Jing Jing:
Hope everything is going well with you.
I returned to Jing City a month ago and found some chat history in an old computer. You asked me a lot of questions, but I was very rude and hateful at the time. So I now want to ask, it has been a long time; are you still willing to listen to my reply?
Your first question was about the first cosmic velocity, which is known as orbital velocity.
If I remember correctly, the three cosmic velocities should have been covered in the content for senior high school physics. Did you not listen attentively when you were attending class?
There was a small mistake in the question you asked…
Qiao Jing Jing sat curled up on the sofa in the living room, a glass of red wine by her hand. Reading to this point here, she paused for a while.
It turned out that at the time, there was a mistake in the question that she asked? So that's why when he saw the question, he did not bother to respond and just suggested that she go to Baidu directly?
She was lost in thought for a moment, then bowed her head and continued reading.
There was a small mistake in the question you asked. I suspect you've confused the concept of launch speed and satellization velocity. To be able to elaborate clearly, let's start with the definition of the first cosmic velocity.
Next, the letter explained in detail what is the first cosmic velocity, described the principle and formula of calculation, and even drew a schematic diagram of the orbit and tirelessly expounded on the derivation process.
Qiao Jing Jing used to be pretty good at physics when she was in senior high school, but she had completely long forgotten everything. However, reading through, surprisingly she had no problems understanding what he was saying, probably because what he wrote was thorough and detailed, making it easy to understand.
Even through the paper, she could feel the infinite patience of the person writing the letter.
She put down the letter. Only after a while did she pick up another one.
The beginning was still —
Jing Jing:
Hope everything is going well with you.
I suddenly have some free time this afternoon, so today's letter will probably be a bit longer. Earlier, we already finished talking about the history and current situation of aerospace development in Germany and the United States. In this letter, we'll discuss the former Soviet Union, this country that is closely linked to our country's aerospace development.
Qiao Jing Jing frowned. Wasn't the previous letter about the first cosmic velocity? How did it become one about the history of German and American aerospace development?
She picked up all the letters on the coffee table and looked through them. Only then did she notice that the bottom right corner was marked with the date of writing. A total of nine letters, the one on first cosmic velocity was the first letter and the one she held just a moment ago was already the third letter.
Going according to chronological order, she picked up the second letter.
Jing Jing:
Hope everything is going well with you.
There was a blizzard in the south today. I switched to walking home today, and along the way, I thought about your questions.
The gap between China's and the US's aerospace technology. Hmm, this question is too broad. I may have to answer you with many letters. In this letter, let's first talk about the history of modern aerospace development…
The clock in the living room slowly ticked past midnight, then one o'clock, two o'clock… Qiao Jing Jing read through one by one. Finally, she read the last page of the last letter.
It is undeniable that we still have a long way to go before we can reach the level of the world's top in the aerospace industry. Sometimes, during chats between colleagues on this, some of my colleagues will feel dejected, and they bluntly say that the difference is at least thirty to forty years.
But a gap of thirty to forty years does not mean that it will take thirty to forty years to close it and overtake. This is also one of the important reasons for the work that my colleagues and I do.
We've finished the comparison between the rocket and the manned aerospace flight. We can talk about some aspects of deep space exploration tomorrow. This is my area of specialization. The Voyager and our Yutu both have a very romantic story. But with the speed of the postal service, I figure that you will not receive it before Chinese New Year.
In these several letters, Yu Tu's handwriting at the beginning was always neat and proper, as if the person who wrote the letter was being patient and trying to make his explanations a little clearer. However, as he wrote and wrote, in the later parts, some of his true character started to show and the handwriting became smoother, unconstrained, and a little illegible. By this section, the pen's strokes were free and kept pace with his thoughts, strong and clearly revealing its writer's abilities.
But, at the end of the letter, the handwriting of the last sentence became neat and careful again, as if the person who wrote the letter finished writing all the previous words, stopped for a while, and carefully considered for a very long time before putting pen to paper again——
Jing Jing, are you going back to Jing City during the Spring Festival?