In a broad sense, spacecraft fuel is divided into two parts, one is fuel, Xiao Yu uses liquid hydrogen, and the other part is oxidizer, Xiao Yu uses liquid oxygen.

Fuel must be oxidized in order to burn and generate power. Now, there is not much fuel left on the ship, but there is still a lot of oxidizer left.

In this case, if Xiao Yu can control the spacecraft to reach Titan, the almost infinite methane on Titan can replace liquid hydrogen as Xiao Yu's energy consumption at this stage, and after the development of a controllable nuclear fusion device, Saturn next to it is an inexhaustible source of nuclear fusion fuel.

At that time, Xiao Yu will have the energy to repair the spaceship, the energy to turn on the power at full power and restore the powerful computing power, and even the energy to mine minerals, make new equipment, and new spaceships!

The reality made Xiao Yu sigh incomparably. Titan was there, but Xiao Yu couldn't reach it. The infinite energy is there, but Xiao Yu can't go because of the lack of energy.

"Liquid hydrogen, liquid hydrogen, I want liquid hydrogen!" Xiao Yu almost roared in frustration.

In fact, if you scavenge it again, Xiao Yu's remaining fuel can barely support the escape velocity of Mars and leave the orbit of Mars. But in that case, the remaining energy will only last nine months for a central computer.

Nine months may seem like a long time, but compared to a long space voyage, it is really fleeting.

Even if Xiao Yu recklessly escaped the gravitational field of Mars with the remaining energy, Xiao Yu's maximum sailing speed could only reach six kilometers per second, and at such a speed, it would take about seven years to reach Titan. In other words, Xiao Yu died halfway through.

Such a result is unacceptable to Xiao Yu.

Xiao Yu began to calculate carefully, trying to figure out another method.

"If I don't fly directly towards Titan, but in the direction of the Sun first, with the help of Venus, the gravitational acceleration of the Sun, I can reach a speed of about eight kilometers per second, and the closer I get to the Sun, the faster I will go, so that I will only need about two months to reach the Earth's orbit. Kindness? By the way, there are many comets in the asteroid belt of the Earth, and a lot of water has been evaporated, so if I can collect some water, I can use the ionization of the sun to ionize water into oxygen and hydrogen! I'm back to energy! ”

Xiao Yu's spirit was shocked, and in the midst of the gloom, Xiao Yu finally saw a little hope for life.

"When you're close to the sun, you can reach speeds of up to 26 kilometers per second...... Then orbit the Sun and continue to accelerate with the help of Mercury's gravity, Venus orbits exactly the other side of the Sun, it is not Venus, and then Mars gravitational ...... Jupiter counts, I have to stay away from Jupiter, but even if it passes by Jupiter tens of millions of kilometers away, Jupiter can accelerate me by at least three or four kilometers per second...... In that case......"

Xiao Yu pondered carefully, and his heart became more and more excited.

"If I fly in the direction of the Sun, go around the Sun and then go to Saturn, although the distance has increased from about 1.3 billion kilometers directly to Saturn to about 1.9 billion kilometers, my speed has increased! Save at least five years or more! Moreover, on Earth, I can get liquid oxygen and liquid hydrogen, and if I am close to the sun, I can get a lot of solar energy, so the fuel is replenished! ”

"There's just one thing that's very worrying." Xiao Yu silently calculated, "The earth's orbit is chaotic now, and I have to guard against being attacked by a meteorite." And the Sun, which is definitely also under the influence of Jupiter, and the strength of the solar wind is estimated to be several levels stronger, which is also a potential danger. ”

"Forget it, when you reach the Earth's orbit, let's leave the ecliptic plane temporarily, collect a little less water, and put safety first. As for the sun, it still doesn't cross the orbit of Mercury. Although the acceleration function will be a little less, the safety factor is much greater, and the test of the insulation layer is much less. ”

"Okay, that's it!" Xiao Yu made up his mind, and after Zuihou checked himself and made sure that the entire Jihua would not have too many loopholes, he gritted his teeth and started the spaceship engine.

It's a gamble. Who knows what dangers lie ahead? However, if you continue to gamble, there is still about 30% hope of survival, and if you don't gamble, you will sit back and wait for death. Xiao Yu is really unwilling to get a breakthrough in controlled nuclear fusion, and Mei Haode will die like this when the future is waiting for him. I can't say it, I have to fight anyway.

There are really too many downsides. Not to mention whether there will be new failures in the equipment during the long journey, not whether it will be attacked by a meteorite, whether it can collect a sufficient amount of water, just talk about the thermal insulation layer of the spacecraft, when the spacecraft was originally designed, the thermal insulation layer was designed to deal with the friction of the atmosphere when landing on the planet, not to cope with the high temperature of the sun.

But in such a situation, there is only a duck to the shelf, and if it doesn't work, it will be done, and if you continue to fight, at least it is a hope of life. Xiao Yu was not willing to let his coincidence take a thousand difficulties to fuse his soul with the central computer, and finally obtained infinite life, incomparably powerful computing power and unlimited energy, but he died before his interstellar travel began.

Looking at Mars gradually moving away, Xiao Yu said silently in his heart: "Big brother Mars, thank you for blocking such a powerful wind and rain for your little brother. When the little brother develops science and technology in the future, he will definitely come back to help you transform it, well, transform it into a green planet, and then release some animals on it to transform you into a fairyland on earth. ”

Silently making a wish, Xiao Yu resolutely closed the telescope. In this case, if you can save a little, you can save a little energy.

Immediately afterwards, Xiao Yu turned off most of the non-essential functions of the main control computer, leaving only a few necessary systems such as the navigation system and the radar anti-collision system, and began a bleak long journey.

Now Mars is about 80 million kilometers away from the Earth's orbit, and Xiao Yu will be able to get close to the Earth's orbit in two months. carried out such a long distance roaming, but it turned out to be back to the original point, which made Xiao Yu depressed.

There is also the question of relative velocity. For example, while Xiao Yu orbiting Mars, he is also orbiting the sun with Mars, and his speed is about 25 kilometers per second. When Xiao Yu left Mars and flew towards the sun, from Mars, Xiao Yu flew out in a straight line along the tangent of the orbit, but from the position of the sun, Xiao Yu flew over along a parabolic curve. In short, Xiao Yu's speed close to the sun is about eight kilometers per second, and then it will gradually accelerate under the action of the sun's gravity, and finally it will take about two months to reach the earth's orbit.

Except for the robot on board the spacecraft to start doing some necessary preparations to collect water, the rest of the energy consumption has been minimized, and Xiao Yu can't even calculate the data obtained from Jupiter. Depressed, in addition to separating a few tenths of a CPU usage for the robot, Xiao Yu looked at the dark cosmic space in a daze all day long.

Without the obstruction of the atmosphere, the starry sky is crystal clear. Xiao Yu found the trace of Tianyuan Four among the countless stars.

Celestial Yuan IV is the closest star to the Sun that has been identified as having a planet, about 1.5 light-years away. Tianyuan IV is also the next destination in Xiao Yu's space voyage. Because Tianyuan 4 has been determined to have a gas giant with about 1.5 times the mass of Jupiter, which can provide Xiao Yu with sufficient nuclear fusion fuel, there are also two asteroid belts around Tianyuan 4, which can provide Xiao Yu with sufficient building materials.

"Tianyuan Four. Mankind's first interstellar voyage. Xiao Yu stared at the figure of Tianyuan Si, muttering to himself in his heart, and couldn't help but begin to imagine what it would be like after arriving at Tianyuan Si Star System.

After looking at it for a long time, Xiao Yu retracted his thoughts and sighed sadly: "If this trip to the sun doesn't go well, let alone going to the Tianyuan Four Galaxy, even whether I can survive is a question." ”

More than a month has passed during the long voyage. The meteorite blocks in interstellar space began to increase significantly.

The current trajectory of the spacecraft has left the ecliptic plane. The orbits of the planets basically fall within the ecliptic plane, and even if the earth explodes, most of the earth's debris is also on the ecliptic plane.

When you leave the ecliptic plane, the chances of encountering danger are minimized.

In the past month or so, Xiao Yu controlled the robot and used the remaining materials to make a simple filter to collect ice particles, dust and other materials in interstellar space.

Because of the principle of conservation of angular momentum, even if the Earth explodes, most of its debris will follow its original orbit around the Sun without much change in velocity. These days, Xiao Yu has deliberately manipulated his trajectory to move closer to the original earth's trajectory, so the relative speed of movement between Xiao Yu and these ice particles and dust is not fast, only about one or two hundred meters per second, relying on the strength of this filter, it is enough to capture them little by little.

But the result made Xiao Yu can't help but sigh in his heart.

Twenty-four hours have passed since the filter opened. However, the total mass of the captured material is less than one kilogram. Of these, water accounts for less than 30 per cent.

"Mosquito legs are small and meat, so take your time." While controlling his orbit to move closer to the earth's orbit, Xiao Yu took on the work of a cosmic scavenger.