Die on Mars

In that moment, Tang Yue seemed to have returned to the era of Yuri Gagarin and Alan Shepard a hundred years ago. Engineers tried their best to build a launch pad of hundreds of tons, using nearly 30 The R-7 and Redstone rockets weighing 100,000 tons are just to send the 70 kilograms of payload into space.

This is a huge asymmetry in mathematics and physics. Such huge resources are ultimately aggregated in a small individual.

A long time has passed. People have the ability to build space stations, land on the moon, and go to Mars. They have forgotten the cautiousness and step-by-step approach. The earliest liquid oxygen alcohol engine has a low-Earth orbit carrying capacity of less than three tons. The earliest The manned spacecraft is only two meters long.

But this is the beginning of human spaceflight.

When the old cat said resolutely, "We only need this fraction," the time went back in an instant, back to the moment when Korolev said "no spacesuit" on Voskhod-1, and back to the time when von... The moment Braun said "countdown begins," engineers spent tons and tons of scratch paper, calculating the weight gram by gram, just for that small fraction.

The glory of human spaceflight was gained step by step from this small fraction.

"It's not just the Eagle spacecraft that's going to enter the atmosphere, but also Orion, right?" Tang Yue asked.

"Yes." The old cat nodded, "Orion is the lifeboat, the Aquarius of Apollo 13."

Orion 2 geothermal transfer spacecraft.

One of the largest spacecrafts ever built by mankind. The reason why I add this "one" is because Orion 1 is as large as it. They are not so much spaceships as they are powered space stations. In order to provide enough living space for the six-person crew and store enough supplies and living resources, the configuration of the Orion spacecraft is completely different from conventional spacecrafts.

Its main body is a three-section truss, eighty-eight meters long.

At the front end of the truss is a 60-meter-wide solar panel, eight in total, which are power and energy modules.

In the middle are the command module and the living module. There are eight cabins in total, which are connected in sequence and installed around the main truss. This is the central module.

At the end of the truss is a huge propellant tank and nine Raptor 10D liquid oxygen methane high-pressure supplementary combustion engines. The propellant tank can be filled multiple times and the engine can be reused. This is the power module.

In terms of design, the Orion spacecraft is a rather fragile structure. It is just three candied haws strung on a thin stick and cannot enter the gravity circle of the Earth or Mars. Once affected by gravity, the main truss will undoubtedly be unable to bear the weight of the passenger compartment and engine, and will immediately twist and break.

The day it enters the atmosphere is when it is scrapped and retired.

The Orion spacecraft was born in space and returned to Earth.

"You want Orion to take the Eagle spacecraft into the atmosphere?" Tang Yue asked, "Is... is this possible?"

As a person who knows a little bit about aerospace engineering, Tang Yue feels that this idea is too crazy and there are too many problems that cannot be solved.

Intuitively, the Orion spacecraft will inevitably disintegrate, burn and explode while falling at high speed.

"Sometimes..." The old cat waved his paws, "Technology is the craziest thing."

·

·

·

"The length of the Orion 2 spacecraft is eighty-eight meters, which is the length of its main truss." The old cat held its pen and began to explain the plan to the two of them, "If we..."

"Throw it down." Maidong and Tang Yue both knew what the cat was going to say next.

"...Yes, if we throw it down into the atmosphere, it will 100% disintegrate and crash." The old cat held the pen and placed it across the table. "It can't come down like this, but if we change its direction..."

The old cat raised the pen in its paw.

"If you let it come down like this, it will be possible to ensure the integrity of the structure. This is determined by the material and structure of the truss. Its load-bearing capacity in the vertical direction is five to six times that of the horizontal direction. During the landing process, it is in Slow down, the force on the truss is squeezing rather than stretching... As long as we keep it vertical during the landing process, then it can be inserted firmly to the bottom!"

"But how do we keep it vertical?" Tang Yue asked. He couldn't imagine how to keep an eighty-meter-long thin stick upright in the sky.

"Korolev's Cross!" the old cat replied, "or, imitate Korolev's Cross!"

Korolev Cross? Tang Yue frowned. He vaguely remembered that this word was describing the alliance rocket's release of boosters.

"We have nine Raptor 10D engines and nine swinging nozzles. Each engine has enough thrust." Lao Mao explained. "Putting this stick up in the sky is actually not as difficult as you think. The Orion spacecraft The total weight is 409 tons, of which 329 tons are propellant and engine, which means its center of gravity is at the bottom - because the engine is facing down when landing."

"As long as the four engines maintain thrust in four directions, then this stick will stand steadily in the air." Old Mao put the pen in his hand on the tip of his paw, "Heavy at the bottom and light at the top, with a low center of gravity, so that it can remain stable. , similar technology is actually very mature in reusable rockets. Of course, it cannot receive any lateral thrust during this process. This is also due to the lack of atmosphere on Mars. This cannot be done on Earth. If there is a strong crosswind, it will definitely be over. .”

"Where's the heat...heat barrier?" Maidong asked.

"You don't need to think about the thermal barrier, silly girl." Tang Yue held his chin and pondered for a few seconds, "This cat needs to push back the whole way to land and control the falling speed, but is the propellant on Orion enough?"

"Bingo! This is the key point." Old Cat snapped his fingers. "Propellant is the key to the entire plan. We have a total of nine Raptor 10D engines. There are still 300 tons of fuel in the Orion's propellant tank. If it is propelled If the dose is not enough, everything will be in vain, so we can settle the account."

Maidong and Tang Yue nodded.

The hope lies in Lao Mao’s account.

"The vacuum thrust of a Raptor 10D engine is 900 kilonewtons, which is 90 tons. The total thrust of the nine engines exceeds 800 tons." Lao Mao said, "The average speed of a Raptor engine consuming fuel is 100 tons per second. 60 gallons, converted to metric units is 227 liters, and the total mass of 227 liters of liquid methane and liquid oxygen is 202 kilograms."

Old Mao pointed to the sky above his head, "In other words, the engine of that spacecraft, a Raptor 10 rocket, will burn two hundred kilograms of propellant in one second, and we have a total of three hundred tons of propellant. For consumption, with nine engines running at the same time, how long will this much propellant be enough to last?”

"One hundred and sixty-five seconds." Maidong immediately gave the answer, "Less than three minutes."

Tang Yue was shocked.

One hundred and sixty-five seconds is definitely not enough time.

To land safely from an orbit of 125 kilometers, 165 seconds is absolutely not enough.

"This time is obviously not enough." Lao Mao said, "The spacecraft will run out of fuel at an altitude of tens of thousands of meters, and then fall down and crash."

"What should we do?" Tang Yue asked, "You said there was hope."

"We would like to thank the designers of the Raptor 10D engine. The thrust of one engine is 90 tons, and it can support the landing of a 400-ton spacecraft. Do we need to turn on all nine engines?" Old Cat smiled.

Tang Yue understood immediately.

The total weight of the spacecraft is 409 tons.

One engine has a thrust of 90 tons, so as long as five engines are used, a total thrust of 450 tons can be produced.

"We can use throttling technology to control the thrust of the engines and only turn on five engines. Then you can do the math." Old Cat said, "How long will the propellant be enough to support it?"

"Two hundred and ninety-seven seconds." Maidong's voice was trembling, "At least two hundred and ninety-seven seconds."

"Yes, at least two hundred and ninety-seven seconds. The real situation should be much larger than this number, because the gravity of Mars is only two-fifths of the Earth, so the weight of the Earth of more than 400 tons of the Orion spacecraft is only 160 tons here. ." Old Cat nodded, "So the propellant consumed by the engine is less than we calculated. In fact, Orion's fuel is enough for twelve minutes."

"In twelve minutes and at an altitude of 125 kilometers, we were able to control the average landing speed of the spacecraft to 173 meters per second, which is less than Mach 1."

Tang Yue was stunned.

Ophiopogon's eyes began to turn red.

"Maybe you can come down." The old cat turned his head, shook his ears towards Maidong on the screen, and chuckled, "Miss Maidong."