Sahni, VarunShtanov, Yuri2012-03-052012-03-052008-01http://hdl.handle.net/11007/336A proposal is made to test Newton’s inverse-square law using the perihelion shift of test masses (planets) in free fall within a spacecraft located at the Earth–Sun L2 point. Such an Artificial Planetary System In Space (APSIS) will operate in a dragfree environment with controlled experimental conditions and minimal interference from terrestrial sources of contamination. We demonstrate that such a space experiment can probe the presence of a ‘hidden’ fifth dimension on the scale of a micron, if the perihelion shift of a ‘planet’ can be measured to sub-arc-second accuracy. Some suggestions for spacecraft design are made.enAPSISArtificial Planetary System in SpaceExtra-dimensional gravityMONDArticle