Le projet SKYLON

[Geb]

Bonjour,

Je savais ce qu’est la poussée vectorielle. Je voulais dire que je ne savais pas que le Skylon en était équipé, ce qui paraitrait paradoxal puisque, comme le montre très bien le site en question, ce système est utilisé sur les chasseurs pour leur donner de l’agilité, ce dont le Skylon ne doit pas avoir besoin. De plus, vu l’emplacement des moteurs, cela ne doit pas être très efficace.

Je ne sais pas si on peut qualifier celles-ci de tuyères orientables (et donc de poussée vectorielle) mais d’après le rapport de l’ESA de mai 2011, les deux tuyères de chacune des nacelles du Skylon peuvent changer leur position à la fois en lacet et en tangage de + ou – 3 degrés.

[...] The engines are mounted in cambered axisymmetric nacelles in the wingtips. Control of the vehicle while in the atmosphere is achieved by foreplanes in pitch, ailerons in roll, and an aft mounted all moving fin in yaw. The rocket engine exhaust nozzles are gimballed individually but move together within each nacelle and are designed for ±3 deg movement in pitch and yaw. The nozzles are ‘frozen’ during the air breathing ascent but become ‘live’ during the rocket ascent. During the rocket ascent main engine gimballing takes over progressively from the aero controls as the dynamic pressure reduces, until finally reaction control thrusters take over at main engine cut-off. [...]

Cordialement
-----

[Saint-Sandouz]

Le fait est que c’est logique : il faut bien un moyen d’orientation dans le vide.

ND

[Geb]

Le fait est que c’est logique : il faut bien un moyen d’orientation dans le vide.

Les tuyères du SABRE sont légèrement orientables donc (au-delà de 26 km d'altitude). Ensuite, les 38 petits propulseurs (sans doute à l'hydrazine) se chargent de contrôler les mouvements du Skylon une fois en orbite.

Je me permet de recopier ici un passage d'un article intéressant de The Register à propos de la conférence donnée par Roger Longstaff le mardi 12 avril 2011 à San Francisco (Californie) :

[...] the company is expecting to test a SABRE on the ground as soon as 2013 or 2014. However, before REL's backers will fund the building of a complete SABRE, it seems that they need to see the pre-cooler working. It is this which will be trialled in June.

"[The pre-cooler] is the only brand-new piece of technology," Longstaff told InnovationNewsDaily.com last week.

Varvill had previously said that REL has a 10-year roadmap to actual Skylon flights, with costs during that time of maybe $15bn. The plan works like a snowball: at first, comparatively small investments lead to comparatively minor tests and trials, which then unlock bigger sums allowing bigger building blocks to be built and validated and so on – until in the final years, big cheques get signed and actual Skylons get built. [...]

Un business plan sur le modèle de l'effet boule de neige donc.

Cordialement

[Moinsdewatt]

....
Un business plan sur le modèle de l'effet boule de neige donc.

....

C' est le méme baratin que pour toutes les start up.

[Geb]

Bonsoir,

C' est le méme baratin que pour toutes les start up.

Loin de mériter le qualificatif de "baratin", je dirais plutôt que c'est surtout la meilleure façon de procédé.

Le matériau du precooler a été défini sur appel d'offre (il fallait des tubes résistants à la chaleur et à l'oxydation) par la compagnie Fine Tubes Ltd en 1999.

Je suis enfin parvenu à retrouver l'article dans lequel j'avais pu lire cette information :

Newsletter of the Heat Exchanger Action Group (février 2004)

[...] Fine Tubes Ltd successfully manufactured the first tubing to REL’s specification in 1999. The concept and detail of our core technologies is very innovative but they all use current manufacturing methods, existing technologies and known materials.

Following private investment in March 2001, an experimental demonstration of REL’s frost control technologies was undertaken. The program has already been very successful and has almost been completed. The current program, funded until March 2003, has been directed at resolving those areas of perceived difficulty relating to lightweight compact heat exchangers operating in a frosting environment and will demonstrate all the following:

• Liquid condensate management across the relevant temperature range.
• Manufacturing technology of heat exchangers with small diameter tubes made from Inconel 718.
• Low temperature heat exchanger operation in flowing conditions.
• High temperature, high stress creep resistance in furnace conditions.
• Confirm heat transfer and pressure loss predictions
• Confirm weight predictions for the heat exchanger and frost management system.

On December 2001 REL was awarded a SMART (Feasibility) Award by the Department of Trade and Industry to investigate the manufacturing processes involved in building pre-coolers, This programme is progressing well and is due to be completed in January 2003.

Voilà... pour les historiens et autres passionnés de dates (comme moi )

Cordialement

[Geb]

Je suis enfin parvenu à retrouver l'article dans lequel j'avais pu lire cette information

Je viens de trouver un article récent (3 juin 2011) qui cite un deuxième fournisseur, High Tech Tubes, pour les tubes en Inconel 718 nécessaires à Reaction Engines Ltd (pour rappel : 0,98 mm de diamètre, paroi de 40 µm d'épaisseur).

Sources : Hybrid engine devlopments on track

Morceau choisi...

Putting theory to the test, a Technology Demonstration Programme (TDP), which was initiated in February 2009 and is about to produce formal results, includes the construction and test of a scale version of the SABRE pre-cooler. Also being put to the test are the manufacturing capabilities of several specialist companies, and of course the supply chain.

The tubes for example are being manufactured by Fine Tubes in Plymouth and High Tech Tubes in County Kerry, Ireland, using tube-drawing techniques; as used to make needles for example. Whilst the process dates back to the early days of the Industrial Revolution, today’s manufacturing techniques are being pushed to the limit because of the combination of small diameter (OD, 1mm), small wall thickness (typically 40 microns) and material used (Inconel 718).

Post-manufacture the tubes are delivered to Reaction Engines’ facility in Abingdon, where they are subjected to a series of dimensional and strength tests. Defect-free tubes are then loaded into a braze fixture built by Brite Precision and Crossman Engineering. Both companies had previously been suppliers to Reaction Engines, but were acquired by the company in 2009. The company has also invested heavily in new machinery, including a Sodick wire-eroding machine, a Hurco 5-axis milling machine and two new CNC lathes.

The final manufacturing stage sees the entire fixture loaded into a furnace where it undergoes an intensive time/temperature brazing cycle. It is then subjected to leak and pressure tests.
The scaled pre-cooler for the TDP is being built from 21 full-size modules, compared to the 80 or so that SABRE will use. The definitive test will be the pre-cooler’s ability to dissipate heat, and for this Reaction Engines has built a test bed at the Culham Science Centre, where the company has its HQ. The test bed incorporates a Viper 532 jet engine and a helium coolant system that will enable the pre-cooler to operate at temperatures as low as -150ºC.

Cordialement

[Geb]

La participation de High Tech Tubes en tant que fournisseur est de fait exprimé dans les nouvelles de Reaction Engines de juin 2009 :

[...] The first batch of pre-production tubes for the heat exchangers from High Tech Tubes has now been delivered. The tubes are currently undergoing trials. [...]

Cordialement

[Geb]

Il est donc faux de dire que BAE et Rolls Royce "comptent" dans le secteur du spatial en Europe.

À ceci près que Rolls-Royce et BAe ont pris en charge le développement du HOTOL de 1984 à 1988.

Rien que du point de vue moteur, le SABRE fonctionnant dans deux modes distincts (aérobie et fusée), il nécessiterait vraisemblablement une expertise du secteur aéronautique, au moins pour l’entrée d’air et le statoréacteur, aussi bien que du secteur astronautique.

D’ailleurs c’est Rolls-Royce qui avait développé le moteur du temps de HOTOL, alors que cette compagnie avait dû mettre au rencards ses activités astronautiques dès 1972 (avec l'abandon du programme Black Arrow).

J'ajoute que le Skylon en lui-même ressemble plus à un avion qu'à une fusée, et que la partie aérobie du vol doit durer 694 secondes contre 285 secondes pour la partie fusée.

Pour ce qui est de la nouveauté, les échangeurs, c’est REL qui s’en chargerait avec les sous-traitants actuels sans doute (soit Fine Tubes, High Tech Tubes, Brite Precision, Crossman Engineering et Tenmat pour le REFEL du HX3).

Cordialement

[Moinsdewatt]

À ceci près que Rolls-Royce et BAe ont pris en charge le développement du HOTOL de 1984 à 1988.....

C 'est donc bien du passé, comme je le disais.

[Geb]

Bonsoir,

Outre les 5 compagnies susmentionnées :

- Fine Tubes,
- High Tech Tubes,
- Brite Precision,
- Crossman Engineering,
- Tenmat.

Ce pdf mentionne également dans le développement des échangeurs les compagnies Poeton Industries et Alan Spargo ainsi que le support technique de la United Kingdom Atomic Energy Authority (UKAEA).

Hors si on se replonge dans la biographie succincte de Mr Alan Bond, exposée ici, on peut lire ceci :

In 1976 Alan joined the Atomic Energy Authority (AEA) in Culham to work on nuclear fusion.

J'ai donc fait une recherche sur le Culham Centre for Fusion Energy (CCFE) ou notre ingénieur favori à travailler à partir de 1976 et j'ai fait d'autres découvertes intéressantes d'un point de vue historique.

Premièrement, le Culham Innovation Centre où sont situées à la fois le CCFE et Reaction Engines Ltd, a fêté ses 10 ans le 21 février 2011 :

Culham Innovation Centre marks 10 Years of innovation Success

Currently, there are 15 innovative companies located at the Centre and a further seven firms using the virtual office service. They include:

Reaction Engines, a developer of advanced aerospace engines incorporating compact and lightweight heat exchanger technology that can be used to accelerate aircraft to Mach 5. Using these engines the company is developing an unmanned spaceplane, Skylon, which would take off from a runway, fly into space and return to land on the same runway. It could be used to deploy telecommunications satellites into orbit and would have an operational life of 200 flights. A full version of the heat exchanger is due to be demonstrated on an experimental rig at Culham this summer. Reaction Engines now has 45 employees and has manufacturing facilities in Newbury, Wantage and Abingdon as well as test facilities at Westcott in Buckinghamshire.

[...]

Alan Bond, managing director of Reaction Engines, said: 'At Culham Innovation Centre we can develop our business according to our aspirations and needs. We have expanded to larger premises in the Centre with no hassle and we have benefited greatly from being located on a world class science and technology campus, in particular by taking advantage of the technical support package offered by the UK Atomic Energy Authority, and from the opportunity to learn from the knowledge and experiences of businesses facing similar challenges. We hope to be part of a very successful future for the Innovation Centre.'

L'UKAEA est apparemment très fier du passage du jeune Alan Bond (il avait 32 ans en 1976) dans ses installations et le cite même en exemple dans ses brochures :

[...] Alan Bond continues to work part-time on the UKAEA Fusion programme, and has based his business at the Culham Innovation Centre. “Through the UKAEA’s Technical Support package we’ve been able to draw on bonding and jointing expertise that is unique to fusion to expedite development of our heat exchanger technology.”

L'histoire de Reaction Engines Limited au début des années 2000 est souvent liée à celle du UKAEA à travers l'obtention d'au moins 2 (en 2002 et 2004 à ma connaissance) Department of Trade & Industry (DTI) SMART (Small firms Merit Award for Research & Technology) Award. Alan Bond est ainsi apparu un bon nombre de fois dans la newsletter du Science Centre de Culham :

En août 2001 :

Mr Bond says: “We’re currently working on an engine for a space plane that operates at speeds of Mach 6. Until now jet engines have struggled to reach Mach 3 speeds because of the high temperature of the intake air. Our technology allows us to cool this down so it can be used in the engine’s subsonic combustion cycle. We were attracted by UKAEA’s skills in brazing and materials testing, together with a ‘can do’ approach to overcoming problems that is invaluable to any company pushing back the boundaries of engine technology.”"]Mr Bond says: “We’re currently working on an engine for a space plane that operates at speeds of Mach 6. Until now jet engines have struggled to reach Mach 3 speeds because of the high temperature of the intake air. Our technology allows us to cool this down so it can be used in the engine’s subsonic combustion cycle. We were attracted by UKAEA’s skills in brazing and materials testing, together with a ‘can do’ approach to overcoming problems that is invaluable to any company pushing back the boundaries of engine technology.”

En février 2002 :

The SMART award feasibility study funding will lead to production of a fully functioning heat exchange module based on the high nickel alloy Inconel 718. Managing Director Alan Bond says: “The successful peer review of our award application gives a tremendous boost to our credibility when competing for future venture capital funding.”

Over the next nine months Reaction Engines engineers will be working closely with the Special Techniques Group at Culham to complete the development, drawing on the consultancy services
available as part of UKAEA’s Technical Support Package.

En août 2004 :

Reaction Engines – using TSP to develop compact heat technology

Another early user of the TSP was heat exchanger innovator, Reaction Engines Ltd. The company specialises in developing compact heat exchanger technology that will eventually be used in space planes and high speed commercial airliners.

In addition to high speed cameras and assistance in setting up a wind tunnel, the TSP has provided Reaction Engines with access to precision engineering expertise used in completing a SMART award. Recently the company was given a second SMART award worth £142,000 to build a heat exchanger prototype production unit. The unit will undergo trials in a test facility being built on the Culham site using a Viper gas turbine jet engine early in 2005. “The TSP has been very useful, it is convenient and allows doorstep access to the expertise of UKAEA’s Special Techniques Group with minimum bureaucracy,” says Managing Director Alan Bond.

Sur le même site web, à l'occasion du prix délivrer par l'ESA le 19 février 2009 :

http://www.fusion-industry.org.uk/te...ionengines.htm

[...] The key technical challenge for REL is to take the pre-cooler from the laboratory to the industrial scale for testing on the company's Viper B9 engine test facility at Culham. It will produce 26 heat exchange modules over the next 12 months.

“Over the years the CCFE's Technical Support Package has allowed us to build up considerable expertise within REL on brazing and tube manipulation techniques. It is still an important part of our development work. Recently we've used it to assist us with wind tunnel diagnostics data acquisition and, all being well, it will enable us to overcome any technical problems we may encounter as we scale up and test the pre-cooler during the course of the demonstration programme,” said Alan Bond.

En janvier 2007 :

[...] “Our objective is to cool hot gas from 1,000 ºC to - 100 ºC in the pre-cooler prior to compression. By understanding the flow of hot gas through the pre-cooler matrix we are able to adjust the matrix pattern and maximise heat transfer from gas to coolant,” said Reaction Engines Propulsion Engineer Helen Webber.

In its latest use of UKAEA’s TSP, to visualise the flow path of gas through the tube matrix, Reaction Engines has used a high-speed camera operating at 1,800 frames per second which is normally deployed by UKAEA fusion scientists on MAST to record the formation of plasma during fusion. The camera images have allowed Reaction Engines to capture the cross counter flow across the matrix and identify any problem areas.

Bonne lecture.

[Geb]

C 'est donc bien du passé, comme je le disais.

Comme j'essayais de l'exprimer auparavant, le Skylon comme le HOTOL avant lui, n'est pas, paradoxalement, un programme de développement purement "spatial" à proprement parler.

Donc, des compagnies européennes, outre BAe Systems et Rolls-Royce, comme EADS (REL s'est exprimé une fois en faveur d'une implication d'Airbus) mais aussi Finmeccanica (Italie), ou encore Safran, Thales et Dassault Aviation du côté français pourraient être intéressées.

À cause de ITAR, Reaction Engines a bien exprimé le fait que toute implication d'une entreprise américaine serait rendue trop longue et/ou coûteuse. Les poids lourds comme Boeing, Lockheed Martin, Northrop Grumman, General Dynamics et Raytheon semblent donc définitivement écartés d'un éventuel programme de développement du Skylon.

Cordialement

[Geb]

Bonjour,

Un lien vers un memorandum soumis par Reaction Engines Limited au comité pour le commerce et l'industrie de la chambre des communes du parlement britannique, le 28 février 2000.

C'est le compte-rendu le plus complet que j'ai pu lire sur la situation difficile dans laquelle se trouvait la compagnie REL à la fin des années 1990.

When the BNSC was formed under the Directorship of Roy Gibson in 1986 it was mandated to administer all aspects of the UK's space interests, including the enabling technologies. Following the policy under Prime Minister Thatcher and the then Minister for Space Kenneth Clarke all Government support for work on launchers, particularly HOTOL, was terminated. Gibson was forced to resign having encouraged work in some areas without the funding being authorised and was soon replaced by Arthur Prior as the permanent DG of the BNSC under Clarke as Minister.

Prior had clearly been given the mandate to ensure that no support would be given to transportation development despite the success of the HOTOL project. Clarke had taken reference from the space science community at the Appleton-Rutherford Laboratory in reaching this directive and Thatcher was unable to overcome what has been termed "the Concorde Factor", despite the fact that the market situation into which HOTOL was being designed had no similarities whatever with that of Concorde. Indeed apart from both flying and each having a pointed nose there were no similarities whatever between the two projects. This much of the background is known from the close liaison in existence between Government departments and the central figures of the HOTOL project in the late 1980s.

However, despite subsequent change of ministers and DGs and senior officers of the BNSC, the intransigent policy remained. During the early 1990s, the ESA began a technology investigations program called FESTIP [Future European Space Transportation Investigations Programme]. This program had actually been pressed for by the British during the HOTOL program, and its origins were freely acknowledged within the ESA FESTIP management team. Within the UK discussions were held between industry and the BNSC to plan UK participation. A considerable amount of preparatory work was carried out by UK industry to support the proposal for entry to the program. However this did not occur.

In the course of a heated exchange over this failure between the then DG Derek Davis and REL, it emerged that the BNSC had "insufficient funds to join the program". When pressed Davis admitted that he had not re-approached the minister for increased funding since it was not regarded as of sufficient priority.

In September 1995 the then Minister Ian Taylor took the initiative to revise the UK Space Policy through a public meeting at the University of Surrey. Despite the fact that this was supposed to be a review of policy, transport infrastructure was not even an agenda item and a great deal of debate came from the floor on this issue.

In April 1996, motivated by the Surrey debate, UK industry formed a working group (called the Launcher Services Advisory Board or LSAB) from all of the space companies with launcher interests. This body held several meetings and involved the BNSC.

Despite this extraordinary move by industry to demonstrate its solidarity in wanting to participate in launcher activity and also demonstrating the range of expertise which it could still muster, there was no inclusion of its interests in the final Space Policy document presented at QMW in June 1996. Loud criticism from the floor at that meeting brought no redress.

The LSABs eventually was absorbed into the United Kingdom Industrial Space Committee (UKISC) as the launcher sub-committee (LSC). At the BNSC public meeting in Leeds in April 1998, launchers were again not an agenda item despite continuously expressed interest by industry in UK participation in this activity. The issue was raised with the Minister, John Battle, before he left the meeting for another engagement. Battle gave instructions to the BNSC that launchers were to be considered in a separate meeting. In the afternoon at Leeds, Leadbeater (Deputy DG of the BNSC) made an impassioned plea to the satellite and science community to reject the idea of funds for launcher technology. Not a single voice was raised in support of him. As the debate progressed, and the BNSC position became more defensive it was suggested from the floor that the ministers view should be known. Davis (silent until now) threw a fit of pique claiming his views on launchers were those of the minister and had to be brought gently to order by Jack Leeming, who had been caretaker DG of the BNSC following Gibsons resignation.

After substantial pleading from industry (Annex A) [4]the special meeting on launchers was eventually convened on 8 July 1998 at the BNSC. Reaction Engines invited Flemings Bank to make comments on the feasibility of commercial funding in the launcher field. These comments were favourable along the lines, that once technology programs have reduced the risk demonstrably the funding of launchers would be no different to the funding of any terrestrial transport project. This contradicted the line taken by Leadbeater at the meeting, that commercial finance was impossible. These statements were omitted from the minutes of the meeting produced by the BNSC. John Francis, the economist of the BNSC at that time, confided that this was the first time such a presentation had ever been made by the finance community to the BNSC.

In October 1998 a meeting of the UKISC launcher sub-committee was held with the BNSC in which UK industry presented a comprehensive picture of its capability and reinforced its interests by producing a summary report. In February 1999 each company presented its "wish list" totalling £9 million to the BNSC for participation in the ESA FLTP [Future Launcher Technology Programme] program, and between then and early June, the UKISC members were led to believe that a ROAME [Rationale,. Objectives, Appraisal, Monitoring, Evaluation] statement was being prepared for an in depth appraisal of the launcher issue using the mechanisms recommended by HM Treasury and explained in the Treasury "Green Book". These are recognised standard procedures for the evaluation of Government policy, even when a negative decision is reached.

At the ESA Ministerial meeting in May 1999, the decision was not taken to allow the UK to participate in the FLTP program. Protests from UK industry led to assurances that the decision would be taken before the end of the year. REL took the opportunity of a new DG (Dr Colin Hicks) to restate both its anxieties about the BNSC's attitude towards launchers and the benefits of the SKYLON project to the UK (Annex B) 1.

As the ESA deadline for FLTP participation approached (11 November 1999) a meeting was held on 22 October between Lord Sainsbury (the Minister) and the BNSC on the one hand, and BAe, MMS, UKISC and the SBAC on the other. At this meeting the Minister requested a proposal for participation in the FLTP program for about £4.5 million. This was despite the fact that a ROAME proposal had supposedly been in preparation for the past seven months based on the earlier information supplied by industry.

Industry, including REL, worked hard to prepare a fresh proposal, meeting new BNSC imposed constraints regarding the diversification of the technologies proposed for development. This was presented to both the BNSC and Lord Sainsbury's office independently on 28 October under a covering letter from the SBAC (Annex C)[5]. These independent submissions were agreed because of the high level of mistrust by all of UK industry of the BNSC, and the belief that Minister would not receive unmodified information if submission had been via the BNSC alone.


There followed a long period of review and prevarication by the BNSC. The ESA deadline was passed, and meetings were held on two occasions with ESA management to discuss the possible UK participation. UK industry was denied any presence at these meetings despite the request to attend. A long silence ensued in which no indication of progress could be obtained. All of the industries and ESA brought their own form of independent pressure to try to extract information, which was "stone walled" by the BNSC. ESA was pushed into preparing two FLTP strategies, one with and one without UK participation. A decision not to participate was announced on the 13 December 1999 via the Internet (Annex D)[6] and to the press. No communication was sent to the industrial partners, and official notification was not received by the SBAC until the New Year, it having been posted by conventional mail on the 14 December and delayed by Christmas confusion.

In searching for explanations from the BNSC with regard to non-participation in FLTP (Annexes E and F)[7] they now maintain that no ROAME statement was ever prepared (Annex G) and that no formal analysis of the launcher situation was made. This is not in keeping with HM Treasury codes of practice on appraisal leading to major policy decisions.

In the handling of the FLTP proposal the BNSC appeared, as so often in the past, to make decisions in a way designed to most antagonise ESA and the industries who have invested private resources to maintain a UK position against the odds in this field.

Suivant ce memorandum, Alan Bond, Mark Hempsell et David Ashford (fondateur de Bristol Spaceplanes) on été invité à s'exprimer :

Examination of Witnesses

MR MARK HEMPSELL, Lecturer in Space Technology, University of Bristol, MR DAVID ASHFORD, Managing Director, Bristol Spaceplanes Ltd and MR ALAN BOND, Managing Director, Reaction Engines Ltd, examined.

Question Number

228 - 239

240 - 259

260 - 280

À la question 279, Alan Bond s'exprime au sujet du crédit apporté par le gouvernement, et que REL n'a obtenu qu'avec le 1er DTI SMART Award en 2002. L'évaluation indépendante, elle n'a eu lieu qu'en septembre et octobre 2010 :

[...] The Government plays an extremely important role in the attracting of any commercial finance into this field. It is a two-fold role. The first one is that the finance industry needs a peer body to take a reference from that a particular high technology area such as this is a sensible thing to take part in. The finance industry is even less well equipped than the Government or the BNSC to assess whether a technology is sensible or distinguishable from flying saucers or whatever. They generally need some peer body to take a reference. The second thing is that there is serious concern because of technology transfer issues. We have talked today about the possibility of developing these vehicles for commercial sale and I would like to come back to that point in a moment. It is not as if we are asking the Government to put up all the money to develop a space plane that is just going to be operated by a handful of government space agencies, we are talking about vehicles being sold, as in the case of Virgin, into the hands of private operators. The finance industry will not take the risk that the Government is then going to raise objections to the sale of the equipment at some later date. They want to see the Government having a stake in there and, therefore, be in a fairly compromised position towards stopping the actual allocation of them. These guidelines are very, very clear about endless discussions with the BNSC with regard to this very point. The money required from the Government is small. David Ashford and myself have some different ideas about how small, but nonetheless in absolute terms it is small, and the finance industry is prepared to come in at some later date when something like 10 per cent, as Mark Hempsell has implied already, has been taken as the rate and the risk has been taken out of the programme. The finance industry is not into taking risks, but 90 per cent of the sort of things that Reaction Engines are talking about are financed by the finance community, but that first 10 per cent has to be taken by the Government as a risk to see the perceived risk to the finance industry removed. From that point, on working with the Government, I am sure it is quite feasible to attract finance involvement in the development side of the programme, and that point has been made endlessly. [...]

Cordialement

[Geb]

Aussi, un autre document extrêmement intéressant d'un point de vue historique :

Secret files reveal US interest in UK HOTOL spaceplane

[...] The HOTOL story goes back to August 1984 when BAe, the forerunner to today's BAE Systems, unveiled a satellite launcher concept that would see an unmanned automatic vehicle use runways of "Concorde length" to carry 7,000kg (15,400lb) to low Earth orbit in its 4.6m (15ft) diameter payload bay.

ESA's member states had been looking to replace its Ariane 4 launcher and the HOTOL announcement preceded the space agency's member states' 30-31 January 1985 ministerial meeting at which a decision was taken to start preparatory work on the expendable Ariane 5 rocket.

France had proposed its manned Hermes mini space shuttle, to be launched by Ariane 5. Then UK industry minister Geoffrey Pattie wrote to Treasury chief secretary Peter Rees on 25 February explaining how French diplomatic pressure had, perversely, won support for HOTOL: "[The French] were unsuccessful [in getting support for Hermes] and irritated most other member states, who then welcomed the opportunity to express interest in [HOTOL]." The meeting's communique asked the UK to keep the agency informed of HOTOL's progress.

In December 1984 a Department of Trade and Industry (now the Department for Business, Enterprise and Regulatory Reform) space branch memo, classified restricted, had reported German interest in HOTOL and French criticism that the spaceplane would burn up as it did not have Space Shuttle-like thermal tiles.

The memo said that BAe had answered this French criticism, but such was France's reaction that a handwritten note at the bottom of the memo says: "I think we must try to avoid appearing to rival or exclude the French in discussions with them."

The project was also attracting criticism at home, with the Rugby-based project management consultant David Andrews producing an eight-page critique. Written in December 1984 for Aerospace magazine, it was sent to the DTI's space branch director. Included in Andrews' criticisms of HOTOL was that the design was optimised for the ascent, but would extend the thermal loading on descent, due to too little drag.

And, more fundamentally, the vehicle offered no capability that was not already available. But this paper did not halt government interest in the project, and a handwritten note at the bottom of Andrews' letter to the DTI says that the criticisms had been answered by BAe.

In early 1985 HOTOL was a project with some European support. But as Pattie noted in his 25 February letter: "If the UK were to take the lead in a new launcher...it would be a major change in government policy." The stage was set for a vigorous discussion between departments on what HOTOL meant for spending.

The earliest evidence of US involvement came with a 4 March 1985 DTI memo to Treasury officials about a 1 March conversation between the memo's author, DTI space branch director Andrew Nicholas, and Frank Miles, who at that time was space correspondent for the UK's ITN service.

Nicholas reports that Miles claimed to know of ongoing HOTOL technology licensing negotiations between Rolls-Royce and US propulsion company Rocketdyne, now owned by Pratt & Whitney. This memo also reported that HOTOL had run into difficulties with the Ministry of Defence at a 28 February presentation.

This difficulty is echoed in comments in an April 1985 letter marked Secret UK Eyes Alpha from the MoD's research and development department deputy controller James Barnes to the Cabinet Office's chief scientific adviser, Sir Robin Nicholson.

Barnes wrote that there was no justification for developing a UK launcher capability and no defence requirement for HOTOL vehicles, adding that it would be unlikely to enter service until the 2020s and that the "engineering problems are considerable".

He did describe the HOTOL engine as "ingenious" and "based on a secret patent awarded to Alan Bond of the UK [Atomic Energy Authority] Culham Laboratory".

Despite this MoD resistance, later that month Pattie wrote to then-defence minister Michael Heseltine proposing a two-year £3 million (in 1985 money) public-private partnership proof of concept study with £1 million from government and the remainder divided between R-R and BAe. MoD support was key because the HOTOL engine had been classified and without the military's support the engines could not be developed.

Pattie also argued that the MoD could justify its spend on the basis of "strategic capability" and that rig tests of the key technologies of heat exchangers and combustion chambers could lead to international collaboration.

Heseltine's reply is not in the archive, but three papers from the released files have been kept classified under the UK's Freedom of Information Act exemption for "formulation of government policy".

By early July 1985 more problems for HOTOL had emerged. In a letter to the MoD's engines director general, R-R technical director Gordon Lewis says that R-R wanted the Royal Aircraft Establishment's (RAE) propulsion group involved and that the company would not invest its own money in HOTOL engine development. Yet for the £3 million programme, £1 million was supposedly coming from R-R.

The third quarter of 1985 saw work on the BAe/R-R two-year proof of concept study proposal and by November the case for US collaboration was getting stronger.

At an 8 November meeting between the RAE and the DTI's space branch it was reported that R-R now called its HOTOL engine Swallow and the company was seeking US ramjet data. R-R also expected to need US nozzle technology.

That month minutes of a conversation between then-prime minister Margaret Thatcher's minister without portfolio Lord Young and US president Ronald Reagan's science adviser George Keyworth were also sent to the DTI.

The minutes show that the USA was interested in collaborating on a hypersonic aircraft like HOTOL, that Pattie had attended a meeting in the USA for nations interested in such a project and that a "prototype could be flying as early as 1990".

But despite Keyworth's offer the UK government files show that neither the BAe or the MoD wanted US involvement, wary of the UK becoming too junior a partner while R-R saw a need for transatlantic co-operation.

In November 1985 an RAE assessment of the proof-of-concept study proposal was downbeat. The RAE thought that HOTOL would take up to 20 years to develop, not the 12 years BAe and R-R were proposing. It said there was a need for £750 million for the six-year definition phase based on a total project cost of £5 billion, in 1985 money.

It also said there was only £1.5 million pledged of the proposed two-year study's £2 million industry funding, with £1 million from BAe and £485,000 from R-R, and that an early decision was needed to ensure funding for a post-proof of concept, pre-definition phase feasibility study expected to cost £25 million.

Despite the two-year project proposal, the government knew that further European decisions on launchers would be taken in 1987. Full development of Ariane 5 was approved in November of 1987 and it flew successfully 10 years later.

In the first quarter of 1986 the UK government approved the two-year study, but by 1989 the future of HOTOL was looking bleak and France's Hermes mini shuttle eventually suffered the same fate and was cancelled.

In many respects the seeds for HOTOL's cancellation were sown at the beginning, with uneven support within UK government and its industrial partners, little prospect of European engagement and only the US government ready to embrace the project for its own ends.

Cordialement

[Geb]

Enfin, pour compléter la série, un dernier vers le deuxième chapitre d'un bouquin concernant la période 1984 (HOTOL rendu public) et 1994 (première mouture du Skylon dans sa version C1) :

Major efforts in the U.K. (1984–1994)


Même si l'article n'est pas particulièrement exact d'un point de vue technique (il présente le RR545 comme un LACE avec séparation de l'oxygène de l'air et liquéfaction), on apprend par exemple que British Aerospace avait continué le développement du HOTOL (puis HOTOL Interim et enfin RADEM) avec des entreprises russes (et sans Alan Bond, impliqué dans la définition du futur Skylon C1 avec REL entre 1990 et 1994).

Cordialement

[Geb]

Bonsoir,

À cause de ITAR, Reaction Engines a bien exprimé le fait que toute implication d'une entreprise américaine serait rendue trop longue et/ou coûteuse.

L'édition de décembre 2009 du magazine ASCEND comporte un article sur le sujet :

U.S. ITAR REGULATIONS MAY STOP NASA EXAMINING REVOLUTIONARY ROCKET PLANE

Bonne lecture.

[Geb]

Bonjour,

Le système antigivrage a été expérimenté dès le premier investissement privé conséquent (60 000 livres par Paul Portelli en mars 2001), dans une des plus petites soufflerie cryogénique du Royaume-Uni, construite par REL sur leur site de Culham.

Voilà l'article de Rob Coppinger (le journaliste de la BBC qui nous écrit de si passionnants articles sur le Skylon) dans lequel j'ai trouvé cette information, daté du 1^er novembre 2001 :

Ready for lift-off

[...] Some funding has come in from a surprising source, in the form of backing from Paul Portelli, the owner of a London ceramics supplier, World’s End Tiles. Portelli, a space enthusiast, has even hung a model of Skylon in his showroom, and is understood to have contributed some tens of thousands of pounds to the project.

Funding

Obviously, more is needed, though the focus now is on building a small-scale laboratory bench demonstrator of the pre-cooler concept by next summer, which will cost around £60,000. [...]

L'article cite également Gerald Carroll, patron de l'entreprise de construction Carroll Corporation, ainsi que l'intérêt de GEC/Marconi, qui, en 1997, aurait proposé 400 000 livres sterling sous réserve que la même somme soit investie par le gouvernement britannique (offre que le British National Space Centre a refusé).

En faisant des recherches sur GEC/Marconi, j'ai trouvé un passage intéressant dans un pdf daté du 30 mars 1995 :

[...] the team which worked on Interim Hotol and related concepts at British Aerospace Space Systems is now part of Matra Marconi Space (MMS) Space Systems, following a takeover last year [...]

Avant d’investir une somme indéterminée (peut-être 60.000 livres sterling donc) dans la société Reaction Engines en mars 2001, Paul Portelli (1943-2007), patron de la société World’s End Tiles avait demandé à la fin de l’année 1997 une réplique à l’échelle 1/18e du Skylon C1 a disposer dans son showroom.

http://www.smallspace.demon.co.uk/Mo...lon/skylon.htm

Cordialement

[Geb]

Voilà l'article de Rob Coppinger (le journaliste de la BBC qui nous écrit de si passionnants articles sur le Skylon)

Remplacer "de la BBC" par "de Flight Global".

[Geb]

Bonsoir,

J'ai trouvé un autre article assez complet sur le Skylon, daté du 13 juin 2011 :

Skylon: ready for takeoff?

Un passage que je voudrais discuter :

While company estimates put the per-flight operating costs as low as $9.5 million, that requires a flight rate of 70 missions a year; costs when the vehicle enters service will be on the order of $30–40 million a flight, according to the Reaction Engines web site. That could put the vehicle at a competitive disadvantage to some expendable vehicles. Assuming a capacity of 15 tonnes to LEO, initial Skylon costs would be $2,000 to nearly $2,700 per kilogram. By comparison, SpaceX’s Falcon Heavy, with a capacity of 53 tonnes to LEO and a projected cost of $80–125 million per launch, would come in at $1,500 to $2,350 per kilogram. Moreover, development of the Falcon Heavy is expected to cost a small fraction of the Skylon’s projected cost, and it could enter service as soon as 2013, years before Skylon will be ready in even the most optimistic scenario.

Déjà le 28 février 2000, Reaction Engines Limited avait de quoi nuancer ces propos (au message #72) :

Memorandum submitted by Reaction Engines Ltd

The cost of access to space with ELVs is prohibitive. Typically, the launch of a payload to low Earth orbit (LEO) at around 300 km costs approximately $10,000 per kg. The cost transferring a payload to geostationary Earth orbit (GEO) at about 36,000 km costs five times this. To put this into perspective, the cost of anything in space is at least as expensive as gold.

The following is a most important point and should be noted carefully. Because spacecraft hardware in space has such a huge added value due to the launch cost, its owners cannot afford it to fail. It is therefore essential to add Quality Assurance (QA) to a level commensurate with the investment cost of the launch. The added reliability drives up the cost of the spacecraft therefore to at least equal the launch cost, and may exceed it by up to 50 per cent. With such high investment now at stake insurance of the launch and the spacecraft is needed, which adds typically a further 20 per cent to the cost.

[...]

It is necessary to be specific about launch costs since many figures are quoted by different sources resulting in much confusion. Up front, there is the price that a customer pays for his payload to fly. This is generally only a small part (30 to 40 per cent) of the actual cost which has been incurred in getting his payload to orbit. Part of the actual cost is the procurement cost of the vehicle. However this is generally only the production cost, the development cost having been written off by the taxpayer. There is then the cost of transport to the launch site and the vehicle assembly and preparation, including the interfacing of the payload. Some of this may be borne by the launcher operator, and passed to the customer while the infrastructure costs of these operations will be carried by the taxpayer. Finally the range operations will be carried mostly by the taxpayer. The "cost" normally quoted is that which the customer pays (ie the ticket price), while the real launch cost, counting the taxpayers contribution through the space agencies is about three times the ticket price.

Je ne suis pas sûr que comparé la Falcon Heavy avec le Skylon soit honnête dans ce contexte.

Cordialement

[Geb]

Bonjour,

On peut aussi voir les prix pratiqués par SpaceX comme un allié pour lever les 10 à 15% de fonds publics dans le programme de développement du Skylon (à travers l'ESA et Arianespace).

More about Skylon development

Hempsell says "SpaceX is closer to what we are doing but their solution and route to market is very different". I think they need SpaceX to succeed in undercutting the launch prices of Arianes V and other ELVs to convince the ESA/Arianespace establishment to forget the Ariane VI and go with a radical solution. Those "pre-orders" are only going to arrive if ESA is convinced that the Skylon is their best hope to compete with the new lower cost systems from SpaceX and others like Blue Origin.

Cordialement

[Geb]

Bonsoir,

Retardées jusqu'à aujourd'hui "pour cause de maladie", les nouvelles du mois de juillet ont enfin été publiés sur le site de Reaction Engines Ltd :

News Update - July 2011

Information importante, le projet STRICT (pour Static Test Rocket Incorporating Cooled Thrust Chamber), qui faisait partie du programme de développement en 3 volets financé en partie par l'ESA est terminé.

Le programme STRICT a pour but d'expérimenter la tuyère à expansion/déflection pour peut-être remplacé la tuyère classique actuellement choisie pour le Skylon.

Les conclusions préliminaires du programme STERN (Static Test of Expansion/Deflection Nozzle) qui l'avait précédé était les suivantes :

[...] preliminary results suggest that the removal of the restriction of area ratio on SSTO nozzles has a greater impact on payload gain than the altitude compensation itself [...]

Cela permettrait donc de raccourcir les cols des 4 tuyères du SABRE, économisant d'après REL environ 500 kg (qui pourrait être ajouté à la charge utile embarcable) et les meilleurs performances à basse altitude permettrait de raccourcir en même temps la piste de décollage de 500 mètres.

Cordialement

[Geb]

Entre 1982 et 1988, le programme HOTOL avait vu naître 10 configurations différentes, de la A jusqu'à la J. Le véhicule étant mal conçu dès le départ, la masse au décollage n'avait cessé d'augmenter, de 162 tonnes à 567 tonnes, avec respectivement 7 tonnes et... 6,3 tonnes de charge utile en orbite.

La charge utile calculée du Skylon C1 à 300 km sur une orbite équatoriale avec un départ depuis Kourou était finalement descendue, de 12 tonnes en 1994 (objectif jamais atteint) à 10 275 kg.

Aujourd'hui le Skylon en est à sa 4e configuration, le Skylon D1. En août 2010, REL affirmait au sujet de la charge utile maximale du Skylon D1 :

The performance analysis for the SKYLON D1.5 design estimated it could deliver a 15 tonne payload, with a 2.5 tonne margin (i.e. 17.5 tonnes total), for a 325 tonne vehicle take-off mass. The 2.5 tonnes was in addition to the mass margins contained within the vehicle’s dry mass estimate.

Avec une marge de 2,5 tonnes sur la charge utile en plus des autres, c'est donc que les concepteurs du Skylon sont encore plus prudents qu'auparavant (la marge du Skylon C1 était de 1,2 tonnes).

Si on veut voir les choses d'une façon (exagérément) optimiste, on peut tout aussi bien dire que le Skylon D1.5 pourrait satelliser jusqu'à 18 tonnes de charge utile en orbite basse (en ajoutant les 500 kg de la tuyère à expansion/déflection). Une estimation que les concepteurs ont prudemment ramenée à 15 tonnes (leur objectif pour satelliser les satellites télécoms Alphabus les plus gros avec un Skylon Upper Stage).

Cordialement

[invite15b2900e]

Entre 1982 et 1988, le programme HOTOL avait vu naître 10 configurations différentes, de la A jusqu'à la J. Le véhicule étant mal conçu dès le départ, la masse au décollage n'avait cessé d'augmenter, de 162 tonnes à 567 tonnes, avec respectivement 7 tonnes et... 6,3 tonnes de charge utile en orbite.

La charge utile calculée du Skylon C1 à 300 km sur une orbite équatoriale avec un départ depuis Kourou était finalement descendue, de 12 tonnes en 1994 (objectif jamais atteint) à 10 275 kg.

Aujourd'hui le Skylon en est à sa 4e configuration, le Skylon D1. En août 2010, REL affirmait au sujet de la charge utile maximale du Skylon D1 :



Avec une marge de 2,5 tonnes sur la charge utile en plus des autres, c'est donc que les concepteurs du Skylon sont encore plus prudents qu'auparavant (la marge du Skylon C1 était de 1,2 tonnes).

Si on veut voir les choses d'une façon (exagérément) optimiste, on peut tout aussi bien dire que le Skylon D1.5 pourrait satelliser jusqu'à 18 tonnes de charge utile en orbite basse (en ajoutant les 500 kg de la tuyère à expansion/déflection).

Cordialement

Salut
votre article m'interesse pour une autre raison
pourriez vous me repondre malgré tout?
merci:
1UK ton = 1016KG
1US ton = 907.2KG
votre article est en anglais je suppose quoi? US ou UK
1 ton science = 1000KG

[Geb]

Bonsoir,

Tous les papiers de REL utilisent la tonne internationale, la tonne métrique de 1000 kg.

Cordialement

[invite15b2900e]

Grand bonsoir mademoiselle , monsieur,
Je peut vous dire un très très grand merci
sans aucune exagération et tout à fait sincèrement

Bonne soirée

[invite15b2900e]

Bonsoir,

Tous les papiers de REL utilisent la tonne internationale, la tonne métrique de 1000 kg.

Cordialement

Salut
tiens mais à propos et si mes souvenir sont exacts ce ne serait pas la premiere fois qu'il y aurait eut confusion entre la tonne metrique et celle U.S. sur du materiel sensible
enfin je me trompe peut être ...mes sources après tout valent celles de ma vague mémoire et d'un "oui dire"
ce serait interessant de savoir sûrement pour vous
(je dit cela pour vous rendre service bien sûr)

Bonne soirée

[Saint-Sandouz]

tiens mais à propos et si mes souvenir sont exacts ce ne serait pas la premiere fois qu'il y aurait eut confusion entre la tonne metrique et celle U.S. sur du materiel sensible

C'est une sonde américaine sur Mars (j'ai oublié laquelle) dont une partie des paramètres avaient été entrés en unités impériales. Beau flop.
Pourquoi les Américains restent scotchés ce système (si on peut parler de système) alors que les British sont passés au système métrique, ça me dépasse.

ND

[invite15b2900e]

C'est une sonde américaine sur Mars (j'ai oublié laquelle) dont une partie des paramètres avaient été entrés en unités impériales. Beau flop.
Pourquoi les Américains restent scotchés ce système (si on peut parler de système) alors que les British sont passés au système métrique, ça me dépasse.

ND

Ben en fait moi pas. Regarde c'est pas imperial ça?
et quand tu songe que sa progeniture remplacera l'espece humaine!
alors là..............

http://3.bp.blogspot.com/_p_3mlOIkFe...ront+grill.jpg
le horlà

salut allez tu verra tout s'arrangera

[Carcharodon]

salut allez tu verra tout s'arrangera

Ce qui devrait s'arranger assez vite, c'est le fait que tu commences a comprendre que tu es sur un forum scientifique et non pas sur un chat de CM1 ou une réunion tupperware.

Il serait bon que tu identifies mieux tes lieux d'intervention afin d'arrêter ta pollution de cours d'école.
C'est ça, nous rendre service.

[Geb]

Bonsoir,

Pour en revenir au sujet, j'ai trouvé deux autres articles récents sur le Skylon.

Tout d'abord, une interview de David Parker, "directeur de la technologie, de la science et de l'exploration" de l'agence spatiale britannique, durant laquelle il cite le Skylon :

David Parker, director of space science at the UK Space Agency

What area of space science are you particularly interested in at the moment?
Right now, I’m very interested the progress that Reaction Engines is making with its Skylon spaceplane. I’m in lots of discussions with them about how that is going to be taken forward. We’re facilitating discussions with the European air worthiness authorities, thinking about how you operate a spaceplane from the regulation and insurance point of view, because a Mach 5 spaceplane without a pilot [raises] some interesting questions about flying things around in airspace. There are a lot of ’ifs’ with Skylon. But there are some very smart guys working on it, I have to say. As well as some good financial backers. It’s a really exciting project for the future.

Qui sont ces "good financial backers", mystère...

Le deuxième article citant le Skylon à pour sujet les concepts aérobies et les lanceurs réutilisables :

Current strategies towards air-breathing space launch vehicles

Bonne lecture.

[Geb]

Bonjour,

Les tests du modèle 9% du precooler du moteur SABRE se déroulent comme prévu d'après les nouvelles du mois d'août sur le site de Reaction Engines Limited :

News Update - August 2011

Ils devraient se poursuivre jusqu'à la fin de cette automne.

Quelques sites qui ont récemment consacré un article au Skylon :

Spaceplane engine tests under way

Tests on "Skylon" aircraft's rocket motor proceed

Je ne sais pas pourquoi il s'obstine à croire que la charge utile maximale est de 12 tonnes au lieu de 15. Que le Skylon fait près de 90 mètres au lieu de 84 et pourtant il parle bien de 6 tonnes en GTO, qui est la capacité du Skylon Upper Stage avec la version 15 tonnes du Skylon (la seule qui sera développée) en mode réutilisable. Le Upper Stage peut satelliser 6,25 tonnes en GTO puis être récupéré ou 8,25 tonnes et ne pas être récupéré.

Cordialement