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The Lotos series \u2013 of which six have launched \u2013 form a replacement for Soviet-era Tselina and US-PM surveillance satellites. Since the 1990s, the Liana Program has aimed to bring upgraded and more-capable reconnaissance and intelligence spacecraft into Russia\u2019s arsenal, via Lotos and Pion satellites.<\/p>\n
Lotos satellites will specifically replace the Tselina-2 series \u2013 launched beginning in the 1980s for over two decades \u2013 with the specific purpose of electronic signals intelligence (ELINT). This involves intercepting radio signals and relaying collected information for military analysis.<\/p>\n
Thursday\u2019s Lotos-S1 No. 5 joins a network of five other Lotos satellites, two of which are Lotos-S, the developmental version of the spacecraft launched in 2009 and 2014. The remaining Lotos-S1 satellites are the operational variant, having been launched starting in 2017. N\u00b0806 is the first of a new batch of Lotos-S1 satellites ordered by Russia\u2019s Ministry of Defence in September 2017, with a further three to be launched.<\/p>\n
Lotos spacecraft are based on the Yantar satellite bus built by TsSKB Progress, providing onboard power and propulsion. The reconnaissance technology \u2013 which is implemented onto the bus \u2013 is built by the KB Arsenal Design Bureau, which acts as the prime contractor for the Liana Program.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2021\/02\/russia-to-launch-its-latest-electronic-warfare-satellite1419438659.jpg\")
<\/p>\nIllustration of Lotos-S1 (left) and Pion-NKS (right), the latter of which is a signal-intercepting satellite of a similar design. (Credit: KB Arsenal Design Bureau)<\/p>\n
With Lotos-S1 No. 5 in orbit, it has been publicly renamed and numbered into the \u2018Kosmos\u2019 nomenclature for obscurity, as is standard with Russian military payloads since the 1960s. Lotos-S1 No. 5 is Kosmos-2554.<\/p>\n
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Since the retirement of Soyuz-U, Lotos-S1 satellites have been launched on an upgraded version of Russia\u2019s workhorse rocket, Soyuz 2.1b.<\/p>\n
Soyuz is an evolution of the Soviet R-7 vehicle, originally designed by Sergei Korolev as the world\u2019s first Intercontinental Ballistic Missile (ICBM) \u2013 debuting in 1957. Over decades of improvements and a considerable number of flights, Soyuz-2 culminates this evolution.<\/p>\n
Soyuz 2.1b is a medium-lift launch vehicle composed of three stages in default. Four strap-on boosters surround the core \u2013 known as the second stage \u2013 equipped with RD-107A engines. The second stage utilizes the closely-related RD-108A engine. Both engines run on RG-1 fuel \u2013 a refined type of petroleum similar to RP-1 \u2013 and liquid oxygen (LOX) as the oxidizer. As is common with many Soviet-originated engines, both the RD-107A and RD-108A utilize four main combustion chambers.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2020\/09\/1AB17EA3-2E03-4434-A738-141B2F3B514B-scaled.jpeg\")
<\/p>\nA Soyuz 2.1b rocket for a previous mission rolls out to Site No. 43 at the Plesetsk Cosmodrome. (Credit: Exolaunch)<\/p>\n
Due to a lack of Thrust Vector Control (TVC) with non-gimbaling nozzles, additional combustion chambers are used for roll control in the form of vernier thrusters. For guidance, Soyuz-2 features a digital system, being a notable improvement over the analog system of previous Soyuz variants.<\/p>\n
The third stage \u2013 Blok-I \u2013 utilizes the RD-0124, also running off RG-1\/LOX with four combustion chambers. A notable lack of an enclosed interstage structure between the second and third stages means that Blok-I ignites its RD-0124 whilst the second stage is still running \u2013 known as \u2018hot staging\u2019 \u2013 to avoid the need for ullage motors to settle propellants after stage separation.<\/p>\n
Another distinctive feature of the vehicle is the separation mechanism of the four strap-on boosters, which do so in a formation known as the \u2018Korolev Cross\u2019 \u2013 named after the R-7\u2019s chief engineer. The four boosters\u2019 LOX vents open at separation, pushing them away from the second stage in a uniform formation.<\/p>\n
Soyuz-2 utilizes the ST-type fairing made from aluminum and carbon fiber with a range of sizes and shapes available depending on payload characteristics.<\/p>\n
At launch, the command to begin the ignition sequence on the RD-107A and RD-108A is sent at T- 16 seconds. Following stable combustion, the swing arms retract from the vehicle at liftoff.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2021\/08\/Soyuz.jpg\")
<\/p>\nView of RD-107A and RD-108A engines powering a Soyuz-2 at liftoff. (Credit: Roscosmos)<\/p>\n
Using a typical Soyuz 2.1b mission profile, the four strap-on boosters exhaust their propellant and are jettisoned at around T+ 1 minute 58 seconds. Fairing separation occurs at approximately three and a half minutes into the flight, with the core second stage shutting down around T+ 4 minutes 48 seconds. Following hot staging, the third stage continues burning for the required amount of time per the desired payload-specific orbital parameters at deployment.<\/p>\n
Soyuz-2 is able to launch from four launch sites. In Russia, the first such site is Plesetsk Cosmodrome, located around 800 kilometers north of Moscow. This serves primarily as a site from which Russian military payloads are launched. In the Russian Far East, Soyuz is also launched from Vostochny Cosmodrome\u2019s Site 1S. The rocket can also launch from Baikonur Cosmodrome in Kazakhstan, carrying both crewed and uncrewed payloads.<\/p>\n
Soyuz vehicles were also launched from the Europe-led Centre Spatial Guyanais in Kourou, French Guiana. However, following the 2022 Russian Invasion of Ukraine, this is no longer the case per European sanctions and condemnation.<\/p>\n
(Lead image: A previous Soyuz rocket lifts off from the Plesetsk Cosmodrome. Credit: Russian Ministry of Defense.)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"
A Soyuz 2.1b rocket has successfully launched from the Plesetsk Cosmodrome, carrying a Lotos electronic signals intelligence satellite into orbit for the Russian military. Liftoff took place at 11:20 UTC from Plesetsk\u2019s Site 43 on a northeastern trajectory. Lotos-S1 number 5 was deployed into Low Earth Orbit with a separation apogee of approximately 900 km […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[8514,7961,1302,3080,3923],"class_list":["post-24650","post","type-post","status-publish","format-standard","hentry","category-news","tag-lotos","tag-plesetsk","tag-soyuz","tag-soyuz-2-1b","tag-soyuz-2"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24650"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=24650"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24650\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=24650"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=24650"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=24650"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}