We previously reported on a NIAC-funded project called the Lofted Environment and Atmospheric Venues Sensors (LEAVES) mission to study the atmosphere of Venus. While the technology behind the idea is still in development, it has already inspired a team of students from Worcester Polytechnic Institute (WPI) to develop a supporting satellite mission to launch and communicate with the Leafs. Her article, which is part of her bachelor's thesis, describes in detail how these new sensors can be used and what challenges lie ahead.
As a reminder, the main USP of LEAVES is that it is a cost-effective way to collect data about the atmosphere of Venus – at least from an altitude of around 100 km down to 30 km, where a lot of interesting atmospheric physics takes place. They are designed without a propulsion system and therefore glide down independently and send back data about the local pressure, temperature, composition of the atmosphere and the orientation of the probe via an inertial measurement unit like those used in drones.
They aren't expected to last long, but the short time they are present in the atmosphere could provide insight into several open questions about Venus, such as which compound absorbs near-ultraviolet light in the upper atmosphere or what the local concentration of carbon monoxide is. However, their distribution across the planet's surface is a crucial part of such efforts – and this is where the team's mission design at WPI comes into play.
As Fraser discusses in this video, Venus's environment places great demands on technology.
Their mission design revolves around two spacecraft being put together for launch and approach to Venus, but then breaking apart into completely different orbits. One of them, Demeter, is responsible for launching the LEAVES. The other, Persephone, is named after Demeter's daughter, who kidnapped the Greek counterpart of Venus to the underworld. It will be left in a higher orbit and will be responsible for transmitting the data collected by LEAVES back to Earth.
Demeter had to make two important design decisions – one was where to deploy the LEAVES, and the second was how. The team developed a deployment strategy for eight LEAVES every 20 meters around the planet, for a total of 144 probes. Importantly, these will be used in day/night light to investigate what role the difference between day and night might play in the sulfur dioxide cycle on Venus.
The deployment presented a different challenge – the team chose 18 miniature casings, each attached to a small solid rocket booster with hydrazine. Demeter would orbit the planet at an altitude of about 235 km and shoot eight LEAVES around the planet every 20 degrees. These SHEETS would descend through the atmosphere – some around the equator, others around the poles – and unfold their slip form about 150 km from the surface. At about 100 km they began sending data back to Persephone, which was waiting above them. Upon completion of its operational mission, Demeter itself would deorbit and begin to burn up in the atmosphere of Venus.
Cosmic Voyages discusses the LEAVES project.
Photo credit – Cosmic Voyages YouTube channel
Persephone has a much simpler task: she uses a rocket booster to reach a 2000 km orbit and waits patiently for the LEAVES to deploy. It then uses a high-power antenna to receive signals from the LEAVES' relatively weak communications systems and store them on its local hard drive. Once all the data is collected, Persephone sends it back to Earth.
All but one component on both satellites has a very high technology readiness level (TRL-9). The only exception is the deployment tubes for the LEAVES, which have an expected TRL of 1-2, meaning they would require more development and testing before they are ready for prime time.
There is currently no deadline for this development and testing as LEAVES is still only a NIAC project and has not been selected for a mission to Venus. Given the increasing interest in exploring our sister planet, it's likely that a similar mission will one day be launched – and perhaps some of the team that spent much of their senior year working on this project will finally get to work on it Version be involved creates it there.
Learn more:
Baxter et al. – Design and analysis of a SmallSat as a communication relay for Venus atmospheric probes
UT – Floating LEAVES could characterize Venus' atmosphere
UT – Atmosphere of Venus
UT – Venus has clouds of concentrated sulfuric acid, but life could still survive
Mission statement:
Model of the Demeter spaceship, including the insert tubes for the LEAVES.
Credit – Baxter et al.
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