2021-04-01 15:00:53 GMT2021-04-01 23:00:53(Beijing Time) Sina English US and European scientists have called off a controversial balloon test flight that was to take place in Sweden’s far north in June, part of a disputed solar geoengineering experiment to artificially cool the planet. A team of Harvard University scientists had been planning to launch a high-altitude balloon from the Esrange Space Station in the Swedish town of Kiruna, to test whether it could in future carry equipment to release solar radiation-reflecting particles into the Earth’s atmosphere. The project has been dubbed SCoPEx, short for “Stratospheric Controlled Perturbation Experiment.”