Japanese Lunar Exploration Program the LUNAR-A mission, and a small data relay satellite. SELENE-3 aims to return about 100 grams of samples from the Moon surface. It will be launched around 2020. However, due to financial issues JAXA is currently facing, this mission may be merged into the option-3 of SELENE-X. SELENE-X will be launched in the late 2010s, in view of Japan’s participation in Humans Lunar Activities foreseen. The SELENE-X may perform either of the following demonstrations: There are other options under study, and will be determined after the international exploration strategy has been clarified. MELOS (Mars Exploration with Lander-Orbiter Synergy) is a
Orbital station-keeping track it is also necessary to make out-of-plane manoeuvres to compensate for the inclination change caused by Sun/Moon gravitation. These are executed as thruster burns orthogonal to the orbital plane. For Sun-synchronous spacecraft having a constant geometry relative to the Sun, the inclination change due to the solar gravitation is particularly large; a delta-v in the order of 1–2 m/s per year can be needed to keep the inclination constant. For geostationary spacecraft, thruster burns orthogonal to the orbital plane must be executed to compensate for the effect of the lunar/solar gravitation that perturbs the orbit pole with typically 0.85