Books like 'Sigma Protocol'
Readers who enjoyed Sigma Protocol by Michael Penmore also liked the following books featuring the same tropes, story themes, relationship dynamics and character types.
sc-fi military, war & conflict space amnesia military colonization space-travel space-opera soldiers exploration
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Retaliation by Ryk Brown
Rated: 4.50 of 5 stars · 12 ratingsPart 2: Episode 10 A ship unable to defend itself… A captain determined to revive her… Worlds dependent on them both to survive… An enemy bent on their destruction… With the Aurora unable to fight, the Karuzari Alliance must find a way to not only repair their flagship, but to make the enemy pay dearly. Sometimes, you just have to make do with what you've got... -
![No Retreat by J.N. Chaney, Terry Mixon]()
No Retreat by J.N. Chaney, Terry Mixon
Rated: 4.50 of 5 stars · 12 ratingsWhen things are going to plan, check to see what you’re missing.Admiral Jack Romanoff and his crew are trapped inside the Confederation proper and facing an unknown number of alien attack ships. They’d thought the Tardan military was defeated, but they’d been wrong. Now they were trapped in a fight they couldn’t lose.When everything seems exactly as you’d hoped, figure out what you’ve missed... -
![Under Siege by J.N. Chaney, Terry Mixon]()
Under Siege by J.N. Chaney, Terry Mixon
Rated: 4.50 of 5 stars · 12 ratingsOnly one world in the cluster remains in enemy hands.Admiral Jack Romanoff and his crew have one remaining nut to crack before they can turn their attention to the people that overthrew the Confederation. The Vesuvius system has become a fortress, so it won’t be an easy fight, but it is one they cannot lose and survive.When force alone won’t do the trick, add guile... -
![Operation Liberty by J.N. Chaney, Terry Mixon]()
Operation Liberty by J.N. Chaney, Terry Mixon
Rated: 4.50 of 5 stars · 12 ratingsAliens invaders hold human worlds. That cannot stand.Admiral Jack Romanoff and his crew have defeated the Locusts once and for all, but they are far from the only invaders infesting the Confederation. The time to go after the xenophobic Novarites and free those worlds has come, and nothing will stand in his way.If words aren’t enough, show them your teeth and bite deep... -
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![A Price Too High by Ryk Brown]()
A Price Too High by Ryk Brown
Rated: 4.59 of 5 stars · 20 ratingsPart 2: Episode 12 …An enemy in retreat …A new world to protect …A new potential ally on the horizon …A new chance to go on the offensive The Dusahn have taken a massive blow, and with the Aurora’s improved jump range, Captain Scott and the Karuzari Alliance can finally keep them at arms length... -
![Commander by Richard F. Weyand]()
Commander by Richard F. Weyand
Rated: 4.71 of 5 stars · 7 ratingsTHE EMPIRE’S NEW NAVYThe Emperor Trajan is building a powerful new navy for the Sintaran Empire. Remotely piloted warships can accelerate faster than humans can withstand, and ships spend so much time in hyperspace, a single crew can man multiple ships, solving the perennial manpower problem... -
![Empire by Joshua Dalzelle]()
Empire by Joshua Dalzelle
Rated: 4.63 of 5 stars · 8 ratingsThe final fight for control of humanity begins now.The United Terran Federation is on the brink of collapse after a devastating attack by the Eastern Star Alliance that has left four planets depopulated and uninhabitable. Terrified member worlds are fleeing from the Federation and the remnant of their once-mighty fleet has retreated to the last place they are welcome: Earth... -
![Destroyer: A Military Space Opera by Craig Martelle, Michael Anderle]()
Destroyer: A Military Space Opera by Craig Martelle, Michael Anderle
Rated: 4.63 of 5 stars · 8 ratingsHumanity’s greatest export—Justice. Peace can never last.When things are going right, be very afraid. The laws of chance are coming.And they’re bringing an alien destroyer, invisible to systems, sensors, as well as the naked eye. Even Ted is stymied. Kill or be killed.Terry Henry Walton isn’t afraid to do things the hard way, and he shows everyone what that means...Categorized as:
space-opera exploration military space-travel soldiers sci-fi fiction genetic-engineering -
![The Colossus by Jay Allan]()
The Colossus by Jay Allan
Rated: 4.50 of 5 stars · 10 ratingsThe Hegemony strikes again… The Confederation and its allies have won their first victory, retaken their capital from he forces of the Hegemony. But the enemy is not beaten, far from it, and they are back, with an unstoppable weapon, a vast superbattleship, a deadly hybrid of imperial and Hegemony technology, called the Colossus...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Fires of Oblivion by Anthony James]()
Fires of Oblivion by Anthony James
Rated: 4.50 of 5 stars · 10 ratingsCaptain John Duggan rots in his cell, facing execution at the hands of his captors. Having discovered the secret which the Ghasts wished to remain hidden, he is left powerless to find answers to the questions which will determine the future of the Confederation. Elsewhere in the Garon sector, the Dreamers have been putting their own terrible plans into action... -
![The Price of Liberty by D.J. Holmes]()
The Price of Liberty by D.J. Holmes
Rated: 4.50 of 5 stars · 10 ratingsWar has been declared. The Indian Star Republic has landed ground troops on the newly discovered colony of Haven as they seek to seize access to the alien worlds of Vestar and Kulthar. The British Star Kingdom has reacted. A battle fleet has been formed with orders to drive off the Indians and retake Haven...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![The Lost Supernova by Vaughn Heppner]()
The Lost Supernova by Vaughn Heppner
Rated: 4.42 of 5 stars · 12 ratingsAndroids used to mingle among us, pretending to be human. Then an alien puppet-master altered their programming. Unknown to us, androids began leaving human society, burning their clothes and peeling off their skin to reveal the chrome-colored bodies underneath. They gathered in a system were a star had exploded, blowing away the atmosphere of a Jupiter-like planet...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Earth Ascendant by Raymond L. Weil]()
Earth Ascendant by Raymond L. Weil
Rated: 4.42 of 5 stars · 12 ratingsFrom USA Today Bestselling Author Raymond L. Weil comes the second book in a new military science fiction series.The war between the seven alien races of the Confederation and Earth heats up as the two come into direct conflict over the former Human Empire. The people or Earth are determined to free it, and the Confederation is determined to keep it under their strict control... -
![The Lost Swarm by Vaughn Heppner]()
The Lost Swarm by Vaughn Heppner
Rated: 4.42 of 5 stars · 12 ratingsStar Watch stands guard over the Commonwealth, having defeated New Men, massed Swarm fleets and android attackers. The victories have cost lost ships, slain crews and smashed star systems. The accumulated damage means that Star Watch now strains to keep order as political instability, increased space piracy and rebellions stretch the stellar organization to the limit...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
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![The Lost Artifact by Vaughn Heppner]()
The Lost Artifact by Vaughn Heppner
Rated: 4.36 of 5 stars · 14 ratingsStar Watch defeated the Swarm Invasion Fleet, but at a terrible cost in destroyed star systems, smashed battleships and billions of dead. In the aftermath of the costly victory, chaos threatens as worlds leave the Commonwealth of Planets, face mass starvation or succumb to increased piracy. The war against the Swarm Imperium has just begun. Humanity needs unity or each planet will fall alone...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Empire's Gambit by D.J. Holmes]()
Empire's Gambit by D.J. Holmes
Rated: 4.67 of 5 stars · 6 ratingsThe Karacknid assault on Earth has been turned back at great cost to both sides. Only the intervention of the Kulreans saved Humanity’s homeworld from certain destruction. Yet the Kulrean worldships cannot be used for offensive operations. This means Humanity and her allies have only a few months of respite before the Karacknids can make good their losses... -
![Nemesis of Mars by Glynn Stewart]()
Nemesis of Mars by Glynn Stewart
Rated: 4.67 of 5 stars · 6 ratingsA failed attempt on the Mage-QueenAn old friend from the gutterAn enemy that should be dead...When a kidnapping attempt on the Mage-Queen of Mars is thwarted by luck, leaving thousands dead in its wake, Prince-Chancellor Damien Montgomery returns to field operations one more time. The evidence leads to one place: Tau Ceti... -
![Leviathan's Fear: A Military Sci-Fi Series by Craig Martelle]()
Leviathan's Fear: A Military Sci-Fi Series by Craig Martelle
Rated: 4.67 of 5 stars · 6 ratingsTrapped in Ga’ee space, Leviathan runs for its life.And the lives of its crew.Declan Payne and Harry Wesson decide to go on the offensive. They have no choice.They can’t go home. It only delays the inevitable.The Ga’ee march relentlessly into the space of the seven races while turning an inward eye toward the interloper, the ship they call God1...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Overwhelming Force by Craig Martelle, Michael Anderle]()
Overwhelming Force by Craig Martelle, Michael Anderle
Rated: 4.67 of 5 stars · 6 ratingsThe keys to the universe……are hidden on two different planets, both at war. The Bad Company is the only force capable of unlocking destiny.Terry and Char take the Bad Company beyond the frontier, back to Benitus Seven. What they find shocks them to the very core of their beings.Marcie and Kae develop a new force, a land army to win the peace and keep it...Categorized as:
exploration military space-opera space-travel soldiers sci-fi fiction genetic-engineering -
![Raven's Flag by Glynn Stewart]()
Raven's Flag by Glynn Stewart
Rated: 4.57 of 5 stars · 7 ratingsIn times of peace, alliances wither and are forgotten.In times of war, honor must reforge them in fire and steel!The United Planets Alliance fought the Kenmiri Empire with a hundred allies at their side. Bound in common cause until genocide broke the Kenmiri—and Kenmiri schemes broke the alliance in turn—those one-time allies still left deep debts of blood and friendship behind... -
![Imperial Recruit by Terry Mixon]()
Imperial Recruit by Terry Mixon
Rated: 4.50 of 5 stars · 8 ratingsAndrea Tolliver—a genetically designed human from the Singularity—has finally earned a spot in the Imperial Marines. If she makes it through training, she’ll earn citizenship.If not—well, best not to think about that.With ruthless enemies willing to do anything to stop her, she’ll need all the help she can get to survive... -
![Guns of the Valpian by Anthony James]()
Guns of the Valpian by Anthony James
Rated: 4.50 of 5 stars · 8 ratingsCaptain John Duggan and his crew are stranded deep in hostile terrritory. Their spaceship, the ESS Crimson is damaged beyond repair. Enemy warships hunt them, eager to locate the vessel which has caused so much damage to their military. All seems lost. Duggan is not a man to go down without a fight... -
![Star Force: Origin Series by Aer-ki Jyr]()
Star Force: Origin Series by Aer-ki Jyr
Rated: 4.50 of 5 stars · 8 ratingsThe Origin Series is empire building at its finest, with 100 episodes and over 2.5 million words in the military science fiction serial detailing the rise of Star Force from corporate entity into an interstellar empire over the course of more than a millennium...Categorized as:
colonization exploration military space-opera space-travel action-adventure adult book -
![Explorations by Raymond L. Weil]()
Explorations by Raymond L. Weil
Rated: 4.50 of 5 stars · 8 ratingsDisaster has struck the Human Federation of Worlds. The Eternals have finally found Earth and are preparing to destroy it and the rest of the Federation. They begin gathering a massive fleet to overwhelm and destroy all of the Human worlds... -
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![Committed by Ell Leigh Clarke, Michael Anderle]()
Committed by Ell Leigh Clarke, Michael Anderle
Rated: 4.50 of 5 stars · 8 ratingsSean Royale is AWOL and in trouble. Molly’s Mom is encroaching on the operation on Gaitune. And the university is under threat from a new player in the system. Tensions mount as secrets unfurl, culminating in Molly walking down the aisle to try and save her ruggedly handsome friend... -
![Discovery by Craig Martelle, Michael Anderle]()
Discovery by Craig Martelle, Michael Anderle
Rated: 4.50 of 5 stars · 8 ratingsThe hero the universe needed and her friends.People who embrace justice as much as she does. Her people. One team, holding villainy at bay, even if they are demons from the past come back to haunt them all.A Queen. Two colonels. A contract that's too easy. A vacation gone awry. Enemies and allies.Terry and Char find themselves trapped.Here comes Bethany Anne. Here comes the Bad Company...Categorized as:
exploration military space-opera space-travel soldiers sci-fi fiction genetic-engineering -
![Junkyard Veterans by Jamie McFarlane]()
Junkyard Veterans by Jamie McFarlane
Rated: 4.53 of 5 stars · 17 ratingsWith a price on their heads, grumpy old vets will risk everything to bring alien assassins to justice.Someone is killing off the old team of vets who repelled Earth’s first Korgul invasion. With the end of a war precious few even knew was happening, life’s been peaceful... -
![Oblivion's Light by Raymond L. Weil]()
Oblivion's Light by Raymond L. Weil
Rated: 4.40 of 5 stars · 10 ratingsTwo more years have passed for the Lost Fleets trapped in the Triangulum Galaxy. It’s becoming more apparent with each passing day that the Dyson Sphere of the Simulins must be destroyed if Fleet Admiral Jeremy Strong and his people want to survive. Rear Admiral Kathryn Barnes sets out on a mission of discovery seeking allies against the Simulins... -
![Genesis by Raymond L. Weil]()
Genesis by Raymond L. Weil
Rated: 4.40 of 5 stars · 10 ratingsFleet Admiral Jeremy Strong is determined to preserve the planet Gaia as the new home of the lost fleets. Unfortunately, a new and frightening danger from the destroyed Dyson Sphere threatens to undo everything he has fought for. Kazak, the AI on the Originator ship has his own agenda. The Humans and Altons will either do as he demands or he will destroy them... -
![Star Force: Origin Series by Aer-ki Jyr]()
Star Force: Origin Series by Aer-ki Jyr
Rated: 4.40 of 5 stars · 10 ratingsThe Origin Series is empire building at its finest, with 100 episodes and over 2.5 million words in the military science fiction serial detailing the rise of Star Force from corporate entity into an interstellar empire over the course of more than a millennium...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Search for the Lost by Raymond L. Weil]()
Search for the Lost by Raymond L. Weil
Rated: 4.40 of 5 stars · 10 ratingsFrom USA Today Best Selling Author Raymond L. Weil comes the second book in the Originator Wars series. The Eternals have decided to conquer Originator space. All that stands between them are the Originator AIs and the Humans, or at least that is what the Eternals believe. In preparation for the invasion, they begin gathering their massive warfleet... -
![Return to Haven by D.J. Holmes]()
Return to Haven by D.J. Holmes
Rated: 4.40 of 5 stars · 10 ratingsThe revelation that the human race is not alone has sent shockwaves throughout Earth’s naval powers. Suddenly all eyes have turned to Haven and the trade routes to the Vestarian and Kulrean homeworlds. Thinking he has nothing to lose, Haven’s First Councilor puts into motion a plan that threatens to turn star empire against star empire...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![A King's Ship by D.J. Holmes]()
A King's Ship by D.J. Holmes
Rated: 4.40 of 5 stars · 10 ratingsThe war with China is over. But for Captain James Somerville there is a task still unfinished. Former Politburo Intelligence Minister Chang has evaded capture and escaped from Chinese space. Declared a war criminal by the UN and British law courts, James is given the Royal Space Navy’s newest exploration cruiser and sent after Chang... -
![Shell Game by J.N. Chaney, Terry Mixon]()
Shell Game by J.N. Chaney, Terry Mixon
Rated: 4.40 of 5 stars · 10 ratingsIf you can't hide the game, conceal the pieces. Admiral Jack Romanoff and his people have located the system the Tardans are using as their command post for the invasion of the Confederation. Only they can't simply attack militarily because of the stellar terrain, so they need to improvise. When the stakes are high, leave no option unexplored... -
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![Lightning Strike by J.N. Chaney, Terry Mixon]()
Lightning Strike by J.N. Chaney, Terry Mixon
Rated: 4.40 of 5 stars · 10 ratingsIn combat, speed is life.Admiral Jack Romanoff and his people have seized control of Faust and now have a base of operations, though the people of that world aren't completely pleased by his presence or actions. That's okay because he doesn't have time to worry about them. He needs to strike the Locusts before they spread even more than they already have in the wreck everything humanity has built... -
![Vigilance by Ken Lozito]()
Vigilance by Ken Lozito
Rated: 4.33 of 5 stars · 12 ratingsThey’ve spent years exploring this world, but they were living on borrowed time. Only they didn’t know it. Six months ago, Connor learned what the alien race that populated New Earth feared—a mysterious enemy who nearly brought about the collapse of an entire civilization. To help the colony prepare for this new threat, Connor rejoins the Colonial Defense Force... -
![Fracture by Ken Lozito, Scott Aiello]()
Fracture by Ken Lozito, Scott Aiello
Rated: 4.33 of 5 stars · 12 ratingsColonel Sean Quinn is stranded in another universe, along with two thousand people under his command. They've been hiding from the enemy long enough, now it’s time to return home. Outnumbered against a superior foe, Sean must risk everything in a daring operation, but the mysterious enemy has a few surprises of their own...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![The Lost Star Gate by Vaughn Heppner, Mark Boyett]()
The Lost Star Gate by Vaughn Heppner, Mark Boyett
Rated: 4.33 of 5 stars · 12 ratingsThe Swarm is coming!This time, enemy science vessels study us as Hive Masters gather hundreds of thousands of starships for an avalanche invasion.Instead of facing massed bug fleets in hopeless battle, we have a desperate plan: use a Builder nexus, create a hyper-spatial tube and send suicide-ships thousands of light-years into Swarm territory...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Emergence by Ken Lozito, Scott Aiello]()
Emergence by Ken Lozito, Scott Aiello
Rated: 4.29 of 5 stars · 14 ratingsAs the colony grapples with the realization that New Earth is not as uninhabited as they’d once thought, tensions between the colonial settlements rise to new heights, and the Colonial Defense Force finds itself caught in the middle. When Connor uncovers evidence of a militant colonial faction secretly exploiting the NEIIS, he has to investigate...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![The Others by Jay Allan]()
The Others by Jay Allan
Rated: 4.46 of 5 stars · 17 ratingsFrom the deepest darks of unknown space, evil comes… Admiral Tyler Barron and the Confederation navy face a new threat, darker and deadlier than any that have come before...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Dark Moon Arisen by Chris Kennedy, Mark Wandrey]()
Dark Moon Arisen by Chris Kennedy, Mark Wandrey
Rated: 4.50 of 5 stars · 6 ratingsThe war continues! The Omega War is in full swing. Earth has fallen to General Peepo’s army, and the surviving Human mercenaries have taken refuge at the hidden Winged Hussars’ base in New Warsaw...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Star Force: Temple Wars by Aer-ki Jyr]()
Star Force: Temple Wars by Aer-ki Jyr
Rated: 4.50 of 5 stars · 6 ratingshe bell has been rung, and the Return of the Reignor has come...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Hell's Reach by David VanDyke, B.V. Larson]()
Hell's Reach by David VanDyke, B.V. Larson
Rated: 4.50 of 5 stars · 6 ratingsUSA Today bestseller B.V. Larson and Dragon award finalist David VanDyke have released book six in their epic military space opera! The Breakers find a new home among the stars: Utopia. An engineered planet that is vast beyond comprehension with plenty of room to grow. They set up trade routes and work as mercenaries for their supplies… but trouble lurks. Pirates strike their merchant lanes... -
![Alpha Contracts by Chris Kennedy, Mark Wandrey]()
Alpha Contracts by Chris Kennedy, Mark Wandrey
Rated: 4.50 of 5 stars · 6 ratings“Before CASPers were the lords of the battlefield, men tested their metal against aliens one-on-one.” First contact has been made, and Earth’s militaries and its premier mercenary companies stand ready to take their first tentative steps outside the Solar System...Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
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![Maelstrom Strand by Rick Partlow]()
Maelstrom Strand by Rick Partlow
Rated: 4.50 of 5 stars · 6 ratingsSome enemies don’t get mad. They get even. Logan Conner and Wholesale Slaughter won the day on Revelation, but the Starkad Supremacy doesn’t like failure. If they can’t beat Sparta on the battlefield, they’ll make them fold from within...Categorized as:
colonization exploration military soldiers space-travel action-adventure adult audiobook -
![Judas Kiss by Rick Partlow]()
Judas Kiss by Rick Partlow
Rated: 4.50 of 5 stars · 6 ratingsThe battle for Sparta has begun. Logan Brannigan has taken back his father’s name and now he and Wholesale Slaughter fight to reclaim his father’s throne. But deposing the traitor, Rhianna Hale, without bringing all of Sparta into a bloody and divisive civil war won't be easy. And while the Spartans fight among themselves, vultures circle, waiting for their chance to claim what’s left... -
![Enemies & Allies by Rick Partlow]()
Enemies & Allies by Rick Partlow
Rated: 4.50 of 5 stars · 6 ratingsThe war is over and Andy Clanton is ready to live happily ever after.Space Force has other ideas.Recruited to follow the last signal of the mysterious Elders to a system halfway across the galaxy, Andy joins the crew of the James Bowie for another adventure into the unknown... -
![Zero Friction by Toby Neighbors]()
Zero Friction by Toby Neighbors
Rated: 4.50 of 5 stars · 6 ratingsThe bestselling space opera is back! The crew of the Modulus Echo is stuck in service to Brigadier General Alicia Pershing in exchange for their freedom. But while working for the Royal Imperium may have its perks, it is also extremely dangerous. From space battles to rescue missions, Ben and his friends will have to use all their resourcefulness if they hope to survive... -
![Star Force: Phoenix by Aer-ki Jyr]()
Star Force: Phoenix by Aer-ki Jyr
Rated: 4.50 of 5 stars · 6 ratingsCal-com's journey is not at an end. In fact, it's just beginning..Categorized as:
colonization exploration military soldiers space-opera space-travel action-adventure adult -
![Third Moon Chemicals: Adventures of a Jump Space Accountant Book 3 by Andrew Moriarty]()
Third Moon Chemicals: Adventures of a Jump Space Accountant Book 3 by Andrew Moriarty
Rated: 4.50 of 5 stars · 6 ratingsJake's back. He's not the best spy ever. He fails his pilot exam, he can't shoot, and he gets beat up a lot, usually by girls. Next task is to track containers of missing food. What could possibly go wrong? Next thing he knows he's on a strange ship with not one, but two pretty girls, helping them smuggle illegal workers to pirates...
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