Friday, March 10, 2017


Via Blue Origin's website, a promotional video of the upcoming New Glenn launch vehicle. Blue Origin describes it as a 7 meter diameter rocket with two or three stages, of which the first one will be powered by seven BE4-engines and which will also be reusable.

Of special interest are the BE4-engines, which may or may not end the US Space Program's dependency on Russian-made Energomash RD-180 engines. These have been powering Atlas launch vehicles since 2000. The BE-4 [Blue Engine 4 - MFBB] is a staged-combustion rocket engine of which the design envisages 2,400 kilonewtons (550,000 lbf) of thrust. First use in flight is expected from 2019 on, which would be two years earlier than the congressionally mandated cessation of the use of RD-180s.

Details are hard to come by, but the BE-4 would be using a dual propellant (liquid oxygen/liquid methane), and its cycle would be a single-shaft oxygen-rich staged combustion. Chamber pressure would be 13,400 kPa (1,950 psi).

The staged combustion cycle (aka topping cycle or pre-burner cycle), is a thermodynamic cycle rocket engines using a bipropellant. A part of one (kind of) propellant is burned in a pre-burner. Depending on which propellant is used for the preburner we talk of either oxidizer-rich staged combustion (ORSC), like in the BE-4, or fuel-rich staged combustion (FRSC). Either way, the resulting hot gases power the engine's turbines and pumps. The exhausted gases are then further injected into the main combustion chamber, together with the rest of the propellant, and combustion is completed. The main advantage of staged, or "closed" combustion is that all of the engine cycles' gases and heat go through the combustion chamber. The result is very high pressures in the latter, which does cause excessive wear.

Some more info via Scott Manley:

I'm no fan of Jeff Bezos the person but I have to hand it to him, he's doing an amazing job.


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