The Transsagittarian Hyperlane Network refers to a series of hyperlanes in the Via Sagittaria Galaxy controlled by the United Federation of Star Systems which acts as the primary backbone of transgalactic travel within the Via Sagittaria.
During the era of the Yohjan Confederacy, as human presence became more widespread throughout the galaxy, singular hyperlanes became less and less sufficient to maintain the needed trade and especially military transit between the main regions surrounding Helyar and the peripheral regions, especially those on the other side of the core. While the concept of a transgalactic route has been floated as early as 5,000, it wasn't until 12,800 when such proposals were seriously considered and a number of feasibility studies conducted.
Around this time, new developments in space-clearing technology significantly reduced the cost of hyperlane construction and enabled longer single hyperlane jumps, from just over 100 light-years to nearly 1,000. This significantly changed the calculations for the construction of such a transgalactic lane, as this meant that it could be constructed for an order of magnitude less in cost. Soon enough, a route which circumnavigated the difficult core region was accepted as the going plan, and several existing hyperlanes were integrated into the plan.
The course of the network is not a single uninterrupted jump - in fact, it is typically designed so that a single jump would take approximately four hours - roughly 600-700 light-years in the rimside or 100-150 light-years nearer the core, and this allows both for travellers not seeking to go the entire way of the route to exit at a convenient position or for the route to be constructed flexibly not in a straight line.
There are two main types of routes within the network, rim-core and the loop. The loop route circles the Core Systems just slightly outside of the bump in density, while the rim-core routes link the loop to the four termini systems. There are no specific connection points between the rim-core routes and the loop, and the rim-core route splinters and widens into multiple systems upon contact with the main loop.
The four termini systems, all located in the galactic rim, are:
All four of which are major human population centers with habitable planets (or, in the case of Helyar, with Aegyn as a planet) prior to the completion of the network, and afterwards became even more populated.
Most points in the network are connected to a large number of spur lanes, which have considerably lower capacity and is often not run by the UFSS itself, but by private operators or regional governments. Regardless, these spur lanes are typically still considered major routes and is essential for connecting many systems to the network.
The network is not significantly used for large-scale commerce or transport, as this is primarily dependent on more local hyperlane networks. However, in transporting more high-value goods produced more scarcely the network has proven essential. Its primary purpose, however, is not cargo transport, but military and passenger transport. Using the network, the UFSS could transport military personnel and ships to any point in the galaxy within a short period of time without any risk of interception and without being dependent on controlling the other end of the trip. The network also resulted in a significant boon to long-distance tourism, and while relatively small there is still a industrial cargo network which takes advantage of the hyperlane network.
It is primarily still important for military affairs, however. During the Split of the Lactean Confederacy, many historians today believe that one key reason for the relatively fast reunification of the Via Sagittaria was the UFSS' control over the hyperlane network, which provides it with significant military advantage and economic leverage during negotiations for annexation, or outright conflicts.
The network is run by a dedicated department within the UFSS, and it typically permits vessels to transit the route for free. However, it does charge usage fees for large-scale commercial users such as megacorporations or other governments.