>> Another Russian scientist,
Konstantin Tsiolkovsky wrote extensively about the concept of jet propulsion.
In 1903, he published a manuscript titled
Exploration of the World's Space with Reaction Machines.
The Tsiolkovsky formula described the mathematical relation
between the changing mass of a rocket as it burns fuel,
the velocity of exhaust gases and the rocket's final speed.
This is considered one of the foundations of the science of astronomics.
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>> It was Russian physicist Konstantin Tsiolkovsky who drew up the first concrete
plans for a space flight.
As early as the turn of the century, he proved that only liquid fuel could give
rockets the thrust necessary for overcoming the Earth's gravitational pull.
>> Robert Goddard was an American scientist and
inventor who launched history's first liquid-fueled rocket in 1926.
Primarily working independent of government support,
Goddard built a series of rockets over the next 20 years,
progressively developing increasingly sophisticated devices.
He's credited with theorizing that rockets could function in the vacuum of space,
thereby conceptually opening the way for
travel to distant objects in the solar system.
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>> Robert Goddard, the American rocket pioneer, yanking inventor,
dreamer; they called him the Moon Man and laughed but on his own,
he went ahead designing, inventing, and testing.