Research published this week in Science Advances shows that it may be possible to create rocket fuel that is much cleaner and safer than the hypergolic fuels that are commonly used today. And still just as effective. The new fuels use simple chemical “triggers” to unlock the energy of one of the hottest new materials, a class of porous solids known as metal-organic frameworks, or MOFs. MOFs are made up of clusters of metal ions and an organic molecule called a linker.