During the spacecraft’s flight it passed just 517 miles above the rocky planet’s surface, where it picked up the radio signal, says NASA.
“I was just so excited to have new data from Venus,” said Glyn Collinson, an astronomer at NASA’s Goddard Space Flight Center.
NASA says the flyby actually took place last July but they are just now releasing their analysis of the data.
It was the first time new measurements have been taken of Venus since 1992.
And the experts say that the planet’s upper atmosphere was an order of magnitude thinner last year than on the previous occasion it was measured.
NASA has now published a study that confirms that the planet’s upper atmosphere goes through “puzzling changes” during an 11-year solar cycle.
Scientists say that Venus, like Earth, has an electrically charged layer of gas at the upper edge of its atmosphere called the ionosphere, which naturally emits radio waves that can be detected by instruments.
Venus and Earth are twin planets, both of them rocky and similar in size and structure.
But unlike Earth, Venus has a toxic atmosphere and unsurvivable surface temperatures of 864 degrees Fahrenheit, or 462 degrees Celsius.
This was the third flyby that the solar probe has made of Venus, with each journey around it designed to fly it closer the sun.
Watch: First American in space, Alan Shepard, used astronaut diaper before liftoff in 1961