T he Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission landed on Mars on 26 November 2018 in Elysium Planitia 1,2 , 38 years after the end of Viking 2 lander operations. At the time, Viking's seismometer 3 did not succeed in making any convincing Marsquake detections, due to its on-deck installation and high wind sensitivity. InSight therefore provides the first direct geophysical in situ investigations of Mars's interior structure by seismology 1,4. The Seismic Experiment for Interior Structure (SEIS) 5 monitors the ground acceleration with six axes: three Very Broad Band (VBB) oblique axes, sensitive to frequencies from tidal up to 10 Hz, and one vertical and two horizontal Short Period (SP) axes, covering frequencies from ~0.1 Hz to 50 Hz. SEIS is complemented by the APSS experiment 6 (InSight Auxiliary Payload Sensor Suite), which includes pressure and TWINS (Temperature and Winds for InSight) sensors and a magnetometer. These sensors monitor the atmospheric sources of seismic noise and signals 7. After seven sols (Martian days) of SP on-deck operation, with seismic noise comparable to that of Viking 3 , InSight's robotic arm 8 placed SEIS on the ground 22 sols after landing, at a location selected through analysis of InSight's imaging data 9. After levelling and noise assessment, the Wind and Thermal Shield was deployed on sol 66 (2 February 2019). A few days later, all six axes started continuous seismic recording, at 20 samples per second (sps) for VBBs and 100 sps for SPs. After onboard decimation, continuous records at rates from 2 to 20 sps and event records 5 at 100 sps are transmitted. Several layers of thermal protection and very low self-noise enable the SEIS VBB sensors to record the daily variation of the

Meteoroid impacts shape planetary surfaces by forming new craters and alter atmospheric composition. During atmospheric entry and impact on the ground, meteoroids excite transient acoustic and seismic waves. However, new crater formation and the associated impact-induced mechanical waves have yet to be observed jointly beyond Earth. Here we report observations of seismic and acoustic waves from the NASA InSight lander's seismometer that we link to four meteoroid impact events on Mars observed in spacecraft imagery. We analyzed arrival times and polarization of seismic and acoustic waves to estimate impact locations, which were subsequently confirmed by orbital imaging of the associated craters. Crater dimensions and estimates of meteoroid trajectories are consistent with waveform modeling of the recorded seismograms. With identified seismic sources, the seismic waves can be used to constrain the structure of the Martian interior, corroborating previous crustal structure models, and constrain scaling relationships between the distance and amplitude of impact-generated seismic waves on Mars, supporting a link between the seismic moment of impacts and the vertical impactor momentum. Our findings demonstrate the capability of planetary seismology to identify impact-generated seismic sources and constrain both impact processes and planetary interiors.