Tang Yue unbuckled his seatbelt, put the photo frame on the console into his pocket, and jumped out of the Mars Wanderer's cockpit. Old Cat held his hand in the dark. In the current weather, they could not afford to lose each other. However, Old Cat and Tang Yue did not have a safety rope this time. Without a rope to tie them together, Old Cat could only hold on tightly to Tang Yue.
Old Cat held a small emergency light in its paw and waved it in front of Tang Yue. "Follow me closely!
Tang Yue, can you hear me? "
Although the man and cat were very close to each other, the quality of the radio communication was still terrible. A large amount of electrified dust suspended in the air seriously interfered with the radio signal.
"I can hear you." Tang Yue nodded. "It's very clear!"
"We are the last 3.5 kilometers away from our destination. It's in that direction … We need to walk straight in that direction for 3,500 meters." Old Cat extended its paw and pointed forward. "How's your situation?
How's the Bright Light Armour?
How much oxygen and electricity do you have left? "
"I'm fine. I had a full breakfast and I'm full of energy."
Tang Yue brushed away the sand and dust on the Bright Light Armour's control terminal. The terminal screen emitted a faint blue light. "The Bright Light Armour's internal air pressure is normal. The emergency oxygen system can operate for at least ten more hours. The EVA battery can last for six more hours."
"Okay."
Old Cat nodded. "I'll walk in front. You follow behind me and put your hands on my shoulders."
Tang Yue put his hands on Old Cat's shoulders. He followed every step the Old Cat took. When the Old Cat took a step, he followed. When the Old Cat took a step with his left foot, he followed. When the Old Cat took a step with his right foot, he followed. He was like an old zombie from the Qing Dynasty.
Walking 3,500 meters in six hours was a piece of cake for Tang Yue under normal circumstances. He could complete the entire journey in six hours even if he hopped on one foot.
But in a sandstorm, the situation was much more complicated.
To them, the distance was secondary. The biggest problem was figuring out the direction. If they got lost, the time they spent in the sandstorm would be greatly extended.
"Humans can't walk in a strict straight line, so you have to use your vision to correct your direction. In the dark, where you can't see anything, you will walk in circles."
Old Cat said, "Most of the time, you think you're walking in a straight line, but in fact, you've unknowingly deviated from the right direction."
"Coriolis shift?"
Tang Yue lowered his head and closed his eyes as he inched forward step by step. His small, stumbling steps resembled that of an Emperor penguin. Since he could not see anything, Tang Yue decided to just close his eyes and let the Old Cat guide him. He was like a blind man and his guide dog.
"Geodesic force is one of the reasons. The main reason is that you can't guarantee that the strides of your left and right legs are exactly the same."
Old Cat was wearing an IVA suit. He walked with the same caution. There was no light, and the night vision device was useless. Old Cat could only feel his way forward. "Most people's right leg is slightly stronger than their left leg, so the strides of their right leg are larger than those of their left leg. This difference is very small. You can't even notice it normally, but when you're trekking in the desert, this small difference will cause you to unknowingly deviate to the left and eventually return to your original position."
"In other words, your left and right strides are equal?" Tang Yue asked.
"Yes," Old Cat replied. "They're both strictly and constantly 0.4 meters."
"Your legs are so short."
Old Cat led Tang Yue forward. There was a thick layer of floating sand on the ground that could probably cover Tang Yue's ankles. Tang Yue turned his head again, but he could no longer see the Mars Wanderer. The old dog had disappeared into the darkness. Tang Yue knew that he might never see it again in this life.
Tang Yue squeezed Old Cat's shoulder hard. He could not see the Old Cat's back, but he could see the light in his hand. The latter raised the small emergency light above his head. It was the only light in the storm.
Tomcat suddenly came to a halt.
Tang Yue stopped as well. "What's wrong?"
"I have to make sure that I'm not going in the right direction."
Old Cat stood in the same place. "I'm blind like you. If I keep walking, I'll end up at the South Pole."
"But you have a map in your head."
"A map also needs a reference point to be useful." Old Cat slowly bent down and grabbed a handful of sand. "Tang Yue, have you noticed?
The sand under our feet is getting thicker. "
Tang Yue squatted down. The sand that was originally only up to his ankles had now reached his calves.
"What does this mean?"
"It means that we're leaving the Isidis Planum," Old Cat replied. "The landscape has changed significantly."
"Does this mean that we're going in the right direction?"
"No, no matter which direction we go, we're leaving the Isidis Planum … Okay, we can keep going. I've figured out my position." Old Cat straightened up and reported a string of numbers. "130. 8,158.4."
“130.8？
158.4？
What the hell is that? "
"Our position in the coordinate system. I used the Mars Wanderer's parking spot as the origin to construct a polar coordinate system and a Cartesian coordinate system. I just told you that my stride length is strictly 0.4 meters, so every step I take is 0.4 meters."
Old Cat explained, "From the start until now, I've taken 512 steps and advanced a total of 204 meters."
"So where is our target?"
"Its position is probably at (2498. 2,2506. 6)."
"Is it accurate?"
"It can only be as accurate as possible." Old Cat shrugged. "Inertial navigation will always accumulate errors."
Every five minutes, Old Cat had to stop to determine the direction. In theory, the same stride length could ensure that it was walking in a straight line, but reality was more complicated than theory. The uneven terrain and obstacles sometimes forced Old Cat to take a detour.
Tang Yue also learned to count his steps. He closed his eyes and followed Old Cat closely. Every time he took a step, he would silently count it in his heart, but every time he counted to a certain number, he would be interrupted. It could be a rock or a ravine. At this time, Old Cat would turn its head to remind him and then find a way to cross the obstacle. When Tang Yue finished counting, he couldn't remember how many steps he had taken.
In the dark world without light, Tang Yue couldn't feel that he was moving forward. He couldn't count how many steps he had taken before Tang Yue lost his sense of distance.
"Are you tired?"
"I'm okay." Tang Yue panted. "How far have we walked?"
"Six hundred meters."
"Only six hundred meters?" Tang Yue was a little surprised.
"Yes."
"I feel like I've walked as far as six kilometers," Tang Yue said. "That's strange … Why do I feel so tired when I haven't walked that far?"
"Psychological pressure."
Old Cat said, "Normal people will suffer considerable psychological pressure when they completely lose their vision. After all, you're not blind. You won't be able to adapt to this state in a short time."
The sand under their feet was getting thicker and thicker. Both Old Cat and Tang Yue were slipping as they climbed up a tall sand dune. The higher they went, the steeper the slope became. In the end, the man and the cat had to use all four of their feet. Tang Yue grabbed Old Cat's two hind legs and crawled on the sand dune. His four limbs were deeply embedded in the sand.
It was extremely inconvenient to move in the quicksand. He couldn't find a place to exert his strength. Tang Yue tried his best to paddle, but he was still stuck in his original spot. Sand flowed beneath him like a beginner swimming in water. Tomcat's situation wasn't much better than his. It struggled in front of Tang Yue, and after taking three steps forward, it suddenly slipped and returned to its original spot, rolling into Tang Yue's arms.
Tang Yue hugged it as he slumped onto the sand, panting.
"How are you?"
Tang Yue's mask and Old Cat's helmet leaned against each other. He turned on the light inside the Bright Light Armour's mask to illuminate his face. "Did you hurt yourself?"
"I didn't hurt myself. It's just down."
Old Cat said, "Just now, my left arm didn't listen to me. I couldn't use any strength … This arm is going to be useless."
"How's the situation now?"
Tang Yue knew that Old Cat's left arm was an old injury. Along the way, there had been more than one problem, and the symptoms were getting worse and worse.
Old Cat tried to move its limbs. After a few seconds, it shook its head. "I'm afraid it's not very optimistic. The joints of all four limbs are very stiff. We stayed in the storm for too long. Once the temperature drops, the old legs will act up."
"Then, should we take a break?"
"No, the longer we delay, the worse the situation will be. I may need to heat up the body to raise the internal temperature of the body," Old Cat said. "But obviously, we don't have the ability to do that."
It was impossible to heat up the body. What they lacked the most now was energy and electricity. Tang Yue's Bright Light Armour had a thermal insulation function, but Old Cat's IVA suit didn't. The only reason Old Cat wore the IVA suit was to protect it from the wind and sand, and it didn't even have a battery.
Old Cat was silent for a moment. "Listen, Tang Yue, if you have to be alone …"
"Shut up." Tang Yue interrupted it. "I'll teach you how to heat up the body. Do you know how to generate heat by rubbing?
Mechanical energy is converted into internal energy. Yes, it's rubbing your hands. In the winter, we rubbed our hands together to keep warm outside. Old Wang, Old Tang, and the other gays rubbed their hands together to keep warm … You can start rubbing your hands now. Rub!
Rub harder! "
Old Cat was stunned.
"As for the journey, I'll think of a way. Don't think that I'll leave you here …" Tang Yue squatted down and pulled Old Cat's forelimbs around its shoulders and neck. He growled and carried it on his back. Finally, he straightened his body and stood still. "Don't think that I'll leave you here!
Don't even think about it … If you can't walk, I'll carry you! "