Pioneer 11 is a NASA robotic space probe launched on April 5,1973,to study the asteroid belt,the environment around Jupiter and Saturn,the solar wind,and cosmic rays. It was the first probe to encounter Saturn,the second to fly through the asteroid belt,and the second to fly by Jupiter. Later,Pioneer 11 became the second of five artificial objects to achieve an escape velocity allowing it to leave the Solar System. Due to power constraints and the vast distance to the probe,the last routine contact with the spacecraft was on September 30,1995,and the last good engineering data was received on November 24,1995.
The Voyager program is an American scientific program that employs two interstellar probes,Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable alignment of the two gas giants Jupiter and Saturn and the ice giants,Uranus and Neptune,to fly near them while collecting data for transmission back to Earth. After launch,the decision was made to send Voyager 2 near Uranus and Neptune to collect data for transmission back to Earth.
A gravity assist,gravity assist maneuver,swing-by,or generally a gravitational slingshot in orbital mechanics,is a type of spaceflight flyby which makes use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft,typically to save propellant and reduce expense.
New Horizons is an interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institute (SwRI),with a team led by Alan Stern,the spacecraft was launched in 2006 with the primary mission to perform a flyby study of the Pluto system in 2015,and a secondary mission to fly by and study one or more other Kuiper belt objects (KBOs) in the decade to follow,which became a mission to 486958 Arrokoth. It is the fifth space probe to achieve the escape velocity needed to leave the Solar System.
Mariner Mark II was NASA's planned family of uncrewed spacecraft for the exploration of the outer Solar System that were to be developed and operated by JPL between 1980 through the year 2010.
The Grand Tour is a NASA program that would have sent two groups of robotic probes to all the planets of the outer Solar System. It called for four spacecraft,two of which would visit Jupiter,Saturn,and Pluto,while the other two would visit Jupiter,Uranus,and Neptune. The enormous cost of the project,around $1 billion,led to its cancellation and replacement with Mariner Jupiter-Saturn,which became the Voyager program.
An interstellar probe is a space probe that has left—or is expected to leave—the Solar System and enter interstellar space,which is typically defined as the region beyond the heliopause. It also refers to probes capable of reaching other star systems.
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of furthering the understanding of the Solar System. The program selects medium-class missions which can provide high science returns.
The exploration of Saturn has been solely performed by crewless probes. Three missions were flybys,which formed an extended foundation of knowledge about the system. The Cassini–Huygens spacecraft,launched in 1997,was in orbit from 2004 to 2017.
Neptune has been directly explored by one space probe,Voyager 2,in 1989. As of 2024,there are no confirmed future missions to visit the Neptunian system,although a tentative Chinese mission has been planned for launch in 2024. NASA,ESA,and independent academic groups have proposed future scientific missions to visit Neptune. Some mission plans are still active,while others have been abandoned or put on hold.
A planetary flyby is the act of sending a space probe past a planet or a dwarf planet close enough to record scientific data. This is a subset of the overall concept of a flyby in spaceflight.
The exploration of Pluto began with the arrival of the New Horizons probe in July 2015,though proposals for such a mission had been studied for many decades. There are no plans as yet for a follow-up mission,though follow-up concepts have been studied.
Argo was a 2009 spacecraft mission concept by NASA to the outer planets and beyond. The concept included flybys of Jupiter,Saturn,Neptune,and a Kuiper belt object. A focus on Neptune and its largest moon Triton would have helped answer some of the questions generated by Voyager 2's flyby in 1989,and would have provided clues to ice giant formation and evolution.
A flyby is a spaceflight operation in which a spacecraft passes in proximity to another body,usually a target of its space exploration mission and/or a source of a gravity assist to impel it towards another target. Spacecraft which are specifically designed for this purpose are known as flyby spacecraft,although the term has also been used in regard to asteroid flybys of Earth for example. Important parameters are the time and distance of closest approach.
The Planetary Missions Program Office is a division of NASA headquartered at the Marshall Space Flight Center,formed by the agency's Science Mission Directorate (SMD). Succeeding the Discovery and New Frontiers Program Office,it was established in 2014 to manage the Discovery and New Frontiers programs of low and medium-cost missions by third-party institutions,and the Solar System Exploration program of NASA-led missions that focus on prioritized planetary science objectives. The Discovery and New Frontiers programs were established in 1992 and 2001 respectively,and have launched fourteen primary missions together,along with two missions launched under the administration of the Planetary Missions Program Office. The Solar System Exploration Program was established alongside the office,with three missions planned for launch under the new program.
REX or Radio Science Experiment is an experiment on the New Horizons space probe to measure properties of the atmosphere of Pluto during the 2015 flyby.
Shensuo,formerly Interstellar Express,is a proposed Chinese National Space Administration program designed to explore the heliosphere and interstellar space. The program will feature two or three space probes that will purportedly be launched in 2024 and follow differing trajectories to encounter Jupiter to assist them out of the Solar System. The first probe,IHP-1,will travel toward the nose of the heliosphere,while the second probe,IHP-2,will fly near to the tail,skimming by Neptune and Triton in January 2038. There may be another probe—tentatively IHP-3—which would launch in 2030 to explore to the northern half of the heliosphere. IHP-1 and IHP-2 would be the sixth and seventh spacecraft to leave the Solar System,as well as first non-NASA probes to achieve this status.
Timeline for the New Horizons interplanetary space probe lists the significant events of the launch,transition phases as well as subsequent significant operational mission events;by date and brief description.
