Although the stars are very distant from us, the idea of flying to them is one of the most mesmerizing in human history. So far, it remains only an idea, but interest in it does not fall, and every year new ambitious projects for the construction of starships appear. Moreover, some of them may well be implemented in the near future.
GENERATION SHIPS
In the middle of the twentieth century, science fiction writers on the pages of their novels with great enthusiasm engaged in the active exploration of the Galaxy: the so-called "space opera" came into fashion, in which scientific and technical reliability did not matter, which allowed the imagination to be fully revealed. However, even then there were writers who thought that flying to the stars is a rather laborious, dangerous, but, most importantly, a very long business, and the flight itself can take hundreds of years. As a result, the concept of a "ship of generations" appeared - that is, a spaceship-city, in which the crew includes not only adult astronauts, but also their children and grandchildren, who have to complete a long-term mission. By the way, our compatriot, the Soviet writer Vivian Itin, was the first to express the concept of a "ship of generations" in his story "The Country of Gonguri", published in 1922.
In the early 1960s, a certain euphoria reigned in the scientific community due to the spectacular achievements of manned astronautics. Various projects of starships were discussed in mass journals, and in serious monographs, and at international conferences. The most popular at that time was the idea of photon (quantum) rockets, which theoretically could develop subluminal speeds and, due to relativistic effects, reach the stars in a relatively short time for the crew. The problem was that the source of thrust for the photonic rockets was the annihilation of matter with antimatter, and the latter required tens of thousands of tons. Numerous inventors and science fiction writers relied on the imminent appearance of antimatter synthesis technology, but there are still no significant breakthroughs in this matter.and the amount of antimatter obtained is measured not by grams, but by individual atoms.
Later, other original ideas appeared: for example, within the framework of the Orion and Daedalus projects, it was proposed to build starships that would be accelerated by a series of atomic explosions. Both a solar sail and Bassard's ramjet engine were considered as a means of achieving relativistic velocities. Unfortunately, all these options are very expensive and cannot provide a quick solution to the main problem - flight to the nearest star and back during the lifetime of a generation. Therefore, in the early 1980s, the discussion of manned options "froze", and projects of light research probes that are easier to accelerate and which do not need a bulky power supply system came to the fore.
STAR SHOT
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In 1985, the American physicist Robert Forward proposed a conceptual design for the Starwisp probe, which involves the creation of the thinnest mesh sail weighing only 20 grams, accelerated by a 10 Gigawatt narrow-beam microwave beam from a near-Earth satellite. At 115 g, the net sail will reach 20% of light speed for a week. At the grid nodes, Forward was going to place microcircuits with elementary logic and light sensitivity. By the time the probe arrives in the system of the closest star to us, Alpha Centauri, ahead of time, the transmitter in near-earth orbit will turn on again and "flood" the alien world with a stream of microwave energy. Using the wire mesh cells as receiver antennas, the probe's chips will collect this energy and the probe will conduct the necessary research. Then the cells from receiving cells turn into transmitting antennas, and the received information goes to the Earth.
The idea of Robert Forward at that time did not arouse much interest and was forgotten for a long time. Today, famous astrophysicist Stephen Hawking and Russian millionaire Yuri Milner are trying to revive it at a new technical level. On April 12, on the day of the 55th anniversary of the first manned space flight, performed by Yuri Gagarin, they made a presentation of the Starshot project. According to their proposed concept, a swarm of microscopic vehicles (StarChips) weighing several grams, each of which will be equipped with the lightest reflective sail, will go on a flight to Alpha Centauri. The swarm will be dispersed by a huge 100 Gigawatt ground laser built in a high-mountainous region to reduce the possible heating of the atmosphere. As in the Forward project, the swarm is planned to be accelerated to 20% of light speed. Flying through the Alpha Centauri system, microprobes will photograph in detail the planets located there and transmit data to Earth. The sponsors of "Star Shot", joined by the creator of the social network Facebook Mark Zuckerberg, are allocating $ 100 million to work out the technical aspects of the mission.
ROY PROBLEMS
One should not think that the authors of Star Shot do not understand the complexity of the formulated tasks. For example, for normal operation, the StarChip microscopic apparatus must be able to navigate in space, take pictures of selected objects, be protected from destruction by cosmic particles and have its own energy source. Such a technique does not yet exist, or rather, it exists, but it has a solid size and mass, measured in kilograms, not grams. Nevertheless, separate solutions for reducing the mass of probes are being proposed right now: for the orientation system, the authors of the project are going to use low-thrust photon engines; as a source of energy - radioisotope decay or heating of the surface of probes when colliding with interstellar dust; as TV cameras - special semiconductor devices that do not require mirrors,lenses and other moving parts.
The laser system, which will accelerate the StarChip swarm on its way to the stars, also raises big questions. The price of laser amplifiers falls as they are improved and mass production expanded, but in any case, the construction of the installation will require not millions, but tens of billions of dollars. In addition, 100 Gigawatts of energy is four times more than all our nuclear power plants in Russia today provide. Although the public accepted Hawking and Milner's presentation with great interest (of course, we are talking about millions of dollars!), Scientists were skeptical about the idea. In particular, the Russian physicist Boris Evgenievich Stern subjected the project to pejorative criticism. In his article "Two in Physics", he indicates that under the influence of a laser beam of such a high power, the sail temperature will rise to 30,000 K,which will lead to its instant evaporation. In addition, Stern writes, if the laser installation is placed on Earth, even in a high-mountainous region, it will not be possible to focus its beam on a reflective surface several meters in size due to the distortion introduced by the atmosphere. For some reason, the authors of the project have forgotten that the swarm of probes will pass next to an alien star, so the weak streams of data transmitted by microscopic StarChip will be “clogged” with its “noise”. If it turns out to build a receiver capable of separating such a small signal against the background of "noise", then there is no point in launching probes: it itself can serve as an excellent tool for studying the nearest planetary systems.focusing its beam on a reflective surface several meters in size will not work due to the distortion introduced by the atmosphere. For some reason, the authors of the project have forgotten that the swarm of probes will pass next to an alien star, so the weak streams of data transmitted by microscopic StarChip will be “clogged” with its “noise”. If it turns out to build a receiver capable of separating such a small signal against the background of "noise", then there is no point in launching probes: it itself can serve as an excellent tool for studying the nearest planetary systems.focusing its beam on a reflective surface several meters in size will not work due to the distortion introduced by the atmosphere. For some reason, the authors of the project have forgotten that the swarm of probes will pass next to an alien star, so the weak streams of data transmitted by microscopic StarChip will be “clogged” with its “noise”. If it turns out to build a receiver capable of separating such a small signal against the background of "noise", then there is no point in launching probes: it itself can serve as an excellent tool for studying the nearest planetary systems. If it turns out to build a receiver capable of separating such a small signal against the background of "noise", then there is no point in launching probes: it itself can serve as an excellent tool for studying the nearest planetary systems. If it turns out to build a receiver capable of separating such a small signal against the background of "noise", then there is no point in launching probes: it itself can serve as an excellent tool for studying the nearest planetary systems.
Perhaps the skeptics are right, and the Star Shot project is just a PR campaign designed to awaken interest in the topic. However, another option is quite likely: in the course of solving complex technical problems associated with the project, scientists will be able to find a way to create a real interstellar probe that will go on a long journey during our lifetime.
Anton Pervushin