With the science and technology on the modern earth, can anyone travel in space?

Thousands of years later, the speed of human beings on the Apollo spacecraft increased from 4 kilometers per hour to 40 thousand kilometers per hour. However, if we want to reach Alpha Centauri in a few decades, the speed of Apollo spacecraft will have to be increased by 10000 times, which is close to the speed of light. In fact, in order to realize space travel, we need to fly not only faster, but also faster. Despite these seemingly insurmountable difficulties, scientists believe that traveling to planets outside our solar system will come true one day.

The spacecraft must have fuel to have propulsion, and the improvement of spacecraft speed depends on the exponential increase of fuel. If the gas velocity in the exhaust nozzle is 3 times, the fuel required is 20 times the weight of the rest of the rocket (so-called "dry weight"). To be honest, the chemical combustion of hydrogen and oxygen is really too slow. Thermonuclear rockets with fission reactor cores can allow large manned spacecraft to travel in the solar system, provided that the spacecraft can collect and use resources from other places, such as gas giant planets (hydrogen is one of the main components of the atmosphere of gas giant planets). As early as the Cold War, the Soviet Union and the United States began to develop thermonuclear rockets. In fact, thermonuclear rocket is the best vehicle to realize manned travel between planets of the solar system as soon as possible.

Make full preparations for landing, then set up an alien camp, and even implement the earth transformation of aliens. In the process of carrying humans to the target planet, the spacecraft may throw small detectors into the orbits of other planets, which are in the same star-planet system as the target planet. By studying the spectrum from the earth's atmosphere, we can find interesting compounds such as water and methane.

In order to support the survival of creatures from the earth, aliens should not only have liquid water, but also have a breathable atmosphere. We can even reconstruct the evolution of life on earth on other planets, starting with the introduction of microorganisms. In order to thrive in a very hot, cold or chemically dangerous alien environment, we may need to introduce microbes that can tolerate extreme conditions to aliens to produce carbon dioxide.

One thing we can assume is that aliens will be as curious about us as we are about them. What are we in their eyes? Will we be regarded as a threat by them? How will we live on other planets? What will they learn from us? Such an interesting question will not be answered until the day when we really settle in an alien land or meet an alien civilization. And curiosity about these questions is not part of the driving force for us to strive to achieve space travel?