Starpod

A "wall" beyond the skies of Terra stops its denizens from reaching out into the space... and, unbeknownst to them, keeps Terra safe from both threats from beyond and danger from within.

The fake sky, or poetically called the "Starpod", is a "wall" (more appropriately "barrier") that surrounds the world of Arknights. It is the main subject of Lone Trail after being previously alluded to at the end of Dorothy's Vision.

Overview

Existing at the altitude between 6,152.31 m to 6,972 m above sea level, placing it around Terra's troposphere, the Starpod is likely made up of concentrated high-energy particles that tears apart any object attempting to pass through it by destabilizing their integrity and causing Arts devices to fail, thus having a major ramification of preventing the Terrans from achieving orbital flight or spaceflight. The Starpod also causes gravitational lensing that deflects starlight, making it difficult for the Terrans to accurately observe celestial bodies due to their orbits being displaced. It is impossible for the current Terran technology to penetrate the Starpod as doing so would require an astronomical amount of energy – equal to that provided by the entire Terra and outside of Originium's limits. Even if the Starpod is ever broken, its particular nature means that the damage is temporary and the Starpod will regenerate itself within as long a few years to as short as within days.

The Starpod theory is attributed to Leithanian professor Sinach Weber of the Gutenberg Universität, which was originally formulated as a way to explain his hypothesis regarding the existence of an endless sea of Originium sprawling beyond the stars, taking on consideration how it supposedly came to Terra through cosmic impacts (i.e. meteorites). However, this theory was left forgotten in the world of science, and hasn't been proven through scientific means. On the other hand, the Terrans know neither the Starpod's origin nor its function, with the most prevailing theory being "Originium insulator hypothesis" in which it is formed by Catastrophe clouds lying at 6,000m above sea level and to protect the Terrans from Originium above. While this is backed by several evidences, Originium particles can be found past the Starpod, hence Originium is not the cause. Another theory is the "organic isolator theory" proposed by Kazimierzian scientists where the Starpod itself is organic and alive, although it was confirmed that the Starpod is inorganic. Nevertheless, many of these theories are considered outdated and full of inconsistencies.

However, the Starpod's true origin and function could be far beyond the current Terrans' understanding. It is possible that the Starpod was created by the "First Civilization" in the aftermath of a certain "disaster from above" that results in their annihilation; as Kal'tsit expresses concern at Kristen Wright's attempt to break through the Starpod, it can be surmised that it is either created to protect Terra from the alien Observers that wiped out the Civilization or contain Originium in the planet, preventing it from ever being unleashed into the universe. In fact, in a possible alternative timeline, Originium managed to break through the Starpod and assimilates other planets and lifeforms beyond Terra.

A hyperbeam is launched right into the Starpod...

...creating a gap which exposes one of Terra's Twin Moons for every Terran to see

Attempts were made to explore beyond of the Starpod, but were doomed to fail. Notably, Kristen Wright's parents tried to fly high above the Starpod via a high-altitude aircraft which predictably results in their demise, although their sacrifice allowed the Terrans to pinpoint the Starpod's boundary. The last try was a Leithanian Arts Detector Orb that crashes after flying around 500m above sea level, and since then, the Terrans completely abandoned their interest to explore the Starpod.

However, after discovering the Hall of Stasis, a complex of First Civilization Sarcophagi below Trimounts tended to by Friston the Preserver who shared his knowledge regarding the Starpod to Kristen, she managed to found a way to break through it: by using the Hall's Sarcophagi to power up the S.H.A.F.T. and relaying it into the H.A.M.H.R.R. on the Galleria Stellaria sub-orbital platform developed as part of Rhine Lab's Project Horizon Arc to fire off a hyperbeam at the Starpod, the energy generated through these endeavors theoretically should be enough to pierce the Starpod.

Upon the execution of the plan despite some interference, as Kristen correctly predicts, the hyperbeam fired by the H.A.M.H.R.R. momentarily creates a disruption on the Starpod, resulting in aurora-like phenomenon visible across Terra, before dispersing its particles and creating a large gap, or "hole" in the sky, from which one of Terra's Twin Moons is clearly visible for the first time ever in Terra's recorded history and Kristen had the Galleria Stellaria travel to outer space as well. The gap in the Starpod created by Kristen allows the Terrans to study more about the space beyond the planet, ushering a new era in the Terran astronomy. By the end of the The Rides to Lake Silberneherze event, an agreement has been reached by both Rhine Lab and Karlan Trade to build a Starpod Research Station near the peak of Mount Karlan in Kjerag for research and Starpod launch test purpose.

As the Terrans had to use "The Door" to reach out into other planets five centuries in the future, it can be assumed that the gap in the Starpod created by Kristen has been closed at this point.