NASA's "mole" on Mars has failed. After nearly two years of attempting to dig the InSight lander's heat probe – nicknamed the mole – into the Red Planet's surface, engineers have finally given up. The InSight lander arrived on Mars in November 2018. Its main purpose is to study the planet's deep interior in order to help us understand the history of the solar system's rocky worlds. The lander has three main instruments to help it do that: a seismometer to catch vibrations travelling through the ground, a radio to precisely measure Mars's rotation and learn more about its metal core and a setup called the Heat Flow and Physical Properties Package (HP3) to measure the heat flowing out of the planet's centre.

This paper presents a time-efficient scheme for Mars exploration by the cooperation of multiple drones and a rover. To maximize effective coverage of the Mars surface in the long run, a comprehensive framework has been developed with joint consideration for limited energy, sensor model, communication range and safety radius, which we call TIME-SC2 (TIme-efficient Mars Exploration of Simultaneous Coverage and Charging). First, we propose a multi-drone coverage control algorithm by leveraging emerging deep reinforcement learning and design a novel information map to represent dynamic system states. Second, we propose a near-optimal charging scheduling algorithm to navigate each drone to an individual charging slot, and we have proven that there always exists feasible solutions. The attractiveness of this framework not only resides on its ability to maximize exploration efficiency, but also on its high autonomy that has greatly reduced the non-exploring time. Extensive simulations have been conducted to demonstrate the remarkable performance of TIME-SC2 in terms of time-efficiency, adaptivity and flexibility.

Mission controllers appear to have lost contact with a tiny craft that was Europe's big hope for Mars exploration. The paddling pool-sized "Schiaparelli" lander appeared to have made its way safely through the harsh atmosphere of Mars and onto its surface. But something appears to have gone wrong while it did so – and mission controllers are now unable to speak with it. The lander sent communications to its mothership, the Trace Gas Orbiter, on its way down. But the signal was lost before touchdown.