A new Mars orbiter, MAVEN, is about to head for the red planet in hopes of helping scientists reveal the story behind The Great Escape – the disappearance of a thick, moist atmosphere that converted the planet from a relatively warm, wet world potentially hospitable for life to a cold, dry, pale-red dot in the night sky.
NASA has scheduled the launch for 1:28 PM Eastern Standard Time Nov. 18. If all goes well, the craft will embark on a 10-month journey, arriving next September.
The $617-million mission is the last one on the books for a 20-year program that has systematically peered, scraped, and drilled at the fourth rock from the sun to understand its workings and figure out whether life could potentially have called it home, if briefly. Each mission was designed to lay the groundwork for the next, technologically as well as scientifically.
So it is with MAVEN, short for Mars Atmosphere and Volatile Evolution Mission. The craft draws on the Mars Reconnaissance Orbiter's design, tweaked for this mission, to fill in a critical missing piece of the puzzle – how the planet's atmosphere evolved over time and the factors that thinned it. The processes responsible are thought to take place largely in the planet's upper atmosphere.
To help solve the puzzle, MAVEN will work closely with the rover Curiosity, currently traversing Gale Crater en route to Mt. Sharp, where it will explore rock formations in its continued effort to reveal more about the planet's ancient surface environment. Two of the eight science instruments have counterparts on the Curiosity to make simultaneous measurements at the bottom and top of the Martian atmosphere.
MAVEN “is not as sexy as the rovers going over the planet,” said mission launch director Omar Baez during a prelaunch briefing Friday. But “this is kind of like a weather satellite for Mars....It's real science.”
It's science compelling enough for Bruce Jakosky, a planetary scientist at the University of Colorado at Boulder and the mission’s lead scientist, to have spent 10 years refining the concept for the one-year mission, which could last up to six years at Mars if all goes well and NASA opts to extend MAVEN's assignment beyond its initial term.
“I think it's that valuable and that important for understanding Mars,” Dr. Jakosky said during an extensive interview about the project shortly after Curiosity landed on Mars in August 2012.
Each trip along the MAVEN's elliptical orbit will bring it to within 93 miles of the Martian surface and back out to a distance of nearly 4,000 miles above the planet. In addition, the craft is slated to make five “deep dips” that will carry it to within about 78 miles of the surface. The orbits are designed to allow the craft's instruments to explore processes at work throughout the entire depth of Mars' upper atmosphere. This is where the long-term erosion of the planet's gaseous envelop is suspected to have occurred.
The 2.7-ton spacecraft has a 37.5-foot span when its solar panels are fully extended – about the length of a school bus. The panels form a gull-wing shape to help stabilize the craft during the deep dips.
The orbiter also carries communications equipment that will allow it to serve as an additional radio-relay station for rovers on the surface. For now, that task largely falls to the Mars Reconnaissance Orbiter, launched in 2005, and Mars Odyssey, which was launched in 2001. The European Space Agency's Mars Express orbiter also is circling the planet. India's $71-million Mars Orbiter, launched Nov. 5, will remain in Earth orbit until Nov. 30, when the country's space agency plans to ignite the final engine burn that will put it on course for Mars.
If all goes well with both new missions, MAVEN should arrive at Mars about two days ahead of India's orbiter.
MAVEN's launch is bittersweet for the planetary science community. Until now, NASA's Mars exploration program proceeded in a sustained, systematic way with missions typically alternating between orbiters and rovers or landers. MAVEN is the last mission on the books under this program.
The agency has two more missions on its docket for this decade – InSight, a lander designed to drill beneath the Martian surface for 2016, and a rover mission in 2020 aimed at collecting and storing Mars rock and soil samples for later return and analysis. The US also is contributing a key instrument for the European Space Agency's ExoMars rover, which the Europeans plan to launch in 2018.
But InSight came from a different planetary exploration program within the US space agency. The sample-caching rover, long sought by the US planetary-science community as a precursor to a sample-return mission, is the natural next step after 20 years of following water and now finding encouraging evidence that the planet could have been habitable in its distant past, notes Casey Dreier, a policy analyst with the Planetary Society in Pasadena, Calif. The society is a strong advocate for a robust space-exploration program.
Last fall, in response to the tougher budget environment, scientists taking part in NASA's Mars Program Planning Group set out options for a Mars exploration program from 2018 to 2024.
But beyond the 2020 rover, nothing is even in the planning stage, Mr. Dreier says. NASA and the White House “are not doing very much to plan to get those samples back.”
The press for fiscal austerity in Washington is sapping the political enthusiasm for committing the country to sample-return missions, at least for now, since such an effort would require “three big flagship-class missions in a row,” Dreier says, referring to missions that carry price tags of $2 billion to $3 billion each.
Researchers say they hope a new program emerges. To come as far as scientists have in answering key questions about possible past life on Mars and not be able to make the final push for an answer would be unfortunate, they say. Missions in a new program also would help pave the way for eventual human missions to the red planet.
Sample return missions, for instance, would require a means to land on Mars, take off again, and rendezvous with the craft that will return the samples. The same techniques would be needed if people constituted the payload instead of rocks.
Although Mars has proven to be a difficult planet to reach, the US has an enviable success rate. Of 36 missions launched by Russia, the US, Europe, and Japan since 1960, only 13.5 have succeeded, roughly a 38 percent success rate. Looking only at US missions, however, 13 of 18 have succeeded, an enviable 0.722 batting average.
Researchers say they are concerned that if a new program doesn't emerge soon, the technical expertise and hands-on experience that built such success will erode and be hard to recapture.