Careful... not all the volume is dedicated to pressurized cargo - some have equipment in the pressurized volume - and some of that is lost on the hatch mechanism/opening swept volume and the "free space" (space for the astronauts to get inside and get the cargo out - hint: Progress has NO free space: you unload it from the top down...)You may be interested in this old presentation from the early Cygnus design days. The actual "basic" PCM we ended up with is somewhere in between the "regular" and the "+" version in that presentation, with a total pressurized volume of 18.7 m3, and a useable cargo volume of about 12-13 m3. The "enhanced" version (to go with the liquid-second-stage Taurus II) has a whopping 19m3 of useable cargo volume (out of about 26m3 total pressurized vol).Moral(s) of the story: a) Not all volume is pressurized and b) Not all pressurized volume is useable for cargo.Do not pay too much attention to the spacecraft sketches - much has changed (single main engine, location of RCS jets, location of grapple fixture, etc. etc.) However, it is a curious insight into the design process... how much changes in less than two years!
Also, why not have the Recoverable return module return racks as well? Seems like an asset NASA would want especially if a rack malfunctions and needs to be repaired on the ground rather than rebuild another and trash the previous one.
Quote from: Robotbeat on 04/29/2010 08:22 pmQuote from: bad_astra on 04/29/2010 08:17 pmWill Cygnus be used for reboost?No, wrong nominal attachment location (big moment arm wrt ISS center of mass.) Right now the only docking position in the U.S. side suitable for reboost has an APAS in it (Cygnus PCM uses a CBM)QuoteGood question! Also, is a fuel-only cygnus possible, which can be used as a tug?Yes, the SM was designed to be a self-standing spacecraft (power, comm, C&DH, RCS, star trackers, etc.)And if you add a remote manipulator arm...
Quote from: bad_astra on 04/29/2010 08:17 pmWill Cygnus be used for reboost?
Will Cygnus be used for reboost?
Good question! Also, is a fuel-only cygnus possible, which can be used as a tug?
Orbital Sciences has issued its May 2010 progress update report for the Cygnus spacecraft. It can be read at http://www.orbital.com/CargoResupplyServices/.
Quote from: Freddie on 05/29/2010 01:56 amOrbital Sciences has issued its May 2010 progress update report for the Cygnus spacecraft. It can be read at http://www.orbital.com/CargoResupplyServices/.I wonder why they say "up to 2000kg", if the actual design can hold 2700kg+.
The CDR included two Cygnus PCM configurations. A standard configuration will carry up to 2,000 kg of cargo for the ISS, and will be used in the COTS demonstration mission in 2011 and the first two missions under the Cargo Resupply Services (CRS) contract between 2011 and 2012. An enhanced configuration will carry up to 2,700 kg of cargo for CRS missions between 2013 and 2015.
A hypothetical question: Are there any plans or suggestions that Cygnus may have an optional configuration like that of the HTV with a much smaller pressurised module and an unpressurised cargo rack?
The current Cygnus fact sheet (©2010 Orbital Sciences Corporation. FS006_08g) does not provide dimensions (other than volume) for the Pressurized Cargo Module. Yet those must now be set, as the manufacturing pathfinder article is well into production. Are length and diameter values available from some source other than the fact sheet?
Here's a great article about Cygnus being assembled by Thales Alenia Space (TAS) in Torino, Italy.BBC News'/Jonathan Amos' "Spaceman" Blog: "The private spaceships taking shape in Torino".www.bbc.co.uk/blogs/thereporters/jonathanamos/2010/07/cygnus.shtmlThe article refers to a "37-inch hatch, specially developed by TAS". I thought Cygnus is going to use the CBM hatch (which is 50-inches in diameter)?
What I find hilarious is how the article goes to great lengths to show how much more sophisticated ATV is from its "American cousin" That may be true technically, but Cygnus is more robust operationally (Ie can lift racks, berth to multiple ports) for less cost.technology, isnt that a good thing?
What I find hilarious is how the article goes to great lengths to show how much more sophisticated ATV is from its "American cousin"
Quote from: Ronsmytheiii on 07/08/2010 07:15 pmWhat I find hilarious is how the article goes to great lengths to show how much more sophisticated ATV is from its "American cousin" How is it "American" if it is being built in Italy? - Ed Kyle