission is part of SMD's Discovery Program. ...
19990207 February 07, 1999 4Past
Planets Stardust-NExT
STARDUST-NExT - short for "New Exploration of Tempel-1" - is a follow-on mission for STARDUST, one of the great successes of NASA's Discovery program.