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Wednesday, June 5, 2013

USA Air Force studying lower cost solutions for the GPS satellite constellation

With the sequester in full swing all of the government agencies are looking for potential cost savings - and the Air force's deployment of the new GPS III satellite systems are officially part of that cost savings analysis.

GPS III satellites, which are scheduled to replace the aging satellites currently in orbit are still being considered as part of the plan, but so are 'downsized' versions of the satellites - so called NavSats (also referred to as Spartan sats or NibbleSats).  More of these satellites could be deployed to help provide fewer 'minutes of outages per day' (for areas that are 'sky impaired') than the current constellation, while giving up some of the more advanced features of the GPS III - such as the Nuclear Detonation Detection System payload (NDS) that requires significant power and shielding considerations.  Reduced power and shielding, as well as some feature reductions combined with design modernization for overall weight reduction, can allow for multiple satellites to be launched into orbit at the same time - further reducing overall budget costs.  Dual satellite launches for the GPS III are being considered, but launching of four of the NavSats at a time would provide even more efficiency.  Developing the capability for Earth based launch systems for multiple GPS satellites would also be helpful to future multi-satellite missions for the Moon, or for Mars missions.

Including some additional technological design improvements to help reduce weight, design, and operational costs (such as the use of lithium ion batteries and more efficient solar panel designs, as well as modernization for reduced heat rejection), the NavSat systems could reduce on-orbit costs to as much as 1/4 of the cost of the GPSIII (from an estimated $450 million to $110 million).  This additional savings, and the potential to increase the number of working satellites in orbit (from 24 to a proposed 33) would reduce costs and increase satellite visibility for regions such as Afghanistan where some mountainous areas include masking angles of up to 60 degrees.  With 24 satellites at 60 degrees of masking, outages can be as high as 6 hours per day - but with 33 satellites, no outages are calculated to occur until you lose one or two satellites - and those outages last about an hour or less.