NASA is yet to make contact with its Mars Opportunity rover ever since a massive storm started on the Red Planet in June. Based on the longevity of a 2001 global storm, NASA scientists estimate it may be September before the haze has cleared enough for Opportunity to power up and call home, the US space agency said this week.

Scientists first observed a smaller-scale dust storm on May 30. By June 20, it had gone global. For the Opportunity rover, that meant a sudden drop in visibility from a clear, sunny day to that of an overcast one.