Author Topic: VV at USOS  (Read 115832 times)

Offline Space Pete

Re: VV at USOS
« Reply #20 on: 05/28/2012 11:53 am »
With regard to when we might see two VVs at the USOS again:

According to anik's ISS schedule, SpX-1 (First CRS Dragon) is scheduled to berth to ISS on September 26 and unberth on October 26.

At the Dragon media briefing on Friday, Mike Suffredini said they are looking at mid-October for the Orb-D mission (first COTS Cygnus). So, we could potentially see a Dragon relo to Node 2 Zenith in mid October to allow Cygnus at Node 2 Nadir, with Cygnus leaving prior to Dragon going back to Node 2 Nadir.
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Offline manboy

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Re: VV at USOS
« Reply #21 on: 05/28/2012 01:15 pm »
Hmm, I wonder if the planned adapter rings will simplify multi-VV docking/berthing any... They need to make the USOS multi-VV friendly as is the current situation on the other end of the station (up to 4 VV with no problems on the RS). If not, the case is stronger for Node 4.
If you're talking about the two NDS-adapters then no...

I know it's probably too early to tell, but once SpaceX finishes the 12 contracted CRS flights, I wonder if they'll move to having a common vehicle with the crew flights. It would make more sense, and would actually "dock"...
But then you would need to launch more NDS-adapters to station or else the two will have to handle all the traffic from both crew and cargo missions.
« Last Edit: 05/28/2012 01:21 pm by manboy »
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Offline psloss

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Re: VV at USOS
« Reply #22 on: 05/28/2012 01:21 pm »
If VV traffic builds up, they will need Node 4.
Hence the Node 4 proposal.  If VV traffic doesn't build up, then they won't need it.

Offline PeterAlt

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Re: VV at USOS
« Reply #23 on: 05/28/2012 04:21 pm »
Maybe the rationale should be to launch it just in case. Better be safe than sorry. The ones controlling the purse strings should understand that logic.

Offline Jim

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Re: VV at USOS
« Reply #24 on: 05/28/2012 04:48 pm »
Maybe the rationale should be to launch it just in case. Better be safe than sorry. The ones controlling the purse strings should understand that logic.

Part of engineering is cost effectiveness and risk assessment.  There is no rationale to support launching.  There is no sorry and no need to be "safe".

Offline PeterAlt

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Re: VV at USOS
« Reply #25 on: 05/28/2012 05:05 pm »
Maybe the rationale should be to launch it just in case. Better be safe than sorry. The ones controlling the purse strings should understand that logic.

Part of engineering is cost effectiveness and risk assessment.  There is no rationale to support launching.  There is no sorry and no need to be "safe".

I spoke in very general terms. I meant it should be put into the next phase which is to assess the cost required to make the required engineering changes and improvements to it in order for it to function as a VV docking hub and to review launch options of cost of those options.

Offline PeterAlt

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Re: VV at USOS
« Reply #26 on: 05/28/2012 06:02 pm »
In theory, could Dragon, Cygnus, or HTV launch with Node 4 pre-attached (since all use CBM latches), use the carrying vehicle's thrusters and avionics to carry it to station and permanently berth Node 4?

The only limiting factor I see are weight restrictions...

Offline Space Pete

Re: VV at USOS
« Reply #27 on: 05/28/2012 06:06 pm »
The only limiting factor I see are weight restrictions...

And the fact that Node 4 will only have two radial CBM ports, meaning it would have to be launched off-axis, creating load and fairing issues.
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Offline Jorge

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Re: VV at USOS
« Reply #28 on: 05/28/2012 06:24 pm »
In theory, could Dragon, Cygnus, or HTV launch with Node 4 pre-attached (since all use CBM latches), use the carrying vehicle's thrusters and avionics to carry it to station and permanently berth Node 4?

The only limiting factor I see are weight restrictions...

Based on your parenthetical, I assume you mean the VV is launched with Node 4 berthed to the VV CBM. This is not possible for Dragon due to aerodynamics. The other two launch within fairings. Of course, weight is a show-stopper for all three. I doubt an F9 1.0 could even carry the node by itself, without the Dragon.
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Offline PeterAlt

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Re: VV at USOS
« Reply #29 on: 05/28/2012 06:38 pm »
The only limiting factor I see are weight restrictions...

And the fact that Node 4 will only have two radial CBM ports, meaning it would have to be launched off-axis, creating load and fairing issues.

Yuck... They could re-outfit the module, I suppose, but that will add to the overall cost in the form of additional eningeering and installation work, but that's still lower than the cost of starting over (I hope)!

Offline PeterAlt

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Re: VV at USOS
« Reply #30 on: 05/28/2012 06:41 pm »
In theory, could Dragon, Cygnus, or HTV launch with Node 4 pre-attached (since all use CBM latches), use the carrying vehicle's thrusters and avionics to carry it to station and permanently berth Node 4?

The only limiting factor I see are weight restrictions...

Based on your parenthetical, I assume you mean the VV is launched with Node 4 berthed to the VV CBM. This is not possible for Dragon due to aerodynamics. The other two launch within fairings. Of course, weight is a show-stopper for all three. I doubt an F9 1.0 could even carry the node by itself, without the Dragon.

Show stopper of HTV too? What if a F9-H launches the complex?

Offline Jorge

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Re: VV at USOS
« Reply #31 on: 05/28/2012 06:54 pm »
In theory, could Dragon, Cygnus, or HTV launch with Node 4 pre-attached (since all use CBM latches), use the carrying vehicle's thrusters and avionics to carry it to station and permanently berth Node 4?

The only limiting factor I see are weight restrictions...

Based on your parenthetical, I assume you mean the VV is launched with Node 4 berthed to the VV CBM. This is not possible for Dragon due to aerodynamics. The other two launch within fairings. Of course, weight is a show-stopper for all three. I doubt an F9 1.0 could even carry the node by itself, without the Dragon.

Show stopper of HTV too?

Yes. A stock H-IIB rocket cannot launch both a stock HTV and Node 4.

Quote
What if a F9-H launches the complex?

FH could handle the mass, but you would still not be able to launch it in the configuration you describe (Node 4 berthed to Dragon PCBM) because of aerodynamics (Node 4 would be on top in that config).

Might be possible to attach Node 4 to the trunk, but Dragon will have severe controllability issues due to the CG shift. Would likely have to place RCS thrusters on the aft end of Node 4 and run plumbing from Dragon through the node.

This has been discussed before, Peter. The most feasible configuration appears to be a Cygnus bus with Node 4 replacing the Cygnus PM. Additional RCS thrusters would still be required for contollability, and it would still be too heavy to launch on the Antares LV. Would need a heavy-class booster.
JRF

Offline PeterAlt

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Re: VV at USOS
« Reply #32 on: 05/28/2012 08:47 pm »
It looks like there's no simple solution to this, though its doable with some extra development work. That leaves traditional ELV rockets the only option left, but what will it use for transfer to the station? Is there anything "off th shelf" that will work with an ELV and Node 4 without the additional development cost, or are we left having to develop something no matter which lift is chosen? If so, what would be the least costly to develop of all lift options?

Offline Jim

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Re: VV at USOS
« Reply #33 on: 05/28/2012 08:53 pm »
It looks like there's no simple solution to this, though its doable with some extra development work. That leaves traditional ELV rockets the only option left, but what will it use for transfer to the station? Is there anything "off th shelf" that will work with an ELV and Node 4 without the additional development cost, or are we left having to develop something no matter which lift is chosen? If so, what would be the least costly to develop of all lift options?

A new ARD tug is needed.  This node 4 and tug and EELV has been discussed on many threads.  Look FTD.

Offline PeterAlt

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Re: VV at USOS
« Reply #34 on: 05/28/2012 09:08 pm »
It looks like there's no simple solution to this, though its doable with some extra development work. That leaves traditional ELV rockets the only option left, but what will it use for transfer to the station? Is there anything "off th shelf" that will work with an ELV and Node 4 without the additional development cost, or are we left having to develop something no matter which lift is chosen? If so, what would be the least costly to develop of all lift options?

A new ARD tug is needed.  This node 4 and tug and EELV has been discussed on many threads.  Look FTD.

Yes, I know it has. I did mention that that tug would need to be developed, without naming it. I'm trying to look at the bigger picture.

Offline Jim

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Re: VV at USOS
« Reply #35 on: 05/28/2012 09:25 pm »
It looks like there's no simple solution to this, though its doable with some extra development work. That leaves traditional ELV rockets the only option left, but what will it use for transfer to the station? Is there anything "off th shelf" that will work with an ELV and Node 4 without the additional development cost, or are we left having to develop something no matter which lift is chosen? If so, what would be the least costly to develop of all lift options?

A new ARD tug is needed.  This node 4 and tug and EELV has been discussed on many threads.  Look FTD.

Yes, I know it has. I did mention that that tug would need to be developed, without naming it. I'm trying to look at the bigger picture.

The bigger picture is that Node 4 is not required

Offline alexw

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Re: VV at USOS
« Reply #36 on: 05/28/2012 09:42 pm »
The most feasible configuration appears to be a Cygnus bus with Node 4 replacing the Cygnus PM. Additional RCS thrusters would still be required for contollability, and it would still be too heavy to launch on the Antares LV. Would need a heavy-class booster.
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Offline Jorge

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Re: VV at USOS
« Reply #37 on: 05/28/2012 09:43 pm »
The most feasible configuration appears to be a Cygnus bus with Node 4 replacing the Cygnus PM. Additional RCS thrusters would still be required for contollability, and it would still be too heavy to launch on the Antares LV. Would need a heavy-class booster.
    Do you consider AV552 to be a heavy-class booster?
                   -Alex

For this purpose, it's close enough, yes.
JRF

Offline woods170

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Re: VV at USOS
« Reply #38 on: 06/07/2012 02:29 pm »
Could be later this year with Dragon and Cygnus.

Could be never.

Who knows. :D
I think it will happen. Between HTV, Dragon and Cygnus that's what, 5-6 missions to USOS per year with each staying approx. 30 days? Eventually I think a mission will slip and maybe we'll be lucky enough to get a nice picture of both Cygnus and Dragon berthed during a Soyuz fly-around.

You're closer to what's planned for the coming years than you might imagine.
From the recent FPWG ISS flight plan (May 24th) I can see the following pattern for the 2013 to 2017 time-frame:

- 3 SpX flights each year - each will stay roughly 30 days at the station.
- 2 Orbital flights each year - each will stay rougly 30 days at the station.
- 1 HTV flight each year - it will stay roughly 30 days at the station.
- Those flights are all sequential. None of them run parallel, except SpX-3 and Orbital-2 in 2013.
- All of the above missions are planned to berth at Node-2 nadir, making for an interesting situation for SpX-3 and Orbital-2. Might require tempory re-location of SpX-3 to Node-2 zenith.
- Time between the departure of one vehicle from the station, to the launch of the next ranges from 5 days to 5 months.
- General sequence in a year: SpX - Orbital - SpX - HTV- SpX - Orbital.

With such a schedule, Node 4 is not required. Jim is right, as usual.
« Last Edit: 06/15/2012 06:22 am by woods170 »

Offline arkaska

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Re: VV at USOS
« Reply #39 on: 06/07/2012 04:14 pm »
The question is if it's worth spending the time relocation to zenith. Maybe that time could be spent unloading faster so the vehicle can undock earlier therefore saving the time it would take to relocate

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