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Nitrogen tetroxide became the storable liquid propellant of choice from the late 1950's. Nitrogen tetroxide consists principally of the tetroxide in equilibrium with a small amount of nitrogen dioxide (NO2). The purified grade contains less than 0.1 per cent water. Nitrogen tetroxide (N2O4) has a characteristic reddish-brown colour in both liquid and gaseous phases. The solid tetroxide is colorless. N2O4 has an irritating, unpleasant acid-like odour. N2O4 is a very reactive, toxic oxidiser. It is non-flammable with air; however, it will inflame combustible materials. It is not sensitive to mechanical shock, heat, or detonation. Nitrogen dioxide is made by the catalytic oxidation of ammonia; steam is used as a diluent to reduce the combustion temperature. Most of the water is condensed out, and the gases are further cooled; the nitric oxide is oxidised to nitrogen dioxide, and the remainder of the water is removed as nitric acid. The gas is essentially pure nitrogen tetroxide, which is condensed in a brine-cooled liquefier. 1959 production amounted to 60,000 tonnes per year. In carload lots of one-ton cylinders, the price was $ 0.15 per kg. By 1990 NASA was paying $ 6.00 per kg due to environmental regulations.
Unsymmetrical Dimethylhydrazine ((CH3)2NNH2) became the storable liquid fuel of choice by the mid-1950's. Development of UDMH in the Soviet Union began in 1949. It is used in virtually all storable liquid rocket engines except for some orbital manoeuvring engines in the United States, where MMH has been preferred due to a slightly higher density and performance. Unsymmetrical dimethylhydrazine (UDMH) is 98 to 99 per cent pure and is described by Military Specification MIL-D-25604. The normally expected impurities are dimethylamine and water. UDMH is a clear, hygroscopic liquid which yellows on exposure to air. It absorbs oxygen and carbon dioxide. UDMH is a toxic volatile liquid. It exhibits the sharp ammoniacal or fishy odour which is characteristic of organic amines. It is completely miscible with water, ethanol, and most petroleum fuels. It is not shock sensitive. The vapours are flammable in air over 2.5 to 95 per cent concentration range. UDMH can be produced commercially by nitrosation of dimethylamine, to N-nitro-sodimethylrtmine, followed by reduction of the intermediate to UDMH and subsequent purification. UDMH can be prepared, also, by a modification of the Raschig process (see discussion of hydrazine), in which the chloramine intermediate is with dimethylamine rather than with ammonia. The price in 1959 for tank-car quantities was under $ 1.00 per kg. Engineering studies indicated a price of $ 1.00 per kg with large scale sustained production. But due to its toxic nature, production and transport costs soared in response to environmental regulations. By the 1980's NASA was paying $ 24.00 per kg.
Eng-engineslink | Thrust(vac)-kgf | Thrust(vac)-kN | Isp-sec | Isp (sea level)-sec | Designed for | Status | RDMT-0.4 X | 0 | 0.00 | 290 | Upper Stages | In Production | 11D431 | 1 | 0.01 | Upper Stages | In Production | RDMT-8 X | 1 | 0.01 | 296 | Upper Stages | Developed 1980's | Stepanov IS/US 1 kgf | 1 | 0.01 | Upper Stages | Out of Production | RDMT-12 | 1 | 0.01 | 279 | Upper Stages | In Production | 17D58E | 1 | 0.01 | 247 | Upper Stages | In Production | DST-25 | 3 | 0.03 | 285 | Upper Stages | In Production | RDMT-50 | 5 | 0.05 | 255 | Upper Stages | In Production | 11D446 | 5 | 0.05 | Upper Stages | In Production | 11D445 | 7 | 0.07 | Upper Stages | In Production | DST-100A | 10 | 0.10 | 304 | Upper Stages | In Production | DST-100 | 10 | 0.10 | 276 | Upper Stages | In Production | RDMT-100 | 10 | 0.10 | 260 | Upper Stages | In Production | Stepanov LK/LOK 10 kgf | 10 | 0.10 | Upper Stages | Out of Production | 11D428 | 11 | 0.11 | Upper Stages | In Production | RDMT-135 | 14 | 0.14 | 260 | Upper Stages | In Production | Stepanov IS/US 16 kgf | 16 | 0.16 | Upper Stages | Out of Production | RDMT-200 | 20 | 0.20 | 255 | Upper Stages | In Production | DST-200A | 20 | 0.20 | 300 | Upper Stages | In Production | DST-200 | 20 | 0.20 | 280 | Upper Stages | In Production | SE-5-2/-3 | 21 | 272 | Isayev TKS attitude | 40 | 0.39 | Upper Stages | In Production | Stepanov LK/LOK 40 kgf | 40 | 0.39 | Upper Stages | Out of Production | 11D458 | 40 | 0.39 | 252 | Upper Stages | In Production | RDMT-400A | 41 | 0.40 | 290 | Upper Stages | Developed 1980's | RDMT-400 X | 41 | 0.40 | 296 | Upper Stages | Developed 1980's | RDMT-400 | 41 | 0.40 | 255 | Upper Stages | In Production | DMT-600 | 61 | 0.60 | 301 | Upper Stages | In Production | 17D61 | 300 | 2.94 | 326 | Upper Stages | In Production | KDU-426 | 315 | 3.09 | 292 | Upper Stages | In Production | KRD-79 | 315 | 3.09 | Upper Stages | In Production | KTDU-417-B | 350 | 3.43 | 254 | Upper Stages | Out of Production | Isayev Polet/IS | 400 | 3.92 | Upper Stages | Out of Production | RD-0225 | 400 | 3.92 | 287 | Upper Stages | Hardware | KRD-442 | 447 | 4.38 | Upper Stages | In Production | RD-0237 | 500 | 4.90 | 200 | Upper Stages | Out of Production | RD-866 | 530 | 5.20 | 306 | Upper Stages | Out of Production | NII 612 kgf | 612 | 6.00 | 286 | Upper Stages | Developed | KTDU-80 | 632 | 6.19 | 302 | Upper Stages | In Production | RD-869 | 875 | 8.58 | 313 | Upper Stages | Out of Production | YF-23 | 1,124 | 11.00 | 282 | 260 | Upper Stages | In Production | RD-857 | 1,400 | 13.73 | 330 | Upper Stages | Out of Production | RD-0236 | 1,607 | 15.76 | 293 | 18 | Upper Stages | Out of Production | 11D416 | 1,670 | 16.40 | Upper Stages | Study 1968 | KRD-61 | 1,918 | 18.80 | 313 | Upper Stages | Out of Production | KTDU-425 | 1,922 | 18.85 | 312 | Upper Stages | Out of Production | KTDU-425A | 1,928 | 18.89 | 315 | Upper Stages | Out of Production | S5.92 | 2,000 | 19.60 | 327 | Upper Stages | Out of Production | S5.98M | 2,000 | 19.62 | 326 | Upper Stages | In Production | RD-859 | 2,045 | 20.05 | 312 | Upper Stages | Hardware | RD-858 | 2,050 | 20.10 | 315 | Upper Stages | Hardware | RD-864 | 2,060 | 20.20 | 309 | Upper Stages | Out of Production | RD-868 | 2,371 | 23.25 | 325 | Upper Stages | Developed 1983- | RD-0231 | 2,960 | 29.00 | 275 | First Stages | Out of Production | 11D430 | 3,000 | 29.43 | 307 | Upper Stages | In Production | RD-0214 | 3,150 | 30.98 | 293 | Upper Stages | In Production | RD-0207 | 3,150 | 30.90 | 297 | Upper Stages | Developed 1961-64 | S5.51 | 3,388 | 33.20 | 314 | Upper Stages | Hardware | 11D79 | 4,500 | 44.00 | Upper Stages | In Production | YF-40 | 5,000 | 49.00 | 295 | 260 | Upper Stages | In Production | RD-856 | 5,530 | 54.23 | 281 | Upper Stages | Out of Production | Izotov UR-100 stage 2 vernier | 6,000 | 58.00 | Upper Stages | Out of Production | Vexin A | 7,000 | 68.60 | 277 | 240 | Upper Stages | Out of Production | Vexin B | 7,687 | 75.40 | 251 | 221 | First Stages | Out of Production | RD-854 | 7,699 | 75.50 | 312 | Upper Stages | Out of Production | RD-861G | 7,796 | 76.45 | 325 | Upper Stages | Developed 1996- | RD-0221 | 7,954 | 78.00 | 330 | 300 | Upper Stages | Developed 1965-70 | RD-8 | 7,995 | 78.40 | 342 | Upper Stages | In Production | RD-861 | 8,026 | 78.71 | 317 | Upper Stages | In Production | Burlak Stage 2 | 10,000 | 98.00 | 330 | 230 | Upper Stages | Out of Production | Vexin C | 10,108 | 99.10 | 251 | 221 | First Stages | Out of Production | CZ-1C-3 | 11,000 | 107.90 | 287 | 258 | Upper Stages | Developed to 1984 | 8D725 | 12,000 | 117.00 | 325 | Upper Stages | Developed 1963-1970 | Topaze | 12,245 | 120.10 | 255 | 225 | Upper Stages | Out of Production | RD-0242 | 12,604 | 123.60 | 303 | First Stages | Developed 1977-83 | Izotov LK-700 | 13,400 | 131.00 | Upper Stages | Developed 1966-69 | 15D13 | 13,400 | 131.40 | Upper Stages | Study 1968 | 8D423 | 13,404 | 131.00 | 325 | Upper Stages | Out of Production | R6-117 | 13,500 | 132.00 | Upper Stages | Developed 1964-66 | 11D423 | 13,664 | 134.00 | 326 | Upper Stages | Developed 1963-67 | RD-862 | 14,544 | 142.63 | 331 | Upper Stages | Out of Production | RD-0245 | 21,516 | 211.00 | 300 | 280 | First Stages | Out of Production | RD-0217 | 22,330 | 219.00 | 313 | First Stages | Out of Production | RD-0216 | 22,330 | 219.00 | 313 | First Stages | Out of Production | 11D23 | 23,500 | 230.50 | Upper Stages | Study 1968 | RD-0235 | 24,473 | 240.00 | 320 | Upper Stages | In Production | 4D10 | 26,000 | 255.00 | Upper Stages | Out of Production | RD-863 | 28,230 | 276.84 | 301 | 259 | First Stages | Out of Production | RD-855 | 29,103 | 285.40 | 292 | 254 | First Stages | Out of Production | YF-3 | 29,980 | 294.00 | 287 | 260 | Upper Stages | In Production | Burlak Stage 1 | 36,500 | 360.00 | 320 | 270 | First Stages | Out of Production | RD-0234 | 53,000 | 520.00 | 310 | 285 | First Stages | Out of Production | RD-0233 | 53,000 | 520.00 | 310 | 285 | First Stages | Out of Production | RD-0204 | 57,000 | 559.00 | 311 | 278 | First Stages | Hardware | 8D43 | 57,000 | 559.00 | 316 | 284 | First Stages | Hardware | RD-0203 | 57,000 | 559.00 | 311 | 278 | First Stages | Hardware | RD-0206 | 59,350 | 575.50 | 326 | Upper Stages | Developed 1961-64 | RD-0210 | 59,360 | 582.10 | 327 | Upper Stages | In Production | RD-0211 | 59,360 | 582.10 | 327 | Upper Stages | Out of Production | RD-0213 | 59,360 | 582.10 | 327 | Upper Stages | In Production | RD-0205 | 62,500 | 606.40 | 322 | Upper Stages | Hardware | RD-0212 | 62,510 | 613.00 | 325 | Upper Stages | In Production | RD-0244 | 69,545 | 682.00 | 310 | 280 | First Stages | Out of Production | Viking 2 | 70,665 | 693.00 | 281 | 248 | First Stages | Out of Production | YF-22 | 73,200 | 717.80 | 295 | 260 | Upper Stages | In Production | Viking 2B | 73,419 | 720.00 | 278 | 248 | First Stages | In Production | Viking 4 | 73,518 | 721.00 | 296 | 200 | Upper Stages | In Production | YF-20A | 76,500 | 750.20 | 289 | 259 | First Stages | In Production | Viking 5C | 76,683 | 752.00 | 278 | 248 | First Stages | In Production | RD-0255 | 77,000 | 755.00 | Upper Stages | Out of Production | RD-0228 | 77,000 | 755.00 | Upper Stages | Out of Production | YF-22A/23A | 77,700 | 762.00 | 295 | 270 | Upper Stages | In Production | YF-22/23 | 77,700 | 762.00 | 295 | 270 | Upper Stages | Out of Production | YF-25 | 80,293 | 787.40 | 297 | 260 | Upper Stages | In Production | Viking 4B | 82,087 | 805.00 | 296 | 210 | Upper Stages | In Production | YF-20B | 83,238 | 816.30 | 289 | 259 | First Stages | In Production | RD-0243 | 84,200 | 825.80 | 300 | First Stages | Out of Production | YF-25/23 | 84,739 | 831.00 | 295 | 260 | Upper Stages | In Production | RD-250 | 89,840 | 881.00 | 301 | 269 | First Stages | Out of Production | RD-252 | 95,900 | 940.50 | 317 | Upper Stages | In Production | RD-262 | 96,000 | 941.00 | 318 | Upper Stages | In Production | RD-263 | 117,777 | 1,155.00 | 318 | 293 | First Stages | Out of Production | RD-268 | 126,000 | 1,236.00 | 319 | 296 | First Stages | Out of Production | RD-273 | 126,241 | 1,238.00 | 296 | First Stages | Developed 1975-82 | RD-253-11D48 | 166,725 | 1,635.00 | 316 | 285 | First Stages | In Production | 11D43 | 167,425 | 1,642.00 | 316 | 285 | First Stages | Developed 1960-64 | RD-254 | 175,000 | 1,716.00 | Upper Stages | Developed 1962-66 | RD-253-14D14 | 178,000 | 1,746.00 | 317 | 285 | First Stages | In Production | RD-275 | 178,000 | 1,745.00 | 317 | 285 | First Stages | In Production | RD-253-UR-700 | 178,000 | 1,745.00 | Upper Stages | Designed 1964-1968 | RD-253 | 178,000 | 1,745.00 | First Stages | In Production | Press Fed 200k | 206,803 | 2,028.00 | 306 | 200 | Upper Stages | Design concept 1960's | RD-0202 | 228,000 | 2,236.00 | 311 | 278 | First Stages | Developed 1961-64 | 8D43 + 11D43 | 229,200 | 2,247.45 | 310 | 280 | First Stages | Hardware | RD-0215 | 250,000 | 2,450.00 | 310 | 280 | First Stages | Developed 1962-65 | RD-251 | 270,000 | 2,643.00 | 301 | 269 | First Stages | In Production | RD-261 | 309,178 | 3,032.00 | 301 | 270 | First Stages | In Production | RD-264 | 461,000 | 4,521.00 | 318 | 293 | First Stages | Out of Production | RD-274 | 504,963 | 4,952.00 | 296 | First Stages | Developed 1975-85 | RD-270 | 685,000 | 6,713.00 | 322 | 301 | First Stages | Hardware | Press Fed 1000k | 998,639 | 9,793.20 | 300 | 240 | Upper Stages | Design concept 1960's | PF N204/UDMH-2165k | 2,165,100 | 21,232.00 | 267 | 245 | First Stages | Design concept 1960's | PF N204/UDMH-2912k | 2,911,600 | 28,552.00 | 267 | 245 | First Stages | Design concept 1960's | Press Fed 5748k | 5,748,000 | 56,368.00 | 267 | 245 | First Stages | Design concept 1960's |