Launched on December 18, 1999, the MODIS ProtoFlight Model on-board the EOS Terra spacecraft (near Sun-synchronous polar orbit, 10:30 am equator crossing time) has been providing the science community global data sets for over two years. The instrument has been performing well on-orbit in terms of its spatial and spectral characterization and radiometric calibration. Many science products have been developed and validated using the MODIS Level 1B calibrated data. To be launched in April 2002, the MODIS Flight Model 1 on the EOS Aqua spacecraft (1:30 pm equator crossing time) will enhance the MODIS products by providing afternoon observations.