# Fregat-MT > model of Russian rocket upper stage **Wikidata**: [Q15896716](https://www.wikidata.org/wiki/Q15896716) **Source**: https://4ort.xyz/entity/fregat-mt ## Summary The Fregat-MT is a model of a Russian rocket upper stage developed by NPO Lavochkin. As a subclass of the Fregat family of upper stages, it is designed to provide propulsion during the final phase of a launch. It is utilized by the Soyuz-2.1b rocket to deploy payloads into orbit. ## Key Facts * **Classification:** The Fregat-MT is a model of a rocket upper stage and a subclass of the Fregat family. * **Developer:** It was developed and is manufactured by NPO Lavochkin in Russia. * **Launch Vehicle:** It is used by the Soyuz-2.1b version of the Soyuz-2 rocket. * **Mass:** The stage has a dry weight of 1,035 kg and a launch weight of 7,640 kg. * **Dimensions:** It has a diameter of 3.8 meters and a height of 1.945 meters. * **Propulsion:** The main engine is the S5.92, supported by a reaction control system. * **Fuel:** The main engine utilizes 1,1-dimethylhydrazine and hydrazine, while the reaction control system is powered by hydrazine. ## FAQs ### Q: Who manufactures the Fregat-MT? A: The Fregat-MT is both developed and manufactured by NPO Lavochkin, a Russian aerospace company. ### Q: Which rocket uses the Fregat-MT upper stage? A: The Fregat-MT is used by the Soyuz-2.1b, which is a specific version of the Soyuz-2 rocket. ### Q: What are the physical specifications of the Fregat-MT? A: The upper stage has a diameter of 3.8 meters and a height of 1.945 meters. It weighs 1,035 kg when dry and 7,640 kg at launch. ### Q: What type of engine powers the Fregat-MT? A: It is powered by an S5.92 engine which runs on 1,1-dimethylhydrazine and hydrazine. ## Why It Matters The Fregat-MT upper stage plays a critical role in the Russian space program by serving as the "space tug" for the Soyuz-2.1b launch vehicle. Its primary function is to deliver payloads to their intended orbits after the main rocket stages have completed their burn. By separating from the booster and firing its own engine in the vacuum of space, the Fregat-MT allows for complex orbital insertions that the core rocket stages cannot achieve alone. Developed by NPO Lavochkin, this upper stage represents a specialized iteration of the broader Fregat family, optimized for specific payload capacities and mission profiles. Its engineering allows for a substantial propellant load relative to its dry mass—a ratio evidenced by its launch weight of 7,640 kg versus a dry weight of just 1,035 kg. This efficiency is essential for maximizing the payload mass that can be delivered to orbit, making the Soyuz-2.1b/Fregat-MT combination a significant asset for commercial and scientific satellite launches. The integration of the S5.92 engine and a dedicated reaction control system ensures precise maneuvering and orientation during these critical deployment phases. ## Notable For * **Subclass Design:** Being a distinct subclass of the Fregat family of upper stages. * **Propulsion Efficiency:** A high ratio of launch weight (7,640 kg) to dry weight (1,035 kg), indicating a high propellant capacity for orbital maneuvers. * **Specific Integration:** Its dedicated use with the Soyuz-2.1b launch vehicle. * **Engine Configuration:** Utilization of the S5.92 engine paired with a 12-unit reaction control system. ## Body ### Development and Origin The Fregat-MT is a Russian rocket upper stage model manufactured and developed by NPO Lavochkin. It originates from Russia and serves as a subclass of the wider Fregat family of upper stages. The Fregat family is a versatile group of space tugs used to deliver spacecraft to various orbits. ### Physical Characteristics The Fregat-MT possesses specific dimensions and mass properties optimized for the Soyuz-2.1b rocket: * **Height:** 1.945 meters * **Diameter:** 3.8 meters * **Dry Weight:** 1,035 kilograms * **Launch Weight:** 7,640 kilograms ### Propulsion Systems The upper stage relies on a bipropellant system for main propulsion and a monopropellant system for attitude control: * **Main Engine:** The stage is powered by the S5.92 engine. This engine utilizes a fuel mixture of 1,1-dimethylhydrazine and hydrazine. * **Reaction Control System (RCS):** For fine-tuning and orientation, the stage employs an RCS consisting of 12 units powered by hydrazine. ### Application The Fregat-MT is specifically cited as a component of the Soyuz-2.1b rocket. In this configuration, it acts as the final stage responsible for delivering the mission payload to its designated orbit. ## References 1. [Source](https://www.russianspaceweb.com/fregat.html) 2. [Source](https://space.skyrocket.de/doc_stage/fregat.htm) 3. [Source](https://www.laspace.ru/en/activities/products/sredstva-vyvedeniya/razgonnye-bloki-fregat-/)