A meeting on 19 September is expected to suggest that the cost is met from the existing EU budget or by individual member states which want to take a larger stake in the project.
The system of 30 satellites was designed to be a rival to the US global positioning system.
However, the completion date has slipped from 2008 to 2011 and the project has already cost EU member states €388m more than originally predicted.
British MPs have now raised concerns over the future of the system. The Commons European Scrutiny Committee has called for a full parliamentary debate before further progress is authorised at the Council of Transport Ministers.
The current system can photograph 600,000 square kilometres a week, but the addition of the new satellite will allow Google to capture that amount each day .
The launch on Tuesday will be broadcast live on the internet.
Some parts of Atacama have not received rainfall for 500 years - but a sudden deluge of water upset the Desert's delicate biological balance
Spitzer Space Telescope could not spot Oumuamua, suggesting that it is actually pretty small
Greenland crater one of the 25 largest impact craters on Earth
This long-sought progenitor star was identified in an image captured by Hubble in 2007