I don't really think this is true at all, particularly the mass fraction.I was quite surprised how big these birds were. I think though Randall hit the point when he refered to compactness of scale and materials. So unless one is working with calvenite and unobtanium the mass fraction and orbital ISP has the same limits it did some 60++ years ago.
We have the many, many new weapons:
- carbon fiber composites
- pressurised thin wall tanks (I don't think they had that 60 years ago)
- far better knowledge of propellents
- far better computing
- far better electronics
- gps
- better bearings (hydrostatic, hydrodynamic)
- canned answers in books to tricky problems that were a black art back then
- lots of proof of concepts
- cheaper materials
- better understanding of some key materials (e.g. aluminum fatigues rather easily, they didn't know that 60 years ago)
- cheap gyros
- wound tanks
- examples of what not to do (e.g. Space Shuttle; which works fine, but $$$$)
- better understanding of fundamentals of launching theory
...and on and on...
Some of these things are very significant. SSTO looks possible now, I don't think it was 60 years ago.
-julie_______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
