Author Topic: Dream Chaser's European deal points to multi-role ambitions  (Read 34079 times)

Offline M129K

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #40 on: 01/09/2014 06:25 PM »

I find the idea that DC would be too heavy for Ariane V to be very bizarre.
As do I...

Too big =/= too heavy.

Lars and I were referring to this:
Quote from: Chris's article
before adding he thinks the Dream Chaser is currently a little bit too heavy for the launcher.
That's very odd indeed. I read past that sentence apparently. Very strange, considering Ariane 5 ME should be capable of lifting DC all the way to GTO if it was needed.

Offline Oli

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #41 on: 01/09/2014 07:39 PM »
Quote from: M129K
The Atlas first stage isn't a sustainer stage, and Centaur does a lot of the ∆V to reach orbit. The Ariane core almost reaches orbit and the ES upper stage only performs a small, 100-200 m/s burn on LEO flights. Are you sure DC isn't capable of that?

100-200 m/s? For a 20t payload a little calculation gives me 1228 m/s.

Offline M129K

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #42 on: 01/09/2014 07:56 PM »
Quote from: M129K
The Atlas first stage isn't a sustainer stage, and Centaur does a lot of the ∆V to reach orbit. The Ariane core almost reaches orbit and the ES upper stage only performs a small, 100-200 m/s burn on LEO flights. Are you sure DC isn't capable of that?

100-200 m/s? For a 20t payload a little calculation gives me 1228 m/s.
After rechecking myself, it gave me about 600 m/s. The EPS is short fueled for ATV missions to about 5 tons I believe. Anyway, this could very well be because ATV doesn't have the thrust to make a circ burn on it's own, forcing an upper stage to be used, and it only gives that much delta V because it is optimized with a ~5 ton prop load. DC doesn't have this thrust problem and doesn't have to require an upper stage for insertion, so it's possible the Ariane core does more of the burn to orbit. This would reduce payload of course, but if an Atlas V 402 can lift it into orbit, it shouldn't be that much of a problem.

Offline Jester

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #43 on: 01/09/2014 08:32 PM »
Ariane 5 is mass-limited to LEO because it's designed as a GTO launcher.
I don't know what the ME version will be able to carry but the ES version they currently use for ATV and which has structurally reinforced first stages is no longer around, it got discontinued long ago when they knew they're going to stop ATV.
That might be what they need to fix, they probably still know how to do it but it will come at a cost.

-ES is still around, Galileo will use it.

Offline pippin

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #44 on: 01/09/2014 08:32 PM »
With the reinforced core stage?

And can they still build them or are the ones for Galileo already built?
« Last Edit: 01/09/2014 08:33 PM by pippin »

Offline Rocket Science

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #45 on: 01/09/2014 08:55 PM »
Dream Chaser weighs about half about what Hermes was going to, 9-10,000kg vs 23,000kg FWIW...
« Last Edit: 01/10/2014 12:34 AM by Rocket Science »
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Offline Todd Martin

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #46 on: 01/09/2014 11:53 PM »
Great article; I've been starving for Dreamchaser news.  Like any good drama, we seem to be left with more questions than when we started.  Hopefully, we'll find out the contract value, the completion date, and the rationale behind DC using an ESA docking port.

Online Chris Bergin

Thanks Todd!

Also a correction, thanks to Yves and his better recording of the teleconference, per the "too heavy" reference:

>What he actually said is this: "[...]but I am only a civil engineer. I have to be very careful. Civil engineers are using concrete and this is a little bit too heavy for the launcher." See 55:20 of my recording (my recording may have been easier to understand than yours for this part). (Both recordings in L2).

In a nutshell,  Professor Woerner was joking by saying that a civil engineer would have used concrete but this is too heavy for the launcher (not DC). <

So that's a good result in the end. Corrected the article.

Offline Rocket Science

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #48 on: 01/10/2014 12:55 AM »
I found the mention of “education” as a factor interesting in their discussions...  8)
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Offline manboy

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #49 on: 01/10/2014 02:27 AM »
So, is this the resurrection of Hermes?

.. with similar capasity, much much lower mass. What I'm missing here?

Dreamchaser is something like 11 tonnes, hermes was getting too heavy for ariane V which could lift something like 20 tonnes. Both have similar class of capasity. How is dream chaser so much lighter?
It's smaller.
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Offline Elmar Moelzer

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #50 on: 01/10/2014 02:46 AM »
Thanks for the update, Chris!

Offline gosnold

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #51 on: 01/10/2014 08:51 AM »
Isn't ITAR going to be a problem for Europeans? For instance if they want to refurbish the craft themselves between launches?

Online yg1968

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #52 on: 01/10/2014 01:19 PM »
Isn't ITAR going to be a problem for Europeans? For instance if they want to refurbish the craft themselves between launches?

I am not an expert on ITAR but I don't think that SNC would sell a DC to ESA. They would rent it and SNC (or one of their U.S. subcontractors) would operate it. I believe that there are efforts to remove spacecrafts from ITAR. But that has yet to be done.
« Last Edit: 01/10/2014 01:35 PM by yg1968 »

Offline baldusi

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #53 on: 01/10/2014 01:35 PM »
So, is this the resurrection of Hermes?

.. with similar capasity, much much lower mass. What I'm missing here?

Dreamchaser is something like 11 tonnes, hermes was getting too heavy for ariane V which could lift something like 20 tonnes. Both have similar class of capasity. How is dream chaser so much lighter?
It's smaller.
That and the original Ariane V had less performance. An Ariane V could probably put 23tonnes to 25tonnes on LEO.

Offline woods170

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #54 on: 01/10/2014 01:48 PM »
So, is this the resurrection of Hermes?

.. with similar capasity, much much lower mass. What I'm missing here?

Dreamchaser is something like 11 tonnes, hermes was getting too heavy for ariane V which could lift something like 20 tonnes. Both have similar class of capasity. How is dream chaser so much lighter?
It's smaller.
That and the original Ariane V had less performance. An Ariane V could probably put 23tonnes to 25tonnes on LEO.

Please stop the discussion about DC being too heavy for Ariane 5. I refer to this post by Chris B. that clearly shows the full context of what was said: http://forum.nasaspaceflight.com/index.php?topic=33760.msg1145825#msg1145825

In short: it was never said that DC is too heavy for Ariane 5.

Offline gosnold

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #55 on: 01/10/2014 02:44 PM »
Isn't ITAR going to be a problem for Europeans? For instance if they want to refurbish the craft themselves between launches?

I am not an expert on ITAR but I don't think that SNC would sell a DC to ESA. They would rent it and SNC (or one of their U.S. subcontractors) would operate it. I believe that there are efforts to remove spacecrafts from ITAR. But that has yet to be done.

Well it would seem to go against the ESA "buy european" policy then. I was thinking DLR might buy a DC on its own funds (no political problems with ESA in this case) and then ESA could operate it with european industries doing the maintenance/refurbishment. But it is too early to tell anyway.

Offline Star One

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #56 on: 01/10/2014 04:04 PM »

Isn't ITAR going to be a problem for Europeans? For instance if they want to refurbish the craft themselves between launches?

I am not an expert on ITAR but I don't think that SNC would sell a DC to ESA. They would rent it and SNC (or one of their U.S. subcontractors) would operate it. I believe that there are efforts to remove spacecrafts from ITAR. But that has yet to be done.

Well it would seem to go against the ESA "buy european" policy then. I was thinking DLR might buy a DC on its own funds (no political problems with ESA in this case) and then ESA could operate it with european industries doing the maintenance/refurbishment. But it is too early to tell anyway.

I would have thought if they were going to buy it they would buy more than one?

Online yg1968

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #57 on: 01/10/2014 05:21 PM »
Isn't ITAR going to be a problem for Europeans? For instance if they want to refurbish the craft themselves between launches?

I am not an expert on ITAR but I don't think that SNC would sell a DC to ESA. They would rent it and SNC (or one of their U.S. subcontractors) would operate it. I believe that there are efforts to remove spacecrafts from ITAR. But that has yet to be done.

Well it would seem to go against the ESA "buy european" policy then. I was thinking DLR might buy a DC on its own funds (no political problems with ESA in this case) and then ESA could operate it with european industries doing the maintenance/refurbishment. But it is too early to tell anyway.

On the flip side, it would increase the production of Ariane 5ME rockets (which is a good thing for Germany/ESA).

But you may be right about DC4EU being a joint effort. See this press release by ESA:
http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station/Helping_make_Dream_Chaser_a_reality

Quote
At the end of an initial evaluation and planning phase, which will continue through 2014, the organisations expect to continue the relationship through a long-term agreement leading to flight operations. Both entities foresee further arrangements to continue the partnership towards the potential use of Dream Chaser for European missions.

See also this article:

Quote
Named DC4EU (Dream Chaser for European Utilization), the project is to explore ways in which the Dream Chaser®can be used to cover German and European requirements for the transportation of payloads and astronauts to the International Space Station (ISS) and for deployment as a manned or unmanned space vehicle allowing German and European scientists to conduct research under weightless conditions over extended periods of time.  Given the capability which the Dream Chaser® has for reaching orbits at a substantially greater altitude than the ISS, the study will determine the extent to which it is able to supply satellites or remove decommissioned satellites from their orbits.

http://www.4-traders.com/OHB-TECHNOLOGY-AG-450142/news/OHB-Technology-AG--Contract-signed-with-DLR-for-the-study-phase-for-the-utilization-of-US-company-17459911/
« Last Edit: 01/10/2014 05:41 PM by yg1968 »

Offline USFdon

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #58 on: 01/10/2014 05:36 PM »
Quote
Quote from: adrianwyard on Today at 03:45 PM

    I am not sure if ESA ever had in mind to upgrade their Soyuz launch facilities for ESA manned flights...


Wonder if the often talked about Soyuz-2-3 could lift a Dream Chaser to orbit from Kourou as an Ariane V is a bit too powerful for the job (unless you included cargo or something) . Now that would be an interesting development. Per Anatoly Zak, its pretty close at ~11-12 tons.

Edit: Better thread for this topic

Offline DT1

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Re: Dream Chaser's European deal points to multi-role ambitions
« Reply #59 on: 01/11/2014 09:46 AM »
Quote from: M129K
The Atlas first stage isn't a sustainer stage, and Centaur does a lot of the ∆V to reach orbit. The Ariane core almost reaches orbit and the ES upper stage only performs a small, 100-200 m/s burn on LEO flights. Are you sure DC isn't capable of that?

100-200 m/s? For a 20t payload a little calculation gives me 1228 m/s.
After rechecking myself, it gave me about 600 m/s. The EPS is short fueled for ATV missions to about 5 tons I believe. Anyway, this could very well be because ATV doesn't have the thrust to make a circ burn on it's own, forcing an upper stage to be used, and it only gives that much delta V because it is optimized with a ~5 ton prop load. DC doesn't have this thrust problem and doesn't have to require an upper stage for insertion, so it's possible the Ariane core does more of the burn to orbit. This would reduce payload of course, but if an Atlas V 402 can lift it into orbit, it shouldn't be that much of a problem.

I do not know the exact numbers of the delta v performed by the EPS of the Ariane 5ES (especially with the 2nd burn), but I remember that the very first presentation by ESA (approx. 15 years ago on an ILA Berlin Air Show) included no upper stage for the ATV flights to the ISS. The EPS was only added later. Maybe to keep more propellant for the ATV to reboost the station.
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