CAPE CANAVERAL, Fla. – A NASA probe bound for Mars’ arctic circle is in good health, mission managers said following its Aug. 4 predawn launch.
The Phoenix Mars Lander is precisely on target for its 679 million-kilometer trip to the red planet following its liftoff from the Cape Canaveral Air Force Station, Fla., aboard a United Launch Alliance Delta 2 rocket. The three-stage booster is due to land May 25, 2008, on the flat arctic plains of Vastitas Borealis, near Mars’ north pole, where it is expected to dig into and sample the region’s icy soil with its 2.4-meter robotic arm.
“It was the most beautiful thing I’ve seen,” Peter Smith, Phoenix principle investigator at the University of Arizona, said of the liftoff. “This cloud turned into what looked like wings and a beak and a long tail and looked amazingly just like a phoenix bird, the message to me was: Phoenix bird has risen! And it has. We’re on our way to Mars.”
The launch was so precise that Phoenix was able to conserve about 10 kilograms of precious propellant, which will add some maneuvering flexibility once the probe prepares for its descent to Mars’ surface next year.
The launch had been delayed a day due to bad weather during rocket fueling.
The $420 million Phoenix mission is built on the ashes of NASA’s canceled Mars Surveyor 2001 Lander and the ill-fated Mars Polar Lander, which crashed during landing in December 1999. Much of the 350-kilogram probe and its seven science instrument packages are built from hardware based on or recycled from those two missions, mission managers have said.
“I started working on this spacecraft in 1997, so it’s incredibly gratifying to watch it finally go up,” said Tim Gasparrini, deputy program manager for the Phoenix mission at Lockheed-Martin. “It’s not often that you get a second chance in life.”
Phoenix coasted through space between a series of engine burns before final spacecraft separation about 90 minutes after liftoff. The spacecraft took longer than mission managers expected to send a signal back to Earth, but eventually notified mission control of its good launch trajectory and fully operational solar panels.
“It seemed like an eternity,” NASA launch director Chuck Dovale said. “We weren’t sure that Phoenix would phone home, and she did and we’re happy.”
“The cruise to Mars will be about nine and a half months,” Ed Sedivy, Phoenix spacecraft program manager for Lockheed Martin, which built the Mars probe for NASA, said before liftoff. “And then we’ll go through the descent, entry and landing, which is the big enchilada for the mission.”
Following its nine-month journey, Phoenix will attempt a soft touchdown on the red planet. After plunging through the martian atmosphere behind its protective aeroshell, the lander will deploy a parachute to slow its descent, extending three landing legs and firing a set of pulse rockets to make a smooth touchdown on the surface.
If successful, the landing will mark the first soft touchdown on Mars since NASA’s massive Viking lander missions in the 1970s.
Managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California, the Phoenix mission is expected to last at least 90 Martian days, or sols.
Polar science
Researchers used imagery from NASA’s Mars Reconnaissance Orbiter and other spacecraft to ensure that Phoenix’s landing site was relatively clear of rocks, steep slopes or other conditions that could pose a hazard to the spacecraft. The landing site is at a latitude on Mars similar to that of northern Alaska or Iceland on Earth, mission managers said.
In addition to its backhoe-like robotic arm, Phoenix is equipped with a series of science tools to taste, sniff and peer at martian soil and ice. The probe will not hunt for evidence of life itself, but rather will look for the conditions in which microbes or other organisms could exist, mission scientists said.
Tiny ovens and a wet chemistry laboratory mounted to Phoenix’s upper surface, or deck, will scan soil and ice samples for signs of organic molecules and compounds – one ingredient useful for life – while cameras and microscopes image the samples.
Each oven can be used only once and will cook just a pinch of martian soil – about 30 microliters – and then analyze the leftovers.
“When the oven is heated … it gives off vapor just like cookie dough in your kitchen,” said William Boyton the oven instrument’s lead scientist at the University of Arizona. “And we use that to see what’s going on.”
Phoenix also is equipped to serve as the first polar weather station on Mars. The lander’s 1.2-meter meteorology mast gives the probe a total height of just over 2.2 meters and carries a series of heat sensors to measure atmospheric temperature at different heights. A small cylinder tethered to the top of the mast will indicate wind direction, Phoenix researchers said.
A laser detection and ranging, or lidar, tool will beam light into the martian sky, then measure the amount reflected to track atmospheric particles and clouds.
“I’m excited about finding Earth-like clouds at Mars,” Deborah Bass, NASA’s deputy Phoenix project scientist at JPL, told reporters Aug. 1.
While Mars researchers are targeting a 90-Martian day mission for Phoenix, they don’t expect the lander to last as long as NASA’s hardy rovers Spirit and Opportunity, which are currently hunkered down to weather a massive dust storm in their fourth year of an initial three-month mission.
“Once winter approaches, we will be immersed in solid carbon dioxide ice,” Smith said. “It will certainly not survive that kind of winter.”
But before Phoenix can study Mars, the probe must first reach the red planet, which has proven to be a challenge in the past. More than half of all Mars-bound missions have failed to date, NASA has said.
“As smart as we like to think we are, we’re not clearly as smart as we need to be,” Barry Goldstein, Phoenix project manager at JPL, said before launch, calling Mars a spacecraft eater. “It really is a difficult job. No matter how many times we land successfully, it will never be routine.”
DAVE MOSHER contributed to this article
