The Journey’s End
This is Part 1 of a three-part series on Project Saturn Wheel.
Project Saturn Wheel has reached the end of its journey and the team is excited to share its big audacious ideas with the world.
It all started with a simple question: how can we reinvent the wheel in order to travel on a planet that has no solid surface to speak of?
The planet in question is — you guessed it — Saturn. The one you remember from fifth-grade science as the one with all the rings around it. For Earthlings, Saturn is the epitome of an alien world. It’s a “gas giant” that lacks an eternal rocky crust, having instead a gaseous surface and inner layers that get progressively more dense the deeper you go. All of this is wrapped up in a stormy, ammonia-rich atmosphere that gives Saturn its yellow hue.
In 1997, humankind launched the Cassini-Huygens space probe to study Saturn and its rings. That mission lasted for 20 years and revolutionized our knowledge of Saturn, but the probe studied the planet from orbit rather than venturing within the atmosphere (in fact, the probe was intentionally steered into Saturn’s atmosphere and destroyed at the end of the mission).
This made pHacktory wonder: how could we take the step beyond orbiting Saturn, and actually study the surface of the planet? How could we design a spacecraft capable of entering the atmosphere and navigating the gassy surface?
We assembled a team with the skills and enthusiasm to get the job done: Peter Doan, a recent graduate engineering student from the University of Ottawa who often ponders about how stuff works, and Ahmad Syed, a Computer Science student who dreams of using his technical skills to solve pressing problems in science & technology. Peter & Ahmad’s support team includes Project Manager Katherine Schoepp — a mechanical engineer with a background in biomedical technologies (blood test devices, prosthetic arms, and scoliosis braces) — as well as Mentors Renée Hložek (an assistant professor of astrophysics from the Dunlap Institute and the Department of Astronomy and Astrophysics at the University of Toronto who uses observations of the Cosmic Microwave Background and supernovae to understand the nature and fate of the universe); Erin Kennedy (aka Robot Girl, the founder of the environmental clean-up project Robot Missions) and Christian Gigault (a physics professor at the University of Ottawa, who is passionate about teaching and understanding how the universe operates, from microscopic properties on Earth to waves travelling through space).
The team quickly identified a number of challenges to tackle.
First, a craft entering Saturn’s atmosphere would need to avoid and withstand impacts from flying ammonia crystals. We know that wind speeds can reach 1,800 km/h. We know that those winds carry ammonia crystals. We don’t know whether the crystals are the size of a pea or the size of a basketball.
Second, the craft would need the ability to detect its atmosphere and navigate without human interference. Messages take so long to travel between Saturn and Earth that if a rogue ammonia crystal were to threaten the Saturn Wheel craft, the damage would be done long before an Earth-bound operator could discover the threat and respond to it.
Third, the craft must be able to get around using minimal energy. Energy storage adds weight, and a heavier craft is more likely to sink into the gaseous surface of the planet. Considering Saturn’s stormy weather and its distance from the sun, renewable solar energy is not a viable option.
The team’s primary interest was in navigation: designing a self-driving craft that could detect changes in the atmosphere, map its surroundings and respond to threats.
Early ideas included: (1) a mass of sensors tethered to the craft but capable of probing the atmosphere around it; (2) an adapted RADAR system designed for a high-ammonia environment; and (3) a sensor-studded “hula hoop,” inspired by Saturn’s own rings, that would surround the craft and feed it data about its surroundings.
The first idea proved to be impractical on a moving spacecraft, and the second just didn’t capture the team’s imagination. But the hula hoop idea stuck, and over time it evolved into a more sophisticated and functional design. Curious? Stay tuned for the next installment in this series, where we’ll tell you all about it!