Reborn in 2011, I am the chief designer of aerospace.

Chapter 90 Returning to Base: Amputation and Survival

The intense mental concentration seemed to have made Song Xingye's senses even more acute.

He could sense Zhang Jingshan and Engineer Chen standing behind him. Zi Guang stared intently at the data he was writing down, his Adam's apple bobbing occasionally, as if he wanted to ask something but was afraid of interrupting his train of thought.

Song Xingye now only needs to verify one thing: tell everyone whether the Forbes is still on its way.

Two hours have passed since the orbital elements were uploaded, and the idle radar resources that Dongguo can currently mobilize are scattered and have not yet tracked the signal.

If, as in the beginning, the Space Force had mobilized all its resources and scanned the sky 24/7 across all frequencies, they should have detected the signal sent back by the Phobos by now.

However, there is still no news about that little thing.

Until now.

A new flight path appeared on the computer screen in front of Song Xingye.

The Forbes currently has a flight cycle of 2 hours, 15 minutes and 36 seconds, and can only circle the Earth a little over ten times a day.

Due to the Earth's rotation, the tracking window for ground-based radar is extremely limited.

But the updated track line at this moment happens to cut into the radar sector of the East Kashi Station!

Therefore, the Forbes will inevitably pass over the city of Khartoum in eastern Asia during its next orbit around the Earth.

A dozen minutes later, the Kashgar tracking and control station delivered a report that was enough to excite everyone: "Kashgar station reports: Target signal successfully acquired, dual acquisition complete!"

"Telemetry signal locked! Target is in good flight condition, orbiting along the predetermined trajectory in a highly elliptical orbit with a perigee of 200 km, an apogee of 5000 km, and an inclination of 55 degrees —"

After a moment of silence, the test team erupted in thunderous cheers and applause.

After searching for nearly eight weeks, they finally found the lost detector and brought it back!

Zhang Jingshan and Engineer Chen also breathed a sigh of relief, patting Song Xingye on the shoulder and giving him a thumbs up.

The two urged Song Xingye to go and rest, but Song Xingye forced himself to stay awake and asked, "So, what's next about the Forbes?"

Engineer Chen smiled and said, "You don't need to worry about the rest; your mission has been perfectly accomplished. As for how to get to Mars—"

I've discussed your proposed "Venus gravity slingshot" scheme with several experts in China, and we all agree that it's worth a try! Go to sleep now and get plenty of rest before returning to the mission.

Having received a definite answer, Song Xingye finally couldn't hold on any longer and went back to his dormitory to sleep.

I slept soundly for a full day and night.

He was eventually woken up by hunger.

He opened his eyes and saw Li Fengxian anxiously guarding the bedside. When he saw that he had woken up, he exclaimed in surprise.

Upon hearing the other person's stomach rumble, Li Fengxian didn't hesitate. He put on his coat, rushed into the snowstorm, and brought back a hot meal from the canteen.

After eating and drinking his fill, Song Xingye let out a satisfied burp, patted his stomach, and asked about the situation on the experimental team's side.

Li Fengxian scratched his head, indicating that he wasn't quite clear about the current situation either.

[At this point, I hope readers will remember our domain name 12199.99]

All he knew was that after the Forbes was successfully recovered, both East and R countries were in an uproar. According to the previous agreement, R country was to assist East country in accelerating Firefly 1 and heading to Venus for a boost. The experts were currently discussing this in the conference room of the telemetry and control center.

Song Xingye nodded, quickly washed his face, put on his down jacket, and braved the wind and snow to rush back to the monitoring and control hall.

As soon as I entered, I happened to see Engineer Chen walking out of the conference room carrying a thick stack of proposals.

"You're awake? How was your rest?" Engineer Chen stopped in his tracks.

"I feel much better."

Engineer Chen hummed in agreement, and without saying another word, shoved the plan in his hand into his arms, saying succinctly, "Country R has confirmed its full assistance. We will discard all the cumbersome payload of the Phobos and use it simply as a launch vehicle to ignite and accelerate the Firefly 1 to Venus, and then use Venus's gravity slingshot to launch it towards Mars."

This is the implementation plan discussed at the meeting. Please take a look.

Song Xingye took the documents handed to him by Engineer Chen and rushed back to his workstation to read them carefully.

The experts were far more efficient than expected, finalizing the implementation details of leveraging Venus's power in such a short time.

I thought it would take a few more days to get a result.

That saves me the trouble of thinking about it.

Take a seat.

Concentrate.

With a thought, Song Xingye activated the [Fault Prediction Eye] instantly.

With keen eyes, he scanned the thick stack of proposals from beginning to end.

Every piece of data and every step is broken down and analyzed in my mind, leaving no stone unturned in addressing any potential risks that could cause the mission to fail.

This plan was developed by Engineer Chen, who brought together a group of leading figures in orbital mechanics, experts from the Lavochkin Design Bureau, and top engineers from the Aerospace Force.

The assembly of the Phobos probe has now been confirmed to have drifted from an elliptical orbit of 200×400 km to a highly elliptical orbit of 200×5000 km.

According to the original plan, it would need to undergo another long-duration ignition to accelerate to the second cosmic velocity of 11.2 km/s before it would be eligible to enter a transfer orbit to Mars.

From a macroscopic perspective, once it reaches the second cosmic velocity, it will soon enter a heliocentric orbit around the sun.

In general terms, it is actually a super elliptical orbit of 200 x 2 million kilometers, except that the apogee of the orbit is near Mars.

Having missed the optimal window for Mars opposition, the Phobos spacecraft, fueled only by its two external fuel tanks, was clearly unable to accelerate.

Telemetry data shows that the combined vehicle is currently traveling at approximately 31,000 kilometers per hour, and the navigation system still has some problems.

Song Xingye read through the page, and the core logic of the solution became clear:

The first thing to do is to send a high-powered command to the Phobos probe, inject new astronomical data, and upload new flight procedures.

The MDU was then ordered to perform a compensatory ignition during its next perigee pass, forcibly correcting the skewed orbital inclination and smoothly entering Venus's transfer orbit.

After making these preparations, the next step for the Forbes is to lighten its load!

After all, this combination weighs 15 tons, with the Phobos probe alone accounting for 13 tons. For a Mars journey where fuel is scarce, this massive body is the biggest burden.

You can not have it both ways.

Between the 13-ton Forbes and the 115-kilogram Firefly 1, the former would naturally be abandoned.

This is a space surgery that involved "cutting off an arm to save a life".

The former is mainly designed for Mars sample return, and the combined weight of the return capsule, parachute, and return fuel accounts for several tons.

It seems this guy has a hard time even getting to Mars, let alone returning.

Therefore, all fuel for the return trip will be ignited in advance.

The return capsule, parachutes, scientific cameras, radar, robotic arms, spectrometers, and anything else that the Phobos could remove and that was structurally feasible to jettison was all cut off and thrown into space!

Finally, only the MDU main thruster, two external fuel tanks, the return capsule fuel tank, the main control computer, the communication antenna, and the Little Firefly 1 probe were retained.

Although small, Yinghuo-1 is fully equipped and can be considered a relatively independent detector in itself.

The ultimate value of the Phobos was to serve as a bare, vacuum-sealed launch vehicle to send Yinghuo-1 to Venus and then, with its momentum, to Mars.

At least, this can preserve the last vestiges of dignity for both countries' space programs, preventing them from ending up with nothing.

It took Song Xingye an entire afternoon to review the contents of the proposal.

It must be said that the experts' abilities are beyond doubt. The "Fault Prediction Eye" gave a green light all the way and did not warn of any obvious errors.

The only fault highlighted in red is the one in the external fuel tank.

Song Xingye rested his chin on his hand, pondered for a while, and tried to figure out which step of the plan had gone wrong.

His gaze darted between the blueprints and data, and after a moment, his expression suddenly sharpened as he instantly grasped the key point.

He didn't even have time for dinner; he immediately went to find Engineer Chen.

"Engineer Chen, I think this part of the plan needs to be adjusted, otherwise it may lead to the accelerated ignition of the Forbes and all previous efforts being wasted."

Engineer Chen was taken aback. He took the plan and looked at the points heavily circled with a ballpoint pen. "Explain in detail. What problems do you see?"

Song Xingye boldly stated, "I think the fuel levels in the two external fuel tanks and the return fuel tank should have some redundancy, so that they won't be completely burned out, whether accelerating or decelerating."

Upon hearing this, Engineer Chen smiled with interest. "Xiao Song, we're going to Venus to borrow power precisely because we're short on fuel. Now you're telling me to keep some as a reserve? Isn't that a contradiction?"

Indeed, according to conventional logic, the two external fuel tanks should be completely emptied and discarded after using the boost.

The return fuel tank will also need to run out of fuel to slow down and capture Mars upon arrival.

This is the ironclad rule of "meticulous attention to detail" in aerospace engineering.

This was certainly to maximize fuel utilization, but Song Xingye put forward a new point of view: "Engineer Chen, I haven't seen the design drawings of the Forbes before, I don't know what those old Russians were thinking."

But you can take a look at the fuel tank structure they designed —

As he spoke, he flipped to the front of the fuel tank diagram and pointed it out to Engineer Chen.

"The thinnest part of the fuel tank skin is only 2 millimeters thick, and even the thickened section in the load-bearing area is only 5 millimeters thick—the materials the Russians used are incredibly cheap!"

Following the direction of his finger, Engineer Chen's brows furrowed into a deep frown.

After a long silence, he said in a deep voice, "According to our country's design standards, the thickened skin area needs to be at least 8 millimeters thick to withstand high-frequency vibrations. This design by the Russians—this isn't just daring and skillful, it's walking a tightrope at the top of a mountain!"

"That's right!" Song Xingye quickly replied, "The skin of this fuel tank is only a little thicker than a coin. To put it bluntly, it's just a thin layer of stainless steel."

He gestured, his tone urgent and serious: "While this design achieves extreme weight reduction, the consequence is—this fuel tank is like a balloon, entirely dependent on the liquid fuel inside to maintain its shape. Once the fuel is drained and the internal pressure disappears, the tank's own weight and external overload will instantly crush it!"

Song Xingye's voice echoed in the office, "Once a crack appears in the weld of the fuel tank, even a leak the size of a pinhole, it will be followed by a space explosion!"

Engineer Chen crossed his arms, his expression grave.

As the head of the test team, he naturally understood immediately.

This is not an exaggeration, but a disaster with a very high probability of happening.

"But----"

Engineer Chen frowned, raising a new dilemma: "According to your logic, the return fuel tank's deceleration reserves also need to be kept in reserve. This would widen the fuel gap even further, and if we can't stop on Mars, the probe will just skim across the Martian surface like a bullet and glide directly into the depths of the solar system—"

If the fuel isn't burned off, there won't be enough deceleration to be captured by Mars' gravity.

This is an endless loop.

However, since Song Xingye dared to bring it up, he must have already been confident in his plan.

Seeing the conflicted look on Engineer Chen's face, he said decisively, "Engineer Chen, there's actually another way to break this vicious cycle. We can achieve deceleration without ignition or jet propulsion!"

Engineer Chen frowned, a puzzled expression on his face: "?"

"Momentum is conserved."

Song Xingye made a startling statement: "When we arrive at Mars and decelerate, we can directly jettison the Phobos probe, allowing Yinghuo-1 to use the momentum to brake and enter Mars orbit on its own!"

A word to awaken the dreamer.

Upon hearing this, Engineer Chen suddenly understood.

This is a concept that is rarely mentioned in aerospace engineering.

And it sounds very counterintuitive about physics—without ignition or jet propulsion, just by throwing away some parts, how can it slow down when the load has been reduced?

However, this can only be done under extremely special conditions.

According to the law of conservation of momentum, if the "discarded mass" gains a huge extra velocity at the moment of separation, then the remaining "parent body" will inevitably gain a reverse impulse.

The greater the mass thrown out, the more obvious the deceleration effect of the mother body.

This requires two stringent prerequisites:

First, reverse separation;

Second, the abandoned parts must have the ability to accelerate proactively.

In other words, that "sacrificial pawn" must come with its own engine!

Engineer Chen's eyes gleamed, and he clapped his hands, exclaiming, "That's right! After separating Firefly 1 from Forbes by explosives, Forbes will be a huge wasteland! Let it activate its MDU, burn all the remaining fuel, and race off in the opposite direction!"

"This way, Firefly 1 can gain a huge reverse thrust to slow down. And even if that thin-walled fuel tank explodes in the end, it won't hit Firefly 1, which has already gone far away. This move—this move is simply a stroke of genius!"

Engineer Chen was beaming with excitement. He slapped Song Xingye hard on the shoulder and praised him repeatedly, "Good lad! No wonder you're a promising talent selected by Xingchen. Your thinking is much sharper than ours, these old guys!"

Song Xingye smiled modestly: "Engineer Chen, you flatter me. I just thought a beat faster than usual."

"Alright, stop being modest. You did a great job. I'll go report to the higher-ups right now, fix the loopholes in the plan, and we'll proceed according to your plan!"

Watching Engineer Chen leave excitedly with the proposal in his arms, Song Xingye breathed a sigh of relief, finally feeling a weight lifted from his heart.

The next step is to wait patiently.

After various departments worked intensively on discussions and simulations, the final process was finally finalized within a week.

The morning of January 10th.

The Forbes combination has entered a new course on a highly elliptical orbit of 200 x 5000 km.