MAVEN's approach to Mars studies will be quite different from that taken by recent probes dispatched to the Red Planet. Instead of rolling about on the surface looking for clues to the planet's hidden heritage, MAVEN will orbit high above the surface so it can sample the upper atmosphere for signs of what changed over the eons and why.
The mission will be the first of its kind and calls for instruments that can pinpoint trace amounts of chemicals high above Mars. The results are expected to let scientists test theories that the sun's energy slowly eroded nitrogen, carbon dioxide and water from the Martian atmosphere to leave it the dry, desolate world seen today.
"Scientists believe the planet has evolved significantly over the past 4.5 billion years," said David Mitchell, MAVEN's project manager for NASA's Goddard Spaceflight Center in Maryland. "It had a thicker atmosphere and water flowing on the surface. It wasn't like Earth, but it was not like it is today."
Before any of those studies can take place at Mars, though, the spacecraft will see a few months of intense launch processing at NASA's Kennedy Space Center in Florida. The MAVEN spacecraft, short for Mars Atmosphere and Volatile Evolution, stands inside the Payload Hazardous Servicing Facility at Kennedy where engineers and technicians are taking the first steps in getting it ready for launch in November.
The instruments, systems and all-important power-generating solar array wings on the 5,400-pound spacecraft (once fueled) will be tested repeatedly inside the clean room at the Kennedy facility. Engineers also will fuel the spacecraft so it can maneuver through space and arrive safely in orbit around Mars.
MAVEN arrived at Kennedy Aug. 2 on a C-17 transport aircraft.
"A big part of our schedule was getting to the Cape on time," Mitchell said. "We have marked this as a big milestone we had to hit because if you miss this launch period, you stand down for 26 months until the planets are aligned again."
Technicians spent the first week reinstalling equipment that was removed for the flight such as the high-gain antenna the spacecraft uses to transmit data to Earth.
The spacecraft will be powered on during its second week at Kennedy and tests will begin in earnest soon afterward, Mitchell said.
When the testing and fueling is complete, a payload fairing will be placed around MAVEN and it will be trucked to Launch Complex 41 at Cape Canaveral Air Force Station. MAVEN will be hoisted atop a United Launch Alliance Atlas V for launch Nov. 18 to begin a 10-month cruise to Mars.
Testing the MAVEN calls for stringent guidelines since the spacecraft will face the stresses of spaceflight throughout its mission. For example, the two solar arrays will have to withstand differing pressures of flying from the vacuum of space to even the tenuous layers of the Martian upper atmosphere during each orbit.
MAVEN carries instruments that can take samples of the Martian atmosphere directly when it flies as low as 77 miles above the surface, plus devices that will analyze the planet from more than 3,700 miles away.
"MAVEN is going after something the others haven't," Mitchell said. "It's going to look at the current composition of the upper atmosphere and how solar storms and other factors changed the atmosphere. We'll then be able to project back in time to see how it was in an earlier epoch."
The MAVEN flight comes on the heels of remarkable successes by NASA's Mars exploration efforts, including the landing a year ago of the rover Curiosity that has conducted detailed geological studies on the Martian surface.
"MAVEN will help us understand the climate history, which is the history of habitability." said Bruce Jakosky, planetary scientist at the University of Colorado Boulder and MAVEN's principal investigator, "Although MAVEN is not going to detect life, it's trying to understand the environment that might have been able to support life."
Mars has long intrigued NASA and planetary researchers for a host of reasons including the fact that its surface does not look unlike some places on Earth, although its atmosphere would be far from hospitable to humans. Since NASA landed two Viking probes on the planet in 1976 and followed up with a series of orbiters, landers and rovers from 1996 to last year, Earthbound observes have been flabbergasted by numerous discoveries including the potential for abundant liquid water.
"There's something about going to another planet that's very exciting," Mitchell said. "When you're talking about going to Mars, it isn't hard to get great people to come work the job. And ultimately, the mysteries that MAVEN will help decipher should be a treasure trove for the science community.
By Steven Siceloff
NASA's Kenendy Space Center