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.
The following outline is provided as an overview and topical guide to space science:
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 spaceflight operate either by telerobotic or autonomous control. The more complex human spaceflight has been pursued soon after the first orbital satellites and has reached the Moon and permanent human presence in space around Earth, particularly with the use of space stations. 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.
Astronautics is the practice of sending spacecraft beyond Earth's atmosphere into outer space. Spaceflight is one of its main applications and space science is its overarching field.
Space adaptation syndrome (SAS) or space sickness is a condition experienced by as many as half of all space travelers during their adaptation to weightlessness once in orbit. It is the opposite of terrestrial motion sickness since it occurs when the environment and the person appear visually to be in motion relative to one another even though there is no corresponding sensation of bodily movement originating from the vestibular system.
A life-support system is the combination of equipment that allows survival in an environment or situation that would not support that life in its absence. It is generally applied to systems supporting human life in situations where the outside environment is hostile, such as outer space or underwater, or medical situations where the health of the person is compromised to the extent that the risk of death would be high without the function of the equipment.
Artificial gravity is the creation of an inertial force that mimics the effects of a gravitational force, usually by rotation. Artificial gravity, or rotational gravity, is thus the appearance of a centrifugal force in a rotating frame of reference, as opposed to the force experienced in linear acceleration, which by the equivalence principle is indistinguishable from gravity. In a more general sense, "artificial gravity" may also refer to the effect of linear acceleration, e.g. by means of a rocket engine.
The effects of spaceflight on the human body are complex and largely harmful over both short and long term. Significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton. Other significant effects include a slowing of cardiovascular system functions, decreased production of red blood cells, balance disorders, eyesight disorders and changes in the immune system. Additional symptoms include fluid redistribution, loss of body mass, nasal congestion, sleep disturbance, and excess flatulence. A 2024 assessment noted that "well-known problems include bone loss, heightened cancer risk, vision impairment, weakened immune systems, and mental health issues... [y]et what’s going on at a molecular level hasn’t always been clear", arousing concerns especially vis a vis private and commercial spaceflight now occurring without any scientific or medical research being conducted among those populations regarding effects.
Space medicine is a component of the specialty of Aerospace Medicine, and has primarily focused on prevention of medical conditions that would limit success in space operations.
Aerospace Medicine has been a recognized specialty since 1955. Space medicine focuses specifically on preventive medical care of astronauts and spaceflight participants and performance optimization. The spaceflight environment poses many unique stressors to the human body, including G forces, microgravity, unusual atmospheres such as low pressure or high carbon dioxide, and space radiation. Space medicine applies space physiology, preventive medicine, primary care, emergency medicine, acute care medicine, austere medicine, public health, and toxicology to prevent and treat medical problems in space. This expertise is additionally used to inform vehicle systems design to minimize the risk to human health and performance while meeting mission objectives.
Gravitational biology is the study of the effects gravity has on living organisms. Throughout the history of the Earth life has evolved to survive changing conditions, such as changes in the climate and habitat. However, one constant factor in evolution since life first began on Earth is the force of gravity. As a consequence, all biological processes are accustomed to the ever-present force of gravity and even small variations in this force can have significant impact on the health and function and the system of organisms.
Astrobotany is an applied sub-discipline of botany that is the study of plants in space environments. It is a branch of astrobiology and botany.
Astronautical hygiene evaluates, and mitigates, hazards and health risks to those working in low-gravity environments. The discipline of astronautical hygiene includes such topics as the use and maintenance of life support systems, the risks of the extravehicular activity, the risks of exposure to chemicals or radiation, the characterization of hazards, human factor issues, and the development of risk management strategies. Astronautical hygiene works side by side with space medicine to ensure that astronauts are healthy and safe when working in space.
Weightlessness is the complete or near-complete absence of the sensation of weight, i.e., zero apparent weight. It is also termed zero g-force, or zero-g or, incorrectly, zero gravity.
ELIPS - European Programme for Life and Physical Sciences in Space and applications utilising the International Space Station started in 2001 and was intended to cover the activities for the following 5 years. This Microgravity Programme at the European Space Agency (ESA) is an optional programme, with currently 17 ESA member states participating. The ELIPS programme prepares and performs research on the International Space Station, and other uncrewed mission platforms like Sounding Rockets, in fundamental and applied life and physical sciences. ELIPS is the continuation of the earlier European microgravity programmes EMIR 1&2, and the Microgravity Facilities for Columbus, MFC.
Space neuroscience or astroneuroscience is the scientific study of the central nervous system (CNS) functions during spaceflight. Living systems can integrate the inputs from the senses to navigate in their environment and to coordinate posture, locomotion, and eye movements. Gravity has a fundamental role in controlling these functions. In weightlessness during spaceflight, integrating the sensory inputs and coordinating motor responses is harder to do because gravity is no longer sensed during free-fall. For example, the otolith organs of the vestibular system no longer signal head tilt relative to gravity when standing. However, they can still sense head translation during body motion. Ambiguities and changes in how the gravitational input is processed can lead to potential errors in perception, which affects spatial orientation and mental representation. Dysfunctions of the vestibular system are common during and immediately after spaceflight, such as space motion sickness in orbit and balance disorders after return to Earth.
It is inevitable that medical conditions of varying complexity, severity and emergency will occur during spaceflight missions with human participants. Different levels of care are required depending on the problem, available resources and time required to return to Earth.
The growth of plants in outer space has elicited much scientific interest. In the late 20th and early 21st century, plants were often taken into space in low Earth orbit to be grown in a weightless but pressurized controlled environment, sometimes called space gardens. In the context of human spaceflight, they can be consumed as food and provide a refreshing atmosphere. Plants can metabolize carbon dioxide in the air to produce valuable oxygen, and can help control cabin humidity. Growing plants in space may provide a psychological benefit to human spaceflight crews. Usually the plants were part of studies or technical development to further develop space gardens or conduct science experiments. To date plants taken into space have had mostly scientific interest, with only limited contributions to the functionality of the spacecraft, however the Apollo Moon tree project was more or less forestry inspired mission and the trees are part of a country's bicentennial celebration.
The following page is a list of scientific research that is currently underway or has been previously studied on the International Space Station by the European Space Agency.
Space psychology refers to applying psychology to advise human spaceflight. This includes applying industrial and organizational psychology to team selection, individual and team mental preparation, team training, and ongoing psychological support, and applying human factors and ergonomics to the construction of spacecraft to ensure sufficient habitability.
Crocco's Multiplanetary Trajectory, sometimes named Crocco's Mission and Crocco's "Grand Tour", is a mathematical description of an hypothetical Earth-Mars-Venus-Earth-Research Mission, which was first proposed in 1956 by the Aeronautics and Space Pioneer G. A. Crocco during the VII. International Astronautical Congress in Rome.
