After months of meetings, the panel of space experts appointed by President Obama to evaluate NASA’s manned spaceflight program has returned with a dire assessment: lack of financing has put the program on an “unsustainable trajectory.” The executive summary (pdf) of the report, released yesterday, puts forth a number of ideas for how the space agency can live within its means, but the final decisions on whether to act on the ideas rests with President Obama and Congress.
Among other recommendations, the panel suggested that NASA shelve its goal of rapidly returning to the moon and instead focus on nurturing a robust commercial space industry that can handle short-term objectives of the nation’s space program, such as ferrying cargo and crew to the international space station [The Wall Street Journal]. By canceling a return to the moon (which had been scheduled for around 2020) and outsourcing routine resupply missions, the panel suggested that NASA would be able to work towards more ambitious, deep space missions like a trip to an asteroid or an expedition to Mars.
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Engines powered by chemical fuel? How passé. For the spacecraft with truly modern flair, an ion thruster is the only way to go. Such a system might not provide powerful and dramatic bursts of speed, but space agencies around the world are recognizing the benefits of its slow-and-steady approach, which is just what’s needed for cruising between planets.
Ion propulsion works by electrically charging, or ionizing, a gas and accelerating the resulting ions to propel a spacecraft. The concept was conceived more than 50 years ago, and the first spacecraft to use the technology was Deep Space 1 in 1998. Since then … there have only been a few other noncommercial spacecrafts that have used ion propulsion [Technology Review]. However, the technology has a clear advantage over chemical propulsion when it comes to long distance missions, because a very small amount of gas can carry a spacecraft a long way. Astronautics expert Alexander Bruccoleri explains that with chemical propulsion, “You are limited in what you can bring to space because you have to carry a rocket that is mostly fuel” [Technology Review].
Now, a European Space Agency (ESA) probe will use four ion thrusters to scoot all the way to Mercury, the planet nearest to the sun. That mission won’t launch until 2014, but ESA officials say the $37 million propulsion system will be the most efficient yet, and will also be the most ambitious test of the technology to date. The Mercury probe will be launched by a conventional rocket, and will continue to use chemical propulsion until it’s out of Earth orbit. When it begins its six-year cruise to Mercury, though, its ion thrusters will kick in. The system will draw electricity from solar panels; as the xenon ions pass through the electrified grids they accelerate to up to 50km a second (31 miles per second) and shoot from the rear in a parallel beam. On Earth, at sea level, the thrust would be just enough to lift a pound coin. In space, however, the same thrust will create a much much bigger lift [Telegraph].
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The Mars rover Opportunity, an interloper on the Martian soil, has discovered another piece of metal that isn’t native to the planet: a boulder-sized iron meteorite that spun out of the sky and crashed into the planet sometime in the distant past. While the rock isn’t the first iron meteorite spotted on Mars (the two Mars rovers’ previous discoveries make this the fourth), it is the largest, measuring about 2 feet wide and 1 foot high. Researchers hope that studying the mega-meteorite will provide clues to the atmosphere and landscape that it encountered when it arrived on Mars.
Opportunity spotted the out-of-place object on July 18 and snapped a picture of it, but the rover was on its way towards a distant crater and didn’t stop. When NASA scientists saw the photographs, however, they ordered the rover to reverse course and head for the rock. “When you’re driving around on relatively smooth, flat, boring plains for a long time, anything that looks like a decent-sized rock says, ‘Come get me!’” says team member Albert Yen, a planetary scientist at NASA’s Jet Propulsion Laboratory [New Scientist].
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A panel evaluating NASA’s goals has made some bold suggestions for the agency, including yearlong missions into deep space and even landing on Mars‘ moon, Phobos.
NASA’s current goal is to land humans on the moon once again by 2020, but the panel, which was set up by the White House, has suggested other possible ventures that could speed NASA towards another goal: a manned mission to Mars. For example, long missions to deep space would help scientists learn how to manage long-duration space missions far from Earth, which human missions to Mars would require…”It is true we need to gain experience exploring planetary surfaces, but in fact we’ve done some of that…. What we actually have almost no experience at all with is operations in deep space” [New Scientist], said committee member Edward Crawley. Missions into deep space would require further research into how to protect humans from space radiation, the harmful charged particles from which lower-orbit missions are shielded by the Earth’s magnetic field.
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What lies beneath the icy crust of Enceladus? Ever since the NASA space probe Cassini snapped pictures of the Saturnian moon expelling enormous jets of icy vapor from fissures near its south pole in 2005, planetary scientists have debated whether the evidence points to liquid oceans beneath the moon’s surface. Now, a new chemical analysis of the plume bolsters the oceanic theory, thanks to the detection of a mundane chemical: ammonia. Says study coauthor Jonathan Lunine: “This is the first time Cassini has actually been able to ’smell’ ammonia…. And because ammonia is an antifreeze, it probably ensures that there is liquid water in the interior of Enceladus.” And where there’s water, there could be life [Wired.com].
Last month, another team of researchers also argued for the presence of an ocean when they published their discovery of sodium salts in Saturn’s outer-most ring which is thought to originate from Enceladus’ plume material. “The two studies are complimentary and now, for the first time, we are getting an idea of the full picture of what’s happening on Enceladus,” [Chemistry World], says Frank Postberg, lead author of that earlier study. However, Postberg’s study was contested by another paper that found no traces of sodium vapor around Enceladus, leaving the debate unresolved. Sodium is thought to be an indicator of liquid water because it suggests that salt leached from rocks into the water.
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Jupiter is sporting a new, Earth-sized scar near its south pole, and NASA has confirmed that the gas giant was thumped by a massive impact over the past few days. The discovery was made Sunday night by a Australian computer programmer who uses his spare time to stargaze with his backyard telescope, and today NASA declared that the dark spot is definitely not a weather system, and is indeed evidence of a collision. It’s not yet known exactly what smacked into Jupiter; astronomers say it could have been an unknown comet, or a stray piece of ice.
This is only the second time such an impact has been observed. The first was almost exactly 15 years ago, when more than 20 fragments of comet Shoemaker-Levy 9 collided with the gas giant. “This has all the hallmarks of an impact event, very similar to Shoemaker-Levy 9,” said Leigh Fletcher, an astronomer at NASA’s Jet Propulsion Lab…. “We’re all extremely excited” [New Scientist].
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Forty years ago today, two men walked on the moon. To celebrate that moment of transcendent ambition and triumph, the world is looking back to July 20, 1969: NASA has released restored video footage of the Apollo 11 landing, and a new NASA moon orbiter has taken snapshots of the Apollo landing site, where left-behind gear still sits on the lunar surface. But for some space buffs, the anniversary has a touch of melancholy to it.
For all the promised “giant leap for mankind” the mission foretold, the prophesied future of moon bases and journeys to Mars, Jupiter and beyond is still science fiction. The last of six moon landings, bringing two men each time to the lunar surface, was in 1972. Since then, no one has left low Earth orbit. For many advocates, there is a consensus that the National Aeronautics and Space Administration is suffering from what President Obama this March called “a sense of drift” [Washington Post].
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On July 21, 1969, Neil Armstrong and Buzz Aldrin were packing up equipment in their lunar lander, getting ready to blast back to the moon’s orbit where command module was waiting to bring the Apollo 11 mission back home. But another dramatic scene was also taking place on the lunar surface: the unmanned Russian probe Luna 15 was crashing to the ground. Now, never-before released recording—from a British control room that was monitoring all the lunar activity—transports the listener back to that tight finale of the moon phase of the space race, 40 years ago.
The recordings were made over three days at the Jodrell Bank Observatory in Manchester, where researchers used the Lovell Radio Telescope to listen to transmissions from Apollo 11—and Luna 15. Sir Bernard Lovell, the inventor of the telescope and the founder of Jodrell Bank, can be heard narrating events with conversation from the Apollo 11 astronauts in the background. Sir Bernard notes a change in the orbit of Luna 15 to take it closer to the US landing site and later reports a rumour from a “well-informed source in Moscow” that the craft is about to land. People in Jodrell’s control room can then be heard shouting “it’s landing” and “it’s going down much too fast” as they track Luna 15’s final moments before it crashes [Telegraph].
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How do you extract a vehicle from a sand trap when the operation has to happen remotely from a distance of 174 million miles? That’s the question that NASA scientists are attempting to answer at the Jet Propulsion Laboratory in California, where engineers are working on a plan for how to get the Mars rover Spirit moving again. The rover has been stuck, up to its hubcaps in sand, since April 23rd when it drove backwards into an area now called “Troy.”
To test strategies for how to get the rover unstuck, scientists built a sandbox that resembles that patch of Martian terrain, and then drove a rover replica into it. Spirit project manager John Callas explains that the scientists carefully mixed sand, pottery clay, and a light material called diatomaceous earth to imitate the dirt on Mars. While the ingredients do not match the Martian soil’s chemistry, the mixture has a similar strength. “It is representative of the trouble Spirit is in … in very, very fluffy soil with very little load bearing strength,” Dr Callas said. “It’s like talcum powder, but not as fine grained. It clings to the wheels and they lose traction.” Adding to their problems, the rover is tilted on a 12-degree slope [The Age].
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The solar probe Ulysses has circled the sun for more than 18 years–almost as long as the Greek hero Odysseus, also called Ulysses, was absent from home due to the Trojan War and his prolonged journey home–but the space probe doesn’t have a homecoming in its future. Ulysses will receive its final transmission tomorrow, as researchers say the scientific findings sent home by the failing spacecraft no longer justify the mission’s costs. After shut-off, Ulysses will continue to orbit the Sun, becoming in effect a man-made ‘comet’. “Whenever any of us look up in the years to come, Ulysses will be there, silently orbiting our star, which it studied so successfully during its long and active life” [SPACE.com], says mission manager Richard Marsden.
The craft has already exceeded expectations. In February 2008, mission engineers announced with great solemnity and with heaps of praise for the orbiter that the craft would fall silent within a few months. Its power supply had grown too weak to keep the craft’s fuel lines from freezing. Not so fast: Engineers figured out that they could keep the lines warm by firing the craft’s thrusters in short bursts every couple of hours [The Christian Science Monitor]. Using that clever fix, Ulysses soldiered on for another year.
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As the second man to ever walk on the moon (he stepped out of the lunar module about 15 minutes after Neil Armstrong), Buzz Aldrin knows a little something about space exploration, about bold ambitions and great risks. Now, Aldrin is speaking out about NASA, and declaring loudly that the space agency has lost its boldness. The next step in humanity’s exploration of space must be a bootprint on Mars, he says.
Says Aldrin: “As I approach my 80th birthday, I’m in no mood to keep my mouth shut any longer when I see NASA heading down the wrong path. And that’s exactly what I see today. The agency’s current Vision for Space Exploration will waste decades and hundreds of billions of dollars trying to reach the moon by 2020—a glorified rehash of what we did 40 years ago. Instead of a steppingstone to Mars, NASA’s current lunar plan is a detour” [Popular Mechanics].
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Saturn’s moon Enceladus got humanity’s attention in 2005 when surprised astronomers detected jets of ice and gas spraying out from the moon’s icy surface, and since then researchers have eagerly investigated the possibility that the jets might emanate from liquid oceans beneath the frozen crust. A moon with liquid water would be of great interest, because it would be more likely to host extraterrestrial microbes. Now, two new studies with somewhat contradictory results have deepened the mystery of what lies beneath Enceladus’s shell of ice.
Both groups of researchers were looking for sodium near Enceladus; one found it, the other didn’t. Sodium is interesting because it indicates that deep under the ice, liquid water has been in contact with rocks, which leach salts [ScienceNOW Daily News]. The dissolved sodium, along with water, would be shot into space in the geysers, and some of the sodium would be trapped in ice crystals as they formed. The first research group found sodium traces in Saturn’s E ring, a wide band of ice particles that is believed to be replenished by Enceladus’s jets. “Those salty grains provide our current best smoking (or steaming) gun pointing to present-day liquid water near the surface of Enceladus” [Wired.com], wrote space scientist John Spencer in an essay accompanying the findings.
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Five days after their launch, NASA’s two new lunar probes have successfully rendezvoused with their target. The Lunar Reconnaissance Orbiter fired its thrusters this morning to settle into orbit around the moon, while the Lunar Crater Observation and Sensing Satellite (LCROSS) swung past the moon, streaming live video all the while. (NASA promises to put the video playback online soon.)
The paired satellites will spend the next year mapping the moon and searching for traces of water ice, culminating in a dramatic crash when LCROSS plunges into a crater. But for now, NASA is busy celebrating the successful first steps. The $504 million LRO is the first NASA vessel to orbit the moon since 1998. “LRO has returned NASA to the moon,” a flight controller said as NASA’s LRO mission control center erupted in applause. The probe’s lunar arrival comes just under one month ahead of the 40th anniversary of NASA’s first moon landing by Apollo 11 astronauts on July 20, 1969 [SPACE.com].
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NASA is turning its attention back on a familiar target–the moon–but in service of a unprecedented goal. Two new spacecraft are expected to launch this week on a robotic mission aimed at finding the best site for Earth’s first off-world colony, the centuries-old dream of science fiction writers and utopians…. “We’re going to provide NASA with what is needed to get human beings back to the moon and to stay there for an extended duration” [Los Angeles Times], explains NASA’s Craig Tooley. However, whether such a lunar outpost will ever be built is still an open question.
The spacecraft duo comprises an orbiter and a crash-lander; the two spacecraft will take off for the moon aboard a single Atlas V rocket, but once in space they’ll separate and take different routes. The Lunar Reconnaissance Orbiter (LRO) will make a four-day journey to the moon’s orbit where it will begin mapping the moon’s surface, looking for potential moon base sites in polar locations that are bathed in near-constant sunlight (which would be useful for solar panels). The orbiter will also carry pieces of plastic designed to simulate the density and chemical proportions of human skin and muscle…. The LRO’s particle detectors will measure how this plastic interacts with cosmic rays – a form of space radiation made up of particles such as protons that can lead to cancer by damaging DNA [New Scientist].
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For two years, the Mars rover Opportunity explored the Victoria crater and dutifully sent back reports on the sedimentary rock layers on display in the crater walls and the scattering of pebbles on the sunken floor. Now, the results of that comprehensive survey have been compiled and compared to data gleaned from Opportunity’s exploration of two smaller craters several miles away. The study shows that shifting sand dunes on ancient Mars once concealed a network of underground water spread across an area the size of Oklahoma…. “Given that we’ve seen the same stuff at places that are miles apart, it is a reasonable conjecture that those processes operated over most of this region” [National Geographic News], says lead researcher Steve Squyres.
The rover had previously explored the Eagle and Endurance craters, about 3.7 miles (6 kilometers) away from Victoria. Mission scientists chose Victoria as the next crater to explore because “it was the biggest crater we could possibly find,” said Steve Squyres…. The science team hoped that Victoria’s depth — of about 400 feet (125 meters) — might shed more light on the geology of the Meridiani Planum region [LiveScience]. Like a child in a fairy tale following a trail of pebbles, Opportunity also studied the small, round rocks made of the mineral hematite as it trundled towards the Victoria crater in 2006.
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