Ariane 5 and Hermes

[spd405]

What was the reasoning behind the cancelling of the Hermes spaceplane?

 

[najab]

Rapidly rising cost estimates. Lack of political will.

 

[botch]

Just as well I suppose; Ariane 5 hasn't demonstrated exceptional reliability thus far.

 

[mrmorris]

Also rapidly reducing capabilities from the original specs.

 

[elguapoguano]

The Europeans don't have the political will to build thier own manned craft. Plus, Ariane 5 has had delays and problems, plus the weight of the Hermes was growing so fast that the Ariane 5 couldn't launch it anymore. <div class="Discussion_UserSignature"> <font color="#ff0000"><u><em>Don't let your sig line incite a gay thread ;>)</em></u></font> </div>

 

[gunsandrockets]

Why? The old bugaboos of weight and cost growth.<br /><br />The Russians are preying on the old French ambitions to have their own manned space-plane by proposing a winged version of the Kliper spacecraft which could land on a conventional runway.

 

[chris_in_space]

The reason?<br /><br />Essentially lack of political will. Indeed curently the Europeans don't have to high ambitions on manned space flight programs. Even without developping its own orbiter the manned space program is secondary (good example for this is the ISS: there are not too many Europeans who fly to the ISS... and the contribution is also limited: only one space module). So Europe actually never had high ambitions for a manned space flight program...<br />

 

[spd405]

Could Ariane 5 be engineered to have 4 SRB's and if so any guestimates on performance?

 

[chris_in_space]

To answer your questoin I think yes it should be technically possible. But I think it's highly unprobable it will ever happen. As to performance estimates to my knowledge there are no studies on it that I know of, so I don't have any performance estimates.<br /><br />But I'd like to come back to this and other discussions on space.com where the idea has came up that 4SRBs is the ultimate solution, wheter for the shuttle derived launchers or others. I strongly disagree with this. I don't think that adding SRBs is the good way. To expalin why one has to go back to basic rocket science and remember that what is important to go to orbit is speed. And speed is acquired by Isp not by thrust. And the problem is SRBs are terribly poor for Isp. They are extremly good for thrust but it's not thrust that's going to get you to orbit. For me SRBs are only the secondary thrusters that help the rocket get up from the ground and pass you through the thick atmosphere. The really good think is the little engine between the boosters since it's that that gives you much Isp. <br />So I disagree that SRBs everywhere is the ultimate solution. For me the good way is to look at engines with the highest Isp, if necessary bundle a couple of such high Isp engines together and if they are still too weak to lift off then strap some boosters around them. That's the way it should go not the other way round.<br /><br />Btw it would also pose another problem to have 4 SRBs for human space flight, problem which is also related to the high thrust. Due to this high thrust the g force at start will be very high. One would have to compute if the g force would not be too high for people to sit inside.<br />

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>The Europeans don't have the political will to build thier own manned craft.<p><hr /></p></p></blockquote><br />I'd say they simply make wiser desicions about their investments. <br />Building a "spaceplane" under government supervision and guidelines hasnt been proven exactly spectacular success in the past, so maybe they simply learned from others mistakes.<br />In a current situation, if you really want manned orbital flight capabilities, buying services from Russians is definitely more cost-effective and perhaps from Chinese after a short while. <br />A decade later its probably even more effective to simply purchase tickets from British Spacelines or somesuch, meanwhile investing in supporting the newcompers in space industry to enhance the market capabilities.

 

[space_dreamer]

Hermes was meant to be a rival the STS (not on the same scale but...) the US had a space plane so the French wanted a space plane to. That why us Brits wanted nothing to do with it, "Why spend billons of pounds for French pride".-Margaret Thatcher. <br /><br />For a wile there was talk of a ESA space station (see pic) But we got invited to join the freedom program in stead, this option was thought to be cheaper and quicker!!! LOL!

 

[spd405]

That why the Brits wanted nothing to do with it, Billons of pounds for French pride. <br /><br />Ah yes, the Ken Clark 'we're not going to pay for jonney foreigner to go a play in space' line.<br />

 

[space_dreamer]

We should have developed HOTOL or better still SKYON, I was lucky enough to see a wind tunnel test of SKYON in 1996. Such an amazing concept! The space flight world would be completely different if the UK had built that SSTO space plane. It’s still better than anything on the drawing board now!

 

[space_dreamer]

if only...

 

[spacefire]

how would that thingy make it BACK from orbit? is it plated with unobtanium? <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[spacefire]

check out Hermes in 3d here<br /><br />http://www.dassault-aviation.com/gb/media/anim3d/hermes.cfm#<br /><br /><br />my only qualm with the design is that it's not a lifting body. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[nacnud]

From Reaction engines<br /><br />Material Construction <br /><br />Skylon's fuselage and wing load bearing structure is made from carbon fibre reinforced plastic and consists of stringers, frames, ribs and spars built as warren girder structures. The aluminium propellant tankage is suspended within this, free to move under thermal and pressurisation displacements.<br /><br />The external shell (the aeroshell) is made from a fibre reinforced ceramic and carries only aerodynamic pressure loads which are transmitted to the fuselage structure through flexible suspension points. This shell is thin (0.5mm) and corrugated for stiffness. It is free to move under thermal expansion especially during the latter stages of the aerodynamic ascent and re-entry.<br /><br /><br />Re-entry <br /><br />During re-entry, which occurs at an altitude between 90 to 60km the heat is radiated away from the hot aeroshell. Heat is prevented from entering the vehicle by layers of reflecting foil and the low conductivity shell support posts. Liquid hydrogen is evaporated in the main tanks, passed through thermal screens to intercept the small residual heat leak and then vented overboard.<br /><br />For more read the paper on the topic, Application of Carbon Fibre Truss Technology to the Fuselage Structure of the SKYLON Spaceplane (PDF)<br />

 

[spacefire]

thanks for the paper, I'll have something to do at work today! <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[nacnud]

There are lots more at http://www.reactionengines.co.uk/main.php?content=downloads<br /><br />Enjoy!

 

[chris_in_space]

space_dreamer,<br /><br />You're sure your ESA space station image is a serious one or just an artist view, cause the space station seems to be attached at the engines of Hermes. So how would the astronautes go from one to the other. Through the engine?<br /><br />Don't think that Hermes was ever considered very seriousely in Europe and even in France. And btw speaking of the French they found out long ago that human space flight is too expensive for the moment; just look at the French part for human space flight in the ESA budget. It's quite low considering that in allmost all other areas the French part is the highest among ESA members...<br />

 

[nacnud]

Hermies didn't have engines there, its more like a top mounted mini Buran with no cargo than the STS

 

[spacefire]

yeah, check the website I provided. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[spd405]

Ariane 4 used 2-4 Liquids or Solids in various combinations, anyone know the reasoning behind 2 large Solids for A5? <br /><br />If A5 didn't originally have to launch Hermes as well as satellites, what kind of configuration would have been used?

 

[dreada5]

<blockquote><font class="small">In reply to:</font><hr /><p>Indeed curently the Europeans don't have to high ambitions on manned space flight programs. Even without developping its own orbiter the manned space program is secondary (good example for this is the ISS: there are not too many Europeans who fly to the ISS... and the contribution is also limited: only one space module). So Europe actually never had high ambitions for a manned space flight program... <p><hr /></p></p></blockquote><br /><br />Where are you from Chris?<br /> <br />Europe may not have the political will and hence the money, but ESA along with space enthusiasts here in Europe are striving to get involved in more manned missions. Why else do we have the Aurora Programme? Why else are we cooperating with NASA on Bush's new space vision to the Moon/Mars? Why else are we working with Russia on the Kliper spaceplane? Why else do we have astronaut corps? Why else are we uprating the infrastructure at French Guiana spaceport. Advanced Soyuz will start showing up in Kourou in 2006!! Hopefully we'll soon have manned capability option but without the large development costs just like the Chinese in the short term and Russia's Kliper spaceplane in the long term!! <img src="/images/icons/smile.gif" /><br /><br />Regarding the ISS, the US and Russia are the most experienced space-faring nations hence they provide the backbone, Japan, Europe etc have made all the final contribution necessary to maximise such a station as ISS. Besides I think its good that ESA only produced one module for the station, for one I don't think NASA could handle anything more right now. ESA struggles just to get our astronauts to ISS because of the state of the station. Not that we aren't keen to increase the flow ESA astronauts to and from the station.<br /><br />It does seem that ESA will in time specialise in robotic missions but although europeans may not be as enthusiastic about manned spaceflight as the US, WE DO have an interest hence our inve

 

[nacnud]

Hi, can you shorten that last link please link <br /><br />Thanks