Quote from: ugordan on 12/12/2011 07:08 pmHeh.QuoteTo clear up any marketplace confusion and provide clear differentiation between this new launch vehicle and our Taurus XL rocket.I wonder why...Was this in the press release at some point? It's gone now.
Heh.QuoteTo clear up any marketplace confusion and provide clear differentiation between this new launch vehicle and our Taurus XL rocket.I wonder why...
To clear up any marketplace confusion and provide clear differentiation between this new launch vehicle and our Taurus XL rocket.
I like it, tho one thing bothers me about this design: why choose a solid upperstage? Performance-wise that doesn't seem like a very smart move to me, as solids usually have a pretty low isp, no?
...Historically, rockets are easier to grow on the top (i.e. a bigger upper stage is cheaper than adding strapons or otherwise growing the lower stage). SO many designers, including yours truly, tend to undersize the upper stages in the initial design, to allow for a cheaper growth path...
Antares was my choice for SLS's name!We can scratch that one off the list I guess.Orbiter
Quote from: aquanaut99 on 12/13/2011 05:59 amI like it, tho one thing bothers me about this design: why choose a solid upperstage? Performance-wise that doesn't seem like a very smart move to me, as solids usually have a pretty low isp, no?There have been improvements. Castor 30 provides 301 to 303 sec ISP, closing the gap a bit on, say, gas generator hydrocarbon liquid alternatives. A solid upper stage could prove more reliable than a liquid upper stage that uses cryogenics, though that is not guaranteed. In addition, a solid upper stage requires less work (umbilicals, propellant loading) on the pad, etc.Of course a real issue was lack of liquid upper stage alternatives in the U.S. - Ed Kyle
Quote from: edkyle99 on 12/13/2011 05:03 pmQuote from: aquanaut99 on 12/13/2011 05:59 amI like it, tho one thing bothers me about this design: why choose a solid upperstage? Performance-wise that doesn't seem like a very smart move to me, as solids usually have a pretty low isp, no?There have been improvements. Castor 30 provides 301 to 303 sec ISP, closing the gap a bit on, say, gas generator hydrocarbon liquid alternatives. A solid upper stage could prove more reliable than a liquid upper stage that uses cryogenics, though that is not guaranteed. In addition, a solid upper stage requires less work (umbilicals, propellant loading) on the pad, etc.Of course a real issue was lack of liquid upper stage alternatives in the U.S. - Ed KyleWell, it may be slightly lower performance but in an upper stage it matters a lot. Plus a solid upper stage is inflexible wrt to restart and has lower insertion accuracy all things compared. I understant that you are focusing on the upsides it may have, but it's still a bad idea.
Quote from: jcm on 12/13/2011 02:55 amOf course, let's not forget the true meaning of the name for the red star Antares: "Rival of Ares". Subtle dig at the Liberty folks? :-)Considering the fact that ATK makes the upperstage for Antares and the first stage for Ares I/Liberty, highly doubtful. It was just an available constellation name.
Of course, let's not forget the true meaning of the name for the red star Antares: "Rival of Ares". Subtle dig at the Liberty folks? :-)
It was just an available constellation name.
Quote from: jcm on 12/14/2011 05:04 amIt was just an available constellation name.Star, not constellation!http://en.wikipedia.org/wiki/AntaresAntares is the beating red heart of Scorpius. Interestingly, it's one of the brightest stars close the ecliptic, apropos for planetary missions.