By PATRICK ROWAN
Exploring other planets is hard.
Anticipation over a fresh, new visit to Mars is building ... right along with a notable measure of anxiety. Very early next Monday morning, the Mars Science Laboratory, better known as Curiosity, is scheduled to land on the surface of the red planet.
The only question remaining, as one NASA scientist put it, is how fast it will be going when it does. In other words, MSL will either set down gently as planned ... or crash. But squarely aimed at its landing site inside Gale Crater, Curiosity will, one way or another, make its way through the thin Martian atmosphere to the surface. At least what’s left of it.
As the Associated Press put it in a story Monday, like Olympic gymnasts, the athletic rover has to “stick the landing.”
A successful touchdown would mark the start of one of the most ambitious and productive planetary missions ever attempted, but space enthusiasts worldwide are openly nervous about its chances. NASA itself has dubbed the descent “seven minutes of terror” (see NASA’s web video by that name at www.jpl.nasa.gov/video/index.cfm?id=1090) - the time it will take to reach the ground after slamming into the atmosphere at 13,000 mph.
So why all the white-knuckles and nail-biting? It’s about the landing plan. The simpler airbag-cushioned landings used by the 1996 Pathfinder, and the rovers Spirit and Opportunity in 2004, won’t work for the large and heavy MSL. Scott Gold, in the L.A. Times, compared the scheme to get Curiosity safely down to something that Wile E. Coyote might have designed to catch the Road Runner.
Mostly, it’s that “sky crane” thing assigned the task of lowering the rover its final 66 feet to the ground. This ungainly contraption performs the last of a long list of complex tasks - which includes deploying parachutes, jettisoning the heat-shield, using radar to map the ground for landing navigation, and firing rockets to further slow the descent (parachutes alone are not adequate in Mars’ thin atmosphere) - all of this meant to place the rover “wheels down” and intact on its new world.
Even as the wheels touch ground, one more thing has to happen before the rover is free: pyrotechnics must simultaneously sever each cable so the sky crane can fly them and itself about 500 feet, leaving the rover out of harm’s way.
The sky crane system will get its first full test on Mars, since Martian conditions could not be replicated here. With human guidance 15 light-minutes away, every step is automated. (One light-minute equals 11,176,944 miles.) The landing will be carried “live,” but by the time we receive the data and see the descent images, the whole thing will be over. This amazing and scary scenario is by itself enough to keep mission scientists lying awake at night, but there’s plenty more to fuel their anxieties.
For one, Mars has an earned reputation for “eating” spacecraft for lunch. Of the 17 missions (including Curiosity) launched specifically to probe its mysteries by NASA and other space agencies since the Viking orbiters and landers in 1976, at least 10 ended in failure - most recently, last year’s Russian Fobos-Grunt which, with its Chinese Yinghuo-1 orbiter, failed to leave Earth orbit. Before Viking, the record is even more dismal.
So MSL is a one-shot deal, with no doubles like the twin Viking landers and the Spirit and Opportunity rovers. All its eggs are in one basket. And what’s at stake? Curiosity could help determine whether Mars is, or ever was, capable of supporting life as we know it.
Radiation levels and trace gases in the air will be measured, as will the geologic and chemical makeup of rocks and soil. The idea is to cross off all the things that obviously aren’t life, and then look carefully at what’s left. For example, if organic molecules are found, are they kinds that can be made by processes that aren’t life, or not?
But Curiosity is not designed - to the chagrin of many - to look directly for life. Why? A lot has to do with the phenomenally successful twin Viking lander missions of 1976, and the confusing, inconclusive results from the carefully designed experiments they carried meant to answer the life question.
Curiosity will help scientists design better detection instruments in the future, but many grow impatient with the baby-steps approach. I can’t say I disagree. An answer in my lifetime would be nice.
The absence of dedicated instruments does not mean Curiosity is incapable of finding life; it would just have to be stunningly obvious - like large fossils. Curiosity’s microscope is powerful enough to detect only giant microbes, which are the least likely to survive the harsh radiation near the surface. If only we could look deeper underground.
There is another issue: If Curiosity were to spot a microbe wiggling through its microscope’s field, or its scanners detected biomolecules, it’s not clear if we could determine whether this was Martian life, or something Curiosity brought along itself.
After touchdown, we’ll take a first look at the surrounding terrain, but better pictures will come the next day from atop the rover’s 7-foot mast. The Mastcam’s hi-res color 3D images and movies are eagerly awaited. Views of Gale Crater’s central mountain, the 3-mile high Mount Sharp - taller than California’s Mount Whitney, the tallest mountain in the lower 48 U.S. states - should be incredible.
Touchdown is expected around 1:31 a.m. on Aug. 6. NASA announced last week that the Odyssey orbiter was back online and ready to relay the landing “live.” Odyssey’s trajectory, which was disrupted by a July 11 malfunction, has been corrected so that live coverage can be expected. Without that we would have faced an uncomfortable delay before finding out whether the rover made it.
Curiosity will join NASA’s solar-powered Opportunity Mars rover, which has survived nearly eight years of brutal Martian conditions. Mission planners hope to start driving Curiosity in the middle of September, its nuclear power ensuring at least one Mars-year (equal to two Earth-years) of exploration, with hopes for more.
Many worry how a failure would affect further public support and funding of the space agency that has led the world in space exploration for half a century. Could Curiosity be the last U.S.-built Mars rover due to cuts to NASA planetary science budget?
Odyssey, which arrived at Mars in 2001, is the oldest working spacecraft there. As the only one capable of relaying the MSL telemetry directly back to Earth during the descent, it now has the honor of allowing us to witness Mars’ newest arrival.
Finally, a tribute to former astronaut Sally Ride, who died at 61 years young last week: Your level headed and continuing efforts to employ space exploration as an inspirational tool in the education of coming generations should surpass your roles as America’s first woman in space, as well as a member of the panels investigating both the Challenger and Columbia shuttle disasters. My hat’s off to you. May your mark be lasting.
So ride on, Sally Ride.
Follow ever-changing celestial highlights in the Skywatch section of the Weather Almanac in the Daily Republican and Sunday Republican.
Patrick Rowan has written Skywatch for The Republican since 1987 and has been a Weather Almanac contributor since the mid 1990s. A native of Long Island, Rowan graduated from Northampton High School, studied astronomy at the University of Massachusetts-Amherst in the ¤’70s and was a research assistant for the Five College Radio Astronomy Observatory. From 1981 to 1994, Rowan worked at the Springfield Science Museum’s Seymour Planetarium, most of that time as planetarium manager. Rowan lives in the Florence section of Northampton with his wife, Clara, and cat, Luna.