The flight time to the Red Planet is now equal to the period of bearing a child. However, how long to fly to Mars is far from an idle question. The longer, the more expensive and more dangerous. Therefore, SpaceX intends to cut the flight duration in half.
The distance between Mars and Earth is constantly changing. When the Earth is between the Sun and the Red Planet, it is about 55 million kilometers, and when the Sun lies between us and Mars, it is more than 350 million kilometers. This is what determines how long to fly to Mars. To get to the Red Planet, the easiest way to start is by waiting for the minimum distance, which happens every 26 months. The least energy-consuming Goman's trajectory will take us there in 9 months. The additional acceleration required for it from the earth's orbit is 2.9 kilometers per second. This is the best option for automata, and their flight time is now close to Goman's. For example, "Curiosity" flew there from November 26, 2011 to August 6, 2012.
Homan's trajectory - essentially flying in a spiral, not in a straight line.
What is good for a machine gun is death for a person. During the Curiosity flight, the instruments recorded ionizing radiation (radiation), which for a person would give 0.66 sievert per year (0.5 sievert for 9 "Homan's" months). The norm for cosmonauts is exactly 0.5 sievert per year. An economical trajectory is not suitable, because after "captured" 0.5 sievert in space, a person will have to receive another 0.23 sievert per year on the surface of Mars. Therefore, most projects offer different versions of the hyperbolic trajectory, in which the travel time is six months. Then a trip there will give only 0.33 sievert, another 0.23 - a year on Mars (waiting for a "window" to return), another 0.33 - the way back. In total - about 0.45 sievert per year - "what the doctor ordered."
The hyperbolic path is shown in blue.
So far, projects of this kind all over the world do not go beyond declarations of intent. Nobody tests engines or other elements of rockets for such flights. Nobody - except, of course, one player. SpaceX has already tested the Raptor oxygen-methane engine for the Big Falcon Rocket (BFR) for reusable operation, as well as the fuel tank for it. The BFR trajectory is the shortest nearly straight line ever offered. However, it requires that the second stage of the BFR - a spacecraft for dozens of astronauts is integrated into it - after entering orbit should additionally accelerate by 6 kilometers per second. Energy is proportional to the square of the speed. Therefore, the fuel consumption in this version is 4.3 times higher than for the path to Mars, as in Curiosity. But the travel time is about 115 days.
The SpaceX option may seem too costly, but it really isn't. For acceleration from earth orbit, the fuel for the BFR will be delivered by a tanker ship. But if the BFR had chosen a longer route of 180 days, it would have had to take more food supplies and have more cabins. Man, although lighter than a rover ten times (Curiosity weighed almost 900 kilograms), requires food and free space for exercise. Without them, after landing, he will not be able to move around the planet. And meat is difficult to grow in a ship's greenhouse, so supplies are needed. Food and water are the main cargoes delivered to the ISS. And if the fuel for the fast trajectory of the BFR can be taken from a tanker ship, then it is too expensive to drive food in a separate truck to Mars.
SpaceX's flight scheme has the best chance of being realized in the 2020s. Recently, the Vice President of the United States announced that the States are planning to land on the Moon and Mars, relying on private astronautics. Except for SpaceX, none of the private traders is testing technology to reach such distant celestial bodies.
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There is another, in theory, the fastest way to get to Mars. It was proposed in the USSR back in the 1960s, and is still being developed in Russia in a semi-frozen mode. This is the so-called nuclear tug. A nuclear reactor with a capacity of up to 15 megawatts would power electric rocket engines that eject gas at speeds up to tens of kilometers per second - ten times faster than rockets eject chemical fuel.
Due to this, the flight to Mars would go not only along the shortest trajectory, but also faster than on any rocket - in just 45 days. However, there is a nuance - the development of a tugboat requires several billion dollars, only several times less than for the 2014 Olympics. Funding for domestic space is too small, so there is no chance of project implementation yet.
The US government is not developing a nuclear tug. Recently, there have been reports that SpaceX is trying to acquire nuclear materials for similar purposes. However, even here the success is questionable. The resources of a small private company are too small to handle both the BFR and the nuclear tug. While Elon Musk's missiles have already captured the world market for commercial launches, the company's experience in the nuclear field is still zero.
ALEXANDER BEREZIN
