Engineers at NASA’s Jet Propulsion Laboratory (JPL) are testing a landing system for a proposed future mission to reach Jupiter’s icy moon Europa.
Europa distinguishes itself as a target for future space missions due to the presence of an ocean of liquid water under its icy crust, in conditions that could be favorable for life.
This system for the proposed ‘Europa Lander’ is an evolution of the hardware used in previous NASA landing missions. It was tested in August and NASA has now released images of its performance (https://vimeo.com/884255444).
It includes the architecture used for the “sky crane maneuver” that helped lower NASA’s Curiosity and Perseverance rovers onto the Martian surface, giving the lander the stability it needs to land.
Although this landing architecture was developed with Europa as a target, it can be adapted for use on other moons and celestial bodies with challenging terrain, NASA reports.
Four flanges, suspended from a simulated propulsion descent stage overhead, keep the body at the level of the lander. The four legs passively adapt to the terrain they encounter as the lander continues to descend. Each leg consists of a four-bar linkage mechanism that controls the posture of the leg before and during landing. The legs are pre-loaded down with a constant spring force to help them adjust and compress the surface they encounter before landing, giving them more traction and stability in the during and after landing.
Acting as a protective plate, the keel provides protection to the bottom of the spacecraft from potentially damaging terrain. The keel also resists the shearing action of the soil with which it is in contact.
When the keel makes contact with the surface, the sensors activate a mechanism that quickly locks the swivel “hip” and “knee” joints of the legs, resulting in a table-like posture. At this point, the task of ensuring the stability of the lander shifts from the flanges to the legs. This change keeps the lander level after unloading the zip ties.
If the keel does not touch the ground during the landing process, sensors on each leg can also declare a landing. After the leg joints are locked, the keel is suspended above the landing pad and the lander is supported only by four legs.