Destination Venus: DAVINCI+
NASA is returning to the Venusian surface after 30 years
Venus. The brightest entity which adorns a moonless night sky. Named after the Roman goddess of love and beauty, a naming quite aptly reflecting humankind’s fascination with this planet for centuries and beyond. Often called ‘Earth’s Twin’ or ‘Earth’s Sister’ for its similar size, mass and composition, the planet is thought to have once hosted surface water or even life, which justifies the interest scientists have in Venus.
The planet holds a rather special place in cultures across the world ranging from the Sumerians to the Mayans serving as a god, as a symbol of feminine beauty and fertility with myths on it found in almost all major civilizations around the world. Its beauty has inspired poets, writers and artists to create works that transcend time, etching the place of Venus in global culture.
Venus was pushed into the limelight when in September of 2020, a group of astronomers in the United Kingdom announced that they had found traces of a chemical compound called “Phosphine” in the thick sulfuric acid clouds of Venus. The announcement made headlines across the science community since it is extremely hard for phosphine to exist in the Venusian atmosphere and no known abiotic process is observed to produce this compound on terrestrial planets. This was the closest we came to identifying the presence of lifeforms in the Venusian atmosphere but all the excitement was short-lived, as another group of scientists tried to replicate the initial observations and couldn’t reproduce the groundbreaking results. They concluded that the observed data likely corresponded to sulfur dioxide and not phosphine.
The idea of lifeforms existing in the dense atmosphere of Venus has been toyed around for quite some time now. The surface of the planet reaches a smouldering 462°C due to the Carbon-Dioxide rich atmosphere giving rise to the strongest greenhouse effect found in the Solar System. Simply, life is just too hard to exist on the surface. However, scientists theorize that a ‘biozone’ in the Venusian atmosphere exist, at about 50km from the surface, in the sulfuric acid clouds where the conditions are perfect for microbial life to survive. Due to the lack of data, we cannot confirm these hypotheses. But NASA has prioritized Venus and the agency would be sending two missions to study Venus in detail.
On June 2, 2021, NASA announced two missions to Venus as winning proposals for its 2019 Discovery Program competition. There were four proposals in the race to being selected by NASA, out of which two - DAVINCI+ and VERITAS were termed the winning proposals.
DAVINCI+
Missions like DAVINCI+ under the aegis of the Discovery program is not like the flagship missions of NASA but is designed to complement them by providing valuable data by launching smaller, less resource-intensive, less time-consuming missions.
DAVINCI+ which stands for Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus, consists of an orbiter and a probe to primarily study the Venusian atmosphere and its evolution. DAVINCI was the name given to the descent module of a future Venus mission, which would piggyback on a carrier spacecraft built by Lockheed Martin, and was put forward for the NASA Discovery program in 2015 but lost out to Psyche and Lucy. Later, the orbiter and lander phase were joined and the name revised to DAVINCI+ and submitted again for the Discovery Program in 2019 which it now won along with VERITAS.
MISSION OBJECTIVES
Study the Venusian atmosphere, its origin, evolution and how it is different from Earth and Mars’.
Collect data that could give clues about the history of water and lower atmopshere processes
And finally study the surface properties, especially the tectonic, volcanic and weathering processes of the Venusian terrain
MISSION CONCEPT
The mission incorporates an orbiter and a descent probe, the latter spending almost an hour dropping through the dense atmosphere collecting all possible data using its instruments onboard. The descent phase sphere is derived from the Pioneer Venus Large Probe design which flew to Venus in 1978, almost 30 years ago!
The launch of the mission is scheduled for FY2030 as per the latest report. The mission would encounter Venus about four months after launch and would make two flybys of the planet during which the orbiter would study the atmosphere and map the surface composition. Two years after encountering the planet, the probe would be released to the surface towards the Alpha Regio region and the orbiter placed in an orbit around the planet.
The probe would be slowed using two parachutes, which keeps the probe in flight for about an hour during which in-situ data collection is initiated and data relayed back to Earth with the orbiter acting as a relay station. Even though the probe is not required to survive the descent, it can sufficiently collect and relay data for about 17 minutes on the surface.
Lockheed Martin would be the major industrial partner in the mission providing the aeroshell and backshell of the descent probe, parachutes to position the probe in the proper descent trajectory, telecom systems and the carrier spacecraft/orbiter. You can read more about the partners here.
ORBITER PAYLOAD
The Lockheed Martin built orbiter would carry an array of imaging sensors (UV, Near IR and a Wide Field Mode) and telecommunications equipment to complement the in-situ data collection by the descent probe. The imaging equipment is supplied by Malin Space Science Systems (MSSS) which also supplied the JunoCam and OSIRIS-Rex NavCam, enabling better imaging of the Venusian terrain. The primary focus of the study is the Tesserae, a unique Venusian feature that could be compared to Earth’s continents suggesting that plate tectonics isn’t just restricted to Earth.
DESCENT PROBE PAYLOAD
VENUS Mass Spectrometer (VMS) - Built by Goddard Space Flight Center
VENUS Tunable Laser Spectrometer (VTLS) - Built by Jet Propulsion Laboratory.
These two instruments would collect data on trace gas species and key elemental isotopes to understand better how the Venusian atmosphere turned out to be what it is now. A key focus of the study is noble gases since they are inert and gives clues as to how the atmosphere has evolved over the years.
Venus Atmospheric Structure Investigation (VASI) - would carry out surveying of the atmosphere during entry and descent providing the most detailed composition profile of the atmosphere.
Venus Descent Imager (VenDI) - Built by MSSS, the imager would provide high-quality imagery which wouldn’t be able to be obtained from orbiter based imaging sensors. The imager would also provide 3D topographical data of the Alpha Regio mountainous region, famous for its topographical features, which could shed light on the planet’s sedimentary and tectonic history.
The Discovery 2019 had four missions in running to the final spot with at most two getting the final cut. Each mission had received $3 million each for their nine-month study phase to mature and develop the concepts and submit a concept study report on which a committee would select the most promising mission(s). VERITAS and DAVINCI+ being selected would now receive funding from NASA which is estimated to be about $400-$500 million each and a development period of nearly 5 years, which is the standard time frame of a Discovery mission. Both missions are scheduled to launch somewhere during 2028 - 2030.
NASA has also come up with a cool trailer for the mission which I highly suggest that you should see.