Author Topic: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)  (Read 1064575 times)

Offline Patchouli

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2000 on: 05/01/2018 09:39 pm »


Technically it should be easy, but it probably wouldn't be very useful. With fixed-position wings it can't fit in a fairing, meaning it can't carry the expendable module. Without that, pressurized volume drops by like half and it loses unpressurized capacity entirely, plus the scheduling benefit of being able to do IDS or CBM attachment. With the main launch options all being fully or mostly expendable, it seems difficult for such a craft to compete against the other CRS systems with such a drop in capability. It'd still need at least an AV N32 most likely, judging by the crew variant (less densely packed I assume) needing 2 boosters and 2 RL10s. Cygnus has over two times the pressurized volume, but requires no boosters and only 1 RL10 (~25-30 million dollars savings). And folding wings (even if deployed at liftoff, without a fairing) are likely a hard no for NASA crew missions
They would just go back to the original "fixed winglet" DC without a cargo module, an adapter plus abort engines for crewed flights or even back to the HL-20 adapter with SRMS for abort...
https://forum.nasaspaceflight.com/index.php?topic=29126.20
[/quote]

With New Glenn they probably can use SRMs for abort without any worries about it having an impact on payload.
Since it's stages are 7M wide the bending loads probably would be much less of an issue.
« Last Edit: 05/01/2018 09:41 pm by Patchouli »

Offline john smith 19

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2001 on: 05/07/2018 08:05 am »
A lot of people seem to be reading this as 'Sierra Nevada' owns the DC launched on the foreign rocket.  I, however, read this more as a 'sales ploy'. 

"So, ESA/JAXA wants its own astronaut launch capability?  Here, buy a couple DCs from us, they'll work on your launcher with just a little fine tuning." 

"Hey Virgin Galactic.  Why spend all that money developing SS-3 in-house when we have a perfectly viable system to put in your hands."
I think you have this backward.

SNC have a part of the CTS II contract.  It would make sense for them to investigate if other LV's can launch it cheaper than the current Atlas V baseline.

Obviously launching to the ISS is a nice reference mission for both Arianespace and (IIRC) Mitsubishi Heavy Industries to add to their portfolio for potential customers.

But AFAIK SNC would be buying those flights on their own. They would be the customer.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline brickmack

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2002 on: 06/03/2018 05:33 am »
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

Offline Star One

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2003 on: 06/03/2018 11:47 am »
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

You seem to be making a heck of a lot of assumptions here in multiple areas. For a start I very much doubt that Dragon offers a comparable downmass/volume capacity for the simple fact that DC is intending to fulfil its cargo commitments with less flights than Dragon is.

Offline SweetWater

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2004 on: 06/03/2018 12:57 pm »
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

We don't know how serious the interest in flying experiments on Dream Chaser is from any of these ~150 parties is - just that they have apparently expressed interest.

DragonLab got at least as far as SpaceX manifesting flights http://www.spacex.com/press/2012/12/19/spacex-adds-two-dragonlabtm-missions-manifest The press release is from December of 2008, about 18 months from when Falcon 9 first flew. I don't think they ever released who their customers were or why those flights were canceled.

Don't get me wrong - I'd like to see Dream Chaser succeed, and the interest alone is encouraging for Sierra Nevada. But right now there's just a tweet.

Offline yg1968

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2005 on: 06/03/2018 02:32 pm »
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

DC will only be using an Atlas V for its first flight. SNC has hinted that Blue Origin could be an option for its other flights to the ISS.

Online gongora

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2006 on: 06/03/2018 05:09 pm »
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

DC has one possible governmental organization sponsored cargo mission they're talking about.  That's not really much more success than DragonLab.

You seem to be making a heck of a lot of assumptions here in multiple areas. For a start I very much doubt that Dragon offers a comparable downmass/volume capacity for the simple fact that DC is intending to fulfil its cargo commitments with less flights than Dragon is.

DC can do fewer flights because it has a larger upmass volume, thanks to the expendable pressurized module they're using on the back of DC.

We don't know how serious the interest in flying experiments on Dream Chaser is from any of these ~150 parties is - just that they have apparently expressed interest.

DragonLab got at least as far as SpaceX manifesting flights http://www.spacex.com/press/2012/12/19/spacex-adds-two-dragonlabtm-missions-manifest The press release is from December of 2008, about 18 months from when Falcon 9 first flew. I don't think they ever released who their customers were or why those flights were canceled.

Don't get me wrong - I'd like to see Dream Chaser succeed, and the interest alone is encouraging for Sierra Nevada. But right now there's just a tweet.

There's no private sector interest in flying any of these vehicles at realistic mission prices.  I think you're making a bad assumption about SpaceX ever having customers for DragonLab.  I think they put notional missions on the manifest as advertising for the capability.

Offline rayleighscatter

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2007 on: 06/03/2018 08:46 pm »

There's no private sector interest in flying any of these vehicles at realistic mission prices.

Hit a big nail on the head there. It's no secret that the Russian half of ISS has much less science to do compared to the US half, mostly owing to funding. If there were good commercial demand for space science the Russians would be selling their excess capabilities, and much cheaper than any dedicated launch.

Offline deruch

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2008 on: 06/06/2018 07:12 pm »
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

I also think one of the big draws is that DC can be landed on a runway in other countries.  So, at least 1 participant country will get to have the vehicle landed in their territory.  That's a much more visible and higher profile demonstration of space activity for local consumption.  Additionally, maybe SNC just came up with a better business model?  IIRC, SpaceX was mainly trying to interest businesses or more individual research orgs.  By going through the UN, maybe SNC has gotten more interest.  The question will be how much money is there in that market?  Will funding be limited to a one-off?  Or will there be enough continuing interest, combined with available funding, to run multiple missions?
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Offline IW1DGG

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2009 on: 06/26/2018 10:17 am »
DC4EU
I found this interesting presentation available on internet about DC4EU on Ariane-6. It seems that ArianeGroup is seriously working on this.

http://www.essc.esf.org/fileadmin/user_upload/essc/2017-11-23_ESSC_Dream_Chaser_for_European_Utilisation.pdf

did you know that MPLMs, Node 2&3, Columbus Structure, ATV pressurized section and Cupola (50 % of the ISS), were built in Torino (Italy)?.... and now Axiom station, Gateway HALO structure, IHAB and ERM?

Offline Joseph Peterson

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2010 on: 07/13/2018 10:29 pm »
Article focused on Erin Ozmen.  I didn't notice anything new about Dream Chaser.  That said, I found it to be an interesting read.

https://www.forbes.com/sites/forbesdigitalcovers/2018/07/11/meet-the-unknown-immigrant-billionaire-betting-her-fortune-to-take-on-musk-in-space/

Offline TripleSeven

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2011 on: 07/13/2018 10:47 pm »


Hit a big nail on the head there. It's no secret that the Russian half of ISS has much less science to do compared to the US half, mostly owing to funding. If there were good commercial demand for space science the Russians would be selling their excess capabilities, and much cheaper than any dedicated launch.

you are in my view probably correct in that there is not a lot of....non government "commercial demand" for space science.

but I doubt really that even if there were the Russian segment would get the business. 

doing business with the Russians on their part of the space station is 1) very expensive and 2) very complicated in terms of dealing with the Russians.  plus, and this is being kind, the results on the Russian side are very well my words are "less rigorous" than what you get on the US/other side

micro gravity research is the great white whale of space flight...but at some point I predict the science and engineering with catch and harpoon this whale and someone is going to make some serious money with it

it wont be on the Russian side. 

Offline fast

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2012 on: 04/08/2019 07:29 am »
Why cargo module is conical and not cylindrical shape?

 

Offline b0objunior

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2013 on: 04/08/2019 07:42 am »
Why cargo module is conical and not cylindrical shape?

Larger base = more stable.

Offline ncb1397

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2014 on: 04/08/2019 07:45 am »
Why cargo module is conical and not cylindrical shape?

Larger base = more stable.

I think it would have more to do with the interface with the spaceplane has footprint limits while the cargo module has to maximize volume.

Offline b0objunior

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2015 on: 04/08/2019 07:47 am »
Why cargo module is conical and not cylindrical shape?

Larger base = more stable.

I think it would have more to do with the interface with the spaceplane has footprint limits while the cargo module has to maximize volume.
Also

Offline wings_no_capsules

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2016 on: 04/08/2019 07:37 pm »
hey...anyone got a pic of what the crewed DC would look like?

Also is the crewed variant dead? how long would it take to outfit a cargo DC for a crew?

Online Chris Bergin

Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2017 on: 04/08/2019 07:47 pm »
hey...anyone got a pic of what the crewed DC would look like?

Also is the crewed variant dead? how long would it take to outfit a cargo DC for a crew?

Welcome to the site's forum. I knew you'd be posting here when I saw the username :)

Crewed Dream Chaser is sort of dead. Some potential private deal, but it's dead to NASA and thus no real funding.

Looked like this:

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Online Prettz

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2018 on: 04/08/2019 08:32 pm »
So the black parts on the bottom and the wings are the heavy-duty heatshielding, while on the top, the white parts represent increased protection and the black is lighter protection?

Also, it looks like it has shoe treads on the bottom now.

Offline adrianwyard

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2019 on: 04/09/2019 06:57 pm »
Four years ago, shortly after Cargo Dream Chaser was revealed, we discussed how it appeared as if the aft thrusters would fire into the solar panels and/or other hardware.  The best guesses back then were that the graphics were inaccurate or the thrusters would not be used while attached to the cargo module, i.e. Dream Chaser would only fly backwards. (https://forum.nasaspaceflight.com/index.php?topic=37049.msg1347885#msg1347885).

But recent depictions (attached) seem to show the same problem. Furthermore, the aft pointing nozzles seem beefier than the others. So what's going on? Are the graphics and models still out of date? Or is it OK to plume the hardware behind you?

https://twitter.com/SierraNevCorp/status/1115637377299550208
https://twitter.com/SierraNevCorp/status/1115011424475127811






 

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