NASA’s Parker probe that is heading towards the Sun recently flew past Venus and picked up a natural radio signal. It also happens to be the first measurement of Venus’ atmosphere in almost three decades.
Parker Solar Probe’s mission is to reach as close as possible to the Sun, but for that, it will have to slow down its speed. To do so, it flew close enough to Venus that its gravity and atmosphere will lower its speed, NASA explained.
Venus’ atmosphere measured after 30 years
NASA used it as an opportunity to measure Venus’ atmosphere for the first time in three decades. Parker picked up a radio signal that was translated into sound.
“The goal of flying by Venus is to slow down the spacecraft so that Parker Solar Probe can dive closer to the Sun,” said Nour E. Raouafi, Parker Solar Probe scientist. “But we would not miss the opportunity to gather science data and provide unique insights into a mysterious planet such as Venus.”
Parker probe made this flyby on July 11, 2020, and was also the closest flyby to date. The probe was only 517 miles above Venus’ surface. The Parker probe used its FIELDS instrument to pick up the radio signal.
“Like Earth, Venus sports an electrically charged layer of gas at the upper edge of its atmosphere, called the ionosphere,” NASA’s blog post reads. “This sea of charged gases, or plasma, naturally emits radio waves that can be detected by instruments like FIELDS. When Collison and his team identified that signal, they realized Parker Solar Probe had skimmed Venus’ upper atmosphere.”
Corroborating with previous studies
The team used radio signals from Venus to calculate the density of the ionosphere that the Parker probe passed through. This was previously done in 1992 by the Pioneer Venus Orbiter. That data suggested the ionosphere was thinner during the solar minimum, the Sun’s calm phase. Earlier it was impossible to confirm, but the recent flyby might make the belief firm.
“When multiple missions are confirming the same result, one after the other, that gives you a lot of confidence that the thinning is real,” said Robin Ramstad, a study co-author.
