Chemical
For chemical rocket engines to work it requires two parts an Oxidiser and a fuel.
Fuel is a substance that burns when combined with oxygen producing gas for propulsion. An oxidizer is an agent that releases oxygen for combination with a fuel. The ratio of oxidizer to fuel is called the mixture ratio. Propellants are classified according to their state - liquid, solid, or hybrid.
What is Rocket Fuel Anyway?
The gauge for rating the efficiency of rocket propellants is specific impulse, stated in seconds. Specific impulse indicates how many pounds (or kilograms) of thrust are obtained by the consumption of one pound (or kilogram) of propellant in one second. Specific impulse is characteristic of the type of propellant, however, its exact value will vary to some extent with the operating conditions and design of the rocket engine.
One advanced future chemical fuel is Metallic Hydrogen
ROCKET PROPELLANT PERFORMANCE
Combustion chamber pressure, Pc = 68 atm (1000 PSI) ... Nozzle exit pressure, Pe = 1 atm
Oxidizer
Liquid Oxygen
Liquid Fluorine
FLOX-70
Nitrogen Tetroxide
Red-Fuming Nitric Acid
(14% N2O4)
Hydrogen Peroxide
(85% concentration)
Nitrous Oxide
Chlorine Pentafluoride
Ammonium Perchlorate
(solid)
Fuel
Liquid Hydrogen
Liquid Methane
Ethanol + 25% water
Kerosene
Hydrazine
MMH
UDMH
50-50
Liquid Hydrogen
Hydrazine
Kerosene
Kerosene
Hydrazine
MMH
UDMH
50-50
Kerosene
Hydrazine
MMH
UDMH
50-50
Kerosene
Hydrazine
HTPB (solid)
Hydrazine
Aluminum + HTPB (a)
Aluminum + PBAN (b)
Hypergolic
No
No
No
No
No
No
No
No
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
Yes
No
Yes
No
No
Mixture Ratio
5.00
2.77
1.29
2.29
0.74
1.15
1.38
1.06
6.00
1.82
3.80
3.53
1.08
1.73
2.10
1.59
4.42
1.28
2.13
2.60
1.94
7.84
2.15
6.48
2.12
2.12
2.33
Specific Impulse
(s, sea level)
381
299
269
289
303
300
297
300
400
338
320
267
286
280
277
280
256
276
269
266
270
258
269
248
297
277
277
Density Impulse
(kg-s/l, S.L.)
124
235
264
294
321
298
286
300
155
432
385
330
342
325
316
326
335
341
328
321
329
324
328
290
439
474
476
Chemical Rockets in progress
Russian RD-191
Proposed for the Angara (rocket family)
Sea Level: Thrust 196 tons SPI 309s
Vacuum: Thrust 212 tons SPI 337s
First test flight slated for June 27, 2014.
American
The Raptor Engine proposed for the Falcon Super Heavy rocket (Starship).
Sea Level: Thrust *** tons SPI ***s
Vacuum: Thrust 310 tons SPI 382s
SpaceX methane-fuelled Raptor rocket engine parts to be tested at NASA's Stennis on the E-2 Test Stand around June 2014 . (see Stennis Space Center )
Due to the the large thrust of a full Raptor engine SpaceX will need to construct a new engine test stand, early 2015.
Final Engine may not be to version 5 according to Elon Musk in Sept 2021.
The Raptor Engine proposed for the Starship version 1.0
250Bar
Vacuum engines: Exit diameter 2.4m, Thrust 1,900 kN, Isp 375 s
Sea level engines: Exit diameter 1.3m, Thrust (SL) 1,700 kN, Isp (SL) 330s, Isp (Vac) 356s
Blue Origin
BE-3 Liquid Hydrogen Rocket Engine
50 Tons
BE4 Liquefied Natural Gas (LNG) /methane powered Engine
Aerojet Rocketdyne
AR1 is a proposed 2,200-kilonewton-class (500,000 lbf) thrust kerosene/LOX rocket engine slated for 2019
ARCA Space Corporation
linear aerospike engine
Demonstrator 3 rocket designed to power a single-stage to orbit (SSTO) satellite launcher.
China
"Engineers are researching and developing a 500-ton-thrust liquid oxygen/kerosene engine and a 200-ton-thrust liquid oxygen/liquid hydrogen engine"
going to be used for China's upcoming new Long March 9 Heavy lift Rocket.
No firm date yet but maybe 2025.
Fuels
RP1 (rocket propellant 1) - MIL-P-25576 Rev. C ROCKET GRADE KEROSENE
LH2 - liquid hydrogen
Nitrogen tetroxide (N2O4) and hydrazine (N2H4), MMH, or UDMH.
3D-printed fuel (Developmental)