That's because the shuttle has been designed to fly manned. It cannot be flown unmanned as Russian Buran shuttle was able to do. But this is simply a design philosofy issue of the shuttle. Adding unmanned flight possibility would probably have added costs and would needed much more time for tests since the computer technology wasn't that good those days. It is pretty complicated thing to launch the shuttle unmanned and land it unmanned compared to the capsules... But still Russians were able to do it. (and I as well don't want to bash NASA, I just say the facts. NASA shuttle is flying today and Buran is not.)Swampcat":4g1l423x said:I understand the need for some testing, but let's look back at the beginnings of STS. You would have thought, with such a complicated and non-traditional vehicle (side-mounted payload), there would have been some unmanned test flights. But there weren't. The first test of the system was full-up and manned.
What comes to testing Ares 1, I think that is certainly as much a publicity issue as technical need. NASA need to show that Constellation program is progressing and this is also a great opportunity to collect some flight data of the new systems and design.