Is there much known about how its payload to LEO & GTO stacks up in comparsion to other rockets in the same launch class as it?All it gives on Wiki for it is a very rough figure to LEO of 5,000Kg & nothing else.
Quote from: Star One on 10/04/2012 08:41 pmIs there much known about how its payload to LEO & GTO stacks up in comparsion to other rockets in the same launch class as it?All it gives on Wiki for it is a very rough figure to LEO of 5,000Kg & nothing else.http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdfPage 6.
Quote from: strangequark on 10/04/2012 11:24 pmQuote from: Star One on 10/04/2012 08:41 pmIs there much known about how its payload to LEO & GTO stacks up in comparsion to other rockets in the same launch class as it?All it gives on Wiki for it is a very rough figure to LEO of 5,000Kg & nothing else.http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdfPage 6.Thanks for that link.Maybe I am reading this wrong but it does compare that equally to its commercial rival the Falcon 9 going by this.http://www.spacex.com/Falcon9UsersGuide_2009.pdf
Quote from: Star One on 10/05/2012 07:51 pmQuote from: strangequark on 10/04/2012 11:24 pmQuote from: Star One on 10/04/2012 08:41 pmIs there much known about how its payload to LEO & GTO stacks up in comparsion to other rockets in the same launch class as it?All it gives on Wiki for it is a very rough figure to LEO of 5,000Kg & nothing else.http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdfPage 6.Thanks for that link.Maybe I am reading this wrong but it does compare that equally to its commercial rival the Falcon 9 going by this.http://www.spacex.com/Falcon9UsersGuide_2009.pdfI'm not sure I understand your comment. Antares in its current configuration is a Delta-II comparable. Falcon 9 is more like an Atlas V 401.
But obviously my assumption was incorrect as they are not comparable at all and not the same class of vehicle.
Quote from: Star One on 10/07/2012 12:18 pmBut obviously my assumption was incorrect as they are not comparable at all and not the same class of vehicle.Antares and F9 1.1 are not in the same class, but I wonder if the same holds true for the current F9 1.0.I've been eagerly waiting for the NASA ELV page to finally include Antares performance data after the vehicle was included in the NLS-II contract.
Has Orbital talked much recently about the potential performance of Antares with a liquid second stage? They're doing the "right thing" with their focus on meeting NASA's CRS mission requirements using Castor-30 variants. But would Antares performance jump much closer to Atlas V 401 if it used something more like a Centaur?
Quote from: sdsds on 10/07/2012 10:10 pmHas Orbital talked much recently about the potential performance of Antares with a liquid second stage? They're doing the "right thing" with their focus on meeting NASA's CRS mission requirements using Castor-30 variants. But would Antares performance jump much closer to Atlas V 401 if it used something more like a Centaur? Depends on the path taken. Speaking in a completely unofficial capacity, I've gotten Antares with liquid upper stage to throw upwards of 10000kg with kerosene, doing back-of-the-spreadsheet calculations. So, yeah, with an optimal upper stage, it's probably Atlas class.
Awesome. I know Dr. Elias has mentioned here on NSF that he kind of regrets not being able to go with a liquid upper for Taurus II Antares. But nothing says you couldn't do it in the future!
Quote from: Robotbeat on 10/08/2012 04:25 pmAwesome. I know Dr. Elias has mentioned here on NSF that he kind of regrets not being able to go with a liquid upper for Taurus II Antares. But nothing says you couldn't do it in the future!Yeah, I would love to hear his opinion on XCOR's piston engines. Granted, they're still strolling in the gentle foothills of the mountain range of qualifying an engine as flight hardware.
Quote from: strangequark on 10/08/2012 02:56 pmQuote from: sdsds on 10/07/2012 10:10 pmHas Orbital talked much recently about the potential performance of Antares with a liquid second stage? They're doing the "right thing" with their focus on meeting NASA's CRS mission requirements using Castor-30 variants. But would Antares performance jump much closer to Atlas V 401 if it used something more like a Centaur? Depends on the path taken. Speaking in a completely unofficial capacity, I've gotten Antares with liquid upper stage to throw upwards of 10000kg with kerosene, doing back-of-the-spreadsheet calculations. So, yeah, with an optimal upper stage, it's probably Atlas class.Awesome. I know Dr. Elias has mentioned here on NSF that he kind of regrets not being able to go with a liquid upper for Taurus II Antares. But nothing says you couldn't do it in the future!
What are the reasons they have gone with a solid upper stage, why not something like an off the shelf Centaur instead?
Quote from: Star One on 10/08/2012 10:50 pmWhat are the reasons they have gone with a solid upper stage, why not something like an off the shelf Centaur instead?Because there is no such thing. ULA is not going help them become a competitor.
What are the reasons they have gone with a solid upper stage
Let me point out that the Antares first stage is roughly 85% of an Atlas V first stage (both thrust and mass). So it wouldn't sound too difficult to get in the ball park of performance. Particularly for LEO. My only question is: is there a market for it?If Falcon 9 becomes a reliable work horse, and adapts to DoD's needs, then there will be a surplus of rocket models between EELV and F9/FH. And that's just for the US. Then you have Angara and LM-5 also entering the market. I simply don't see much space for them.