Future of space exploration
The future of space exploration involves both telescopic exploration and the physical exploration of space by robotic spacecraft and human spaceflight.
Near-term physical exploration missions, focused on obtaining new information about the solar system, are planned and announced by both national and private organisations. There are tentative plans for crewed orbital and landing missions to the Moon and Mars to establish scientific outposts that will later enable permanent and self-sufficient settlements. Further exploration will potentially involve expeditions and settlements on the other planets and their moons as well as establishing mining and fueling outposts, particularly in the asteroid belt. Physical exploration outside the solar system will be robotic for the foreseeable future.
Uncrewed missions
Breakthrough Starshot
Breakthrough Starshot is a research and engineering project by the Breakthrough Initiatives to develop a proof-of-concept fleet of light sail spacecraft named StarChip,[1] to be capable of making the journey to the Alpha Centauri star system 4.37 light-years away. It was founded in 2016 by Yuri Milner, Stephen Hawking, and Mark Zuckerberg.[2][3]
Moon
Chang'e 5
Chang'e 5 is a robotic Chinese lunar exploration mission consisting of a lander and a sample-return vehicle. It is scheduled for launch in 2020,[4][5] after being postponed due to the failure of the second Long March 5 launch vehicle in 2017.[6] Chang'e 5 will be China's first sample return mission, aiming to return at least 2 kilograms of lunar soil and rock samples back to the Earth.[7] Like its predecessors, the spacecraft is named after the Chinese Moon goddess, Chang'e.
This will be the first lunar sample-return mission since Luna 24 in 1976 and - if successful - it would make China the third country to return samples from the Moon. It will launch from the Wenchang Satellite launch centre in Hainan.
SLIM
Smart Lander for Investigating Moon (SLIM) is a lunar lander being developed by the Japan Aerospace Exploration Agency (JAXA). The lander will demonstrate precision landing technology.[8] By 2017, the lander was to be launched in 2021,[9][10] but this has been subsequently delayed to January 2022 due to delays in SLIM's rideshare mission, XRISM.[11]
Artemis 1
Artemis 1[12] is an upcoming uncrewed flight test for NASA's Artemis program that is the first integrated flight of the agency's Orion MPCV and Space Launch System heavy-lift rocket.
Formerly known as Exploration Mission-1 (EM-1), the mission was renamed after the introduction of the Artemis program. The launch will be held at Launch Complex 39B at the Kennedy Space Center, where an Orion spacecraft will be sent on a mission of 25.5 days, 6 of those days in a retrograde orbit around the Moon.[13] The mission will certify the Orion spacecraft and Space Launch System rocket for crewed flights beginning with the second flight test of the Orion and Space Launch System, Artemis 2 in September 2022, which will carry a crew of four around the Moon in a week-long mission and back prior to the assembly of the Lunar Gateway in lunar orbit, which will occur between 2022 and 2023.
Mars
Rosalind Franklin
Rosalind Franklin,[14] previously known as the ExoMars rover, is a planned robotic Mars rover, part of the international ExoMars programme led by the European Space Agency and the Russian Roscosmos State Corporation.[15][16]
Initially scheduled to launch in July 2020, but has since been delayed due to testing issues with the rover’s landing mechanism. The new launch date is set for July 2022.[17] the plan calls for a Russian launch vehicle, an ESA carrier module, and a Russian lander named Kazachok,[18] that will deploy the rover to Mars' surface.[19] Once safely landed, the solar powered rover will begin a seven-month (218-sol) mission to search for the existence of past life on Mars. The Trace Gas Orbiter (TGO), launched in 2016, will operate as Rosalind Franklin's and lander's data-relay satellite.[20]
Mars 2020
Mars 2020 is a Mars rover mission by NASA's Mars Exploration Program that includes the Perseverance rover with a planned launch on 17 July 2020, and touch down in Jezero crater on Mars on 18 February 2021.[21][22] It will investigate an astrobiologically relevant ancient environment on Mars and investigate its surface geological processes and history, including the assessment of its past habitability, the possibility of past life on Mars, and the potential for preservation of biosignatures within accessible geological materials.[23][24] It will cache sample containers along its route for a potential future Mars sample-return mission.[24][25][26] The Mars 2020 mission was announced by NASA on 4 December 2012 at the fall meeting of the American Geophysical Union in San Francisco.[27] The Perseverance rover's design is derived from the Curiosity rover, and will use many components already fabricated and tested, new scientific instruments and a core drill.[28] It will also carry a helicopter drone.
Mars Global Remote Sensing Orbiter and Small Rover
The Mars Global Remote Sensing Orbiter and Small Rover (HX-1) is a planned project by China to deploy an orbiter and rover on Mars.[29] The mission is planned to be launched in July or August 2020[30][31] with a Long March 5 heavy lift rocket.[32][33][34] Its stated objectives are to search for evidence of both current and past life, and to assess the planet's environment.[35][36]
Mangalyaan 2
Mars Orbiter Mission 2 (MOM 2), also called Mangalyaan-2, is India's second interplanetary mission planned for launch to Mars by the Indian Space Research Organisation (ISRO). As per some reports emerged, the mission was to be an orbiter to Mars proposed for 2024.[37] However, in a recorded interview in October 2019, VSSC director has indicated the inclusion of a lander and rover.[38] The orbiter will use aerobraking to lower its initial apoapsis and enter into an orbit more suitable for observations.[39][40][41]
Hope Mars Mission
The Hope Mars Mission is a space exploration probe mission to Mars built by the United Arab Emirates and set for launch in 2020. Upon launch, it will become the first mission to Mars by any Arab or Muslim majority country. The probe will study the Martian atmosphere and provide details regarding the daily climate and through seasonal cycles, the weather events in the lower atmosphere such as dust storms, as well as the weather on Mars different geographic areas. The probe will attempt to answer the scientific community questions of why Mars atmosphere is losing hydrogen and oxygen into space and the reason behind Mars drastic climate changes.
Asteroids
An article in science magazine Nature suggested the use of asteroids as a gateway for space exploration, with the ultimate destination being Mars. In order to make such an approach viable, three requirements need to be fulfilled: first, "a thorough asteroid survey to find thousands of nearby bodies suitable for astronauts to visit"; second, "extending flight duration and distance capability to ever-increasing ranges out to Mars"; and finally, "developing better robotic vehicles and tools to enable astronauts to explore an asteroid regardless of its size, shape or spin." Furthermore, using asteroids would provide astronauts with protection from galactic cosmic rays, with mission crews being able to land on them without great risk to radiation exposure
Lucy
Lucy, part of NASA's Discovery Program, is scheduled to launch in October 2021 to explore six Trojan Asteroids and a Main Belt asteroid. The two Trojan swarms ahead of and behind Jupiter are thought to be dark bodies made of the same material as the outer planets that were pulled into orbit near Jupiter.[42] Lucy will be the first mission to study the Trojans, and scientists hope the findings from this mission will revolutionize our knowledge of the formation of the solar system. For this reason, the project is named after Lucy, a fossilized hominid that provided insight on the evolution of humans. The asteroids studied are ancient fossils of planet formation which could hold clues to the origins of life on Earth.[43]
Psyche
The Psyche spacecraft, part of NASA's Discovery Program, is scheduled to launch at the end of 2022 to 16 Psyche, a metallic object in the asteroid belt.[44] 16 Psyche is 130 miles (210 km) wide, and it is made almost entirely of iron and nickel instead of ice and rock. Because of this unique composition, scientists believe it is the remnants of a planet's core that lost its exterior through a series of collisions, but it is possible that 16 Psyche is only unmelted material.[42] NASA hopes to obtain information about planetary formation from directly studying the exposed interior of a planetary body, which would otherwise not be possible.[45]
OSIRIS-REx
The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid study and sample-return mission.[46] The mission's main goal is to obtain a sample of at least 60 grams (2.1 oz) from 101955 Bennu, a carbonaceous near-Earth asteroid, and return the sample to Earth for a detailed analysis. The material returned is expected to enable scientists to learn more about the formation and evolution of the Solar System, its initial stages of planet formation, and the source of organic compounds that led to the formation of life on Earth.[47] If successful, OSIRIS-REx will be the first U.S. spacecraft to return samples from an asteroid. The Lidar instrument used aboard the OSIRIS-REx was built by Lockheed Martin, in conjunction with the Canadian Space Agency.[48][49]
OSIRIS-REx was launched on 8 September 2016, flew past Earth on 22 September 2017, and reached the proximity of Bennu on 3 December 2018,[50] where it began analyzing its surface for a target sample area over the next several months. It is expected to return with its sample to Earth on 24 September 2023.[51]
Gas Giants
JUICE
The JUpiter ICy moons Explorer (JUICE) is an interplanetary spacecraft in development by the European Space Agency (ESA) with Airbus Defence and Space as the main contractor. The mission is being developed to visit the Jovian system focused on studying three of Jupiter's Galilean moons: Ganymede, Callisto, and Europa (excluding the more volcanically active Io) all of which are thought to have significant bodies of liquid water beneath their surfaces, making them potentially habitable environments. The spacecraft is set for launch in June 2022 and would reach Jupiter in October 2029 after five gravity assists and 88 months of travel. By 2033 the spacecraft should enter orbit around Ganymede for its close up science mission and becoming the first spacecraft to orbit a moon other than the moon of Earth.
Europa Clipper
Europa Clipper[52] (previously known as Europa Multiple Flyby Mission) is an interplanetary mission in development by NASA comprising an orbiter. Set for a launch in 2025,[53] the spacecraft is being developed to study the Galilean moon Europa through a series of flybys while in orbit around Jupiter.
This mission is a scheduled flight of the Planetary Science Division, designated a Large Strategic Science Mission, and funded under the Planetary Missions Program Office's Solar System Exploration program as its second flight.[54][55] It is also supported by the new Ocean Worlds Exploration Program.[56] Europa Clipper will perform follow-up studies to those made by the Galileo spacecraft during its eight years in Jupiter orbit, which indicated the existence of a subsurface ocean underneath Europa's ice crust. Plans to send a spacecraft to Europa were initially conceived with projects such as Europa Orbiter and Jupiter Icy Moons Orbiter, in which a spacecraft would be injected into orbit around Europa. However, due to the adverse effects of radiation from Jupiter's magnetosphere in Europan orbit, it was decided that it would be safer to inject a spacecraft into an elliptical orbit around Jupiter and make 45 close flybys of the moon instead. The mission began as a joint investigation between the Jet Propulsion Laboratory and the Applied Physics Laboratory.
Breakthrough Enceladus
Breakthrough Enceladus is an astrobiology space probe mission concept to explore the possibility of life on Saturn's moon, Enceladus.[57] In September 2018, NASA signed a collaboration agreement with Breakthrough to jointly create the mission concept.[58] This mission would be the first privately funded deep space mission.[59] It would study the content of the plumes ejecting from Enceladus's warm ocean through its southern ice crust.[60] Enceladus's ice crust is thought to be around two to five kilometers thick,[61] and a probe could use an ice-penetrating radar to constrain its structure.[62]
Space telescopes
CHEOPS
CHEOPS (Characterising Exoplanets Satellite) is a planned European space telescope for the study of the formation of extrasolar planets. The launch window for CHEOPS is the fourth quarter of 2019.[63]
The mission aims to bring an optical Ritchey–Chrétien telescope with an aperture of 30 cm, mounted on a standard small satellite platform, into a Sun-synchronous orbit of about 700 km (430 mi) altitude. For the planned mission duration of 3.5 years, CHEOPS is to examine known transiting exoplanets orbiting bright and nearby stars.[64]
PLATO
Planetary Transits and Oscillations of Stars (PLATO) is a space telescope under development by the European Space Agency for launch in 2026.[65] The mission goals are to search for planetary transits across up to one million stars, and to discover and characterize rocky extrasolar planets around yellow dwarf stars (like our sun), subgiant stars, and red dwarf stars. The emphasis of the mission is on earth-like planets in the habitable zone around sun-like stars where water can exist in liquid state.[66] It is the third medium-class mission in ESA's Cosmic Vision programme and named after the influential Greek philosopher Plato, the founding figure of Western philosophy, science and mathematics. A secondary objective of the mission is to study stellar oscillations or seismic activity in stars to measure stellar masses and evolution and enabling the precise characterization of the planet host star, including its age.[67]
James Webb Space Telescope
The James Webb Space Telescope (JWST or "Webb") is a space telescope that is planned to be the successor to the Hubble Space Telescope.[68][69] The JWST will provide greatly improved resolution and sensitivity over the Hubble, and will enable a broad range of investigations across the fields of astronomy and cosmology, including observing some of the most distant events and objects in the universe, such as the formation of the first galaxies. Other goals include understanding the formation of stars and planets, and direct imaging of exoplanets and novas.[70]
The primary mirror of the JWST, the Optical Telescope Element, is composed of 18 hexagonal mirror segments made of gold-plated beryllium which combine to create a 6.5-meter (21 ft; 260 in) diameter mirror that is much larger than the Hubble's 2.4-meter (7.9 ft; 94 in) mirror. Unlike the Hubble, which observes in the near ultraviolet, visible, and near infrared (0.1 to 1 μm) spectra, the JWST will observe in a lower frequency range, from long-wavelength visible light through mid-infrared (0.6 to 27 μm), which will allow it to observe high redshift objects that are too old and too distant for the Hubble to observe.[71] The telescope must be kept very cold in order to observe in the infrared without interference, so it will be deployed in space near the Earth–Sun L2 Lagrangian point, and a large sunshield made of silicon- and aluminum-coated Kapton will keep its mirror and instruments below 50 K (−220 °C; −370 °F).[72]
Crewed missions
Commercial Crew Development
Commercial Crew Development (CCDev) is a human spaceflight development program that is funded by the U.S. government and administered by NASA. CCDev will result in US and international astronauts flying to the International Space Station (ISS) on privately operated crew vehicles.
Operational contracts to fly astronauts were awarded in September 2014 to SpaceX and Boeing.[73] Test flights of Dragon 2 and CST-100 are scheduled for 2019.[74] Pending completion of the demonstration flights, each company is contracted to supply six flights to ISS between 2019 and 2024.[75] The first group of astronauts was announced on 3 August 2018.[76]
Artemis program
The Artemis program is an ongoing crewed spaceflight program carried out by NASA, U.S. commercial spaceflight companies, and international partners such as ESA,[77] with the goal of landing "the first woman and the next man" on the Moon, specifically at the lunar south pole region by 2024. Artemis would be the next step towards the long-term goal of establishing a sustainable presence on the Moon, laying the foundation for private companies to build a lunar economy, and eventually sending humans to Mars.
In 2017, the lunar campaign was authorized by Space Policy Directive 1, utilizing various ongoing spacecraft programs such as Orion, the Lunar Gateway, Commercial Lunar Payload Services, and adding an undeveloped crewed lander. The Space Launch System will serve as the primary launch vehicle for Orion, while commercial launch vehicles are planned for use to launch various other elements of the campaign.[78] NASA requested $1.6 billion in additional funding for Artemis for fiscal year 2020,[79] while the Senate Appropriations Committee requested from NASA a five-year budget profile[80] which is needed for evaluation and approval by Congress.[81][82]
SpaceX Starship
The SpaceX Starship is planned to be a spacecraft launched as the second stage of a reusable launch vehicle. The concept is under development by SpaceX, as a private spaceflight project.[83] It is being designed to be a long-duration cargo- and passenger-carrying spacecraft.[84] While it will be tested on its own initially, it will be used on orbital launches with an additional booster stage, the Super Heavy, where Starship would serve as the second stage on a two-stage-to-orbit launch vehicle.[85] The combination of spacecraft and booster is called Starship as well.[86]
Limitations with deep space exploration
The future possibilities for deep space exploration are currently held back by a set of technical, practical, astronomical, and human limitations, which define the future of manned and unmanned space exploration. As of 2017, the farthest any man-made probe has traveled is the current NASA mission Voyager 1,[87] currently about 13 billion miles (21 billion km), or 19.5 light hours away from the Earth, while the nearest star is around 4.24 light years away.
Technical limitations
The current status of space-faring technology, including propulsion systems, navigation, resources and storage all present limitations to the development of human space exploration in the near future.
Distances
The astronomical order of magnitude of the distance between us and the nearest stars is a challenge for the current development of space exploration. At our current top speed of 157,100 miles per hour (252,800 km/h), the Helios 2 probe would arrive at the nearest star, Proxima Centauri, in around 18,000 years,[88] much longer than a human lifespan and therefore requiring much faster transportation methods than currently available. It is important to note that this top speed was achieved due to the Oberth effect where the spacecraft was sped up by the Sun's gravity. The fastest escape velocity from the Solar System is that of Voyager 1 at 17 km/s.
Propulsion and fuel
In terms of propulsion, the main challenge is the liftoff and initial momentum, since there is no friction in the vacuum of space. Based on the missions goals, including factors such as distance, load and time of flight, the type of propulsion drive used, planned to use, or in design varies from chemical propellants, such as liquid hydrogen and oxidizer[90] (Space Shuttle Main Engine), to plasma[89] or even nanoparticle propellants.[91]
As for future developments, the theoretical possibilities of nuclear based propulsion have been analyzed over 60 years ago, such as nuclear fusion (Project Daedalus) and nuclear pulse propulsion (Project Longshot),[92] but have since been discontinued from practical research by NASA. On the more speculative side, the theoretical Alcubierre drive presents a mathematical solution for “faster-than-light” travel, but it would require the mass-Energy of Jupiter, not to mention the technical issues.[93]
Human limitations
The human element in manned space exploration adds certain physiological and psychological issues and limitations to the future possibilities of space exploration, along with storage and sustenance space and mass issues.
Physiological issues
The transitioning gravity magnitudes on the body is detrimental to orientation, coordination, and balance. Without constant gravity, bones suffer disuse osteoporosis, and their mineral density falls 12 times faster than the average elderly adult's.[94] Without regular exercise and nourishment, there can be cardiovascular deterioration and loss in muscle strength.[95] Dehydration can cause kidney stones,[96] and constant hydro-static potential in zero-g can shift body fluids upwards and cause vision problems.[97]
Furthermore, without Earth's surrounding magnetic field as a shield, solar radiation has much harsher effects on biological organisms in space. The exposure can include damage to the central nervous system, (altered cognitive function, reducing motor function and incurring possible behavioral changes), as well as the possibility of degenerative tissue diseases.
Psychological issues
According to NASA, isolation in space can have detrimental effects on the human psyche. Behavioral issues, such as low morale, mood-swings, depression, and decreasing interpersonal interactions, irregular sleeping rhythms, and fatigue occur independently to the level of training, according to a set of NASA's social experiments.[98] The most famous of which, Biosphere 2,[99] was a 2 year long, 8 person crew experiment in the 1990s, in an attempt to study human necessities and survival in an isolated environment. The result of which were stressed interpersonal interactions and aloof behavior, including limiting and even ceasing contact between crew members,[98] along with failing to sustain a lasting air-recycling system and food supply.[100]
Resources and sustenance
Considering the future possibility of extended, manned missions, food storage and resupply are relevant limitations. From a storage point of view, NASA estimates a 3-year Mars mission would require around 24 thousand pounds (11 t) of food, most of it in the form of precooked, dehydrated meals of about 1.5 pounds (0.68 kg) a portion.[101] Fresh produce would only be available in the beginning of the flight, since there would not be refrigeration systems. Water's relative heavy weight is a limitation, so on the International Space Station (ISS) the use of water per person is limited to 11 litres (2.9 US gal) a day, compared to the average Americans' 132 litres (35 US gal).[101]
As for resupply, efforts have been made to recycle, reuse and produce, to make storage more efficient. Water can be produced through chemical reactions of Hydrogen and Oxygen in fuel cells,[101] and attempts and methods of growing vegetables in micro-gravity are being developed and will continue to be researched. Lettuce has already successfully grown in the ISS's "Veggie plant growth system", and has been consumed by the astronauts, even though large-scale plantation is still impractical,[102] due to factors such as pollination, long growth periods, and lack of efficient planting pillows.
Artificial Intelligence and Robotic Space Craft Development
The idea of using high level automated systems for space missions has become a desirable goal to space agencies all around the world. Such systems are believed to yield benefits such as lower cost, less human oversight, and ability to explore deeper in space which is usually restricted by long communications with human controllers. Autonomy will be a key technology for the future exploration of our solar system, where robotic spacecraft will often be out of communication with their human controllers.
Autonomous systems
Autonomy is defined by three requirements:
- The ability to make and carry out decisions on their own, based on information on what they sensed from the world and their current state.
- The ability to interpret the given goal as a list of actions to take.
- The ability to fail flexibly, meaning they are able to continuously change their actions based on what is happening within their system and their surrounding.
Currently, there are many projects trying to advance space exploration and space craft development using AI.[103]
NASA's autonomous science experiment
NASA began its autonomous science experiment (ASE) on Earth Observing-1 (EO-1), which is NASA's first satellite in the millennium program, Earth-observing series launched on November 21, 2000. The autonomy of these satellites is capable of on-board science analysis, re-planning, robust execution, and model-based diagnostic. Images obtained by the EO-1 are analyzed on-board and down linked when a change or interesting event occurs. The ASE software has successfully provided over 10,000 science images. This experiment was the start of many that NASA devised for AI to impact the future of space exploration.
Artificial Intelligence Flight Adviser
NASA's goal with this project is to develop a system that can aid pilots by giving them real-time expert advice in situations that pilot training does not cover or just aid with a pilot's train of thought during flight. Based on the IBM Watson cognitive computing system, the AI Flight Adviser pulls data from a large database of relevant information like aircraft manuals, accident reports, and close-call reports to give advice to pilots. In the future, NASA wants to implement this technology to create fully autonomous systems, which can then be used for space exploration. In this case, cognitive systems will serve as the basis, and the autonomous system will completely decide on the course of action of the mission, even during unforeseen situations.[104] However, in order for this to happen, there are still many supporting technologies required.
In the future, NASA hopes to use this technology not only in flights on earth, but for future space exploration. Essentially, NASA plans to modify this AI flight Advisor for Longer range applications. In addition to what the technology is now, there will be additional cognitive computing systems that can decide on the right set of actions based upon unforeseen problems in space. However, in order for this to be possible, there are still many supporting technologies that need to be enhanced.
Stereo vision for collision avoidance
For this project, NASA's goal is to implement stereo vision for collision avoidance in space systems to work with and support autonomous operations in a flight environment. This technology uses two cameras within its operating system that have the same view, but when put together offer a large range of data that gives a binocular image. Because of its duo-camera system, NASA's research indicate that this technology can detect hazards in rural and wilderness flight environments. Because of this project, NASA has made major contributions toward developing a completely autonomous UAV. Currently, Stereo Vision can construct a stereo vision system, process the vision data, make sure the system works properly, and lastly performs tests figuring out the range of impeding objects and terrain. In the future, NASA hopes this technology can also determine the path to avoid collision. The near-term goal for the technology is to be able to extract information from point clouds and place this information in a historic map data. Using this map, the technology could then be able to extrapolate obstacles and features in the stereo data that are not in the map data. This would aid with the future of space exploration where humans can't see moving, impeding objects that may damage the moving space craft.[105]
Benefits of AI
Autonomous technologies would be able to perform beyond predetermined actions. They would analyze all possible states and events happening around them and come up with a safe response. In addition, such technologies can reduce launch cost and ground involvement. Performance would increase as well. Autonomy would be able to quickly respond upon encountering an unforeseen event, especially in deep space exploration where communication back to Earth would take too long. Space exploration could provide us with the knowledge of our universe as well as incidentally developing inventions and innovations. Traveling to Mars and farther could encourage the development of advances in medicine, health, longevity, transportation, communications that could have applications on Earth.[103]
Robotic spacecraft development
Energy
Solar panels
Changes in space craft development will have to account for an increased energy need for future systems. Spacecrafts heading towards the center of our solar system will include enhanced solar panel technology to make use of the abundant solar energy surrounding them. Future solar panel development is aimed at their working more efficiently while being lighter.[106]
Radioisotope Thermoelectric Generators
Radioisotope Thermoelectric Generators (RTEG or RTG) are solid-state devices which have no moving parts. They generate heat from the radioactive decay of elements such as plutonium, and have a typical lifespan of more than 30 years. In the future, atomic sources of energy for spacecraft will hopefully be lighter and last longer than they do currently.[107] They could be particularly useful for missions to the Outer Solar System which receives substantially less sunlight, meaning that producing a substantial power output with solar panels would be impractical.
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