Uncrewed spacecraft in the context of Exploration of Mars

Interplanetary spaceflight or interplanetary travel is spaceflight (crewed or uncrewed) between bodies within a single planetary system. Spaceflights become interplanetary by accelerating spacecrafts beyond orbital speed, reaching escape velocity relative to Earth at 11.2 km/s, entering heliocentric orbit, possibly accelerating further, often by performing gravity assist flybys at Earth and other planets. Most of today's spaceflight remains Earth bound, with much less being interplanetary, all of which performed by uncrewed spacecrafts, and only just a few spaceflights having accelerated beyond, to system escape velocity, eventually performing interstellar spaceflight.

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.

Since 1958, NASA has overseen more than 1,000 uncrewed missions into Earth orbit or beyond. It has both launched its own missions and provided funding for private-sector missions. A number of NASA missions, including the Explorers Program, Voyager program, and New Frontiers program, are ongoing.

Human presence in space (also anthropogenic presence in space or humanity in space) is the direct and mediated presence or telepresence of humans in outer space, and in an extended sense across space including astronomical bodies. Human presence in space, particularly through mediation, can take many physical forms from space debris, uncrewed spacecraft, artificial satellites, space observatories, crewed spacecraft, art in space, to human outposts in outer space such as space stations.

While human presence in space, particularly its continuation and permanence can be a goal in itself, human presence can have a range of purposes and modes from space exploration, commercial use of space to extraterrestrial settlement or even space colonization and militarisation of space. Human presence in space is realized and sustained through the advancement and application of space sciences, particularly astronautics in the form of spaceflight and space infrastructure.

A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun itself are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits, as they orbit their respective planet (although the Moon has a convex orbit around the Sun).

The barycenter of the Solar System, while always very near the Sun, moves through space as time passes, depending on where other large bodies in the Solar System, such as Jupiter and other large gas giants, are located at that time. A similar phenomenon allows the detection of exoplanets by way of the radial-velocity method.

Northrop Grumman Corporation, headquartered in West Falls Church, Virginia, is an American aerospace and defense company that designs and manufactures systems for aeronautics, defense, missions, and space. The company is the 5th largest contractor of the U.S. federal government; it receives over 2% of total spending by the federal government of the United States on contractors.

The company's Aeronautics Systems division (29% of 2024 revenues) develops the B-21 Raider strategic bomber that can drop conventional and thermonuclear weapons (forecasted to be ready for combat in 2029), the B-2 Spirit strategic bomber (which will be replaced by the B-21), fuselage and radar production for the Lockheed Martin F-35 Lightning II Joint Strike Fighter and F/A-18 Super Hornet, Grumman E-2 Hawkeye airborne early warning and control, MQ-4C Triton unmanned aerial vehicle, and the NATO Alliance Ground Surveillance Force. The company's defense systems division (19% of 2024 revenues) designs the modernization of the intercontinental ballistic missile system including the LGM-35 Sentinel, the Integrated Air and Missile Defense Battle Command System, Vinnell training, and the M1156 precision guidance kit. The company's mission systems division (25% of 2024 revenues) creates military radar, sensors, and related products, including C4I radar systems for air defense, Airspace Management radar systems such as AWACS, Multi-Platform Radar Technology Insertion Program, night vision goggles, Airport Movement Area Safety System, and battlefield surveillance systems like the Airborne Reconnaissance Low (ARL). Tactical aircraft sensors include the AN/APG-68 radar, the AN/APG-80 Active electronically scanned array radar, and the AN/APG-83 AESA radar upgrade for the F-16 Fighting Falcon, the AN/APG-77 AESA radar for the F-22 Raptor, and the AN/APG-81 AESA radar for the F-35 Lightning II, and the AN/AAQ-37 electro-optical Distributed Aperture System (DAS) for the F-35, and the APQ-164 Passive Electronically Scanned Array (PESA) radar for the B-1 Lancer. The company's space systems division (27% of 2024 revenues) develops Satcom communications satellites, Next-Generation Overhead Persistent Infrared satellites, the Cygnus uncrewed spacecraft, motors for the NASA Space Launch System, logistics support for the Lunar Gateway, Graphite-Epoxy Motor solid rocket boosters, and satellites for the Norwegian Space Agency.

Starship is a two-stage, fully reusable, super heavy-lift launch vehicle under development by American aerospace company SpaceX. Currently built and launched from Starbase in Texas, it is intended as the successor to the company's Falcon 9 and Falcon Heavy rockets, and is part of SpaceX's broader reusable launch system development program. If completed as designed, Starship would be the first fully reusable orbital rocket and have the highest payload capacity of any launch vehicle to date. As of October 13, 2025, Starship has launched 11 times, with 6 successful flights and 5 failures.

The vehicle consists of two stages: the Super Heavy booster and the Starship spacecraft, both powered by Raptor engines burning liquid methane (the main component of natural gas) and liquid oxygen. Both stages are intended to return to the launch site and land vertically at the launch tower for potential reuse. Once in space, the Starship upper stage is intended to function as a standalone spacecraft capable of carrying crew and cargo. Missions beyond low Earth orbit would require multiple in-orbit refueling flights. At the end of its mission, Starship reenters the atmosphere using heat shield tiles similar to those of the Space Shuttle. SpaceX states that its goal is to reduce launch costs by both reusing and mass producing both stages.

Luna 18, part of the Ye-8-5 series, was an uncrewed space mission of the Luna program.

Cygnus is an expendable American uncrewed cargo spacecraft developed for International Space Station (ISS) resupply missions. It was originally built by Orbital Sciences Corporation with financial support from NASA under the Commercial Orbital Transportation Services (COTS) program. The spacecraft consists of a pressurized cargo module—based largely on the Multi-Purpose Logistics Module and built by Thales Alenia Space—paired with a service module derived from Orbital's GEOStar, a satellite bus. Following a successful demonstration flight in 2013, Orbital was awarded a Commercial Resupply Services (CRS) contract.

Over time, Cygnus has been upgraded to increase its size and capabilities. The Enhanced Cygnus variant debuted in 2015, and the further enlarged Cygnus XL entered service in 2025. Features added over time include reboost capability to raise the ISS orbit, the ability to support late cargo loading shortly before launch, and the option to conduct secondary missions after undocking. Each mission ends with a controlled destructive reentry, which also provides a means of disposing of waste generated aboard the station. Alongside Cygnus, other ISS resupply spacecraft have included the Russian Progress, the European Automated Transfer Vehicle, the Japanese H-II Transfer Vehicle, and the American SpaceX Dragon.

Ulysses (/juːˈlɪsiːz/ yoo-LISS-eez, UK also /ˈjuːlɪsiːz/ YOO-liss-eez) was a robotic space probe whose primary mission was to orbit the Sun and study it at all latitudes. It was launched in 1990 and made three "fast latitude scans" of the Sun in 1994/1995, 2000/2001, and 2007/2008. In addition, the probe studied several comets. Ulysses was a joint venture of the European Space Agency (ESA) and the United States' National Aeronautics and Space Administration (NASA), under leadership of ESA with participation from Canada's National Research Council. The last day for mission operations on Ulysses was 30 June 2009.

To study the Sun at all latitudes, the probe needed to change its orbital inclination and leave the plane of the Solar System. To change the orbital inclination of a spacecraft to about 80° requires a large change in heliocentric velocity, the energy to achieve which far exceeded the capabilities of any launch vehicle. To reach the desired orbit around the Sun, the mission's planners chose a gravity assist maneuver around Jupiter, but this Jupiter encounter meant that Ulysses could not be powered by solar cells. The probe was powered instead by a General-Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG).

AS-201 (Also known as SA-201, Apollo 1-A, or Apollo 1 prior to the 1967 pad fire, flown February 26, 1966, was the first uncrewed test flight of an entire production Block I Apollo command and service module and the Saturn IB launch vehicle. The spacecraft consisted of the second Block I command module and the first Block I service module. The suborbital flight was a partially successful demonstration of the service propulsion system and the reaction control systems of both modules, and successfully demonstrated the capability of the command module's heat shield to survive re-entry from low Earth orbit.