June 11, 2013
Dr. Geoffrey Landis is a scientist and engineer at NASA Glenn Research Center. His primary research interest is planetary exploration. In his presentation that was given to the members of the NASA Academy of 2013, he discussed past and possible future exploration attempts to Venus.
Dr. Landis first started off with an overview description of Venus. Venus, the planet that is most similar in size to Earth, is quite different due to the difference in atmosphere. It has a solar flux of 2600 W/m2 which is much higher than Earth’s. It has a slightly smaller gravitational acceleration than Earth but has a long solar day compared to Earth. A solar day on Venus is 117 Earth days. The surface pressure of Venus is 92 bar which is 92 times the atmospheric pressure of Earth at sea level. The atmosphere of Venus is mainly carbon dioxide which creates a greenhouse effect. The greenhouse effect is the reason why the surface temperature is on average 452 degrees Celsius.
As for the missions, a variety of different spacecraft were sent to Venus, primarily because there was mature technology to do so. The United States competed with Russia to send spacecraft and probes to Venus and while NASA’s Pioneer Venus was the first to reach Venus, the Russian Venera’s were the first to return pictures. The Russians sent many Venera spacecrafts and the longest probe that survived lasted for only two hours, around 127 minutes. In 1989, NASA sent Magellan, which was a radar orbiter. Magellan provided a topography map of Venus using radar and showed that Venus has had a lot of volcanic activity. After Magellan, Russia’s VEGA sent two air balloons into the atmosphere of Venus which lasted 48 hours. These balloons were Teflon coated to protect from sulfuric acid in the atmosphere and collected atmospheric data. While there were many missions sent to Venus, there is still much we don’t know about the planet. For instance, why are there no plate tectonics, are there any currently active volcanoes, what is below the surface of Venus, why are there reflective “snow” surfaces at an altitude of six kilometers or higher? Other questions such as why the atmosphere rotates in just four Earth days which creates super-fast winds and how hydrogen is not part of the chemical composition of Venus’ atmosphere make it necessary for more detailed explorations to and on Venus. To do this, Dr. Landis showed us a possible mission that involves a flyer vehicle.
The flyer vehicle would fly around 25 km at 250 degrees Celsius. This would be the most optimal level to fly around Venus. At this altitude, the density is similar to Earth and since the gravity is lower than Earth’s it would be easier to fly. Also with a higher solar flux, solar power would be much more effective on Venus than on Earth. There are challenges however, to flying in Venus’ atmosphere. Since the atmosphere produces fast winds, the aircraft would need to fly faster than the speed of the wind to travel upstream of the wind. Dr. Landis showed calculations on the altitude level required for certain wingspan lengths for the flyer to be able to fly against the wind. The proposed design of the flyer would be able to fly on Venus and collect valuable data that we currently do not have.
Dr. Landis is confident that a flyer on Venus would work and that it would return valuable information, which would help answer many of the questions proposed above. Dr. Landis is also interested in exploring other planets such as Mars using aerial vehicles. He believes that with a fast traveling vehicle, we can obtain vast amounts of atmospheric and topological data over a large region of a planet or moon. These potential exploration missions could help us understand more about our solar system in a way that we have never seen before.