The text boxes in the left panel have been placed in a random order. Restore the original order by dragging the text boxes from the left panel to the right panel.
b) The 'Stratoscope' flights of 1959, concerned mainly with studies of the Sun, were remarkably successful.
a) Yet there is little resemblance between these crude vehicles and a modern scientific balloon, which has by now become an important tool.
c) Hot-air balloons date back to the year 1783, and within a few months of the first flight a French scientist, Charles, went up two miles in a free balloon.
d) The main development has been carried out by M. Schwarlschild and his team at Princeton University in the United States, in collaboration with the United States Navy.