Interplanetary spaceflight - Knowledge (XXG)

524: 997: 918:). Because of these facts, a spacecraft desiring to transfer to a planet closer to the Sun must decrease its speed with respect to the Sun by a large amount in order to intercept it, while a spacecraft traveling to a planet farther out from the Sun must increase its speed substantially. Then, if additionally the spacecraft wishes to enter into orbit around the destination planet (instead of just flying by it), it must match the planet's orbital speed around the Sun, usually requiring another large velocity change. 1997: 72: 511:

consideration the velocity changes necessary to travel from one body to another in the Solar System. For orbital flights, an additional adjustment must be made to match the orbital speed of the destination body. Other developments are designed to improve rocket launching and propulsion, as well as the use of non-traditional sources of energy. Using extraterrestrial resources for energy, oxygen, and water would reduce costs and improve life support systems.

1608: 1239: 974:. However, the Hohmann transfer takes an amount of time similar to ½ of the orbital period of the outer orbit, so in the case of the outer planets this is many years – too long to wait. It is also based on the assumption that the points at both ends are massless, as in the case when transferring between two orbits around Earth for instance. With a planet at the destination end of the transfer, calculations become considerably more difficult. 989: 938: 1282:

rockets would be most useful at or near the Earth's surface and the consequences of a malfunction could be disastrous. Fission-based thermal rocket concepts produce lower exhaust velocities than the electric and plasma concepts described below, and are therefore less attractive solutions. For applications requiring high thrust-to-weight ratio, such as planetary escape, nuclear thermal is potentially more attractive.

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scientific knowledge per dollar spent; robots do not need costly life-support systems, can be sent on one-way missions, and are becoming more capable as artificial intelligence advances. Others argue that either astronauts or spacefaring scientists, advised by Earth-based scientists, can respond more flexibly and intelligently to new or unexpected features of whatever region they are exploring.

400: 1475: 780: 1103: 929:), in this case an increase, of about 3.8 km/s. Then, after intercepting Mars, it must change its speed by another 2.3 km/s in order to match Mars' orbital speed around the Sun and enter an orbit around it. For comparison, launching a spacecraft into low Earth orbit requires a change in speed of about 9.5 km/s. 507:. 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. 2097:) to be consumed by the crew members. Preliminary investigations have shown that deuterium-depleted water features certain anti-cancer effects. Hence, deuterium-free drinking water is considered to have the potential of lowering the risk of cancer caused by extreme radiation exposure of the Martian crew. 28: 3204:

So it is a bit tricky. Because we have to figure out how to improve the cost of the trips to Mars by five million percent ... translates to an improvement of approximately 4 1/2 orders of magnitude. These are the key elements that are needed in order to achieve a 4 1/2 order of magnitude improvement.

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A space elevator is a theoretical structure that would transport material from a planet's surface into orbit. The idea is that, once the expensive job of building the elevator is complete, an indefinite number of loads can be transported into orbit at minimal cost. Even the simplest designs avoid the

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would synchronously cycle between Mars and Earth, with very little propellant usage to maintain the trajectory. Cyclers are conceptually a good idea, because massive radiation shields, life support and other equipment only need to be put onto the cycler trajectory once. A cycler could combine several

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of planets and moons to change the speed and direction of a spacecraft without using fuel. In typical example, a spacecraft is sent to a distant planet on a path that is much faster than what the Hohmann transfer would call for. This would typically mean that it would arrive at the planet's orbit and

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launch vehicle, but the tests revealed reliability problems, mainly caused by the vibration and heating involved in running the engines at such high thrust levels. Political and environmental considerations make it unlikely such an engine will be used in the foreseeable future, since nuclear thermal

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This maneuver can only change an object's velocity relative to a third, uninvolved object, – possibly the “centre of mass” or the Sun. There is no change in the velocities of the two objects involved in the maneuver relative to each other. The Sun cannot be used in a gravitational slingshot because

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Due to the Sun's gravitational pull, a spacecraft moving farther from the Sun will slow down, while a spacecraft moving closer will speed up. Also, since any two planets are at different distances from the Sun, the planet from which the spacecraft starts is moving around the Sun at a different speed

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Some members of the general public mainly value space activities for whatever tangible benefits they may deliver to themselves or to the human race as a whole. So far the only benefits of this type have been "spin-off" technologies which were developed for space missions and then were found to be at

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to prevent the craft from burning up. As a result, aerobraking is only helpful in cases where the fuel needed to transport the heatshield to the planet is less than the fuel that would be required to brake an unshielded craft by firing its engines. This can be addressed by creating heatshields from

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where the returning spacecraft did not enter Earth orbit but instead used a S-shaped vertical descent profile (starting with an initially steep descent, followed by a leveling out, followed by a slight climb, followed by a return to a positive rate of descent continuing to splash-down in the ocean)

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of the transfer orbit is on the far side of the Sun near the orbit of the other planet. A spacecraft traveling from Earth to Mars via this method will arrive near Mars orbit in approximately 8.5 months, but because the orbital velocity is greater when closer to the center of mass (i.e. the Sun) and

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The most important non-terrestrial resource is energy, because it can be used to transform non-terrestrial materials into useful forms (some of which may also produce energy). At least two fundamental non-terrestrial energy sources have been proposed: solar-powered energy generation (unhampered by

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to be directly transferred to the interplanetary spacecraft. For returning mass to Earth, a related option is to mine raw materials from a solar system celestial object, refine, process, and store the reaction products (propellant) on the Solar System body until such time as a vehicle needs to be

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intended to lift payloads to high altitudes and speeds. Proposals for skyhooks include designs that employ tethers spinning at hypersonic speed for catching high speed payloads or high altitude aircraft and placing them in orbit. In addition, it has been suggested that the rotating skyhook is "not

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One of the main benefits of nuclear thermal propulsion is its efficiency. A nuclear thermal rocket can achieve more than twice the efficiency compared to a conventional chemical rocket because it's propellant is brought to a far higher temperature than can be achieved in a conventional combustion

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on May 21, 2010. It has since been successfully deployed, and shown to be producing acceleration as expected. Many ordinary spacecraft and satellites also use solar collectors, temperature-control panels and Sun shades as light sails, to make minor corrections to their attitude and orbit without

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Simply doing this by brute force – accelerating in the shortest route to the destination and then matching the planet's speed – would require an extremely large amount of fuel. And the fuel required for producing these velocity changes has to be launched along with the payload, and therefore even

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reactions, would "burn" such light element fuels as deuterium, tritium, or He. Because fusion yields about 1% of the mass of the nuclear fuel as released energy, it is energetically more favorable than fission, which releases only about 0.1% of the fuel's mass-energy. However, either fission or

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power, limiting their capability to operate far from the Sun, and also limiting their peak acceleration due to the mass of the electric power source. Nuclear-electric or plasma engines, operating for long periods at low thrust and powered by fission reactors, can reach speeds much greater than

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methane/oxygen propellants. It is 55 m (180 ft)-long, 9 m (30 ft)-diameter at its widest point, and is capable of transporting up to 100 tonnes (220,000 lb) of cargo and passengers per trip to Mars, with on-orbit propellant refill before the interplanetary part of the

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As of 2019, SpaceX is developing a system in which a reusable first stage vehicle would transport a crewed interplanetary spacecraft to Earth orbit, detach, return to its launch pad where a tanker spacecraft would be mounted atop it, then both fueled, then launched again to rendezvous with the

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publicizes spin-offs from its activities). However, public support, at least in the US, remains higher for basic scientific research than for human space flight; a 2023 survey found that Americans rate basic research as their third-highest priority for NASA, after monitoring Earth-endangering

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provides knowledge that could not be gained by observations from Earth's surface or from orbit around Earth. However, they disagree about whether human-crewed missions justify their cost and risk. Critics of human spaceflight argue that robotic probes are more cost-effective, producing more

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A number of techniques have been developed to make interplanetary flights more economical. Advances in computing and theoretical science have already improved some techniques, while new proposals may lead to improvements in speed, fuel economy, and safety. Travel techniques must take into

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to the starting and destination orbits. Once the spacecraft arrives, a second application of thrust will re-circularize the orbit at the new location. In the case of planetary transfers this means directing the spacecraft, originally in an orbit almost identical to Earth's, so that the

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In rocket engines. Even if the other propellant has to be lifted from Earth, using non-terrestrial oxygen could reduce propellant launch costs by up to 2/3 for hydrocarbon fuel, or 85% for hydrogen. The savings are so high because oxygen accounts for the majority of the mass in most

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slower when farther from the center, the spacecraft will be traveling quite slowly and a small application of thrust is all that is needed to put it into a circular orbit around Mars. If the manoeuver is timed properly, Mars will be "arriving" under the spacecraft when this happens.

1906:. A vessel traveling in the inner Solar System could maintain a constant heading relative to the Sun without overheating the side of the spacecraft facing the Sun, provided the water under the hull was constantly circulated to evenly distribute the solar heat throughout the hull; 1577:

of rocket launches from the surface, wherein the fuel needed to travel the last 10% of the distance into orbit must be lifted all the way from the surface, requiring even more fuel, and so on. More sophisticated space elevator designs reduce the energy cost per trip by using

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must be capable of supporting human life for weeks, months or even years. A breathable atmosphere of at least 35 kPa (5.1 psi) must be maintained, with adequate amounts of oxygen, nitrogen, and controlled levels of carbon dioxide, trace gases and water vapor.

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that they can keep firing continuously for days or weeks, while chemical rockets use up reaction mass so quickly that they can only fire for seconds or minutes. Even a trip to the Moon is long enough for an electric propulsion system to outrun a chemical rocket – the

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Any crewed interplanetary flight must include certain design requirements. Life support systems must be capable of supporting human lives for extended periods of time. Preventative measures are needed to reduce exposure to radiation and ensure optimum reliability.

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roles: habitat (for example it could spin to produce an "artificial gravity" effect); mothership (providing life support for the crews of smaller spacecraft which hitch a ride on it). Cyclers could also possibly make excellent cargo ships for resupply of a colony.

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continue past it. However, if there is a planet between the departure point and the target, it can be used to bend the path toward the target, and in many cases the overall travel time is greatly reduced. A prime example of this are the two crafts of the

1086:. Such "fuzzy orbits" use significantly less energy than Hohmann transfers but are much, much slower. They aren't practical for human crewed missions because they generally take years or decades, but may be useful for high-volume transport of low-value 3205:

Most of the improvement would come from full reusability—somewhere between 2 and 2 1/2 orders of magnitude—and then the other 2 orders of magnitude would come from refilling in orbit, propellant production on Mars, and choosing the right propellant.

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When launching interplanetary probes from the surface of Earth, carrying all energy needed for the long-duration mission, payload quantities are necessarily extremely limited, due to the basis mass limitations described theoretically by the

1518:: the sail splits into an outer and inner section, the outer section is pushed forward and its shape is changed mechanically to focus reflected radiation on the inner portion, and the radiation focused on the inner section acts as a brake. 1393:, and Mars orbital destinations. It incorporates a reduced-g centrifuge providing artificial gravity for crew health to ameliorate the effects of long-term 0g exposure, and the capability to mitigate the space radiation environment. 605:

In general, planetary orbiters and landers return much more detailed and comprehensive information than fly-by missions. Space probes have been placed into orbit around all the five planets known to the ancients: The first being

33: 32: 29: 1429:. Another fairly detailed vehicle system, designed and optimized for crewed Solar System exploration, "Discovery II", based on the DHe reaction but using hydrogen as reaction mass, has been described by a team from NASA's 34: 1126:

through Earth's atmosphere to reduce its speed until the parachute system could be deployed enabling a safe landing. Aerobraking does not require a thick atmosphere – for example most Mars landers use the technique, and

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The water would act as an insulator against the extreme cold assuming it was kept heated, whether by the Sun when traveling in the inner Solar System or by an on board power source when traveling further away from the

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Current space vehicles attempt to launch with all their fuel (propellants and energy supplies) on board that they will need for their entire journey, and current space structures are lifted from the Earth's surface.

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on Mars to handle production and storage of the propellant components necessary to launch and fly the Starships back to Earth, or perhaps to increase the mass that can be transported onward to destinations in the

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more fuel is needed to put both the spacecraft and the fuel required for its interplanetary journey into orbit. Thus, several techniques have been devised to reduce the fuel requirements of interplanetary travel.

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is small and decreases by the square of the distance from the Sun, but unlike rockets, solar sails require no fuel. Although the thrust is small, it continues as long as the Sun shines and the sail is deployed.

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Any major failure to a spacecraft en route is likely to be fatal, and even a minor one could have dangerous results if not repaired quickly, something difficult to accomplish in open space. The crew of the

31: 1222:, fuel depleted) mass. The main consequence is that mission velocities of more than a few times the velocity of the rocket motor exhaust (with respect to the vehicle) rapidly become impractical, as the 3097: 1654:

estimates that the reusability capability alone, on both the launch vehicle and the spacecraft associated with the Starship will reduce overall system costs per tonne delivered to Mars by at least two

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it is stationary compared to rest of the Solar System, which orbits the Sun. It may be used to send a spaceship or probe into the galaxy because the Sun revolves around the center of the Milky Way.

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The water would provide some additional protection against micrometeoroid impacts, provided the hull was compartmentalized so as to ensure any leak could be isolated to a small section of the hull.

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Finally, establishing completely self-sufficient colonies in other parts of the Solar System could, if feasible, prevent the human species from being exterminated by several possible events (see

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Wilson, John W; Cucinotta, F.A; Shinn, J.L; Simonsen, L.C; Dubey, R.R; Jordan, W.R; Jones, T.D; Chang, C.K; Kim, M.Y (1999). "Shielding from solar particle event exposures in deep space".

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of Jupiter. Some claim that such techniques may be the only way to provide rising standards of living without being stopped by pollution or by depletion of Earth's resources (for example

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As an example of the velocity changes involved, a spacecraft travelling from low Earth orbit to Mars using a simple trajectory must first undergo a change in speed (also known as a

2137:. Outside these windows the planets are essentially inaccessible from Earth with current technology. This constrains flights and limits rescue options in the case of an emergency. 3536:

Sinyak, Y; Grigoriev, A; Gaydadimov, V; Gurieva, T; Levinskih, M; Pokrovskii, B (2003). "Deuterium-free water (1H2O) in complex life-support systems of long-term space missions".

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The costs and risk of interplanetary travel receive a lot of publicity—spectacular examples include the malfunctions or complete failures of probes without a human crew, such as

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to avoid or minimize the expensive task of shipping components and fuel up from the Earth's surface, against the Earth's gravity (see "Using non-terrestrial resources", below).

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A spacecraft with an adequate water supply could carry the water under the hull, which could provide a considerable additional safety margin for the vessel and its occupants:

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fusion technologies can in principle achieve velocities far higher than needed for Solar System exploration, and fusion energy still awaits practical demonstration on Earth.

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s heliocentric velocity against its distance from the Sun, illustrating the use of gravity assist to accelerate the spacecraft by Jupiter, Saturn and Uranus. To observe

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article for a discussion of a number of other technologies that could, in the medium to longer term, be the basis of interplanetary missions. Unlike the situation with

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are mostly a lot further away, but most would not require lifting out of a strong gravity field and therefore should be much cheaper to use in space in the long term.

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Besides making travel faster or cost less, such improvements could also allow greater design "safety margins" by reducing the imperative to make spacecraft lighter.

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One of the main challenges in interplanetary travel is producing the very large velocity changes necessary to travel from one body to another in the Solar System.

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C. R. Williams et al., 'Realizing "2001: A Space Odyssey": Piloted Spherical Torus Nuclear Fusion Propulsion', 2001, 52 pages, NASA Glenn Research Center

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The Hohmann transfer applies to any two orbits, not just those with planets involved. For instance it is the most common way to transfer satellites into

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The low gravity of these moons would make them a cheaper source of water for space stations and planetary bases than lifting it up from Earth's surface.

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systems with much better fuel economy. Such systems would make it possible to travel much faster while keeping the fuel cost within acceptable limits.

1154:. Some are still just theoretical, but over time, several of the theoretical approaches have been tested on spaceflight missions. For example, the 891:

are rather sooty and therefore very hard to detect. Although carbonaceous chondrites are thought to be rare, some are very large and the suspected "

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There are also non-scientific motives for human spaceflight, such as adventure or the belief that humans have a spiritually fated destiny in space.

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Colombo, G.; Gaposchkin, E. M.; Grossi, M. D.; Weiffenbach, G. C. (1975). "The sky-hook: a shuttle-borne tool for low-orbital-altitude research".

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asteroids and understanding climate change. Support for scientific research is about four times higher than for human flight to the Moon or Mars.

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in preparation for the mission to Mars. They consider as one of the options a life support system generating drinking water with low content of

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Several technologies have been proposed which both save fuel and provide significantly faster travel than the traditional methodology of using

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waiting crewed spacecraft. The tanker would then transfer its fuel to the human crewed spacecraft for use on its interplanetary voyage. The

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Unfortunately hydrogen, along with other volatiles like carbon and nitrogen, are much less abundant than oxygen in the inner Solar System.

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M. L. Cosmo and E. C. Lorenzini, Tethers in Space Handbook, NASA Marshall Space Flight Center, Huntsville, Ala, USA, 3rd edition, 1997.

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The first Starship to Mars will carry a small propellant plant as a part of its cargo load. The plant will be expanded over multiple

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passed over Neptune's north pole resulting in an acceleration out of the plane of the ecliptic and reduced velocity away from the Sun.

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and NASA tested a few designs from 1959 to 1968. The NASA designs were conceived as replacements for the upper stages of the

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are highly dangerous, and are fatal within a very short timescale to humans unless they are protected by massive shielding.

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which generate electricity from the powerful magnetic fields of some planets (Jupiter has a very powerful magnetic field).

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in order to radically decrease the cost of spaceflight to interplanetary destinations is the placement and operation of a

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Novel methodologies of using energy at different locations or in different ways that can shorten transport time or reduce

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have made it possible to exploit many more features of the gravity fields of astronomical bodies and thus calculate even

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Simplified example of a gravitational slingshot: the spacecraft's velocity changes by up to twice the planet's velocity.

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Hohmann Transfer Orbit: a spaceship leaves from point 2 in Earth's orbit and arrives at point 3 in Mars' (not to scale).

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to be used in the vegetable gardens of orbital and planetary bases, reducing the need to lift food to them from Earth.

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spacecraft have landed on the surface of Venus, with the latter deploying balloons to the planet's atmosphere. The

2795: 2070:. Beyond the Van Allen belts, radiation levels generally decrease, but can fluctuate over time. These high energy 4434: 4316: 4054: 3819: 3312: 2247: 1343: 1208:, which sets the characteristic velocity available as a function of exhaust velocity and mass ratio, of initial ( 1118: 1054:). The use at this point multiplies up the effect of the delta-v, and gives a bigger effect than at other times. 2728: 4801: 4549: 4049: 4037: 4009: 2063: 303: 135: 115: 4268: 1460:, the barriers to fast interplanetary travel involve engineering and economics rather than any basic physics. 996: 4844: 4774: 4553: 4489: 4170: 4081: 3985: 3958: 3859: 1067: 983: 899: 338: 100: 1553:

It is possible to put stations or spacecraft on orbits that cycle between different planets, for example a

684:, landing on it briefly and returning grains of its surface material to Earth. Another ion-drive mission, 4870: 4702: 4601: 4563: 3997: 3916: 3854: 3212: 2541:

Capture Dynamics and Chaotic Motions in Celestial Mechanics: With the Construction of Low Energy Transfers

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Langley's Mars Ice Dome design from 2016 for a Mars base would use in-situ water to make a sort of space-

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using fuel. A few have even had small purpose-built solar sails for this use (for example Eurostar E3000

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L. Johnson, B. Gilchrist, R. D. Estes, and E. Lorenzini, "Overview of future NASA tether applications,"

2776: 2636: 2208: 2191: 2047: 1857: 1671:. One alternative to transport more mass on interplanetary trajectories is to use up nearly all of the 1453: 1430: 1342:. A more ambitious, nuclear-powered version was intended for a Jupiter mission without human crew, the 1199: 902:, argue that the vast majority of mankind eventually will live in space and will benefit from doing so. 760: 673: 3739: 2416: 491:. Orbiters and landers return more information than fly-by missions. Crewed flights have landed on the 2724: 1996: 4834: 4784: 4697: 4620: 4521: 4504: 4141: 4076: 4069: 3926: 3812: 3606: 3545: 3476: 3337: 2853: 2818: 2094: 2012: 1885: 1590: 1482:

Solar sails rely on the fact that light reflected from a surface exerts pressure on the surface. The

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Many science fiction stories feature detailed descriptions of how people could extract minerals from

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or indirectly by focusing solar radiation on boilers which produce steam to drive generators; and

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projects monitor the Solar System for objects that might come dangerously close to Earth, current

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Besides spinoffs, other practical motivations for interplanetary travel are more speculative. But

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Interplanetary Outpost: The Human and Technological Challenges of Exploring the Outer Planets

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propellant on launch, and then refill propellants in Earth orbit before firing the rocket to

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Bogar, Thomas J.; Bangham, Michal E.; Forward, Robert L.; Lewis, Mark J. (7 January 2000).

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is adaptable to a variety of mission-specific propulsion units of various low-thrust, high

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A powered slingshot is the use of a rocket engine at or around closest approach to a body (

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Currently, the only spacecraft to use a solar sail as the main method of propulsion is

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Hypersonic Airplane Space Tether Orbital Launch (HASTOL) System: Interim Study Results

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Fusion rockets are considered to be a likely source of interplanetary transport for a

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writers have a fairly good track record in predicting future technologies—for example

4895: 4539: 4456: 4387: 4350: 4190: 4111: 3975: 3970: 2940: 2892: 2668: 2391:"Myth-free space advocacy part I--The myth of innate exploratory and migratory urges" 2134: 2130: 2016: 1966: 1889: 1863:

Water ice would be very useful and is widespread on the moons of Jupiter and Saturn:

1766: 1579: 1538: 1498:". More recent light sail designs propose to boost the thrust by aiming ground-based 1414: 1347: 1306: 1267: 1266:. The energy replaces the chemical energy of the reactive chemicals in a traditional 1045: 1008: 839: 681: 257: 252: 247: 175: 150: 17: 3309:"Origin of How Steam Rockets can Reduce Space Transport Cost by Orders of Magnitude" 2555: 2008: 1226:(mass of payload and rocket without fuel) falls to below 10% of the entire rocket's 4860: 4717: 4596: 4531: 4200: 4185: 3886: 3881: 3282: 1985: 1871: 1790: 1644: 1542: 1318: 1155: 810: 795: 729: 718: 598: 553: 477: 473: 286: 2469: 1965:

can be used as a fuel (burned with non-terrestrial oxygen), or as a feedstock for

1611: 1401:

The electric propulsion missions already flown, or currently scheduled, have used

2278: 1726:

As an example of a funded project currently under development, a key part of the

1437:, with a ship initial mass of ~1700 metric tons, and payload fraction above 10%. 949:. Hohmann demonstrated that the lowest energy route between any two orbits is an 4424: 4290: 3980: 3963: 3835: 2274: 2071: 1903: 1672: 1554: 1302: 1114: 540: 469: 211: 128: 63: 2725:"The Physics of Interstellar Travel : Official Website of Dr. Michio Kaku" 4558: 4466: 4409: 4369: 4163: 3864: 3184: 2228:

Interplanetary Flight: an introduction to astronautics. London: Temple Press,

2133:

reasons, economic spacecraft travel to other planets is only practical within

1978: 1909:

The water would provide some additional protection against ionizing radiation;

1853: 1714: 1469: 1366: 1298: 1138: 880: 592: 586: 298: 262: 188: 95: 2492: 2121:

mission survived despite an explosion caused by a faulty oxygen tank (1970).

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The original concept relied only on radiation from the Sun – for example in

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Many astronomers, geologists and biologists believe that exploration of the

668: 648: 619: 580: 574: 293: 206: 40: 3626: 3565: 3522: 2809:

Edwards, Bradley C. (2004). "A Space Elevator Based Exploration Strategy".

1525:, there have been several proposals for their use within the Solar System. 779: 3189:(video). IAC67, Guadalajara, Mexico: SpaceX. Event occurs at 9:20–10:10. 1589:

A terrestrial space elevator is beyond our current technology, although a

914:

than the planet to which the spacecraft is travelling (in accordance with

3278:"Elon Musk scales up his ambitions, considering going "well beyond" Mars" 1927: 1640: 1586:", "space bridges", "space lifts", "space ladders" and "orbital towers". 1357:

A NASA multi-center Technology Applications Assessment Team led from the

1278: 1255: 1227: 1223: 959: 858: 846: 799: 664: 611: 488: 3090:"60,000 miles up: Space elevator could be built by 2035, says new study" 1066:

were first proposed (1925) and were slow, expensive and unreliable when

3364: 2884: 2147: 1974: 1970: 1962: 1806: 1339: 1335: 1020: 954: 950: 926: 791: 691: 623: 548: 461: 3308: 2830: 2417:"A Space Roadmap: Mine the Sky, Defend the Earth, Settle the Universe" 1365:(LEO), of up to 24 months duration for a crew of up to six. Although 1102: 70: 4875: 4642: 4382: 4246: 3248: 2243:"NASA Spacecraft Embarks on Historic Journey Into Interstellar Space" 2086: 1798: 1727: 1529: 1263: 1259: 735:

No crewed missions have been sent to any planet of the Solar System.

714: 633: 2162: – Cancer causing exposure to ionizing radiation in spaceflight 2085:

are searching for methods of reducing the risk of radiation-induced

694:(July 2011 – September 2012) and later moved on to the dwarf planet 652:, March 2011), and have returned data about these bodies and their 543:

have flown by all of the observed planets of the Solar System from

2007: 1995: 1902:

The water would absorb and conduct solar energy, thus acting as a

1836: 1830: 1606: 1511: 1507: 1503: 1499: 1473: 1101: 995: 987: 936: 778: 748: 607: 558: 528: 522: 500: 480: 457: 1162:. These improved technologies typically focus on one or more of: 4865: 3400: 2683:

NASA/JSC Multi-Mission Space Exploration Vehicle, Jan. 26, 2011.

1923: 1750:

as more equipment arrives, is installed, and placed into mostly-

1731: 1635:

is designed to be fully and rapidly reusable, making use of the

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For many years economical interplanetary travel meant using the

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The End of Astronauts: Why Robots Are the Future of Exploration

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of this type are confined to travel between the planets of the

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Siniak IuE, Turusov VS; Grigorev, AI; et al. (2003). "".

2183: – Hypothetical travel between stars or planetary systems 2105: 1774: 1258:, is heated to a high temperature, and then expands through a 3360:"Report: NASA needs better handle on health hazards for Mars" 1961:, and the range of possible uses is even wider. For example, 1683:

trajectory. These propellants could be stored on orbit at a

1623:

engineeringly feasible using presently available materials".

3334:""Neofuel" -interplanetary travel using off-earth resources" 3123:"SpaceX reveals ITS Mars game changer via colonization plan" 2493:"Basics of Space Flight Section I. The Environment of Space" 2420: 2200: – For health conditions encountered during spaceflight 1984:

Even unprocessed rock may be useful as rocket propellant if

1121:

of the target planet to slow down. It was first used on the

1110:

to aerobrake by skimming the atmosphere (artistic rendition)

2062:

and the protection of Earth's magnetosphere, it enters the

3333: 2927:

E. M. Levin, "Dynamic Analysis of Space Tether Missions",

771:

was terminated due to NASA budget cuts in the late 1960s.

2844:

Moravec, H. (1977). "A non-synchronous orbital skyhook".

2693:"NASA Team Produces NAUTILUS-X, A Fascinating Spacecraft" 887:

are crude and untested. To make the task more difficult,

3155:"SpaceX advances drive for Mars rocket via Raptor power" 2961:"Hypersonic Airplane Space Tether Orbital Launch System" 2671:– NASA's Multi-mission Space Exploration Vehicle Concept 2440:(1st ed.). Elsevier Butterworth-Heinemann. p. 2150: – Measure of amount of effort to change trajectory 2164:

Pages displaying short descriptions of redirect targets

1593:

could theoretically be built using existing materials.

584:

have left the Solar System as of 8 December 2018 while

1478:

NASA illustration of a solar-sail propelled spacecraft

663:

mission in 2000 orbited the large near-Earth asteroid

1817:

it to facilitate long-term storage and ultimate use.

2419:. Space Studies Institute, Princeton. Archived from 1992:

Design requirements for crewed interplanetary travel

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of space ships, space stations and planetary bases.

2968:Research Grant No. 07600-018l Phase I Final Report 2156: – Medical issues associated with spaceflight 1521:Although most articles about light sails focus on 48:Crewed or uncrewed travel between stars or planets 2997:"Why we'll probably never build a space elevator" 2177: – Reusable super heavy-lift launch vehicle 2000:In the artistic vision, the spacecraft provides 1957:in some of the planets, moons and comets of the 1870:Non-terrestrial power supplies could be used to 1032:as slingshots in journeys to the outer planets. 3116: 3114: 1846:Non-terrestrial sources of energy and materials 1019:The gravitational slingshot technique uses the 713:have landed on the surface of Mars and several 1874:water ice into oxygen and hydrogen for use in 495:and have been planned, from time to time, for 4907:Discovery and exploration of the Solar System 4658: 3820: 2334:Kennedy, Brian; Tyson, Alec (July 20, 2023). 2171: – Spaceflight with a crew or passengers 1761:will take advantage of the large supplies of 1618:A skyhook is a theoretical class of orbiting 519:Current achievements in interplanetary travel 422: 8: 2792:"The Space Elevator Comes Closer to Reality" 2211: – Method used to accelerate spacecraft 1977:could be a valuable feedstock for producing 1078:. Paths have been calculated which link the 875:like the one which may have resulted in the 2750:"Abstracts of NASA articles on solar sails" 2306:"The Scientific Case for Human Spaceflight" 1789:will process the raw materials by means of 853:(unhampered by clouds) and the very strong 838:) and many aspects of computer technology ( 4665: 4651: 4643: 4126: 3827: 3813: 3805: 2437:Orbital Mechanics for Engineering Students 1953:Scientists expect to find a vast range of 1321:was a very successful test of a prototype 1082:of the various planets into the so-called 1070:were developed (1959). Recent advances in 898:Some scientists, including members of the 895:" may have been a carbonaceous chondrite. 849:and energy from sources including orbital 755:, originally introduced by U.S. President 429: 415: 227: 193: 50: 1627:Launch vehicle and spacecraft reusability 1514:can also help a light-sail spacecraft to 1293:systems use an external source such as a 1234:Nuclear thermal and solar thermal rockets 3242:"Making Humans a Multiplanetary Species" 2970:. NASA Institute for Advanced Concepts. 1658:over what NASA had previously achieved. 1639:that was developed during 2011–2018 for 1314:missions took 3 days in each direction. 1237: 832:geosynchronous communications satellites 44:as it flies by Earth en route to Mercury 26: 4312:Effect of spaceflight on the human body 2221: 2154:Effect of spaceflight on the human body 1709:-structure spacecraft propelled by six 1425:One proposal using a fusion rocket was 1204:All rocket concepts are limited by the 1146:Improved technologies and methodologies 1106:Apollo command module flying at a high 871:). One of these possible events is an 743:, however, landed twelve people on the 557:probe having flown by the dwarf planet 62: 4334:Psychological and sociological effects 3760:"Launch Windows: Timing is Everything" 3210: 3186:Making Humans a Multiplanetary Species 3153:Belluscio, Alejandro G. (2014-03-07). 2918:, vol. 24, no. 8, pp. 1055–1063, 1999. 1930:can be found. Possible uses include: 1922:Oxygen is a common constituent of the 1151: 1133:Aerobraking converts the spacecraft's 1130:is only about 1% as thick as Earth's. 728:successfully landed on Saturn's moon, 3372:from the original on January 30, 2019 2846:Journal of the Astronautical Sciences 2359:Aldrin, Buzz; Wachhorst, Wyn (2004). 877:Cretaceous–Paleogene extinction event 818:least as useful in other activities ( 7: 3028:"Why Don't We Have Space Elevators?" 2255:from the original on 20 October 2019 1722:Propellant plant on a celestial body 1614:first proposed by E. Sarmont in 1990 1158:mission was a successful test of an 1142:material available near the target. 767:mission, but was cancelled when the 701:Remotely controlled landers such as 568:currently orbiting the dwarf planet 3790:. New York: Springer. p. 288. 3469:International Cosmic Ray Conference 3007:from the original on 10 August 2014 1541:communications satellites built by 4043:Weather and environment monitoring 3088:Templeton, Graham (6 March 2014). 3038:from the original on 6 August 2014 2466:"Rockets and Space Transportation" 759:and put into practice through the 25: 3490:from the original on 4 March 2016 3358:Dunn, Marcia (October 29, 2015). 3069:from the original on 2 March 2014 775:Reasons for interplanetary travel 690:, has orbited the large asteroid 4626: 4616: 4615: 2995:Dvorsky, G. (13 February 2013). 2036:NASA Office of Inspector General 1821:Using extraterrestrial resources 1242:Sketch of nuclear thermal rocket 1084:Interplanetary Transport Network 970:, after first being "parked" in 398: 4087:Space launch market competition 3722:from the original on 2016-03-08 3716:"yarchive.net/space/spacecraft" 3697:from the original on 2016-12-18 3647:from the original on 2010-08-21 3437:. 18 March 2015. Archived from 3340:from the original on 2006-11-16 3315:from the original on 2017-11-16 3290:from the original on 2016-09-20 3193:from the original on 2021-12-11 3183:Elon Musk (27 September 2016). 3165:from the original on 2015-09-11 3135:from the original on 2019-07-13 3100:from the original on 2014-04-12 3057:Scharr, Jillian (29 May 2013). 2977:from the original on 2013-08-21 2769:"Buzz Aldrin's Roadmap To Mars" 2731:from the original on 2019-07-08 2647:from the original on 2024-02-07 2618:from the original on 2017-11-17 2520:from the original on 2019-10-22 2316:from the original on 2019-04-06 2204:Space travel in science fiction 677:in 2005 also orbited the small 572:. The most distant spacecraft, 535:after its nearly 10-year voyage 4324:Health threat from cosmic rays 3431:"Radiation Belts -- Fun Facts" 2929:American Astronautical Society 2544:. Princeton University Press. 2187:List of interplanetary voyages 2160:Health threat from cosmic rays 885:asteroid deflection strategies 1: 3619:10.1016/S1350-4487(99)00063-3 3558:10.1016/S0094-5765(02)00013-9 2767:Aldrin, B; Noland, D (2005). 1406:chemically powered vehicles. 1062:Computers did not exist when 3251:. 2016-09-27. Archived from 3121:Bergin, Chris (2016-09-27). 3026:Feltman, R. (7 March 2013). 2931:, Washington, DC, USA, 2007. 2637:"Nuclear Thermal Propulsion" 2277:; Goldsmith, Donald (2022). 1852:clouds), either directly by 1827:In-situ resource utilization 1769:on Mars, mining the water (H 1230:(mass of rocket with fuel). 1215:, including fuel) to final ( 1174:in-situ resource utilization 1137:into heat, so it requires a 906:Economical travel techniques 753:Vision for Space Exploration 4440:Self-replicating spacecraft 4276:International Space Station 3666:"islandone.org/Settlements" 3276:Berger, Eric (2016-09-18). 2794:. space.com. Archived from 2083:Russian Academy of Sciences 1687:, or carried to orbit in a 1379:International Space Station 1206:Tsiolkovsky rocket equation 804:List of Solar System probes 769:Apollo Applications Program 642:, 2004), and most recently 602:are on course to leave it. 371:List of space organizations 4923: 4688:Interplanetary spaceflight 3954:Space Liability Convention 3641:"nature.com/embor/journal" 3391:Staff (October 29, 2015). 2916:Advances in Space Research 2811:AIP Conference Proceedings 1824: 1637:SpaceX reusable technology 1600: 1565: 1506:at the sail. Ground-based 1467: 1359:Johnson Spaceflight Center 1197: 1043: 981: 698:, arriving in March 2015. 464:, usually within a single 442:Interplanetary spaceflight 4610: 4317:Space adaptation syndrome 2491:Dave Doody (2004-09-15). 2248:Jet Propulsion Laboratory 2194: – Proposed concepts 1969:processes such as making 1696:On-orbit tanker transfers 1344:Jupiter Icy Moons Orbiter 1254:a working fluid, usually 4050:Communications satellite 3786:Seedhouse, Erik (2012). 3217:: CS1 maint: location ( 2516:. discovermagazine.com. 2389:Schwartz, James (2017). 2310:Astronomy and Geophysics 2064:Van Allen radiation belt 1730:SpaceX has designed for 1275:Atomic Energy Commission 1194:Improved rocket concepts 1068:gravitational slingshots 4812:Trans-Neptunian objects 4554:reusable launch systems 4171:Extravehicular activity 4082:Commercial use of space 3986:Militarisation of space 3959:Registration Convention 3875:Accidents and incidents 2434:Curtis, Howard (2005). 2304:Crawford, I.A. (1998). 1882:Nuclear thermal rockets 1759:SpaceX propellant plant 1397:Fission powered rockets 1172:Using solar energy and 1090:if humanity develops a 1076:lower-cost trajectories 1064:Hohmann transfer orbits 984:gravitational slingshot 978:Gravitational slingshot 900:Space Studies Institute 889:carbonaceous chondrites 711:Mars Exploration Rovers 101:Timeline of spaceflight 4871:National Space Society 4703:Planetary habitability 4602:Mission control center 4564:Non-rocket spacelaunch 3998:Billionaire space race 3691:"iss.jaxa.jp/iss/kibo" 3599:Radiation Measurements 2365:Mechanical Engineering 2102:coronal mass ejections 2058:Once a vehicle leaves 2019: 2005: 1858:electrodynamic tethers 1840: 1615: 1532:which was launched by 1479: 1442:planetary civilization 1248:nuclear thermal rocket 1243: 1111: 1016: 993: 953:"orbit" which forms a 947:Hohmann transfer orbit 942: 787: 536: 405:Spaceflight portal 321:Non-rocket spacelaunch 91:History of spaceflight 75: 45: 4881:The Planetary Society 4452:Spacecraft propulsion 3902:European Space Agency 2538:Belbruno, E. (2004). 2415:Valentine, L (2002). 2361:"The Urge to Explore" 2209:Spacecraft propulsion 2192:Human mission to Mars 2048:human mission to Mars 2040:health hazards report 2034:In October 2015, the 2011: 1999: 1886:Solar thermal rockets 1834: 1752:autonomous production 1610: 1477: 1454:spacecraft propulsion 1431:Glenn Research Center 1391:near-Earth asteroidal 1241: 1200:Spacecraft propulsion 1105: 999: 991: 940: 782: 761:Constellation program 747:and returned them to 526: 446:interplanetary travel 74: 37: 18:Interplanetary travel 4902:Spaceflight concepts 4828:Terraforming targets 4758:Colonization targets 4698:Intergalactic travel 4077:Satellite navigation 3579:popularmechanics.com 2135:certain time windows 2028:Life support systems 2013:Deep Space Transport 1936:life support systems 1612:Non-rotating skyhook 1591:lunar space elevator 1252:solar thermal rocket 806:gives a full list). 783:Space colony on the 4693:Interstellar travel 4462:Electric propulsion 4149:Life-support system 4033:Imagery and mapping 3993:Private spaceflight 3611:1999RadM...30..361W 3550:2003AcAau..52..575S 3511:Aviakosm Ekolog Med 3481:2005ICRC....2..433M 3159:NASAspaceflight.com 3128:NASASpaceFlight.com 2858:1977JAnSc..25..307M 2823:2004AIPC..699..854E 2340:Pew Research Center 2181:Interstellar travel 2095:isotope of hydrogen 2066:, a region of high 2004:by spinning (1989). 1876:bipropellant rocket 1773:O) from subsurface 1692:loaded for launch. 1662:Staging propellants 1656:orders of magnitude 1603:Skyhook (structure) 1523:interstellar travel 1458:interstellar travel 1333:main-belt asteroids 1291:Electric propulsion 1286:Electric propulsion 1092:space-based economy 968:geostationary orbit 879:. Although various 679:near-Earth asteroid 243:Apollo Lunar Module 4739:McKendree cylinder 4708:Space and survival 4674:Space colonization 4415:Robotic spacecraft 4341:Space and survival 4196:Space colonization 4092:Space architecture 3944:Outer Space Treaty 3758:NSE (2023-03-29). 3745:2004-03-28 at the 3584:2007-08-14 at the 3441:on 3 November 2021 3411:on October 9, 2022 2946:2016-04-27 at the 2885:10.1007/bf02148280 2698:2013-05-26 at the 2020: 2006: 2002:artificial gravity 1959:outer Solar System 1841: 1741:outer Solar System 1616: 1484:radiation pressure 1480: 1244: 1112: 1017: 994: 943: 916:Kepler's Third Law 788: 765:Manned Venus Flyby 654:natural satellites 537: 200:Robotic spacecraft 76: 46: 4889: 4888: 4640: 4639: 4587:Flight controller 4364: 4363: 4122:Human spaceflight 4097:Space exploration 4023:Earth observation 3764:New Space Economy 3538:Acta Astronautica 3032:Popular Mechanics 2831:10.1063/1.1649650 2790:David, D (2002). 2773:Popular Mechanics 2702:February 21, 2011 2395:Acta Astronautica 2283:. Belknap Press. 2169:Human spaceflight 2044:human spaceflight 1955:organic compounds 1944:rocket propellant 1777:and collecting CO 1689:propellant tanker 1647:launch vehicles. 1620:tether propulsion 1448:Exotic propulsion 1183:per unit mass of 1152:Hohmann transfers 1040:Powered slingshot 933:Hohmann transfers 439: 438: 333:Spaceflight types 277: 276: 234:Crewed spacecraft 226: 225: 141:Earth observation 35: 16:(Redirected from 4914: 4744:O'Neill cylinder 4713:Space settlement 4667: 4660: 4653: 4644: 4630: 4619: 4618: 4329:Space psychology 4154:Animals in space 4127: 4107:Space technology 3949:Rescue Agreement 3829: 3822: 3815: 3806: 3801: 3774: 3773: 3771: 3770: 3755: 3749: 3740:uplink.space.com 3737: 3731: 3730: 3728: 3727: 3712: 3706: 3705: 3703: 3702: 3687: 3681: 3680: 3678: 3677: 3668:. 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Archived from 2746: 2740: 2739: 2737: 2736: 2721: 2715: 2709: 2703: 2690: 2684: 2678: 2672: 2666: 2660: 2659: 2653: 2652: 2633: 2627: 2626: 2624: 2623: 2612:www.jpl.nasa.gov 2604: 2598: 2597: 2595: 2594: 2588: 2582:. Archived from 2581: 2573: 2567: 2566: 2564: 2563: 2554:. Archived from 2535: 2529: 2528: 2526: 2525: 2510: 2504: 2503: 2501: 2500: 2488: 2482: 2481: 2479: 2477: 2468:. Archived from 2462: 2456: 2455: 2431: 2425: 2424: 2412: 2406: 2405: 2403: 2402: 2386: 2380: 2379: 2377: 2376: 2356: 2350: 2349: 2347: 2346: 2331: 2325: 2324: 2322: 2321: 2301: 2295: 2294: 2271: 2265: 2264: 2262: 2260: 2239: 2233: 2230:Arthur C. Clarke 2226: 2165: 1894:specific impulse 1888:could use it as 1795:Sabatier process 1685:propellant depot 1492:Arthur C. Clarke 1427:Project Daedalus 1371:specific impulse 1167:Space propulsion 1128:Mars' atmosphere 1006: 869:Human extinction 836:Arthur C. Clarke 785:O'Neill cylinder 751:. The American 539:Remotely guided 466:planetary system 431: 424: 417: 403: 402: 401: 228: 217:Cargo spacecraft 194: 51: 36: 21: 4922: 4921: 4917: 4916: 4915: 4913: 4912: 4911: 4892: 4891: 4890: 4885: 4849: 4823: 4765:Lagrange points 4753: 4722: 4676: 4671: 4641: 4636: 4606: 4573: 4545:Escape velocity 4526: 4478: 4445:Space telescope 4398:Reentry capsule 4360: 4300: 4205: 4176:Overview effect 4159:Bioastronautics 4116: 4004: 3838: 3833: 3798: 3785: 3782: 3780:Further reading 3777: 3768: 3766: 3757: 3756: 3752: 3747:Wayback Machine 3738: 3734: 3725: 3723: 3714: 3713: 3709: 3700: 3698: 3689: 3688: 3684: 3675: 3673: 3664: 3663: 3659: 3650: 3648: 3639: 3638: 3634: 3596: 3595: 3591: 3586:Wayback Machine 3577: 3573: 3535: 3534: 3530: 3508: 3507: 3503: 3493: 3491: 3487: 3464: 3459: 3458: 3454: 3444: 3442: 3429: 3428: 3424: 3414: 3412: 3408: 3395: 3390: 3389: 3385: 3375: 3373: 3357: 3356: 3352: 3343: 3341: 3332: 3331: 3327: 3318: 3316: 3307: 3306: 3302: 3293: 3291: 3275: 3274: 3270: 3261: 3259: 3255: 3244: 3240: 3239: 3226: 3209: 3196: 3194: 3182: 3181: 3177: 3168: 3166: 3152: 3151: 3147: 3138: 3136: 3120: 3119: 3112: 3103: 3101: 3087: 3086: 3082: 3072: 3070: 3063:Huffington Post 3056: 3055: 3051: 3041: 3039: 3025: 3024: 3020: 3010: 3008: 2994: 2993: 2989: 2980: 2978: 2974: 2963: 2958: 2957: 2953: 2948:Wayback Machine 2939: 2935: 2926: 2922: 2913: 2909: 2904: 2900: 2870: 2869: 2865: 2843: 2842: 2838: 2808: 2807: 2803: 2789: 2788: 2784: 2766: 2765: 2761: 2748: 2747: 2743: 2734: 2732: 2723: 2722: 2718: 2710: 2706: 2700:Wayback Machine 2691: 2687: 2679: 2675: 2667: 2663: 2650: 2648: 2635: 2634: 2630: 2621: 2619: 2606: 2605: 2601: 2592: 2590: 2586: 2579: 2575: 2574: 2570: 2561: 2559: 2552: 2537: 2536: 2532: 2523: 2521: 2514:"Gravity's Rim" 2512: 2511: 2507: 2498: 2496: 2495:. .jpl.nasa.gov 2490: 2489: 2485: 2475: 2473: 2472:on July 1, 2007 2464: 2463: 2459: 2452: 2433: 2432: 2428: 2414: 2413: 2409: 2400: 2398: 2388: 2387: 2383: 2374: 2372: 2358: 2357: 2353: 2344: 2342: 2333: 2332: 2328: 2319: 2317: 2303: 2302: 2298: 2291: 2273: 2272: 2268: 2258: 2256: 2241: 2240: 2236: 2227: 2223: 2219: 2214: 2175:SpaceX Starship 2163: 2143: 2127: 2114: 2060:low Earth orbit 2056: 2025: 1994: 1829: 1823: 1812: 1804: 1780: 1772: 1767:water resources 1724: 1707:stainless steel 1703:SpaceX Starship 1698: 1677:escape velocity 1669:rocket equation 1664: 1633:SpaceX Starship 1629: 1605: 1599: 1570: 1564: 1551: 1494:'s 1965 story " 1472: 1466: 1450: 1412: 1399: 1376: 1363:low Earth orbit 1295:nuclear reactor 1288: 1236: 1221: 1214: 1202: 1196: 1185:space transport 1148: 1108:angle of attack 1100: 1080:Lagrange points 1060: 1048: 1042: 1026:Voyager program 1004: 986: 980: 972:low Earth orbit 935: 908: 893:dinosaur-killer 873:asteroid impact 828:science fiction 777: 639:Cassini/Huygens 521: 468:. In practice, 456:travel between 435: 399: 397: 392: 391: 372: 364: 363: 334: 326: 325: 316:Escape velocity 311:launch vehicles 289: 279: 278: 273: 272: 236: 222: 221: 202: 191: 181: 180: 131: 121: 120: 86: 49: 27: 23: 22: 15: 12: 11: 5: 4920: 4918: 4910: 4909: 4904: 4894: 4893: 4887: 4886: 4884: 4883: 4878: 4873: 4868: 4863: 4857: 4855: 4851: 4850: 4848: 4847: 4842: 4837: 4831: 4829: 4825: 4824: 4822: 4821: 4816: 4815: 4814: 4809: 4804: 4799: 4798: 4797: 4787: 4782: 4777: 4767: 4761: 4759: 4755: 4754: 4752: 4751: 4749:Stanford torus 4746: 4741: 4736: 4730: 4728: 4727:Space habitats 4724: 4723: 4721: 4720: 4715: 4710: 4705: 4700: 4695: 4690: 4684: 4682: 4678: 4677: 4672: 4670: 4669: 4662: 4655: 4647: 4638: 4637: 4635: 4634: 4623: 4611: 4608: 4607: 4605: 4604: 4599: 4594: 4592:Ground station 4589: 4583: 4581: 4579:Ground segment 4575: 4574: 4572: 4571: 4566: 4561: 4556: 4547: 4542: 4536: 4534: 4528: 4527: 4525: 4524: 4519: 4514: 4512:Interplanetary 4509: 4508: 4507: 4505:Geosynchronous 4502: 4492: 4486: 4484: 4480: 4479: 4477: 4476: 4475: 4474: 4472:Gravity assist 4469: 4464: 4459: 4449: 4448: 4447: 4442: 4437: 4432: 4427: 4422: 4412: 4407: 4406: 4405: 4403:Service module 4400: 4395: 4393:Orbital module 4385: 4380: 4378:Launch vehicle 4374: 4372: 4366: 4365: 4362: 4361: 4359: 4358: 4356:Space sexology 4353: 4348: 4346:Space medicine 4343: 4338: 4337: 4336: 4326: 4321: 4320: 4319: 4308: 4306: 4302: 4301: 4299: 4298: 4293: 4288: 4283: 4278: 4273: 4272: 4271: 4261: 4256: 4255: 4254: 4249: 4239: 4234: 4229: 4224: 4219: 4213: 4211: 4207: 4206: 4204: 4203: 4198: 4193: 4188: 4183: 4181:Weightlessness 4178: 4173: 4168: 4167: 4166: 4161: 4156: 4146: 4145: 4144: 4133: 4131: 4124: 4118: 4117: 4115: 4114: 4109: 4104: 4102:Space research 4099: 4094: 4089: 4084: 4079: 4074: 4073: 4072: 4067: 4062: 4057: 4047: 4046: 4045: 4040: 4038:Reconnaissance 4035: 4030: 4020: 4014: 4012: 4006: 4005: 4003: 4002: 4001: 4000: 3990: 3989: 3988: 3983: 3978: 3968: 3967: 3966: 3961: 3956: 3951: 3946: 3936: 3935: 3934: 3929: 3924: 3919: 3914: 3909: 3907:European Union 3904: 3899: 3894: 3884: 3879: 3878: 3877: 3872: 3867: 3862: 3852: 3846: 3844: 3840: 3839: 3834: 3832: 3831: 3824: 3817: 3809: 3803: 3802: 3797:978-1441997470 3796: 3781: 3778: 3776: 3775: 3750: 3732: 3707: 3682: 3657: 3632: 3605:(3): 361–382. 3589: 3571: 3528: 3501: 3452: 3422: 3383: 3350: 3325: 3300: 3268: 3224: 3175: 3145: 3110: 3080: 3049: 3018: 2987: 2951: 2933: 2920: 2907: 2898: 2863: 2852:(4): 307–322. 2836: 2801: 2798:on 2010-11-04. 2782: 2779:on 2006-12-11. 2759: 2756:on 2008-03-11. 2741: 2716: 2704: 2685: 2673: 2661: 2628: 2608:"Deep Space 1" 2599: 2568: 2550: 2530: 2505: 2483: 2457: 2451:978-0750661690 2450: 2426: 2423:on 2007-02-23. 2407: 2381: 2351: 2326: 2296: 2290:978-0674257726 2289: 2266: 2234: 2220: 2218: 2215: 2213: 2212: 2206: 2201: 2198:Space medicine 2195: 2189: 2184: 2178: 2172: 2166: 2157: 2151: 2144: 2142: 2139: 2126: 2125:Launch windows 2123: 2113: 2110: 2081:Scientists of 2055: 2052: 2046:, including a 2024: 2021: 1993: 1990: 1988:are employed. 1948: 1947: 1939: 1920: 1919: 1918: 1917: 1914: 1910: 1907: 1897: 1879: 1868: 1825:Main article: 1822: 1819: 1810: 1802: 1787:chemical plant 1778: 1770: 1763:carbon dioxide 1736:physical plant 1723: 1720: 1711:Raptor engines 1697: 1694: 1663: 1660: 1628: 1625: 1601:Main article: 1598: 1595: 1580:counterweights 1575:vicious circle 1568:Space elevator 1566:Main article: 1563: 1562:Space elevator 1560: 1550: 1547: 1468:Main article: 1465: 1462: 1449: 1446: 1419:nuclear fusion 1417:, powered by 1415:Fusion rockets 1411: 1410:Fusion rockets 1408: 1403:solar electric 1398: 1395: 1374: 1319:Deep Space One 1287: 1284: 1235: 1232: 1219: 1212: 1198:Main article: 1195: 1192: 1188: 1187: 1177: 1170: 1147: 1144: 1135:kinetic energy 1123:Apollo program 1099: 1096: 1059: 1056: 1044:Main article: 1041: 1038: 982:Main article: 979: 976: 934: 931: 907: 904: 855:magnetic field 776: 773: 757:George W. Bush 741:Apollo program 661:NEAR Shoemaker 527:The plains of 520: 517: 487:, and several 437: 436: 434: 433: 426: 419: 411: 408: 407: 394: 393: 390: 389: 384: 379: 377:Space agencies 373: 370: 369: 366: 365: 362: 361: 356: 351: 349:Interplanetary 346: 341: 335: 332: 331: 328: 327: 324: 323: 318: 313: 301: 296: 290: 285: 284: 281: 280: 275: 274: 271: 270: 265: 260: 258:Space stations 255: 250: 248:Space capsules 245: 240: 237: 232: 231: 224: 223: 220: 219: 214: 209: 203: 198: 197: 192: 187: 186: 183: 182: 179: 178: 173: 168: 163: 158: 153: 148: 143: 138: 136:Communications 132: 127: 126: 123: 122: 119: 118: 113: 111:Lunar missions 108: 103: 98: 93: 87: 82: 81: 78: 77: 67: 66: 60: 59: 47: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4919: 4908: 4905: 4903: 4900: 4899: 4897: 4882: 4879: 4877: 4874: 4872: 4869: 4867: 4864: 4862: 4859: 4858: 4856: 4854:Organizations 4852: 4846: 4843: 4841: 4838: 4836: 4833: 4832: 4830: 4826: 4820: 4817: 4813: 4810: 4808: 4805: 4803: 4800: 4796: 4793: 4792: 4791: 4788: 4786: 4783: 4781: 4778: 4776: 4773: 4772: 4771: 4768: 4766: 4763: 4762: 4760: 4756: 4750: 4747: 4745: 4742: 4740: 4737: 4735: 4732: 4731: 4729: 4725: 4719: 4716: 4714: 4711: 4709: 4706: 4704: 4701: 4699: 4696: 4694: 4691: 4689: 4686: 4685: 4683: 4681:Core concepts 4679: 4675: 4668: 4663: 4661: 4656: 4654: 4649: 4648: 4645: 4633: 4629: 4624: 4622: 4613: 4612: 4609: 4603: 4600: 4598: 4595: 4593: 4590: 4588: 4585: 4584: 4582: 4580: 4576: 4570: 4567: 4565: 4562: 4560: 4557: 4555: 4551: 4548: 4546: 4543: 4541: 4540:Direct ascent 4538: 4537: 4535: 4533: 4529: 4523: 4522:Intergalactic 4520: 4518: 4515: 4513: 4510: 4506: 4503: 4501: 4498: 4497: 4496: 4493: 4491: 4488: 4487: 4485: 4481: 4473: 4470: 4468: 4465: 4463: 4460: 4458: 4457:Rocket engine 4455: 4454: 4453: 4450: 4446: 4443: 4441: 4438: 4436: 4433: 4431: 4428: 4426: 4423: 4421: 4418: 4417: 4416: 4413: 4411: 4408: 4404: 4401: 4399: 4396: 4394: 4391: 4390: 4389: 4388:Space capsule 4386: 4384: 4381: 4379: 4376: 4375: 4373: 4371: 4367: 4357: 4354: 4352: 4351:Space nursing 4349: 4347: 4344: 4342: 4339: 4335: 4332: 4331: 4330: 4327: 4325: 4322: 4318: 4315: 4314: 4313: 4310: 4309: 4307: 4305:Health issues 4303: 4297: 4294: 4292: 4289: 4287: 4284: 4282: 4279: 4277: 4274: 4270: 4267: 4266: 4265: 4262: 4260: 4259:Space Shuttle 4257: 4253: 4250: 4248: 4245: 4244: 4243: 4240: 4238: 4235: 4233: 4230: 4228: 4225: 4223: 4220: 4218: 4215: 4214: 4212: 4208: 4202: 4199: 4197: 4194: 4192: 4191:Space tourism 4189: 4187: 4184: 4182: 4179: 4177: 4174: 4172: 4169: 4165: 4162: 4160: 4157: 4155: 4152: 4151: 4150: 4147: 4143: 4140: 4139: 4138: 4135: 4134: 4132: 4128: 4125: 4123: 4119: 4113: 4112:Space weather 4110: 4108: 4105: 4103: 4100: 4098: 4095: 4093: 4090: 4088: 4085: 4083: 4080: 4078: 4075: 4071: 4068: 4066: 4063: 4061: 4058: 4056: 4053: 4052: 4051: 4048: 4044: 4041: 4039: 4036: 4034: 4031: 4029: 4026: 4025: 4024: 4021: 4019: 4016: 4015: 4013: 4011: 4007: 3999: 3996: 3995: 3994: 3991: 3987: 3984: 3982: 3979: 3977: 3976:Space command 3974: 3973: 3972: 3971:Space warfare 3969: 3965: 3962: 3960: 3957: 3955: 3952: 3950: 3947: 3945: 3942: 3941: 3940: 3937: 3933: 3932:United States 3930: 3928: 3925: 3923: 3920: 3918: 3915: 3913: 3910: 3908: 3905: 3903: 3900: 3898: 3895: 3893: 3890: 3889: 3888: 3885: 3883: 3880: 3876: 3873: 3871: 3868: 3866: 3863: 3861: 3858: 3857: 3856: 3853: 3851: 3850:Astrodynamics 3848: 3847: 3845: 3841: 3837: 3830: 3825: 3823: 3818: 3816: 3811: 3810: 3807: 3799: 3793: 3789: 3784: 3783: 3779: 3765: 3761: 3754: 3751: 3748: 3744: 3741: 3736: 3733: 3721: 3717: 3711: 3708: 3696: 3692: 3686: 3683: 3672:on 2016-04-05 3671: 3667: 3661: 3658: 3646: 3642: 3636: 3633: 3628: 3624: 3620: 3616: 3612: 3608: 3604: 3600: 3593: 3590: 3587: 3583: 3580: 3575: 3572: 3567: 3563: 3559: 3555: 3551: 3547: 3544:(7): 575–80. 3543: 3539: 3532: 3529: 3524: 3520: 3516: 3512: 3505: 3502: 3486: 3482: 3478: 3474: 3470: 3463: 3456: 3453: 3440: 3436: 3432: 3426: 3423: 3407: 3403: 3402: 3394: 3387: 3384: 3371: 3367: 3366: 3361: 3354: 3351: 3339: 3335: 3329: 3326: 3314: 3310: 3304: 3301: 3289: 3285: 3284: 3279: 3272: 3269: 3258:on 2016-09-28 3254: 3250: 3243: 3237: 3235: 3233: 3231: 3229: 3225: 3220: 3214: 3213:cite AV media 3207: 3206: 3192: 3188: 3187: 3179: 3176: 3164: 3160: 3156: 3149: 3146: 3134: 3130: 3129: 3124: 3117: 3115: 3111: 3099: 3095: 3091: 3084: 3081: 3068: 3064: 3060: 3053: 3050: 3037: 3033: 3029: 3022: 3019: 3006: 3002: 2998: 2991: 2988: 2973: 2969: 2962: 2955: 2952: 2949: 2945: 2942: 2937: 2934: 2930: 2924: 2921: 2917: 2911: 2908: 2902: 2899: 2894: 2890: 2886: 2882: 2878: 2874: 2867: 2864: 2859: 2855: 2851: 2847: 2840: 2837: 2832: 2828: 2824: 2820: 2816: 2812: 2805: 2802: 2797: 2793: 2786: 2783: 2778: 2774: 2770: 2763: 2760: 2755: 2751: 2745: 2742: 2730: 2726: 2720: 2717: 2713: 2708: 2705: 2701: 2697: 2694: 2689: 2686: 2682: 2677: 2674: 2670: 2665: 2662: 2658: 2646: 2642: 2638: 2632: 2629: 2617: 2613: 2609: 2603: 2600: 2589:on 2016-06-02 2585: 2578: 2572: 2569: 2558:on 2014-12-02 2557: 2553: 2551:9780691094809 2547: 2543: 2542: 2534: 2531: 2519: 2515: 2509: 2506: 2494: 2487: 2484: 2471: 2467: 2461: 2458: 2453: 2447: 2443: 2439: 2438: 2430: 2427: 2422: 2418: 2411: 2408: 2396: 2392: 2385: 2382: 2370: 2366: 2362: 2355: 2352: 2341: 2337: 2330: 2327: 2315: 2311: 2307: 2300: 2297: 2292: 2286: 2282: 2281: 2276: 2270: 2267: 2254: 2250: 2249: 2244: 2238: 2235: 2231: 2225: 2222: 2216: 2210: 2207: 2205: 2202: 2199: 2196: 2193: 2190: 2188: 2185: 2182: 2179: 2176: 2173: 2170: 2167: 2161: 2158: 2155: 2152: 2149: 2146: 2145: 2140: 2138: 2136: 2132: 2131:astrodynamics 2124: 2122: 2120: 2111: 2109: 2107: 2103: 2100:In addition, 2098: 2096: 2092: 2088: 2084: 2079: 2077: 2076:health threat 2073: 2069: 2065: 2061: 2053: 2051: 2049: 2045: 2041: 2037: 2032: 2029: 2022: 2018: 2017:Lunar Gateway 2014: 2010: 2003: 1998: 1991: 1989: 1987: 1982: 1980: 1976: 1972: 1968: 1967:petrochemical 1964: 1960: 1956: 1951: 1946:combinations. 1945: 1940: 1937: 1933: 1932: 1931: 1929: 1925: 1915: 1911: 1908: 1905: 1901: 1900: 1898: 1895: 1891: 1890:reaction mass 1887: 1883: 1880: 1877: 1873: 1869: 1866: 1865: 1864: 1861: 1859: 1855: 1849: 1847: 1838: 1833: 1828: 1820: 1818: 1816: 1808: 1800: 1796: 1792: 1788: 1784: 1776: 1768: 1764: 1760: 1755: 1753: 1749: 1744: 1742: 1737: 1733: 1729: 1721: 1719: 1716: 1713:operating on 1712: 1708: 1704: 1695: 1693: 1690: 1686: 1682: 1678: 1674: 1670: 1661: 1659: 1657: 1653: 1648: 1646: 1642: 1638: 1634: 1626: 1624: 1621: 1613: 1609: 1604: 1596: 1594: 1592: 1587: 1585: 1581: 1576: 1569: 1561: 1559: 1556: 1548: 1546: 1544: 1540: 1539:geostationary 1535: 1531: 1526: 1524: 1519: 1517: 1513: 1509: 1505: 1501: 1497: 1493: 1488: 1485: 1476: 1471: 1463: 1461: 1459: 1455: 1447: 1445: 1443: 1438: 1436: 1432: 1428: 1423: 1420: 1416: 1409: 1407: 1404: 1396: 1394: 1392: 1388: 1384: 1383:Earth/Moon L1 1380: 1372: 1368: 1364: 1360: 1355: 1353: 1349: 1345: 1341: 1337: 1334: 1330: 1329: 1324: 1320: 1315: 1313: 1308: 1307:reaction mass 1304: 1300: 1296: 1292: 1285: 1283: 1280: 1276: 1271: 1269: 1268:rocket engine 1265: 1261: 1260:rocket nozzle 1257: 1253: 1249: 1240: 1233: 1231: 1229: 1225: 1218: 1211: 1207: 1201: 1193: 1191: 1186: 1182: 1178: 1175: 1171: 1168: 1165: 1164: 1163: 1161: 1157: 1153: 1145: 1143: 1140: 1136: 1131: 1129: 1124: 1120: 1116: 1109: 1104: 1097: 1095: 1093: 1089: 1085: 1081: 1077: 1073: 1069: 1065: 1057: 1055: 1053: 1047: 1046:Oberth effect 1039: 1037: 1033: 1031: 1027: 1022: 1014: 1010: 1003: 998: 990: 985: 977: 975: 973: 969: 964: 961: 956: 952: 948: 939: 932: 930: 928: 923: 919: 917: 911: 905: 903: 901: 896: 894: 890: 886: 882: 878: 874: 870: 865: 862: 860: 856: 852: 848: 843: 841: 840:Mack Reynolds 837: 833: 829: 824: 821: 815: 812: 807: 805: 802:(the article 801: 797: 793: 786: 781: 774: 772: 770: 766: 762: 758: 754: 750: 746: 742: 738: 733: 731: 727: 725: 720: 716: 712: 708: 704: 699: 697: 693: 689: 688: 683: 682:25143 Itokawa 680: 676: 675: 670: 666: 662: 657: 655: 651: 650: 645: 641: 640: 635: 631: 630: 625: 621: 617: 613: 609: 603: 601: 600: 595: 594: 589: 588: 583: 582: 577: 576: 571: 567: 565: 560: 556: 555: 550: 546: 542: 534: 531:, as seen by 530: 525: 518: 516: 512: 508: 506: 502: 498: 494: 490: 486: 482: 479: 478:dwarf planets 475: 471: 467: 463: 459: 455: 451: 447: 443: 432: 427: 425: 420: 418: 413: 412: 410: 409: 406: 396: 395: 388: 385: 383: 380: 378: 375: 374: 368: 367: 360: 359:Intergalactic 357: 355: 352: 350: 347: 345: 342: 340: 337: 336: 330: 329: 322: 319: 317: 314: 312: 309: 305: 302: 300: 297: 295: 292: 291: 288: 283: 282: 269: 266: 264: 261: 259: 256: 254: 253:Space Shuttle 251: 249: 246: 244: 241: 239: 238: 235: 230: 229: 218: 215: 213: 210: 208: 205: 204: 201: 196: 195: 190: 185: 184: 177: 174: 172: 169: 167: 164: 162: 159: 157: 154: 152: 149: 147: 144: 142: 139: 137: 134: 133: 130: 125: 124: 117: 116:Mars missions 114: 112: 109: 107: 104: 102: 99: 97: 94: 92: 89: 88: 85: 80: 79: 73: 69: 68: 65: 61: 57: 53: 52: 43: 42: 19: 4861:Mars Society 4770:Solar System 4718:Terraforming 4687: 4532:Space launch 4517:Interstellar 4511: 4483:Destinations 4252:Apollo–Soyuz 4201:Space diving 4186:Space toilet 4010:Applications 3927:Soviet Union 3887:Space policy 3882:Space launch 3787: 3767:. 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