The Institute of Space and Astronautical Science (ISAS), Japan, plans to launch the LUNAR-A mission in 2004. The scientific objective of the mission is to explore the lunar interior using seismometry and heat-flow measurements. Two penetrators containing two seismometers (horizontal and vertical components) and heat-flow probes will be deployed from a spacecraft onto the lunar surface, one on the nearside and another on the farside of the moon. The seismic observations are expected to provide key data on the size of the lunar core, as well as data on deep lunar mantle structure. The heat flow measurements at two penetrator landing sites will also provide important data on thermal structure and bulk concentrations of heat-generating elements in the moon. Combining these data, we will be able to obtain much stronger geophysical constraints on the origin and evolution of the moon than has ever been obtained.