Esri (/ˈɛzriː/, a.k.a. Environmental Systems Research Institute) is an international supplier of geographic information system (GIS) software, web GIS and geodatabase management applications. The company is headquartered in Redlands, California.
As of Aug 21 2017, Esri announced availability of satellite imagery to the OSM community directly through their existing World Imagery Service.
Esri World Imagery provides one meter or better satellite and aerial imagery in many parts of the world and lower resolution satellite imagery worldwide. The map includes 15m TerraColor imagery at small and mid-scales (~1:591M down to ~1:72k) and 2.5m SPOT Imagery (~1:288k to ~1:72k) for the world. The map features 0.3m resolution imagery in the continental United States and parts of Western Europe from DigitalGlobe. Additional DigitalGlobe sub-meter imagery is featured in many parts of the world. In the United States, 1 meter or better resolution NAIP imagery is available. In other parts of the world, imagery at different resolutions has been contributed by the GIS User Community. In select communities, very high resolution imagery (to 0.03m) is available down to ~1:280 scale. You can contribute your imagery to this map and have it served by Esri via the Community Maps Program. View the list of Contributors for the World Imagery Map.
Sources: Esri, DigitalGlobe, Earthstar Geographics, CNES/Airbus DS, GeoEye, USDA FSA, USGS, Getmapping, Aerogrid, IGN, IGP, and the GIS User Community
Using Esri imagery in editors
The easiest way to do this is to select the “Esri satellite imagery” layer as an option in either iD or JOSM.
Esri and its imagery contributors grant Users the non-exclusive right to use the World Imagery map to trace features and validate edits in the creation of vector data. Users that create vector data from the World Imagery map may want to publicly share that vector data through a GIS data clearinghouse of its own or through another open data site. This public sharing could be achieved through ArcGIS Open Data or the OpenStreetMap (OSM) Initiative. For ArcGIS users that want to contribute such vector data to OSM, Esri provides applications and services directly accessible from ArcGIS platform. Users acknowledge that any vector data contributed to OSM is then governed by and released under the OpenStreetMap License (e.g. ODbL).
For More Info, visit: http://goto.arcgisonline.com/maps/World_Imagery
Helpful information about Using Imagery to be aware of.
According to user jgravois on Github who seems to be an ESRI employee, the imagery might be used if the mapper does not use ArcGIS Editor for OpenStreetMap:
the updated document @cloveman shared grants the community permission to use our World Imagery to trace features and validate OSM edits even when ArcGIS tools are not being used.