Mars... it may be the most likely place in our Solar System outside of Earth to have ever harbored life. And it is undoubtedly the nearest. That has made our red sister planet the target of ever more intense exploration.
In July of 1997 a small wheeled robot, "Sojourner," spent a few weeks sampling the rocks near its landing site on Mars. That amazing achievement and those of Pathfinders recently-launched successor Mars 98 will no doubt go down in history as triumphs of robotic planetary exploration, but NASA engineers are planning another more daring feat: a mission to bring back pieces of the red planet.
The Mars Sample Return missions quietly went from "proposed" to "future" status late last month (although stn2s visit and story soon prompted a press release from NASAs Jet Propulsion Laboratory). Rob Manning, the Chief Engineer for Pathfinder, has been named the new missions manager. "Our intent is in the year 2008 for a sample to come back land safely on earth," Manning says. "And well be able to send it to scientists all over the world to analyze and understand what Mars was like oh so long ago, back when Mars and Earth looked so much alike. Thats the mystery."
In spite of his pride in current and previous Mars missions, Manning longs for hard evidence. "The small, hi-tech sensors are great but they dont even shake a stick to what you can do in an earth-based laboratory. And for years and years people have just been dying to get their hands on a real Mars sample. Well, it turns out we have a couple of samples from Mars. The famous metoer found in Antarctica, ALH-84001."
Whether the composition and odd structure of the Allen Hills meteor are evidence of past life on Mars could still be an object of intense study and debate by the time Manning gets his hands on a "real sample." The famous rock "most certainly came from Mars," Manning says. "The question isÉ has that rock been modified by being on earth for thousands of years, being in orbit around the sun for maybe millions of yearsÉ WhatŐs more, we donŐt have a context for it. We dont know about how it was formed, where it formed, what kind of a rock was it in. Was it from under the surface, was from the highlands?"
"The only way to really get a good handle about Mars itselfits geology, its environment, its ancient history, and more importantly what environments may been present early in Mars history that may have been conducive for lifethe only way to do that is to bring a pristine set of samples from Mars to Earth."
Manning toys with model rovers in his office on JPLs campus in Pasadena, as he explains what will likely be his mission of a lifetime. He describes the new missions, to be launched in 2003 and 2005, as "robotic versions of Apollo," the manned missions to the moon. And, ScienCentral News learned, the mechanical actors that will carry out the mission are already being designed and built.
In JPLs Planetary Robotics lab, a prototype rover fondly christened "FIDO" traverses a terrain of crushed garnets which mimic the surface and colorof Mars. Paul Schenker, Technical Supervisor of JPLs Mechanical Robotics Group, makes the introduction. "Thats the Field Integrated Design and Operations rover and its an advanced technology prototype. This rover will be smarter, faster, longer than the ones that have explored the red planet to date," says Schenker. (FIDO is so new, you wont find him in a news release yet, either. But hes scheduled for his first field-testing in the desert near Silver Lake, CA in April 1999.)
In fact, FIDO is twice as long, twice as high, and four times heavier than the tiny Sojourner. And while Sojourner snuggled and sniffed only near-by rocks within view of Pathfinders camera, the sample return rover based on FIDO will carry a camera on-board, atop a 6-foot mast, so that it can travel far from its lander.
That will enable it to seek out and collect a diversity of samples. "The scientists want to look at not any particular rock but at very particular rocks, they want to pick out the ones that have high priority or high likelihood of having something interesting about them," Mechanical Robotics Group leader Eric Baumgartner says.
The sample return rover will employ a small drill, as well as a robotic arm much like the one now flying on Mars Polar Lander. While the Apollo astronauts simply "stuffed a bag," as Manning puts it, the Mars Sample rover will spend about three months collecting some 30 core samples from locations selected by scientists. It will seal them in special tubes, carry them back to the lander, and transfer them to an orbiter capsule in the nose-cone of a small rocket.
Then, unlike the Apollo astronauts, the astro-"bot" wont be coming home. Manning describes the rocket as much like a missile, with just enough power to put a "grapefruit-sized cannister" into Mars orbit. "The rocket tips up, fires and sends this grapefruit with the samples in it and there it sits in a nice safe spot. Putting things in Mars orbit is a very good place to store things. Its very well-understood, it doesnt have these extreme temperature changes night and day. Thats where it will stay for two and a half years. It has a little radio in it, going beep beep beep, doing its little phoning home, waiting for someone to catch it."
"We then do the same thing with another rocket (in 2005) and another grapefruit." But, accompanying the 2005 mission will be a French-made rocket that seeks out and captures one or both of the capsules and returns them to Earth, where theyll land in some big, safe place, such as the US Air Force Testing Facility near Salt Lake City, Utah.
The capsules will be handled with the highest levels of biohazard containment just in case they contain traces of Martian life. Manning says one of the biggest challenges of his job will be not only "going clean"avoiding cross-contamination from both Earth to Mars and from Mars to Earthbut also, communicating the precautions to the public in an environmental impact assessment.
Because Mars current environment is so hostile to lifethe planet has no ozone layer"quite frankly were very skeptical there will be anything alive in the rock first of all, and that theres even fossils of life... the odds of getting those are fabulously small," Manning says. But because scientists cant say for sure the odds arent zero, NASA will adhere to guidelines issued by a special task force of the National Academy of Sciences Space Science Board.
But Manning says his biggest challenge of all will be to deliver the samples on time and on-budget. Manning says theyll be relatively cheap, "like Pathfinder, not like Viking." His guesstimated goal is three times the cost of Pathfinder, excluding the French contribution. Pathfinders total cost, including launch vehicle and mission operations, was $280 million.