A low cost, all European, manned launcher.

[Urwumpe]

Have you accounted for the modifications to the thrust-structure, and added power requirements?

No. It is all done simple. I work on a Java tool for such more complex calculations, but to be honest, it is only getting ahead, when RGClark claims a bit too much. :lol:

I would also have to remove additional mass for supporting the solid rocket boosters, add additional mass for having hold down, I would also need to add additional helium tanks to the rocket, etc.

 

[RGClark]

Using those numbers, you would end up with an acceleration of 13,5 G just prior to MECO.

The Vulcain's are not throttleable. Perhaps they can be made to be so. But if not, you could shut down one of the engines late in the flight when the vertical thrust portion of the flight is over. This would be a max of 6.75 g's.
I found this when looking up ref's on g-tolerance:

http://yarchive.net/space/science/g_tolerance.html

Judging by this table, the tolerance at this number of g's would be in the range of a couple of minutes. But it would actually only have to be for a few seconds at this high range since you would still have a significant amount of fuel remaining even with say 15 seconds burn time left.
BTW, you might find it amusing to read about the experiments done on chickens for the effects of long term exposure to moderate g's conducted in centrifuges.


Bob Clark

 

[Urwumpe]

Remember that you can't shut down one of two engines for g-limiting. This would give you control problems (you would need to quickly change attitude of the rocket to compensate the loss of thrust on one side, that is not as easy as it sounds)

If you would have three Vulcain engines, you could shutdown the outer engines with less problems.

Making an engine throttleable is pretty complicated and expensive. You would need a new injector as starting point, which can also atomize the fuel after injection pressure dropped (or prevent this drop by shutting down the supply of one propellant component for a part of the injector nozzles). Then, when you have this, you would need a new turbopump system that can be controlled over a wider range of throttle settings. Deep throttle is a real challenge, especially for bigger rocket engines. It is already hard to prevent damaging vibrations for smaller engines at less than 50% throttle.

The main problem is, that even today, computer models are not adequate to simulate the acoustics of a combustion chamber accurately. You need testing and sometimes it becomes destructive testing.

 

[RGClark]

Remember that you can't shut down one of two engines for g-limiting. This would give you control problems (you would need to quickly change attitude of the rocket to compensate the loss of thrust on one side, that is not as easy as it sounds)
If you would have three Vulcain engines, you could shutdown the outer engines with less problems.
Making an engine throttleable is pretty complicated and expensive. You would need a new injector as starting point, which can also atomize the fuel after injection pressure dropped (or prevent this drop by shutting down the supply of one propellant component for a part of the injector nozzles). Then, when you have this, you would need a new turbopump system that can be controlled over a wider range of throttle settings. Deep throttle is a real challenge, especially for bigger rocket engines. It is already hard to prevent damaging vibrations for smaller engines at less than 50% throttle.
The main problem is, that even today, computer models are not adequate to simulate the acoustics of a combustion chamber accurately. You need testing and sometimes it becomes destructive testing.

The loss of thrust on one side could be handled by gimbaling the engines. Plus the fact the rocket has to be tilted over anyway when you are transitioning to the horizontal thrust portion of the flight.

Bob Clark

 

[Urwumpe]

The loss of thrust on one side could be handled by gimbaling the engines. Plus the fact the rocket has to be tilted over anyway when you are transitioning to the horizontal thrust portion of the flight.

Bob Clark

Only tilting the last remaining engine is not enough, you would have zero torque then, but accelerate away from course. You also need to rotate the whole rocket in the process. In emergency, this is tolerable, but in nominal flight, you rather want to avoid having to move rapidly, so the increasing torque does not buckle your rocket.

 

[RGClark]

My primary complaint about the published plans for the ESA
next generation launcher and/or Ariane 6 was that the liquid fueled
version was to use a single new expensive staged-combustion engine at
about twice the thrust of the Vulcain.
I was therefore pleased to see that there is now being considered a
version that will use two engines on the core:

CNES, ASI Favor Solid-Rocket Design For Ariane 6.
By Amy Svitak.
Source: Aviation Week & Space Technology.
October 15, 2012.
Amy Svitak Naples, Italy, and Paris.
"Bonnal says CNES is preparing wind-tunnel tests to adjust the margin
policy, and pressure oscillation has been assessed for different
flight phases.
"Similar to the P1B, the all-liquid H2C would use up to six strap-on
boosters to carry as much as 8,400 kg to GTO. Twin main engines,
capable of 150 tons of vacuum thrust derived from the Ariane 5's
Snecma-built Vulcain 2, would comprise the H165 first stage, which
would be topped by a 31-ton cryogenic upper stage, he says. "
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_10_15_2012_p26-505016.xml&p=3

However, it seems to be the nature of governmental space agencies to
always want to go grandiose, like NASA. Instead of incurring the cost
of increasing the thrust of the Vulcain 2, why not use the same ones,
use a smaller upper stage (31 tons really??) and go with the smaller
Ariane 5 "G" version of the core stage?
As I discussed before, judging by the Japanese example with
the H-II rocket of adding on a second cryogenic engine, this
modification of the Ariane 5 core to use two Vulcains probably can be
done in the $200 million range. Then there really is no need to
continue talking about billion dollar development programs for the
Ariane 6.
Indeed with the recent ESA decision to engage in the development of
the Ariane 5 ME, this modification to the Ariane 5 core to use two
Vulcains is so comparitively low cost it could be done at the same
time as the Ariane 5 ME development. That is, you could have both
the Ariane 5 ME and the Ariane 6 in the same time frame.
Another point, again as I discussed before, the most
important result of following this approach is that it would result in
a manned capable launcher in a short time frame. Even if you are
skeptical of the SSTO version, just using the current, small, ca. 10mT
gross mass upper stage, or even smaller ones from the earlier versions
of the Ariane, you could have your manned launcher without the solid
side boosters. This key advantage I still haven't seen discussed but
obviously it would a great benefit in producing support among the
European public and the politicians, who hold the ESA purse strings.


Bob Clark

Note: the attached image did not appear in the AV Week article, at least it doesn't in the current version online. I found it after a web search. It does show two engines on the liquid fueled version of the Ariane 6 core.

 

[RGClark]

That Av Week article says the ESA is favoring the solid, first stage solution to the Ariane 6. This article in Spaceflightnow makes clear that is largely a political decision, not because of its capabilities:

European ministers decide to stick with Ariane 5, for now.
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: November 21, 2012

An initial design assessment by CNES - the French space agency - this year concluded the Ariane 6 rocket should consist of a solid-fueled first stage motor and a cryogenic liquid-fueled upper stage based around the next-generation Ariane 5's Vinci engine.
The concept would build upon both the Ariane 5 and lightweight Vega satellite launcher, which debuted in February and is powered by solid rocket motors. Such a design would ensure high industrial involvement from France, Germany and Italy, the three largest contributors to Europe's rocket programs. "At the moment, we see synergies between both Ariane 5 and Ariane 6, as well as Vega and Ariane 6," said Enrico Saggese, president of the Italian Space Agency, in an interview Wednesday.
Return-on-investment in the form of industrial contracts and jobs is one of the most important factors guiding decisions on European space programs.
http://spaceflightnow.com/news/n1211/21ariane/#.ULe6wRgreWs

The most important advantage of the all-liquid solution is that it could serve as a manned flight capable launcher without the solid side boosters. Entering in some numbers in Schilling's Launch Performance Calculator, I get in the range of 6,000 kg to LEO using the numbers given in the Av Week article for the all-liquid solution as a SSTO, and in the range of 10,000 kg to LEO using two stages.




Bob Clark

 

[RGClark]

Saw this Russian language launch performance program mentioned on NASASpaceFlight.com:

Поезд в космос - Главная страница.
http://traintospace.narod.ru/

Bing Translator gave me this for the first link on that page (worked a little better than Google Translator):

Sputnik Program Help.
http://www.microsofttranslator.com/...aintospace.narod.ru/sputnik/sputnik-help.html

Anyone know how to operate it? I'd like to apply it to the Ariane 6 liquid-fueled core version with upgraded twin Vulcain II engines, both as a single stage and with an upper stage. Refer to image in post #66 above.


Bob Clark

 

[SiberianTiger]

Funny, it will work only if full Russian locale installed. I can't even run the program properly on my office PC with American locale.

 

[RGClark]

...
Another point, again as I discussed before, the most
important result of following this approach is that it would result in
a manned capable launcher in a short time frame. Even if you are
skeptical of the SSTO version, just using the current, small, ca. 10mT
gross mass upper stage, or even smaller ones from the earlier versions
of the Ariane, you could have your manned launcher without the solid
side boosters. This key advantage I still haven't seen discussed but
obviously it would a great benefit in producing support among the
European public and the politicians, who hold the ESA purse strings.


Bob Clark

Note: the attached image did not appear in the AV Week article, at least it doesn't in the current version online. I found it after a web search. It does show two engines on the liquid fueled version of the Ariane 6 core.

The ESA needs to release to the European public the LEO payload capability of the twin-Vulcain solution for the Ariane 6. The image above gives only it's payload to [ame="http://en.wikipedia.org/wiki/Geostationary_transfer_orbit"]GTO[/ame], not to LEO, in the configuration without solid rocket boosters. The configuration without the solids is the appropriate one since there still is a distrust in the industry for manned flights using solids since they can not be shut down. Note it would also be less costly to man-rate without the solid rocket boosters.

Looking at some other launchers however, we may be able to estimate the payload to LEO. You see for the [ame="http://en.wikipedia.org/wiki/Ariane_5"]Ariane 5[/ame], [ame="http://en.wikipedia.org/wiki/Atlas_5"]Atlas V[/ame], and [ame="http://en.wikipedia.org/wiki/Delta_IV"]Delta IV[/ame], the payload to LEO is about twice that to GTO, more or less. Twice the 2,200 kg payload to GTO for the liquid-fueled sans solids version of the Ariane 6 would be 4,400 kg. Then we may estimate the payload to LEO to be in the 4,000 kg to 5,000 kg range.
Note this would be well sufficient to launch a small size capsule about half-size to the SpaceX Dragon. The Dragon is at a dry mass of about 4,000 kg, so half size is about 2,000 kg, but we also want to reserve mass for the launch escape system (LAS). A 4,000 kg to 5,000 kg payload capability should be sufficient even including a LAS.

In regards to cost, note the Dragon cost $300 million in development as privately developed. As privately developed this half-size capsule should be even less, perhaps even half that to $150 million.
There is also the question of man-rating this liquid-fuel Ariane 6 launcher. We might make a comparison to the man-rating of the Atlas V, which only cost a few million dollars.


Bob Clark

 

[RGClark]

Just saw this:

CNES Design Team Sets ‘Triple-seven’ Goal for Ariane 6.
By Peter B. de Selding | Jan. 2, 2013
http://www.spacenews.com/article/cnes-design-team-sets-‘triple-seven’-goal-for-ariane-6

You'll need to do free registration for temporary access to read the article.

From the article:

...after months of hard selling that saw them pitted against much of France’s industry, CNES officials last year convinced Fioraso that Ariane 6 — less expensive and less powerful than Ariane 5, and carrying just one satellite at a time to orbit — is the way of the future.
The design of the rocket — two solid-fueled lower stages and a cryogenic upper stage, plus solid-fueled strap-on boosters — was frozen Nov. 21 during a meeting of ESA government ministers.ESA Launcher Director Antonio Fabrizi said this design, and no other, is what ministers approved.

and:

Ariane 6 has been conceived from the start as a “next-generation” rocket that in many ways looks like a throwback — more of a less-expensive Lockheed Martin Atlas 5, or a Proton launched from the equator. Ariane 5 can do more things for more customers.
But if it meets its design goal, Ariane 6 will reach a financial equilibrium that has eluded Ariane 5. CNES officials say economic criteria account for 43 percent of the design decisions made for the rocket, with technical criteria accounting for just 30 percent.
The remaining 27 percent of the design choices are being made on the basis of Europe’s existing industrial capacity.
French industry is responsible for around 50 percent of the construction of Ariane 5. Eymard said the agency assumes France will carry about the same load for Ariane 6.
Beyond the French contribution, all bets are off. CNES has penciled in Germany at 25 percent, and Italy at 10-15 percent. The Italian share should be relatively easy to secure because Italy already is heavily involved in production, with Snecma of France, of the solid-fueled strap-on boosters used on the Ariane 5 rocket. Italy is also the lead investor in the new Vega small-satellite launcher, which made its inaugural flight in early 2012.
Because of the all-but-guaranteed work share of Italian industry in the Ariane 6 solid-fueled stages, the Italian government is not likely to resist taking its 10-15 percent stake despite its public-debt crisis.
Ensuring German industry sufficient work will not be as straightforward, European government and industry officials said.

This article shows the difficulty the ESA will have in developing innovative launch solutions. The biggest factor in deciding which launcher to develop is how much work it can provide to the ESA, member countries. This supersedes even lowered costs.

The ESA could develop a low cost launcher that would be comparable in cost to the SpaceX Falcon 9, AND moreover would give Europe an independent manned launch capability simply by adding a second Vulcain to the Ariane 5 core. Ironically though, this option is not chosen because it would be TOO low cost: it would be simple, quick - and not provide enough work to the ESA member countries.

The only way Europe is going to get low cost space access it now appears is if it is privately developed. As proven by SpaceX this can cut 90% (!) off the development costs. And in fact it should be even easier and cheaper than the SpaceX case since the components already exist in the Ariane 5 core, built in France, and Vulcain II engines, built in Germany. Even the capsule for the manned launchers is largely already designed in the Orbital Sciences, Cygnus capsule, which is actually built in Italy. You would just need to supply life support to the capsule already designed to be pressurized.

Bob Clark

 

[Urwumpe]

It is a common fallacy to look at the political bickering of ESA and claim that without these limits, all would be much better. It wouldn't currently, you pay what you want to get. ESA only coordinates efforts. If you would reduce that, you would need way more complex contracts and the politics will become worse, not better.

And can you please provide a hard number source for "90% less development costs for SpaceX"? The only one who claims so is Elon Musk, and even he does as usual not provide numbers. He does not even explain what reference the 100% are. NASA? Boeing? LMM? Sorry, but I am pretty allergic against repeating marketing slogans.

And the Vulcain II engine is build in France (and Sweden). Germany builds the upper stage engines, which have currently a much higher commercial potential.

 

[RGClark]

It is a common fallacy to look at the political bickering of ESA and claim that without these limits, all would be much better. It wouldn't currently, you pay what you want to get. ESA only coordinates efforts. If you would reduce that, you would need way more complex contracts and the politics will become worse, not better.

And can you please provide a hard number source for "90% less development costs for SpaceX"? The only one who claims so is Elon Musk, and even he does as usual not provide numbers. He does not even explain what reference the 100% are. NASA? Boeing? LMM? Sorry, but I am pretty allergic against repeating marketing slogans.

And the Vulcain II engine is build in France (and Sweden). Germany builds the upper stage engines, which have currently a much higher commercial potential.

The thrust chamber of the Vulcain is built in Ottobrunn, Germany:

Astrium Space Propulsion - Ottobrunn, Germany.
http://cs.astrium.eads.net/sp/home-otn.html

The source for the 90% cut in development cost of the commercial approach followed by SpaceX is NASA itself, which estimated the Falcon 9 cost 1/10th that of a comparable rocket under the traditional NASA costing models.
I discussed that in the first post in this thread, from a quote from an article in Aviation Week. That article is no longer available on the Av Week site, but I found it here:

SpaceX Might Be Able To Teach NASA A Lesson.

“I think one would want to understand in some detail . . . why would it be
between four and 10 times more expensive for NASA to do this, especially at a
time when one of the issues facing NASA is how to develop the heavy-lift launch
vehicle within the budget profile that the committee has given it,” Chyba
says.
He cites an analysis contained in NASA’s report to Congress on the market for
commercial crew and cargo services to LEO that found it would cost NASA between
$1.7 billion and $4 billion to do the same Falcon-9 development that cost SpaceX
$390 million. In its analysis, which contained no estimates for the future cost
of commercial transportation services to the International Space Station (ISS)
beyond those already under contract, NASA says it had “verified” those SpaceX
cost figures.
For comparison, agency experts used the NASA-Air Force Cost Model—“a
parametric cost-estimating tool with a historical database of over 130 NASA and
Air Force spaceflight hardware projects”—to generate estimates of what it would
cost the civil space agency to match the SpaceX accomplishment. Using the
“traditional NASA approach,” the agency analysts found the cost would be $4
billion. That would drop to $1.7 billion with different assumptions
representative of “a more commercial development approach,” NASA says.
http://aerospaceblog.wordpress.com/2011/05/24/spacex-might-be-able-to-teach-nasa-a-lesson/

The importance of this fact still is not properly appreciated. But I argue this will come to be regarded as the most important accomplishment of SpaceX, since it is the means by which spaceflight can become routine:

On the lasting importance of the SpaceX accomplishment.
http://exoscientist.blogspot.com/2012/06/on-lasting-importance-of-spacex.html

The only thing needed is European entrepreneurs with the insight, as Elon Musk in the U.S., to carry it out.


Bob Clark

 

[Urwumpe]

Sorry, but I don't think that this Elon-Musk-worship is rational. What has SpaceX really accomplished? It is just the Tesla Motors for SpaceFlight. Not the first, not the last, and not the most successful. Just one with the biggest marketing budget and a lot of fanboys. Pretty much the Apple of Spaceflight (But without the high profit margins by selling cheap hardware expensive). How much activity is at Tesla Motors now?

What is there to appreciate? His company would likely go the way of the dodo now, if it wouldn't be receiving tax payers money via NASA contracts. And in terms of reliability, the rockets have not really yet proven themselves. Yes, NASA projects cost more, because NASA considers more aspects. That is not because NASA is stupid. NASA has made some really bad experiences and has the scars to prove it. Currently SpaceX only launches cargo. No big loss if something goes wrong with the launcher. But once SpaceX starts to launch crew, the launch vehicle has to be reliable. And that not just by random flight-testing.

Just for putting things into perspective there: The Falcon 9 has almost the same number of publicly known anomalies than the Space Shuttle after the same number of flights. But NASA published all anomalies and not just those that had been impossible to hide. I don't really want to imagine how many glitches really exist behind each Falcon 9 launch. The real test of SpaceX has yet to come.

And quoting yourself for reference of your arguments is not really making this better(Exoscientist blog).

 

[RGClark]

Time will tell.

Bob Clark

 

[Urwumpe]

Time will tell.

Bob Clark

Exactly.

It leaves the question, if you could apply agile process management strategies from software development in the IT to spaceflight or hardware-heavy projects in general. Hardware does not really like refactoring, while software can tolerate it under limited circumstances.

As you can see in many other examples, it is always better to work with small steps, but you can also see that SpaceX skipped the small steps for the big goals and PR.

 

[RGClark]

Saw this mentioned on another forum:

30th January 2013, 16:45
New Ariane Europe cheap super rocket.

In seven years, Europe's new super rocket Ariane 6 stand for the first time. It is much cheaper than its predecessor - and probably bury the dream of your own human spaceflight By Gerhard Hegmann, Munich.

http://translate.google.com/transla...opas-billige-superrakete-1963368.html&act=url

Perhaps someone here can provide a better translation than Google.

Bob Clark

 

[MattBaker]

The introduction talks about how the Ariane 6 will be "much much cheaper" than the Ariane 5 and how this is going to bury manned spaceflight possibilities.
Then they give the numbers on the Ariane 5, 60% of all new contracts on communication satellites and how it was driven by technology in the 80s, while the Ariane 6 is now driven by money. Then there's this "triple-seven-concept", in 7 years, 7 mT payload and €70 million per launch.
Then they start with SpaceX and how fast new competitors can enter spaceflight and how SpaceX's prices (subsidised by NASA) are a big competition for Arianespace since contractors are interested in how much they pay [//which is wrong in my point of view, they also decide by reliability (otherwise Sea Launch would be...) and political stuff, why else is Astra etc launching Ariane?]. Lastly this paragraph talks about the Ariane 5 using €120 million per year on taxpayer's money and since Europe isn't that solvent like 30 years ago it's all about cost saving now.
Then they talk about the regional differences in the technology of the Ariane 6 with France and Italy building the solid stages while Germany is specialized on liquid ones and how instead of 6 or 7 double-launches by the A5 they're planning with a dozen of launches due to the one satellite per launch thing. Because of that they also make the maths about two satellites - €200 million and one satellite - €70 million while talking about SpaceX without even noticing that high production rates like 12/year could help drop the prizes too.
And then lastly they come up with manned launching stuff: Due to that cost saving strategy they're losing that possibility, while the A5 was developed with the idea of the Hermes spaceplane the A6 is developed with the idea of cheap launches. But they quickly end with that topic and rather talk about the A5 ME and how the R&D of the A6 will cost €4-5 billion, how it will be an expendable launch system that could render the Soyuz (which price is controlled by the Russians) from Korou unnecessary.
And in the end they talk about the political mills whose companies is going to build which parts of the rockets, something that should get decided in 2014.

 

[Urwumpe]

Well... not much new, a lot of sloppy journalism there, mostly based on the press conference of Le Gall. Who again boasted the French horn of "It would be cheaper producing the Ariane in one country". Of course, this would then also mean the rocket would have to become WAAAAY cheaper, because France can't afford such a high contribution to the ESA budget.

 

[RGClark]

...
And then lastly they come up with manned launching stuff: Due to that cost saving strategy they're losing that possibility, while the A5 was developed with the idea of the Hermes spaceplane the A6 is developed with the idea of cheap launches. But they quickly end with that topic and rather talk about the A5 ME and how the R&D of the A6 will cost €4-5 billion, how it will be an expendable launch system that could render the Soyuz (which price is controlled by the Russians) from Korou unnecessary...

The big point I took from the article is that the writer seems to be lamenting the demise of the dream of a European manned launch capability.

Bob Clark