The exploration of space is conducted by unmanned robotic probes and human spaceflight as well as through astronomical means (which we will not be dealing with here). The usual reasons for undertaking all this are scientific curiosity, usually presented, with some justification, as a universal aspect of human nature. Apart from questions about our environment, this includes our curious interest in some questions about ourselves, not only in terms of the origins of life but more practical questions about the survival of our species as well as philosophical questions about our meaning, if we have any, in a huge material universe.
Our footprint in space is very recent (a matter of around half a century) and very small-scale. The longest human occupation of space is represented by the International Space Station, in continuous use for well over 14 years. Valeri Polyakov made a record single spaceflight of almost 438 days aboard the Mir space station. Long-term stays in space have revealed issues with bone and muscle loss in low gravity, immune system suppression and radiation exposure. As for whether other life exists which would impact on our own sense of uniqueness as an evolved species, some of the main locations for future astrobiological investigation are on Enceladus, Europa, Mars, and Titan. All these locations require at least some form of lander to ask any serious questions about extra-terrestrial life.
We can perhaps take as special pleading spin-off effects (though these exist), the value to earthlings of asteroid or moon-mining (since this material is largely for use off-world in a circular argument about value) and its inspirational aspects educationally since they all rather beg the question of whether a space programme necessarily is the best means of achieving any of the proposed ends. There may also be some fluffy stuff about human political universality that sometimes masks national strategic advantage or special interest lobbying but, lately, special interests have taken to trying to persuade funding bodies (basically, this involves the transfer of funds from the general economy, including current welfare and economic and social investment) to part with cash on the basis of some future existential risk from space – either as direct defensive manoeuvres or in terms of the scientific understanding necessary to avert or survive them in the longer term. Existential risk is not seriously presented as one of aliens in saucers but mostly as a matter of asteroids or other celestial events. These are legitimate concerns though there is some potential over-promising involved as to what may be possible in terms of protection.
Another line of persuasion likes to suggest that because (allegedly) we humans are going to destroy our own planet, then we must find others to settle in order to survive, begging the question of what it actually means to individuals in having the species survive on such terms. This approach tends to ignore the rather brute facts of vast distances and the effects of radiation and non-earth conditions on biology as well as the expense of such projects (which would be geared almost certainly to the survival of the relative few over the masses stuck on earth). As we will see, the prospects of travelling beyond the solar system to find habitable exo-planets is extremely distant– the effort simply to reach near moons and Mars may take decades yet.
The claims of non-asteroid-related earthly destruction are as likely to be apocalyptic hogwash created by various ideological or scientific lobby groups as genuinely evidence-based worries but the interest in expanding human presence is undoubtedly a primal drive of the species and should not be underestimated or dismissed. Perhaps it is just the tortuous attempts to give rhetorical justification for the acquisitive and expansionary urges of humanity that we should regard with cynicism. However, what we undoubtedly see at the beginning of the twenty-first century is a marked increase in human and robotic space exploration.
After The Cold War
The US human space programme is still a little unclear as to final strategy in an age of economic austerity (though a programme of work exists as a result of the NASA Authorization Act 2010) but the old Soviet programme died with the collapse of the Soviet model. The current trend has been for programmes to be preferred that are relatively cost-effective (making use of robotics more than humans to expand horizons) and focused on scientific discovery within the solar system. Major scientific projects also tend to be spread among many more nations, either directly collaborative or as independent operations that have some element of co-ordination. The more deliberately scientific and robotic and the less human or existential, the more likely that collaboration will be involved though this may change if the feasibility and costs of asteroid management increase.
The current general effect is to create a more diffuse understanding of immediate surroundings in space and to develop basic skills for the future rather than expand immediately the species territory (indeed, the withdrawal from the moon had indicated a reduction in such ambitions in the recent past).Although there are plans to return to the Moon and explore Mars, more distant threats and opportunities (such as exo-planets and new interstellar drives) are left to astronomical science and even cosmology and particle physics. Efforts have largely been concentrated on what is near to hand for very practical reasons.
However, an era of relative pause seems to be coming slowly to an end before a secondary leap forward based on the possibilities of dealing with material threats, on the assumed resolution of earthly economic difficulties and on that hoary old competition for advantage between States. The legal framework for space exploration is set by the Outer Space Treaty which has been ratified by all current spacefaring nations (as of 2012).
NASA’s Space Shuttle programme no longer counts as space exploration if ever it did. It formally ended at the end of August 2011 in any case. The tasks performed by the Shuttle are now done by many different craft either currently flying or in advanced development and should really be considered logistics for existing capability.
The International Space Station is a joint project of NASA, Roscosmos, JAXA, ESA, and CSA with ownership and use of the space station established by intergovernmental treaties and agreements. The station is divided into two sections, the Russian Orbital Segment (ROS) and the United States Orbital Segment (USOS).
The American portion is funded until at least 2024 while Roskosmos has endorsed the continued operation of ISS through to the same date but has proposed using elements of the ROS to construct a new Russian space station called OPSEK. It was understood that Roscosmos and NASA had agreed to collaborate on the development of a replacement for the current ISS but this has yet to be confirmed by the US and it may fall victim to recent political difficulties between the two nations.
The Bush Administration Constellation Program (for a return to the Moon by 2020) was judged inadequately funded and unrealistic by an expert review panel reporting in 2009. The Obama Administration then proposed a revision (NASA Authorization Act 2010) to a) focus on the development of the capability for crewed missions beyond low Earth orbit (LEO), b) extend the operation of the ISS beyond 2020 (and now agreed), c) transfer the development of launch vehicles for human crews from NASA to the private sector (see above), and d) develop technology to enable missions such as Earth to the Moon, on the Moon, from the Earth to the near-Sun, to investigate the near-earth asteroids, and to take craft into Phobos or Mars orbit (clearly with the aim of landing on Mars).
For missions beyond Low Earth Orbit, NASA is building the Space Launch System and the Orion spacecraft. The Space Launch System (SLS) is designed to carry the Orion Multi-Purpose Crew Vehicle, with important cargo, equipment, and science experiments to Earth's orbit and destinations beyond. It will serve as a back-up for commercial and international partner transportation services to the International Space Station, incorporating the technology of the Space Shuttle program and Constellation programmes. The first developmental flight is targeted for end-2017
Other National Efforts
Roskosmos, the Russian Space Agency, meanwhile, is still dealing with the after effects of the collapse of the Soviet Union. The current intention appears to be full re-nationalisation and a return to active programmes, including (in principle) a return to the Moon. There is a major overhaul of the Agency being undertaken to deal with recent serious failures in the proton-M programme and inherent inefficiencies. These involve a concentration of talent. Layoffs and productivity improvements are planned. For commercial and political reasons, one may reasonably expect a Russian return to the sector within the next decade or so. If so, there may be a competitive interest emerging from the US if and once it is clear that the Russians can, in fact, create a more efficient and cost-effective state run capability.
The Ukrainian Space Agency, the other heir to the old Soviet capability, was always going to be an adjunct of Roskosmos as the industrial supplier to Russian capability which has the main launch capacity. Its future must reasonably be in doubt or (at least) limited until recent political and economic difficulties have been resolved. The best talent may be attracted across to the new improved Roskosmos. Chinese plans include a permanent 60-ton multi-modulspace station by 2020 and crewed expeditions to the Moon and Mars. The European Union is apparently considering manned missions to the moon and to Mars within the coming century but faces economic and organisational issues no less difficult than those of Russia. It is highly active in robotic scientific missions beyond Mars. Japan, and India also plan future manned space missions to the Moon.
In other words, though relatively cash strapped and with no really firm strategic plans yet fully funded, the two strategic powers of the Cold war, the two most populous rising nations and the more advanced non-US elements of the West (European Union and Japan) all have a manned journey to the Moon and possibly Mars on their medium-term agenda. In addition some private sector interests (largely US) are promoting space tourism (not strictly space exploration) and private space exploration of the Moon.
Between Earth and The Sun
From an unmanned scientific perspective, there is continued interest in the Sun because of its environmental effects.
|BepiColombo en route to Mercury|
The third mission to Mercury [BepiColombo] is scheduled to arrive in 2020 and includes two probes. It is a joint mission between Japan and the European Space Agency. MESSENGER (already in orbit around Mercury) and BepiColombo will gather complementary data to help further understanding of the findings of the first flyby mission, Mariner 10 (1973).
Venus had a great deal of attention from the old Soviet space research programme but does not seem to be a current priority for major investment although there is an Indian Venus Orbiter Mission planned for this year and a Russian brief lander and weather balloon operation targeted for 2024.
Manned Landing Targets
The Moon remains of interest for robotic missions but the key future event (assuming that none of the other planned human interventions come to fruition before this date) is NASA’s Exploration Mission 2 or EM-2, the first crewed mission of NASA's Orion on the Space Launch System. In 2006 NASA announced they were planning to build a permanent Moon base with continual presence by 2024 which ties in with the date for guaranteed funding for the ISS. The ultimate mission is to restart manned exploration of the Solar System from this base line. In 2021, a crew will undertake a practice flyby of a captured asteroid in lunar orbit (see later) and this will be the first time humans will have left Low Earth Orbit since Apollo 17 [December 1972]. If someone else does not get there first and all goes well, this will be a major psychological boost for US scientific leadership and give the US a new lead in manned solar exploration with the obvious next target being Mars and the physical exploration of the Moon itself.
|Phobos in relation to Mars|
Mars is the main target in terms of matching the past cultural impact of the Moon landings. The planet has been the subject of many robotic missions but with a very high failure rate and at huge cost. Around two-thirds of all spacecraft fail before completing their missions. There is talk of a Great Galactic Ghoul which eats Mars probes. India, however, has become the first country to achieve success at its first attempt. Its Mars Orbiter Mission (MOM) was also one of the least expensive interplanetary missions ever undertaken with an approximate total cost of US$73 million. A Russian orbiter space mission failed to reach Phobos (2011) which is regarded as a possible ‘transhipment’ point for spaceships travelling to Mars. However, lessons being learned, it is only a matter of time before some attempt is made to land human beings on the planet whether via Phobos or not.
Between Mars and Uranus
Beyond Mars, we are not only into purely robotic missions but the very idea of manned missions are meaningless until the problems presented by the Phobos-Mars system are resolved. Missions beyond Mars are currently related solely to scientific investigation or the long term management of possible existential risk (related to asteroid threats or ‘space weather’). The Galileo orbiter was the most significant scientific mission (1995-2003) in dealing with Jupiter – the planet would probably though not certainly be impossible to land on although it has around 60 known moons. NASA’s future probes include Juno spacecraft, launched in 2011, which will enter a polar orbit around Jupiter to see if it has a rocky core which theoretically (although it is unlikely to be practical) might allow a human to land on its surface. The European Space Agency selected the L1-class JUICE mission in 2012 as part of its Cosmic Vision programme to explore three of Jupiter's Galilean moons, with a possible Ganymede lander provided by Roscosmos. JUICE is proposed to be launched in 2022.
Saturn is still being orbited by the Cassini-Huyghens Orbiter (2004) and providing data long after its expected ending date. The Huygens probe successfully landed on Titan (2004/2005), the only moon (other than Earth's own Moon) to be successfully explored with a lander. This operation was a joint US-European-Italian project.
|Cassini-Huyghens in orbit around Saturn|
The success of Cassini-Huyghens has resulted in proposals for another major US-European mission with preference given to a 2020 in-depth exploration of Jupiter's moons with a focus on Europa, Ganymede and Jupiter's magnetosphere [Europa Jupiter System Mission – Laplace). There are other proposed US and European missions. Jupiter’s and Saturn’s moons should be regarded as of joint significance in this context. Whether significant Russian or Asian involvement will be part of these Missions is a political but also a capability issue which will be resolved in the coming decade.
If Mars represents the realistic next limit of human exploration (with theoretical plans for Jupiter and its moons), Jupiter and Saturn’s moons and their mother planets are where most of the scientific robotic investment is taking place. From this point on, we are almost certainly speaking of unmanned probes this century. The exploration of Uranus, for example, has only been via the Voyager 2 spacecraft (1986). No other visits are currently planned. There are proposals but nothing approved.
Voyager 2 also flew by Neptune (1989) but the planet has not even had an orbiter yet and it is not seriously a current candidate for significant expenditure. It is probably no accident that a lack of interest appeared just as the old Soviet system collapsed and the incentive for high expenditures in space began to evaporate.
The controllers of Voyager 1 had preferred to fly by Titan than head for Pluto (now regarded as a dwarf planet) while Voyager 2’s trajectory was nowhere near it. However, Pluto is of great scientific interest. We currently have the excitement of a mission arriving (closest approach) on July 14th this year. New Horizons got US funding in 2003 and 2006. Scientific observations of Pluto will already have begun around January and they will continue well into August. It also happens to be the fastest spaceship ever launched at 36,000 mph.
Existential Threat - Asteroids
Asteroids are of great interest because of their ultimate existential threat to the species. Several asteroids have been visited by probe since 1991. The first unmanned landing on an asteroid was that of the NEAR Shoemaker probe in 2000 after an orbital survey. NASA’s Dawn Mission (launched in 2007) is targeting the dwarf planet Ceres and the Asteroid 4 Vesta (two of the three largest asteroids). The first colour map of Ceres was released while we were drafting this Note (April 13th, 2015).
|The Dawn Mission|
Beyond the Solar System and Summary
There is much to learn but the costs for earth-based powers (the only ones we know of) suggest that most activity will be related to four central ‘war aims’:
- the understanding of space weather (centred on the Sun);
- support for manned missions ultimately targeting Mars and the moons around the large planets Jupiter and Saturn;
- asteroid risk management and the potential for mining for deep space use; and,
- further scientific investigation of the frontier between Mars and Uranus in the first instance and beyond Uranus only in the second.
The main strategic development is the potential development of autonomous artificial intelligence that can be applied to unmanned missions, especially into deep space, and support for manned missions. Human activity in some senses requires a degree of ‘relearning’ although there is now an experienced body of astronauts and their non-US equivalents and travel technology is well established, though not without risk. Both long distance travel (with its unknown biological effects) and landings on the Moon, Mars and moons of other planets (including Phobos) require some a return to old skills (the Apollo Missions) and new ones, including very extended periods in cell-like conditions where (in the early cases) there may be a one way trip involved and nothing at the other end except the broadcasting of discoveries before extinction.