Abnormal Chemical Material or more commonly referred as A.C.M. was a material that was considered as junk in early era of space age. No usage for the material was found and was discarded during mining.

ACM was a silvery material that is very much like lead. It shared similar texture and had similar material hardness. It wasn’t harmful to human body however unless it’s introduced directly into system. Furthermore, unlike lead, its melting temperature was 5,800 Celsius.
Due its high resistance to heat, ACM was considered to be used as a heat shield. However, its softness resulted in the material being peeled off from atmospheric entries. There were further difficulties in attempting to produce ACM alloys in early space age.

A.C.M. was considered more valuable than gold or now-extinct Petroleum.

Discovery

ACM was originally discovered on Mars and was predominantly found on Mars in Sol system. ACM wasn’t found elsewhere else in abundant quantities until Andromeda cluster was explored.

ACM was also found scantily on random asteroid belts, namely Kepler belt, outside of Sol system. All of this meant that United Sol relied heavily on Mars to provide them with ACM.
After Mars became independent, the Dietrich clan had full control over the price of ACM within Sol system which had a direct effect on economy of United Sol and contributed in downfall of United Sol. Meanwhile, the Dietrich clan provided Venus with relatively inexpensive ACM.

Its first usage

In early 8900, Dr. Cezary invented a revolutionary shielding technology by using ACM. He discovered that ACM had an ability to push away physical and energy (as well as thermal) forces when it was charged with electricity.

Before this point, space ships in Two Clusters had no shielding and relied on thick armors. Thick (dual armor layers) armor was the signature of USF Courage as a result.

Furthermore, he also discovered that, when negatively charged, ACM would try to absorb energy from matters by breaking it down.
ACM reactor was invented by using negatively charged ACM core within an egg-shaped container. Converters was placed around the negatively charged core and it delivered electricity when placed matters inside of it. The reactor would break matters (any matters) down to atom level and absorbed energy from it. Its byproduct was ion particles which were used for ion engine and thrusters on spaceships.

Fuel for ACM reactor

ACM reactor generally came in an egg-shaped container that was a size of a small 2-story building. Such a size would be enough to power a cruiser. Fuel for ACM reactor varied, but for space ships, human and food wastes were used as fuel. For cities, garbage was used as fuel.

Many considered ACM reactor green since all it did was breaking down matters. However, it must be noted that, if left unattended, ACM was capable of breaking down a whole planet. It was unlikely to happen since the converters would overload and negatively charged core would be positively charged, making it stable. But Dr. Cezary insisted that negatively charged ACM core was extremely dangerous to be used to power cities.

Regardless, most cities chose to use ACM reactors because majority of experts disagreed and actually recommended ACM reactor over other forms of energy sources.

Shields (plural)

Dr. Cezary developed ACM alloys and arrays specifically developed to maintain and control ACM push force. Due to ACM’s low hardness, it wasn’t ideal to be used as surface of a ship. Therefore, ACM was deployed in an alloy form with either steel or aluminum.

On a cruiser, there were generally six arrays responsible of controlling and maintaining a shield cover.
Front, back, top, down, left and right, six arrays existed on a ship and each array was independent. It was also possible to regulate powers between arrays.
This system also allowed point-to-point defense system where a spaceship would create a partial shield when a friendly unit was too close.

Shield resistance

ACM shield was effective against kinetic and thermal types of energy. ACM’s “push force” showed no protection against explosive and ECM damages. However, kinetic and thermal type covered pretty much all types of damages until the alien invasion. (Much later in the story)

Finally, below is a render of a USF Courage engine room where it displays the egg shaped A.C.M. reactor.