Castor 3151.svg
System Information
X:Y Coordinates-40.43 : -16.683[e]

The Castor system is home to at least one habitable world and as of 3151 was located in the Wolf Empire.[1]

System Description[edit]

Castor is located near the Devil's Rock and Pollux systems.[2][3] Relatively little information is available on the Castor system, but it is known that the system has at least six planets, and that at least one of those planets is inhabited and is an eight-day transit from the system nadir jump point at an acceleration of 1g. It is also known that the sixth planet in the system, Castor VI, has several moons, and that just beyond the orbit of the most distant of those moons is a known pirate point.[4]

System History[edit]

The Castor system was colonized at some point during the First Exodus from Terra[5] and was a member of the Terran Hegemony by the time the Capellan Confederation was founded in the mid-twenty-fourth century.[6]

Amaris Civil War[edit]

The Castor system became the resting place of the SLS Nelson, a Black Lion-class battlecruiser and winner of the Star League Defense Force Martial Olympiad in 2732; the Nelson played an important part in the liberation of Oliver, but took heavy damage in the process. The crew of the Nelson managed to nurse her as far as the SLDF fleet station in the Castor system, only for the SLDF command to declare that the Nelson wasn't considered a viable candidate for repair. As a result of this decision the Nelson was scuttled and abandoned in a long elliptical orbit around Castor.[7]

Clan Invasion Era[edit]

With the assistance of the Word of Blake, the Free Worlds League discovered the location of the SLS Nelson in the Castor system and retrieved her, transporting her to the Ionus system to be repaired in secret at the Illium Naval Yard before returning her to active service under a new designation, that of the FWLS Xanthos.[7]

Political Affiliation[edit]

Castor VI[edit]

Castor VI
System positionSixth[citation needed]
LandmassesAt least 1 (Acaba)[42]

Planetary History[edit]

Reunification War[edit]

By the end of the Reunification War, Castor was a world within the Tyrfing Province of the Terran Hegemony.[10]

Star League Era[edit]

When Stefan Amaris launched his fateful coup, the Thirty-eighth Amaris Fusiliers were at the forefront of efforts to secure Castor for the Amaris Empire. Over the next decade the Fusiliers worked to maintain control of Castor, using various strong-arm tactics to raise a strong Patriot contingent on the planet, whilst imprisoning government officials and other prominent citizens. Hundreds of thousands were imprisoned and their valuables confiscated, and tens of thousands of those imprisoned were never seen again during the Fusiliers' tenure on Castor.[43]

In January 2775, Stefan Amaris redeployed large numbers of Amaris Empire Armed Forces to a dozen worlds, including Castor. AEAF units had used weapons of mass destruction regularly against SLDF units throughout the Hegemony Campaign, predominantly to either damage the SLDF units targeted or to strike at civilian targets to prevent the SLDF from obtaining resources and supplies. In this case, Amaris' orders were different: he intended to create scorched wastelands that Commanding General Aleksandr Kerensky would have no choice but to try and clear, whilst saddling the SLDF with huge numbers of sick and starving civilians. The AEAF units deployed to Castor and the other eleven worlds due to be abandoned by Amaris launched large-scale WMD attacks with one purpose: to ravage the worlds, preventing them from sustaining either their human populations or their various industries... to create wastelands.[15]

The AEAF tactics on Castor were both brutal and brutally effective. Kerensky deployed twelve corps of SLDF personnel into Amaris Empire space, and each discovered the same horrific situations. Forced to deploy the SLDF reserve into action, by February Kerensky had almost a hundred SLDF divisions either on the twelve ravaged worlds or en route to them, trying to provide aid to the populations and to clear up what damage they could.[15] Castor fell within the operating area of Task Force Commonwealth, and the Second Army Group deployed to try and assist the population.[44] The devastation wreaked across Castor and the other worlds bought Amaris time; for several months Kerensky was unable to resume offensive operations because of a lack of resources, and ultimately the Commanding General had no choice but to call on the Capellan Confederation, Lyran Commonwealth and Federated Suns to provide relief where they could.[15]

Having scorched Castor, the Thirty-eighth Fusiliers ignored the order to withdraw to Terra, instead abandoning Amaris and heading into the Free Worlds League, where they promptly vanished—one of five assorted Republican regiments identified by historians as having escaped from the occupation of the Hegemony largely intact.[43]

Second Succession War[edit]

In 2838, the Free Worlds League Military was struggling under the combination of the ComStar interdiction of the Free Worlds League and Parliament's efforts to choke off funding to the military. Both the Capellan Confederation and Lyran Commonwealth had taken advantage of the League's woes to make military gains, with the LCAF expanding two major salients into the League with ruthless efficiency. However, in 2838 the FWLM forces fighting a tenacious defense in the League systems of the former Terran Hegemony found their LCAF opponents being hampered by expeditions from the Draconis Combine and Federated Suns, both looking to make gains of their own from the weakened League. Castor was one of the systems caught up in this - the LCAF had landed the Seventeenth Skye Rangers on the planet to destroy the defending FWLM garrison and occupy the world, only to have the Third Ceti Hussars land on the world later to try and claim it for the Federated Suns. Although the LCAF managed to rebuff the Ceti Hussars and finally claim Castor in spring 2839, by the time they had secured the world the interdiction had ended.[23]

Third Succession War[edit]

In June 3011, two mercenary units in the employ of the LCAF, Snord's Irregulars and the Kell Hounds launched a joint attack on Castor. The mission was to find and destroy a rumored stockpile of old nuclear weapons, and to give the Kell Hounds some combat experience in the process (their first combat mission in fact);[45] Cranston Snord also intended to try and acquire a collection of Fabergé eggs believed to be on Castor, and to have the Irregulars humiliate the Thirtieth Marik Militia. According to subsequent commentary from Captain Jonathan Taylor, Thirteenth Marik Militia, Second battalion, First company, Cranston Snord personally destroyed his Centurion during that joint raid, indicating that at least elements of the Thirteenth Marik Militia were involved in the fighting.[46] The attackers managed to identify and destroy the weapons cache just before the defenders could use the nuclear weapons on the attackers with the intent of framing them for using them. By lucky chance, Cranston Snord, while looking for the Fabergé eggs, apprehended Colonel Nage of the Thirteenth Marik Militia in the open market of Alfagemini City and also ultimately managed to secure nine Fabergé eggs for the Irregulars' museum on Clinton.[25]

Fourth Succession War[edit]

Following the sudden invasions of several League worlds by the Tikonov Free Republic and a daringly successful invasion of Callison by mercenaries employed by the Lyran Commonwealth in mid-3029, Captain-General Janos Marik found himself in the midst of an unanticipated crisis. In addition to the conquest of Callison, LCAF communications traffic and movements had spiked sharply, creating the impression of an impending offensive against the League. Faced with what he believed to be the plausible threat of a large-scale attack aimed at the region of the League near Terra, Janos was more concerned with saving the six or seven assorted BattleMech regiments present within the region than he was with retaining the worlds, as he believed that the offensive would most likely be aimed at snipping off the corner of the League closest to Terra - and to both the Federated Suns and the Tikonov Free Republic. Castor was one of the systems abandoned by Janos, who would learn later that he had been deceived by an effective campaign of smoke and mirrors arranged by the Commonwealth General of the Armies, Edward Regis, to deter the League from launching an invasion of the Commonwealth while the LCAF was heavily committed to its invasion of the Draconis Combine.[47][48][49]

Operation GUERRERO[edit]

Castor was invaded in the second wave of Operation GUERRERO by the Third Sirian Lancers. The few planetary militia units on planet were easily defeated.[50][51]

The Jihad[edit]

On 23 September 3075, Castor was one of three worlds in the Protectorate to be raided simultaneously by unidentified forces. The raiders damaged the defending Protectorate and Militia forces, and were rumored to actually be drawn from the Word of Blake's own Shadow Divisions.[52][53]

Military Deployment[edit]


The planet has at least one continent named Acaba.[42]

Planetary Locations[edit]

  • Alfagemini City: a city[25]
  • Geoffrey Nature Preserve: nature preserve and site of a battle during Operation GUERRERO.[51]
  • Jaffe Farm: site of a battle in 3149[42]


It should be noted that different years have been given for the 3011/3012 raid on Castor conducted by Snord's Irregulars and the Kell Hounds. The history section of the Kell Hounds sourcebook is ambiguous, noting on p. 5 that the raid was planned in 3011 and then narrating how Snord's Irregulars and the Kell Hounds approached Castor from two directions around 7 June, without stating a year. On page 7, however, it is narrated that the Kell Hounds only returned from the mission in the fall of 3012. In the sourcebook's scenario section, the two scenarios referring to the Clinton battle on pp. 30–31 ("Lowering the Boom") and 56 ("Delta Romeo") are both dated 15 June 3012. Similarly, Capt. Taylor states he fought the Kell Hounds and Snord's Irregulars on Clinton in 3012.[46] When Lowering the Boom was republished via BattleCorps in 2008 the timestamp was changed to 7 June 3011; whilst this seems to be an oversight based on p. 5 of the Kell Hounds sourcebook, the reprinted BattleCorps scenario is the more recent publication, and the dates in that source have been given primacy in this article.

Map Gallery[edit]

Nearby Systems[edit]

Closest 80 systems (79 within 60 light-years)
Distance in light years, closest systems first:
Devil's Rock 4.5 Pollux 9.0 Zosma 11.6 Oliver 12.9
Tabit 13.7 Denebola 15.3 New Dallas 17.0 Afleir 17.5
Graham 18.0 Zavijava 18.5 Marcus 18.5 Talitha 19.1
Xi Ursae Majoris 20.1 Callison 22.2 Lipton 24.0 Hechnar 25.4
Chara 25.7 Van Diemen 26.1 Connaught 27.4 Wyatt 28.1
Bordon 28.1 Thorin 29.9 Dubhe 30.2 Haddings 30.8
Milton 30.9 Alchiba 33.0 Tau Ceti 34.3 Chertan 34.3
Muphrid 34.4 Carver 35.2 Wing 35.3 Alioth 35.8
Procyon 35.8 Dieudonné 36.0 Acubens 36.0 Phecda 37.2
Zollikofen 37.8 Hall 38.2 Cor Caroli 38.9 Sirius 38.9
Menkent 39.7 Remulac 39.8 Mizar 39.9 Irian 40.2
Outreach 41.4 Alhena 42.1 Nathan 42.1 Rigil Kentarus 42.2
Summer 42.9 Wasat 43.1 Alphard 43.3 Sol 43.7
Keid 44.0 Miaplacidus 45.9 Killbourn 46.2 Rocky 47.7
New Home 47.8 Brownsville 48.7 Shiloh 49.1 Savannah 49.3
Aquileia 49.3 Pliska 49.5 Yorii 49.8 Mandal 50.5
Blue Sava 50.6 Galatea 52.5 Gacrux 53.6 Bryant 53.7
Catroxx 54.1 Chisholm 54.2 Capolla 54.4 Caph 55.7
Alcor 57.0 Altair 57.9 Lyons 58.1 Syrma 58.5
Epsilon Eridani 59.0 Elbing 59.5 Hsien 59.5 Augustine 60.2


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  2. 2.0 2.1 Era Report: 3145, p. 39: "Inner Sphere - 3145"
  3. 3.0 3.1 Field Manual: 3145, p. VI: "Inner Sphere - 3145"
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  6. 6.0 6.1 Handbook: House Liao, p. 17: "Capellan Confederation Foundation [2366]]"
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  12. Historical: Liberation of Terra Volume 1, p. 11: "Inner Sphere - 2765"
  13. Historical: Liberation of Terra Volume 1, p. 104: "Rim Worlds Republic - [2767] Map"
  14. 14.0 14.1 Historical: Liberation of Terra Volume 1, p. 138: "Operation LIBERATION Wave 1 [July 2772 - December 2774]"
  15. 15.0 15.1 15.2 15.3 Historical: Liberation of Terra Volume 2, p. 33: "Planets on Fire"
  16. 16.0 16.1 Historical: Liberation of Terra Volume 2, p. 118: "Digesting the Hegemony"
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  21. First Succession War, pp. 112–113: "Inner Sphere - [2822] Map"
  22. Second Succession War, pp. 18–19: "Inner Sphere - 2830"
  23. 23.0 23.1 23.2 Second Succession War, p. 44: "The Four-Front War: Operation COOKIE JAR and the ComStar War (2837-2842)"
  24. Handbook: House Marik, p. 38: "Free Worlds League after Second Succession War [2864] Map"
  25. 25.0 25.1 25.2 The Kell Hounds, pp. 5–6, 31
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  27. Handbook: House Marik, p. 51: "Free Worlds League after Fourth Succession War [3030] Map"
  28. Historical: War of 3039, p. 133: "Inner Sphere - 3040"
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  30. Era Report: 3052, p. 24: "Inner Sphere [3052] Map"
  31. Era Report: 3062, p. 10: "Inner Sphere [3057] Map"
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  33. Era Report: 3062, p. 28: "Inner Sphere [3063] Map"
  34. Jihad: Final Reckoning, p. 43: "Inner Sphere Map - [October 3067]"
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  36. Field Report: FWLM, p. 17: "FWLM Deployment Map [3079]"
  37. Jihad: Final Reckoning, p. 62: "Inner Sphere Map - [March 3081]"
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