It's very simple the ancient invented new things almost everyday and those plans are stored in the database as long the ancients lived and not acendent.
the deadules needs a new power source to strengthen the shield and make it possible for energy based weapons.
we know the ancients build puddlejumpers and warships like aurora and orian.
they have a powerfull power supply but it's to andvanced for us to copy.
in there words it's millions of years beyond us.
what power source did they have before that that's better then we have now but not to advanced to build.
they recorded every bid of technology since they hit computer age in there development.
world war 1 or 2 they build tanks those plans still excist but the tank evolved to what it is today and those plans excist.
look in the database for power source that is better then we have now but not millions of years beyond us.