It takes a lot of delta v to get to Mercury and orbit the planet, so multiple sling shot manuvers were done to keep the cost of the probe from being excessive. Neil

Yes I can make a hard copy of pictures and text I put on slashdot, and other websites, but the copies get lost, the websites purge the old stuff or disappear completely. My computers loose the stuff on them about once per year. Redundant times 4 or 5 is costly and/or time consuming. Even deciding what we want to keep long term is time consuming. there does not appear to be any good solution. Neil