MISSION TO MARS
DECEMBER 4, 1996
A NASA Mars probe was launched Wednesday from Cape Canaveral. Called Pathfinder it left on a Delta 2 rocket complete with airbags for the July 4th landing and a roving science lab that will pick up data from the surface of the "red planet." Jeffrey Kaye reports on what NASA scientists hope to achieve from this, the second in a series of unmanned missions to earth's distant neighbor.
SPOKESMAN: Zero and liftoff.
A RealAudio version of this NewsHour segment is available.
August 7, 1996
Kwame Holman reports on a Martian meteorite that has the scientific community buzzing.
July 10, 1996
Jeffrey Kaye looks at the moons of Jupiter
The Johnson Space Center
Check out recent pictures of Mars.
JEFFREY KAYE: Early this morning, a Delta Two rocket blasted off from Cape Canaveral, Florida. It is carrying Pathfinder, NASA's second spacecraft in a month destined for Mars. This rocket's red glare will end in fireworks July 4th, when Pathfinder is scheduled to make a fiery descent through the Martian atmosphere and land on the red planet.
DONNA SHIRLEY: On Independence Day 1997, Earth is invading Mars.
JEFFREY KAYE: Donna Shirley is manager of the Mars exploration program at the Jet Propulsion Lab, JPL, in Pasadena. She says this is one of a fleet of missions planned for the next decade.
DONNA SHIRLEY, Manager, Mars Exploration Program: Every 26 months, we're going to fly to Mars, with either one or two--with either one or two spacecraft, we'll fly to Mars every 26 months.
SPOKESMAN: And we have lift-off of NASA's Mars Global Surveyor.
JEFFREY KAYE: Last month's launch of the Global Surveyor marked the beginning of a new NASA initiative to explore Mars. That spacecraft is expected to take 10 months to reach the planet. Its job is to orbit Mars for two years, measure the atmosphere, and chart its surface.
DONNA SHIRLEY: It carries a camera that is going to be mapping the whole planet every day so that we can see how the weather changes and what changes are going on on Mars. And there is another camera which takes high resolution pictures of the surface so that you would be able to see something about the size of a car.
JEFFREY KAYE: Pathfinder, the spacecraft launched today, is designed to execute a spectacular series of maneuvers. After takeoff, the spacecraft will jettison its launch rockets. In July, as it dives into the Martian atmosphere, friction will create a display of fireworks, and a parachute will pop out to slow the spacecraft down. Initially, the landing posed a dilemma for engineers. How could Pathfinder survive a crash onto the Martian surface? Flight software engineer Steven Stolper described the solution.
STEVEN STOLPER, Flight Software Engineer: The engineers were up late one night, thinking about it. And they were watching TV, and on TV, they saw a car commercial. And what would save someone from a crash in a car commercial? An air bag. Right before we land and hit the surface, we inflate four giant air bags, one on each side of the lander. So we're not only going to hit, we're going to bounce. And our first bounce should take us over an eight-story building. So we're going to bounce, and we're going to roll. We're going to tumble. And eventually, we're going to come to rest on the surface of Mars.
JEFFREY KAYE: At that point, the air bags deflate to reveal the pyramid-shaped lander. The lander must open properly to release a remote-controlled rover designed to wheel around and explore the Martian surface. Stolper built a model of the Lander to study another potential problem. What if the thing lands the wrong way?
STEVEN STOLPER: But if we land on the wrong side, what we do is the computer selects the down-most petal, and it chooses to open the down-most petal--and once we reach our base petal, we open up like a flower.
DONNA SHIRLEY: And the rover is sitting on one petal, and there's a camera in the middle, and so the camera goes up on a stalk and takes pictures, in stereo, and 12 different colors. Those pictures are sent by the lander back to the Earth. The rover stands up and roams around, and that's how we do the mission. Brian Cooper, who's the operator, puts on three-dimensional goggles, looks into the scene, and can see, you know, how far away the rocks are, for example.
JEFFREY KAYE: He has a driver's seat view of what the lander is seeing.
DONNA SHIRLEY: He has a driver's seat view. Exactly. And the scientists do too, because that same data is there for the scientists. So the scientists will all be crowded around a screen, arguing with each other about what rock to send the rover to, and once they decide, they say, “Okay, Brian, we want that rock.” And then Brian takes a mouse and with an icon of the rover, a little picture of the rover, and he puts it on that rock, and he goes “click” with the mouse, so she goes off in the direction--she knows where she is--so she goes off in the direction from where she is to where the rock is.
JEFFREY KAYE: The 25-pound rover is powered by solar energy and batteries. It is a science lab on six wheels, equipped with a camera and a unit called an Alpha Proton X-Ray Spectrometer, that's a sort of a high-tech nose, designed to analyze the composition of Martian rocks. JPL scientists have been test driving a twin version of the rover. It has been programmed to move cautiously and climb rocks. When it gets to Mars, scientists will program the rover once a day. Because of a 10-minute delay in getting a signal to Mars, the rover has to have a mind of its own.
DONNA SHIRLEY: The rover is about as smart as a bug and, in fact, uses a control scheme based on insect behavior. But if the operator were to watch the rover in real time, and the rover were heading for a cliff, the operator would say, “Don't fall over the cliff,” because it would be 10 minutes before he could say, “No, no, don't do that.” So that's why the rover has to be able to take care of itself, understand that those are obstacles, go around the obstacles, and if she can't get around the obstacles, she stops and calls home and says: “Help, I can't get around this obstacle.”
JEFFREY KAYE: At another JPL test site, engineers have set up a “Mars Room”--a large sand box with a mockup of the lander and rover.
JEFFREY KAYE: And what's the role of the lander?
ROB MANNING, Flight Systems Engineer: The lander is our eyes and our main communications mechanism for--between Pasadena and Mars. All commands that we send to Mars go to the lander. The lander then communicates directly with the rover with a small antenna.
JEFFREY KAYE: The lander also has a set of instruments designed to send Martian weather reports back to Earth. The Mars missions are designed to pick up where other projects left off--but at a fraction of the cost. Under NASA's new philosophy of “better, faster, cheaper,” the current Mars missions cost $500 million--12 percent of the Viking spacecraft which went to Mars in 1976. Viking sent back images of volcanoes, dust storms, polar regions, canyons, and valleys the size of the United States, as well as evidence of lake beds and streams. In six years, Viking transmitted more than 55,000 photographs, to the delight of scientists. But the Viking program was an exception. Of the 25 U.S. and Russian missions to Mars since 1960, two thirds ended in failure, so still, the mystery remains.
DONNA SHIRLEY: Did life ever start on Mars, because it is the only other place in the solar system that we think had a good chance of life starting. Now, we know that life is not running around easy to find, because the Viking missions did not find any, and they were looking very hard. And we know there are no little green people running around. But we don't know whether there are bacteria inside the rocks.
JEFFREY KAYE: Speculation about life on Mars has been fanned by recent discoveries of organic traces in meteorites that apparently fell to Earth from Mars.
ROB MANNING: By knowing what the composition of the rocks is, we can infer their origins. And, in fact, we're landing in an area where there's rocks from all different areas from the highlands of Mars, because we're landing in the outflow channel of a large flood. With all these varieties of rocks, we can infer a bit about the history of Mars, and in particular answer the key questions-- how long water was on the surface of Mars. Of course, that addresses the more key question of was there life on Mars early on, and, if so, how long did it last?
JEFFREY KAYE: And that's what the big mystery is, right--what happened to the water?
ROB MANNING: Exactly.
JEFFREY KAYE: Understanding what happened to the water could not only provide clues about past life on Mars but about future life on Earth.
DONNA SHIRLEY: Mars and the Earth kind of grew up together, like siblings, and Venus too. So here's three rocky planets, and they all evolved out of the solar disk at about the same time. And then somehow or other, Mars got real cold, lost most of its atmosphere, Venus got real hot, and got more atmosphere than you ever want. And Earth stayed just right. Now why is that? So we go to Mars partly to learn about Mars, but also to understand the Earth and our place in the universe.
STEVEN STOLPER: Now the other thing you were talking about, the water--as someone who might want to live there one day, where that water is is very important to me, if we ever decide to go to Mars as a people, as a nation.
JEFFREY KAYE: Are you really serious about that? I mean, maybe you have plans to move. I don't know if you do. I don't know if I do. I mean, is this what this is all pointing towards, do you think, colonizing Mars?
ROBB MANNING: My view is that there--I am just curious. I want to know where Mars--it's Mars' early history--I want to know how Mars' evolution affects--affected our evolution.
STEVEN STOLPER: Okay. I differ from Rob there. I see myself as pragmatic. We've learned a lot about Earth. We have problems here on Earth. We're running up against resource constraints, environmental questions, population questions, and also, a little bit of adventure. I would like to go to Mars, if it's at all possible, in my lifetime. And I'm not willing to rule that out as a wish.
DONNA SHIRLEY: I think the fascination with Mars, and the pioneering spirit about people who want to explore Mars, is very analogous to the pioneering spirit of the--that took us to the American West and the exploration of the world. And that's our near-term horizon, that's our near-term frontier, is Mars. And we're going to send our robots there until we decide it's safe enough and interesting enough to send people there.
JEFFREY KAYE: Shirley says the U.S. is discussing future joint missions to Mars with European, Russian, and Japanese partners.