SPECIAL.- The existence of extraterrestrial life has been one of the biggest dilemmas of the scientific community for decades, and Saturn’s moon Enceladus has given possible signs of life and NASA has presented a mission project that can function as an orbiter and lander and would respond to the search for alien life hosted by the neighboring satellite.
NASA’s Cassini spacecraft left a legacy of discoveries when it completed its 13-year mission to Saturn in 2017. One of the biggest finds: The icy moon Enceladus has an underground ocean that discharges water into space. The fissures cut at the south pole have temperatures warm enough to suggest that the moon’s core is warming the ocean.
On Earth, similar places called hydrothermal vents are hotspots for life.
Scientists and engineers at the Johns Hopkins University Applied Physics Laboratory in Maryland want to investigate this moon in situ and have presented their Orbilander mission project.
“We know that there is a subsurface ocean and we have every reason to suspect that it is habitable,” said Shannon MacKenzie, planetary scientist and lead author of the Orbilander mission concept study.
“We have the technology to go and test it, thanks to the water pens.” With an estimated budget of $ 2.5 billion, Orbilander is a flagship mission concept being explored for the next 10-year planetary science survey, a community-produced report produced every 10 years to guide the priorities of the NASA mission.
How will Orbilander search for extraterrestrial life?
Orbilander would start orbiting Enceladus for roughly 200 days, not an easy task with Saturn’s giant gravity field on its side. The team plans to rely on station maintenance maneuvers developed for other missions and choose orbital trajectories that balance the health of the spacecraft with scientific return.
Despite their bright appearance in Cassini images, Enceladus’ feathers are not very dense: Orbilander will fly through something more like a cloud than a garden sprinkler. The plume particles will be funneled into the scientific instruments at high speeds as the spacecraft moves forward, requiring the team to come up with ways to gently slow them down so they don’t pulverize.
Much of the time in orbit will be spent looking for the right place to land. Despite Cassini’s extensive monitoring of Saturn and its moons, not enough high-resolution topographic data is available for Enceladus’ south pole.
Once a location is found, Orbilander would turn to its side and become a lander. It would descend using terrain-relative navigation similar to what OSIRIS-REx will use to capture a sample from the asteroid Bennu, and what the Dragonfly mission to Saturn’s moon Titan will use to fly around the surface. Two nuclear power sources will keep Orbilander running for a year and a half.
Orbilander would rely on a complex set of instruments to determine whether Enceladus’ water has a mix of life-sustaining chemicals as we know it, and would look for amino acids, lipids and cells. Instruments include mass spectrometers for weighing and analyzing molecules, a seismometer, a microscope, and a DNA sequencer. For remote sensing, the spacecraft would have cameras, radar probes, and a laser altimeter.
Orbilander would give answers in the year 2050
Unlike most other moons with subsurface oceans, Enceladus’ geysers offer a unique opportunity to sample the water without drilling the surface. Orbilander will not only access the columns by flying through them in orbit, but will also capture material from the columns that fall to the surface after the spacecraft lands.
If endorsed in the next 10-year survey and selected by NASA for development, Orbilander would not launch until 2038 and reach Enceladus until at least 2050, when Enceladus’ south pole is in sunlight.