NASA's Discovery Program (as compared to New Frontiers, Explorers, or Flagship Programs) is a series of lower-cost, highly-focused American scientific space missions that are exploring the Solar System. It was founded in 1992 to implement then-NASA Administrator Daniel S. Goldin's vision of "faster, better, cheaper" planetary missions. Discovery missions differ from traditional NASA missions where targets and objectives are pre-specified. Instead, these cost-capped missions are proposed and led by a scientist called the Principal Investigator (PI). Proposing teams may include people from industry, small businesses, government laboratories, and universities. Proposals are selected through a competitive peer review process. All of the completed Discovery missions are accomplishing ground-breaking science and adding significantly to the body of knowledge about the Solar System.

NASA also accepts proposals for competitively selected Discovery Program Missions of Opportunity. This provides opportunities to participate in non-NASA missions by providing funding for a science instrument or hardware components of a science instrument or to re-purpose an existing NASA spacecraft. These opportunities are currently offered through NASA's Stand Alone Mission of Opportunity program.

The Voyager program is a U.S program that launched two unmanned space missions, scientific probes Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment of the late 1970s.

Although officially designated to study just Jupiter and Saturn, the probes were able to continue their mission into the outer solar system, and are as of December 2011 on course to exit the solar system. These probes were built at JPL and were funded by NASA. Voyager 1 is currently the farthest human-made object from Earth.

Both missions have gathered large amounts of data about the gas giants of the solar system, of which little was previously known. In addition, the spacecraft trajectories have been used to place limits on the existence of a hypothetical trans-Plutonian Planet X.

The Solar and Heliospheric Observatory (SOHO) mission purpose is to study the Sun from a point of gravitational balance.

The SOHO spacecraft has been built by a European industrial consortium led by Matra Marconi Space (now Astrium) that was launched on a Lockheed MartinAtlas IIAS launch vehicle on December 2, 1995 to study the Sun, and has discovered over 2100 comets. It began normal operations in May 1996.

It is a joint project of international cooperation between the European Space Agency (ESA) and NASA. Originally planned as a two-year mission,SOHO currently continues to operate after over fifteen years in space. In October 2009, a mission extension lasting until December 2012 was approved.

In addition to its scientific mission, it is currently the main source of near-real time solar data for space weather prediction. Along with the GGS Wind and Advanced Composition Explorer (ACE),SOHO is one of three spacecraft currently in the vicinity of the Earth-Sun L1 point, a point of gravitational balance located approximately 0.99 astronomical unit (AU)s from the Sun and 0.01 AU from the Earth. In addition to its scientific contributions, SOHO is distinguished by being the first three-axis-stabilized spacecraft to use its reaction wheels as a kind of virtual gyroscope; the technique was adopted after an on-board emergency in 1998 that nearly resulted in the loss of the spacecraft.

The Kepler spacecraft is an American space observatory, the space-based portion of NASA's Kepler mission to discover Earth-like planets orbiting other stars. The spacecraft is named in honor of the 17th-century German astronomer Johannes Kepler. The spacecraft was launched on March 7, 2009, with a planned mission lifetime of at least 3.5 years.

The Kepler mission is "specifically designed to survey a portion of our region of theMilky Way galaxy to discover dozens of Earth-size planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets." Kepler's only instrument is a photometer that continuously monitors the brightness of over 145,000 main sequence stars in a fixed field of view. This data isanalyzed to detect periodic fluctuations that indicate the presence of extrasolar planets that are in the process of crossing the face of other stars.

The Russian Federal Space Agency (Russian: Федеральное космическое агентство России Federal'noye kosmicheskoye agentstvo Rossii), commonly called Roscosmos (Роскосмос Roskosmos) and abbreviated as FKA (ФКА) and RKA (РКА), is the government agency responsible for the Russian space science program and general aerospace research. It was previously the Russian Aviation and Space Agency (Russian: Российское авиационно-космическое агентство Rossiyskoe aviatsionno-kosmicheskoe agentsvo, commonly known as "Rosaviakosmos").

Headquarters of Roscosmos are located in Moscow.

Main Mission Control space flight operations center is located in a nearby city of Korolev. 

Cosmonauts Training Centre (GCTC) is in Star City.

Launch facilities used are Baikonur Cosmodrome in Kazakhstan(with most launches taking place there, both manned and unmanned) and Plesetsk Cosmodrome in northern Russia used primarily for unmanned flights of military designations.

ISRO is the Indian Space Research Organisation.

The objective of ISRO is to develop space technology and its application to various national tasks. Accordingly, Indian Space Research Organisation (ISRO) has successfully operationalised two major satellite systems namely Indian National Satellites (INSAT) for communication services and Indian Remote Sensing (IRS) satellites for management of natural resources; also, Polar Satellite Launch Vehicle (PSLV) for launching IRS type of satellites and Geostationary Satellite Launch Vehicle (GSLV) for launching INSAT type of satellites.

The Space Commission formulates the policies and oversees the implementation of the Indian space programme to promote the development and application of space science and technology for the socio-economic benefit of the country. DOS implements these programmes through, mainly Indian Space Research Organisation (ISRO), Physical Research Laboratory (PRL), National Atmospheric Research Laboratory (NARL), North Eastern-Space Applications Centre (NE-SAC) and Semi-Conductor Laboratory (SCL). The Antrix Corporation, established in 1992 as a government owned company, markets the space products and services.

JAXA is the Japan Aerospace Exploration Agency.

On October 1, 2003, the Institute of Space and Astronautical Science (ISAS), the National Aerospace Laboratory of Japan (NAL) and the National Space Development Agency of Japan (NASDA) were merged into one independent administrative institution to be able to perform all their activities in the aerospace field as one organization, from basic research and development to utilization. The resulting independent administrative institution is the Japan Aerospace Exploration Agency (JAXA.)

JAXA proposed its long-term vision, "JAXA2025," to realize its own mission. Under thecorporate message "Reaching for the skies, exploring space," JAXA is pursuing various aerospace fields and is striving to succeed with various research and development missions.

Arianespace was founded in 1980 as the world’s first satellite launch company. Today, it has 21 shareholders from 10 European countries. Since its creation, Arianespace has launched with Ariane launchers 298 payloads, accounting for more than half of the commercial satellites now in service worldwide.

In 2010, the company had revenues of 897 M€. As of 1st July 2011, Arianespace had 332 employees, including 258 at the company’s headquarters in Evry, near Paris, 63 at the Guiana Space Center in French Guiana, launch site for Ariane 5, Soyuz and Vega, and 11 at local offices in Washington DC (United States), Tokyo (Japan) and Singapore.

Arianespace offers launch service & solutions to satellite operators from around the world, including both private companies and government agencies, based on a complete family of launchers:

• Ariane 5 heavy-lift launch vehicle, operated at the Guiana Space Center (60 launches, including 46 successful launches in a row),  
• Soyuz medium launcher, which has been operated at Baikonur since 1999 (23 commercial launches, all successful), and which, after the success of the first launch on 21 October 2011, is now being operated at the Guiana Space Center,
• Vega light launcher, which will be operated at the Guiana Space Center starting 2012.

 The technical performance of its launch vehicles and a substantial order book have made Arianespace the world leader in satellite launch services for the last few years (as of 2012), with a market share exceeding 50%.