Universe Today

Image credit: UMich
One of the big problems with space travel is that one cannot over pack.

Suppose astronauts reach Mars. How do they explore the planet if they cannot weigh down the vessel with fuel for excursions?

A team of undergraduate aerospace engineering students at the University of Michigan is doing research to help astronauts make fuel once they get to Mars, and the results could bring scientists one step closer to manned or extended rover trips to the planet.

Their research proposal won the five-student team a highly competitive trip to NASA’s Johnson Space Center in Houston to participate in the Reduced Gravity Student Flight Opportunities Program.

In Houston, the students conducted zero-gravity experiments using iodine as a catalyst to burn magnesium. Magnesium is a metal found on Mars that can be harvested for fuel?fossil fuels don’t burn on Mars because of the planet’s carbon dioxide (CO2) atmosphere, but metals do burn in a CO2 atmosphere.

The idea for the students’ experiments evolved from previous research done by Margaret Wooldridge, an associate professor in mechanical engineering and the team’s adviser. Wooldridge’s research showed that while magnesium is a promising fuel source, burning magnesium alone?without a catalyst such as iodine?has several challenges. Preliminary results from the student experiments showed that using iodine as a catalyst helped make the magnesium burn better, said Arianne Liepa, aerospace engineering undergrad and team member.

The experiments also showed that using the iodine, magnesium, CO2 system worked even better in a microgravity environment. “That bodes well for a power source on Mars where the gravity is approximately one-third that of Earth,” Wooldridge said.

The students?Greg Hukill, Arianne Liepa, Travis Palmer, Carlos Perez and Christy Schroeder?who conducted the experiments over a nine-day period in March, flew on a specially modified Boeing KC 135A turbojet transport. The plane flies parabolic arcs to produce weightless periods of 20 to 25 seconds at the apex of the arc.

Original Source: University of Michigan News Release

Image credit: NASA/JPL
As both rovers approach their third month resident on Mars, the mission planners have returned to Earth time. Both rover teams look to make rapid progress toward distant hills, with a possible second September extension continuing with any remaining mission science.

JPL Mars Program Office Head, Dr. Firouz Naderi, indicated that with this week’s first mission extension, even more may be planned. Currently slated for September 13 as the next mission milestone, such an ambitious science schedule would give the rovers 250 Sols on the planet’s surface. “This is all bonus science,” said Naderi. “After the solar conjunction (alignment between Mars, Earth and the Sun) around September 13th, we would probably propose to NASA for a second extension.” During a solar conjunction, explained Naderi, the Sun blocks line-of-sight views between the Earth tracking and martian surface operations for seven to ten days. “The Sun gets in the way,” said Naderi, explaining that during the lead-up to September 13th, both rovers will be given a deserved weeklong respite, followed by what many hope will be further healthy science operations to follow.

For the rest of 2004, the engineering and science team will look to stretch more life out of their six-wheeled laboratories. The primary constraints on further operations will be thermal, power, and dust accumulation from seasonal change and road weathering. Mission manager, Matt Wallace, explained previously that both rovers were healthy: “We try to keep our finger on the pulse of vehicle health, looking for signals or markers of subtle changes and trends. Except for environmental changes (power, thermal, optical opacity and dust accumulation), there is no wear and tear on subsystems.”

At Gusev crater, the extended Spirit mission will look to traverse towards Columbia Hills. At Meridiani Planum, the extended Opportunity mission will rack up long drives across the flat plains towards Endurance Crater. At full speed, the rovers can clock from 50 to 100 meters per Sol.

Naderi noted that the switch of mission personnel back to Earth time has been a welcome transition. For future missions, he said, the consensus for long-term operations will likely move away from following Mars’ sunrise and sunset times. One problem other than the late and early on-site shifts at JPL has been the inability to sleep at consistent times because the approximately 39 minute longer martian day continues always to push and rotate schedules. Dr. Ray Arvidson, deputy Principal Investigator and Washington University, St. Louis professor of geology, compared the hectic three months on Mars time to jetlag when a transatlantic traveler returns from Europe. “It takes three to four days to get back to Earth time,” said Arvidson.

One other benefit, according to Arvidson, is that since mission science is planned for Spirit and Opportunity on opposite sides of Mars, now that both teams work on the same clock, they will be able to simplify coordination and strategic science targets. There are people on the other rover tream, said Arvidson, “who I haven’t seen for three months except in the parking lot.”

Spirit’s mission manager for surface operations, Jennifer Trosper, noted that on her first day back on Earth time (last Monday), she was pleased not to come into work at 1 A.M. But as she was getting ready for bed that night proved to be exactly when she was called back to JPL–to troubleshoot why the Spirit rover had not responded to a ‘beep’ signal sent from Earth around midnight.

Trosper said that new flight software will be a major priority for the coming days. She explained that while there were risks associated with any commands that change the rovers’ state, the software has been thoroughly pre-tested. The first upload of flight software was not loaded until only one month before launch. The critical descent and landing software was not loaded on the spacecraft until nearly three months after launch, while the probe was well on its way to Mars.

In detail, Trosper noted, their plan will feature first the transfer of software command files for six hours a day over 4 days of direct communication from Earth to the high-gain antenna on both rovers. “When we get all the files on-board, then we build the flight software (locally on the rovers). When that is complete, the rovers go to sleep for 15 minutes, waking up with a new system.” The Spirit rover was the first to encounter file overloads after 18 days of file storage, and at one point could not send any data to Earth except that its system clock had shifted to the year 2053. Later changes in software succeeded in rejoining the rovers with JPL’s command center.

Arvidson highlighted a few near-term science objectives as further investigation on Spirit continues to calibrate the dusty martian skies. By pointing the rover’s panoramic camera towards the sky, while overhead satellites look down, scientist hope to remove the masking influence of dust. Spirit completed these coordinated observations with the thermal emission spectrometer instrument on NASA’s Mars Global Surveyor orbiter. The observations involved miniature thermal emission spectrometer pre-flight, simultaneous, and post-flight sky and ground measurements. Spirit also collected a panoramic camera opacity observation.

Opportunity continues to surprise scientists as it found another outcrop similar to what was first seen in its landing hole at Eagle Crater. But this time, the outcrop is on the edge of a trough in the middle of the plains. “This outcrop looks texturally like Eagle Crater,” and current plans are to spend several days probing what appears to be bedrock. Bedrock is of interest if it has preserved a layered timeline of rock deposit. Since this deposit also has ripples, scientists hope to discover whether its chemistry “speaks to water,” said Arvidson. “The trough is probably a fracture, we don’t know how young?”

While there is a “strong desire to get another 100 meter drive, to get to Endurance Crater,” said Arvidson, “the hope is to spend a few Sols here.”

Original Source: NASA/JPL News Release

Image credit: UC Berkeley
The same cutting-edge technology that speeded sequencing of the human genome could, by the end of the decade, tell us once and for all whether life ever existed on Mars, according to a University of California, Berkeley, chemist.

Richard Mathies, UC Berkeley professor of chemistry and developer of the first capillary electrophoresis arrays and new energy transfer fluorescent dye labels – both used in today’s DNA sequencers – is at work on an instrument that would use these technologies to probe Mars dust for evidence of life-based amino acids, the building blocks of proteins.

Graduate student Alison Skelley at the Rock Garden, one of the sites in Chile’s Atacama desert where researchers sampled soil for amino acids in preparation for sending an instrument to Mars to look for signs of life. The ruins of the city of Yunguy are in the background. (Photo courtesy Richard Mathies lab/UC Berkeley)

With two development grants from NASA totaling nearly $2.4 million, he and team members from the Jet Propulsion Laboratory (JPL) at the California Institute of Technology and UC San Diego’s Scripps Institution of Oceanography hope to build a Mars Organic Analyzer to fly aboard NASA’s roving, robotic Mars Science Laboratory mission and/or the European Space Agency’s ExoMars mission, both scheduled for launch in 2009. The ExoMars proposal is in collaboration with Pascale Ehrenfreund, associate professor of astrochemistry at the University of Leiden in The Netherlands.

The Mars Organic Analyzer, dubbed MOA, looks not only for the chemical signature of amino acids, but tests for a critical characteristic of life-based amino acids: They’re all left handed. Amino acids can be made by physical processes in space – they’re often found in meteorites – but they’re about equally left- and right-handed. If amino acids on Mars have a preference for left-handed over right-handed amino acids, or vice versa, they could only have come from some life form on the planet, Mathies said.

“We feel that measuring homochirality – a prevalence of one type of handedness over another – would be absolute proof of life,” said Mathies, a UC Berkeley member of the California Institute for Quantitative Biomedical Research (QB3) . “That’s why we focused on this type of experiment. If we go to Mars and find amino acids but don’t measure their chirality, we’re going to feel very foolish. Our instrument can do it.”

The MOA is one of a variety of instruments under development with NASA funding to look for the presence of organic molecules on Mars, with final proposals for the 2009 mission due in mid-July. Mathies and colleagues Jeffrey Bada of Scripps and Frank Grunthaner of JPL, who plan to submit the only proposal that tests for amino acid handedness, have put the analyzer to the test and shown that it works. The details of their proposal are now on the Web at http://astrobiology.berkeley.edu.

In February, Grunthaner and UC Berkeley graduate student Alison Skelley traveled to the Atacama desert of Chile to see if the amino acid detector – called the Mars Organic Detector, or MOD – could find amino acids in the driest region of the planet. The MOD easily succeeded. However, because the second half of the experiment – the “lab-on-a-chip” that tests for amino acid handedness – had not yet been married to the MOD, the researchers brought the samples back to UC Berkeley for that part of the test. Skelley has now successfully finished these experiments demonstrating the compatibility of the lab-on-a-chip system with the MOD.

“If you can’t detect life in the Yungay region of the Atacama Desert, you have no business going to Mars,” Mathies said, referring to the desert region in Chile where the crew stayed and conducted some of their tests.

Mathies, who 12 years ago developed the first capillary array electrophoresis separators marketed by Amersham Biosciences in their fast DNA sequencers, is confident that his group’s improvements to the technology utilized in the genome project will feed perfectly into the Mars exploration projects.

“With the kind of microfluidic technology we’ve developed and our capability to make arrays of in situ analyzers that conduct very simple experiments relatively inexpensively, we don’t need to have people on Mars to perform valuable analyses,” he said. “So far, we’ve shown this system can detect life in a fingerprint, and that we can do a complete analysis in the field. We’re really excited about the future possibilities.”

Bada, a marine chemist, is the exobiologist on the team, having developed nearly a dozen years ago a novel way to test for amino acids, amines (the degradation products of amino acids) and polycyclic aromatic hydrocarbons, organic compounds common in the universe. That experiment, MOD, was selected for a 2003 mission to Mars that was scrapped when the Mars Polar Lander crashed in 1999.

Since then, Bada has teamed with Mathies to develop a more ambitious instrument that combines an improved MOD with the new technology for identifying and testing the chirality of the amino acids detected.

The ultimate goal is to find proof of life on Mars. The Viking landers in the 1970s unsuccessfully tested for organic molecules on Mars, but their sensitivity was so low that they would have failed to detect life even if there were a million bacteria per gram of soil, Bada said. Now that the NASA rovers Spirit and Opportunity have almost certainly shown that standing water once existed on the surface, the aim is to find organic molecules.

Bada’s MOD is designed to heat Martian soil samples and, in the low pressures at the surface, vaporize any organic molecules that may be present. The vapor then condenses onto a cold finger, a trap cooled to Mars’ ambient nighttime temperature, approximately 100 degrees below zero Fahrenheit. The cold finger is coated with fluorescamine dye tracers that bind only to amino acids, so that any fluorescent signal indicates that amino acids or amines are present.

“Right now, we are able to detect one trillionth of a gram of amino acids in a gram of soil, which is a million times better than Viking,” Bada said.
The added capillary electrophoresis system sips the condensed fluid off the cold finger and siphons it to a lab-on-a-chip with built-in pumps and valves that route the fluid past chemicals that help identify the amino acids and check for handedness or chirality.

“MOD is a first stage interrogation where the sample is examined for the presence of any fluorescent species including amino acids,” Skelley said. “Then, the capillary electrophoresis instrument does the second stage analysis, where we actually resolve those different species and can tell what they are. The two instruments are designed to complement and build on one another.”

“Rich has taken this experiment into the next dimension. We really have a system that works,” Bada said. “When I started thinking about tests for chirality and first talked to Rich, we had conceptual ideas, but nothing that was actually functioning. He has taken it to the point where we have an honest-to-God portable instrument.”

Amino acids, the building blocks of proteins, can exist in two mirror-image forms, designated L (levo) for left-handed and D (dextro) for right-handed. All proteins on Earth are composed of amino acids of the L type, allowing a chain of them to fold up nicely into a compact protein.

As Mathies describes it, the test for chirality takes advantage of the fact that left-handed amino acids fit more snugly into a left-handed chemical “mitt” and right-handed amino acids into a right-handed mitt. If both left- and right-handed amino acids travel down a thin capillary tube lined with left-handed mitts, the left-handed ones will travel more slowly because they slip into the mitts along the way. It’s like a left-handed politician working a crowd, he said. She’ll move more slowly the more left-handed people in the crowd, because those are the only people she will shake hands with. In this case, the left-handed mitt is a chemical called cyclodextrin.

Different amino acids – there are 20 different kinds used by humans – also travel down the tube at different rates, which allows partial identification of those present.

“After amino acids are detected by MOD, the labeled amino acid solution is pumped down into microfluidics and crudely separated by charge,” Mathies said. “The mobility of the amino acids tells us something about charge and size and, when cyclodextrins are present, whether we have a racemic mixture, that is, an equal amount of left- and right-handed amino acids. If we do, the amino acids could be non-biological. But if we see a chiral excess, we know the amino acids have to be biological in origin.”

The state-of-the-art chip designed and built by Skelley consists of channels etched by photolithographic techniques and a microfluidic pumping system sandwiched into a four-layer disk four inches in diameter, with the layers connected by drilled channels. The tiny microfabricated valves and pumps are created from two glass layers with a flexible polymer (PDMS or polydimethylsiloxane) membrane in between, moved up and down using a pressure or vacuum source. UC Berkeley physical chemist James Scherer, who designed the capillary electrophoresis instrument, also developed a sensitive fluorescence detector that quickly reads the pattern on the chip.

One of the team’s current NASA grants is for development of a next-generation Microfabricated Organic Laboratory, or MOL, to fly to Mars, Jupiter’s moon Europa or perhaps a comet and conduct even more elaborate chemical tests in search of a more complete set of organic molecules, including nucleic acids, the structural units of DNA. For now, however, the goal is an instrument ready by 2009 to go beyond the current experiments aboard the Mars 2003 rovers and look for amino acids.

“You have to remember, so far we have not detected any organic material on Mars, so that would be a tremendous step forward,” Bada said. “In the hunt for life, there are two requirements: water and organic compounds. With the recent findings of the Mars rovers that suggests that water is present, the remaining unknown is organic compounds. That’s why we are focusing on this.

“The Mars Organic Analyzer is a very powerful experiment, and our great hope is to find not only amino acids, but amino acids that look like they could come from some sort of living entity.”

Original Source: Berkeley News Release