Dead on Mars

Chapter 142: Sol Two Hundred and Seventy-Five, We Only Want Sixty Kilograms

“The work that you’ll be doing next will be complicated. I’ll need to explain it to you in detail, Miss Mai Dong.”

Tomcat sat up straight, looking serious.

“Yeah, yeah. I’m listening, Mr. Cat.” Mai Dong floated in front of the camera as she took on the look of an attentive student.

Tang Yue sat to the side at a loss for words. He stared blankly at the pen and paper on the desk, knowing that it was hopeless. Getting the Eagle to return to Kunlun Station was impractical. Regardless if a rocket engine was installed or not, the lander had no means of a successful landing.

The Orion II’s Raptor 10D engines weren’t designed for landing. Even Orion II itself wasn’t capable of atmospheric entry. The massive but weak propellant reservoir tanks attached to it couldn’t withstand much stress, so it was bound to suffer structural meltdown upon atmospheric entry.

As for the thought of dismantling the rocket engine, it was fool’s talk. It was possible with a team with all kinds of cranes. But Mai Dong only had a wrench, so any attempts would appear comedic. Orion’s massive rocket engine nozzles were thicker than Mai Dong’s torso.

Neither he nor Tomcat could give Mai Dong an answer that wasn’t: “It’s hopeless, lady. We can’t do it.”

“We still have hope.”

Tang Yue was taken aback. What?

He turned his head in a bid to confirm that he wasn’t hearing things. What did that cat say? There’s still hope? What hope is there?

It had just completely denied his plan, saying that it was completely unworkable.

Why was it now saying that there was hope again?

“Miss Mai Dong, you should have some basic understanding of a spacecraft’s atmospheric entry. In general, it’s a process of deceleration and landing. Even though the masses like to describe it as something very complicated and dangerous—and of course it is extremely dangerous—it’s essentially a deceleration process,” Tomcat said. “As long as we successfully decelerate, lowering the speed to a sufficiently low speed... all the problems will be solved.”

“Yeah, yeah.”

Tang Yue widened his eyes. Tomcat didn’t seem as though it was joking. Did it really have a solution?

“Deceleration requires power, and only with sufficient power can we very simply and brutally resolve what seems unsolvable.”

“Are you referring to Orion’s engine?” Mai Dong asked.

Tomcat nodded.

“Tang Yue, you just said that dismantling the engines is impractical!” Tang Yue roared. “You said that all your simulations failed. Not a single one of them crossed the ten-thousand-meter altitude!”

“It’s obviously infeasible to dismantle the engines.” Tomcat rolled its eyes. “You’ve seen Orion’s rocket engines, right? Do you think that thing can be dismantled by human strength? You are trapped in a pattern of thinking. It’s true that Miss Mai Dong needs to have the Eagle, but the Eagle isn’t the key... Think about Apollo 13. Was the command module the one that saved everyone’s lives?”

Apollo 13?

Tang Yue was taken aback as his scalp tingled.

He had been trapped in a blind spot. Because the Eagle was a lander, Tang Yue had subconsciously believed that the Eagle was key to everything.

Everything revolved around the Eagle lander, so he had the crazy thoughts of dismantling the engines to install on the lander; thus, having to rack his brains on how stabilize the lander’s attitude.

But the one to really save Mai Dong... had never been the Eagle!

“What we are dismantling isn’t the rocket engines,” Tomcat whispered, “but the Eagle lander and Orion!”

Tang Yue was instantly enlightened. It was a crazy plan, crazier than grappling the lander with the space station. The failure to land successfully was ultimately a lack of thrust. If the thrust was insufficient, more power could be given. If an engine couldn’t satisfy their requirements, they could use all nine!

It was unknown if this train of thought was inherited from the Falcon Heavy or the N1 from years ago.

If it were the former, Tang Yue would still feel a little at ease.

But if it were the latter...

“You said that Orion would be destroyed during an atmospheric entry!” Tang Yue stopped Tomcat.

“That’s right.” Tomcat wore a cold expression. “We want it to be destroyed!”

A robot was a robot after all; it wasn’t humane at all when it went nuts.

Later, Tomcat said, “In human aeronautics, 99% of the problems faced were a result of insufficient power. As long as there was enough power, none of the problems were problems.”

The final 1% was the fault of conventional frameworks.

...

“We all know that if a body is thrown from the sky on Earth, it will be a free-falling body, but it’s not truly a free-falling body.”

“Because of air resistance?” Mai Dong asked.

“Yes, this object will keep accelerating, but it won’t go on forever,” Tomcat said. “At a particular point in its descent, gravity and air resistance will achieve a balance, resulting in terminal velocity.”

Tang Yue and Mai Dong nodded. It was easily comprehensible as it was in high school physics.

“This is influenced by the density of the air, and in physics, there’s a term known as the ballistic coefficient. The Martian atmosphere’s ballistic coefficient is extremely low, which also means that the atmosphere can hardly provide enough resistance to achieve a balance of forces,” Tomcat said. “If we throw a powerless Eagle down, its deceleration will happen extremely slowly. And when its height drops to 40,000 meters, its speed will still exceed Mach 15. The surface temperatures will rise to 2000°C. This is also why we need the heat-resistant tiles.

“In the 20th and early 21st century, many Martian probes perished because of this. The speed was just too fast for them to land successfully.

Tomcat shrugged its shoulders.

What was destroyed in the descent was Martian probes. The most classic example was the European Space Agency’s Beagle 2. The poor lander remained in the desert to this day.

“A lander’s normal descent is this: It enters the atmosphere from an altitude of 125 kilometers. At this time, its speed should be about 5 km/s,” Tomcat used a pen to demonstrate it to the two others. It raised the pen in its paw high before stabbing it down. “85 seconds later, it will inflate an entry device for the first stage of the deceleration. Within that 85 seconds, its altitude will drop to 90 kilometers, enduring the peak heating.

“The entry device will reduce the Eagle’s speed to below Mach 2. This is a Mach number that can withstand the deployment of a parachute. At 10,000 meters, the lander will deploy a parachute with a diameter of thirty meters.” Tomcat spread its paw above the pen to indicate the parachute. “The parachute will reduce the speed of the Eagle to subsonic speeds until the lander reaches a height of 1000 meters. It will then abandon the parachute and activate the rocket engines to change its attitude to begin a powered descent.”

Tomcat slowly placed the pen vertically on the table.

These were things Mai Dong and Tang Yue knew as well. During their training prior to the mission, they had been briefed in detail about the spacecraft’s operational principles.

Tomcat was repeating it again today.

“Why is the process so complicated?” Tomcat asked. “Why does it need to be so complicated?”

Before waiting for their answer, Tomcat answered, “It’s because there’s not enough power. We lack the power from rocket engines to provide a reverse thrust the entire time. Chemical rockets are too inefficient,” Tomcat said. “A rocket’s thrust is mostly pushing itself, with tonnes of its mass being fuel, and the rounding errors are the load.

“In an ordinary descent, it’s not practical to have the rockets produce a reverse thrust the entire time. That will require the Eagle’s cargo and command module to be filled with propellant. The lander will become a flying fuel tank,” Tomcat continued. “But that’s in normal circumstances. What we are going to do is an abnormal descent... We don’t care about efficiency or cost, nor do we care about the hundreds of tonnes of fuel. All we care about is that rounding error!”

Tomcat raised its paw and pointed at Mai Dong, enunciating each and every word: “A rounding error of 60 kilograms!”

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