Expansion of the Young Oxygen Rich Supernova Remnant G292.0+1.8

G292.0+1.8 is the only Galactic supernova remnant (SNR) known to exhibit all the expected characteristics of a core-collapse SNR: stellar ejecta enriched in oxygen, an active pulsar and its wind nebula, and evidence for interaction of the supernova blast wave with circumstellar material. G292.0+1.8 thus provides a special opportunity for studying the evolution of core-collapse SNRs. We have recently carried out detailed radio, X-ray, optical and infrared studies of this important object, and have now been awarded a Chandra Large Project in 2006 to make a further 530 kilosecond exposure. The spectacular images and spectra that will result will allow us to carry out the most complete investigation of a core-collapse SNR ever carried out. We here propose corresponding ATCA observations which, when compared to earlier ATCA observations in 1994, will allow a measurement of the expansion of this young SNR. These data will yield the evolutionary state of the SNR, the density profile into which it is expanding, and the geometric centre of the explosion. These contemporaneous ATCA data are also needed to make detailed comparisons with our forthcoming Chandra observations.