Given the recent European Space Agency S-ELSO study indicating that Skylon is 'financially feasible', the Engineer magazine polled its readership on what the next course of action should be. A plurality of respondents (35%) thought that Skylon should be fully funded by ESA as its next launcher system.
The latest version of the Skylon Users' Guide (v2.1) has been published by Reaction Engines. Version 2 was extensively revised in light of the development of the D1 vehicle configuration, and the ESA S-ELSO study into the economics of a Skylon-based launch system.
Reaction Engines Ltd announces the completion of the most detailed study to date on the SKYLON vehicle’s systems and infrastructure
The SKYLON-based European Launch Service Operator (S-ELSO) study has been carried out in response to the European Space Agency’s ‘New European Launch Service’ requirements for lowering the cost of European launch services in the 2020 – 2040 timeframe. The study was led by Reaction Engines with support from Airbus Defence and Space, Grafton Technology, London Economics, Jacobs, QinetiQ Space, and Thales Alenia Space.
SKYLON is a reusable launch vehicle designed to be powered by the SABRE rocket engine, a new class of engine that offers significantly improved performance compared to conventional rocket technology. The €1M ESA-funded study has identified and evaluated SKYLON’s key systems and infrastructure to prove that all current mission requirements for ESA launches can be fulfilled, whilst reducing the cost and increasing reliability over existing expendable launch vehicle technology. The study came to a number of conclusions:
- SKYLON vehicles operated from Europe’s launch site in French Guiana, together with a reusable upper stage, can meet all Europe’s launch operator requirements.
- SKYLON is potentially Europe’s most cost effective space access solution, and is able to compete with existing and anticipated competition.
- The SKYLON system, benefitting from its reusable design, has the potential to significantly undercut the price performance of the world’s most competitive current launch systems.
- Once operational, SKYLON and its infrastructure can be operated independently of public subsidy, allowing economic exploitation of the launch vehicle.
- A wide range of payloads can be supported within SKYLON’s 15 tonne to LEO payload
capability. This includes mini, micro, and nano -scale satellites, either individually or in
constellations, and reusable upper stages to allow higher orbits to be reached.
- SKYLON offers additional capabilities that previous European launchers cannot, e.g.
spacecraft return, in-orbit servicing and human passengers.
BBC Science correspondent, Jonathan Amos, reports on the findings of a study of the economic feasibility of SKYLON (a conceptual reusable single-stage-to-orbit spaceplane) and a SKYLON–based European Launch Service Operator (S-ELSO), validated by the London Economics Aerospace team.
“It appears a feasible proposition, economically. That is the conclusion of a study that considered a European launch service based on a Skylon re-usable spaceplane. The report, commissioned by the European Space Agency (Esa), was led by Reaction Engines Limited (REL) of Oxfordshire with help from a range of other contractors such as London Economics, QinetiQ and Thales Alenia Space (TAS).”
Lecture given by Alan Bond, Managing Director of Reaction Engines at Merton College, Oxford. posted in March 2014.
A few highlights:
* To date, the engine pre cooler test programme has included 600 tests, 300 in cryogenic pre cooler mode. Precooler has run at -150C, -120C in steady state. Demonstrated stable flow, transitional between turbulent and laminar flow. Verified thermomechanical and aerodynamic integrity, fulfilled technical objectives of ESA programme.
* The STILETTO staged combustion engine tested by Airborne Engineering and intended for the A2 hypersonic airliner, demonstrated a reduction in NOx levels below detectability. Functions by accelerating the flow while combustion is taking place, such that the static temperature of the flow never exceeds 2000K (some combustion pressure is lost as a result). Estimated range of A2 vehicle 21,000km at Mach 5, 23,000km subsonic.
* The latest iteration of the SABRE engine, SABRE 4, halves fuel consumption in air breathing mode. Self-ferrying of a vehicle from the UK to an equatorial launch site is possible. SABRE 4 may provide sufficient margin to install high-lift devices to shorten takeoff run.
* REL currently employs over 60 people.
* REL studying reactivation of Westcott K-site (formerly used for testing Polaris missile motors), to test rocket engines of up to 120 tons thrust.
* Phase 3 ramp up has started already (shown as Jan-Apr 2014), expected to last 3.5yr to Oct 2018.
* Vehicle cost ~£1bn. REL sees a global market for ~30 vehicles. Mission cost £5-10M. Mission lead time ~days. 1/20,000 failure rate (LOV) at entry into service, improving to 1/10^6 over time. Various mission abort scenarios discussed.
* AFRL interest is in “verifying engine cycles to see if they work”. Avio and ESA have already checked this. Reply by end of May?
* REL in dialogue with aerospace firms around the world. AB envisions distinct Euro and US efforts, driven by ITAR. US vehicle would have US engines built by US-based REL-subsidiary, in US airframe.
* AB expects competition from other (presumably airbreathing) projects, sparked by Osborne funding announcement.
Rocketeer comments: The cartoon accompanying the Economist article is just inspired ;-)
The comments by Dumbacher (NASA) and Bonnal (CNES) in the SpaceNews article illustrate just how much the incumbent launch providers are whistling past the graveyard in the face of SpaceX reusability developments. Dumbacher claims that the viability of reusability depends on market demand, ignoring that the Falcon-9 can function in either reusable or expendable mode, and is already capturing the market at its unprecedentedly low expendable price. If the market is small, SpaceX wins. If the market is big, SpaceX wins more.
Dumbacher also makes an unconvincing comparison between SSME and the Merlin-1D engine. A highly-complex, high chamber-pressure staged-combustion LOX/LH2 engine operating beyond its rated power is NOT THE SAME as a simple, low chamber-pressure robustly engineered gas-generator LOX/kero engine designed for serviceability and minimum parts count. Apples, meet oranges.
Bonnal's argument distils to "we couldn't do it, therefore no-one can". He says: "Safety factors have to be higher, and you need around 30 percent more propellant in the first stage to fly the stage back to the launch site.” Yes, and SpaceX have already factored that into the quoted performance numbers for the F9v1.1.
£250M Phase 3 programme will demonstrate SABRE engine technologies in a system complex, and take the SABRE engine design to CDR. Technology development projects on Skylon structure and TPS also undertaken. Latest iteration of the engine, the SABRE 4, improves the efficiency of the air breathing phase, but requires some new technologies which are currently being developed. That work is expected to be completed in mid-2014, when the final decision between SABRE 3 and SABRE 4 will be taken.
* STRIDENT cold flow tests to explore nozzle flow at sea level conditions. Hot-fire test engine STOIC under development
* SABRE nacelle intake model has been tested in hypersonic gun tunnel by Gas Dynamics Ltd
Preliminary Phase 3 activities started in spring 2013, solely funded by Reaction Engines, leading into an 8 million euro Phase 3A in autumn 2013. This phase will last around 18 months, and is 50:50 funded by REL and the UK subscription to the European Space Agency.
Phase 3a activities include:
* SABRE 4 design to take it to System Requirements Review
* Preliminary design of ground demonstration engine (Sceptre)
* Pre-cooler tube cost reduction
* Further work on HX4 heat exchanger micro channel manufacture
* Further work on HX3 high-temperature heat exchanger technologies
* Further work on chamber technology
* Further work on altitude compensation nozzles
* Investigation of the intake in subsonic conditions
* Further work on the intake in supersonic conditions
* SKYLON vehicle configuration studies
Phase 3a will overlap with the main Phase 3, which has an intended budget of £240M — primarily devoted to the detailed design of the SABRE Block 1 engine, and the construction of the Sceptre ground demonstrator engine.