Skip to Main Content

How did the sun's family of planets and minor bodies originate?

For the first time in human history we know of planets around other stars and many of those other planetary systems look quite different from our own. Many have a planet like Jupiter, or even bigger, nearest to the Sun.  If we are to understand why this is the case, and how likely it is that there are Earth-like planets elsewhere, we need to better understand how planets form.

We might not be here if it were not for our moon, which makes our rotation axis stable.  Our planet might not be as wet and rich as it is if it were not for comets and asteroids that leave dust in our neighborhood.  Thus, we must understand the moons and other small bodies too, though modest by comparison these objects had a hand in our fate.

Studies of ancient meteorites, cosmic dust, and comets provide clues to the processes operating in the early solar system, and actually allow dating of events over 4.5 billion years ago.  Studying these objects, which have changed little since the first few million years of the Solar System’s existence, allows us to understand the components that made up the dust and gas cloud from which the Solar System formed, and the processes that led to the formation of  planets.  These analytical studies, in turn, inform theoretical studies of Solar System formation.

Related missions:

*Sort missions by clicking the column headers.

DivisionNameLaunch DatePhase
Planets Cassini
The Cassini Mission is in the midst of a detailed study of Saturn, its rings, its magnetosphere, its icy satellites, and its moon Titan. Cassini also delivered a probe (called Huygens, provided by the European Space Agency) to Titan, and ...
19971015 October 15, 1997 3Operating
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
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 3Operating
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 3Operating
Planets Hayabusa
The objective of Hayabusa (formerly Muses-C) mission was to collect a surface sample of material from the small asteroid and return the sample to Earth for analysis.
20030509 May 09, 2003 4Past
Planets ILN
International Lunar Net-work (ILN), was conceived in 2008 as a partnership among space-faring nations to establish a set of robotic geophysical monitoring stations on the surface of the Moon.
20180301 March 01, 2018 1Under Study
Planets LADEE
Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA mission that will orbit the Moon and its main objective is to characterize the atmosphere and lunar dust environment. This mission is part of SMD's Robotic Lunar Exploration program.
20130906 September 2013 2Development
Planets Lunar Reconnaisance Orbiter
The Lunar Reconnaissance Orbiter (LRO) is the first mission in NASA's plan to return to the moon and then to travel to Mars and beyond. This mission is part of SMD's Robotic Lunar Exploration program.
20090617 June 17, 2009 3Operating
Planets Mars Exploration Rover - Opportunity
The Mars Exploration Rover Opportunity was originally designed for a 90 Sol mission (a Sol, one Martian day, is slightly longer than an Earth day at 24 hours and 37 minutes). Its mission has been extended several times as it ...
20030707 July 07, 2003 3Operating
Planets Mars Exploration Rover - Spirit
Mars Exploration Rover Spirit landed in Gusev crater on Mars in January 2004. The rover carries a sophisticated set of instruments that allow it to search for evidence of liquid water that may have been present in the planet's past. ...
20030610 June 10, 2003 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 Global Surveyor
Mars Global Surveyor is returning an unprecedented amount of data regarding Mars' surface features, atmosphere, and magnetic properties. Scientists are using the data gathered from this mission both to learn about the Earth by comparing it to Mars, and to ...
19961107 November 07, 1996 4Past
Planets Mars Odyssey
The 2001 Mars Odyssey is an orbiter carrying science experiments designed to make global observations of Mars to improve our understanding of the planet's climate and geologic history, including the search for water and evidence of life-sustaining environments.
20010407 April 07, 2001 3Operating
Planets Mars Reconnaissance Orbiter
The Mars Reconnaissance Orbiter (MRO) will seek to find out about the history of water on Mars with its science instruments. They will zoom in for extreme close-up photography of the martian surface to analyze minerals, look for subsurface water, ...
20050812 August 12, 2005 3Operating
Planets MAVEN
The Mars Atmosphere and Volatile Evolution Mission (MAVEN), set to launch in 2013, will explore the planet’s upper atmosphere, ionosphere and interactions with the sun and solar wind. Scientists will use MAVEN data to determine the role that loss of ...
20131118 November 18, 2013 3Operating
Planets MESSENGER
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 New Horizons
The New Horizons Pluto-Kuiper Belt Mission will help us understand worlds at the edge of our solar system, by making the first reconnaissance of Pluto and Charon. The mission will then visit one or more Kuiper Belt Objects, in the ...
20060119 January 19, 2006 3Operating
Planets Phoenix
Phoenix seeks to verify the presence of the Martian Holy Grail: water and habitable conditions.
20070804 August 04, 2007 4Past
Planets Rosetta
The Rosetta Orbiter will study the origin of comets, the relationship between cometary and interstellar material and its implications with regard to the origin of the Solar System. This mission is part of SMD's Solar System Exploration Program.
20040302 March 02, 2004 3Operating
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.
4Past