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.
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"...
If VV traffic builds up, they will need Node 4.
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.
Quote from: PeterAlt on 05/28/2012 04:21 pmMaybe 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".
The only limiting factor I see are weight restrictions...
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...
Quote from: PeterAlt on 05/28/2012 06:02 pmThe 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.
Quote from: PeterAlt on 05/28/2012 06:02 pmIn 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.
Quote from: Jorge on 05/28/2012 06:24 pmQuote from: PeterAlt on 05/28/2012 06:02 pmIn 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?
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?
Quote from: PeterAlt on 05/28/2012 08:47 pmIt 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.
Quote from: Jim on 05/28/2012 08:53 pmQuote from: PeterAlt on 05/28/2012 08:47 pmIt 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 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.
Quote from: Jorge on 05/28/2012 06:54 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
Quote from: Space Pete on 05/25/2012 09:52 pmCould be later this year with Dragon and Cygnus.Could be never.Who knows. 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.
Could be later this year with Dragon and Cygnus.Could be never.Who knows.