landers

A lander is a spacecraft designed to descend from space and come to rest on the surface of a celestial body. Unlike orbiters that stay in orbit or rovers that move across the surface, a lander typically remains stationary after touchdown and carries instruments to study the local environment, geology, and atmosphere or to perform experiments in situ. Landers may operate alone or as part of a larger mission that includes an accompanying rover or orbiter.

Descent and landing involve a sequence of braking and stabilization steps to achieve a controlled touchdown. For bodies with atmospheres, entry heat protection, a deceleration system such as parachutes or retrorockets, and landing gear or crushable structures are used to reduce impact. For airless bodies, descent may rely on retrorockets and legs or other landing mechanisms. After landing, power is usually supplied by solar panels or a radioisotope power unit, and communication with Earth is typically relayed through an orbiting spacecraft or direct from the lander when feasible. Instruments are tailored to surface science, including cameras, seismometers, spectrometers, weather sensors, and sampling or contact probes.

Notable examples include lunar landers from the Surveyor program; Viking landers that carried the first successful Mars surface experiments; the Phoenix and InSight landers on Mars; the Philae lander on comet 67P/Churyumov–Gerasimenko; and lunar or Martian landers from the Chang’e and Tianwen programs. Landers remain a core method for gathering high-value, in situ data from surfaces beyond Earth.