Cygnus bus with an MPLM attached launched on an EELV?

[Robotbeat]

Would it be possible to use a Cygnus bus with a larger MPLM-like pressure vessel and launch the whole thing on an EELV for post-Shuttle ISS logistics? I.e. how easy (or hard) would it be for Cygnus to be scaled up?

The Cygnus bus is about 1800kg, the existing pressure vessel part is around 3500kg (I think that's with 2000-2700kg included?).

Is the Cygnus bus being seriously considered for use as the Automated Rendezvous and Docking Vehicle (ARDV)?

An MPLM can fit just over 9000kg of cargo in it (mass of ~13200kg full), over three times the Cygnus's (enhanced) 2700kg, plus an MPLM can carry full racks.

It should all fit on an Atlas V 541 or something less.

(BTW, I think this should probably be in the Orbital section. Sorry!)

[sdsds]

Would it be possible to use a Cygnus bus with a larger MPLM-like pressure vessel and launch the whole thing on an EELV for post-Shuttle ISS logistics?

That seems like a really logical kind of lego spacecraft.  (As a name for it, what kind of bird is similar to but bigger than a swan?)

Is the Cygnus bus being seriously considered for use as the Automated Rendezvous and Docking Vehicle (ARDV)?

ARDV was one of the Flagship Technology Demonstration "point of departure" designs.  The conclusion of the FTD activity was to create the Technology Roadmaps. 
http://www.nasa.gov/offices/oct/home/roadmaps/index.html

In particular, second 2.1.6 of the Technology Area 4 Roadmap, (Robotics, Tele-Robotics and Autonomous Systems) is about AR&D.
http://www.nasa.gov/pdf/501622main_TA04-Robotics-DRAFT-Nov2010-A.pdf

The external (to NASA) review of the roadmaps led to the March, 2011 Broad Agency Announcement soliciting Technology Demonstration Missions.  TDM proposals are due May 31, 2011.
http://www.nasa.gov/offices/oct/crosscutting_capability/tech_demos/tdm_solicitations.html

Are there any indications Orbital will submit an ARDV-like proposal?

[Patchouli]

Probably not directly you'd need more fuel but I don't see why something could not be derived from the Cygnus propulsion system for it.

As for a name I'd just call it Cygnus XL or similar.

[Jim]

There is little work going on with ARDV as far as NASA goes.  The TDM werent in the budget

[Danderman]

There is little work going on with ARDV as far as NASA goes.  The TDM werent in the budget

What about that Node 4 tug proposal?


Anyway, getting back to the question posed at the top, I doubt whether the Cygnus design can provide sufficient control authority with an MPLM on the nose to safely approach ISS.

[Robotbeat]

There is little work going on with ARDV as far as NASA goes.  The TDM werent in the budget

What about that Node 4 tug proposal?


Anyway, getting back to the question posed at the top, I doubt whether the Cygnus design can provide sufficient control authority with an MPLM on the nose to safely approach ISS.

I certainly would think there would need to be some modifications to the Cygnus bus (possibly more powerful thrusters, reinforced structure, more fuel), but generally it'd be the same.

BTW, a question to those who've actually done satellite work:
What drives the design? What margins on control authority are needed, and what are the trade-offs for less thrust?

For other satellites, low-thrust ion thrusters (or other electric thrusters) can be used for station keeping, so it's not a 100% given that the thrusters wouldn't have enough control authority just as is (we'd need to know the specifics to be able to say that with any certainty).

[Sparky]

I note that you do say "MPLM-like" modules, but 1) there are only 2 MPLMs on Earth right now, and 2) what would be the cost of building more?

[Robotbeat]

I note that you do say "MPLM-like" modules, but 1) there are only 2 MPLMs on Earth right now, and 2) what would be the cost of building more?

Note that Cygnus's pressurized section is essentially a scaled-down MPLM, built by the same folks as built the MPLMs. I'd imagine it would be proportionally more expensive (~3x), maybe less (depending on how many you ordered).

[sdsds]

I note that you do say "MPLM-like" modules, but 1) there are only 2 MPLMs on Earth right now, and 2) what would be the cost of building more?

Note that Cygnus's pressurized section is essentially a scaled-down MPLM, built by the same folks as built the MPLMs.

* Under contract with Orbital for the Cygnus Pressurized Cargo Modules
* Prime contractor for MPLM and for PMM.
* Prime contractor for Node 2, Node 3, and Cupola. 
* Major contributor to Columbus. 
* Major contractor for the ATV cargo carrier section. 

In total, they have contributed to more than 50% of ISS pressurized volume.

http://www.thalesaleniaspace-issmodules.com/

I'd imagine it would be proportionally more expensive (~3x), maybe less (depending on how many you ordered).

I think it's fair to say that for a customer that can provide sufficient incentive, Thales Alenia Space has the tooling and the experienced personnel needed to start construction quickly and deliver product that would work.

I personally don't think a customer exists for this application, because I don't forsee a shortfall of ISS pressurized up-mass.

[butters]

I imagine that the most costly items are the avionics: power, computing, software, comms, navigation, and cooling. If they can keep that more or less in common with Cygnus (or ATV, HTV, Dragon...) then scaling up the propulsion and structures shouldn't be the most prohibitive thing in the world.

[Robotbeat]

I imagine that the most costly items are the avionics: power, computing, software, comms, navigation, and cooling. If they can keep that more or less in common with Cygnus (or ATV, HTV, Dragon...) then scaling up the propulsion and structures shouldn't be the most prohibitive thing in the world.

Precisely. I'd imagine that it'd cost less per-pound than the existing Cygnus bus.

[Patchouli]

I imagine that the most costly items are the avionics: power, computing, software, comms, navigation, and cooling. If they can keep that more or less in common with Cygnus (or ATV, HTV, Dragon...) then scaling up the propulsion and structures shouldn't be the most prohibitive thing in the world.

The upgraded Cygnus would be a logical addition to the upgraded Taurus II with a high energy upper stage.

[Robotbeat]

I imagine that the most costly items are the avionics: power, computing, software, comms, navigation, and cooling. If they can keep that more or less in common with Cygnus (or ATV, HTV, Dragon...) then scaling up the propulsion and structures shouldn't be the most prohibitive thing in the world.

The upgraded Cygnus would be a logical addition to the upgraded Taurus II with a high energy upper stage.

Cygnus is already being upgraded for the HEUS. The first three Cygni (including the one COTS demo Cygnus) will have less volume and payload capability than the last six (2000kg versus 2700kg).

[RocketmanUS]

So how long can Cygnus stay in orbit ( not the propulsion bus )?

Can it be turned into an PMM similar to Leonardo?

[manboy]

I note that you do say "MPLM-like" modules, but 1) there are only 2 MPLMs on Earth right now, and 2) what would be the cost of building more?

Note that Cygnus's pressurized section is essentially a scaled-down MPLM, built by the same folks as built the MPLMs. I'd imagine it would be proportionally more expensive (~3x), maybe less (depending on how many you ordered).

Why not launch a shortened node module or better yet a smaller diameter node module (that could be launched on Antares) based on the Cygnus PCM. ESA could possibly pay for some of the costs for the pressurized section since they still owe NASA.

[manboy]

And here's my node concept attached to the ISS, I was too lazy to draw PMA-2 but it would be attached to the forward CBM. You would probably only be able to use two of the axial ports at a time but this concepts frees up the CBMs on Harmony nadir and zenith.

[Space Pete]

And here's my node concept attached to the ISS, I was too lazy to draw PMA-2 but it would be attached to the forward CBM. You would probably only be able to use two of the axial ports at a time but this concepts frees up the CBMs on Harmony nadir and zenith.

Do you mean that it would be attached to PMA-2 via APAS, or attached to the forward CBM of Node 2 - in which case PMA-2 would have to be moved (possibly to the forward port of your Node)?

This concept is very similar to the already proposed Node 4/DHS - with the exception that the DHS would have NDS ports on Nadir & Zenith, and also be not be shortened like your Node is.

[sdsds]

So in a way this would be like a "Zero ISPRs" node?

[manboy]

And here's my node concept attached to the ISS, I was too lazy to draw PMA-2 but it would be attached to the forward CBM. You would probably only be able to use two of the axial ports at a time but this concepts frees up the CBMs on Harmony nadir and zenith.

Do you mean that it would be attached to PMA-2 via APAS, or attached to the forward CBM of Node 2 - in which case PMA-2 would have to be moved (possibly to the forward port of your Node)?

PMA-2 would be attached to the forward CBM of the Cygnus derived node.

This concept is very similar to the already proposed Node 4/DHS - with the exception that the DHS would have NDS ports on Nadir & Zenith, and also be not be shortened like your Node is.

I realize this, but my idea around a Cygnus derived node as opposed to Node STA is that it may have lower development costs (standard bus and wouldn't have to be adapted for other launch vehicles) and it would give ESA an opportunity to repay NASA while investing in the Italian economy.