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Gay Yee Hill: It's been a busy year here at NASA's Jet Propulsion Laboratory and let's bring you up to date on some of our current and future missions.
JPL's Mars Phoenix Lander is on course for touchdown on Martian soil May 25th. If successful, it'll be the first spacecraft to land in the Martian arctic and the first to collect and analyze water ice from the surface of another planet. But before that, Phoenix will experience a harrowing seven minutes as it hurls through the Martian atmosphere to what we hope is a soft landing. The success rate of landing on Mars is only about 50 percent, which is why landing day for Phoenix is a guaranteed nail-biter.
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Ben Cichy: Phoenix is the first Mars Scout mission. It's the first mission that's going to try to land near the north pole of Mars. And it's the first mission that's actually going to go try and reach out and touch water on the surface of another planet.
Lynn Craig: Where there tends to be water, at least on Earth, there tends to be life and it's potentially a place where life could have existed on the planet in the past.
Erik Bailey: The main purpose of EDL is to take a spacecraft that is traveling at 12,500 miles an hour and bring it to a screeching halt in a soft way, in a very short amount of time.
Ben Cichy: We enter the Martian atmosphere, we're 70 miles above the surface of Mars, and our lander is safely tucked inside what we call an aeroshell.
Erik Bailey: It looks kind of like an ice cream cone, more or less.
Ben Cichy: And on the front of it is this heat shield, this saucer-looking thing, that has about a half inch of essentially what's cork on the front of it, which is our heat shield. Now, this is really special cork, and this cork is what's going to protect us from the violent atmospheric entry that we're about to experience.
Rob Grover: Friction really starts to build up on the spacecraft, and we use the friction, when it's flying through the atmosphere, to our advantage to slow us down.
Ben Cichy: From this point we're going to decelerate from 12,500 miles an hour down to 900 miles an hour.
Erik Bailey: The outside can get almost as hot as the surface of the sun. The temperature of the heat shield will reach 2600 degrees Fahrenheit. But the inside doesn't get very hot. It probably gets about room temperature.
Richard Kornfeld: There is this window of opportunity within which we can deploy the parachute.
Erik Bailey: If we fire the chute too early, the parachute itself could fail. The fabric in the stitching could pull apart, and that would be bad.
Ben Cichy: In the first fifteen seconds after we deploy the parachute, we'll decelerate from 900 miles an hour to a relatively slow 250 miles an hour. We no longer need the heat shield to protect us from the force of atmospheric entry, so we jettison the heat shield, exposing for the first time our lander to the atmosphere of Mars.
Lynn Craig: After the heat shield has been jettisoned and the legs are deployed, the next step is to have the radar system begin to detect how far Phoenix really is from the ground.
Ben Cichy: We've lost 99 percent of our entry velocity, so we're 99 percent of the way to where we want to be, but that last 1 percent, as it always seems to be, is the tricky part.
Erik Bailey: Now the spacecraft actually has to decide when it's going to get rid of its parachute.
Ben Cichy: We separate from the lander going 125 miles an hour at roughly a kilometer above the surface of Mars, 3200 feet. That's like taking two Empire State Buildings and stacking them on top of one another.
Erik Bailey: That's when we separate from the back shell and we're now in freefall. It's a very scary moment. A lot has to happen in a very short amount of time.
Lynn Craig: So it's in a freefall, but it's also trying to use all of its actuators to make sure that it's in the right position to land.
Erik Bailey:And then it has to light up its engines, right itself, and then slowly slow itself down, and touch down on the ground safely.
Ben Cichy : EDL is this immense technically challenging problem about getting a spacecraft that's hurdling through deep space and using all of its bag of tricks to somehow figure out how to get it down to the surface of Mars at zero miles an hour. It's an immensely exciting and challenging problem.
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Gay Yee Hill: Meanwhile, what's happening with the Mars rovers Spirit and Opportunity? Well, the resilient rovers are still operating four years after landing on Mars for what was to be a three-month mission. Truth is, scary moments this past year have threatened to end the mission. Severe dust storms darkened the skies, making it difficult to get energy through the solar panels, and both rovers are showing their age. Opportunity's arm is giving it trouble. Spirit's right front wheel has to be dragged along. But our engineers have developed ways to keep them going. In fact, if Spirit's broken wheel hadn't been churning up the soil, scientists wouldn't have spotted silica and salts associated with water. So, the rovers persevere. Spirit is wintering on a north-facing slope, trying to get as much sun as possible on its dust-covered solar panels, and Opportunity is inside the magnificent Victoria Crater.
From above, the Mars Reconnaissance Orbiter is also taking amazing high-resolution pictures, including the first ever image of active avalanches. These were taken near the Red Planet's north pole. And from the poles of Mars to Earth poles, NASA and international space agencies are collaborating to study our polar regions. Observations by satellites as well as on the ground have shown that the huge expanses of Greenland and Antarctica are melting away in response to climate warming. Ice melt raises sea level, and the impact on coastal areas could be devastating.
JPL's Ocean Surface Topography Mission, Jason 2, will be an ocean watcher. It'll monitor sea level rise, ocean circulation, and climate change.
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Parag Vaze:As most people know, the majority of the Earth is covered by the oceans. They store a majority of the heat that we get, and in that respect interact with the climate.
Shannon Brown: The ocean is a big sink for heat. It can absorb heat from the atmosphere, so if we continue to warm the atmosphere through increasing carbon dioxide or other factors, the ocean will absorb that heat and store it, and it can store up to 80 percent of that heat. But the question is, will it keep doing that in the future? The Ocean Surface Topography Mission is important because it provides a view of the changing climate. It monitors the consequences of global climate change and global warming by monitoring sea level rise.
Lee-Lueng Fu: Half the world's population lives within 100 kilometers from the coast. The sea level is rising at 3 million meters per year. The ice sheet of Antarctica and Greenland each has the capacity of rising sea level by meters. That could inundate most of Florida and inundate Manhattan.
Shannon Brown: It's measuring the height of the ocean surface to a few inches from 800 miles above the surface of the Earth. Imagine my hand here as the spacecraft and this ball as the pulse of energy, radar energy that it sends to the surface. What it does is it measures the amount of time for it to come back. If the ocean surface is lower, which is represented by this lower step here, it takes a longer amount of time to come back than if it were higher.
The radar altimeter sends a pulse of microwave energy down to the surface and measures the amount of time it takes to get back. It continues the measurements that were started in 1992 by Topex/Poseidon, and continued with the Jason 1 satellite, and now we have the OSTM, which is going to continue this record into the future and will help us answer questions like is sea level rise going to accelerate.
Parag Vaze: OSTM is going to be able to provide us some of the key information to understanding and predicting and tracking hurricanes. It's going to be able to provide us the same kind of information for oil rigs, for shipping, for fisheries management, and those are some of the very practical applications besides just the long-term monitoring of climate, to really give us day-to-day applications where we'll be able to improve our weather forecasts.
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Gay Vee Hill: The Ocean Surface Topography Mission is scheduled for launch from Vandenberg Air Force Base on June 15th. Six months later, another satellite, the Orbiting Carbon Observatory, is scheduled for launch. OCO will measure our planet's carbon dioxide levels from space.
Let's turn now to a spacecraft that's been in orbit around the ringed planet for nearly four years. The Cassini Mission has made stunning discoveries about the Saturn system. The spacecraft found evidence of water ice geysers jetting from the surface of the moon in Enceladus, which feeds particles into Saturn's outermost ring. On the closest pass yet, Cassini gave us a roller coaster view of the bumpy ridge around mysterious Iapetus, and revealed that Saturn's orange moon, Titan, has earthlike features such as lakes, clouds and mountains. It has hundreds of times more liquid hydrocarbons than all the known oil and natural gas reserves on Earth. Discoveries like that are why NASA extended Cassini's tour another two years, and Cassini tour designers worked at breakneck speed to come up with its new travel plan.
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NASA has added two years to the Cassini mission to Saturn. Where to go? What to see? To prepare for this extended journey, engineers had to chart some tricky maneuvers trying to fulfill the wish lists of two hundred scientists.
Nathan Strange: The spacecraft's going. You have a locomotive speeding on the track; they haven't built the railway yet. We're up front laying track. It's a lot like if you're in AAA and you go get a trip tick on the counter. Someone sits there with a map and draws out with a highlighter where you're going and plans out the trip with you. So the scientists are on one side of the counter telling us what they want to see, and then we're with the map, mapping out a route and saying, "How's this? How's that?"
Gay Yee Hill: For the last year and a half, Cassini tour designers have been working at breakneck speed on plans for an extended mission.
John Smith:It's not what you call a low-stress job by any means.
Brent Buffington: They essentially lay down on the table what they want, as far as science goals and science objectives. We come back. We take that off for a couple of months, you know, apply astrodynamics.
Nathan Strange: The people that want to look at the rings want to be up high and look at the rings. The other people want to be down in the same plane with the rings, where they can visit all the other moons. That's a huge tug-of-war.
Jonathan Lunine: So what the tour designers have to do is to take all of these different inputs from hundreds of scientists and say, "We have to observe this. We want to look at that," and put that together into a very compact new tour of tour years.
Conference speaker 1: This tour has 26 Titan flybys. It has two high northern ground tracks.
Conference speaker 2: The last Titan flyby is over here, so this is where it reaches the ring point, so it kind of moves over a little bit.
John Smith: We show a variety of different tours that are kind of in different flavors. One makes the rings people a little bit more happier than the moons people.
Conference speaker 3: Okay, goals this PSG, obviously for us, we think it's select the final tour.
John Smith: They rated the tours in terms of red, unacceptable; yellow, acceptable; and green, acceptable.
Conference speaker 4: But it sounds like 6H9 and 8 should either both be red or both be yellow.
John Smith: Now all the candidates are out there and they've got to pick one.
Conference speaker 4: 6H9, three greens, a lime, and a red.
John Smith: And in the end it was shades of green.
Conference speaker 4: We will continue this in executive session.
Gay Yee Hill: The science team leaders made the final decision.
John Smith: When the tour was called, this kind of hard-to-pronounce PF6H9, that's the name of this hybrid tour.
Gay Yee Hill: Cassini's travel itinerary includes sixty additional orbits of Saturn, studies of the rings, the magnetosphere, twenty-six flybys of Titan, and close encounters with other exotic moons.
Brent Buffington: That's real gratifying that it was a hybrid tour, that it took kind of the best of a lot of different tours that we had been designing.
Gay Yee Hill: The Cassini Mission to Saturn has revolutionized our knowledge of the ringed planet, and the best may be yet to come.
Jonathan Lunine: To be able to fly through space in a complex place full of moons and rings and dust and so on, and to be able to navigate this space in such a way as to give Cassini a chance to make all the discoveries that the scientists on the mission would like to see happen, I don't think of it as a wish list; I think of it as a list of potential new discoveries that will be in the textbooks forever, and these guys are the ones who will make it happen.
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Gay Yee Hill: One reason why we explore is to get answers to the questions "Where did we come from? Are we alone?" Trying to get the answers takes a bit of detective work, but scientists are beginning to get some clues. NASA's Galaxy Evolution Explorer discovered that a well-known star has a gigantic comet-like tail that's seeding future generations of planets and stars.
Water is an essential ingredient for life as we know it, and astronomers using NASA's Spitzer Infrared Space Telescope discovered water vapor for the first time on a scorching hot gas planet outside of our solar system. We've known of water beneath Jupiter's moon, Europa, and now there's evidence of an underground ocean beneath the crust of Saturn's moon, Titan.
What keeps scientists exploring the universe? They're looking for life in all the right places.
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Max Coleman: We're not looking for aliens. We're not even looking for fossils. We'll be looking for bacteria or signs of bacteria, and the reason for that is because for most of the Earth's history, they've been the predominant form of life. The chances are it may be different from life on Earth, and therefore what we have to look for is if it's doing the same things that life does on Earth.
Leslie Tamppari: Water is a necessary component for life as we know it, so when we think about trying to understand life on other planets, one of our strategies is to understand the water.
Max Coleman: We're focusing on Mars because Mars in its early history may have been a lot warmer and wetter than it is now.
Leslie Tamppari: It looks like there used to be flowing liquid water on the surface of Mars, but today there isn't any liquid water that we can find, or if there is any, it's very infrequent. We want to detect organics because organics are the building blocks for life. Organics are molecules that contain carbon, and we know that carbon is the central element that makes up our bodies and it makes up life. So both Phoenix and the Mars Science Laboratory will search for organics on Mars.
Phoenix is the next Mars Lander mission. When we land on Mars, we're going to land in the north polar region. That's about equivalent to about Alaska latitude on the Earth, or mid-Greenland. Our job is to land and dig down and sample the soils and ice that we'll encounter in that region of Mars.
Max Coleman: Mars Science Laboratory will have sophisticated instruments which will be able to look at the mineralogy in much more detail, but also looking at minerals which either were formed by organisms, living organisms, or show signs that living organisms were around when they were formed. But we're not only focusing on Mars; there are other places in the solar system which may have subsurface water.
Beyond the solar system there are people who are looking at the planets which go around distant stars, trying to analyze their atmosphere. There's no silver bullet. We've got to take all the possible approaches, or at least a large number of them, and put all the bits together to see where to look and what to find. Looking for life outside the Earth, to find out whether we're alone or not—hey, what better job could there be?
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Gay Yee Hill: Now you're up to date with JPL highlights. All these videos, plus podcasts and more, can be found on JPL.NASA.GOV. Interested in high-def? Just click on the HD download link. Sign up for our email news and RSS feeds, and you'll be up to date all year 'round. That's for stopping by.
