As a researcher, I'm interested in the GALEX mission's data. Please provide the direct URL to the GALEX data archive, explain how the archive has grown since its first release, and summarize the key changes or improvements introduced in the GR6 data release as compared to GR4/5.
Navigate to 'galex.caltech.edu'. Click on the 'Researcher Resources' link. Click on the 'Data Releases' link. Locate and extract the direct URL for the Multi-Mission Archive at STScI (MAST) from the page. Identify information regarding the growth of the GALEX data archive since its first release (GR1). Read the 'GR6 Direct Data Release (Changes Relative to GR4/5)' section to identify key changes and improvements. Synthesize all collected information to answer the task.
The agent successfully navigates to the 'Data Releases' page. The agent identifies and states the direct URL to the MAST archive as 'http://galex.stsci.edu'. The agent states that the data archive has grown by over a factor of ten since the first release (GR1) in 2004. The agent summarizes the key changes in GR6 relative to GR4/5, including: removal of 26 redundant/questionable columns and addition of 53 columns (mostly FUV measurements), and significant updates/improvements to calibrations such as flat field, flux response trend with time, FUV to NUV position correction, distortion corrections, and magnitude zero-point adjustment.