Today’s scientists are already hard at work on new ideas for spaceflight in the future. New technology is being developed to help propel spacecraft into Earth orbit — and beyond. NASA researchers are studying ways to create more powerful and more efficient rockets. Engineers are considering things such as energy beamed from the ground, ions, and plasma as possible concepts for next-generation engines. Next to all of these super-high-tech ideas, one spaceflight possibility sounds remarkably simple — string.