Image: AIM's asteroid lander
Engineers recently began the preliminary design of ESA's Asteroid Impact Mission mission concept and are including a lander. If the mission comes to fruition touchdown would occur in late 2022.
The asteroid lander is under study by the DLR German Aerospace Center, and is known as Mobile Asteroid Surface Scout-2, or Mascot-2. Mascot-1 is already in flight, carried on Japan's Hayabusa-2 mission, which was launched on 3 December 2014 to land on its target asteroid during 2018.