ESA, ArianeGroup sign prototype contract for Prometheus low-cost (OK, reusable too) rocket engineby Peter B. de Selding Dec 14, 2017PARIS — The European Space Agency on Dec. 14 contracted with ArianeGroup to design, build and tests two prototypes of the reusable, LOX-methane Prometheus rocket engine, with test-bed firings to occur from 2020
14 December 2017An ultra-low cost reusable rocket engine, Prometheus, using liquid oxygen–methane propellants, is set to power Europe’s future launchers.Today, ESA and ArianeGroup signed a contract to develop a full-scale demonstrator to be ground tested in November 2020.Prometheus demonstrates the systematic application of an extreme design-to-cost approach, new propellant and innovative manufacturing technologies. It lowers costs to a tenth of those for Ariane 5’s Vulcain 2 engine. Additive layer-by-layer manufacturing of engine parts enables faster production, with fewer parts.Key characteristics of Prometheus include a computer system enabling realtime adjustment and immediate diagnosis for potential reusability.Methane propellant is widely available and brings high efficiency, standardisation and operational simplicity, making it a perfect candidate for a reusable booster engine demonstration. By 2020, technical knowledge of liquid oxygen–methane propulsion gained through the Prometheus project will allow fast and informed decisions to be made on useful applications.Prometheus provides a nominal 1 MN of variable thrust, is suitable for first- and second-stage applications, and is reignitable. It will propel a range of next-generation launchers, including future evolutions of Ariane 6. The Prometheus contract, worth €75 million, was signed by ESA Director of Space Transportation, Daniel Neuenschwander, and Alain Charmeau, CEO at ArianeGroup, at ESA headquarters in Paris in the presence of ESA Director General Jan Wörner.The project is part of ESA’s Future Launchers Preparatory Programme.“Prometheus will power Europe's future launchers, forging a path of continuous improvement in competitiveness,” commented Mr Neuenschwander.“This contract paves the way for the future of Europe’s space transportation, and the development of European propulsion technology of tomorrow,” added Mr Charmeau. The project benefits from significant synergies with other launcher demonstration projects within ESA, national agencies and industry.
The implied devastating message seems to be : the SpaceX approach was the right one, despite every statement by European big wigs since 2002.
Quote from: hektor on 12/26/2017 08:32 amThe implied devastating message seems to be : the SpaceX approach was the right one, despite every statement by European big wigs since 2002.Nothing devastating about that implied message. The big wigs have been wrong numerous times, not just on this one.
3) The vehicles are modeled with Al 2219 alloy, not AL-Li alloy which is state-of-art. They also model aluminum isogrid interstages, whereas carbon fiber over Al honeycomb is SOA. The stage mass fractions are not quite as good as F9.
A technical question related to the Prometheus engine:What happens with the chamber pressure of a rocket engine when the propallent mass-flow is doubled?I know Ft=m.*ISP*g0. (Thrust = propellant mass flow * ISP * gravitational asseleation.) (ISP in s not m/s, USA equation.) So to double thrust, the mass flow has to be doubled. ISP increase (slightly) with higher pressure. But does the chamber pressure double when mass flow is doubled in the same combustion chamber (engine bell)?It's reported that Prometheus will be a LOxLNG GG engine with 1000kN vacuum thrust. I guess ISP will be about 340s (3335m/s), this equates to a propallent mass flow of ~300kg/s.
https://www.eucass.eu/doi/EUCASS2017-537.pdfFrom the above document, it appears Prometheus is Europe's answer to the Merlin engine. It uses the same gas generator cycle for lower development costs, belongs to a similar thrust class as Merlin 1D. Significant parts of it will be 3D printed and it's intended to be used as a single engine or in clusters depending on launch vehicle. The biggest differences are the use of a more efficient, reuse friendly fuel Methane and the larger throttle range of Prometheus (30 -110%). Totally pie in the sky speculating here, but Europe could end up creating a launch vehicle similar to Falcon 9 but even better optimized for reuse. Think of a VTVL booster the width of Ariane 6, lifted by a cluster of 7-9 Prometheus engines and a similar upperstage using a single vaccum optimized version Or for higher performance missions, a derivative of the Hydrolox Vinci-Upper Stage on Ariane 6. The position of Korou should be a relative advantage for a reusable booster on GTO missions and landing stages on an ocean platform should be possible for the most challenging trajectories. As things stand, it's hard to see a dramatic change from the incumbent program happening soon without external events pressuring European politicians to back expediting Ariane Next. A shock event like Ariane Group suddenly losing a lot of the launch business abruptly might lend some urgency to Callisto/Prometheus.
France, Germany studying reusability with a subscale flyback boosterby Caleb Henry — January 8, 2018
New article on Callisto:QuoteFrance, Germany studying reusability with a subscale flyback boosterby Caleb Henry — January 8, 2018http://spacenews.com/france-germany-studying-reusability-with-a-subscale-flyback-booster/Some interesting quotes from Marc Astorg, head of CNES’s Launch Vehicles Directorate, and Hansjörg Dittus, executive board member for space research and technology at DLR. Eg re whether they're copying SpaceX (in part responding but not copyuing) and too many years behind (claim advantages to going after SpaceX).