Mars-bound spacecraft fine turns course for landing [Phoenix]

PASADENA, Calif. -- NASA engineers have adjusted the flight path of the Phoenix Mars Lander, setting the spacecraft on course for its May 25 landing on the Red Planet.

"This is our first trajectory maneuver targeting a specific location in the northern polar region of Mars," said Brian Portock, chief of the Phoenix navigation team at NASA's Jet Propulsion Laboratory in Pasadena, Calif. The mission's two prior trajectory maneuvers, made last August and October, adjusted the flight path of Phoenix to intersect with Mars.

NASA has conditionally approved a landing site in a broad, flat valley informally called "Green Valley." A final decision will be made after NASA's Mars Reconnaissance Orbiter takes additional images of the area this month.

The orbiter's High Resolution Imaging Science Experiment camera has taken more than three dozen images of the area. Analysis of those images prompted the Phoenix team to shift the center of the landing target 13 kilometers (8 miles) southeastward, away from slightly rockier patches to the northwest. Navigators used that new center for planning today's maneuver.

The landing area is an ellipse about 62 miles by about 12 miles (100 kilometers by 20 kilometers). Researchers have mapped more than five million rocks in and around that ellipse, each big enough to end the mission if hit by the spacecraft during landing. Knowing where to avoid the rockier areas, the team has selected a scientifically exciting target that also offers the best chances for the spacecraft to set itself down safely onto the Martian surface.

"Our landing area has the largest concentration of ice on Mars outside of the polar caps. If you want to search for a habitable zone in the arctic permafrost, then this is the place to go," said Peter Smith, principal investigator for the mission, at the University of Arizona, Tucson.

Phoenix will dig to an ice-rich layer expected to lie within arm's reach of the surface. It will analyze the water and soil for evidence about climate cycles and investigate whether the environment there has been favorable for microbial life.

"We have never before had so much information about a Mars site prior to landing," said Ray Arvidson of Washington University in St. Louis. Arvidson is chairman of the Phoenix landing-site working group and has worked on Mars landings since the first successful Viking landers in 1976.

"The environmental risks at landing -- rocks and slopes -- represent the most significant threat to a successful mission. There's always a chance that we'll roll snake eyes, but we have identified an area that is very flat and relatively free of large boulders," said JPL's David Spencer, Phoenix deputy project manager and co-chair of the landing site working group.

Today's trajectory adjustment began by pivoting Phoenix 145 degrees to orient and then fire spacecraft thrusters for about 35 seconds, then pivoting Phoenix back to point its main antenna toward Earth. The mission has three more planned opportunities for maneuvers before May 25 to further refine the trajectory for a safe landing at the desired location.

In the final seven minutes of its flight on May 25, Phoenix must perform a challenging series of actions to safely decelerate from nearly 21,000 kilometers per hour (13,000 mph). The spacecraft will release a parachute and then use pulse thrusters at approximately 914 meters (3,000 feet) from the surface to slow to about 8 kilometers per hour (5 mph) and land on three legs. "Landing on Mars is extremely challenging. In fact, not since the 1970s have we had a successful powered landing on this unforgiving planet. There's no guarantee of success, but we are doing everything we can to mitigate the risks," said Doug McCuistion, director of NASA's Mars Exploration Program at NASA Headquarters in Washington.

The Phoenix mission is led by Peter Smith of the University of Arizona, Tucson, with project management at JPL and development partnership at Lockheed Martin, Denver. International contributions are provided by the Canadian Space Agency; the University of Neuchatel, Switzerland; the universities of Copenhagen and Aarhus, Denmark; the Max Planck Institute, Germany; and the Finnish Meteorological Institute.

They are tossing around metric and English units in this article. They sure don’t need another metric mix-up, although that was not JPL IIRC. The article below is heavy on the Search for Life, but then it is from Astrobiology magazine:

http://www.marsdaily.com/reports/Visting_Mars_Again_And_Again_999.html

Visting Mars, Again And Again

by Staff Writers
for Astrobiology Magazine
Moffett Field CA (SPX) Apr 08, 2008

Mars is preparing for an invasion from Earth. The rovers Spirit and Opportunity are still traveling across the surface of the Red Planet, but NASA and the European Space Agency are planning to send more missions over the next few years. First up is the Mars Phoenix lander. Launched last year, this mission is due to arrive near the Martian north pole on May 25.

The lander won’t be able to move around like the rovers — instead, it will stay in one place, scraping away at water ice just beneath the surface in a search for the organic compounds that are thought to be necessary for life.

NASA’s next rover mission is the Mars Science Laboratory, or MSL. A much larger rover than the ones currently on Mars, MSL will collect soil and rock samples and analyze them for organics. The planned launch for MSL is Fall of 2009, with an expected arrival in October 2010.

The European Space Agency also has plans for a rover. Called ExoMars, the projected launch date for this mission is 2013, with arrival in 2014. The ExoMars rover will have a drill that can dig deep into the subsurface, allowing scientists to search for evidence of water and organics.

Astrobiology Magazine’s Helen Matsos recently sat down to talk with Michael Meyer, lead scientist for NASA’s Mars Exploration Program, and Luann Becker, a University of California, Santa Barbara geochemist who has been developing the Mars Organic Molecule Analyzer (MOMA) that will fly on the ExoMars mission.

Astrobiology Magazine (AM): Could you tell me about MOMA and the role will it play in the search for life on Mars?

Luann Becker (LB): MOMA is a mass spectrometer that will look for organic matter in the near-subsurface of Mars. It’s our attempt to improve on the Gas Chromatograph-Mass Spectrometer, or GCMS, from the 1976 Mars Viking mission. We took what we thought was a perfectly good approach to the search for life, added new technology, and hoped this new design would be a better way to evaluate whether life ever occurred on Mars.

MOMA is like a Star Trek tricorder, because we can use it to cover the full gambit of measurements that will answer the question of life. We’ve combined the GCMS that is currently flying on several missions — including Rosetta that is now headed to a comet — and added on our part of the instrument. Ours is the more technically challenging part, and I think it’s got the extra oomph that we need to evaluate the entire suite of possible organics that could be present on Mars.

We know there has to be refractory organic matter on Mars. Mars has been constantly bombarded by meteoritic debris and interstellar dust particles, so there’s been a lot of opportunity for the planet to become enriched with organic matter. We expect organics to at least be in the regolith, maybe only a few meters down.

If we do identify some organic component, we can compare it to what has been found by other instruments that try to find specific organics. Then we’ll be able to address the difficult question of whether something interesting is there, and that will strengthen the case for sample return, to pick up some rocks and bring them back to Earth.

Michael Meyer (MM): It’s interesting that nobody has measured organics on the surface of Mars. It was a big surprise when Viking’s GCMS did not find organics. We think we’re now smart enough to look for organics, and we’re starting our search with Phoenix. Phoenix has an instrument called TEGA, the Thermal Evolved Gas Analyzer.

It will heat up a sample and volatilize any organics that are there — they’ll come off as carbon dioxide vapor, and the instrument will measure that. Although it might be difficult to characterize what organics might be there, we’ll at least know whether or not there are organics. That’s a big first step.

The mission after Phoenix, the Mars Science Laboratory, or MSL, is going to send a GCMS that will look for a broad range of organic material. But it’s not going to be able to look for the entire suite of organic matter that might be on Mars. To compensate for that, MSL will do a derivatization - take a known molecule and extract organic matter out of the soil with it, and then run it through the instrument.

AM: How might these missions help clarify lingering doubts about the Viking results?

MM: Part of the controversy was with Viking’s Labeled Release Experiment. The concept was that if we added organics and water to the Martian soil, all the Martian organisms in that soil would go to town eating the organic matter. The organics would in the process be broken down into carbon dioxide gas, and we could measure that.

The experiment worked, except according to the GCMS there was no organic matter to start with. Because there’s no organic matter to start with, the presumption is that there could not be any organisms there.

Now, the prevailing theory is that the breakdown of the added organic matter was due to the highly oxidizing nature of the surface of Mars. Mars doesn’t have much of a protective atmosphere or a magnetic field, so the surface is irradiated by ultraviolet light. It’s as if somebody poured peroxide over the surface of Mars and let it sit there — anything organic that fell on that surface would be converted to CO2. Still, even though that’s the prevailing theory, we don’t know if that’s actually true.

LB: Viking was an excellent experiment if you think about the strategy behind it: going to Mars and heating a sample, something we do everyday in our laboratory. We thought the surface would be full of carbon and organic matter. The big surprise was how oxidizing and harsh the surface environment really was. Had we considered that, we may have tried a different approach.

For example, we might have tried to go deeper into the subsurface. We were in a wonderful spot with Viking to detect any possible organics, because water ice was probably near the surface. If we had been able to do more, maybe we could have answered that question about organics.

Certainly we would have had more compelling results, and then we could have been able to continue at that time with our Mars program. But instead we got ambiguous results - something might be there, but it might not be there. Anytime you get an ambiguous result, that’s considered a non-result.

I still marvel at how successful Viking truly was. After all, had Viking not been measuring other components like the atmosphere, we would never have known that we had Martian meteorites. Trapped gas within those meteorites matched the Martian atmospheric composition determined by Viking. So in a way, Viking is still playing an important role in why we are going back to Mars.

AM: With all the missions that are going to Mars, will we be able to collect enough data to finally give a conclusive answer as to whether Mars has life?

MM: The short answer is, yes. The missions are going to be seeking answers to a couple of different questions. Question one is, “What organics are there?” Question two is, “Where are the organics?” That’s the tough one. We’re talking about a planet where much of its surface is over four billion years old, and organics from its early days have been sitting around for an extended period of time. If any organics from this time period remain, they would have to be in a protected environment such as ice or beneath the surface.

So there are different places we can look where organics may have been preserved from early in Mars’ history. A side story is that, just like Earth, Mars is getting organics from space all the time. And so the question is, “Where is all that organic material going?” We need to find places where a micrometeorite can land and then get buried or protected from the extreme environment.

LB: Location, location, location... that really is key. We’ll have to use every bit of information we get from the satellites currently flying. The Mars Reconnaissance Orbiter has sophisticated high resolution cameras that are providing detailed images of the Martian surface, and we can use those to find the best targets. Where can we go that will give us the most robust results?

I think picking the best locations will be almost as important as any instrument we can come up with. The Phoenix mission is going to be interesting, because it’s landing in one of my favorite locations for looking for organics.

AM: If Phoenix were to get some sort of positive indication, is that enough to say that we’ve detected life on Mars? Or will that just be the first step?

MM: Everybody would be happy if we find organics, because then at least we’ve proved they’re there, as we think they ought to be. Then the big debate would be, “What are they really?” In terms of instrumentation, there’s a degree of how well they can characterize the organics that we find. If we find very degraded organics - like kerogen or coal -it would difficult to say whether that organic matter came from space or if it was from a biological process on Mars.

We are sending missions to three different places. Phoenix is going to dig into the ice near the north pole. Mars Science Laboratory has a little drill, so it’s going to go to wherever there’s exposed bedrock and rocks lying around. ExoMars has a big drill, so it’s going to go deeper down into the surface.

Even if they landed on the same spot, they would be sampling different things. So it’s the range of places that we’re going to look, and then the range in the sophistication of the instrumentation that will make a difference in terms of how well we can characterize the results.

Life tends to use the same molecules over and over again. For instance, if we find chiral compounds — all left handed or all right handed molecules — the only process we know that has those is life. And we could say, “Slam-dunk, we win, we found life on Mars!” Or we could find something old that contained only certain classes of compounds. That would make us suspicious because we’re lacking the whole kitchen sink, and there would be a great debate.

LB: I think too that an exciting potential outcome of this particular suite of missions is to learn something about our own origin of life. For years we’ve been debating about how life evolved on our own planet some 4 billion years ago. The regolith of Mars is very old, and Mars was probably doing the same thing as Earth back then. It had all the same ingredients — it had water, it had an atmosphere, and it potentially had sedimentary rocks.

Wouldn’t it be remarkable if we get that piece of the puzzle that has been completely erased from the Earth? To discover whatever it was that led to the DNA and RNA world, which is so unique and absolutely prolific with respect to life. Wouldn’t it be remarkable if we found that precursor molecule that we think was so important to getting life started? Now that would be an important and very exciting result!

This is a lunar atmosphere satellite. Who knew the moon has an atmosphere worth a satellite.

http://www.moondaily.com/reports/NASA_Sets_Sights_On_Lunar_Dust_Exploration_Mission_999.html

NASA Sets Sights On Lunar Dust Exploration Mission

by Staff Writers
Washington DC (SPX) Apr 10, 2008

NASA is preparing to send a small spacecraft to the moon in 2011 to assess the lunar atmosphere and the nature of dust lofted above the surface. Called the Lunar Atmosphere and Dust Environment Explorer (LADEE), the mission will launch before the agency’s moon exploration activities accelerate during the next decade.

LADEE will gather detailed information about conditions near the surface and environmental influences on lunar dust. A thorough understanding of these influences will help researchers understand how future exploration may shape the lunar environment and how the environment may affect future explorers.

“LADEE represents a low-cost approach to science missions, enabling faster science return and more frequent missions,” said Ames Director S. Pete Worden. “These measurements will provide scientific insight into the lunar environment, and give our explorers a clearer understanding of what they’ll be up against as they set up the first outpost and begin the process of settling the solar system.”

LADEE is a cooperative effort with NASA’s Ames Research Center at Moffett Field, Calif., Goddard Space Flight Center in Greenbelt, Md., and Marshall Space Flight Center in Huntsville, Ala. The total cost of the spacecraft is expected to be approximately $80 million.

Ames will manage the mission, build the spacecraft and perform mission operations. Goddard will perform environmental testing and launch vehicle integration. The mission will be established within Marshall’s newly created Lunar Science Program Office. Marshall will draw upon experience gained from managing a larger suite of low-cost, small satellite missions through NASA’s Discovery and New Frontiers Program.

LADEE will fly to the moon as a secondary payload on the Discovery mission called Gravity Recovery and Interior Laboratory (GRAIL), which is designed to take ultra-precise gravity field measurements of the moon. Current plans call for the GRAIL and LADEE spacecraft to launch together on a Delta II rocket and separate after they are on a lunar trajectory.

LADEE will take approximately four months to travel to the moon, then undergo a month-long checkout phase and begin 100 days of science operations.

LADEE is one of many activities to support lunar exploration planned by NASA’s Science Mission Directorate in Washington. Last year, NASA also established a lunar science institute at Ames. Research teams will address current topics in basic lunar science and possible astronomical, solar and Earth science investigations that could be performed from the moon.

In addition, NASA is preparing for scientific investigations following the planned launch later this year of the Lunar Reconnaissance Orbiter (LRO). After a 30-year hiatus, LRO represents NASA’s first step toward returning humans to the moon.

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