524:
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1997:
72:
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.
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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.
2009:
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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.
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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.
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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.
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
1023:
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
1346:(JIMO), originally planned for launch sometime in the next decade. Due to a shift in priorities at NASA that favored human crewed space missions, the project lost funding in 2005. A similar mission is currently under discussion as the US component of a joint NASA/ESA program for the exploration of
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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
1305:, which is then used to accelerate a chemically inert propellant to speeds far higher than achieved in a chemical rocket. Such drives produce feeble thrust, and are therefore unsuitable for quick maneuvers or for launching from the surface of a planet. But they are so economical in their use of
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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
33:
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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
763:, had as a long-term goal to eventually send human astronauts to Mars. However, on February 1, 2010, President Barack Obama proposed cancelling the program in Fiscal Year 2011. An earlier project which received some significant planning by NASA included a crewed fly-by of Venus in the
34:
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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;
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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
514:
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.
31:
1028:, which used slingshot effects to change trajectories several times in the outer Solar System. It is difficult to use this method for journeys in the inner part of the Solar System, although it is possible to use other nearby planets such as Venus or even the
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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
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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.
1666:
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
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
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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
1912:
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
1843:
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
922:
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
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
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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.
1270:. Due to the low molecular mass and hence high thermal velocity of hydrogen these engines are at least twice as fuel efficient as chemical engines, even after including the weight of the reactor.
867:
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
1896:(thrust per kilogram of reaction mass), but it has been claimed that water will beat hydrogen in cost/performance terms despite its much lower specific impulse by orders of magnitude.
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925:
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.
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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:
1582:, and the most ambitious schemes aim to balance loads going up and down and thus make the energy cost close to zero. Space elevators have also sometimes been referred to as "
1422:
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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1926:'s crust, and is probably abundant in most other bodies in the Solar System. Non-terrestrial oxygen would be valuable as a source of water ice only if an adequate source of
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3132:
1007:
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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2714:
C. R. Williams et al., 'Realizing "2001: A Space
Odyssey": Piloted Spherical Torus Nuclear Fusion Propulsion', 2001, 52 pages, NASA Glenn Research Center
1331:, the first NASA operational (i.e., non-technology demonstration) mission to use an ion drive for its primary propulsion, successfully orbited the large
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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.
1325:, which fired for a total of 678 days and enabled the probe to run down Comet Borrelly, a feat which would have been impossible for a chemical rocket.
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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
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are rather sooty and therefore very hard to detect. Although carbonaceous chondrites are thought to be rare, some are very large and the suspected "
864:
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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3004:
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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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2078:. Even the minimum levels of radiation during these fluctuations is comparable to the current annual limit for astronauts in low-Earth orbit.
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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.
1361:, has as of January 2011 described "Nautilus-X", a concept study for a multi-mission space exploration vehicle useful for missions beyond
381:
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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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17:
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1377:) designs, nuclear ion-electric drive is shown for illustrative purposes. It is intended for integration and checkout at the
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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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1074:
have made it possible to exploit many more features of the gravity fields of astronomical bodies and thus calculate even
992:
Simplified example of a gravitational slingshot: the spacecraft's velocity changes by up to twice the planet's velocity.
941:
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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667:, and was even successfully landed there, though it had not been designed with this maneuver in mind. The Japanese
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spacecraft have landed on the surface of Venus, with the latter deploying balloons to the planet's atmosphere. The
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2070:. Beyond the Van Allen belts, radiation levels generally decrease, but can fluctuate over time. These high energy
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3312:
2203:
1208:, which sets the characteristic velocity available as a function of exhaust velocity and mass ratio, of initial (
1054:). The use at this point multiplies up the effect of the delta-v, and gives a bigger effect than at other times.
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1460:, the barriers to fast interplanetary travel involve engineering and economics rather than any basic physics.
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It is possible to put stations or spacecraft on orbits that cycle between different planets, for example a
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684:, landing on it briefly and returning grains of its surface material to Earth. Another ion-drive mission,
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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
1378:
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L. Johnson, B. Gilchrist, R. D. Estes, and E. Lorenzini, "Overview of future NASA tether applications,"
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1671:. One alternative to transport more mass on interplanetary trajectories is to use up nearly all of the
1342:. A more ambitious, nuclear-powered version was intended for a Jupiter mission without human crew, the
902:, argue that the vast majority of mankind eventually will live in space and will benefit from doing so.
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491:. Orbiters and landers return more information than fly-by missions. Crewed flights have landed on the
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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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1381:(ISS), and would be suitable for deep-space missions from the ISS to and beyond the Moon, including
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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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476:. Uncrewed space probes have flown to all the observed planets in the Solar System as well as to
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100:
3462:"The Cosmic Ray Radiation Dose in Interplanetary Space – Present Day and Worst-Case Evaluations"
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3393:"NASA's Efforts to Manage Health and Human Performance Risks for Space Exploration (IG-16-003)"
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1433:. It achieves characteristic velocities of >300 km/s with an acceleration of ~1.7•10
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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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2012:
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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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1892:. Hydrogen has also been proposed for use in these engines and would provide much greater
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4195:
4091:
3943:
3690:
2888:
2336:"Americans' Views of Space: U.S. Role, NASA Priorities and Impact of Private Companies"
2067:
2001:
1958:
1782:
1740:
1680:
1528:
Currently, the only spacecraft to use a solar sail as the main method of propulsion is
1483:
1332:
764:
404:
199:
165:
155:
3669:
3618:
3557:
3059:"Space Elevators On Hold At Least Until Stronger Materials Are Available, Experts Say"
2941:
Hypersonic Airplane Space Tether Orbital Launch (HASTOL) System: Interim Study Results
2607:
1440:
Fusion rockets are considered to be a likely source of interplanetary transport for a
830:
writers have a fairly good track record in predicting future technologies—for example
4627:
4586:
4226:
4121:
4096:
4042:
4032:
3849:
3791:
3622:
3561:
3518:
2940:
2892:
2668:
2545:
2445:
2391:"Myth-free space advocacy part I--The myth of innate exploratory and migratory urges"
2284:
2168:
2043:
1943:
1863:
Water ice would be very useful and is widespread on the moons of Jupiter and Saturn:
1794:
1688:
1619:
1498:". More recent light sail designs propose to boost the thrust by aiming ground-based
1390:
1327:
1266:. The energy replaces the chemical energy of the reactive chemicals in a traditional
686:
653:
562:
449:
233:
145:
3309:"Origin of How Steam Rockets can Reduce Space Transport Cost by Orders of Magnitude"
2555:
1996:
1226:(mass of payload and rocket without fuel) falls to below 10% of the entire rocket's
4818:
4712:
4499:
4328:
4285:
4251:
4216:
4153:
4106:
3948:
3614:
3553:
2880:
2826:
2229:
1954:
1893:
1751:
1684:
1491:
1426:
1386:
1382:
1370:
1166:
892:
868:
835:
643:
544:
504:
465:
267:
216:
71:
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
4794:
4544:
4444:
4397:
4295:
4236:
4221:
4175:
4158:
4064:
4059:
3746:
3585:
2947:
2699:
2278:
2174:
2059:
1726:
As an example of a funded project currently under development, a key part of the
1706:
1702:
1676:
1668:
1632:
1437:, with a ship initial mass of ~1700 metric tons, and payload fraction above 10%.
1362:
1351:
1294:
1184:
1107:
1079:
1025:
971:
949:. Hohmann demonstrated that the lowest energy route between any two orbits is an
872:
827:
706:
638:
315:
170:
4748:
4591:
4578:
4471:
4402:
4392:
4377:
4355:
4345:
4241:
4231:
4180:
4101:
2725:"The Physics of Interstellar Travel : Official Website of Dr. Michio Kaku"
2197:
1786:
1762:
1747:
1735:
1583:
1574:
1567:
1418:
1402:
1311:
1134:
1122:
854:
756:
740:
702:
660:
310:
3184:
2228:
Interplanetary Flight: an introduction to astronautics. London: Temple Press,
2133:
reasons, economic spacecraft travel to other planets is only practical within
1909:
The water would provide some additional protection against ionizing radiation;
1607:
4895:
4539:
4456:
4387:
4350:
4190:
4111:
3975:
3970:
2492:
2134:
2130:
2121:
mission survived despite an explosion caused by a faulty oxygen tank (1970).
2016:
1966:
1889:
1766:
1579:
1538:
1414:
1347:
1306:
1267:
1045:
1008:
839:
681:
257:
252:
247:
175:
150:
1490:
The original concept relied only on radiation from the Sun – for example in
1238:
809:
Many astronomers, geologists and biologists believe that exploration of the
4860:
4717:
4596:
4531:
4200:
4185:
3886:
3881:
3626:
3565:
3522:
3282:
2809:
Edwards, Bradley C. (2004). "A Space Elevator Based Exploration Strategy".
1985:
1871:
1790:
1644:
1542:
1525:, there have been several proposals for their use within the Solar System.
1318:
1155:
810:
795:
729:
718:
598:
553:
477:
473:
286:
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
988:
937:
914:
than the planet to which the spacecraft is travelling (in accordance with
4424:
4290:
3980:
3963:
3835:
3278:"Elon Musk scales up his ambitions, considering going "well beyond" Mars"
2274:
2071:
1903:
1672:
1586:", "space bridges", "space lifts", "space ladders" and "orbital towers".
1554:
1357:
A NASA multi-center Technology Applications Assessment Team led from the
1302:
1114:
540:
469:
211:
63:
3090:"60,000 miles up: Space elevator could be built by 2035, says new study"
1831:
1066:
were first proposed (1925) and were slow, expensive and unreliable when
4558:
4466:
4409:
4369:
4163:
3864:
2884:
2008:
1991:
1978:
1853:
1714:
1469:
1366:
1298:
1138:
880:
592:
586:
298:
262:
188:
95:
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
1127:
4642:
4568:
4419:
4136:
4017:
3938:
3921:
2243:"NASA Spacecraft Embarks on Historic Journey Into Interstellar Space"
2118:
2090:
1651:
1495:
1322:
1159:
1087:
1071:
1051:
735:
No crewed missions have been sent to any planet of the Solar System.
668:
648:
619:
580:
574:
293:
206:
40:
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
1927:
1640:
1278:
1255:
1227:
1223:
959:
858:
846:
799:
664:
652:, March 2011), and have returned data about these bodies and their
611:
543:
have flown by all of the observed planets of the Solar System from
488:
2870:
1902:
The water would absorb and conduct solar energy, thus acting as a
3364:
2147:
1974:
1970:
1962:
1806:
1474:
1339:
1335:
1162:. These improved technologies typically focus on one or more of:
1020:
954:
950:
926:
791:
691:
623:
548:
461:
3535:
2683:
NASA/JSC Multi-Mission Space Exploration Vehicle, Jan. 26, 2011.
1750:
as more equipment arrives, is installed, and placed into mostly-
1635:
is designed to be fully and rapidly reusable, making use of the
945:
For many years economical interplanetary travel meant using the
779:
518:
4875:
4382:
4246:
3248:
3236:
3234:
3232:
3230:
3228:
2280:
The End of Astronauts: Why Robots Are the Future of Exploration
2086:
1798:
1727:
1529:
1263:
1259:
714:
633:
472:
of this type are confined to travel between the planets of the
3804:
3509:
Siniak IuE, Turusov VS; Grigorev, AI; et al. (2003). "".
2183: – Hypothetical travel between stars or planetary systems
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,
1836:
1683:
trajectory. These propellants could be stored on orbit at a
1623:
engineeringly feasible using presently available materials".
1511:
1507:
1503:
1499:
748:
607:
558:
528:
500:
480:
457:
3596:
3334:""Neofuel" -interplanetary travel using off-earth resources"
3225:
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
1626:
1233:
1121:
of the target planet to slow down. It was first used on the
1110:
to aerobrake by skimming the atmosphere (artistic rendition)
1102:
4865:
3400:
3176:
2062:
and the protection of Earth's magnetosphere, it enters the
1923:
1731:
1533:
1180:
1029:
744:
736:
615:
496:
492:
3333:
2927:
E. M. Levin, "Dynamic Analysis of Space Tether Missions",
1145:
771:
was terminated due to NASA budget cuts in the late 1960s.
4263:
2844:
Moravec, H. (1977). "A non-synchronous orbital skyhook".
2693:"NASA Team Produces NAUTILUS-X, A Fascinating Spacecraft"
2105:
1774:
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"
2958:
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
1721:
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
774:
1938:
of space ships, space stations and planetary bases.
1820:
3508:
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"
4893:
3384:
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:
2358:
1846:Non-terrestrial sources of energy and materials
1019:The gravitational slingshot technique uses the
905:
713:have landed on the surface of Mars and several
3081:
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).
2273:
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:
3111:
3050:
3019:
2792:"The Space Elevator Comes Closer to Reality"
2766:
2333:
2211: – Method used to accelerate spacecraft
1977:could be a valuable feedstock for producing
1695:
1078:. Paths have been calculated which link the
875:like the one which may have resulted in the
70:
3351:
3269:
3146:
2952:
2750:"Abstracts of NASA articles on solar sails"
2458:
2306:"The Scientific Case for Human Spaceflight"
1789:will process the raw materials by means of
1193:
853:(unhampered by clouds) and the very strong
838:) and many aspects of computer technology (
4665:
4651:
3827:
3813:
2490:
2437:Orbital Mechanics for Engineering Students
1953:Scientists expect to find a vast range of
1396:
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
977:
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:
3785:
3152:
3087:
2427:
2414:
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.
2537:
2388:
2303:
2007:
1995:
1830:
1658:over what NASA had previously achieved.
1639:that was developed during 2011–2018 for
1606:
1473:
1314:missions took 3 days in each direction.
1237:
1101:
995:
987:
936:
832:geosynchronous communications satellites
778:
522:
44:as it flies by Earth en route to Mercury
26:
4312:Effect of spaceflight on the human body
3459:
3025:
2994:
2988:
2843:
2808:
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
14:
4894:
4672:
4334:Psychological and sociological effects
3760:"Launch Windows: Timing is Everything"
3275:
3186:Making Humans a Multiplanetary Species
3153:Belluscio, Alejandro G. (2014-03-07).
3120:
3056:
2934:
2918:, vol. 24, no. 8, pp. 1055–1063, 1999.
2433:
1930:can be found. Possible uses include:
1922:Oxygen is a common constituent of the
1661:
1285:
1151:
1133:Aerobraking converts the spacecraft's
1130:is only about 1% as thick as Earth's.
728:successfully landed on Saturn's moon,
4646:
3808:
3390:
3372:from the original on January 30, 2019
2846:Journal of the Astronautical Sciences
2789:
2359:Aldrin, Buzz; Wachhorst, Wyn (2004).
877:Cretaceous–Paleogene extinction event
818:least as useful in other activities (
3357:
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
1447:
1158:mission was a successful test of an
1142:material available near the target.
1039:
932:
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.
3757:
3469:International Cosmic Ray Conference
3007:from the original on 10 August 2014
1541:communications satellites built by
24:
4043:Weather and environment monitoring
3779:
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:
4918:
3490:from the original on 4 March 2016
3358:Dunn, Marcia (October 29, 2015).
3069:from the original on 2 March 2014
2124:
1561:
1409:
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
3834:
3751:
3733:
3722:from the original on 2016-03-08
3716:"yarchive.net/space/spacecraft"
3708:
3697:from the original on 2016-12-18
3683:
3658:
3647:from the original on 2010-08-21
3633:
3590:
3572:
3529:
3502:
3453:
3437:. 18 March 2015. Archived from
3423:
3340:from the original on 2006-11-16
3326:
3315:from the original on 2017-11-16
3301:
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
2921:
2908:
2899:
2864:
2837:
2802:
2783:
2769:"Buzz Aldrin's Roadmap To Mars"
2760:
2742:
2731:from the original on 2019-07-08
2717:
2705:
2686:
2674:
2662:
2647:from the original on 2024-02-07
2629:
2618:from the original on 2017-11-17
2600:
2569:
2531:
2520:from the original on 2019-10-22
2506:
2484:
2316:from the original on 2019-04-06
2204:Space travel in science fiction
2022:
1057:
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.
2408:
2382:
2352:
2327:
2297:
2267:
2235:
2222:
2187:List of interplanetary voyages
2160:Health threat from cosmic rays
2111:
1463:
1097:
885:asteroid deflection strategies
13:
1:
3619:10.1016/S1350-4487(99)00063-3
3558:10.1016/S0094-5765(02)00013-9
2767:Aldrin, B; Noland, D (2005).
2216:
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).
2053:
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
7:
4440:Self-replicating spacecraft
4276:International Space Station
3666:"islandone.org/Settlements"
3276:Berger, Eric (2016-09-18).
2794:. space.com. Archived from
2140:
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
10:
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:
1596:
1565:
1548:
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
4853:
4827:
4757:
4726:
4680:
4610:
4577:
4530:
4482:
4368:
4317:Space adaptation syndrome
4304:
4209:
4129:
4120:
4008:
3842:
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
18:Interplanetary spacecraft
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:
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:
4643:
4630:
4619:
4618:
4329:Space psychology
4154:Animals in space
4127:
4126:
4107:Space technology
3949:Rescue Agreement
3829:
3822:
3815:
3806:
3805:
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:. Archived from
3662:
3656:
3655:
3653:
3652:
3637:
3631:
3630:
3594:
3588:
3576:
3570:
3569:
3533:
3527:
3526:
3506:
3500:
3499:
3497:
3495:
3489:
3466:
3460:Mewaldt (2005).
3457:
3451:
3450:
3448:
3446:
3427:
3421:
3420:
3418:
3416:
3410:
3404:. Archived from
3397:
3388:
3382:
3381:
3379:
3377:
3355:
3349:
3348:
3346:
3345:
3330:
3324:
3323:
3321:
3320:
3305:
3299:
3298:
3296:
3295:
3273:
3267:
3266:
3264:
3263:
3257:
3246:
3238:
3223:
3222:
3216:
3208:
3200:
3198:
3180:
3174:
3173:
3171:
3170:
3150:
3144:
3143:
3141:
3140:
3118:
3109:
3108:
3106:
3105:
3085:
3079:
3078:
3076:
3074:
3054:
3048:
3047:
3045:
3043:
3023:
3017:
3016:
3014:
3012:
2992:
2986:
2985:
2983:
2982:
2976:
2965:
2956:
2950:
2938:
2932:
2925:
2919:
2912:
2906:
2903:
2897:
2896:
2868:
2862:
2861:
2841:
2835:
2834:
2806:
2800:
2799:
2787:
2781:
2780:
2775:. Archived from
2764:
2758:
2757:
2752:. 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:
227:
217:Cargo spacecraft
194:
193:
51:
50:
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:
3782:
3780:Further reading
3777:
3768:
3766:
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:
3595:
3591:
3586:Wayback Machine
3577:
3573:
3534:
3530:
3507:
3503:
3493:
3491:
3487:
3464:
3458:
3454:
3444:
3442:
3429:
3428:
3424:
3414:
3412:
3408:
3395:
3389:
3385:
3375:
3373:
3356:
3352:
3343:
3341:
3332:
3331:
3327:
3318:
3316:
3307:
3306:
3302:
3293:
3291:
3274:
3270:
3261:
3259:
3255:
3244:
3240:
3239:
3226:
3210:
3209:
3196:
3194:
3182:
3181:
3177:
3168:
3166:
3151:
3147:
3138:
3136:
3119:
3112:
3103:
3101:
3086:
3082:
3072:
3070:
3063:Huffington Post
3055:
3051:
3041:
3039:
3024:
3020:
3010:
3008:
2993:
2989:
2980:
2978:
2974:
2963:
2957:
2953:
2948:Wayback Machine
2939:
2935:
2926:
2922:
2913:
2909:
2904:
2900:
2869:
2865:
2842:
2838:
2807:
2803:
2788:
2784:
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:
2536:
2532:
2523:
2521:
2514:"Gravity's Rim"
2512:
2511:
2507:
2498:
2496:
2495:. .jpl.nasa.gov
2489:
2485:
2475:
2473:
2472:on July 1, 2007
2464:
2463:
2459:
2452:
2432:
2428:
2413:
2409:
2400:
2398:
2387:
2383:
2374:
2372:
2357:
2353:
2344:
2342:
2332:
2328:
2319:
2317:
2302:
2298:
2291:
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:
4910:
4909:
4904:
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:
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:
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:
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:
3765:
3761:
3754:
3748:
3744:
3741:
3736:
3721:
3717:
3711:
3696:
3692:
3686:
3672:on 2016-04-05
3671:
3667:
3661:
3646:
3642:
3636:
3628:
3624:
3620:
3616:
3612:
3608:
3604:
3600:
3593:
3587:
3583:
3580:
3575:
3567:
3563:
3559:
3555:
3551:
3547:
3544:(7): 575–80.
3543:
3539:
3532:
3524:
3520:
3516:
3512:
3505:
3486:
3482:
3478:
3474:
3470:
3463:
3456:
3440:
3436:
3432:
3426:
3407:
3403:
3402:
3394:
3387:
3371:
3367:
3366:
3361:
3354:
3339:
3335:
3329:
3314:
3310:
3304:
3289:
3285:
3284:
3279:
3272:
3258:on 2016-09-28
3254:
3250:
3243:
3237:
3235:
3233:
3231:
3229:
3220:
3214:
3213:cite AV media
3207:
3206:
3192:
3188:
3187:
3179:
3164:
3160:
3156:
3149:
3134:
3130:
3129:
3124:
3117:
3115:
3099:
3095:
3091:
3084:
3068:
3064:
3060:
3053:
3037:
3033:
3029:
3022:
3006:
3002:
2998:
2991:
2973:
2969:
2962:
2955:
2949:
2945:
2942:
2937:
2930:
2924:
2917:
2911:
2902:
2894:
2890:
2886:
2882:
2878:
2874:
2867:
2859:
2855:
2851:
2847:
2840:
2832:
2828:
2824:
2820:
2816:
2812:
2805:
2797:
2793:
2786:
2778:
2774:
2770:
2763:
2755:
2751:
2745:
2730:
2726:
2720:
2713:
2708:
2701:
2697:
2694:
2689:
2682:
2677:
2670:
2665:
2658:
2646:
2642:
2638:
2632:
2617:
2613:
2609:
2603:
2589:on 2016-06-02
2585:
2578:
2572:
2558:on 2014-12-02
2557:
2553:
2551:9780691094809
2547:
2543:
2542:
2534:
2519:
2515:
2509:
2494:
2487:
2471:
2467:
2461:
2453:
2447:
2443:
2439:
2438:
2430:
2422:
2418:
2411:
2396:
2392:
2385:
2370:
2366:
2362:
2355:
2341:
2337:
2330:
2315:
2311:
2307:
2300:
2292:
2286:
2282:
2281:
2276:
2270:
2254:
2250:
2249:
2244:
2238:
2231:
2225:
2221:
2210:
2207:
2205:
2202:
2199:
2196:
2193:
2190:
2188:
2185:
2182:
2179:
2176:
2173:
2170:
2167:
2161:
2158:
2155:
2152:
2149:
2146:
2145:
2138:
2136:
2132:
2131:astrodynamics
2122:
2120:
2109:
2107:
2103:
2100:In addition,
2098:
2096:
2092:
2088:
2084:
2079:
2077:
2076:health threat
2073:
2069:
2065:
2061:
2051:
2049:
2045:
2041:
2037:
2032:
2029:
2018:
2017:Lunar Gateway
2014:
2010:
2003:
1998:
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:
1818:
1816:
1808:
1800:
1796:
1792:
1788:
1784:
1776:
1768:
1764:
1760:
1755:
1753:
1749:
1744:
1742:
1737:
1733:
1729:
1719:
1716:
1713:operating on
1712:
1708:
1704:
1693:
1690:
1686:
1682:
1678:
1674:
1670:
1659:
1657:
1653:
1648:
1646:
1642:
1638:
1634:
1624:
1621:
1613:
1609:
1604:
1594:
1592:
1587:
1585:
1581:
1576:
1569:
1559:
1556:
1546:
1544:
1540:
1539:geostationary
1535:
1531:
1526:
1524:
1519:
1517:
1513:
1509:
1505:
1501:
1497:
1493:
1488:
1485:
1476:
1471:
1461:
1459:
1455:
1445:
1443:
1438:
1436:
1432:
1428:
1423:
1420:
1416:
1407:
1404:
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:
1283:
1280:
1276:
1271:
1269:
1268:rocket engine
1265:
1261:
1260:rocket nozzle
1257:
1253:
1249:
1240:
1231:
1229:
1225:
1218:
1211:
1207:
1201:
1191:
1186:
1182:
1178:
1175:
1171:
1168:
1165:
1164:
1163:
1161:
1157:
1153:
1143:
1140:
1136:
1131:
1129:
1124:
1120:
1116:
1109:
1104:
1095:
1093:
1089:
1085:
1081:
1077:
1073:
1069:
1065:
1055:
1053:
1047:
1046:Oberth effect
1037:
1033:
1031:
1027:
1022:
1014:
1010:
1003:
998:
990:
985:
975:
973:
969:
964:
961:
956:
952:
948:
939:
930:
928:
923:
919:
917:
911:
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:
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:
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:
62:
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:. Retrieved
3763:
3753:
3735:
3724:. Retrieved
3710:
3699:. Retrieved
3685:
3674:. Retrieved
3670:the original
3660:
3649:. Retrieved
3635:
3602:
3598:
3592:
3574:
3541:
3537:
3531:
3514:
3510:
3504:
3492:. Retrieved
3472:
3468:
3455:
3443:. Retrieved
3439:the original
3434:
3425:
3413:. Retrieved
3406:the original
3399:
3386:
3374:. Retrieved
3363:
3353:
3342:. Retrieved
3328:
3317:. Retrieved
3303:
3292:. Retrieved
3283:Ars Technica
3281:
3271:
3260:. Retrieved
3253:the original
3203:
3202:
3195:. Retrieved
3185:
3178:
3167:. Retrieved
3158:
3148:
3137:. Retrieved
3126:
3102:. Retrieved
3094:Extreme Tech
3093:
3083:
3071:. Retrieved
3062:
3052:
3040:. Retrieved
3031:
3021:
3009:. Retrieved
3000:
2990:
2979:. Retrieved
2967:
2954:
2936:
2928:
2923:
2915:
2910:
2901:
2876:
2872:
2866:
2849:
2845:
2839:
2814:
2810:
2804:
2796:the original
2785:
2777:the original
2772:
2762:
2754:the original
2744:
2733:. Retrieved
2719:
2707:
2688:
2676:
2664:
2655:
2649:. Retrieved
2640:
2631:
2620:. Retrieved
2611:
2602:
2591:. Retrieved
2584:the original
2571:
2560:. Retrieved
2556:the original
2540:
2533:
2522:. Retrieved
2508:
2497:. Retrieved
2486:
2474:. Retrieved
2470:the original
2460:
2436:
2429:
2421:the original
2410:
2399:. Retrieved
2394:
2384:
2373:. Retrieved
2368:
2364:
2354:
2343:. Retrieved
2339:
2329:
2318:. Retrieved
2309:
2299:
2279:
2275:Rees, Martin
2269:
2257:. Retrieved
2246:
2237:
2224:
2128:
2115:
2099:
2080:
2057:
2033:
2026:
2023:Life support
1986:mass drivers
1983:
1952:
1949:
1921:
1862:
1850:
1842:
1813:), and then
1791:electrolysis
1756:
1745:
1725:
1699:
1681:heliocentric
1665:
1649:
1645:Falcon Heavy
1630:
1617:
1588:
1571:
1552:
1543:EADS Astrium
1527:
1520:
1515:
1489:
1481:
1451:
1439:
1434:
1424:
1413:
1400:
1387:Sun/Earth L2
1356:
1326:
1316:
1301:to generate
1289:
1272:
1245:
1216:
1209:
1203:
1189:
1156:Deep Space 1
1149:
1132:
1113:
1061:
1058:Fuzzy orbits
1049:
1034:
1018:
1012:
1001:
965:
944:
924:
920:
912:
909:
897:
866:
863:
851:solar panels
844:
825:
816:
811:Solar System
808:
796:Deep Space 2
789:
734:
723:
709:and the two
700:
685:
672:
658:
647:
637:
627:
604:
599:New Horizons
597:
591:
585:
579:
573:
563:
554:New Horizons
552:
541:space probes
538:
533:New Horizons
532:
513:
509:
474:Solar System
470:spaceflights
445:
441:
440:
382:Space forces
354:Interstellar
348:
287:Space launch
129:Applications
106:Space probes
39:
4734:Bishop Ring
4490:Sub-orbital
4425:Space probe
4291:New Shepard
4269:Shuttle–Mir
4028:Archaeology
3981:Space force
3964:Moon Treaty
3836:Spaceflight
3517:(6): 60–3.
3475:(29): 433.
3415:October 29,
3376:October 30,
2879:(1): 3–20.
2817:: 854–862.
2371:(11): 37–38
2259:20 February
2112:Reliability
2072:cosmic rays
2042:related to
1979:fertilizers
1904:heat shield
1872:electrolyse
1854:solar cells
1797:to produce
1673:upper stage
1650:SpaceX CEO
1555:Mars cycler
1464:Solar sails
1303:electricity
1299:solar cells
1115:Aerobraking
1098:Aerobraking
1088:commodities
671:spacecraft
551:, with the
339:Sub-orbital
263:Spaceplanes
212:Space probe
146:Exploration
64:Spaceflight
4896:Categories
4819:Free space
4559:Launch pad
4550:Expendable
4500:Geocentric
4467:Solar sail
4410:Spaceplane
4370:Spacecraft
4164:Space suit
4142:commercial
4070:Television
3865:Space Race
3769:2024-06-16
3726:2007-05-20
3701:2007-05-20
3676:2007-05-20
3651:2007-05-20
3494:19 October
3445:19 October
3344:2006-10-08
3319:2007-02-16
3294:2016-09-19
3262:2016-09-29
3197:10 October
3169:2014-03-07
3139:2016-09-27
3104:2014-04-19
2981:2014-03-20
2735:2021-09-27
2681:NAUTILUS-X
2669:Nautilus-X
2651:2024-02-07
2622:2018-09-12
2593:2016-05-13
2577:"NASA.gov"
2562:2007-04-07
2524:2023-04-12
2499:2016-06-26
2401:2024-06-22
2375:2024-06-22
2345:2024-06-22
2320:2007-04-07
2217:References
2093:(a stable
1783:atmosphere
1584:beanstalks
1516:decelerate
1470:Solar sail
1367:Nautilus-X
1262:to create
1139:heatshield
1119:atmosphere
951:elliptical
881:Spaceguard
707:Pathfinder
593:Pioneer 11
587:Pioneer 10
566:spacecraft
304:Expendable
299:Launch pad
189:Spacecraft
171:Telescopes
166:Settlement
161:Navigation
96:Space Race
38:View from
4790:Asteroids
4569:Spaceport
4420:Satellite
4137:Astronaut
4065:Telephone
4018:Astronomy
3939:Space law
3892:Australia
3073:13 August
3042:13 August
3011:13 August
2893:123134965
2873:Meccanica
2397:: 450–460
2312:: 14–17.
2119:Apollo 13
2104:from the
2091:deuterium
2068:radiation
2054:Radiation
2038:issued a
1781:from the
1718:journey.
1715:densified
1652:Elon Musk
1496:Sunjammer
1323:ion drive
1160:ion drive
1117:uses the
1072:computing
1052:periapsis
1013:Voyager 2
1002:Voyager 2
847:asteroids
669:ion-drive
649:MESSENGER
632:, 1995),
622:, 1971),
620:Mariner 9
614:, 1970),
581:Voyager 2
575:Voyager 1
489:asteroids
387:Companies
294:Spaceport
207:Satellite
151:Espionage
41:MESSENGER
4621:Category
4286:Tiangong
4281:Shenzhou
4210:Programs
4055:Internet
3860:Timeline
3743:Archived
3720:Archived
3695:Archived
3645:Archived
3627:11543148
3582:Archived
3566:12575722
3523:14959623
3485:Archived
3370:Archived
3338:Archived
3313:Archived
3288:Archived
3191:Archived
3163:Archived
3133:Archived
3098:Archived
3067:Archived
3036:Archived
3005:Archived
2972:Archived
2944:Archived
2729:Archived
2696:Archived
2657:chamber.
2645:Archived
2641:X-Energy
2616:Archived
2518:Archived
2314:Archived
2253:Archived
2141:See also
1971:plastics
1928:hydrogen
1878:engines.
1793:and the
1641:Falcon 9
1452:See the
1352:Ganymede
1279:Saturn V
1256:hydrogen
1228:wet mass
1224:dry mass
1000:Plot of
960:aphelion
859:peak oil
800:Beagle 2
674:Hayabusa
665:433 Eros
612:Venera 7
561:and the
454:uncrewed
308:reusable
156:Military
56:a series
54:Part of
4775:Mercury
4495:Orbital
4296:Artemis
4227:Voskhod
4222:Mercury
4130:General
3870:Records
3855:History
3843:General
3607:Bibcode
3546:Bibcode
3477:Bibcode
3365:AP News
3001:io9.com
2854:Bibcode
2819:Bibcode
2476:June 1,
2148:Delta-v
2074:pose a
1975:ammonia
1963:methane
1934:In the
1815:liquefy
1807:methane
1597:Skyhook
1549:Cyclers
1340:4 Vesta
1336:1 Ceres
1317:NASA's
1273:The US
1021:gravity
955:tangent
927:delta-v
792:Mars 96
724:Huygens
644:Mercury
629:Galileo
624:Jupiter
549:Neptune
545:Mercury
505:Mercury
462:planets
448:is the
344:Orbital
176:Tourism
84:History
4876:SpaceX
4845:Europa
4795:mining
4632:Portal
4625:
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4383:Rocket
4247:Skylab
4242:Apollo
4232:Gemini
4217:Vostok
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2087:cancer
1973:. And
1805:) and
1799:oxygen
1748:synods
1728:system
1679:for a
1530:IKAROS
1512:masers
1508:lasers
1504:masers
1500:lasers
1348:Europa
1312:Apollo
1264:thrust
1009:Triton
798:, and
715:Venera
703:Viking
634:Saturn
596:, and
450:crewed
268:Vostok
4840:Venus
4807:Titan
4780:Venus
4435:Rover
4237:Soyuz
4060:Radio
3917:Japan
3912:India
3897:China
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1837:igloo
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730:Titan
726:probe
696:Ceres
692:Vesta
608:Venus
570:Ceres
559:Pluto
529:Pluto
501:Venus
485:Ceres
481:Pluto
458:stars
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4835:Mars
4802:Moon
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3623:PMID
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3496:2021
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3435:NASA
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3401:NASA
3378:2015
3219:link
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3075:2014
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3013:2014
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1765:and
1757:The
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1643:and
1631:The
1534:JAXA
1350:and
1338:and
1328:Dawn
1181:cost
1030:Moon
820:NASA
745:Moon
737:NASA
719:Vega
717:and
687:Dawn
659:The
616:Mars
578:and
564:Dawn
503:and
497:Mars
493:Moon
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