Asteroid close approaches: analysis and potential impact detection Andrea Milani 1, Steven Chiesley 2, Paul Chudas 2, Giovanni B. Valsecchi 3 1 Dipartamento di Mathematica, Universita di Pisa, Pisa, Italy 2 Jet Propulsion Laboratory, California Institute of Technology, USA 3 IAS-CNR, Roma, Italy Introduction The last ten years have seen tremendous progress in our ability to assess the risk that an asteroid or comet might collide with the Earth. ... Pasadena, Jet Propulsion Laboratory. ...