Almost no empty seats remained in the large auditorium for opening day of the 2024 Transformative Vertical Flight conference devoted to helicopter research. Håvard Grip, a chief engineer at NASA, stood before the waiting crowd of aeromechanical engineers to deliver his presentation on the many triumphs—and the downfall—of Ingenuity, the record-setting helicopter that flew scores of missions on Mars before ultimately crashing in mid-January 2024.

“We learned a ton,” said Grip of the process the agency used to design Ingenuity, which had opened an entirely new frontier in helicopter research with its flights through Mars’s thin, otherworldly air. Everything from the design to the testing protocol had been developed from scratch. He described the groundbreaking helicopter’s testing lab as a “poor man’s” wind tunnel: to measure wind movements on their prototype, the researchers used a giant arm that latched onto the copter and swung it around inside a 25-foot room that replicated Mars’s atmospheric conditions.

From a mechanical engineering perspective, Ingenuity was a decisive victory, completing 71 successful flights. But the helicopter also had an Achilles’ heel: the autonomous navigation software that was so crucial to the mission’s success also struggled to orient the craft in bleak, featureless terrain because it relied too much on small-scale features such as rocks as waypoints. On what would become the helicopter’s final flight, when NASA directed Ingenuity to land on a bland, sandy flat, the craft lost its bearings, tilted over sharply, and drove a rotor into the sand, snapping off the blade’s tip.

“In retrospect, we can see how that terrain is different from other kinds of terrains that we’ve flown in,” said Grip, who had previously acted as Ingenuity’s chief pilot in the helicopter’s early days. “And it turns out that it was just a little bit too challenging for Ingenuity to handle, and so that is a lesson, right?”

Ingenuity has flown its last mission, but within a decade, at least one of its technological children may embark on a voyage to distant planets. Several speakers at the conference presented new or updated designs for helicopters that benefited from the knowledge gained fromtheir pioneering parent’s off-world flights.

At the time, the conference was galvanized by the overall sentiment that NASA saw helicopters as an integral part of planetary exploration. Now, however, after a recent mix of good and bad news, the future is murkier.

AN AIRBORNE RENAISSANCE

There are compelling reasons to include helicopters in interplanetary missions. Rovers tend to be slow and simply can’t navigate some of the more formidable terrains. On the other hand, NASA has designed helicopters capable of reaching peak speeds of almost 70 miles per hour on Mars, ascending to the peaks of its mountains and then descending into the depths of its craters left over from ancient oceans. The maneuvering prowess of one design should even give it the ability to explore the insides of caves.