It is not a simple matter to differentiate unsuccessful from successful experiments. . . .[Most] work that is finally successful is the result of a series of unsuccessful tests in which difficulties are gradually eliminated.
Robert H. GoddardThe reason many people fail is not for lack of vision but for lack of resolve and resolve is born out of counting the cost.
Robert H. GoddardHow many more years I shall be able to work on the problem I do not know; I hope, as long as I live. There can be no thought of finishing, for 'aiming at the stars' both literally and figuratively, is a problem to occupy generations, so that no matter how much progress one makes, there is always the thrill of just beginning.
Robert H. Goddard