## 4 Future Data
### Synthetic Aperture Radar  
There are advanced plans for continuity of SAR data acquisition covering the polar regions. The lifetimes of current commercial missions extend for a number of years and provide capacity to complement publicly-funded missions. The operators of these commercial platforms also have plans for next generation satellites to extend their capacity into the future. This will likely see the addition of improved capabilities, including higher resolution, larger coverage and more interferometric and polarimetry capabilities.  
Four high-profile future publicly-funded missions are currently planned and will have a significant role in providing data for the polar regions. The first satellite in the Sentinel series will be a C-band SAR satellite collecting at a range of spatial resolutions from 5 to 100 m [98]. At the time of writing, Sentinel-1a had been launched on 3 April 2014, sent back its first images on 12 April 2014, and was still in commissioning phase; Sentinel 1-b is scheduled for 2015, both with a seven-year operational lifespan. As with the multispectral Sentinels previously discussed, data are expected to be free and open, with distribution channels still to be defined.  
The second mission is JAXA's ALOS-2, which carries the L-band PALSAR-2. Like other SARs, PALSAR-2 has a wide variety of imaging modes in multiple polarizations and with resolutions ranging from 1 m to 100 m. Successfully launched on 24 May 2014, the PALSAR-2 antenna was successfully deployed on 26 May 2014, and has been declared stable ([[https://directory.eoportal.org/web/eoportal/satellite-missions/a/alos-2](https://directory.eoportal.org/web/eoportal/satellite-missions/a/alos-2)]([https://directory.eoportal.org/web/eoportal/satellite-missions/a/alos-2](https://directory.eoportal.org/web/eoportal/satellite-missions/a/alos-2))). Data quality and availability remain to be seen.  
The third publicly funded SAR satellite system is the next phase of the Canadian Radarsat program called the Radarsat Constellation. This is planned for launch in 2018 and comprises three C-band SAR satellites to provide daily monitoring of Canada's land and oceans and the ability to acquire imagery of most of the world's surface. Full mission details are available at [[http://www.asc-csa.gc.ca/eng/satellites/radarsat/](http://www.asc-csa.gc.ca/eng/satellites/radarsat/)]([http://www.asc-csa.gc.ca/eng/satellites/radarsat/](http://www.asc-csa.gc.ca/eng/satellites/radarsat/)). While it is early in the process and details still need to be determined, initial plans are for this satellite system to be operated by the Canadian Space Agency on a noncommercial basis, which should allow more open access to data.  
The fourth mission, still in development, is the U.K.-based NovaSAR-S. With seed funding from the U.K. government, this is another commercial partnership. A constellation of S-band (3.1-3.3 GHz) imagers with a variety of medium-resolution imaging modes (6-30 m) is planned for a 2015 launch, although this is tentative. With an emphasis on low-cost delivery and data priced similar to traditional optical missions, there is some hope that there will be a proportion of the data available for low cost or free civil and scientific use. However, the scope and delivery methods for such data have not yet been defined.