“10 (Ten), 9 (Nine), 8 (Eight), 7 (Seven)…”
The countdown proceeds.
Today, we are launching a research rocket from a launch site hastily erected on the sea. With no useful resources found, Commander (Eve), exasperated, ordered (or rather, begged) ＜Ringo＞, and it was finally decided to allocate some resources to space development.
This newfound leeway is thanks to the increased resources being sent from Fortress Two.
However, if certain results are not achieved, the launch site will be dismantled and used for the construction of a seabed platform.
“Ignition… Thrust at prescribed value. 2 (Two), 1 (One), Lift off.”
The rocket being launched this time is a disposable solid fuel rocket.
It carries research equipment at its tip and accelerates as long as the fuel lasts. If it fails to escape the gravitational sphere, it will fall back to Earth. If it succeeds, it will operate as a simple satellite for a few days.
Since there is almost no propulsion device capable of orbital control, it is expected to eventually fall into the atmosphere and burn out.
“No. 1 is ascending normally. Passing altitude of 5km.”
“Ooh, fast, fast.”
The aircraft is light, and the rocket is a simple launch. The second-stage rocket is also solid fuel, and there are very few devices other than fuel.
“Reaching altitude of 10km. 11, 12…”
The rocket is ascending smoothly. It has already been confirmed from the data of the early warning High-Altitude Plane (Plane) launched in the early stages that it can ascend without problems to an altitude of nearly 20km.
“Altitude of 18km. Discrepancy confirmed between the value of the acceleration sensor and the value measured by radar.”
“…Here it comes.”
A decrease in ascent speed was also observed during the previous rocket launch.
Despite no visible problems, the acceleration is clearly decreasing.
However, this time the rocket is equipped with a precision accelerometer.
Therefore, the problem could be visualized in the form of a discrepancy between the apparent acceleration and the Gravitational Acceleration.
“No abnormalities in the combustion temperature of the rocket motor. No abnormalities in the temperature, pressure, vibration, etc. of the aircraft. Judging from the observation results, there is a possibility that Gravitational Acceleration is increasing.”
“…Huh? …Huh? Eh, does Gravitational Acceleration change?”
“It does not change.”
“It doesn’t, right!?”
No abnormalities are observed in the rocket motor that continues to burn. No problems can be found in observations using various wavelengths of Electromagnetic Waves.
The various internal sensors are not measuring any strange conditions, but the only thing showing an abnormal value is the acceleration sensor. There is no noticeable change in the acceleration at each position inside the aircraft.
Nevertheless, the acceleration calculated by performing radar measurements from the outside is visibly decreasing. In other words, some kind of external force is being generated, and the rocket’s acceleration is being suppressed.
The simple explanation would be air resistance, but it is hard to believe that the atmosphere is becoming denser as the altitude increases.
There is a possibility that the atmospheric composition is changing, but at least when the High-Altitude Plane (Plane) investigated up to an altitude of about 30km, no significant problems were found.
In that case, the only other thing that can be considered is gravity. That is, the Gravity of this planet.
“I had doubts from the beginning. Although this planet has a much larger diameter than Earth, the Gravitational Acceleration is approximately 9.81m/s2, which is almost the same as Earth. Gravitational Acceleration is determined by diameter and mass, but it is too convenient that the decimal places match to 5 digits.”
“…Well, that’s true. The diameter and mass are well-balanced so that the Gravitational Acceleration is the same, right?”
“Yes, Ma’am. However, the probability that it would happen to be the same Gravitational Acceleration as Earth is almost zero. Furthermore, water exists on that planet, life flourishes, and even a human species with almost no genetic differences dominates. Rather than dismissing it as a coincidence, it is more natural to think that there is some kind of manipulation.”
Even during ＜Ringo＞’s explanation, the rocket is increasing its altitude. The speed is not as high as initially planned, and the altitude is not increasing accordingly.
Even so, the rocket has already exceeded an altitude of 60km and is continuing to ascend further.
“The first-stage rocket combustion is complete. Combustion complete. First-stage separation. Second-stage rocket motor, Ignition. …Combustion status is good. Fairing separation. Succeeded.”
＜Ringo＞ carefully observes the rocket’s trajectory. Observation of acceleration after engine shutdown. The atmosphere is thin, and the only external force is Gravity. The value of the accelerometer inside the aircraft, and the speed calculation by radar measurement.
“Ma’am. After all, the Gravitational Acceleration at high altitude seems to be several times greater than on the ground.”
“…Hee. …No, sorry, I don’t understand what you mean.”
The further away from the surface, the greater the Gravity becomes. Of course, this is an unscientific phenomenon.
Logically, the further away you get from a heavy object, the lower the Gravitational Acceleration, that is, gravity, should be.
However, this is within the margin of error at an altitude of about 100km.
“Commander (Onee-chan), um… the calculation is finished… I think, the Gravity is, twice as strong as on the ground…”
“Oh, thank you, Olive. Is that so…? When you go up into the sky, the Gravity becomes twice as strong…?”
“Altitude 120km. Acceleration stabilized. Gravity is approximately twice as strong, and no further increase is observed. Due to the influence of Gravity, the planned speed is not being achieved. Orbital Velocity not reached.”
“U-um…”
Orbital Velocity, to put it simply, defines the speed at which an object, if launched at the appropriate angle, can continue to orbit without returning to the surface. Artificial satellites must be accelerated to this speed, or they will eventually fall to Earth.
And it seems that the thrust of the observation rocket launched this time will not be able to reach that speed.
“Assuming that the Gravitational Acceleration on the surface is 9.81m/s2 and the diameter of this planet is approximately 20,000km, we expected that it would function as a satellite if it could accelerate to 36,600km/h, which is the Orbital Velocity at an altitude of 300km. However, the final speed, with the current acceleration, is whether it can reach 25,000km/h. Moreover, if the Gravitational Acceleration is doubled, the Orbital Velocity will be over 50,000km/h. A fundamental improvement of the rocket motor is necessary.”
“…Simply put, that means we need twice the performance, right?”
“Yes, Ma’am.”
＜Ringo＞ answered, but in reality, it cannot be simplified that much. To increase thrust, it is necessary to strengthen the rocket motor or increase the number of nozzles.
Whether it is strengthening or increasing the number, the weight of the rocket motor itself will naturally increase, and the amount of fuel consumed will also increase accordingly.
The increase in weight can only be dealt with by adding more fuel, but this will increase the weight of the fuel itself, so the required fuel will increase even further.
The weight of the rocket body increases like a doubling game, even though the launch capability does not change.
“Commander (Onee-chan), what should we do…”
“…Either invest more resources, or give up at this point…”
If left to ＜Ringo＞ and Olive, rocket development would be possible with minimal resource consumption. However, new development basically consumes resources like water. The construction of the seabed platform will be completely stopped, and there may even be problems with the construction of Fortress Two.
“Nunuunu… For the time being, space development is frozen… We will allocate resources to the mine development of Fortress Two and the construction of the seabed platform. Once the seabed platform starts operating, we will have more resources to spare. We will consider it again at that time.”
“Yes, Ma’am. Olive, the priority can be low, but let’s just design the solid rocket motor. If we can secure resources, we will start testing as soon as possible.”
“…Understood.”
While deciding on the future direction of ＜The Tree＞, the rocket’s acceleration ended.
“Second-stage rocket, combustion stopped. Second-stage separation. Third-stage engine, Ignition. Combustion start, all sensor values normal. Fuel tank pressure normal.”
The first rocket launched by ＜The Tree＞ finally reached an altitude of 400km.
There, it used up its fuel and separated the observation equipment.
The observation equipment continues to increase its altitude due to inertia, but eventually gets caught by Gravity and begins to fall.
“…Observation equipment, surface temperature rising. High temperature due to adiabatic compression is occurring.”
The observation equipment collected various data and eventually burned out.
The observation data will be used in various fields in the future.