Decoding the Lethal Upgrade in Russia’s Latest Su-57 Deliveries

A Su-57 from the batch delivered on February 9, 2026

On February 9, 2026, Russia's UAC delivered a large batch of Su-57s which, according to a UAC press release, were “in a new technical configuration.”

“The aircraft have received upgraded onboard systems and a new weapons complex.”

According to a TASS report that quoted experts, one of the main changes in the modernized Su-57 aircraft is the upgraded 101KS onboard optical-electronic self-defense system.

The new 101KS has an infrared channel, believed to operate in the medium and long-wave ranges, in contrast to the system of the previous batches. 

101KS Atoll Electro-Optical (EO) System

The 101KS Atoll Electro-Optical (EO) system is designed primarily for complete situational awareness. The system additionally assists the pilot in operation of the aircraft at all stages. It is used for air-to-air and air-to-surface target engagement, piloting & landing, and as a defensive suite.

The 101KS is a passive sensor suite that emits no radiation - IR or RF - thus providing the Su-57 with increased stealth and survivability. 

The suite includes the 

1. 4 x 101KS-U Omnidirectional UV based MAWS (U/01 - Dorsal aft & Ventral aft; U/02 Either side behind cockpit)

2. 2 x 101KS-O: DIRCM Laser-based counter-measures against infrared missiles (Dorsal fore, Ventral behind cockpit)

3. 101KS-P: Opto-electronic sensor

4. 101KS-V: Omnidirectional IRST for airborne targets

5. 101KS-N: Targeting pod

IRST 101KS-V

IRST is installed atop the aircraft's nose, near its windscreen. Photo: UAC Russia

The Su-57 sports an advanced infrared search and track sensor in the traditional position on Russian fighters—installed atop the aircraft's nose, near its windscreen. The positioning adversely impacts front aspect stealth of the aircraft but the ability of IRST to passively engage stealth aircraft from increasingly greater distances makes up for the LO erosion.

101KS-V forward looking IRST

The fore sensor suite on the Su-57 with elements of the N036 AESA and Atoll EO System

101KS-O, 101KS-U

Like the F-22, the Su-57 has a number of missile launch detector apertures scattered around the aircraft but the Su-57 also has turrets that fire modulated laser beams at an incoming missile's seeker to blind it and throw it off course. The IRST, and DIRCM turrets are mounted dorsally behind the cockpit and ventrally under the cockpit. 

Upper and lower 101KS-O bubbles are visible in the photo at the top.

The 101KS-O turrets on the Su-57 duplicate the functionality of the 101KS-V Opto-electronic (IRST) unit placed ahead of the cockpit but additionally feature IR homing suppression laser to blind an attacking missile providing DIRCM.

The 101KS-O system consists of two laser-emitting turrets, with one placed behind the cockpit on the dorsal side, and the other beneath the cockpit on the ventral side.

The Su-57 is the first fighter in the world to feature a DIRCM. Hitherto, the system has only been used on transports and helicopters only, invariably placed on the ventral side in the past as defense against MANPADS. The use of DIRCM to blind an air-to-air missile is unprecedented.

101KS-O turret on display at MAKS 2019

101KS-O turret on display at MAKS 2019

The 101KS-U MAWS UV sensors (below) of the Su-57 Atoll detect approaching IR missiles and the 101KS-O DIRCM blinds their IR homing sensors with laser.

101KS-U MAWS sensors on the Su-57

101KS-P Thermal Imager

The 101KS-P high resolution thermal imager of the Su-57 Atoll is installed on the wing leading edge & provides low altitude piloting and landing at night

101KS-P Thermal Imager

101KS-N Targeting Pod

101KS-N Optical Pod

The 101KS-N is a multi-channel optical sighting system designed to detect, identify and engage ground targe. The pod features its own thermal stabilization system. 

Situational Awareness

According to First Deputy Igor KRET Nasenkov, the Su-57 features a smart skin that provides the pilot 360-deg situational awareness.

The term "smart skin" refers to the fact that many of the surface of the aircraft are versatile antenna systems that facilitate integrated use of all resources of the aircraft. 

S-71 Integration

Since the UAC press release talks of a new weapons complex, it is possible that the fresh batch of Su-57s delivered is capable of carrying the newly developed air-launched stealthy combat UAV designated S-71, a weapon first unveiled during Army 2024.

The S-71 is an air-launched UAV that can be tasked with target identification, marking, or destruction. Deploying and controlling the Su-57 would require an upgrade of onboard systems. 

The S-71 began captive-carry trials in April 2024 at Russia’s Flight Research Centre in Zhukovsky, with test flights involving the Su-57 fighter.

You can read more details about the S-71 at my Thumkar blog post here.

On January 17, 2026, it was reported that an S-71K “Carpet” for the first time demonstrated its effectiveness by successfully destroying the highly mobile M142 HIMARS multiple launch rocket system.

The cruise missile–drone hybrid has been developed by GosMKB Raduga JSC and can be used by 4++ generation multirole fighters, including the Su-35S, Su-30SM/SM2, as well as Su-34 NVO fighter-bombers.