Author Topic: ESA Begins Work On Ariane 6  (Read 122353 times)

Offline mmeijeri

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Re: ESA Begins Work On Ariane 6
« Reply #20 on: 01/26/2010 08:16 pm »
It sounds as if the plan is to keep Ariane 5 flying until Ariane 6 is operational in 2025. Leaves plenty of time for ARV. And in a triple core configuration Ariane 6 could supposedly still carry ATV/ARV.
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Offline Serafeim

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Re: ESA Begins Work On Ariane 6
« Reply #21 on: 01/27/2010 01:34 pm »
http://www.flightglobal.com/articles/2010/01/19/337279/big-birds-and-high-flying.html

Quote
  The move to develop a single rocket capable of different missions is also perplexing for launcher experts. US National Air and Space Museum curator Roger Launius says: "The single rocket idea has never worked very well."

And ESA's launcher policy until now has been to create a family of launchers. It is still in the process of preparing to operate from French Guiana from 2011 the Ariane 5 for heavy spacecraft, the Italian-led Vega for small spacecraft and Russia's medium-class Soyuz.

Launius speculates that the 1,000kg gap mystery may be traced to unstated defence requirements - Dordain mentioned co-operation with the European Defence Agency at his press conference.

Tomorrow's Bird was to have been a two-year study finished by early 2008, but two years on ESA has released only executive summaries. Its implications for Europe's rockets mean, in retrospect, the study should probably have been called Tomorrow's Launcher.

I dont know if they will finally make that rocket...That modular style is the Angara style Russia knows more..maybe is best europe to stay with the Family launchers style

but if the future satellites are 10t ....Ariane 5 have this payload to geo..10t..why change it?
« Last Edit: 01/27/2010 01:36 pm by Serafeim »

Offline mmeijeri

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Re: ESA Begins Work On Ariane 6
« Reply #22 on: 01/27/2010 01:41 pm »
Very good question! It does seem inconsistent. William Barton, take note.
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Offline Analyst

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Re: ESA Begins Work On Ariane 6
« Reply #23 on: 01/27/2010 01:56 pm »
Looks like future GEO satellites won't be in the 10 metric tons class, but way below (3 to 7 metric tons).

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Offline William Barton

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Re: ESA Begins Work On Ariane 6
« Reply #24 on: 01/27/2010 02:19 pm »
I myself would hesitate to predict anything about future GEO satellites. There's accumulating evidence that comsats won't be part of that future.

Offline Analyst

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Re: ESA Begins Work On Ariane 6
« Reply #25 on: 01/27/2010 04:29 pm »
Care to share this evidence?

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Offline agman25

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Re: ESA Begins Work On Ariane 6
« Reply #26 on: 01/27/2010 04:43 pm »
I don't know if this counts as evidence but I stopped being a GSO comsat customer recently. Went from satellite to cable for my TV. Cable company gave me a bundled deal for both TV and internet.

TV and phone are moving to the internet and the internet is moving to the cloud. GSO comsats can't handle cloud computing due to signal latency issues. So long term they might be in trouble.

Offline William Barton

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Re: ESA Begins Work On Ariane 6
« Reply #27 on: 01/27/2010 04:54 pm »
Care to share this evidence?

Analyst

Quick to jump on my verbal excess! More like accumulating opinions, than "evidence." Other, cheaper technologies that might do the job as well or better. Expanding landline broadband networks for telecom, in particular. Even wireless broadband via cell towers. At some point, it may well be cheaper to finish up the ground network than keep on throwing up comsats. Then comsats will be a temporary bridge between the old cable network and the new one (kind of the way metal piston-engine planes were a bridge between biplanes and jets). At some point, comsats will reach their technological limits. Especially if they're forever limited by 25mT LVs.

A couple of other opinionoids, thrown in just for fun:

http://www.rand.org/pubs/technical_reports/TR234/index.html

http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/22398/1/97-0885.pdf

http://www.21stcenturyairships.com/HighAlt

I don't necessarily beliew the above will come to pass, just think it's interesting.

Offline William Barton

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Re: ESA Begins Work On Ariane 6
« Reply #28 on: 01/27/2010 04:59 pm »
I don't know if this counts as evidence but I stopped being a GSO comsat customer recently. Went from satellite to cable for my TV. Cable company gave me a bundled deal for both TV and internet.

TV and phone are moving to the internet and the internet is moving to the cloud. GSO comsats can't handle cloud computing due to signal latency issues. So long term they might be in trouble.

And that's part of the essense of my question about, What could you do with bigger GEO satellites? Suppose you had a comsat with enough bandwidth to talk directly to the electronics of a cell phone? How big an antenna would that take on the satellite? (The signal latency issue is separate from that.) I will shortly be moving to an area outside T1, cable and DSL reach, and since Hughes.net can't handle Vonage, I'll be back on a landline for phone service. (Actually, I'm probably going to go all-cellular, since there's a big tower on the horizon I can point a yagi aerial at.)
« Last Edit: 01/27/2010 05:08 pm by William Barton »

Offline Robotbeat

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Re: ESA Begins Work On Ariane 6
« Reply #29 on: 01/27/2010 05:07 pm »
The military/intelligence community would benefit from larger than 10 tons to GSO.
EDIT: Deleted my little off-topic shpeal.
« Last Edit: 01/27/2010 05:08 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline agman25

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Re: ESA Begins Work On Ariane 6
« Reply #30 on: 01/27/2010 05:49 pm »
I don't know if this counts as evidence but I stopped being a GSO comsat customer recently. Went from satellite to cable for my TV. Cable company gave me a bundled deal for both TV and internet.

TV and phone are moving to the internet and the internet is moving to the cloud. GSO comsats can't handle cloud computing due to signal latency issues. So long term they might be in trouble.

And that's part of the essense of my question about, What could you do with bigger GEO satellites? Suppose you had a comsat with enough bandwidth to talk directly to the electronics of a cell phone? How big an antenna would that take on the satellite? (The signal latency issue is separate from that.) I will shortly be moving to an area outside T1, cable and DSL reach, and since Hughes.net can't handle Vonage, I'll be back on a landline for phone service. (Actually, I'm probably going to go all-cellular, since there's a big tower on the horizon I can point a yagi aerial at.)
I found this
http://www.cellular-news.com/story/38544.php

Offline Serafeim

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Re: ESA Begins Work On Ariane 6
« Reply #31 on: 01/28/2010 02:33 pm »
http://www.flightglobal.com/blogs/hyperbola/2010/01/european-space-agency-planning.html#more

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  European Space Agency planning its own long-range "ESAS"

Offline mmeijeri

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Re: ESA Begins Work On Ariane 6
« Reply #32 on: 02/12/2010 11:52 am »
With hindsight, wouldn't it have been better for ESA to go from Ariane 4 to a kerolox version, with a three-core variant for heavy payloads? Now that Vulcain exists it may not be a good idea to throw it away and to convert Viking to kerolox. Does this mean Ariane 6 would be inferior to what it might have been had there not been an Ariane 5? Not saying this is the case, just wondering about people's opinions.
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Offline Archibald

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Han shot first and Gwynne Shotwell !

Offline woods170

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Re: ESA Begins Work On Ariane 6
« Reply #34 on: 02/13/2010 01:00 pm »
With hindsight, wouldn't it have been better for ESA to go from Ariane 4 to a kerolox version, with a three-core variant for heavy payloads? Now that Vulcain exists it may not be a good idea to throw it away and to convert Viking to kerolox. Does this mean Ariane 6 would be inferior to what it might have been had there not been an Ariane 5? Not saying this is the case, just wondering about people's opinions.
Why Kerolox? It translates into less energy per mass-unit of fuel. Agreed, Kerolox is a simpler technology but why would one convert Viking to Kerolox? That would translate into an entirely newly developed engine. Engine development is very expensive. I don't see the advantage of Kerolox over cryogenic.

Offline mmeijeri

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Re: ESA Begins Work On Ariane 6
« Reply #35 on: 02/13/2010 01:06 pm »
Why Kerolox? It translates into less energy per mass-unit of fuel. Agreed, Kerolox is a simpler technology but why would one convert Viking to Kerolox? That would translate into an entirely newly developed engine. Engine development is very expensive. I don't see the advantage of Kerolox over cryogenic.

For Ariane 5 they switched from a hypergolic Viking to a brand new cryogenic Vulcain and had to develop large SRBs too, although these had synergy with French nuclear missiles. The less drastic change of converting the Viking from toxic hypergolics to kerolox would have been an improvement. Conventional wisdom has it that kerolox is pretty close to optimal as a first stage propellant. The money spent developing Vulcain might have been better spent developing Vinci.

Again, I'm not saying this is true, just wondering.
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Offline woods170

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Re: ESA Begins Work On Ariane 6
« Reply #36 on: 02/13/2010 07:56 pm »
Why Kerolox? It translates into less energy per mass-unit of fuel. Agreed, Kerolox is a simpler technology but why would one convert Viking to Kerolox? That would translate into an entirely newly developed engine. Engine development is very expensive. I don't see the advantage of Kerolox over cryogenic.

Conventional wisdom has it that kerolox is pretty close to optimal as a first stage propellant. The money spent developing Vulcain might have been better spent developing Vinci.

That scenario still leaves me with no answer to the question: what engine would have run Kerolox? In your scenario that would not have been Vulcain, as it would not have been developed because the money would have been used on Vinci. And Viking does not run on Kerolox. Money diverted away from Vulcain to Vinci would create the issue of not having a Kerolox engine for the first stage. No engine, no launcher.

Also, suggesting that development money from Vulcain could have been diverted to Vinci is like comparing apples to pears. Vulcain is a first stage engine, producing roughly 1150 kN of vacuum thrust. Vinci is an upper stage engine, producing only 180 KN of vacuum thrust. Big difference.

The hypothetical switch from Viking (hypergolics) to "Engine-X" (Kerolox) still would have required the development of a completely new engine. To avoid the use of (environmentally polluting) solid boosters, "Engine-X" either would need to have been very large, or several of them should have been attached to the first stage.

Offline mmeijeri

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Re: ESA Begins Work On Ariane 6
« Reply #37 on: 02/13/2010 08:00 pm »
I was thinking converting Viking from hypergolic to kerolox would be a much smaller change than developing a brand new cryogenic engine. I believe such conversions have happened for US engines.
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Offline woods170

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Re: ESA Begins Work On Ariane 6
« Reply #38 on: 02/14/2010 12:49 pm »
I was thinking converting Viking from hypergolic to kerolox would be a much smaller change than developing a brand new cryogenic engine. I believe such conversions have happened for US engines.

Yeah, that could be done. But the primary payload for Ariane 5 was Hermes, big and heavy. You would have needed to strap a whole lot of converted Vikings together to get something with the lift capacity of the current Ariane 5 (that is, if one was not planning on using solid boosters). If solid boosters are still part of the story, then what is the use of converted Vikings? On the current Ariane 5 the solids basically ARE the first stage. Less than 10% of the thrust in the first 2 minutes comes from Vulcain. By the time the solids are dropped, most of the dense atmosphere is behind the launcher, and Kerolox is no longer the optimal solution for thrust. Cryogenic at that stage is the optimal solution, and it's also a lot more environmentally friendly than Kerolox, let alone hypergolic.

Offline mmeijeri

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Re: ESA Begins Work On Ariane 6
« Reply #39 on: 02/14/2010 12:57 pm »
Well, if you leave out Ariane 5 and just compare Ariane 4 to plans for Ariane 6, then it looks as if they are going back to a small core like Ariane 4, but now with a three core configuration for heavy payloads. The large solids are going away. If you forget about the propellant Ariane 6 looks closer to Ariane 4 than to Ariane 5. It would be interesting to know whether it is better to have three cryogenic cores like Delta IV Heavy or three kerolox cores like Atlas V Heavy. If the answer is kerolox, then Ariane 5 looks like a mistake in retrospect. Maybe even if you did intend to fly Hermes on it.
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