Interstellar travel is the hypothetical travel of spacecraft between star systems. Due to the vast distances between the Solar System and nearby stars, interstellar travel is not practicable with current propulsion technologies.
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.
Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is currently carried out mainly by astronomers with telescopes, its physical exploration is conducted both by uncrewed robotic space probes and human spaceflight. Space exploration, like its classical form astronomy, is one of the main sources for space science.
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.
Voyager 1 is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and the interstellar space beyond the Sun's heliosphere. It was launched 16 days after its twin, Voyager 2. It communicates through the NASA Deep Space Network (DSN) to receive routine commands and to transmit data to Earth. Real-time distance and velocity data are provided by NASA and JPL. At a distance of 165.2 AU from Earth as of October 2024, it is the most distant human-made object from Earth. The probe made flybys of Jupiter, Saturn, and Saturn's largest moon, Titan. NASA had a choice of either doing a Pluto or Titan flyby; exploration of the moon took priority because it was known to have a substantial atmosphere. Voyager 1 studied the weather, magnetic fields, and rings of the two gas giants and was the first probe to provide detailed images of their moons.
Voyager 2 is a space probe launched by NASA on August 20, 1977, as a part of the Voyager program. It was launched on a trajectory towards the gas giants Jupiter and Saturn and enabled further encounters with the ice giants Uranus and Neptune. It remains the only spacecraft to have visited either of the ice giant planets, and was the third of five spacecraft to achieve Solar escape velocity, which will allow it to leave the Solar System. Launched 16 days before its twin Voyager 1, the primary mission of the spacecraft was to study the outer planets and its extended mission is to study interstellar space beyond the Sun's heliosphere.
A spacecraft is a vehicle that is designed to fly and operate in outer space. Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle.
Space technology is technology for use in outer space. Space technology includes space vehicles such as spacecraft, satellites, space stations and orbital launch vehicles; deep-space communication; in-space propulsion; and a wide variety of other technologies including support infrastructure equipment, and procedures.
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 starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" appears as early as 1882 in Oahspe: A New Bible.
Spaceflight is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth, but also includes space probes for flights beyond Earth orbit. Such spaceflights operate either by telerobotic or autonomous control. The first spaceflights began in the 1950s with the launches of the Soviet Sputnik satellites and American Explorer and Vanguard missions. Human spaceflight programs include the Soyuz, Shenzhou, the past Apollo Moon landing and the Space Shuttle programs. Other current spaceflight are conducted to the International Space Station and to China's Tiangong Space Station.
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.
The Journal of the British Interplanetary Society (JBIS) is a monthly peer-reviewed scientific journal that was established in 1934. The journal covers research on astronautics and space science and technology, including spacecraft design, nozzle theory, launch vehicle design, mission architecture, space stations, lunar exploration, spacecraft propulsion, robotic and crewed exploration of the solar system, interstellar travel, interstellar communications, extraterrestrial intelligence, philosophy, and cosmology. It is published monthly by the British Interplanetary Society.
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 following outline is provided as an overview of and topical guide to space exploration.
The 100 Year Starship project (100YSS) was a one-year joint U.S. Defense Advanced Research Projects Agency (DARPA) and National Aeronautics and Space Administration (NASA) effort "to take the first step in the next era of space exploration—a journey between the stars". The study explored development of a viable and sustainable model for persistent, long-term, private-sector investment into the myriad of disciplines needed to make interstellar space travel practicable and feasible. The goal was to examine what it would take — organizationally, technically, sociologically and ethically — to develop the ability to send humans to another star within 100 years. The study culminated in a $500,000 grant awarded to a consortium under the lead of the Dorothy Jemison Foundation for Excellence, which led to the creation of an independent organization inheriting the name 100 Year Starship from DARPA. Annual 100YSS symposia were organized from 2011 to 2015, and again in 2023.
DESTINY+ (Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science) is a planned mission to flyby the Geminids meteor shower parent body 3200 Phaethon, and sample dust originating from the "rock comet". The spacecraft is being developed by the Japanese space agency JAXA and will demonstrate advanced technologies for future deep space exploration. As of October 2024, DESTINY+ is planned to be launched in fiscal year 2028.
The future of space exploration involves both telescopic and physical explorations of space by robotic spacecraft and human spaceflight. Near-term physical exploration missions, focused on obtaining new information about the Solar System, are planned and announced by both national and private organisations.
