Life on the moons of Jupiter: is it possible and when will people fly there?

What signals are we talking about?

Such signals have been known for a long time: they are called decameter radio bursts.

(decametric radio emission). The word "decameter" means tens of meters, since the wavelength of radio bursts is tens of meters.

After accidentally opening radio bursts withJupiter, scientists have tried to understand what caused this radio emission. They began with careful observations, recording the time they heard Jupiter and how intense Jupiter's decameter radio bursts were. (The word decameter means tens of meters, since the wavelength of radio bursts is tens of meters). After collecting this radio data, they compared it with other information about Jupiter. They began to match Jupiter's radio flares with the planet's rotation. The only way to know which part of Jupiter is facing them at a particular time is to know how fast it rotates. At first, astronomers knew the speed of Jupiter's rotation only by observing the clouds moving across the planet; there are no surface objects to track.

The observers realized that we hear Jupiter or not,largely depends on which part of Jupiter is facing us at the moment. Radio emission depends on the longitude of Jupiter. It looks like there are special longitudes at which Jupiter can be heard much more often than others. These longitudes were like "landmarks" on a planet with no visible surface. These landmarks also mean that Jupiter isn't just emitting radio waves in all directions, but rather radiating radio waves into space.

Why are the new radio bursts so remarkable?

The spacecraft recently recorded for the first timedecameter radio bursts in the immediate vicinity of their origin. In fact, the probe flew through a radio burst source, near Ganymede, Jupiter's largest moon.

Juno's sensors observed the phenomenon for about fiveseconds, and then the radio signal merged with the background radiation. Given the speed of the probe - about 50 km / s - we can conclude that the area of ​​space where the signal is generated is 250 km across.

Notable observation international teamresearchers reported in a new study. The original publication was posted in the peer-reviewed journal Geophysical Research Letters. It gained public attention after a broadcast on KTVX, where NASA representative in Utah Patrick Wiggins spoke.

Talking about the new radio signal receivedthe Jino spacecraft, the NASA representative emphasized that the origin of this signal is natural. Such radio bursts result from cyclotron maser instability (CMI). The essence of this effect is the amplification of radio waves by free electrons. This happens if the frequency of oscillations of electrons in the plasma is significantly lower than their cyclotron frequency. Then even a random signal that has successfully appeared in a cloud of charged particles can become noticeable, Naked Science notes. Radio bursts form in areas of Jupiter's magnetosphere where it closely interacts with Ganymede's magnetic field. Electrons trapped by magnetic lines can not only generate radio waves.

Is life possible on Jupiter and its moons?

In 1610 Galileo Galilei became the firstan astronomer who discovered Jupiter's large moons with a telescope of his own design. Over time, these moons - Io, Europa, Ganymede and Callisto - collectively became known as the "Galilean moons" in honor of their discoverer. And since the beginning of space exploration, what we learned about these satellites has fascinated and inspired scientists too.

Three inner Galilean moons rotate at a 4: 2: 1 resonance

For example, since the Pioneer andVoyager passed through the moon system decades ago, and scientists suspected that satellites like Europa might be the best choice for finding life beyond Earth in the outer solar system. It's all about the presence of water ice, inland oceans, minerals and organic molecules. With the first discoveries about the nature of Jupiter's moons, it was suggested that humanity might one day colonize them.

By the way, the concept of a colonized systemJupiter is featured in many science fiction publications. For example, Robert Heinlein's The Farmer in the Sky (1953) tells the story of a teenage boy and his family moving to Ganymede. In the story, this Jupiter moon is in the process of terraforming and farmers are hired to help turn it into an agricultural colony.

How did scientists propose colonizing Jupiter's moons?

Since the Voyager probes passed throughsystem of Jupiter, astronomers have made several proposals for crewed missions to Jupiter's moons and even for the establishment of settlements there. For example, in 1994 a private space venture known as Project Artemis was created with the goal of colonizing the moon in the 21st century. Now, many years later, this project has come to life again and is actively developing.

"Family portrait" of four Galilean companions(Io Europa, Ganymede and Callisto) around Jupiter, taken by the New Horizons spacecraft and published in 2007. Photo: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute

Later, in 1997, scientists developed plans tocolonization of Europe, which envisaged the creation of an igloo on its surface. It was assumed that later these buildings would serve as a base for scientists. They will be able to "delve" into Europa's ice crust and explore the subsurface ocean. In this regard, the possibility of using "air holes" in the ice cover for long-term residence of people was also discussed.

  • HOPE project

In 2003, NASA prepared a study called Human Outer Planet Exploration (HOPE), which focused onexploration of the future of the solar system. Due to its remoteness from Jupiter and therefore lower levels of solar radiation, the moon Callisto was the target in this study.

The plan called for the start of operations in 2045.First, it is necessary to establish a base on Callisto, where scientific teams can remotely control a robotic submarine. It, in turn, will be used to explore the inner ocean of Europe. These research teams will also be mining surface samples near the Callisto landing site.

Last but not least, the expedition toCallisto will create a reusable surface habitat where water ice can be collected and converted into rocket fuel. Thus, this base could serve as a supply base for all future operational missions in the Jupiter system.

Also in 2003, NASA reported that a manneda mission to Callisto may be possible in the 2040s. According to a joint study published by the Glenn Research Center and the Ohio Aerospace Institute, this mission will be based on a spacecraft equipped with a nuclear electric propulsion system (NPP) and artificial gravity. This ship is to deliver the crew for a five-year mission to establish a base on Callisto.

In his book “Spacewalk: Creation of a Space Civilization " (1999) Robert Zubrin advocated the development of the atmosphere of the outer planets, including Jupiter, to produce helium-3 fuel.

Helium-3 is a stable isotope of helium.The nucleus of helium-3 consists of two protons and one neutron, in contrast to the heavier other stable itosope, helium-4, which contains two protons and two neutrons. Helium-3 is sometimes viewed as a hypothetical thermonuclear fuel. This fuel has many advantages - they include a tenfold lower flux of neutrons from the reaction zone. This sharply reduces the induced radioactivity and the degradation of the structural materials of the reactor. In addition, protons - one of the reaction products - are easily captured, unlike neutrons. They can be used to generate additional electricity. Moreover, both helium-3 and deuterium are inactive by themselves. This means that their storage does not require special precautions, and in the event of a reactor accident with depressurization of the core, the radioactivity of the release is close to zero. However, the helium-deuterium reaction also has a serious drawback - a significantly higher temperature threshold (a temperature of the order of a billion degrees is required to start the reaction).

This will require a base on one orseveral Galilean satellites. NASA also speculated about such a possibility, citing that. that the find will provide an unlimited supply of fuel for fusion reactors here on Earth, and anywhere else in the solar system, where colonies will exist.

Now this isotope is planned to be mined on the Moon for the needs of thermonuclear energy. However, this is a matter of the distant future. Nevertheless, helium-3 is already in great demand today - in particular, in medicine.

  • Lifeboat Foundation

The Lifeboat project was founded in the 2000sFoundation. It is a non-profit organization dedicated to the preservation of humanity. In 2012, they released a study called Colonization of Jupiter's Moons: Assessing Our Possibilities and Alternatives, which looked at the colonization of Galilean satellites as a potential alternative to colonies on the Moon or Mars.

Why colonize the moons of Jupiter?

Colonizing the Galilean moons has many potential benefits for humanity.

First, the Jupiter system is incredibly rich.volatile substances, including water, carbon dioxide and ammonia ice, and organic molecules. In addition, Jupiter's moons are also believed to contain massive amounts of liquid water.

For example, estimates of the volume of the inland ocean of Europeit is believed that it may contain up to three quadrillion cubic kilometers of water. This is slightly more than double the combined volume of all of Earth's oceans. In addition, colonies on Jupiter's moons could allow missions to Jupiter itself, where hydrogen and helium-3 can be produced as nuclear fuel.

Illustrations of Europa (foreground), Jupiter (right), and Io (center) show water plumes reaching the surface. Credit: NASA / JPL - Caltech

Secondly, the colonies based on Europe andGanymede will also be allowed to carry out several exploration missions in the inland oceans that these satellites are believed to have. Given that these oceans are also considered some of the most likely locations for extraterrestrial life in our solar system, the opportunity to explore them up close would be a great opportunity.

Third, colonies on the moons of Io, Europe,Ganymede and Callisto will also facilitate missions further into the solar system. These colonies can serve as stopping points and resupply bases for missions heading to and from the Croian system (Saturn's moon system), where additional resources can be gathered.

In short, colonies in the Jupiter system will provide humankind with access to rich resources and tremendous research opportunities.

Colonization problems

The challenges in mastering Jupiter's moons are also enormous.like the gas giant itself. These include, but are not limited to, radiation, the long-term effects of low gravity, transportation problems, lack of infrastructure, and of course huge costs. Given the danger that radiation poses to exploration, it is advisable to first consider this aspect.

  • Radiation

Io and Europa, being closest to JupiterGalileans receive the most radiation from all of these moons. This is compounded by the fact that they have no protective magnetic field and a very thin atmosphere. Thus, the surface of Io receives an average of about 3,600 rem per day, while Europe receives about 540 rem per day.

100 rem - the lower level of development of a mild degree of radiation sickness;

450 rem - severe radiation sickness (50% of those exposed to death die);

600 - 700 rem and more - a single dose received is considered absolutely lethal.

Jupiter's magnetic field and joint rotation induce currents. Credit: Wikipedia Commons.

By comparison, people here on Earth are exposed toexposure less than 1 rem per day (0.62 for residents of developed countries). Exposure to 500 rem per day can be fatal, and exposure to approximately 75 rem over several days is sufficient to cause serious health problems and radiation poisoning.

Ganymede is the only Galilean moon (andthe only non-gas giant body, except for the Earth), which has a magnetosphere. On average, the moon receives about 8 rad of radiation per day. This is equivalent to the impact on the surface of Mars on average per year.

Only Callisto is far enough from Jupiter. Here, radiation levels reach only 0.01 rem per day. However, its distance from Jupiter means there is no tidal heating of the moon.

Artist's impression of the base by Callisto. Credit: NASA.

Another major problem is long-termthe impact of low gravity on these satellites on human health. On the Galilean satellites, the surface gravity ranges from 0.126 g (for Callisto) to 0.183 g (for Io). This is comparable to the Moon (0.1654 g), but significantly less than Mars (0.376 g). Although the effects of this phenomenon are not fully understood, the long-term effects of microgravity are known to include loss of bone density and muscle degeneration.

  • Distance

Compared to other potential locations forcolonization, the Jupiter system is also very far from Earth. Thus, transporting crews and all the heavy equipment needed to build a colony will take a very long time, as will missions in which resources are delivered to and from Jupiter's moons.

To give you an idea of ​​how long it will take, consider a few real missions to Jupiter. NASA's probe was the first spacecraft to travel from Earth to Jupiter. Pioneer 10, which was launched on March 3, 1972 and reached the Jupiter system on December 3, 1973 - in 640 days (1.75 years) flight time.

Pioneer 11 made the journey in 606 days, but like its predecessor, it just passed through the system on its way to the Outer Planets. Likewise the probes Voyager 1 and 2 that also went through the system took 546 and 688 days, respectively.

Artistic concept of a bimodal nuclear thermal rocket in low earth orbit. Credit: NASA.

In the case of the mission "Galileo" the probe left Earth on October 18, 1989 and arrived at Jupiter on December 7, 1995. In other words, it took 6 years, 1 month and 19 days to get to Jupiter from Earth without flying. "Juno" was launched from Earth on August 5, 2011 and entered orbit around Jupiter on July 5, 2016. The journey took 1796 days, or just under 5 years.

It should be noted that these were missions withoutcrews, which involved only a robotic probe and not a vessel large enough to accommodate people, supplies and heavy equipment. As a result, colonial ships would have to be much larger and heavier. They would require advanced propulsion systems such as nuclear thermal / nuclear electric engines. They must ensure that the journey takes a reasonable time.

For flights to the moons of Jupiter and backbases between Earth and Jupiter will be required to allow refueling and resupply, and to cut costs on individual missions. This would mean that permanent outposts would need to be established on the Moon, Mars and most likely in the asteroid belt before any missions to Jupiter's moons would be deemed feasible or cost-effective.

  • Cost

These last two issues raise the question ofcost. Between building ships that can travel to Jupiter in a fair amount of time, building the bases needed to support them, and the cost of creating the colonies themselves, the colonization of Jupiter's satellites will be incredibly expensive, notes Universe Today.

What's the bottom line?

Considering all the dangers, time and high costone should ask the question, many are asking the question "is it worth it?" On the other hand, in the context of space exploration and colonization, the idea of ​​creating permanent human outposts on Jupiter's moons makes sense. All problems can be solved with the proper precautions and the allocation of the necessary resources. And although he will have to wait until similar colonies / bases are created on the Moon and Mars, this is not bad for the "next step".

Having colonies on any of the Galilean satellites,humanity will have a foothold in the outer solar system, a stopping point for future missions to Saturn and beyond, and access to new resources. Again, it all comes down to how much humanity is willing to spend. A fundamentally new type of fuel can make flying more budgetary. However, it does not exist yet.

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Terraforming - climate changeconditions of a planet, satellite or other space body to bring the atmosphere, temperature and environmental conditions into a state suitable for the habitation of terrestrial animals and plants.

English - hope

Nuclear electric propulsion system (NPP) -propulsion system of a spacecraft, which includes a complex of onboard systems of a spacecraft (SC), such as: an electric rocket engine (ERE), a power supply system provided by a nuclear reactor, a storage and supply system of a working medium (SKHiP), an automatic control system (ACS) ...

Robert Zubrin - American engineer and publicist,founder of the Martian Society. He graduated from the University of Rochester with a bachelor's degree in mathematics, then studied nuclear energy at the University of Washington, defended his dissertation.

Kronos, Cronus in ancient Greek mythology is the supreme deity, according to another opinion titan, the younger son of the first god Uranus (sky) and the goddess-demiurge Gaia (earth).

Initially, the god of agriculture, later, in the Hellenistic period, was identified with the god personifying time, Chronos.

Corresponds to the Roman god Saturn (Saturnus).