Russia’s Soyuz launches Pion-NKS naval intelligence satellite

Russia launched the first satellite for its long-delayed next-generation ocean reconnaissance system on Friday. The Pion-NKS No.901 satellite lifted off atop a Soyuz-2-1b carrier rocket from the Plesetsk Cosmodrome in Northern Russia at 22:50 Moscow Time (19:50 UTC).

Pion-NKS is part of the wider Liana program, aimed at replacing the Soviet-era signals intelligence satellites which Russia previously used to collect and monitor radio signals from low Earth orbit. Pion replaces the Upravlenniye Sputnik – Passivny Modifikirovanny (US-PM) satellites used for naval reconnaissance, while the complementary Lotos-S satellites are replacing Tselina-2 spacecraft that were specialized for locating radio sources on land.

The Liana project grew out of a 1994 proposal, undergoing several redesigns over the years due to changes in technology and the political environment – the latter forcing the satellites to be downsized to fit on Soyuz rockets instead of the more capable, but Ukrainian-manufactured, Zenit.

The Pion spacecraft is equipped with both passive and active reconnaissance systems to aid in its mission to detect and track ships at sea. The passive component of the satellite’s payload consists of antennae which allow it to listen for radio signals and use these to assess the position of vessels. The active component will use radar to locate the vessels directly.

The prime contractor for Russia’s Liana program is the KB Arsenal design bureau, who also developed the instruments used aboard the satellites, and are responsible for integrating them into the completed spacecraft. Both Lotos-S and Pion-NKS are based around a platform that was derived from the Yantar series of reconnaissance satellites, with TsSKB Progress responsible for their manufacture.

Rendering of the Pion-NKS satellite – via KB Arsenal

While the first prototype Lotos-S satellite launched in 2009 and operational missions began in 2014, Friday’s launch marked the first flight of the Pion-NKS. Its deployment ends a gap in Russian naval intelligence-gathering capabilities that has existed since the last US-PM satellite, Kosmos 2421, failed shortly after launch in June 2006.

The Soviet Union began development of its naval reconnaissance satellites in the 1960s. For the first-generation system, the radar and signals intercept functions were split into two different satellites – named US-A and US-P respectively. The power requirements of the radar equipment on the US-A satellites led to a decision to equip the spacecraft with nuclear reactors, although the first six prototypes used batteries instead. The US-P satellites were powered by solar panels.

Thirty-two operational US-A spacecraft were launched between 1970 and 1998, while thirty-seven US-P satellites were deployed between 1974 and 1991, with all launches of both types using the Tsyklon-2 rocket. In the west, these satellites became known as Radar Ocean Reconnaissance Satellite (RORSAT) and Electronic Ocean Reconnaissance Satellite (EORSAT) respectively.

An upgraded version of the solar-powered US-P satellite, US-PM, replaced both previous series in 1993. Thirteen were launched – also using Tsyklon-2 rockets – with the last reaching orbit in June 2006. Despite a successful launch, one of the satellite’s solar panels failed to deploy properly. In March 2008, the satellite was reported to have disintegrated in orbit, producing over 500 catalogued pieces of debris.

Most of Russia’s military satellites are given official names of the word “Kosmos” – Russian for “Space” – followed by a sequential number. This practice began in 1962, and the series of Kosmos satellites has historically also included uncrewed test flights of the Vostok, Voskhod and Soyuz spacecraft, as well as failed interplanetary probes which found themselves stranded in Earth orbit.

Today these numbers are only used for military spacecraft. Since the designations are sequential, Pion-NKS No.901 is expected to become Kosmos 2560, assuming no previously-undisclosed satellites have been deployed from other military spacecraft in orbit since Russia’s last military launch in February.

The Pion satellite rode to orbit atop a Soyuz-2-1b carrier rocket. Soyuz-2-1b is the latest and most powerful version of the Soyuz rocket that has served Russia, and formerly the Soviet Union, since the 1960s.

Soyuz itself is a derivative of Sergei Korolev’s R-7 missile, which was the first intercontinental ballistic missile (ICBM) to fly, making its first launch in 1957. R-7 served as the basis for several closely-related families of rockets, including Vostok, Voskhod, Molniya and Soyuz – the latter of which is the only one that remains in service.

Three versions of Soyuz are currently in use, Soyuz-2-1a, 2-1b and 2-1v. Soyuz-2-1a was developed as a direct modernization of the previous-generation Soyuz-U, while Soyuz-2-1b introduces further upgrades to carry heavier payloads. The Soyuz-2-1v design features a redesigned and re-engined Blok-A core stage without the four distinctive boosters that make up the first stage of other Soyuz rockets, and is designed to carry smaller payloads at a lower cost.

A Soyuz-2-1b launches a GLONASS-K navigation satellite from Plesetsk in October 2020 – via Roscosmos

Soyuz-2-1a was the first of the three Soyuz-2 configurations to fly, making a suborbital test flight in November 2004 and an initial orbital launch in October 2006. The first Soyuz-2-1b launch was made in December 2006 with the French CoRoT space telescope as its payload. These versions slowly replaced the earlier Soyuz-U on military, commercial and ISS resupply launches, as well as Soyuz-2-1a replacing the interim Soyuz-FG for crewed launches. The last Soyuz-U was launched in February 2017, and Soyuz-FG followed it into retirement in September 2019.

The smaller Soyuz-2-1v was introduced in 2013, and is intended to replace smaller rockets in Russia’s fleet, such as Rokot, Kosmos-3M and Tsyklon.

Soyuz can launch from four different launch sites: the Baikonur Cosmodrome in Kazakhstan, the Plesetsk and Vostochny Cosmodromes in Russia, and the Guiana Space Center in Kourou, French Guiana. Friday’s launch took place from Plesetsk, which is Russia’s main launch site for military satellites.

While Plesetsk originally had four R-7 launch pads, only two are still in use with Soyuz-2. These are Pads 3 and 4 at Site 43.

Prior to launch, Soyuz was assembled horizontally in the integration hangar, or MIK, before being transported to the launch pad by rail. The rocket was then raised vertical and enclosed in the pad’s petal-like gantry structures. These allowed access to the vehicle and its payload while the vehicle was at the launch pad.

The three-stage Soyuz-2-1b rocket burned RG-1 propellant – the Russian designation for rocket-grade kerosene – oxidized by liquid oxygen. The first stage consisted of four boosters – Blok-B, V, G and D – clustered around the second stage, Blok-A. Each of the four boosters was powered by a single RD-107A engine. Blok-A had an RD-108A engine, a modification of the RD-107A incorporating vernier nozzles to help steer the rocket.

Close-up photo of the Soyuz-2-1b engines during the launch of 3 Gonets-M satellites in December 2020 – via Roscosmos

The first and second stages burned together during the early phases of ascent. The five engines ignited about sixteen seconds before liftoff, building up thrust as the clock ticked towards zero. With the engines at full thrust and the countdown at zero, the launch pad swing arms came open and Soyuz began to ascend.

First stage separation occurred around 118 seconds into the flight, with the four boosters venting residual oxygen through valves in their noses to push them away from the still-firing second stage. The “Korolev Cross” was formed in the sky by the four boosters falling away from the rocket, named after the rocket’s Chief Designer.

After staging, the second stage continued to burn for another 170 seconds. Towards the end of this burn, the rocket’s payload fairing separated.

The third stage used a “fire-in-the-hole” separation, igniting its RD-0124 engine while the second stage was still burning. The interstage between the two stages was designed to allow exhaust gasses to escape between ignition and stage separation. Shortly after staging, the third stage’s aft skirt was jettisoned, splitting into three pieces and falling away.

The third stage injected the Pion-NKS satellite into low Earth orbit. Spacecraft separation took place a few moments after third stage shutdown.

Friday’s launch was Russia’s ninth of 2021, all of which have used Soyuz rockets. It was Russia’s first military launch since February, when another Liana satellite – a Lotos-S1 – was deployed by another Soyuz-2-1b.

Roscosmos Director General Dmitry Rogozin recently admitted that Western sanctions against Russia had impacted the country’s space activities, particularly through a lack of availability of electrical components for satellites. This has contributed to Russia’s low flight rate, with four of the nine launches to date this year having exclusively carried commercial payloads.

(Lead photo from Gonets-M launch in December 2020 via Roscosmos)

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