Opportunity is Dead

Opportunity looked back over its own tracks on August 4, 2010. Credit: NASA/JPL-Caltech.

Feb 18, 2019

The Mars Exploration Rover (MER B) Opportunity traveled across the face of Mars for 15 years.

Opportunity was launched on July 7, 2003 and after a six month journey, it bounced to a landing inside Meridiani Planum on Sunday, January 5, 2004. Opportunity was meant for no more than a six month sojourn in the frozen desert of Mars, but the data it gathered compelled NASA managers to continue its mission indefinitely.

Opportunity was preceded by its twin rover, Spirit. However, in June 2009, Spirit became stuck in a sand trap and was unable to maneuver into a position where its solar cells could keep its batteries charged. After it lost power in the deep cold of the 2009 Martian winter, the rover ceased communications on March 24, 2010. On May 25, 2011 NASA announced that it would no longer send signals to Spirit, signifying the end of the “Spirit recovery project”.

Mars presently has an atmosphere that is less than 1% of Earth’s atmospheric density at sea level. It is composed almost entirely of carbon dioxide, although nitrogen and argon make up about 3%, with trace elements less than 1/10%. The temperatures on Mars vary with a maximum of 20 Celsius and a minimum of -140 Celsius. The atmosphere is so thin that blowing winds exerted almost no pressure on the two rovers.

Among Opportunity’s most significant findings was the vast collections of so-called “blueberries” on the surface. Note that the term “blueberry” was not used because of their color, but because the mission team was stunned by their presence within the matrices of several large rocks. They are so abundant that mission managers said they were like “blueberries in a muffin.”

As previously written, the blueberries bear a striking resemblance to stone spherules on Earth called “Moqui marbles”, found in the Southwestern United States. Moqui marbles are unusual because of their interior construction: the majority of them are iron shells enclosing a sandstone core. They are also found embedded in the walls of some canyons and within large boulders. Some of the Moqui marbles are hollow.

On Mars, the blueberries come in various sizes, with the smallest gathered into drift-like dunes that literally stretch from horizon to horizon. Some of the largest lie within cracks inside shattered polygonal paving stones. The hematite blueberries are often associated with the expanses of shattered quartz, although the reason remains obscure to planetary scientists. The quartzite pavement is split into regular polygons with wide cracks that are most often filled with hematite blueberries. They exhibit fractures that radiate in concentric arcs from what appear to be hollow impact zones, and have been roughly etched, or eroded away on top. The cracks have edges that are sometimes razor-sharp. Many are undercut.

It is unusual that dark hematite is so intimately bound up with white silicon-dioxide rock. Could there be a connection between silica and hematite on Mars? Could electric arcs transmute elements: reforming the atomic structure of silicon (with 28 particles in its nucleus) into that of iron (with 56)? Perhaps that connection could also explain the Moqui marbles with their iron oxide and silicon dioxide composition.

Previous Picture of the Day articles highlighted the dune fields on Mars, their carved faces, and the craters associated with them. Since standard geological and astrophysical theories offered no explanations except those that depend on comparisons with Earth-based formations, it was concluded that electricity is the one unifying factor that explains how they all were created.

Stephen Smith

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