Lunar Reconnaissance Orbiter (LRO) was launched in 2009 to study and map the Moon and is now completing its fifth extended science mission. The LRO (see Figure 1) hosts a payload of seven different scientific instruments. The Cosmic Ray Telescope for the Effects of Radiation instrument has characterized the lunar radiation environment and allowed scientists to determine potential impacts to astronauts and other life. The Diviner Lunar Radiometer Experiment (DLRE) has identified cold traps where ice could reside and mapped global thermophysical and mineralogical properties by measuring surface and subsurface temperatures. The Lyman Alpha Mapping Project has found evidence of exposed ice in south polar cold traps as well as global diurnal variations in hydration. The Lunar Exploration Neutron Detector has been used to create high-resolution maps of lunar hydrogen distribution and gather information about the neutron component of the lunar radiation environment. The Lunar Reconnaissance Orbiter Camera (LROC) is a system of three cameras [one wide-angle camera and two narrow-angle cameras (NACs)] mounted on the LRO that capture high-resolution black-and-white images and moderate resolution multispectral (seven-color band) images of the lunar surface. These images can be used, for example, to learn new details about the history of lunar volcanism or the present-day flux of impactors. The Miniature Radio Frequency (Mini-RF) instrument is an advanced synthetic aperture radar (SAR) that can probe surface and subsurface coherent rock contents to identify the polarization signature of ice in cold traps. The Lunar Orbiter Laser Altimeter (LOLA) has been used to generate a high-resolution, 3D map of the Moon that serves as the most accurate geodetic framework available for co-locating LRO (and other lunar) data. The data produced by the LRO continue to revolutionize our scientific understanding of the Moon, and are essential to planning NASA's future human and robotic lunar missions.

In this chapter, we review the contribution of space missions to the determination of the elemental and isotopic composition of Earth, Moon and the terrestrial planets, with special emphasis on currently planned and future missions. We show how these missions are going to significantly contribute to, or sometimes revolutionise, our understanding of planetary evolution, from formation to the possible emergence of life. We start with the Earth, which is a unique habitable body with actual life, and that is strongly related to its atmosphere. The new wave of missions to the Moon is then reviewed, which are going to study its formation history, the structure and dynamics of its tenuous exosphere and the interaction of the Moon's surface and exosphere with the different sources of plasma and radiation of its environment, including the solar wind and the escaping Earth's upper atmosphere. Missions to study the noble gas atmospheres of the terrestrial planets, Venus and Mars, are then examined. These missions are expected to trace the evolutionary paths of these two noble gas atmospheres, with a special emphasis on understanding the effect of atmospheric escape on the fate of water. Future missions to these planets will be key to help us establishing a comparative view of the evolution of climates and habitability at Earth, Venus and Mars, one of the most important and challenging open questions of planetary science. Finally, as the detection and characterisation of exoplanets is currently revolutionising the scope of planetary science, we review the missions aiming to characterise the internal structure and the atmospheres of these exoplanets.