The Pre-ACE (PACE) mission is a recent addition to the NASA flight program manifest as recommended in the report, “Responding to the Challenge of Climate and Environmental Change: NASA’s plan for a Climate-Centric Architecture for Earth Observations and Applications from Space”, published in June 2010. As described in the report, the primary objective is to “make essential global ocean color measurements, essential for understanding the carbon cycle and how it both affects and is affected by climate change…”. The report also suggested that a contributed polarimeter for aerosol and cloud research be accommodated provided a partner could be found who would provide an instrument at no expense to NASA.
In the fall of 2011, NASA selected a science definition team (SDT) via an open solicitation that is composed of ocean, aerosol, and cloud scientists. The SDT is supported by an engineering team who is tasked with conducting instrument and mission design studies. Four members of the Ocean Ecology Laboratory were selected for the SDT. The SDT held three open community workshops in the fall of 2011 and spring of 2012. As of August 2012, the SDT has drafted a report for NASA Headquarters that outlines the science objectives and measurement requirements for ocean, aerosol, and cloud research. At present, PACE is scheduled for launch in the 2019 time frame.
For further information, go to the PACE website, http://decadal.gsfc.nasa.gov/pace.html.
ACE is a mission focusing on aerosols, clouds, and ocean ecosystems, in response to the NRC Decadal Survey. The ACE Ocean Science Team has prepared the 'ACE Ocean Biology White Paper', describing ocean biology mission goals and the corresponding science questions.
The ACE mission is expected to launch in 2020 or later. Recently, NASA announced the data continuity PACE (Pre-ACE) mission, with a launch date of 2018 or later. It will contain a sensor to measure ocean color and possibly a French-contributed polarimeter for aerosol measurements. ORCA is a candidate for the ocean color radiometer on PACE and ACE. At the moment, the science requirements for PACE have not been defined yet, but are expected to be similar to those of the ACE mission.
Ocean Ecology has been developing and testing a prototype for the ACE mission, the Ocean Radiometer for Carbon Assessment (ORCA). ORCA is a grating-based spectrometer with a hyperspectral resolution of about 5nm. It was designed to meet the instrument requirements formulated in the ACE Ocean Biology White Paper. Testing of ORCA's optical properties is currently on-going. Characterization results on its sensitivity to polarization have been published here.
The Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission focuses on measurements of tropospheric trace gases and coastal biogeochemical properties from geostationary orbit as recommended by the NRC Earth Science Decadal Survey report. The GEO-CAPE Ocean Science Working Group has been developing the science objectives and requirements for the coastal ecosystem component of the mission. A 'white paper' summarizing the coastal ocean biology and biogeochemistry science goals and requirements will be available shortly.
The NRC placed GEO-CAPE within the second tier of mission launches, which NASA plans to launch after 2020 (NASA 2010). "A primary objective for observing coastal ocean regions is to determine the impact of climate change and anthropogenic activity on primary productivity and ecosystem variability (NRC 2007)." The main advantage afforded by a geostationary platform versus a low-earth polar orbit is the capability to image the same regions multiple times per day. Such a capability is vital to study coastal oceans where the physical, biological and chemical processes react on short time scales from seconds to a few days.