Author Topic: Orbital: Cygnus General Discussion Thread  (Read 70189 times)

Offline Billium

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Re: Orbital: Cygnus General Discussion Thread
« Reply #40 on: 11/02/2014 04:34 PM »
I was wondering if you could put the Pressurized Cargo Module (PCM) for Cygnus in the Dragon Trunk?

The PCM for Cygnus has a diameter of 3.07m and a height that looks to be about 2.4m. The dry mass is 1,500kg including the service module I think, so maybe just 750kg for the PCM?

Dragon has a diameter of 3.7m and CRS-8 is carrying BEAM in the trunk and BEAM has a 3.2m diameter (although this likely is less for transport) and 4m height and is 1,360kg.

It seems like it would fit to me. Thoughts?

Offline Jim

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Re: Orbital: Cygnus General Discussion Thread
« Reply #41 on: 11/02/2014 05:06 PM »
I was wondering if you could put the Pressurized Cargo Module (PCM) for Cygnus in the Dragon Trunk?

The PCM for Cygnus has a diameter of 3.07m and a height that looks to be about 2.4m. The dry mass is 1,500kg including the service module I think, so maybe just 750kg for the PCM?

Dragon has a diameter of 3.7m and CRS-8 is carrying BEAM in the trunk and BEAM has a 3.2m diameter (although this likely is less for transport) and 4m height and is 1,360kg.

It seems like it would fit to me. Thoughts?

No.

A.  the Dragon can not maneuver with it
b.  The PCM is not made to be pulled into orbit
c.  Trunk does not the structural capability
d.  No performance to carry it

Offline baldusi

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Re: Orbital: Cygnus General Discussion Thread
« Reply #42 on: 11/03/2014 01:30 PM »
I was wondering if you could put the Pressurized Cargo Module (PCM) for Cygnus in the Dragon Trunk?

The PCM for Cygnus has a diameter of 3.07m and a height that looks to be about 2.4m. The dry mass is 1,500kg including the service module I think, so maybe just 750kg for the PCM?

Dragon has a diameter of 3.7m and CRS-8 is carrying BEAM in the trunk and BEAM has a 3.2m diameter (although this likely is less for transport) and 4m height and is 1,360kg.

It seems like it would fit to me. Thoughts?

No.

A.  the Dragon can not maneuver with it
b.  The PCM is not made to be pulled into orbit
c.  Trunk does not the structural capability
d.  No performance to carry it
All that plus:
e. Trunk has radiators and solar panels. Cygnus has those on the service module.
f. would still need two adapters since Trunk is also the adapter to the F9 upper stage. And the smaller diameter of the Cygnus PCM would need to be attached to the wider Dragon base. And avoid damaging the heat shield at that.
g. If you look at the integrated Dragon, it has an attachment on the side from the Trunk to the capsule. It's usually called the Claw, but it routes power, heat rejection and data. You'd have to route that along the PCM.
h. It's easier to develop a PCM for Dragon than start from the Cygnus PCM. It's an idea I've proposed multiple times for CRS2.

Offline yg1968

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Re: Orbital: Cygnus General Discussion Thread
« Reply #43 on: 11/04/2014 08:18 PM »
Announcement tomorrow on going forward plans for Antares:
http://phx.corporate-ir.net/phoenix.zhtml?c=81036&p=irol-newsArticle&ID=1985588
« Last Edit: 11/04/2014 08:19 PM by yg1968 »

Offline Mader Levap

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Re: Orbital: Cygnus General Discussion Thread
« Reply #44 on: 11/27/2014 09:03 PM »
And no one is surpised in slighest. Except those folks that denied this possibility so vehemently...  ::)
Be successful.  Then tell the haters to (BLEEP) off. - deruch
...and if you have failure, tell it anyway.

Offline friendly3

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Re: Orbital: Cygnus General Discussion Thread
« Reply #45 on: 11/27/2014 11:06 PM »
Who are "those folks"?

Offline Mader Levap

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Re: Orbital: Cygnus General Discussion Thread
« Reply #46 on: 11/28/2014 01:39 PM »
Who are "those folks"?
Month ago or so (I do not remember exactly who, I just remember post) someone fumed at even mentioning possibility that Orbital would buy launch from SpaceX. After all, they are cutthroat competition, not in milion years or something.
Be successful.  Then tell the haters to (BLEEP) off. - deruch
...and if you have failure, tell it anyway.

Offline llanitedave

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Re: Orbital: Cygnus General Discussion Thread
« Reply #47 on: 11/28/2014 07:05 PM »
Who are "those folks"?
Month ago or so (I do not remember exactly who, I just remember post) someone fumed at even mentioning possibility that Orbital would buy launch from SpaceX. After all, they are cutthroat competition, not in milion years or something.

Yes, there is one who would insist that no choice is preferable to Atlas V.
"I've just abducted an alien -- now what?"

Offline TrevorMonty

Re: Orbital: Cygnus General Discussion Thread
« Reply #48 on: 11/28/2014 07:46 PM »
It would be interesting to know what SpaceX will charge Orbital. Last I read the Cygnus missions were costing NASA $200m+ each.
 Orbital might actually make a nice profit out of using the F9.

Offline friendly3

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Re: Orbital: Cygnus General Discussion Thread
« Reply #49 on: 11/29/2014 01:02 AM »
Who are "those folks"?
Month ago or so (I do not remember exactly who, I just remember post) someone fumed at even mentioning possibility that Orbital would buy launch from SpaceX. After all, they are cutthroat competition, not in milion years or something.

Well, they are no more "folks" but only "someone", that doesn't mean anything.
Orbital is a private old space company with some new space lipstick, they are mostly interested in $$$. So if they can make more $$$ by launching on Falcon 9 they will.
« Last Edit: 11/29/2014 01:09 AM by friendly3 »

Offline darkenfast

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Re: Orbital: Cygnus General Discussion Thread
« Reply #50 on: 11/29/2014 08:24 AM »
I see them as more complementary than competitive.  Cygnus and Dragon have different strengths and weaknesses.  SpaceX already works with Orbital on satellite launches.

Offline dror

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Re: Orbital: Cygnus General Discussion Thread
« Reply #51 on: 11/29/2014 10:32 AM »
(1)The standard sized Cyngus probably also can fit on Stratolaunch.
 OSC is developing the rocket so it would make sense to go ahead and design a payload interface for their own vehicles.

Not going to happen.

Can you please say why not?
Is (1) wrong or lack of performance or lack of incentives or short time scales or what?
"If we crave some cosmic purpose, then let us find ourselves a worthy goal. "
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Offline MP99

Re: Orbital: Cygnus General Discussion Thread
« Reply #52 on: 11/29/2014 03:53 PM »
I was wondering if you could put the Pressurized Cargo Module (PCM) for Cygnus in the Dragon Trunk?

The PCM for Cygnus has a diameter of 3.07m and a height that looks to be about 2.4m. The dry mass is 1,500kg including the service module I think, so maybe just 750kg for the PCM?

Dragon has a diameter of 3.7m and CRS-8 is carrying BEAM in the trunk and BEAM has a 3.2m diameter (although this likely is less for transport) and 4m height and is 1,360kg.

It seems like it would fit to me. Thoughts?

No.

A.  the Dragon can not maneuver with it
b.  The PCM is not made to be pulled into orbit
c.  Trunk does not the structural capability
d.  No performance to carry it

Re (d) - if F9 can really do 13t expendable to LEO, ISTM it could manage both a Dragon and a Cygnus (perhaps part loaded).

Not saying it would fit in the trunk or anything like that, but ISTM F9E has quite a lot of performance in reserve when it lifts Dragon.

Cheers, Martin

Offline guckyfan

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Re: Orbital: Cygnus General Discussion Thread
« Reply #53 on: 11/29/2014 04:41 PM »
Not saying it would fit in the trunk or anything like that, but ISTM F9E has quite a lot of performance in reserve when it lifts Dragon.

Cheers, Martin

The limitation would not be the payload capacity of Falcon 9 it would be the payload capacity of Dragon. According to wikipedia Dragon has a maximum payload of 3310kg. The dry mass of Cygnus would be included in this total mass.

Edited for clarity.
« Last Edit: 11/29/2014 04:42 PM by guckyfan »

Offline MP99

Re: Orbital: Cygnus General Discussion Thread
« Reply #54 on: 11/29/2014 06:05 PM »


Not saying it would fit in the trunk or anything like that, but ISTM F9E has quite a lot of performance in reserve when it lifts Dragon.

Cheers, Martin

The limitation would not be the payload capacity of Falcon 9 it would be the payload capacity of Dragon. According to wikipedia Dragon has a maximum payload of 3310kg. The dry mass of Cygnus would be included in this total mass.

Edited for clarity.

That appears to be a Dragon limitation, not an F9 one. I suspect the limitation is in total impulse and control authority of Dragon's thrusters.

Just a reminder, Dragon and Cygnus can't be linked. As you point out, Dragon can't possibly cope with the extra mass, and neither were designed to cope with being combined, anyway.

Assuming no payload in Dragon's trunk, any part of that 3310kg that won't fit in the pressurised volume becomes available to be part of Cygnus' mass.

If Cygnus launches underneath Dragon, it would be a completely independent secondary payload, just like that poor failed Orbcomm sat, or a CubeSat.

Given competition for the CBM, I suspect one of the pair would have to loiter while the other docks, is unloaded, reloaded and departs.

Dragon demonstrated some loiter capability on COTS 2/3, when it had to loiter after the "2" mission, before getting go to undertake the "3" mission. I believe Cygnus is quite capable of the same, if it comes to that.

Cheers, Martin

Offline mr. mark

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Re: Orbital: Cygnus General Discussion Thread
« Reply #55 on: 11/29/2014 06:24 PM »
Seems that this tread is heading in the wrong  direction. Sure, SpaceX might be launching Cygnus on a Falcon 9 but, this will be like any other independent CRS launch. They'll just put a fairing shroud around Cygnus and off she goes to put it simply. Of course, there are a lot of different elements to the launch but, it seems completely doable otherwise Orbital and SpaceX would not even entertain it.

Online AncientU

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Re: Orbital: Cygnus General Discussion Thread
« Reply #56 on: 11/30/2014 12:28 AM »
Wow, launch flexibility, responsiveness, lower prices, commercially viable launcher... sounds like something the USAF ought to look into... (Note: Orbital probably isn't paying a billion dollars a year to ensure such launch capability exists)
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Offline robertross

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Re: Orbital: Cygnus General Discussion Thread
« Reply #57 on: 11/30/2014 02:09 AM »
(1)The standard sized Cyngus probably also can fit on Stratolaunch.
 OSC is developing the rocket so it would make sense to go ahead and design a payload interface for their own vehicles.

Not going to happen.

Can you please say why not?
Is (1) wrong or lack of performance or lack of incentives or short time scales or what?


The timescale is just too far in the future.
Looking at how long White Knight took to develop and fly for VG, before you put a Cygnus on Stratolaunch vehicle it faces a similar test regime. Plus, the future is quite uncertain for the ISS (as per other threads).
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline MP99

Re: Orbital: Cygnus General Discussion Thread
« Reply #58 on: 11/30/2014 02:42 AM »
BTW, SpaceX lists Dragon as 6,000 kg (apparently including cargo, and including trunk cargo), and Billium lists Cygnus as 1,500 kg empty (which seems about right from my previous web searches).

Even if Dragon is at its max mass, then 2,500 kg of cargo in Cygnus would only bring the total mass to orbit up to 10t. If we're assuming 13t to std LEO, then I'd think that 10t would be possible to ISS inclination.

Not included in this mass is an adapter required to accommodate Cygnus under Dragon - it looks way too big to fit into the trunk.

However, I'm assuming Dragon's mass will be well under 6,000 kg as I wouldn't imagine it would carry any trunk cargo, so it appears to me the total mass to orbit would be well under 10t.

The biggest issue (and I think makes it completely impossible in the timeframe), is having to develop the  adapter / trunk extension to physically accommodate Cygnus. This would also, of course change the relationship of Dragon to the TEL (total height of the stack).

Cheers, Martin

Offline Billium

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Re: Orbital: Cygnus General Discussion Thread
« Reply #59 on: 11/30/2014 03:49 AM »
Thanks to Jim and everyone who replied to my post. I think my problem is lack of solid information on the hight and mass of the PCM of cygnus and the dimensions of what will fit in the dragon trunk.

The sources I can find indicate cygnus is 3.66m high and 1,500kg for the whole thing. Does anyone know how much just for the PCM? Assuming both dry, which would have more mass, the PCM or SM?

If dragon can carry 3,300kg total, and carries 1,500kg of its own pressurized cargo, that leave 1,800kg for the trunk. If the PCM alone is 800kg that leaves 1,000kg for PCM cargo. I don't know the mass of the PCM, but it looks like mass is not a problem. As I say I would be very interested in better information.

In term of height I estimated PCM at 2.4m, because the extended cygnus adds 1 segment and 1.2m, the normal cyguns is made up of 2 segments.

Beam is going in the trunk for CRS-8, and it is 4m tall, so the PCM should be smaller. So is the problem diameter? Beam is supposed to be 3.2m, and Cygnus is 3.07m, but maybe that is the inflated diameter of beam, not what travels in the trunk.

I was thinking the Canada arm could just pull PCM out of the trunk after berthing.

Anyways, I'm happy to be wrong, but I don't understand what the wrong assumptions are that I have made. If anyone can provide more details on what is wrong with my calculations I would appreciate it.

As an aside, Dragon is volume constrained, maybe Spacex could add their own PCM to the trunk for the next contract. It would have to be disposable, which isn't there style, but it could significantly add to their pressurized volume.


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