Dramatic GEO remote-sensing cost reduction is being demonstrated by the Commercially Hosted Infrared Payload (CHIRP) program, a U.S. Air Force (USAF) research and development (R&D) effort scheduled for launch late 2011. Gary Payton, USAF Undersecretary, noted in October 2008 (Brinton, 2008): “The deal … was fantastic … a fourth-of-the-world view on orbit at geosynchronous, and a year … of downlink data … for less than the cost of a launch vehicle.” Per U.S. Department of Commerce Office of Space Commercialization1: “The Air Force expects to achieve major cost savings by flying this mission as a hosted payload. They estimate it would cost approximately $500 million to launch a dedicated free flyer to satisfy 100 percent of the technical questions associated with the experiment. The hosted payload ended up costing $65 million and should satisfy 80 percent of the technical questions.”
Moreover, if CHIRP is launched in CY2011, then program duration from July 2008 contract inception to initial operational configuration (IOC) will have been just three years. As is often the case with developmental remote sensing missions, CHIRP has been paced by sensor progress. The original launch date was in mid-CY2010, but the sensor delivery date slipped. Unlike a dedicated mission, however, it was possible to shift to another satellite. This reduced much of the cost growth that might otherwise have dramatically increased expenditures—cf. sensor delay impacts to the Geostationary Operational Environmental Satellite “R” Series (GOES-R) and the former National Polar-orbiting Operational Environmental Satellite System (NPOESS) mission costs. The CHIRP program delay underscores an advantage of Group on Earth Observations (GEO)-hosting: Many host opportunities.
There are 100-plus commercial telecommunications satellites in GEO, each with a nominal 15-year life. Therefore, six must be replaced each year just to maintain operations, much less to grow capability. The reality is better. As shown in Figure D.1 (FAA, 2009), on average about 20 commercial satellites were launched annually to 2009, and that trend is expected to continue for the next decade. A commercial GEO satellite host opportunity appears at least monthly, on average.
Once a sensor is assigned to a satellite, then the sensor must be ready on the satellite’s schedule to be hosted by that satellite. If the sensor is delayed, then it is “off-ramped” from the originally specified satellite host, and later “on-ramped” to a subsequent satellite host. Considering the number of satellites launched each year, it is likely a new host can be found soon that will launch on a schedule compatible with the sensor delay. Moreover, while mission cost will rise to accommodate the sensor delay and modifications to a new host satellite, the commercially hosted mission can avoid much of the “marching army” costs associated with a delayed dedicated satellite mission. The commercial hosting option therefore offers dramatically lower cost than a dedicated satellite mission with surprising schedule flexibility and almost no data rate limitation other than the cost of renting sufficient transponder capacity.
However, main hosted-sensor trade-offs need to be considered, such as, the risk of a non-optimal host GEO longitude, and less control over the host satellite compared to a dedicated mission. Satellite location and operations are driven by the primary commercial telecommunications markets served by the satellite. Selecting a host based on its anticipated operational longitude includes the risk that the satellite operator may later place the satellite at a different longitude, either before launch or after operations at the originally planned longitude. The satellite operator also typically will not allow a hosted sensor to drive satellite maneuvers, though the operator can maneuver the satellite for sensor purposes with advance notice and coordination.
FIGURE D.1 Satellite and launch demand realized and forecast for the years 1993-2019. A dual manifest launch can launch two satellites at once. The green line depicts how many satellites were launched or are predicted to launch per year. On average, 20 commercial GEO satellites were launched each year to 2009, and this trend is expected to continue.
SOURCE: FAA, 2009.
Hosted GEO Ocean Color?
Combining the information from the Korean COMS-1 Geostationary Ocean Color Imager (GOCI) and the CHIRP mission suggests a potentially attractive GEO ocean color option. Coastal Waters Imaging (CWI) spectral requirements are not substantially tighter in bandwidth than GOCI and the CWI signal-to-noise (SNR) requirements are comparable to GOCI (NOAA, 2004; Faure, 2007). Therefore, CWI requirements suggest sensor dimensions (and mass) would be comparable to GOCI, as optical aperture and SNR are the primary sensor dimensional drivers. As GOCI mass is within the capacity of a commercial GEO satellite, CWI capability may be practical within the dimensions, mass, power, and data rate envelope for cost-effective commercial GEO hosting.