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37-608: The KTDU-80 system integrates a dual string redundant propellant and pressurization system, a main propulsion system (the SKD ), an RCS (the DPO-B ) and an attitude control system (the DPO-M ). All the propulsion elements are pressure fed rocket engines burning UDMH and N 2 O 4 with a common supply of pressurized propellant. Mechanically, the KTDU-80 is separated in two sections: Each subsystem

74-572: A bipropellant in combination with the oxidizer nitrogen tetroxide and less frequently with IRFNA (inhibited red fuming nitric acid) or liquid oxygen . UDMH is a derivative of hydrazine and is sometimes referred to as a hydrazine. As a fuel, it is described in specification MIL-PRF-25604 in the United States. UDMH is stable and can be kept loaded in rocket fuel systems for long periods, which makes it appealing for use in many liquid rocket engines, despite its cost. In some applications, such as

111-476: A hydrogen peroxide monopropellant which turned to steam when forced through a tungsten screen, and the Gemini thrusters used hypergolic mono-methyl hydrazine fuel oxidized with nitrogen tetroxide . The Gemini spacecraft was also equipped with a hypergolic Orbit Attitude and Maneuvering System , which made it the first crewed spacecraft with translation as well as rotation capability. In-orbit attitude control

148-539: A few spacecraft, including the ISS , use momentum wheels which spin to control rotational rates on the vehicle. The Mercury space capsule and Gemini reentry module both used groupings of nozzles to provide attitude control . The thrusters were located off their center of mass , thus providing a torque to rotate the capsule. The Gemini capsule was also capable of adjusting its reentry course by rolling, which directed its off-center lifting force. The Mercury thrusters used

185-475: A mixture of 50% hydrazine and 50% UDMH, called Aerozine 50 , in different stages. There is speculation that it is the fuel used in the ballistic missiles that North Korea has developed and tested in 2017. Hydrazine and its methyl derivatives are toxic but LD50 values have not been reported. It is a precursor to dimethylnitrosamine , which is carcinogenic. According to scientific data, usage of UDMH in rockets at Baikonur Cosmodrome has had adverse effects on

222-507: A mixture. UDMH is used in many European, Russian, Indian, and Chinese rocket designs. The Russian SS-11 Sego (aka 8K84) ICBM, SS-19 Stiletto (aka 15A30) ICBM, Proton , Kosmos-3M , R-29RMU2 Layner , R-36M , Rokot (based on 15A30) and the Chinese Long March 2 are the most notable users of UDMH (which is referred to as "heptyl" (codename from Soviet era ) by Russian engineers ). The Titan , GSLV , and Delta rocket families use

259-592: A more efficient and storable propellant UDMH and N 2 O 4 , which improved performance further. The reentry capsule attitude control system, still uses catalytic decomposition of H 2 O 2 , but that is a completely separate system. For this version of the KTDU, they used the pressure fed cycle for all rocket engines, and consolidated propellants on the UDMH/N 2 O 4 combination, which gives superior density and specific impulse and can be stored for years in space. For

296-436: A partial set of 11D428A-16. By Progress M-39 it flew with a full set of 11D428A-16, and finally Soyuz TM-28 marked the debut of the switch to 11D428A-16 for the crewed craft, which meant a saving of 30 kg (66 lb). The International Space Station experience brought some further changes. Experience had shown that during docking operations, only two DPO-B were available for abort operations. Thus, on October 23, 2002

333-490: A project was formally started to add two additional DPO-B, which brought the total number of high thrust DPO engines to 16. Soyuz TMA-5 was the first spacecraft to fly with this new configuration. With Soyuz TMA-11M debuted a new arrangement of the DPO-B thrusters. But this is a spacecraft specific configuration and does not mean any changes to the KTDU-80 per se. The new Soyuz-MS and Progress-MS spacecraft have an evolution of

370-455: A separated orbital correction system ( KTDU-35 ) from its orientation system. The latter, integrated a reaction control system called DPO and the attitude control system, called DO . The KTDU-35 had a main orbit correction engine SKD , the S5.60 and a backup orbital correction engine DKD , the S5.35 . These two were gas generator engines burning UDMH and AK27I . The DPO and DO thrusters, on

407-489: A set of twelve hypergolic thrusters for attitude control, and directional reentry control similar to Gemini. The Apollo Service Module and Lunar Module each had a set of sixteen R-4D hypergolic thrusters, grouped into external clusters of four, to provide both translation and attitude control. The clusters were located near the craft's average centers of mass, and were fired in pairs in opposite directions for attitude control. A pair of translation thrusters are located at

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444-456: A single one, or to use both systems independently. The Helium is stored initially at 34.32 MPa (4,978 psi) and is regulated to 1.75 MPa (254 psi), with a maximum pressure of 2.15 MPa (312 psi) and a minimum of 1.37 MPa (199 psi), which is the minimum required pressure to activate the pneumatically actuated valves of the SKD. The propellant supply subsystem function

481-448: Is a chemical compound with the formula H 2 NN(CH 3 ) 2 that is primarily used as a rocket propellant . At room temperature, UDMH is a colorless liquid, with a sharp, fishy, ammonia-like smell typical of organic amines . Samples turn yellowish on exposure to air and absorb oxygen and carbon dioxide . It is miscible with water, ethanol , and kerosene . At concentrations between 2.5% and 95% in air, its vapors are flammable. It

518-603: Is a spacecraft system that uses thrusters to provide attitude control and translation . Alternatively, reaction wheels can be used for attitude control. Use of diverted engine thrust to provide stable attitude control of a short-or-vertical takeoff and landing aircraft below conventional winged flight speeds, such as with the Harrier "jump jet" , may also be referred to as a reaction control system. Reaction control systems are capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS

555-674: Is also capable of providing torque to allow control of rotation ( roll, pitch, and yaw ). Reaction control systems often use combinations of large and small ( vernier ) thrusters, to allow different levels of response. Spacecraft reaction control systems are used for: Because spacecraft only contain a finite amount of fuel and there is little chance to refill them, alternative reaction control systems have been developed so that fuel can be conserved. For stationkeeping, some spacecraft (particularly those in geosynchronous orbit ) use high- specific impulse engines such as arcjets , ion thrusters , or Hall effect thrusters . To control orientation,

592-424: Is described in the following sections. The Pneumatic Pressurization System has three main functions: The system has four spherical pressurizing gas tanks in two separated circuits. Each circuit connects two tanks, and has its individual pressure transducer, valves, pressure regulator and electrically actuated valves. The circuits are separated by two squib actuated valves that enable to share both circuits, to use

629-670: Is not sensitive to shock. Symmetrical dimethylhydrazine (1,2-dimethylhydrazine) also exists, but it is not as useful. UDMH can be oxidized in air to form many different substances, including toxic ones. In 1875, UDMH was first prepared by Emil Fischer , who discovered and named the class of hydrazines , by reducing N-Nitrosodimethylamine with zinc in boiling acetic acid . Fischer's student Edward Renouf later studied UDMH more extensively as part of his doctoral dissertation. Other historical lab routes include methylation of hydrazine , reduction of nitrodimethylamine and amination of dimethylamine with aminopersulfuric acid. UDMH

666-493: Is produced industrially by two routes. Based on the Olin Raschig process , one method involves reaction of monochloramine with dimethylamine giving 1,1-dimethylhydrazinium chloride: In the presence of suitable catalysts, acetylhydrazine can be N-dimethylated using formaldehyde and hydrogen to give the N,N-dimethyl-N'-acetylhydrazine, which can subsequently be hydrolyzed: UDMH is often used in hypergolic rocket fuels as

703-441: Is to guarantee the supply of propellant within the required operating parameters of the engines. It uses two tanks of fuel and two of oxidizer in two separate circuits. It is separated into three propellant feed circuits: The first and second DPO circuits are connected through electro-hydraulic actuated valves that enable the transfer of propellant between line in case of failure of one pressurization or propellant storage circuit. So

740-505: The 11D427M , an uprated version of the 11D427 that increased thrust to 26.5 N (6.0 lbf). But due to manufacturability issues, those were later changed (by Soyuz TM-23 ) to the S5.142 (manufacturer's name DST-25 ). Since the S5.142 lack a pressure transducer on its main combustion chamber, the avionics had to be modified. On the other hand, this change enabled the DPO-B to keep the PAO away from

777-645: The KTDU-426 . One advantage of this system is that since the DPO could be used as backup of the main propulsion for orbit correction and de-orbit maneuvers, there was no need of adding a backup main propulsion (the DKD S5.35 in the previous system). But more importantly they could implement more extensive redundancy while keeping the mass of the system down. And by switching all the engines to the same propellant, all reserves could be consolidating reducing mass further. They also switched to

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814-468: The NF-104 AST , both intended to travel to an altitude that rendered their aerodynamic control surfaces unusable, established a convention for locations for thrusters on winged vehicles not intended to dock in space; that is, those that only have attitude control thrusters. Those for pitch and yaw are located in the nose, forward of the cockpit, and replace a standard radar system. Those for roll are located at

851-399: The KTDU-80. Now all 28 thrusters are the high thrust DPO-B, arranged in 14 pairs. Each propellant supply circuit handles 14 DPO-B, with each element of each thruster pair being fed by a different circuit. This provides full fault tolerance for thruster or propellant circuit failure. This engine has had two main variations: Reaction control system A reaction control system ( RCS )

888-518: The OMS in the Space Shuttle or maneuvering engines , monomethylhydrazine is used instead due to its slightly higher specific impulse . In some kerosene-fueled rockets, UDMH functions as a starter fuel to start combustion and warm the rocket engine prior to switching to kerosene. UDMH has higher stability than hydrazine, especially at elevated temperatures, and can be used as its replacement or together in

925-497: The de-orbit maneuver, which eliminated the need for the backup de-orbit engine (the DKD), further simplifying the system. For the low thrust attitude control system (DPO-M), they used the new 11D427. The number of engines was increased from 8 to 12, and thrust augmented from 14.7 N (3.3 lbf) to 24.5 N (5.5 lbf). The introduction of the Soyuz-TM in 1986 saw a new revision of

962-466: The orbital correction engine (SKD), they developed the 11D426 . That while less powerful than the S5.60 (3.09 kN (690 lbf) versus 4.09 kN (920 lbf)), it improved efficiency with a specific impulse of 292 seconds (the S5.60 had 278s). Also, the switch to pressure fed cycle eliminated the use of turbopumps and its associated cost and reliability issues. And it also enabled the reduction in minimum burn time and engine transients since there

999-490: The other hand, were monopropellant pressure fed rockets that used catalytic decomposition of H 2 O 2 to generate thrust. Having such dissimilar systems with different cycles, propellant, and feed systems added failure modes and required heavy backup equipment, like the backup de-orbit engine, the S5.35. For the Soyuz-T (first flight during 1979), Isayev 's OKB-2 developed for TsKBEM an integrated propulsion system,

1036-459: The propellant supply has redundant circuits. The S5.80 generates 2.95 kN (660 lbf) of thrust with a chamber pressure of 0.88 MPa (128 psi) and a nozzle expansion of 153.8 that enables it to achieve a specific impulse of 302 s (2.96 km/s). It is rated for 30 starts with a total firing time of 890 seconds. The berthing and attitude control thruster subsystem is composed of two types of thrusters: The original Soyuz had

1073-690: The propulsion system, the KTDU-80 . It was an evolutionary revision of the KTDU-426 system, rather and a revolutionary transition like the one done from the KTDU-35. The propellant supply subsystem switched to metallic diaphragms for the tank pressurization. The SKD main engine was changed to the new S5.80 . While slightly less powerful than the 11D426 with 2.95 kN (660 lbf), specific impulse increased to 302 s (2.96 km/s) and total burn time increased from 570 seconds to 890. The low thrust DPO-M initially used

1110-465: The rear of the Soyuz spacecraft; the counter-acting thrusters are similarly paired in the middle of the spacecraft (near the center of mass) pointing outwards and forward. These act in pairs to prevent the spacecraft from rotating. The thrusters for the lateral directions are mounted close to the center of mass of the spacecraft, in pairs as well. The suborbital X-15 and a companion training aero-spacecraft,

1147-448: The reentry capsule after separation. The high thrust DPO-B system initially kept the 11D428A used on the KTDU-426. Since the DPO-B also act as the backup engine for the main SKD, they always have to keep a reserve of propellant in case of SKD failure that is dead weight. Thus a project to develop a more efficient version, the 11D428A-16 was started in 1993. During a series of flights ( M-36 , M-37 and M-38 ) Progress-M flew with

KTDU-80 - Misplaced Pages Continue

1184-413: The same location, provided aft translation, and two 100-pound-force (440 N) thrusters located in the aft end of the adapter module provided forward thrust, which could be used to change the craft's orbit. The Gemini reentry module also had a separate Reentry Control System of sixteen thrusters located at the base of its nose, to provide rotational control during reentry. The Apollo Command Module had

1221-467: The system has dual and redundant circuits at all its stages. The total propellant load can vary between 440 kg (970 lb) and 892 kg (1,967 lb). Its main propulsion unit, uses the single S5.80 main engine ( SKD ). It is mounted on an electro mechanically actuated gimbal that enables it to rotate ±5° in pitch and yaw. It also has an electro mechanically actuated engine nozzle cover that takes 15 seconds to open and 25 seconds to close. All

1258-749: The two aft Orbital Maneuvering System pods. No nozzles interrupted the heat shield on the underside of the craft; instead, the nose RCS nozzles which control positive pitch were mounted on the side of the vehicle, and were canted downward. The downward-facing negative pitch thrusters were located in the OMS pods mounted in the tail/afterbody. The International Space Station uses electrically powered control moment gyroscopes (CMG) for primary attitude control, with RCS thruster systems as backup and augmentation systems. Unsymmetrical dimethylhydrazine Unsymmetrical dimethylhydrazine (abbreviated as UDMH ; also known as 1,1-dimethylhydrazine , heptyl or Geptil )

1295-471: The wingtips. The X-20 , which would have gone into orbit, continued this pattern. Unlike these, the Space Shuttle Orbiter had many more thrusters, which were required to control vehicle attitude in both orbital flight and during the early part of atmospheric entry, as well as carry out rendezvous and docking maneuvers in orbit. Shuttle thrusters were grouped in the nose of the vehicle and on each of

1332-414: Was achieved by firing pairs of eight 25-pound-force (110 N) thrusters located around the circumference of its adapter module at the extreme aft end. Lateral translation control was provided by four 100-pound-force (440 N) thrusters around the circumference at the forward end of the adaptor module (close to the spacecraft's center of mass). Two forward-pointing 85-pound-force (380 N) thrusters at

1369-419: Was no turbine start up and shut down hysteresis. For the new and improved high thrust RCS (DPO-B), known as the 11D428 , they kept the use of 14 thrusters, but instead of H 2 O 2 monopropellant they used the same cycle and propellant as the 11D426 SKD. They also increase the thrust from the previous 98 N (22 lbf) to 137.2 N (30.8 lbf). This enabled the DPO-B to act as backup engine for

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