Author Topic: Orbital: Cygnus General Discussion Thread  (Read 71163 times)

Offline edkyle99

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Re: Orbital: Cygnus General Discussion Thread
« Reply #60 on: 11/30/2014 05:01 am »
Re (d) - if F9 can really do 13t expendable to LEO, ISTM it could manage both a Dragon and a Cygnus (perhaps part loaded).
SpaceX listed 13.15 tonnes payload to a 185 km x 28.5 deg orbit.  That only means 12 point something tonnes (maybe 12.3 tonnes, give or take) to a 51.6 deg ISS orbit, still at only 185 km.

The most recent Dragons were more than 8.6 tonnes loaded, and the blown up Cygnus was something like 5.6 tonnes loaded.

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Offline friendly3

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Re: Orbital: Cygnus General Discussion Thread
« Reply #61 on: 11/30/2014 06:50 am »
-Falcon 9 fairing : 13.1m height, 5.2m diameter
-"Old Cygnus" : 5.1m height, 3.07m diameter
-Enhanced Cygnus : 6.36m height, 3.07m diameter

No way to put a Cygnus inside Dragon's trunk. Fig 4, 5 and 6 won't happen.
The maximum payload of an enhanced Cygnus on an Antares was supposed to be 2,700 kilograms. Of course it will be much more on a Falcon 9.

Offline MP99

Re: Orbital: Cygnus General Discussion Thread
« Reply #62 on: 11/30/2014 07:47 am »


Re (d) - if F9 can really do 13t expendable to LEO, ISTM it could manage both a Dragon and a Cygnus (perhaps part loaded).
SpaceX listed 13.15 tonnes payload to a 185 km x 28.5 deg orbit.  That only means 12 point something tonnes (maybe 12.3 tonnes, give or take) to a 51.6 deg ISS orbit, still at only 185 km.

The most recent Dragons were more than 8.6 tonnes loaded, and the blown up Cygnus was something like 5.6 tonnes loaded.

 - Ed Kyle


Thanks for setting me straight, Ed.

Looks like this is where I was going wrong:-

BTW, SpaceX lists Dragon as 6,000 kg (apparently including cargo, and including trunk cargo)...

Guess that's empty, then.

Didn't appreciate that there was such a difference in the mass efficiency of Cygnus dry mass vs Dragon.

Cheers, Martin

Offline newpylong

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Re: Orbital: Cygnus General Discussion Thread
« Reply #63 on: 11/30/2014 11:07 am »
You are all assuming this launch is going to be from the East Coast and thus the full payload capability of F9 will be available.

Does their near term manifest allow for an East Coast launch, or is the "hole" in the manifest just SLC-4? Should be plenty of performance for Cygnus vs Dragon off the West Coast.

Online guckyfan

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Re: Orbital: Cygnus General Discussion Thread
« Reply #64 on: 11/30/2014 11:40 am »
You are all assuming this launch is going to be from the East Coast and thus the full payload capability of F9 will be available.

Does their near term manifest allow for an East Coast launch, or is the "hole" in the manifest just SLC-4? Should be plenty of performance for Cygnus vs Dragon off the West Coast.

West coast depends on NASA being able to load Cygnus there, especially late load. Do we know they can do it in Vandenberg?

Offline Prober

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Re: Orbital: Cygnus General Discussion Thread
« Reply #65 on: 11/30/2014 12:09 pm »
You are all assuming this launch is going to be from the East Coast and thus the full payload capability of F9 will be available.

Does their near term manifest allow for an East Coast launch, or is the "hole" in the manifest just SLC-4? Should be plenty of performance for Cygnus vs Dragon off the West Coast.

West coast depends on NASA being able to load Cygnus there, especially late load. Do we know they can do it in Vandenberg?

Late loads for Cygnus were processed horizontally the same as Dragon.  Flying loads out west shouldn't be an issue.  Dragon science return is handled from out west.
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Offline Jim

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Re: Orbital: Cygnus General Discussion Thread
« Reply #66 on: 11/30/2014 03:24 pm »

Late loads for Cygnus were processed horizontally the same as Dragon.  Flying loads out west shouldn't be an issue.  Dragon science return is handled from out west.


Not the same.  Cygnus is in a fairing, where as Dragon is not.  There is no access to the Cygnus while in the fairing.  Dragon can be accessed at the pad.   Location of science return has no bearing on prelaunch early access

Offline Prober

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Re: Orbital: Cygnus General Discussion Thread
« Reply #67 on: 11/30/2014 04:50 pm »

Late loads for Cygnus were processed horizontally the same as Dragon.  Flying loads out west shouldn't be an issue.  Dragon science return is handled from out west.


Not the same.  Cygnus is in a fairing, where as Dragon is not.  There is no access to the Cygnus while in the fairing.  Dragon can be accessed at the pad.   Location of science return has no bearing on prelaunch early access

huh? you saying Cygnus didn't do late loading?

again flying late loads out to the West coast vs East coast should NOT be and issue.
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Offline newpylong

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Re: Orbital: Cygnus General Discussion Thread
« Reply #68 on: 12/01/2014 06:33 pm »

Late loads for Cygnus were processed horizontally the same as Dragon.  Flying loads out west shouldn't be an issue.  Dragon science return is handled from out west.


Not the same.  Cygnus is in a fairing, where as Dragon is not.  There is no access to the Cygnus while in the fairing.  Dragon can be accessed at the pad.   Location of science return has no bearing on prelaunch early access

huh? you saying Cygnus didn't do late loading?

again flying late loads out to the West coast vs East coast should NOT be and issue.

No you are correct, they will be able to have the same access on the West or East coast. I think he was just saying Cygnus can't be accessed on the pad like Dragon can - not that there physically is even a way for a human to get access to Dragon once vertical. If it has to come down  be accessed it might as well be the same as rolling back and pulling the fairing like Cygnus. ULA really is the only one with true pad access.
« Last Edit: 12/01/2014 06:34 pm by newpylong »

Offline baldusi

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Re: Orbital: Cygnus General Discussion Thread
« Reply #69 on: 12/01/2014 07:19 pm »

Late loads for Cygnus were processed horizontally the same as Dragon.  Flying loads out west shouldn't be an issue.  Dragon science return is handled from out west.


Not the same.  Cygnus is in a fairing, where as Dragon is not.  There is no access to the Cygnus while in the fairing.  Dragon can be accessed at the pad.   Location of science return has no bearing on prelaunch early access

huh? you saying Cygnus didn't do late loading?

again flying late loads out to the West coast vs East coast should NOT be and issue.
SpaceX has demonstrated something like L-8hr late load, by using a special "clean room" tent on the TE, at the pad. For Cygnus, I believe that Late Load is something like L-48hr (before transport to pad), in the HIF. So "late load" doesn't means the same.

Offline Jim

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Re: Orbital: Cygnus General Discussion Thread
« Reply #70 on: 12/01/2014 08:13 pm »

again flying late loads out to the West coast vs East coast should NOT be and issue.


It isn't flying them out.  It is having a lab available at the launch site to prep the payloads.

Offline pericynthion

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Re: Orbital: Cygnus General Discussion Thread
« Reply #71 on: 12/02/2014 12:57 am »
I was curious what the record was for the minimum inclination (most easterly azimuth) launch from Vandenberg. From trawling Jonathan McDowell's launch log and the Space Track database, best I can find was NROL-3, with a 57 degree inclination.  I think that requires a dogleg to avoid Baja; an ISS launch would need a larger dogleg.  I haven't run the numbers to see the impact on payload performance for an F9.

Online TrevorMonty

Re: Orbital: Cygnus General Discussion Thread
« Reply #72 on: 12/03/2014 08:29 am »
SpaceFlight Insider has received word that the potential prime “contender” to ferry Orbital Sciences Corporation’s Cygnus spacecraft to orbit, and thus allow Orbital to complete its requirements under the $1.9 billion Commercial Resupply Services (CRS ) contract – is none other than fellow CRS participant – SpaceX. If this turns out to be true, it would mean that both current CRS firms – would be flying on the same rocket.
Source: spaceflightinsider.com

What surprises me the most about this information is that SpaceX can make two F9s available within a year (expected launch dates mid - late 2015) of being ordered. The industry norm is 2 years. With the RLV SpaceX could have lead times in months even weeks if customers are willing to use a 2nd hand booster. The other plus for customers is the option to launch earlier if their satellite is ready, complete satellites don't make any money sitting on ground waiting on LVs. To compete competitors may need to have spare LVs.

Online Zed_Noir

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Re: Orbital: Cygnus General Discussion Thread
« Reply #73 on: 12/03/2014 11:16 am »
SpaceFlight Insider has received word that the potential prime “contender” to ferry Orbital Sciences Corporation’s Cygnus spacecraft to orbit, and thus allow Orbital to complete its requirements under the $1.9 billion Commercial Resupply Services (CRS ) contract – is none other than fellow CRS participant – SpaceX. If this turns out to be true, it would mean that both current CRS firms – would be flying on the same rocket.
Source: spaceflightinsider.com

What surprises me the most about this information is that SpaceX can make two F9s available within a year (expected launch dates mid - late 2015) of being ordered. The industry norm is 2 years. With the RLV SpaceX could have lead times in months even weeks if customers are willing to use a 2nd hand booster. The other plus for customers is the option to launch earlier if their satellite is ready, complete satellites don't make any money sitting on ground waiting on LVs. To compete competitors may need to have spare LVs.
IIRC According to Jim LVs are build to order to the payload. So having  a number of spare cores might not work.

Of course SpaceX have the advantage of being able to modifying a LV stack on the fly since they have very few supply chain bottlenecks. Most parts are just on the other side of the SpaceX factory instead of on other side of the country.

Online rpapo

Re: Orbital: Cygnus General Discussion Thread
« Reply #74 on: 12/03/2014 11:26 am »
IIRC According to Jim LVs are build to order to the payload. So having  a number of spare cores might not work.

Of course SpaceX have the advantage of being able to modifying a LV stack on the fly since they have very few supply chain bottlenecks. Most parts are just on the other side of the SpaceX factory instead of on other side of the country.
The only physical part of the Falcon that should need customization is the spot where the satellite mounts to the rocket.  I wouldn't characterize that as making a custom launch vehicle, though.  Witness the core swap between AsiaSat 6 and CRS-4, for instance.  If the rockets were truly custom, that would not have been easy.

The flight software (or some data tables therein) would need to be updated, though I suspect that is an extreme "late load" item...

Jim may know better, as he gets to see the hardware firsthand.
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Offline kevin-rf

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Re: Orbital: Cygnus General Discussion Thread
« Reply #75 on: 12/03/2014 02:41 pm »
IIRC According to Jim LVs are build to order to the payload. So having  a number of spare cores might not work.
Of course Jim has pointed out in the distance pre ULA past that Lockheed use to keep an extra Atlas in the flow so they could quickly accommodate opportunities like this. For some reason I suspect ULA no longer does this.
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Offline baldusi

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Re: Orbital: Cygnus General Discussion Thread
« Reply #76 on: 12/03/2014 06:27 pm »

It's not a two in one year. Orbital expects about two years for the 200 Antares. So it might be closer to one core in 15 months and one core in 20 months. Besides, when you have a busy manifest and you are planning 12+ cores equal cores per year, you can do some tricks.
Let's say for the sake of example that you have a 24months production schedule. But you are producing 12 cores per year (or one per month). And your pipeline is separated in 12 steps, so you have two cores in each stage of the pipepline, 24 total. It's not like this but is just to get an example.
So, you normally set the schedule for each stage of the production pipeline with some margin. You can't really accelerate a 24month production schedule to 12months. But if you can shave 1 week from each stage if you work overtime and accelerate some processes. Suddenly the core that was L-4months can be pushed to L-3. Since you can now build a whole core in 18months, you keep pushing cores ahead of schedule and can thus offer an L-15months contract since the actual payload for that contract (the one that was L-18 now), will get the core that could rush to build in 18 months.
In reality, the shift is not that extreme but can be done. Of course that this works fine when you have 10+ rockets per year in production. For Delta IV like productions it doesn't works (the fact that the engines require L-30 lead time because of the ablative nozzle construction, doesn't help).
« Last Edit: 12/08/2014 01:29 pm by Chris Bergin »

Offline 411rocket

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Re: Orbital: Cygnus General Discussion Thread
« Reply #77 on: 12/04/2014 04:52 am »
Also remember, 39A could be available, to use around then. So potentially, all ISS flights could be launching from 39A, while commercial continues at LC40. That is, until Brownsville is ready, for operations.
« Last Edit: 12/08/2014 01:29 pm by Chris Bergin »

Offline rayleighscatter

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Re: Orbital: Cygnus General Discussion Thread
« Reply #78 on: 12/06/2014 11:28 pm »
It's not a two in one year. Orbital expects about two years for the 200 Antares.
I picked up somewhere that Orbital expects a hotfire at the end of 2015. I can't recall where though, so feel free to call bunk on it.

Offline arachnitect

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Re: Orbital: Cygnus General Discussion Thread
« Reply #79 on: 12/06/2014 11:58 pm »
It's not a two in one year. Orbital expects about two years for the 200 Antares.
I picked up somewhere that Orbital expects a hotfire at the end of 2015. I can't recall where though, so feel free to call bunk on it.

I saw something similar in USA Today.

Late 2015 hotfire, 2016 launch. Also doing soil (sand?) remediation at the crash site.

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