During January 2007, European Space Agency (ESA) announced that the agency was studying the use of Global Positioning System (GPS) navigation in order to support launches of the Vega and Ariane. At the 2009 Paris Air Show, it was revealed that the adoption of more cost-effective engine to replace the upper stages of the Vega have been postponed due to a failure to reduce the overall costs of the launcher, making it much less worthwhile to pursue. Despite this finding, efforts to improve the efficiency of the third stage continued. At this point, the certification of all four stages of the Vega launch was anticipated to be achieved prior to the end of 2009, while the first launch was scheduled to take place during 2010. The first flight was intended to be flown with a scientific payload, rather than a "dummy" placeholder; but had intentionally avoided a costly commercial satellite. By late 2010, the first flight had been delayed into 2011.