Dust modelling of fast-flyby missions: Implications of in situ measurements

Using the Divine approach to modelling of cometary dust distributions within the dust envelope, together with the Reference Model parameters established by the Comet Halley Environment Working Group, predicted flux and fluence values are presented for each of the Giotto Dust Impact Detection System (DIDSY) subsystems. Implications for returned DIDSY data is discussed with particular reference to mass-size distribution and particle fluence as a fuction of time. It is also shown that the first particle impact event recorded by any of the DIDSY subsystems is likely to be of sufficient mass to penetrate the front shield of the Giotto spacecraft.