The arrival of the aliens and subsequently getting to know their history before entering to the Sol system, only worked to confirm what a number of high and middle ranked people in the militaries of the G12 knew already. Space outside of the Sol system was not as secure as many of the optimists liked to think. In turn, this meant that not even the Sol system was really secure from potential attacks from the outside.
In 2020 the first International Solar Defense Conference was held in Geneva, with the goal to further international cooperation and develop strategies to help with the defense of Earth and in extension the Solar System.
Several battle grounds were discussed during the Conference, based on humanities interest in their own solar system. Cislunar space was a given, as Earth needed to be defended at all costs. The Moon was shaping up to become a vital source of raw materials for the emerging cislunar industry and was in need of protection as well.
Multiple layers of defenses were devised, beginning with orbiting satellites like the Soviet Polyus, over armed space stations, to cislunar armed spacecraft, like the US Nike or the EU Traghetto. Ground based defenses on Earth and the Moon were to support the orbital defenses, be it intercontinental nuclear armed missiles, lasers or the lunar mass drivers that were planned.
According to the Quetzal the known method of FTL was limited to areas with a low gravitational gradient of a stars gravity well, known as the Edge by the Quetzal. It varied from system to system and for Sol, the Edge was just outside of Jupiter’s orbit at 5.5 AU distance to Sol.
This added several more potential battlegrounds on the way to Earth.
Mars, being the home of a fledgling colony and several research bases, not to mention the alien ruins of Honore City, was of interest to defend, but for the moment ultimately of a lower value. Some of the defenses used for Earth could be used at Mars as well, be it orbiting satellites or some smaller spacecraft. The most potential had Phobos and Deimos, which could in theory be converted into space stations, with their rocky material acting as armor to protect crew, weapons and even spacecraft hangars.
The battlefield that was interplanetary space was of interest as well, but the sheer size was going to make it a problem to defend at all. At best it was possible to force some running battles in interplanetary space, between interplanetary spacecraft and any invading force. At best the interplanetary space could be observed from cislunar space with IR sensors.
That left the asteroid belt as battle ground. There was great interest in exploiting the material wealth of the asteroid belt and many planners dreamt of colonizing the dwarf planets and asteroids situated there, like Ceres and Vesta. These economic interests would need their own defenses.
The asteroid belt also had the potential to be used as defensive line for threads using the ecliptic to enter the inner solar system. Some asteroids could be expanded into bases for defensive forces and be used against anyone moving through the belt to get to Earth.
By the end of the 2020 ISD Conference the consensus that the cislunar defenses were more important than anything else at the time. This lead to an increase in defensive expenses from the Big Four as well as the other G-12 nations, though those were not only because of the intention to defend Earth, as the rivalries between the Big Four still existed.
Of the alien technologies the weapons technologies proved to be the most valuable for the moment. The basics for these technologies existed already and the alien technologies were in most cases merely more advanced versions.
Lasers and nuclear tipped missiles were the weapons of choice of the Quetzal and the Turukal, while the Quetzal also used kinetic energy weapons, such as spinal railguns, to provide a heavy short range punch against armored targets. All these weapons had shown their effectivity against The Enemy and to the Big Four it was only prudent to use them as base.
Two laser systems were expected to be best for further development.
One was the photonic crystal laser PCL, like the United States had developed from the laser system in the National Ignition Facility. They could be scaled up and down relatively easy and laser amplifiers could be added to boost the beams power. A similar system had been used by the Quetzal and the Turukal.
The other was the free electron laser FEL, that was in development. It was possible to tune the laser to different frequencies, be they in the visible spectrum or the X-ray spectrum. The relative size of the system however made them unwieldy to be used in the turret mounts that were used by armed space craft. Socalled spinal mounts of the weapon, fixed along one axis of a spacecraft was considered to be used for the FEL system, making it a prime candidate for long range use.
Nuclear armed missiles were considered to be the main weapon of any future armed spacecraft. With a relatively high delta-v capacity compared to its low weight nuclear payload, such a missile could be fired at an enemy spacecraft over longer distances than a laser could and keep up with most evasion attempts. Two staged versions were examined to increase the range of the missiles.
For dealing with defensive fire at the nuclear missiles the two staged design could use its second stage to reduce the time if being within the counterfire envelope by doing a terminal sprint. Reducing the cross section of the missile was another way to deal with defensive fire, as was the use of radar absorbing materials to counter radar based point defenses. Decoys used by the missiles, much like they were already integrated into intercontinental missiles, could also decrease the probability of the actual missile being hit.
Conventional kinetic energy weapons, such as the European OTO Melara 76 mm Spazio Super Rapid or the rotary guns used by the others, were only expected to be useful over relatively short distances, as they could only be fired with low relative velocity and allowed the opponent a longer time to dodge.
While lasers were expected to have core ranges of up to 25000 kilometers against large targets for optical lasers, due to beam dispersion and guidance, kinetic energy weapons only had an expected range of about 1500 kilometers, based on the baselines of Quetzal combat ranges.
The Rotary guns were considered to be used as defense against missiles and, together with larger diameter weapons like the OTO Melara, directly against an opposing spacecraft. The larger diameter projectiles had the advantage to carry a small RSC system and a short duration propulsion for terminal guidance as well as explosives.
Very large diameter kinetic energy weapons were even considered to be useful against fixed targets, either space stations or station on the surface of planets, moons and asteroids. The Quetzal already had integrated spinal mass drivers for their combat craft.
While no actual technology was discussed, nor the design of such weapons, 2020 IESD Conference lead to the Big Four developing their own weapons and technologies based on its recommendations.
The followup 2022 ISD Conference was held in Montevideo, Uruguay.
While the Conference saw some refinements of the weapon specification recommendations, the main focus was placed on international cooperation, as a potential extrasolar enemy was unlikely to direct its focus on only one nation and ignore all others.
The conference did not yield much in the way of recommendations concerning joint military maneuvers and tactics. It did however come up with the proposal for an international docking system specially for armed spacecraft, to allow the docking, refueling and restocking regardless of a spacecrafts nationality. This also allowed the use of stations to serve as an alternate fallback point in case the closest stations of a nation were destroyed.
Based on the International Docking Standard the proposal was extended with a number of docking clamps and valves for liquid fuels and oxygen, places in a specific pattern.
Another recommendation was to find a way to use the same propellants for combat spacecraft as a way to reduce logistic problems. The two proposed propellants were hydrogen and water, though water appeared to be more likely to be employed.
The 2022 Conference also saw the formation of the Estévez Group, an international think tank employing several Quetzal and Turukal, as well as Enthat. Named after the Estévez Palace in Montevideo, the Estévez Group was tasked to research and plan the defenses of Earth as well as that of the Solar System and recommend courses of action.
It was hoped that the Estévez Group might provide continuous planning and cooperation between the nations involved in the defense of Earth, compared to the biennial ISD Conferences.
Two international cooperations were another result of the 2022 ISD Conference. NASA and the US Space Force began formal talks with ESA and Euroforce about the development of a common cislunar propulsion system based on a bimodal version of the European Viking nuclear engine, meaning that it could produce electricity like a conventional nuclear reactor, and the US VASIMR engine.
The other was a cooperation between the Asian-Pacific Space Community and the South American Agência Espacial Sul Americana to develop their own nuclear propulsion and advanced weapons to add their own weight into the defense of cislunar space.
In 2024 the ISD Conference, held in Kuala Lumpur, confirmed the first actual steps towards a better defense of Earth and the first area that saw expansion were unmanned orbital defense platforms.
The Soviet Union had designed and built the new Polyus III platform, armed with two infrared 5 MW PCL systems, a single 500 kW FEL systems tuned to far ultraviolet light and eight nuclear missiles. Five of these platforms had been built and launched into semi synchronous polar orbit until August 2024.
The United States had by then designed the Aegis defense platform, armed with three infrared 4.5 MW PCLs, a 155mm spinal KEW emplacement, based on the gauss assisted M723 155mm howitzer used by the US Army. Six nuclear missiles completed the armament. By August 2024 three of these platforms had been launched into sun synchronous polar orbit.
China was in the final construction phase of the Yanhu platform prototype, which appeared to be inspired by the Soviet Polyus III, with two infrared 4 MW PCL systems, one spinal 450 kW near ultraviolet FEL system and eight nuclear missiles. Four more platforms were under construction by August 2024.
Internal politics and similar problems had delayed the European development of the Hoplon platform several times and the production of the initial prototype had only begun by February 2024. The platform was to be armed with four infrared 4.5 MW PCL systems, one spinal mounted 750 kW far ultraviolet FEL system, one. Unlike the platforms of the other Big Four, Europe chose to leave out any nuclear armaments.
Each of these platforms was equipped with a nuclear power system and superconducting capacitor banks for peak combat power.
A joint APSC/AESA proposal for their own orbital platform was an oddball design. The entire system was based on a publicly available NASA contractor report from 1979. Named ‘Initial Conceptual Design Study of Self-Critical Nuclear Pumped Laser Systems’, the study had shown that it was possible to build a nuclear reactor system where supercritical gaseous uranium hexafluoride could be used as power source and lasing medium. While heavy, such a laser would be extremely powerful, while working in the ultraviolet spectrum.
A followup APSC/AESA study had shown that the initial design could be built more compact and used as an orbital platform and was in active consideration by the two lesser space powers.
Cislunar armed spacecraft were still under development at the time of the conference, as were interplanetary spacecraft. Mostly this was due to problems with the armor system the Quetzal had developed and employed. Similar to conventional whipple shielding, the Quetzal armor integrated electrostatic and electromagnetic fields inside the armor to decrease penetration of kinetic penetrators. These fields were presenting a problem for the engineers who tried to further increase the protection, as they tended to disturbed nearby electronics.
The Korean War of 2024 put another problem into the open during the ISD Conference. The destruction of the North Korean weapon satellites by the Chinese had lead to several large debris fields that were hard to counter with Soviet and NASA ‘orbital brooms’. These fields could potentially make low earth orbit operation hazardous and maybe even cause the so called Kessler Syndrome.
As such, dealing with orbital debris became a big topic of the 2024 ISD Conference. The Estévez Group presented a recommendation that was largely based on how the Quetzal had dealt with the same problem. Several private organizations of various Quetzal nations had built manned spacecraft that then had collected the larger pieces of debris and moved them to orbital recycling stations. Smaller pieces of debris had been dealt with by using sacrificial whipple shield armor and aerogel materials to collect them, or spacecraft mounted laser brooms.
With this system the Quetzal had been able to clean up space around their homeworld relatively cost effective.
The ISD Conference of 2026 was held in San Diego.
The Estévez Group had done their own study on the viability of the uranium hexafluoride laser reactor that had been proposed during the previous conference. While the laser reactor could actually be constructed, the usefulness was questioned. Such a laser system had to be of a minimum size to house the gain medium of about 4.6 kg gaseous uranium hexafluoride needed at least needed to have the fission reaction being self sufficient. The construction had to be designed to the limit of the used materials. Weight was another issue as a laser reactor needed heavy shielding to be operative.
The Estévez Group study concluded that the uranium hexafluoride laser reactor was, in the short term a potential weapon to be used in asteroid bases and atmosphereless celestial objects like the Moon. Orbital platforms using such a laser system would be unwieldy and hard to replace on destruction compared to conventional platforms.
Until the beginning of the conference, several prototypes of Cislunar combat spacecraft had been completed, adding a more flexible second layer to the defense of Earth.
NASA and the US Space Force had developed the Optio. The Optio was a 50 meter long spacecraft using a single Unified Propulsion Module that had been developed by NASA and ESA. The single bimodal nuclear thruster and three VASIMR plasma thrusters of the UPM allowed sprinting as well as long duration burns for intercepting other space craft.
It was armed with the same weapons as the Aegis defense platform, though in greater numbers. Five 4.5 MW PCL systems, two 155mm kinetic weapons and eight nuclear missiles gave it a useful offensive punch, while a first generation armor based on Quetzal armor provided a better protection compared to the previous defenses.
ESA and Euroforce had developed a similar armed spacecraft in the form of the Sarissa. Like the Optio, the Sarissa used the Unified Propulsion Module and was about 50 meter in length. Armed with eight 4.5 MW PCL systems, four 750 kW FELs and two OTO Melara 127/64 Spaccio, but lacked nuclear armed missiles. This made the spacecraft largely independent of ammunition and a small fusion reactor with superconducting capacitor banks supplemented the nuclear thruster of the propulsion module in matters of energy production.
To allow long ranged fire, external missile racks had been developed, which could be jettisoned and remote controlled.
The Soviet Union had deployed the Shkval. When compared to the Optio and the Sarissa, the Shkval was smaller with a length of just 40 meter, but with a gaseous nuclear core thruster that was more powerful. The reliance to no less than fourteen nuclear missiles and only three 5 MW PCL and two 500 kW FEL systems to complement them made it a useful long distance combat craft but lackluster on shorter ranges.
China was slightly behind the curve, as they were forced to develop their own nuclear thruster. With a gaseous core nuclear engine they made use of the skills gained from the development of their fission fragment thruster. It had a higher specific impulse compared to the Soviet thruster, but lacked in actual thrust, setting it actually on par with the Soviet system. Their cislunar spacecraft design, the Yue Fei, was considered to be a good design, armed with six 4MW PCL and two 450 FEL systems, combined with ten nuclear missiles.
The 2028 ISD Conference was hosted by the Soviet Union, in Leningrad and revisited several of the points from the 2020 Conference.
The UN Pathfinder Mission, with the Smirnova, Lewis & Clark and Marco Polo surveying the Asteroid belt for potential alien sites, had discovered several asteroids that had been mined out an undetermined time ago. Several experts in the conference noted that these mined out asteroids could potentially be used to house the bases that had been considered for the Belt and provide forces for combat there. Especially two asteroids, 77 Frigga and 46610 Bésixdouze, were of interest as they had several huge cavern like hollow spaces and appeared to have also been used to house mining crews.
The Estévez Group was asked to work on several studies on the subject, to be presented during the 2030 Conference.
During the Conference, four large interplanetary armed spacecraft were under construction in Earth orbit.
It was the first time, NASA and the US Space Force were diverging from the previous design paradigm of using ‘stacks’ of prefabricated parts and dock them together in orbit.
The use of high thrust Z-Pinch fusion thrusters and future magnetically confined fusion thrusters made a new design policy necessary. Taking a hint from ESA and the Chinese, as well as the Turukal, the new Space Force design, the Spearhead Project, was based around a large truss hexagonal structure, large enough to house inflatable habitat modules. Two counter rotating gravity decks provided gravity for the crew, while external docking ports were provided for supplies.
The armament of the design was connected outside of the spacecrafts armor, as were the propellant tanks, able to carry 2500 tonnes of water. Heat management was done by several conventional large radiator panels, while the first liquid droplet radiators design by humans were integrated as well.
The Soviets faced similar problems and decided on a similar solution, which later turned out to be largely due to the existence of a Soviet spy ring in the American industry. As such the new Soviet design shared many capabilities with the US design, though the Soviets used an octagonal truss structure and larger rotating sections.
ESA and Euroforce had made good experience with the Marco Polo and its design and continued to use it. It was however refined with the use of three trusses, for extra load bearing. The spacecraft modules were placed between these trusses and two gravity decks provided habitation space. Over this armor was placed from truss to truss, giving the new design a triangular shape. The armor was only broken in places where the weapons were places and the various docking ports.
China continued to use the Zheng He design, though it was modified for large propellant tanks and fusion thrusters. The dual keel design and its habitation modules were only armored from the outside without changing much of the actual design.
What all these designs had in common was their modularity, including the ability to be equipped with a modular FTL system once such a system could be build by humanity.
By the time of the 2030 ISD Conference in Sydney, the United States had finished their prototype combat spacecraft, the USC Constitution, while the Chinese Nanjing left its berthing for trials during the conference.
Both craft remained within cislunar space, bolstering the defenses for the time being.
The Soviet Ognevoy was completed in March 2031, with the European Argo following in August.
During the 2030 ISD Conference, Enthat suggested to run simulations for an opposing force. As he had the most extensive and practical knowledge on The Enemy, the Big Four agreed on him carrying out a set of simulated battles to test current defense capabilities and proposed tactics.
The outcomes of these tests were definitely not as expected, therefore each of the Big Four as well as the United Nations independently carried out a second run of tests and even a third, using the most advanced and sophisticated supercomputers humanity had, but the result was the same, over and over again.
The first test considered of two simulated enemy spacecraft against the four Earth spacecraft. It ended with the two enemy craft destroyed, but claimed the Constitution and Argo, while leaving the Nanjing and Ognevoy floating in space with heavy damage.
The second simulation was a group of eight enemy spacecraft running against the existing Cislunar defenses. The enemy spacecraft were again destroyed, but in turn had destroyed half of the already considerable cislunar defenses.
In the third and last simulation, a force of twelve enemy craft ran against the combined might of the cislunar defense grid and the interplanetary spacecraft. The result was the mutual destruction of both combatants, with the Nanjing destroying itself and the last remaining enemy craft by ramming.
These tests showed that the defenses of Earth, while able to fight the Enemy, were not adequate at all and had to be increased. At the same moment, tactics and strategies had to be revised to deal with the capabilities of the differing spacecraft designs. The prototype designs for active combat spacecraft were a good first step, but had to be improved in offensive and defensive capabilities.
These problems, set to be revised in the 2032 ISD Conference, were pushed back by another event that happened in October 2031.