Interplanetary spaceflight or interplanetary travel is the crewed or uncrewed travel between stars and planets, usually within a single planetary system. In practice, spaceflights of this type are confined to travel between the planets of the Solar System. Uncrewed space probes have flown to all the observed planets in the Solar System as well as to dwarf planets Pluto and Ceres, and several asteroids. Orbiters and landers return more information than fly-by missions. Crewed flights have landed on the Moon and have been planned, from time to time, for Mars, Venus and Mercury. While many scientists appreciate the knowledge value that uncrewed flights provide, the value of crewed missions is more controversial. Science fiction writers propose a number of benefits, including the mining of asteroids, access to solar power, and room for colonization in the event of an Earth catastrophe.
Mariner 2, an American space probe to Venus, was the first robotic space probe to conduct a successful planetary encounter. The first successful spacecraft in the NASA Mariner program, it was a simplified version of the Block I spacecraft of the Ranger program and an exact copy of Mariner 1. The missions of the Mariner 1 and 2 spacecraft are sometimes known as the Mariner R missions. Original plans called for the probes to be launched on the Atlas-Centaur, but serious developmental problems with that vehicle forced a switch to the much smaller Agena B second stage. As such, the design of the Mariner R vehicles was greatly simplified. Far less instrumentation was carried than on the Soviet Venera probes of this period—for example, forgoing a TV camera—as the Atlas-Agena B had only half as much lift capacity as the Soviet 8K78 booster. The Mariner 2 spacecraft was launched from Cape Canaveral on August 27, 1962, and passed as close as 34,773 kilometers (21,607 mi) to Venus on December 14, 1962.
Mariner 1, built to conduct the first American planetary flyby of Venus, was the first spacecraft of NASA's interplanetary Mariner program. Developed by Jet Propulsion Laboratory, and originally planned to be a purpose-built probe launched summer 1962, Mariner 1's design was changed when the Centaur proved unavailable at that early date. Mariner 1, were then adapted from the lighter Ranger lunar spacecraft. Mariner 1 carried a suite of experiments to determine the temperature of Venus as well to measure magnetic fields and charged particles near the planet and in interplanetary space.
STS-72 was a Space Shuttle Endeavour mission to capture and return to Earth a Japanese microgravity research spacecraft known as Space Flyer Unit (SFU). The mission launched from Kennedy Space Center, Florida on 11 January 1996.
The Japan Aerospace Exploration Agency (JAXA) is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orbit, and is involved in many more advanced missions such as asteroid exploration and possible human exploration of the Moon. Its motto is One JAXA and its corporate slogan is Explore to Realize.
H-IIA (H-2A) is an active expendable launch system operated by Mitsubishi Heavy Industries (MHI) for the Japan Aerospace Exploration Agency. These liquid fuel rockets have been used to launch satellites into geostationary orbit; lunar orbiting spacecraft; Akatsuki, which studied the planet Venus; and the Emirates Mars Mission, which was launched to Mars in July 2020. Launches occur at the Tanegashima Space Center. The H-IIA first flew in 2001. As of December 2021, H-IIA rockets were launched 45 times, including 39 consecutive missions without a failure, dating back to 29 November 2003.
Akatsuki, also known as the Venus Climate Orbiter (VCO) and Planet-C, is a Japan Aerospace Exploration Agency (JAXA) space probe tasked with studying the atmosphere of Venus. It was launched aboard an H-IIA 202 rocket on 20 May 2010, but failed to enter orbit around Venus on 6 December 2010. After the craft orbited the Sun for five years, engineers successfully placed it into an alternative Venusian elliptic orbit on 7 December 2015 by firing its attitude control thrusters for 20 minutes and made it the first Japanese satellite orbiting Venus.
H-IIB (H2B) was an expendable space launch system jointly developed by the Japanese government's space agency JAXA and Mitsubishi Heavy Industries. It was used to launch the H-II Transfer Vehicle cargo spacecraft for the International Space Station. The H-IIB was a liquid-fueled rocket, with solid-fuel strap-on boosters and was launched from the Tanegashima Space Center in southern Japan. H-IIB made its first flight in 2009, and had made a total of nine flights through 2020 with no failures.
Kounotori 2, also known as HTV-2, was launched in January 2011 and was the second flight of the Japanese H-II Transfer Vehicle to resupply the International Space Station (ISS). It was launched by the H-IIB Launch Vehicle No. 2 manufactured by Mitsubishi Heavy Industries (MHI) and JAXA. After the supplies were unloaded, Kounotori 2 was loaded with waste material from ISS, including used experiment equipment and used clothes. Kounotori 2 was then unberthed and separated from the ISS and burned up upon reentering the atmosphere on 30 March 2011.
IKAROS is a Japan Aerospace Exploration Agency (JAXA) experimental spacecraft. The spacecraft was launched on 20 May 2010, aboard an H-IIA rocket, together with the Akatsuki probe and four other small spacecraft. IKAROS is the first spacecraft to successfully demonstrate solar sail technology in interplanetary space.
Waseda-SAT2 is a Japanese satellite which launched in May 2010. It is a student-built spacecraft, which will be operated by Waseda University, and is intended to be used for Earth observation and technology demonstration. It will test the use of extendible paddles to provide attitude control. The satellite is a single unit CubeSat.
Hayato, known before launch as KSAT, or the Kagoshima Satellite, is a Japanese satellite which was launched on 20 May 2010. It is a student-built spacecraft, which is operated by Kagoshima University, and is being used for technology demonstration and atmospheric research. The satellite is a single unit CubeSat, and carries equipment to study water vapour in the Earth's atmosphere, microwave imagery and spacecraft communication.
Negai☆″ is a Japanese satellite which launched in May 2010. It is a student-built spacecraft, which will be operated by Soka University, and is intended to be used for technology demonstration. The satellite is a single unit CubeSat, and will be used to test a field programmable gate array in orbit. As part of an outreach programme, it will carry the names of selected children, along with wishes they have made. The satellite will return images of the Earth, which will be given to the participating children.
SERVIS-2, or Space Environment Reliability Verification Integrated System 2, is a Japanese technological research satellite which was launched in 2010. It was constructed by Mitsubishi Electric, and will be operated by the Institute for Unmanned Space Experiment Free Flyer, USEF. It follows on from the SERVIS-1 spacecraft, which was launched in 2003.
Mars 1M No.1, designated Mars 1960A by NASA analysts and dubbed Marsnik 1 by the Western media, was the first spacecraft launched as part of the Soviet Union's Mars programme. A Mars 1M spacecraft, it was intended for conducting flight testing system and to study the interplanetary environment between Earth and Mars, however it was lost in a launch failure before it could begin its mission.
Orbital-1, also known as Orb-1, was the second flight of the Orbital Sciences Cygnus cargo spacecraft, its second flight to the International Space Station (ISS) and the third launch of the company's Antares launch vehicle. The mission launched on 9 January 2014 at 18:07:05 UTC.
Space Tethered Autonomous Robotic Satellite II or STARS-II, was a nanosatellite built by Japan's Kagawa University to test an electrodynamic tether in low Earth orbit, a follow-on to the STARS mission.
Manfred Memorial Moon Mission (4M) was the first private lunar probe to successfully fly by the Moon. It was led by LuxSpace, a child company of German OHB System, and named in honor of OHB Systems founder, professor Manfred Fuchs, who died in 2014. It was launched with the Chinese Chang'e 5-T1 test spacecraft on 23 October 2014. The lunar flyby took place on 28 October 2014, after which the spacecraft entered elliptical Earth orbit and continued transmission until 11 November 2014, exceeding its designed lifetime by four times.
NG-13, previously known as OA-13, was the fourteenth flight of the Northrop Grumman robotic resupply spacecraft Cygnus and its thirteenth flight to the International Space Station (ISS) under the Commercial Resupply Services (CRS-1) contract with NASA. The mission launched on 15 February 2020 at 20:21:01 UTC after nearly a week of delays. This is the second launch of Cygnus under the CRS-2 contract.
Orbiting Vehicle 1-2, launched 5 October 1965, was the third, and first successful, satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. A radiation measuring satellite designed to conduct research for the planned Manned Orbital Laboratory project, OV1-2 was the first American spacecraft to be placed into orbit on a western trajectory. The satellite stopped functioning in April 1967 after a series of technical problems starting two months after launch.
