1. Introduction

Several methods for terraforming Mars, to make it habitable to humans, have been proposed by various authors (Graham, 2006, Moss, 2006; Zubrin & McKay, 1997). The proposals include giant orbital mirrors, controlled asteroid impacts, nuclear mining or the use of halocarbons to warm the planet and create an atmosphere (Birch, 1992; Zubrin & McKay, 1997; Fogg, 1998; Hiscox, 2000; Graham, 2004, 2006; International Space University, 2005; Marinova et al., 2005; Moss, 2006; Orme & Ness, 2007, McInnes, 2010). The general idea behind all these methods is that heating the Martian atmosphere should release carbon dioxide and other gaseous volatiles from the polar caps, permafrost and regolith reserves, triggering a runaway greenhouse effect thereby trapping heat and warming the planet. This would bring medium temperatures closer to those on Earth, and create a substantial atmosphere and planetary water cycle.

It is unknown if microbes already populate the red planet. However, it is well established that archae, bacteria, and simple eukaryotes terraformed Earth, and created its oxygen atmosphere, and were also largely responsible for the temperature extremes, from global warming to global cooling, for the first 4 billion years (Joseph 2010). Therefore, a variety of microorganisms could be also be deployed to Mars.

2. Bosch Reaction

It took 4 billion years of terraforming before oxygen levels rose sufficiently and for temperature extremes to become less extreme, thereby making Earth habitable for complex oxygen-breating creatures (Joseph 2010). Increased oxygen levels also triggered the formation of a protective ozone, which allowed for innumerable species to emerge from the ocean and beneath the soil, and to walk, crawl, or slither across the earth (Joseph 2010).

Although microbial and other means of terraforming should be considered, a more rapid method of making Mars habitable in just a few decades could be achieved through the Bosch reaction. Although the Bosch reaction has been suggested as a terraforming method for Venus and the Jovian moons, it has also been criticised for its greenhouse effect, which would be undesirable in the case of Venus (Birch, 1991, Cantrell, 2009). The Bosh reaction might be ideal for Mars.

The Bosch reaction involves gaseous carbon dioxide and hydrogen and produces solid carbon (graphite) and water vapor as follows:

The reaction requires high temperatures (530 – 730 °C), is accelerated by an iron, nickel or cobalt catalyst and is exothermal (Wilson, 1971).

How could this be useful to the terraformation of Mars? First of all, it generates heat (10% of invested heat). The water vapor produced is a strong greenhouse gas. Furthermore, black graphite dust would lower the planet’s albedo, reducing its reflectivity and warm the surface. The problem is that a consistent source of hydrogen is needed.

The Martian atmosphere weighs 25 °— 10¹⁵ kg, of which around 95% is carbon dioxide. However, an amount of 2.16 °— 10¹⁵kg of H₂ would be required for the complete conversion. Even if we assume an 100% efficiency, this is obviously not achievable. Although hydrogen is the most abundant atom in the universe, there is not enough on Mars. The only realistic source in quantities sufficient to trigger the Bosch reaction, are the two gas giants, Saturn and Jupiter. Saturn and Jupiter can be ignited, thereby transforming our solar system into a 3-star system, and warming not just Mars but Europa, Titan, and the other outer moons, making them habitable as well.

3. Igniting the Gas Giants

Jupiter and Saturn are composed mostly of hydrogen, 90% and 96% respectively (Bakos et al., 2007; Baraffe et al., 2008). A probable rocky core is surrounded by a thick layer of metallic hydrogen (78% of the planet’s radius in Jupiter’s case), liquid molecular hydrogen and a gaseous atmosphere (Bakos et al., 2007; Baraffe et al., 2008). In fact, the two planets are more similar to stars than to telluric planets. According to at least one theory of star formation, super-Jupiters sometimes collide within nebular clouds, becoming denser and more massive in size, and in response to pulsar and black hole hydrogen radiation, ignite, becoming stars (Joseph & Schild 2010).

It is well established that exoplanets the size of Neptune, Saturn, Jupiter, and those several times the size of Jupiter, consist predominantly of hydrogen and helium (Bakos et al., 2007; Baraffe et al., 2008; Nolte & Lietz, 2000, Lellouch et al., 2001); gasses which were captured by the gravity of their heavy metal cores (Ouyed et al. 1998; Joseph and Schild 2010). According to Joseph and Schild (2010), the gravity of super-super Jupiters attract gasses within the nebular cloud including and especially hydrogen, thereby becoming super-hydrogen-gas giants. Once the pressure and density of hydrogen in the centre of these super-hydrogen giants became great enough and temperatures hot enough a thermonuclear reaction is triggered, and it would ignite, with the exploding, expanding thermal energy countering the gravitational forces of contraction thereby creating equilibrium and a full blown star. In fact, super-Jupiters the size of low mass stars have been detected (Caballero et al., 2007). These super-jupiters are massive enough to trigger and ignite deuterium-fusion (Saumon et al., 1996) leading to a thermo-nuclear reaction and thus a full blown sun.

Therefore, while residing within these nebula, and following the targeting by quasars shooting streams of hydrogen into these clouds, these super-hydrogen gas giants acquire more hydrogen, becoming denser, then ignite, thereby becoming proto-stars (Joseph & Schild, 2010). If this theory is correct, then the only thing which prevents Saturn and Jupiter from igniting is their low mass and the lack of an external activating source to trigger nuclear fusion reactions. For example, a super-Jupiter, 13 times heavier than Jupiter might fuse deuterium (Saumon et al., 1996), becoming a brown dwarf. However, a super-Jupiter 75 times heavier, in response to an external trigger (e.g. pulsar/black hole radiation), might fuse hydrogen and become a proper star (Joseph & Schild 2010).

Therefore, the solution to turning Jupiter and Saturn into proto-stars, would require the accumulation of additional hydrogen and/or a thermonuclear trigger to ignite them. Joseph and Schild (2010) provide evidence indicating that pulsar and black holes stream jets of hydrogen which are captured by super-Jupiters which then ignite. Obviously, this is not a realistic scenario for igniting Jupiter or Saturn. A number of scientists have proposed creating or harnessing small-sized black holes and introducing them in Jupiter’s center. Theoretically this would provide luminous and thermal energy for several millions years (Fogg, 1989, Zubrin, 2002). Of course, as the properties of large and small black holes are not truly known, with some scientists proposing the hole is not a hole at all, but consists of gravity particles (Joseph 2010b), the idea of harnessing a black hole is, at present, not a technical possibility.

Therefore, given technical limitations, at present, the only possibility for turning either or both the gas giants into protostars would involve the triggering of a thermonuclear reaction. It is noteworthy that in 2003, when the Galileo spacecraft (using a 238Pu-based energy generator) crashed into the Jovian atmosphere there was a concern this could cause nuclear explosions triggering the ignition of Jupiter, thereby creating a second sun (Hoagland, 2003; Goliathan, 2003; Turchin, 2010); fears that were dismissed and which have been proved to be unfounded (Goliathan, 2005), as obviously, Jupiter didn’t ignite.

Galileo-type plutonium power generators do not have the power to ignite a gas giant. Instead, as proposed in this paper, these gas giants might be ignited secondary to thermonuclear stellification. Specifically, it is proposed that intense heat (apart from huge pressures inside stars) can cause hydrogen fusion. A similar process takes place inside thermonuclear bombs: a fission trigger creates temperatures of at least 35,000,000 K, which induce hydrogen fusion. Actually, the mechanism of fusion bombs is not so simple: heavy hydrogen isotopes are required (deuterium and tritium) and they need to be highly compressed in a small space (Freudenrich & Fuller, 2000). Even the supporters of Galileo-triggered ignition of Jupiter acknowledge the need for substantial deuterium and tritium amounts inside the planet in order to sustain a fusion chain reaction (Goliathan, 2003).

There are various estimations of the ²H / ¹H ratio in the gas giants, ranging between 10^--5 - 10^-4 (Nolte & Lietz, 2000, Lellouch et al., 2001). However, Ouyed et al. (1998) proposed a model of Jupiter’s interior (extended to all Jovian planets) in which large amounts of deuterium is sedimented in a deep layer (with a thickness of a few kilometers at a depth equivalent to 60% of the planet’s radius). The quantity there would be sufficient for sustaining natural ²H - ²H fusion, which, according to this theory, produces Jupiter’s excess heat (the byproduct being tritium, which decays into ³He).

Another scientific theory regarding the excess heat produced by Jovian planets may support the idea of an artificial stellification of such bodies. According to this theory, gas giants, as well as stars and maybe smaller planets (including Earth) have massive natural fission reactors in their center. In the case of stars, nuclear fission reactions would be necessary for their ignition (Herndon, 1994, 1998, 2009). Konovalov (2009) warns about the possibility of spontaneous stellification of giant planets and suggests a preemtive artificial ignition as a means for protecting Earth from direct exposure to the hydrogen ejecta (the amount of ejecta received by a planet depends on the distance between the two bodies and on the relative position of the Sun).

Be it preemptive or for the purposes of terraforming Mars and the outer Moons, how can this be accomplished? One obvious possibility is the detonation of a a several-megaton thermonuclear warhead inside the giant planet. The depth of the detonation depends on the thermal and pressure shielding of the vehicle. Carbon nanotubes can withstand pressures as high as 200 Gpa (NASA Science News, 2002). However, thermal shielding, like that used for space shuttles cannot resist temperatures higher than 1,573 K (NASA/KSC Information Technology Directorate, 2000). According to the hydrogen phase diagram (Hydropole, 2009), at this temperature, at a pressure of only a few GPa, molecular hydrogen becomes liquid. Thus, a spacecraft could reach a depth of at least 2% of Jupiter’s radius and 25% of Saturn’s (Goliathan, 2003, Goliathan, 2005), and could detonate its nuclear charge in a layer of dense, liquid molecular hydrogen.

What would happen next? There are three scenarios that one can consider. First, there is the possibility of planetary explosion (Turchin, 2010). Theoretically, the detonation would cause a rapid and violent chain reaction inside a deuterium-rich layer, and Jupiter (or Saturn) simply blows up. A ²H / ¹H ratio of at least 1 / 300 is required for this (which is not far away from the 10^-3 ratio in the deep rich layer proposed by Ouyed et al., 1998). However, there are some problems with this idea.

Considering the energy output of the deuterium fusion reaction is 12.5 MeV, the reaction of all deuterium atoms in either gas giant would produce an energy amount lower than 10³⁸ J. The gravitational binding energy is around 2 °— 10⁴⁸ J for Jupiter and 2.26 °— 10⁴⁷ J for Saturn (the gravitational binding energy, U = 3GM² / (5r), where G is the gravitational constant, M is the mass, and r is the body’s radius). Van Flandern (2002), investigating planetary explosion mechanisms, also concludes that Jovian planets cannot explode, not even by thermonuclear means. Also, it should be considered that such deuterium enriched areas would be located at depths not accessible to any spacecraft. At lower concentrations, deuterium fusion is a common process in brown dwarfs and protostars, as slow, non-explosive reaction (Van Flandern 2002).

In the second scenario, the detonation produces a fizzle. Some amounts of hydrogen fuse, an enormous quantity of energy is produced, but the temperature and shockwave disperses the surrounding fuel and the reaction cannot propagate in the planet’s mass. This is highly plausible, since nobody tried this before. In a different version of this scenario, a self-sustainable fusion chain reaction is triggered, but only in a limited hydrogen layer. Thus the planet becomes like one the hot gas giants discovered in other stellar systems (Herndon, 2009; note that according to this theory hot Jupiter exoplanets have fusion reactions in deep layers around their cores and these are triggered by slow fission reactions).

In the last scenario, the hydrogen density around the detonation site and the deuterium concentration are high enough to support a massive explosion. The shockwave presses the underlying fuel towards the planet’s core, preventing it from dissipating. The chain reaction propagates in a substantial part of the planet’s mass, and becomes self-sustainable. Jupiter or Saturn ignites as a small star, delivering light and heat to its satellites.

4. Effects on Mars and Earth

Stellifying the gas giants could be a useful tool in the colonization and terraformation of their satellites. But would the heat produced be enough to sufficiently warm Mars? Might Mars (or even the Earth) be impacted negatively?

When a star ignites, it ejects its outer layers (around 10% of its mass) into space. This ejecta consists mostly of high velocity waves of hot ionized hydrogen (van der Worp, 2003; Joseph and Schild 2010). Might Mars and Earth, be roasted by these hot hydrogen ions? The estimation of the total mass of ejecta received by a planet can be done according to the following formula:

Mars’s surface is 144,798,500 km². The minimum distance between Mars and Jupiter is around 3.7 AU, while the minimum distance form Mars to Saturn is 8.08 AU (1 AU = 150 °— 10⁶ km). Considering a 10% ejecta (equal to 0.19 °— 10²⁷ kg for Jupiter and 0.57 °— 10²⁶ kg in Saturn’s case), the amount received by Mars would be around 7.15 °— 10¹⁵ kg from Jupiter and 0.45 °— 10¹⁵ kg from Saturn.

As stated above, 2.16 °— 10¹⁵ kg of hydrogen would be needed for a complete conversion of the Martian atmosphere (assuming 100% efficiency). However, the Bosch reaction’s efficiency is usually lower than 10 – 20%. Although the Martian surface is rich in iron, most of it is ferric iron, while only reduced iron can serve as a catalyst (Otsuji et al., 1987, Kato et al., 1994).

Heat necessary for the process would be provided by the temperature of the ejecta, probably comparable to that of the solar wind (which ranges from 10⁴ to 10⁵ K at 1-10 AU from the source; Richardson & Smith, 2003, Ng et al., 2007).

Assuming a 10% efficiency, the reaction would cover each square meter of the Martian surface with 4.47 kg of black, light-absorbing graphite, in case of Jupiter’s ignition, and 0.93 kg from Saturn.

For every gram of carbon produced at 650 °C, the reaction releases 2.3 °— 10³ J of thermal energy (Holmes et al., 1970). For the entire atmosphere, this will instantly increase the temperature by around 78 K (Jupiter ejecta) and more than 16 K (Saturn ejecta; these calculations are estimative and do not take in consideration heat radiation into space).

Some authors agree that a temperature raise by only 4 – 25 K is required to sublimate enough of the planet’s carbon dioxide reserves in order to trigger the runaway greenhouse effect (McKay et al., 1991, Zubrin & McKay, 1997, McKay, 2007, McInnes, 2010).

Obviously, from safety reasons, the stellification should take place only when Earth and the target planet are at a maximum distance (i.e. when Jupiter or Saturn is in conjunction with the Sun). The amount of ejected elements received would be 9.5 °— 10¹⁵ kg from Jupiter and 0.914 °— 10¹⁵ kg from Saturn. Compared to the 5 °— 10¹⁸ kgterrestrial atmosphere, these quantities represent only 0.19%, respectively 0.019%.

However, it should be taken in calculation that a great part of the ejecta would be deflected by the Sun and by our planet’s magnetosphere.

What would be the luminous and thermal effect of two newborn stars in our Solar System? It is difficult to estimate precisely, but it is well known that there is a direct relation between luminosity of a star (L) and its mass (more exactly, L is directly proportional to M^q, where q is a factor which varies, according to the stellar type, between 2.7 and 4, Angelov, 1993). The irradiance (the power received by a planet’s surface from a star) is calculated according to the formula:

Another important issue to consider is the gravitational effect of the process. Stellification would cause a 10% mass loss of the respective celestial body. The gravitational attraction force between Jupiter and Earth (F = GM¹M²/D²) is around 21 °— 10¹⁵ N at the minimum distance (100 times lower than that between Earth and the Moon). Jupiter’s mass influences the eccentricity of Earth’s orbit. However, even if Jupiter completely disappeared from the System, the sole effect might be that Earth would get a circular orbit. A 10% mass decrease would not have any significant effects (White, 2007).

Thus, although it sounds rather extreme, the stellification process, if done the right way, would not affect our planet. As for Mars, this would be the fastest and most inexpensive way imagined so far for triggering the greenhouse effect and warming the red planet. In less than one century, Mars might have a thick atmosphere, earthlike temperatures and a hydrosphere supporting the growth and proliferation of terrestrial microorganisms. However, it should be noted that this stage (called ecopoiesis) is just the first step of terraformation.

Atmospheric conversion through photosynthesis and the implementation of more and more complex ecosystems are required in order to make the planet habitable for humans, and these would take centuries or even millennia. There are also long-term problems that need to be solved in the future, the most important being the lack of a planetary magnetosphere. This causes the martian atmosphere to be slowly eroded and pushed into space by the solar wind, and although the erosion operates at a very slow rate (hundreds of millions of years), in the far future it could turn Mars into an inhospitable planet again (McKay et al., 1991, Graham, 2004, Graham, 2006, McKay, 2007). As an additional effect of stellifying the two gas giants, mankind could begin considering the colonization of the largest Jovian and Saturnian satellites.

From safety and technical reasons, the first stellification test should be effectuated on Saturn: the distance from Earth is greater plus the fact that the warhead could be detonated at a larger depth.

5. Costs

The Cassini-Huygens mission had an overall estimated cost of around $3.27 billion U.S.. This included $1.422 billion for pre-launch development, $710 million for mission operations, $54 million for tracking and $422 million for the launch vehicle (Jet Propulsion Laboratory 2009).

A spacecraft that would be used for stellifying Saturn would certainly be much cheaper. Most of the sum above was due to the cost of the Huygens probe and various scientific instruments (spectrometers, magnetometers, imaging systems etc.). The mission proposed here would certainly cost less than $1.5 billion.

What about the charge carried? Well, it should be free. According to the recent Russian - U.S. treaty concerning strategic nuclear arsenals (New START Treaty, 2010), hundreds of nuclear warheads are to be disaffected. Considering that the Cassini orbiter had a weight of 2,125 kg (the total weight, including fuel, Huygens probe etc. was 5,712 kg), a similar probe could carry, for example, two 1.2 megaton- B83 bombs, eight to ten 300-475 kiloton-W87 warheads or, at a higher mass, the explosive from one 9 megaton-B53 bomb (Sublette, 2007).

6. Legal aspects

According to the U.N. Outer Space Treaties, the use of nuclear weapons in space is forbidden. The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, Article IV, states that "States Parties to the Treaty undertake not to place in orbit around the Earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner” and that “the establishment of military bases, installations and fortifications, the testing of any type of weapons and the conduct of military manoeuvres on celestial bodies shall be forbidden".

However, the mission proposed here does not involve any weapon (since does not target any human objective, but an uninhabited celestial body), but a non-military explosive. Furthermore, it would not be placed around a terrestrial orbit, stationed in space or installed on another body, but directed and detonated into Saturn’s atmosphere. As the same article states, "The use of any equipment or facility necessary for peaceful exploration of the Moon and other celestial bodies shall also not be prohibited". Of course, such a mission would require international control.

7. Conclusions

The stellification of Jupiter and Saturn would not only allow mankind to terraform and colonize Jovian and Saturnian satellites (like Ganymede, Callisto and Titan), but, used the right way, this would also have a significant effect on Mars. The ejecta produced by the process would add direct heat, reduce the planet’s albedo and produce water vapor, triggering a runaway greenhouse effect that could lead to ecopoiesis, the first step required for terraforming the planet.

There are evidences that such thing could be achieved using thermonuclear detonations. It might work or as well it might not work, but the recent New START Treaty created the opportunity of testing this theory in a rather inexpensive way. The costs are small compared to such a great potential.

Acknowledgements: Special thanks to mr. Jacco van der Worp, M.Sc. who explained me the way to estimate the mass of the ejecta received by a planet from a igniting star, and for providing me with other insights of his theory.