  The High Resolution Instrument Infrared Spectrometer (HRI-IR) onboard the
Deep Impact Flyby spacecraft detected H2O, CO2, and CO in the coma of the
dynamically young Oort cloud comet C/2009 P1 (Garradd) post-perihelion at a
heliocentric distance of 2 AU. Production rates were derived for the parent
volatiles, QH2O = 4.6e28, QCO2 = 3.9e27, and QCO = 2.9e28 molecules s-1, and
are consistent with the trends seen by other observers and within the error
bars of measurements acquired during a similar time period. When compiled with
other observations of the dominant volatiles of Garradd, unexpected behavior
was seen in the release of CO. The H2O outgassing of Garradd, increasing and
peaking pre-perihelion and then steadily decreasing, is more typical than that
of CO, which monotonically increased throughout the entire apparition. Due to
the temporal asymmetry in volatile release, Garradd exhibited the highest CO to
H2O abundance ratio ever observed for any comet inside the water snow line at
60 percent during the HRI-IR observations. Also, the HRI-IR made the only
direct measurement of CO2, giving a typical cometary abundance ratio of CO2 to
H2O of 8 percent but, with only one measurement, no sense of how it varied with
orbital position.
