Astra Militarum Honours
Known Imperial awards
The Crimson Skull is given to soldiers who managed to successfully give medical aid in a combat situation. It is also common among members of the Officio Cadian Medicae personnel and especially veteran field medics.
Honorifica Imperialis is a term that refers to a number of gallantry medals. Each Segmentum has its own variant, such as the Obscuras Honorifica. The bearer of an Honorifica Imperialis is regarded as a genuine hero of the Imperium and will enjoy the highest regards from his comrades and superiors. 
Order of the Scarlet Wing
A basic medal from the same group as the Order of the Eagle's Claw, the Scarlet Wing signifies that the bearer has been injured but survived a battle in which he has participated in some manner of airborne assault. Injuries in such actions are commonplace, however, and veterans refer to receiving this medal as "getting your wings".
The Macharian Cross is awarded to Astra Militarum officers to reward successful and intelligent application of the Tactica Imperialis in battle. Those who bear it have a chance to be included into the general staff of future campaigns where their skills can be of use.
The Medallion Crimson is a common battle honour amongst veterans of the Astra Militarum. It is given to those who did their duty despite being mortally wounded. As such many are awarded posthumously.
The Medusa Star is a medal that denotes the active military service during the fall of Medusa V. Being the most basic medal common soldiers could receive during the war, it is regarded as having little value.
Order of Ollanius Pius
Ollanius Pius was the lone Man who stood in front of Warmaster Horus during the Horus Heresy, sacrificing his life for the Emperor. His saint-like image is usually on Astra Militarum banners, and this medal is the highest honour a mortal man can earn in the service of the Imperium.
The Ribbon Intrinsic is an award given to units rather than individuals. It is given to squads that have proven to be the linchpin for a victorious battlefront, where they managed to turn a defeat into a victory through sheer determination. The Ribbon Intrinsic is said to forge a great bond between members of a platoon, though in practice, the Ribbon is usually awarded only to a handful of individuals, who are the survivors of gruesome battles they would rather forget. The medal itself is of low material value and takes the form of an etched brass strip with a tripartite ribbon hanging beneath.
Star of Terra
The Star of Terra is the highest military honour a soldier can achieve in his lifetime. Notable bearers of this award include Sergeant Lukas Bastonne of the Cadian Shock Troopers and Guardsman Sly Marbo of the Catachan Jungle Fighters.
The Triple Skull medal is bestowed upon those who were in a unit that suffered at least 66% casualties and survived. It is seen as inferior to the Golden Skull, which is given posthumously to the fallen of such actions.
The Winged Skull is earned by those who have demonstrated inspirational leadership which led to victory. It is often displayed on the shoulder guards of armour. The medal itself of ancient origin and its design of a skull with an iron device has been adopted by the Space Marines as an insignia for a Sergeant.
Known Cadian awards
A medal given to Cadian soldiers and personnel from associated military organisations (including the Imperial Navy and the Officio Medicae) for acts of valour beyond what is required. However, this does not apply to acts that are considered "extraordinary", which leads many bearers to joke that they are the "boring heroes" within their regiment. These who do not own this medal still regard it as a symbol of courage.
Knight of Medusa
Merit of High Lords
The Merit of the High Lords is a rare honour given to Cadian commanders. Those who receive it had their names mentioned in the Chamber of the High Lords of Terra. It is nicknamed the "double-edged sword," as it inevitably means the individual who receives it will be under particular scrutiny from his superiors. He can expect to be assigned by jealous superiors to the most horrific battlefronts, ostensibly in order to pass on his wisdom and courage first hand.
Merit of Terra
The Merit of Terra is awarded to Cadian soldiers who have voluntarily postponed their own demobilization, thus serving much longer than expected. It is seen as a sign of loyalty and self-sacrifice, which all Imperial military personnel respect, reportedly even Space Marines.
Order of the Eagle's Claw
Awarded to Cadians who have made landfall in the most perilous landing zones and triumphed. Requires proven victories against overwhelming odds witnessed by their superiors or Imperial Navy overseers. Brings increased respect from the Navy.
Order of the Storm
The Order of the Storm is a campaign medal given to soldiers who have been wounded during the Medusa V campaign and managed to return to their units. Variants include the so-called "double storm" and "triple storm", earned by those who have been wounded several times.
Dubbed the 'lunatics eagle', the Steel Aquila is awarded only to Guardsmen of the Cadian 91st who were successful in the face of danger and managed to return fit for duty. It is usually only given in the most violent or impressive of cases. 
The Valoris Imperator is awarded to veterans who have served in the Cadian 91st for 20 years or more. While technically a recognition of long and steadfast service, it is usually only awarded posthumously to long standing veterans who have died in particularly unpleasant circumstances.
Ward of Cadia
This is debatably the highest honour a Cadian can be presented with, given for extraordinary courage and determination in the face of extreme danger. Once given, the bearer is referred to as Warden or "Bearer of the Ward". A notable bearer is Warden-Colonel Parmenion Thade, given to him after he led a company of his men into the tunnels of Cadia, killing several Chaos Space Marines and in the destruction of a Chaos Titan at its inception during the 13th Black Crusade.
- 1: Codex: Imperial Guard (3rd Edition, 2nd Codex), pgs. 14, 35
- 2: Codex: Imperial Guard (5th Edition), pg. 59
- 3: Codex: Catachans (3rd Edition), pg. 23
- 4: Imperial Munitorum Manual (Background Book), pgs. 80-84
- 5: Rogue Star (Novel), [Needs Citation]
- 6: Cadian Blood (Novel), [Needs Citation]
- 7: Warhammer 40,000: Dawn of War II - Retribution: The Last Stand - Duelist Honors, wargear selection screen