Two NASA rovers weathered Martian dust storm

By Fakir Balaji

Hyderabad, Sep 25 (IANS) Two Mars rovers, Spirit and Opportunity, launched in 2003 by the US National Aeronautics and Space Administration (NASA), weathered a massive dust storm on that planet this July, a senior NASA scientist told the International Astronautical Congress (IAC) here Tuesday.

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“There was a massive dust storm on Mars in July. The two robotic rovers, located near Gusev crater and Victorian crater, survived the raging storm remarkably, as the magnitude of the solar attenuation (reduction) was much more than they were designed to withstand,” Jet Propulsion Laboratory (JPL) deputy director James E. Graf said at a presentation on the incident on the red planet.

Showing video pictures relayed by the reconnaissance orbiter spinning about 300 km from the distant planet’s surface, Graf said the dust storms blocked sunlight to the rovers and threatened their ability to generate energy through their solar arrays.

“Though mission controllers at the JPL feared one or both of the rovers may get disabled due to the massive impact of the storm, they survived and resumed driving since Aug 24 after the dust lifted gradually,” Graf told the delegates.

JPL controllers placed the rovers in a passive mode to reduce power consumption to the minimum and turned off the experiments they were conducting when the dust storm kicked up.

Showcasing some of the reconnaissance orbiter’s stunning pictures for the first time to the delegates and the media, Graf said the dust storm, which raged for over five weeks in the Martian atmosphere, appeared to be seasonal.

“The scientific community is studying the impact of the storm, which started from the northern hemisphere of the red planet and moved across towards the southern hemisphere. The data will help us to design and build the next generation of rovers to withstand such sudden and unpredictable Martian storms,” Graf pointed out.

Both the rovers have moved away from their original landing spot by seven to 11 km during the last three years, conducting various experiments and analysis. The dust storms were so intense and dense that the sunlight penetration into the Martian atmosphere was reduced to a mere two to five percent from 90 to 100 percent.

The latest pictures relayed by the orbiter reveal the presence of phyllosilicate mineral rocks in the crater that would have taken three-four billions years to form.

“Similarly, data from other pictures of the Martian surface in the north pole and south pole indicate the presence of geysers and gullies with moisture contained that would have formed at least 300 million years ago,” Graf noted.

As part of NASA’s Mars exploration programme, which includes three previous successful landers – the two Vikings in 1976 and Pathfinder in 1997 – the present rovers were sent to explore the Martian surface and geology.

Spirit, launched on June 10, 2003, landed in Gusev crater nearly seven months later on Jan 4, 2004 while Opportunity, launched on July 7, 2003 landed in the Meridiani Planum on the opposite side of the planet on Jan 25, 2004.

The Mars Exploration Rover (MER) mission’s scientific goals are to search for and characterise a wide range of rocks and soils that hold clues to past water activity on the red planet. Project manager Peter Theisinger of JPL and principal investigator Steven Squyres, professor of astronomy at Cornell University, lead the mission.

“Though the rovers were designed and built to operate for 90 days, they are still functioning even three years after landing on Mars. The mission funding, which was initially $820 million, has been extended till this month-end,” Graf said.

The scientific data and analysis from both rovers indicate their landing sites were once saturated for a long time with liquid water, containing high salinity and acidity.

In recognition of the vast amount of scientific information amassed by both rovers, two asteroids have been named in their honour – 37452 Spirit and 39382 Opportunity.

The HiRISE (high resolution imaging science experiment), onboard the Mars Reconnaissance Orbiter (MRO) was launched in August 2005 to investigate deposits and landforms resulting from geologic and climatic process over billions of years on the red planet. It provides a bridge between the orbiter and the rovers to relay very high-resolution images to the mission control at the JPL.