High Altitude Venus Operational Concept
High Altitude Venus Operational Concept (HAVOC) is a set of crewed NASA mission concepts to the planet Venus. It contemplates the entirety of the human portions of the missions to be conducted from lighter than air craft or from orbit and de-emphasizes traditional landings.
Venus is a planet with a runaway greenhouse effect, with surface temperatures and pressure of 873 °F (467 °C) and 93 bars (9,300 kPa) respectively. Hence, human missions to Venus have historically been thought impractical, if not impossible. However, Venus has advantages for crewed travel, such as Earth-like gravity (.90 Earth gravity), an atmosphere that provides a level of protection from solar and interstellar radiation, and a much greater proximity compared to Mars.
Whereas all ground missions measured their operational time in minutes or hours, the Soviet Vega missions found success in launching small balloons, that operated until their batteries were exhausted (days). At 55 km (34 mi) altitude, the atmosphere of Venus is 27 °C (81 °F) and 0.5 bars (50 kPa) (the equivalent pressure to about 5,500 m (18,000 ft) on Earth). However, due to the large amount of CO
2, density for a given pressure is greater than in Earth's atmosphere, therefore breathable air acts as a buoyant gas at altitude. Concurrently, the gravity at the proposed altitude is 8.73 m/s2 versus 9.81 m/s2 on Earth's surface.
Venus has an induced magnetosphere from the interaction of its thick atmosphere with the solar wind, and its nearer proximity to the Sun brings it further within the Sun's magnetic field, which decreases the interstellar radiation levels. With the addition of the reduced deep space exposure time, the radiation levels anticipated by astronauts are potentially much less than an equivalent Mars mission.
Phase 1 involves a robotic exploration via a 31 m (102 ft) long airship. It would be used to test many of the technologies that would be used in the crewed version, including the dirigible, energy systems, and aerocapture and descent sled.
Phase 2 is for astronauts to orbit Venus. The individual components would be assembled remotely, and the crew would join the larger assembly when all the preparations are complete. There would be a return module sent to low Venus orbit ahead of the astronauts, with which they would rendezvous in Venusian orbit, before returning to Earth.
Phase 3 involves descending into the atmosphere. The aeroshell would be used for heat dissipation. A parachute would be deployed to further slow the craft, before finally inflating the airship. Once inflated, the crew would live in the airship for a period equivalent to thirty Earth days, before detaching and ascending in the Venus Ascent Vehicle.
- Arney, Dale; Jones, Chris (2015). HAVOC: High Altitude Venus Operational Concept - An Exploration Strategy for Venus. SPACE 2015: AIAA Space and Astronautics Forum and Exposition. 31 August-2 September 2015. Pasadena, California. NF1676L-20719.
- Preston, R. A.; et al. (March 1986). "Determination of Venus Winds by Ground-Based Radio Tracking of the VEGA Balloons". Science. 231 (4744): 1414–1416. Bibcode:1986Sci...231.1414P. doi:10.1126/science.231.4744.1414. PMID 17748082.