Soft Robot To Solve Landing Problem, Brave Asteroid?

The asteroid belt is full of opportunities and unknowns, rich in resources and scientific mysteries. 

How do you land and move around safely on these tiny bodies? This is a question that many engineers have considered. When conventional hardware robots land on the surface of a fragile asteroid, there is a high risk that they will destroy the structure of the surface, making it impossible to obtain valid samples or conduct sustained detection.

A new type of "soft robot" could provide a breakthrough for asteroid missions.

01 Fragile asteroid faces hard landing problem

Landing a robotic spacecraft safely on the moon or planet is already very difficult. Landing on an asteroid is even more difficult.

Unlike giant planets. The surface gravity of asteroids is extremely weak, perhaps even a few millionths of that of Earth. Microgravity environment brings great challenges to spacecraft landing and activities. The traditional "hard landing" method relying on thrusters is difficult to achieve accurate control, and it is easy to destroy the loose surface structure of the asteroid, which will seriously affect the study of the composition and evolution history of the asteroid.

NASA's OSIRIS-REx mission took a very conservative approach to asteroid Bennu. "We didn't want to deal with the uncertainty of actual contact with the surface for longer than necessary," Moreau said. So they devised a scheme to spy on the asteroid in 16 seconds with a long sampling arm.

With current technology, we are still a long way from a true asteroid "landing."

02 Slow Landing: The vision of a soft robot

In view of the characteristics of the microgravity environment, Professor Jay McMahon's team at the University of Colorado has put forward a bold idea: the development of "soft robots" - AoES, to achieve a soft landing of asteroids. This robot makes full use of weak forces such as electromagnetic adsorption and electrostatic adhesion for landing and surface activities, does not need to rely on propellants and mechanical anchoring, and can achieve a "zero collision" soothing landing.

The soft robot is designed in the shape of multiple petals, similar to water lilies. The petals are made of elastic material that can cover large areas of the asteroid's surface area without damaging the surface topography, and they can also rotate and stretch, using orbital speed and solar radiation pressure to adjust their orbit and slow down.

Soft robots can use the surface charge distribution of asteroids for electromagnetic adsorption. The surface of the asteroid is filled with various dust particles, which create complex charge distributions and electric fields, just as geckos use molecular interactions to attach to the wall, soft robots can also attach to the surface of the asteroid by controlling the charge cloud of some petals.

Another way to attach is to use electrostatic force. Although the electrostatic force on the surface of the asteroid is weak, the soft robot can accumulate enough electrostatic adhesion through the huge surface area. Adjusting the charge of some petals allows the soft robot to move. This mode of motion does not require fuel propulsion and does not cause secondary contamination of the asteroid.

03 Long-term monitoring and resource utilization

If the soft landing is successful, soft robots will be able to operate on the surface of the asteroid for a long time to carry out a variety of scientific exploration. It can be dotted with sensors on the surface to monitor magnetic fields, heat flow, charge distribution and other information to reveal the formation mechanism and evolution history of the asteroid. In the long run, this is of great significance for the development and utilization of asteroid resources

04 Technical difficulties: navigation, power and control

The concept of using soft robots to land on asteroids is very attractive, but it also faces many technical challenges, the most critical issues are navigation and control.

To achieve accurate landing and surface navigation in the complex and unknown asteroid environment, soft robots need to have obstacle avoidance and autonomous planning capabilities. Compared with rigid body, the dynamics and control system of soft robot is more complex. Every deformation of petal arm will change the overall mass distribution and dynamic parameters. The control algorithm must be efficient and accurate, and have sufficient adaptability to unknown environment.

Long-duration spaceflight also poses serious challenges to the materials and structures of soft robots. It must be able to withstand high radiation and extreme temperature differences, and have the ability to self-repair in the event of failure.

Reducing mass and improving structural strength is another challenge that needs to be broken through in this field. To operate in extreme microgravity environments, soft robots must be thin and light, but too weak a structure is difficult to power motion and sampling tasks, so it must ensure the strength and rigidity required to perform the task without adding too much mass.

05 The future can be expected

Despite the challenges, the dream of a soft landing continues to drive progress and innovation in this field. The University of Colorado team, which has received a NASA research grant since 2017, is currently exploring whether some of its soft robotics technology could serve in-orbit satellite maintenance and space junk cleanup.

It remains to be seen whether soft robots will be able to pioneer asteroid exploration for humans.