“Shit,” Private Enzo cursed at the red blinking light on his Sentinel’s command console. “The missile launcher is jammed again.”
“Again?” Enzo’s lancemate, Corporal Fritz-McCarrol, maneuvered his Crab close to where Enzo’s Sentinel stood on the firing range and brought its cockpit to within a few meters of the Defiance Streak SRM-2’s exhaust port. “Doesn’t look broken to me.”
Enzo frantically flipped several switches and turned even more knobs, but the red light continued to blink tauntingly. “I don’t friggin’ know, Fritz. It’s the third time today. I don’t know how I’m supposed to qualify for live rounds if I can’t get a missile to come out of the damned tube.”
To onlookers, the two ‘Mechs then seemed to engage in a strange dance, where the Sentinel kept contorting itself in an attempt to clear the jam, while the Crab tried to peer into exhaust ports and heat sink vents to diagnose the problem. It was all in vain, and the Sentinel eventually straightened, then slumped its shoulders as its pilot mentally admitted defeat.
“The hell are you two doing?” Lieutenant Silva’s bewildered voice inquired from the firing range’s protected observation tower.
The Crab pointed to the Sentinel’s chest. “His launcher’s jammed,” said Corporal Fritz.
“Again?”
“Yes sir,” the two MechWarriors groaned.
Lieutenant Silva rubbed the bridge of her nose. Private Enzo was the newest member of her lance, and as expected, he had a lot to learn about the weapons he would soon be employing on behalf of the Star League Defense Force. The first and most valuable lesson was that Star League Procurement didn’t always provide the most reliable tools. The second and equally valuable lesson was to enact field repairs quickly with whatever was currently available.
“Have you tried hitting it?” She suggested. “Works on the tri-vid player.”
The Crab and the Sentinel looked at each other for a moment. “No sir,” Enzo said.
“Try it,” then the radio crackled as Lieutenant Silva changed frequencies to explain to the range officer why two of her ‘Mechs were standing on the range without firing.
Fritz placed his Crab’s hand over the Sentinel’s Streak missile launcher like a carpenter readying a nail as he balled the ‘Mech’s other hand into a fist. “How hard do you think I should hit you?”
Enzo brought his Sentinel’s arms up and pushed the Crab away before it could strike. “You shouldn’t! At least not there. That’s the launcher. The ammo feeder is more in this area.” Enzo brought the Sentinel’s hand up and made a small circle over his ‘Mech’s right breast. Or at least, where it might have been if the Sentinel had a more humanoid torso.
Without warning, Corporal Fritz brought his Crab‘s first down onto the Sentinel’s torso in roughly the area indicated. Enzo’s damage display revealed armor had been shattered over the impact area, but the red light continued to blink stubbornly. “Try it again.”
Another impact, harder than the last, shook Enzo around in his cockpit. More armor had been shattered under the Crab‘s fist, yet still, the red light blinked. “One more time.”
This time, the Crab‘s fist missed and put its knuckle straight through the Sentinel‘s ferroglass cockpit, but luckily not far enough to crush its pilot. Enzo’s neurohelmet protected his face from the many shards of ferroglass that came pouring over him, but the rest of him was clad in the SLDF’s standard-issue cooling vest and shorts, which offered much less protection.
“Uh, whoops?” Fritz offered. Enzo didn’t reply. He couldn’t; his radio had been smashed by the Crab‘s finger. But he did note with some satisfaction that the red light on his mangled command console had finally gone dark.
While BattleMechs would reign as the king of the modern battlefield ever since the Mackie, infantry remains the backbone of most militaries. Protecting infantry from the tyranny of ‘Mechs became an increasingly difficult task throughout the 25th century, and by the 27th century, the Great Houses were requesting dedicated infantry support ‘Mechs.
Before the SLDF had even thought to demand a dedicated infantry support BattleMech, the Lyran Commonwealth contracted Defiance Industries to produce just such a machine in 2651. Unfortunately for the LCAF, Defiance Industries’ board of directors was controlled by the Terran Hegemony, who informed Star League procurement of a new ‘Mech with a rather unique mission profile. The Star League charter prevented any House army from obtaining new weapons before the Star League Defense Force, which led Defiance Industries to produce two versions of the Sentinel in 2652: the STN-3L for the Star League Defense Force, and the STN-1S for the Lyran Armed Forces. The STN-3L was armed with state-of-the-art weapons largely unavailable to the Great Houses, while the STN-1S made do with technology that was already several generations old.
The SLDF jumping military procurement orders to ensure Terran Hegemony dominance was hardly new by the 2600s, and it would be several years before the Lyran Commonwealth would argue its way to an upgrade package that brought its STN-1S Sentinels up to the STN-3L standard. However, by then the Star League had accepted deliveries of the STN-3Lb model, which made all previous Sentinels obsolete.
Being first in line for every new ‘Mech did produce some issues for the Star League. In the Sentinel‘s case, initial production models would consistently overheat during field maneuvers even if they weren’t strenuously engaged. Star League technicians first blamed the problem on faulty Pitban 240 fusion engines, but later analysis revealed a design error in the Sentinel‘s 10 single heat sinks reduced their heat dissipation well below their expected cooling rate.
The heat sink issue was resolved relatively quickly with Defiance providing a free refit package and redesigning its future production.
Another problem that would take longer to fix was an issue with the Defiance Streak SRM-2‘s automatic reloader. Defiance had swapped the Defiance A-1 Small Laser on pre-production models for the Defiance B-1A model, which was more robust but also necessitated moving the missile feed mechanism by half a meter. If the pilot were maneuvering the Sentinel at its top speed of 97.2 kph it could cause missiles to shift position in the belt and block the feeder. Sentinel pilots quickly learned that jostling the loader could clear the jam, which was best performed by slamming the Sentinel‘s right fist against its chest.
However, this solution presented a new problem for Sentinel pilots. Opposition forces quickly learned to target Sentinel pilots slamming their chest as it meant an ammunition jam, forcing Sentinel pilots to retreat from the front line before attempting to clear the jam.
Ironically, it was the Succession Wars that eventually solved the Sentinel‘s missile loader issue. As Streak missiles became Lostech during the Succession wars, Defiance Industries was forced to produce the downgraded STN-3K variant which instead used a standard SRM launcher less prone to jamming.
The original STN-3L came equipped with some of the most advanced weapons the Star League could produce. A Kawabata Weapons Industries Ultra Autocannon/5 accompanied a Defiance Streak SRM-2 launcher to provide adequate support for infantry in almost any battlefield scenario. A single Small Laser gave the Sentinel another anti-infantry weapon not reliant upon ammunition. A Pitban 240 engine gave the Sentinel a speed of 97.2 kph, which was deemed more than sufficient for fast response on the front lines. Ten heat sinks kept the ‘Mech cool in all but the most dire battlefield conditions, and 5.5 tons of Valiant Lamellor standard armor gave the pilot decent protection. A StarLink/Benicia Model AS829G communications package allowed the Sentinel to maintain comms with multiple units, making it an excellent choice for a sub-commander overseeing infantry maneuvers.
By contrast, the Steiner’s STN-1S came armed with a Defiance Model F Autocannon/2 and a Coventry Quad-Rack SRM-4—both easier to procure but far less potent than the STN-3L’s armament. The 1S models would all eventually be upgraded to the 3L, but not before the Star League Royal STN-3Lb put the initial 3L to shame. No expense was spared on the 3Lb, with an Extralight engine and endo steel chassis offering enormous weight savings and seven tons of ferro-fibrous armor providing ample protection for a 40-ton ‘Mech. Its armament of a single Gauss rifle, Medium Laser, and Small Laser gave the 3Lb a potent punch for its size.
Defiance Industries would remain remarkably untouched throughout the dark days of the Succession Wars, but as the Inner Sphere‘s technology decayed, Defiance found itself unable to procure either Ultra Autocannons or Streak missiles. This led to the downgraded STN-3K model. Armed with a Defiance Type J AC/5 and a Holly SRM-2 rack, the STN-3K was actually somewhat more durable than the 3L with six tons of standard armor and even had an extra ton of ammunition for its autocannon. This proved fortuitous as Succession Wars supply lines were rarely stable, which gave us both the STN-3KA and STN-3KB models. The 3KA replaced the autocannon with a Large Laser, three more heat sinks, and two tons of additional armor, while the 3KB replaced it with a PPC and three heat sinks.
No new Sentinel variants were produced until the War of 3039 and the STN-3M. Supplied by ComStar to the DCMS as part of Operation ROSEBUD, the STN-3M retains the Ultra AC/5 but uses a standard SRM-2 and Magna Mk II Medium Laser over the original Small Laser. House Kurita was initially pleased with the “new” design but later soured after learning the Streak missile launcher had been replaced by one manufactured by the Magistracy of Canopus. Even still, the 3M proved effective against confounded Davion forces facing advanced munitions for the first time in centuries.
The Sentinel would see a slight resurgence following the Clan Invasion. Many STN-3M models would be upgraded to the STN-C standard, removing the medium laser for access to C3 networks. Davion Sentinels saw their Ultra Autocannons removed for a then-new Rotary Autocannon, an Extended-Range Medium Laser, and seven tons of ferro-fibrous armor. During the Word of Blake‘s occupation of Hesperus, Defiance Industries produced the STN-5WB model. Equipped with a weight-saving light engine, it was equipped with two Light Autocannon/5s (albeit with a single ton of ammo between the two of them) and three ER Medium Lasers. In the modern era, the STN-6S leverages Defiance Industries’ access to Clan-spec technology, including a Clan 240 XL engine and a Clan ER Medium Laser. It’s still armed with an Inner Sphere-grade Ultra AC/5 but replaces the Streak launcher with two Thunderbolt 5 launchers.
One could argue that the most modern iteration of the Sentinel is in response to the proliferation of modern battle armor—something that previous versions didn’t have to contend with. The current STN-6S and even older 3L models provide adequate support to combined arms formations, but the Sentinel finds itself competing in an increasingly crowded market.
And as always, MechWarriors: Stay Syrupy.