Posted on by Fraser Cain

Help Support Universe Today

I’ve had several generous offers from readers wondering how they could donate money to help me maintain Universe Today; which, as you know is pretty much a labour of love. I’ve felt a little uncomfortable about the idea, but a few of you have been very persistent. 🙂

So, I’ve gone ahead and set up with Paypal so you can donate money to Universe Today. If you feel that this website and newsletter are of value to you, and you want to contribute, just click this link which will take you to a form where you can donate money with your credit card. Universe Today has always, and will always be free. This is totally voluntary, and I leave it up to you to contribute only if it’s something you want to do. Knowing me, I’ll probably just use additional funds to hire some additional writers.

Thanks for all your support and kindness, I really appreciate it.

Fraser Cain
Publisher
Universe Today

P.S. People have also been wanting updated pictures of Chloe and Logan. Here’s Chloe with her favorite alien brainsucker hat.

Posted on by Fraser Cain

Cassini Sees Clumps in Saturn’s Rings

Image credit: NASA/JPL
Clumps seemingly embedded within Saturn’s narrow, outermost F ring can be seen in these two Cassini narrow angle camera images taken on Feb. 23, 2004 from a distance of 62.9 million kilometers (39 million miles). The images were taken nearly two hours apart using the camera’s broadband green filter, centered at 568 nanometers. Image scale is 377 kilometers (234 miles) per pixel.

The core of the F ring is about 50 kilometers (31 miles) wide, and from Cassini’s current distance, is not fully resolvable. Contrast has been greatly enhanced, and the images have been magnified, to aid visibility of the F Ring and the clump features.

The images show clumps as they revolve about the planet. Like all particles in Saturn’s ring system, these features orbit the planet in the same direction in which the planet rotates. This direction is clockwise as seen from Cassini’s southern vantage point below the ring plane. Two clumps in particular, one of them extended, can be seen in the upper part of the F ring in the image on the left, and in the lower part of the ring in the image on the right. Other knot-like irregularities in the ring’s brightness can also be seen in the right hand image.

Clumps such as these were first seen when the two Voyager spacecraft flew past Saturn in 1980 and 1981. It is not certain what causes these features, though several theories have been proposed, including meteoroid bombardment and inter-particle collisions in the F ring.

The Voyager data suggest that while the clumps change very little and can be tracked as they orbit for 30 days or more, no identified clump survived from the Voyager 1 flyby to the Voyager 2 flyby nine months later. Thus, scientists have only a rough idea of the lifetime of clumps in Saturn’s rings – a mystery that Cassini may help to answer.

The small dot at center right in the second image is one of Saturn’s small moons, Janus (181 kilometers, 112 miles across). Janus was discovered by ground-based astronomers in 1966, and was first resolved by the Voyager 1 spacecraft in 1980. The moon shares almost the same orbit with another small satellite, Epimetheus. Janus and Epimetheus, both thought to consist mostly of porous ices, play a role in maintaining the outer edge of Saturn’s A ring.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For information about the Cassini-Huygens mission, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Spirit Sees the Earth

Image credit: NASA/JPL
Consistently highly rated among those memorable ‘money-shots’ from the current Mars’ surface exploration is a view looking back towards the Earth. On Thursday, the Spirit rover team released the banner image showing the Earth as a tiny gray dot in the martian sky near the horizon.

The history of such views backwards towards the home planet, Terra Firma, have captivated the imagination for a generation of astronomers. This glimpse from the surface of another planet offers an unrivalled perspective that stretches beyond just seeing our home as one of many planets, or the only pale blue dot in our solar system.

As Carl Sagan’s widow, Anne Druyan , described this perspective image to Astrobiology Magazine, such earth views make “us look at this tiny planet, at the pale blue dot, and to see it in its real context, in its actual circumstances, in its true tininess. I don’t know anyone who’s able to really see that one-pixel Earth and not feel like they want to protect the Earth; that we have much more in common with each other than we’re likely to have with anyone anywhere else.”

The evocative phrase describing the Earth as a ‘pale blue dot’ was coined by Carl Sagan after seeing our planet as a single pixel. The view was taken from the departing Voyager spacecraft. The entire earth could be encompassed as a flicker of light. The first image of Earth ever taken from another planet that actually shows our home as a planetary disk was captured by the Mars Orbital Camera on May 8th.

One question that might be answerable from such a world-view is could a scientist on Mars identify from such a perspective that the Earth harbored life. In 1993, a team of researchers inspired by Carl Sagan, used an Earth fly-by of the Galileo spacecraft on its way to Jupiter to catch a glimpse of how the Earth might appear from afar. For astrobiologists, Sagan’s results were surprising.

Rather than seeing the Earth as an obvious candidate for life, the Galileo pictures gave surprisingly few clues of the biological potential of our own planet.

From afar, how Galileo missed the obvious signs of terrestrial life as we would have expected to see them, was at first disconcerting to the scientific community, because future missions aim to observe more distant extrasolar planets and detect what would be visible in the spectra–the ‘pale blue dot’ scenario.

One answer may lie in the fact that the spacecraft made its observations while still quite close to the Earth.

“The spectrograph was designed to look at small areas of Jupiter, so the field of view of the spectrograph was quite small,” said Nick Woolf of Arizona, in earlier discussions with the Astrobiology Magazine.

“Also, since the surface brightness of Jupiter [the Gaileo’s intended visual target] is far less than the Earth, the spectrograph detectors saturated except when the spectrograph was pointed at the darkest area of Earth – a cloud-free section of sea,” Woolf noted. The cloud-free sea is considered very dark relative to the dominance of bright clouds in a global picture of Earth. Thus it should come as no surprise that Galileo was successful in only imaging a relatively dark and lifeless planet, mainly because its design was not intended to look at Earth, but to probe Jupiter instead.

A spectroscope that might detect infrared or visible light looking back on Earth or outwards to other planets might focus mainly on four gases that are found in Earth’s atmosphere and linked to life:

* Water vapor A baseline sign, indicating the presence of liquid water, a requirement of known life.
* Carbon dioxide Can be created by biological and non-biological processes. Because it is necessary for photosynthesis, it would indicate the possible presence of green plants.
* Methane Considered suggestive of life, it also can be made both by biological and non-biological processes.
* Molecular oxygen (O2) – or its proxy, ozone (O3). The most reliable indicator of the presence of life, but still not conclusive.

Unless molecular oxygen in the atmosphere is constantly replenished by photosynthesis, it is quickly consumed in chemical reactions, in the atmosphere, on land and in seawater. So the presence of a large amount of oxygen in an extrasolar planet’s atmosphere would be a sign that it might host an ecosystem like present-day Earth’s.

An additional oxygen-related biosignature is the possibility of detecting green plants that make oxygen. Chlorophyll reflects near-infrared light very strongly, a phenomenon known as the “red edge” because the light is just beyond the range of colors human eyes can see. (If humans could see the red edge, plants would look red instead of green.) Near-infrared cameras would have no trouble picking up this distinctive signal.

Not only are earth-views aesthetically interesting, while offering a chance to test remote sensing scenarios, the rovers more practically depend on a daily sky view to navigate. The rover design does not possess any intrinsic way of knowing its orientation as north or south for instance, because Mars doesn’t offer a strong magnetic field that might typically give a compass reading. So scientists point the rover’s mobile panoramic camera to do a sun sighting daily, which also provides today’s orientation. Navigating by stars on Mars is also possible although the rovers’ solar power arrays typically are put into electronic sleep-modes at night to conserve power.

Spirit imaged stars on March 11, 2004, after it awoke during the martian night for a communication session with NASA’s Mars Global Surveyor orbiter. This image is an eight-second exposure. Longer exposures were also taken. The images tested the capabilities of the rover for night-sky observations. Scientists will use the results to aid planning for possible future astronomical observations from Mars.

Original Source: NASA Astrobiology Magazine

Posted on by Fraser Cain

Santa Ana Winds Stimulate Marine Environment

Image credit: NASA/JPL
Southern California’s legendary Santa Ana winds wreak havoc every year, creating hot, dry conditions and fire hazards. Despite their often-destructive nature, a study of the “Devil Winds,” conducted using data from NASA’s Quick Scatterometer (Quikscat) spacecraft and its SeaWinds instrument shows the winds have some positive benefits.

“These strong winds, which blow from the land out into the ocean, cause cold water to rise from the bottom of the ocean to the top, bringing with it many nutrients that ultimately benefit local fisheries,” said Dr. Timothy Liu, a senior research scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., and Quikscat project scientist. Santa Ana consequences include vortices of cold water and high concentrations of chlorophyll 400 to 1,000 kilometers (248 to 621 miles) offshore.

Liu and Dr. Hua Hu of the California Institute of Technology, Pasadena, in a paper published last year in Geophysical Research Letters, revealed satellite observations of the Santa Ana effects on the ocean during three windy days in February 2003. According to the findings, Quikscat was able to identify the fine features of the coastal Santa Ana wind jets. It identified location, strength and extent, which other weather prediction products lack the resolution to consistently show, and moored ocean buoys lack sufficient coverage to fully represent.

Quikscat’s high-resolution images of air-sea interaction were used to measure wind forces on the ocean. Other satellites and instruments, like the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the Advanced Very High Resolution Radiometer, onboard a National Oceanic and Atmospheric Administration polar orbiting weather satellite, were used to measure the temperature and biological production of the ocean surface, which respond to the wind.

The latter instrument showed sea surface temperatures dropped four degrees Celsius (seven degrees Fahrenheit) during the February 2003 Santa Anas. That was a sign that upwelling had occurred, meaning, deep cold water moved up to the ocean surface bringing nutrients. Images from SeaWiFS confirmed the increased biological productivity by measuring chlorophyll concentrations in the surface water. It went from negligible, in the absence of winds, to very active biological activity (more than 1.5 milligrams per cubic meter) in the presence of the winds.

“There really is no other system that can monitor Santa Ana winds over the entire oceanic region,” Liu said. “Scatterometers such as Quikscat have a large enough field of view and high enough resolution to easily identify the details of coastal winds, which can affect the transportation, ecology and economy of Southern California.”

High pressure develops inland when cold air is trapped over the mountains, driving the dry, hot and dusty Santa Anas (also called Santanas and Devil’s Breath) at high speeds toward the coast. The winds, occurring in fall, winter and spring, can reach 113 kilometers (70 miles) per hour. They happen at any time of day and usually reach peak strength in December. Telltale signs on the coast include good visibility inland, unusually low humidity and an approaching dark brown dust cloud.

The Quikscat satellite, launched in June 1999, operates in a Sun- synchronous, 800-kilometer (497-mile) near-polar orbit. It circles Earth every 100 minutes and takes approximately 400,000 daily measurements over 93 percent of the planet’s surface. It passes over Southern California about twice a day, skipping a day every three or four days.

Quikscat is part of an integrated Earth observation system managed by NASA’s Office of Earth Science. The NASA enterprise is dedicated to understanding the Earth as an integrated system and applying Earth System Science to improve prediction of climate, weather, and natural hazards using the unique vantage point of space.

For information about NASA programs on the Internet, visit:

http://www.nasa.gov.

For information about Quikscat and SeaWinds on the Internet, visit:

http://winds.jpl.nasa.gov.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Spirit at the Edge of Bonneville Crater

Image credit: NASA/JPL
NASA’s Spirit has begun looking down into a crater it has been approaching for several weeks, providing a view of what’s below the surrounding surface.

Spirit has also been looking up, seeing stars and the first observation of Earth from the surface of another planet. Its twin, Opportunity, has shown scientists a “mother lode” of hematite now considered a target for close-up investigation.

“It’s been an extremely exciting and productive week for both of the rovers,” said Spirit Mission Manager Jennifer Trosper at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Dr. Chris Leger, a rover driver at JPL, said, “The terrain has been getting trickier and trickier as we’ve gotten close to the crater. The slopes have been getting steeper and we have more rocks.” Spirit has now traveled a total of 335 meters (1,099 feet).

Spirit’s new position on the rim of the crater nicknamed “Bonneville” offers a vista in all directions, including the crater interior. The distance to the opposite rim is about the length of two football fields, nearly 10 times the diameter of Opportunity’s landing-site crater halfway around the planet from Spirit.

Initial images from Spirit’s navigation camera do not reveal any obvious layers in “Bonneville’s” inner wall, but they do show tantalizing clues of rock features high on the far side, science-team member Dr. Matt Golombek of JPL said at a news briefing today. “This place where we’ve just arrived has opened up, and it’s going to take us a few days to get our arms around it.?

Scientists anticipate soon learning more about the crater from Spirit’s higher-resolution panoramic camera and the miniature thermal emission spectrometer, both of which can identify minerals from a distance. They will use that information for deciding whether to send Spirit down into the crater.

From the crater rim and during martian nighttime earlier today, Spirit took pictures of stars, including a portion of the constellation Orion. Shortly before dawn four martian days earlier, it photographed Earth as a speck of light in the morning twilight. The tests of rover capabilities for astronomical observations will be used in planning possible studies of Mars’ atmospheric characteristics at night. Those studies might include estimating the amounts of dust and ice particles in the atmosphere from their effects on starlight, said Dr. Mark Lemmon, a science team member from Texas A&M University, College Station.

Opportunity has been looking up, too. It has photographed Mars’ larger moon, Phobos, passing in front of the Sun twice in the past week, and Mars’ smaller moon, Deimos, doing so once.

Opportunity’s miniature thermal emission spectrometer has taken upward-looking readings of the atmospheric temperature at the same time as a similar instrument, the thermal emission spectrometer on NASA’s Mars Global Surveyor orbiter, took downward-pointed readings while passing overhead. “They were actually looking directly along the same path,” said science team member Dr. Michael Wolff of the Martinez, Ga., branch of the Space Science Institute, Boulder, Colo. The combined readings give the first full temperature profile from the top of Mars’ atmosphere to the surface.?

When pointed at the ground, Opportunity’s miniature thermal emission spectrometer has checked the abundance of hematite in all directions from the rover’s location inside its landing-site crater. This mineral, in its coarse-grained form, usually forms in a wet environment. Detection of hematite from orbit was the prime factor in selection of the Meridiani Planum region for Opportunity’s landing site.

“The plains outside our crater are covered with hematite,” said Dr. Phil Christensen of Arizona State University, Tempe, lead scientist for the instrument. “The rock outcrop we’ve been studying has some hematite. Parts of the floor of the crater, interestingly enough, have virtually none.” The pattern fits a theory that the crater was dug by an impact that punched through a hematite-rich surface layer, he said. One goal for Opportunity’s future work is to learn more about that surface layer to get more clues about the wet past environment indicated by sulfate minerals identified last week in the crater’s outcrop.

Christensen said that before Opportunity drives out of the crater in about 10 days, scientists plan to investigate one area on the inner slope of the crater that he called “the mother lode of hematite.”

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University at http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Lawmakers Express Concerns Over Bush Initiative

Image credit: NASA
Expert witnesses before the House Science Committee today endorsed the broad outlines of the President’s space exploration initiative, but called for changes and refinements in some of its elements.

Specifically, several witnesses criticized the reductions proposed in NASA’s space science programs to pay for the initiative, and they urged NASA to come up with new ways to get fresh ideas into the program, including from entrepreneurs and the public. The witnesses also agreed that understanding and counteracting the effects of radiation in space on human physiology is one of the most serious hurdles to sustained human activity in space. Two of the witnesses argued that the moon might not be a sensible interim goal for the exploration initiative, but others endorsed the approach outlined in the President’s plan – first the space station, then the moon and then Mars.

Committee Chairman Sherwood Boehlert (R-NY) and Ranking Democrat Bart Gordon (D-TN) both emphasized their continuing concerns with the potential costs.

“I think all I need to say about my views this morning is to reiterate that I remain undecided about whether and how to undertake the exploration program. I would add that, as the outlines of the likely fiscal 2005 budget become clearer, my questions about the initiative only become more pressing,” said Boehlert.

Boehlert added that the fiscal 2005 NASA budget proposal needed to be reviewed in the context of the entire federal science budget. “My strong feeling, and I think it’s shared by others on this Committee, is that a society unwilling to invest in science and technology is a society willing to write its own economic obituary. So we’re looking in the broad category of science?and then NASA is a subset of that, and a subset of our investment in NASA is human versus unmanned. And so we’re trying to get answers to some very specific questions involving cost and risk – answers that are not easy to come up with.”

Gordon stated, “I support the goal of exploring our solar system. However, until I am convinced that the President’s plan to achieve that goal is credible and responsible, I am not prepared to give that plan my support.”

Witnesses had differing views on the costs. Dr. Michael Griffin, President and Chief Operating Officer of In-Q-Tel, said budget estimates of the cost of the President’s initiative – “$50-55 billion to rebuild a basic Apollo-like capability by 2020” – were overestimated. He noted this estimate was considerably higher than a 1991-1993 lunar outpost study he was involved in of which top-level cost estimates were about $30 billion in 2003 dollars, or 40 percent less than the President’s proposal.

Space and Aeronautics Subcommittee Chairman Dana Rohrabacher (R-CA) asked Dr. Griffin what he would “predict it would take us to go to the moon and then to go Mars?” Griffin answered, “I believe that the first expeditions to Mars should be accomplishable within an amount of funding approximately equal to what we spent on Apollo?in today’s dollars, about $130 billion. Certainly that would envelope it. I believe that it should be possible to return to the moon for in the neighborhood of $30 billion in today’s dollars. And those are both fairly comfortable amounts.” Griffin said those missions could “easily” be accomplished within those dollar amounts in 10 years, but “you would have to decide to do it and to allocate the money, but I think that’s the level of resource commitment that’s required.”

Dr. Donna Shirley, Director of the Science Fiction Museum and Hall of Fame in Seattle and former Manager of the Mars Exploration Program at NASA’s Jet Propulsion Laboratory said she thought Dr. Griffin’s numbers were “pretty good, provided that we do the stepping-stone to the moon and we don’t stop there and we don’t start building infrastructure and don’t start doing what we did with Space Station. If we go to the moon and then right on to Mars?those are not bad numbers.”

“I do not have the figures to either agree or disagree with Dr. Griffin’s. I do however fear that once committing to go back to the moon we’ll never make it to Mars,” added Dr. Laurence Young, Apollo Program Professor at the Massachusetts Institute of Technology and Founding Director of the National Space Biomedical Research Institute in Houston.

Dr. Lennard Fisk, Chair of the National Research Council’s Space Studies Board urged policymakers to consider a “learn-as-you-go” approach. “Deciding on these answers – how fast you go back to the moon, how much does it cost you, whether you go to Mars, is going to depend on each incremental step that we go?the moon appeals to me for the simple reason that we have an opportunity to go there and try out some of our technical solutions on the way and decide whether they’re going to be adequate?The cost of this thing should not – I don’t think we should try to find a number. We should try and find a number of what are the steps that we should take on which we learn something and we adjust our program to take the next logical step – incrementally walk through this thing,” said Dr. Fisk.

Mr. Norman Augustine, chair of the Advisory Committee on the Future of the U.S. Space Program and former Chief Executive Officer of Lockheed Martin, expressed his strong support for such a “stepwise” approach over such a long-term program. “If, for example, we are to pursue an objective that requires twenty years to achieve, that then implies we must have the sustained support of five consecutive presidential administrations, ten consecutive Congresses and twenty consecutive federal budgets – a feat the difficulty of which seems to eclipse any technological challenge space exploration may engender. This consideration argues for a major space undertaking that could be accomplished in step-wise milestones, each contributing to a uniting long-term goal?It is this consideration which justifies a mission to Mars with an initial step to the moon – as philosophically opposed to a return to the moon with a potential visit to Mars.”

Space and Aeronautics Subcommittee Ranking Member Nick Lampson (D-TX) noted, “Mr. Augustine states in his written testimony that ‘it would be a grave mistake to try to pursue a space program ‘on the cheap.’ To do so is in my opinion an invitation to disaster.’ I could not agree more.”

Young discussed one of the most difficult challenges facing human missions to the moon or Mars: the impact of spending long periods in space on the human body. Dr. Young stated, “Overall, the current suite of exercise countermeasures, relying primarily on treadmill, resistance devices, is unreliable, time consuming, and inadequate by itself to assure the sufficient physical conditioning of astronauts going to Mars. Radiation remains the most vexing and difficult issue.” He discussed some research being conducted, but noted much remains to be done. He also argued, “The proposal to limit [International Space Station] research to the impact of space on human health and to end support for other important microgravity science and space technology seems short-sighted.”

Shirley also expressed several concerns with the President’s plan, noting, “The costs of the program are difficult to evaluate but there appear to be several strategic flaws, including a possibly premature phase-out of the shuttle and premature focus on a specific approach. There is no real information on which to judge the impact of exploration on other NASA missions.” She recommended that the Administration revisit the nation’s space exploration goals and suggested a process including workshops and studies that would bring in a wide-range of new stakeholders and fully engage the public in the effort.

Original Source: House Committee on Science News Release

Posted on by Fraser Cain

NASA’s Future Plans for Mars Exploration

Image credit: NASA/JPL
Since their arrivals on Mars, our two robotic wanderers have sent us incredible images and data from one of our nearest neighbors in the Solar System. The primary science objective of the Mars Exploration Rovers (MERs) is to determine to what degree the past action of liquid water on Mars has influenced the Red Planet’s environment over time.

While there is no direct evidence of liquid water on the surface of Mars today, the record of past water activity on Mars can be found in the rocks, minerals, and geologic landforms, particularly in some specific, diagnostic features that we believe form only in the presence of water. That is why both MERs are equipped with special tools to enable them to study a diverse collection of rocks and soils that may hold clues to past water activity on Mars and determine whether the planet ever had the potential to harbor life in the long-distant past, or, much less likely, today.

The information that NASA has gleaned in just the short amount of time that Spirit and Opportunity have been on the surface of Mars has been incredibly revealing. We have images that show rocks and surface structures in unprecedented detail. We are seeing a side of Mars that is vastly different from what we have encountered during past missions, because we targeted these special rovers to explore places that we knew would be compelling.

While we are incredibly pleased with the data and images we have obtained thus far and look forward to many more, we must not forget that traveling to and exploring Mars is a very challenging endeavor. As I have said many times before – both here on Capitol Hill and in the press – Mars is an extremely exciting and compelling Solar System destination, but it is also an incredibly difficult target, as history has often proven.

The landing and subsequent rollout of the two Rovers were practically picture perfect, which is a daunting engineering feat in and of itself, and one which makes me proud of NASA’s talented and capable Mars team. However, lest we became too confident about our Mars conquest, we were reminded of the significant challenges that operating on the Red Planet entails when the Spirit rover presented the Mars team with a serious technical challenge.

Spirit touched down in an area of Mars known as the Gusev Crater on January 4, 2004. After eighteen days of nearly flawless operation and after returning significant scientific data, including striking pictures of distant hills – and a rock affectionately dubbed “Adirondack ” – the Spirit rover developed an apparent communications problem that initially baffled the entire Mars team. In the ensuing days, Spirit sent us intermittent signals, and we sent the spacecraft numerous queries to try to diagnose the exact nature of the problem.

We were able to determine that the problem was related to software, and the team at JPL developed the necessary procedures and protocols to get Spirit back in business. Had Spirit’s communication problem been a hardware issue, we would be in much more dire straits for obvious reasons. Spirit is now performing as it was intended and continuing to explore its Martian surroundings.

Having actual data transmissions from Spirit’s descent to the Martian surface also provided significant benefits for the team planning the landing of the second Mars rover, Opportunity. Actual descent data from the first spacecraft were used to confirm our models of the behavior of the Martian atmosphere and weather – models which we depended on to plan Opportunity’s descent. The data from Spirit indicated that, while the descent was within the predicted limits of our engineering model, it was close to edge of the anticipated margins.

Armed with this new knowledge, NASA opted to open Opportunity’s parachute earlier to provide for a slower descent and a more gentle arrival on the Red Planet. On January 25, 2004, Opportunity bounced onto the opposite side of Mars – in an area called Meridiani Planum – from where its twin had landed.

The new landing location was “a world away ” from Gusev Crater in more ways than just distance. The initial images transmitted later that day fascinated the science team, revealing an area of dark soil and possible bedrock – a feature we have long searched for but never seen before on any planet’s surface – interspersed with patches of the more familiar red Martian soil. This region of Mars particularly interested planetary geologists because they believed it may contain abundant deposits of hematite, a mineral that, when found on Earth, has usually formed in the presence of persistent liquid water. We now know that their suspicions were correct.

On March 2, 2004, NASA announced that the Opportunity rover had found strong evidence that the area called Meridiani Planum was once soaking wet. Evidence found in an outcrop of rock led scientists to this important conclusion. Clues from the rocks’ composition, such as the presence of sulfates and salts, and the rocks’ physical attributes (e.g., niches where crystals once grew) helped make the case for a watery history. This area is scientifically compelling, and we intend to study it in further detail, hopefully revealing more secrets of the Red Planet.

Missions to Mars are launched approximately every two years (26 months), when the orbital alignments of the Earth and Mars allow the minimum amount of fuel to be used on the long trip. At each of these launch opportunities, NASA plans to send robotic spacecraft to Mars to continue searching for evidence of water, studying the rocks and soil of the planet, and attempting to answer the question, “Did life ever arise on Mars?” The Mars Exploration Program will attack this question by seeking to understand, in a systematic way, the current state and evolution of the atmosphere, surface, and interior of Mars, the potential for life on Mars in the past or present, and develop knowledge and technology necessary for future human exploration.

NASA’s Mars Program
This program is the result of an intensive planning process involving the broad science and technology community. The program incorporates the lessons learned from previous missions and builds upon, as well as responds to, scientific discoveries from past and on-going missions. In addition to the MERs, missions that comprise this systematic approach to Mars exploration are:

1. Mars Global Surveyor (MGS) – launched in 1996, this mission continues to return an unprecedented amount of data regarding Mars’ surface features and composition, atmosphere, weather, and magnetic properties. Scientists are using the data gathered from this mission both to learn about the Earth by comparing it to Mars and to build a comprehensive data set to aid in planning future missions. MGS also serves as a telecommunications relay for the MER missions, as well as a device for photographing landed spacecraft on the surface, such as the rovers.

2. Mars Odyssey – launched in 2001, the Odyssey orbiter is presently mapping the mineralogy and morphology of the Martian surface while achieving global mapping of the elemental composition of the surface and the abundance of hydrogen in the shallow subsurface. Its maps of hydrogen have suggested vast amounts of near-surface water ice in the polar regions of the planet. It also serves as a telecommunications relay for the MER missions.

3. Mars Reconnaissance Orbiter (MRO) – scheduled for launch in 2005, MRO will focus on analyzing the surface at unprecedented new scales in an effort to follow tantalizing hints of water detected in images from the MGS and Odyssey spacecraft and to bridge the gap between surface observations and measurements from orbit. For example, MRO will measure thousands of Martian landscapes at 20- to 30-centimeter (8- to 12-inch) resolution, enabling observation of features the size of beach balls, while also mapping their mineralogies. This will help NASA target future landed laboratories to the best sites to search for evidence of life.

4. Phoenix – scheduled to launch in 2007, this mission will conduct a stationary, surface-based investigation of water ice contained within Martian soils, as well as searching for organic molecules and observing modern climate dynamics. It aims to “follow the water” and measure indicator molecules at high-latitude sites where Mars Odyssey has discovered evidence of large water ice concentrations in the Martian soil. Phoenix was selected as the first of the competed Mars Scout missions.

5. Mars Science Laboratory (MSL) – schedule to launch in 2009, this next generation rover represents a major leap in surface measurements and pave the way for future sample return and astrobiology missions. A long-life power source is planned to allow the science laboratory to conduct experiments for up to two years. Instruments for this surface laboratory may provide direct evidence of organic materials, if any exist, and will be able to search up to several feet beneath the surface. MSL will also demonstrate technologies for accurate landing and hazard avoidance in order to reach what may be very promising, but difficult-to-reach, scientific sites. Its landing location will be based on observations by the Mars Reconnaissance Orbiter. In the ensuing decade, from 2011-2018, NASA plans additional science orbiters, rovers, and landers, and the first mission to return the most promising Martian samples to Earth.

Current strategies call for the first sample return mission to be launched by 2014. Options that would significantly increase the rate of missions launched and/or accelerate the schedule of exploration are under study. Technology development for advanced capabilities, such as miniaturized surface science instruments and deep drilling to several hundred feet, will also be carried out in this period.

NASA has developed a campaign to explore Mars that will change and adapt over time in response to what is discovered and learned with each mission. The plan is meant to be a robust, flexible, long-term program that will provide the highest probability for success. We are moving from the early era of global mapping and limited surface exploration to a much more intensive and discovery-responsive approach. We will establish a sustained presence in orbit around Mars and on the surface with long-duration exploration of some of the most scientifically promising and intriguing places on the planet.

We plan to “follow the water,” so that in the not-too-distant future we may finally know the answers to the most far-reaching questions about the Red Planet we humans have asked over the generations: Did life ever arise there, and does life exist there now?

What’s Next
On January 14, 2003, President Bush announced his new vision for NASA and the Nation’s space program, and just last month the President’s FY 2005 budget was released. Both of those events support and indeed strengthen NASA’s vision for Mars exploration over the next decade and beyond. NASA’s comprehensive, robotic approach to exploring Mars and learning the intricacies of its environment will not only seek to achieve the science goals outlined in this testimony, it will also serve as a solid foundation for the President’s vision of eventually conducting a human exploration mission to Mars.

Original Source: Astrobiology Magazine

Posted on by Fraser Cain

Rosetta’s Asteroid Targets Decided

Image credit: ESA
Today the Rosetta Science Working Team has made the final selection of the asteroids that Rosetta will observe at close quarters during its journey to Comet 67P/Churyumov-Gerasimenko. Steins and Lutetia lie in the asteroid belt between the orbits of Mars and Jupiter.

Rosetta’s scientific goals always included the possibility of studying one or more asteroids from close range. However, only after Rosetta’s launch and its insertion into interplanetary orbit could the ESA mission managers assess how much fuel was actually available for fly-bys. Information from the European Space Operations Centre (ESOC) in Germany enabled Rosetta’s Science Working Team to select a pair of asteroids of high scientific interest, well within the fuel budget.

The selection of these two excellent targets was made possible by the high accuracy with which the Ariane 5 delivered the spacecraft into its orbit. This of course leaves sufficient fuel for the core part of the mission, orbiting Comet 67P/Churyumov-Gerasimenko for 17 months when Rosetta reaches its target in 2014.

Asteroids are primitive building blocks of the Solar System, left over from the time of its formation about 4600 million years ago. Only a few asteroids have so far been observed from nearby. They are very different in shape and size, ranging from a few kilometres to over 100 kilometres across, and in their composition.

The targets selected for Rosetta, Steins and Lutetia, have rather different properties. Steins is relatively small, with a diameter of a few kilometres, and will be visited by Rosetta on 5 September 2008 at a distance of just over 1700 kilometres. This encounter will take place at a relatively low speed of about 9 kilometres per second during Rosetta’s first excursion into the asteroid belt.

Lutetia is a much bigger object, about 100 kilometres in diameter. Rosetta will pass within about 3000 kilometres on 10 July 2010 at a speed of 15 kilometres per second. This will be during Rosetta’s second passage through the asteroid belt.

Rosetta will obtain spectacular images as it flies by these primordial rocks. Its onboard instruments will provide information on the mass and density of the asteroids, thus telling us more about their composition, and will also measure their subsurface temperature and look for gas and dust around them.

Rosetta began its journey just over a week ago, on 2 March, and is well on its way. Commissioning of its instruments has already started and is proceeding according to plan.

“Comets and asteroids are the building blocks of our Earth and the other planets in the Solar System. Rosetta will conduct the most thorough analysis so far of three of these objects,” said Prof. David Southwood, Director of ESA?s Science Programme. “Rosetta will face lots of challenges during its 12-year journey, but the scientific insights that we will gain into the origin of the Solar System and, possibly, of life are more than rewarding.”

Original Source: ESA News Release

Posted on by Fraser Cain

Prints Available For Hubble Deep Field

After yesterday’s wallpaper image of the new Hubble Deep Field Survey containing more than 10,000 galaxies, I had a couple of requests from people for me to a make a printed version available. Done. Click this link to go to the photo gallery, and then click on “Hubble Space Telescope”. The first image is of the survey, and you can order a printed copy up to 20″ x 30″.

Thanks!

Fraser Cain
Publisher
Universe Today

Posted on by Fraser Cain

Early Oceans Might Have Had Little Oxygen

Image credit: NASA
As two rovers scour Mars for signs of water and the precursors of life, geochemists have uncovered evidence that Earth’s ancient oceans were much different from today’s. The research, published in this week’s issue of the journal Science, cites new data that shows that Earth’s life-giving oceans contained less oxygen than today’s and could have been nearly devoid of oxygen for a billion years longer than previously thought. These findings may help explain why complex life barely evolved for billions of years after it arose.

The scientists, funded by the National Science Foundation (NSF) and affiliated with the University of Rochester, have pioneered a new method that reveals how ocean oxygen might have changed globally. Most geologists agree there was virtually no oxygen dissolved in the oceans until about 2 billion years ago, and that they were oxygen-rich during most of the last half-billion years. But there has always been a mystery about the period in between.

Geochemists developed ways to detect signs of ancient oxygen in particular areas, but not in the Earth’s oceans as a whole. The team’s method, however, can be extrapolated to grasp the nature of all oceans around the world.

“This is the best direct evidence that the global oceans had less oxygen during that time,” says Gail Arnold, a doctoral student of earth and environmental sciences at the University of Rochester and lead author of the research paper.

Adds Enriqueta Barrera, program director in NSF’s division of earth sciences, “This study is based on a new approach, the application of molybdenum isotopes, which allows scientists to ascertain global perturbations in ocean environments. These isotopes open a new door to exploring anoxic ocean conditions at times across the geologic record.”

Arnold examined rocks from northern Australia that were at the floor of the ocean over a billion years ago, using the new she had method developed by her and co-authors, Jane Barling and Ariel Anbar. Previous researchers had drilled down several meters into the rock and tested its chemical composition, confirming it had kept original information about the oceans safely preserved. The team members brought those rocks back to their labs where they used newly developed technology -called a Multiple Collector Inductively Coupled Plasma Mass Spectrometer-to examine the molybdenum isotopes within the rocks.

The element molybdenum enters the oceans through river runoff, dissolves in seawater, and can stay dissolved for hundreds of thousands of years. By staying in solution so long, molybdenum mixes well throughout the oceans, making it an excellent global indicator. It is then removed from the oceans into two kinds of sediments on the seafloor: those that lie beneath waters, oxygen-rich and those that are oxygen-poor.

Working with coauthor Timothy Lyons of the University of Missouri, the Rochester team examined samples from the modern seafloor, including the rare locations that are oxygen-poor today. They learned that the chemical behavior of molybdenum’s isotopes in sediments is different depending on the amount of oxygen in the overlying waters. As a result, the chemistry of molybdenum isotopes in the global oceans depends on how much seawater is oxygen-poor. They also found that the molybdenum in certain kinds of rocks records this information about ancient oceans. Compared to modern samples, measurements of the molybdenum chemistry in the rocks from Australia point to oceans with much less oxygen.

How much less oxygen is the question. A world full of anoxic oceans could have serious consequences for evolution. Eukaryotes, the kind of cells that make up all organisms except bacteria, appear in the geologic record as early as 2.7 billion years ago. But eukaryotes with many cells-the ancestors of plants and animals- did not appear until a half billion years ago, about the time the oceans became rich in oxygen. With paleontologist Andrew Knoll of Harvard University, Anbar previously advanced the hypothesis that an extended period of anoxic oceans may be the key to why the more complex eukaryotes barely eked out a living while their prolific bacterial cousins thrived. Arnold’s study is an important step in testing this hypothesis.

“It’s remarkable that we know so little about the history of our own planet’s oceans,” says Anbar. “Whether or not there was oxygen in the oceans is a straightforward chemical question that you’d think would be easy to answer. It shows just how hard it is to tease information from the rock record and how much more there is for us to learn about our origins.”

Figuring out just how much less oxygen was in the oceans in the ancient past is the next step. The scientists plan to continue studying molybdenum chemistry to answer that question, with continuing support from NSF and NASA, the agencies that supported the initial work. The information will not only shed light on our own evolution, but may help us understand the conditions we should look for as we search for life beyond Earth.

Original Source: NSF News Release