Building on the considerable achievements of the current generation of mapping missions (Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter), next generation missions to Mars will make highly targeted, high resolution measurements to further the exploration of the Mars environment and the search for life on Mars. At the University of Toronto we have designed two new instruments, the Mars Broadband Atmospheric and Rock Spectrometers (MarsBARS). MarsBARS will carry out a very sensitive search for low abundance trace gases in the Mars atmosphere and small deposits of uncommon mineralogy. Particular scientific objectives of this mission are: 1) A new understanding of Mars atmospheric chemistry through simultaneous profile measurements of atmospheric constituents 2) Search for low-level bacterial or volcanic activity through the detection of methane 3) Search for locations of hydrothermal springs through detection of opal-A silicate deposits. The MarsBARS package has two Fourier Transform spectrometers adapted respectively for high spatial resolution nadir imaging and high spectral resolution solar occultation atmospheric measurements. It will make a relatively small number of sensitive measurements at high spectral and spatial resolution and have the flexibility to select targets both on the surface and on the atmospheric limb.

Standard references show the effects of carrier phase jitter on the performance of digital communications equipment as curves of bit error rate versus signal-to-noise ratio for constant values of jitter variance. In any real system, the variance consists of a relatively small constant component and a component which is inversely proportional to signal-to-noise ratio. This correspondence presents revised calculations of bit error rate for a number of values of the constant variance component and the proportionality constant. The resulting curves are shown to agree with experimental results, and are useful for predicting performance of real systems.