Titan teaches truth about hazy planets

Titan's haze is providing astronomers with new clues about how to study the atmospheres of alien worlds orbiting distant stars (Source: NASA/JPL-Caltech)

Haze in a planet's atmosphere can dramatically effect what astronomers can tell about that planet, according to a new NASA study.

The research, published this week in the Proceedings of the National Academy of Sciences, found the haze shrouded skies of Saturn's moon Titan prevented scientists from analysing more than the top few kilometres of atmosphere.

The study, led by Dr Tyler Robinson from NASA's Ames Research Centre, California, is providing astronomers with new clues about studying the atmospheres of alien worlds orbiting distant stars.

"A lot of planets around other stars have haze or clouds in their atmospheres, limiting our ability to figure out what atmospheres on these distant worlds are made of," says Robinson.

"So we wanted to look for somewhere in the solar system that also had haze or high altitude cloud that might tell us something about how it influences observations of exoplanets."

Astronomers can determine the composition of a planet's atmosphere by looking for specific chemical signatures called spectra in light shining through it as it passes in front of its host star.
Titan test

Robinson and colleagues used data collected by NASA's Cassini spacecraft during four Titan flybys between 2006 and 2011.

The authors were able to examine the sunlight as it passed through the moon's atmosphere.

The observations allowed the researchers to see Titan as if it were a transiting exoplanet, without having to leave the solar system.

The transits revealed just how dramatic the effects of haze can be.

"We were surprised at how strongly the haze prevents our ability to see down into the deep atmosphere of Titan," says Robinson.

"Titan's atmosphere is a little bit thicker than Earth's, but because of the haze we couldn't see below a hundred kilometres above the surface. We were limited to only seeing light passing through the very upper most portions of Titan's atmosphere."

Atmospheric chemical composition can vary significantly at different altitudes. Earth for example has a lot more water vapour down deep near the surface than at higher altitudes where it's cold.
Hazy result

Robinson and colleagues were also surprised to see the haze changes the observations.

"Many astronomers assumed that when you're looking at an exoplanet and you see a haze, it would be colourless, like a cloud is white on Earth," says Robinson.

"But in Titan's case the haze is actually a strong red colour, so red light is far less attenuated than the blue light. The colour of the haze is just as dramatic as the effects gasses cause in Titan's atmosphere."

As a result of the study, hazes are far more complicated than scientists initially thought.

"It's telling us to be careful about how we go about detecting molecules in the atmosphere of distant worlds," says Robinson.

"If that world has a haze we can be completely prevented from seeing the deep atmosphere which means that we couldn't detect all the molecules present in that atmosphere."

New Mars Lander to Probe Interior of Red Planet

The U.S. space agency, NASA, recently gave the green light for the construction of a new Mars lander that will examine the deep interior of the Red Planet.

The new Mars mission is called the Interior Exploration Using Seismic Investigation Geodesy and Heat Transport, which is why everyone knows it by its acronym: InSight. The mission’s spacecraft is scheduled to launch from California’s Vandenberg Air Force Base in March 2016 and due to arrive on Mars later that year, in September.

Bruce Banerdt, from NASA’s Jet Propulsion Laboratory, is the InSight’s principal investigator. He said that some of the technology the lander will use to study the interior of Mars is similar to what geologists have been using to study the Earth.

“The idea behind it is to use some geophysical instruments, mostly a seismometer and a heat-flow probe to better understand the interior structure of Mars, both its composition, layering, what’s going on inside, stuff like that,” said Banerdt.

InSight’s study of the interior of Mars may not only provide a fresh look into the creation of our own planet but also other Earth-like planets located within and beyond our solar system.

“We really want to understand how the terrestrial planets, the rocky planets, formed early on in the solar system, and how that formation sort of led to the kinds of conditions we have on the surface,” said Banerdt.

Unlike the popular Curiosity and Opportunity rovers that are traveling across Mars, the InSight will be sent to a location near the Red Planet’s equator and remain stationary to conduct its research.

Banerdt said that the new Mars lander will map out the geography of the deep Martian interior.

“And by that I mean how thick is the crust, what’s the crust made out of? And then how big is the core, what is it made out of? What are the thermal characteristics of everything in terms of the heat flow, energy production? Things like that,” said Banerdt.

Multinational effort

The spacecraft will carry a bevy of sophisticated new instruments to carry out its mission. The space agencies of Germany, France, Switzerland and the United Kingdom are providing two of the most important tools for the mission.

Among InSight’s instruments is a seismometer that will measure and analyze seismic waves that shake the ground, mostly due to quakes.

Another tool aboard the Mars lander is a heat-flow probe that will burrow itself down about 4.5 to 5 meters beneath the planet’s surface. The device will measure small increases in temperature as it tunnels further into the crust of Mars. Banerdt said this tool will allow his research team to figure out how much heat is coming from the planet’s interior.

“This heat flow is what drives a lot of the geology: it drives volcanism; on Mars, it can drive uplift of mountain ranges; and so the amount of heat coming out of it is a basic parameter that we need to learn in order to find out how active a planet is,” said Banerdt.

And, one important tool that will be used to conduct InSight’s research isn’t really an instrument, but rather, a radio on the spacecraft that will send out signals that will be tracked here on Earth by project scientists.

Following the signal produced by the radio sitting on the rotating planet will allow the research team to watch Mars rotate on its axis and actually watch that axis “wobble a little bit.”

“The size of that wobble tells us about the distribution of material inside the planet. So by using an analysis of this wobble, we can tell the details of the core. Because that’s what really drives the magnitude of these wobbles - it’s the size of the core, its density, and whether it’s solid or liquid,” said Banerdt.

The new Mars lander will also be equipped with a weather station and camera that will provide further information about the Red Planet.

InSight’s mission is expected to last for about one Mars-year or two Earth years.

By better understanding what’s behind the interior of Mars, Banerdt said that scientists will be able to get a better idea of what the Earth might have looked like very early in its history.

Robots Will Pave the Way to Mars

                                       

The first robot capable of building anything including a replica of itself, might cost a fortune to develop; the billionth copy would be as cheap as dirt. Send some of them into space and they could build new armies out of planetary rubble and dust, then go on to construct enough spaceships and refueling stations to carry the human race to other planets and, eventually, other stars.

That’s the scenario laid out some 35 years ago by a team of academics and NASA engineers meeting at the University of Santa Clara, in California. They envisioned robotic factories that would cover the moon and exploit the asteroid belt, extracting the resources needed to build more and better versions of themselves and also vast orbiting telescopes, space colonies, and other structures too big to launch from Earth. Over time, the researchers wrote, these bots could “produce an ever-widening habitat for man throughout the Solar System” and beyond it. The approach could become so successful, they warned, that we might have to worry about robotic population control.

None of that, of course, has come to pass. Except for solar power, everything we use in space comes from Earth. But signs of change might be on the horizon. The next few years will see the launch of the first equipment that can make water out of lunar soil and print entirely new structures in microgravity. These are the seeds of the two basic technological capabilities—resource extraction and structure fabrication—that will be needed to build things in space that don’t have to be launched from Earth.

If these technologies mature, experts say, they could transform the space environment. In 50 years, commercial outfits may tow drinking water, extracted from icy asteroids, to thirsty astronauts in Earth orbit. Vast solar arrays, built on trusses made from cemented lunar soil, could beam energy to Earth’s surface. Radio antennas hundreds of meters wide could scrutinize the black hole at the center of the galaxy. And humans could finally be able to gather the resources they need for round-trip journeys to the surface of Mars.

Nothing about this future is guaranteed. Space plans shift with the political winds, and there is perennial debate over why we should go to space and what the balance of human and robotic exploration should be.

But robotic systems capable of construction and resource utilization could address the single biggest obstacle to the exploration of space: the expense.

“The technical facts of life in space are that it’s hard to get there, it’s hard to stay there, and it costs money to do it repeatedly,” says Paul Spudis, a scientist at the Lunar and Planetary Institute, in Houston. Rocket companies still charge roughly US $10 000 to $20 000 to loft every kilogram of stuff into low Earth orbit. Many are now eying newcomer SpaceX, which is promising to deliver lower prices with a new heavy-lift rocket. But driving down the costs significantly would require either many more launches, to achieve economies of scale, or an improvement on chemical rocketry. Neither is on the horizon, Spudis says, and that leaves us with one alternative. To get beyond low Earth orbit and the half dozen lunar landings already under our belts, we must find a way to live off the land.

The moon alone has plenty of raw material to go around. The loose soil can be sintered or glued together to make crude structures. Silicon, which makes up roughly 20 percent of the soil by weight, can be extracted and purified to create rudimentary solar cells. And, crucially, there seems to be water, a multipurpose resource that can be purified for drinking, poured into containers to make radiation shielding, and split into hydrogen and oxygen to form rocket fuel. The ice locked up in the moon’s north pole alone, Spudis says, is “enough to launch the equivalent of a space shuttle from the surface of the moon every day for 2200 years.”

We could do far more in space if we make what we need out of what we can find, says Mason Peck, a professor of mechanical and aerospace engineering at Cornell and former NASA chief technologist. “I like to say that all the mass we’re ever going to need to explore in space is already in orbit. It’s just in the wrong shape.”

Getting mass into the right shape is one of the goals of NASA’s Swamp Works. The laboratory, based at Kennedy Space Center, in Merritt Island, Fla., occupies a building where Apollo astronauts once trained; it now boasts perhaps the world’s largest collection of “lunar simulant”—artificial moon dirt. Some 120 tons of the stuff, detritus of a mining operation in Black Point, Ariz., sit in a glass-walled room. Here physicist Philip Metzger and his colleagues test the Regolith Advanced Surface Systems Operations Robot, or RASSOR, a rugged-looking industrial rover the size of a bumper car. RASSOR is more or less rectangular when stretched out. At each end, a pair of pivoting arms holds a long, hollow, rotating drum, studded with shovel-shaped openings. For digging leverage against the moon’s reduced gravity, these drums are rotated in opposite directions, collecting lunar soil as they spin. When full, the robot can drive to a processing station, fold up so as to place a drum above a collection spot, and rotate the drum in reverse to empty it.


NASA's space digging RASSOR Robot


Metzger expects that such technology could kick off a lunar industry that slowly bootstraps its way up in sophistication. Crude robotic factories, remotely operated by humans, would be used to build slightly more capable systems, which would make even more capable ones, and so on. Metzger and his colleagues have modeled how this might work, and they reckon that as little as 12 metric tons of equipment sent to the moon would be enough to jump-start the evolution of a self-sustaining robotic industry. In time, he says, this approach could lead to the robotic colonization, or “robolonization,” of the solar system.

This might sound outlandish, Metzger says, but most of what we build in space doesn’t have to be as sophisticated as what we send from Earth. Because launch mass isn’t a concern, he says, “we can build a giant, clunky robot out of iron instead of a small, lightweight one out of titanium.” Truly advanced components, such as computer chips, could be shipped in batches and slotted into robots until they too could be manufactured in space. One of the key challenges, Metzger says, will be improving reliability. Lunar dust has a habit of getting into everything, and regular human repair missions can’t be expected.

RASSOR is not slated for launch, but another NASA team is preparing a flight-ready version of what could become the first equipment to extract and make resources on the moon: the Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE) experiment. RESOLVE is currently an experiment without a spacecraft, but NASA hopes to find a way to launch it on a rover as early as 2019. It is designed to hunt for hydrogen, which could possibly point the way to water ice. While in operation, RESOLVE will also attempt to make water, by heating lunar soil to 900 °C to release oxygen and combining it with hydrogen carried in from Earth.

For any harnessing of space resources to work, many experts say, the government will need to play a big role, creating infrastructure much as it might build a mail system or a network of highways or any other backbone of commerce. But that hasn’t stopped private companies from wading in. One of these is Planetary Resources, which is setting its sights on trips to near-Earth objects beginning in the early 2020s. On its first forays the company will search not for platinum and other pricey metals—the typical quarry of space mining outfits—but for water. The firm expects to extract it from some kinds of asteroids simply by using heat from concentrated sunlight, says Chris Lewicki, the company’s president and chief engineer. “Our focus isn’t necessarily on inventing new technology,” he says. “It’s on doing with a small team what once used to take the government.”

Gathering raw materials is only the beginning. To build up infrastructure, we must also develop ways to fabricate and manipulate structures in space.

The U.S. Defense Advanced Research Projects Agency has been making headlines with the Phoenix project, which would use advanced robotics and modular components to construct spacecraft in orbit. Among other uses, this combination could extract the antenna from a defunct satellite and build a new one around it.

A company called Tethers Unlimited, based in Bothell, Wash., hopes to fabricate structures from scratch, on even larger scales. Its project, called SpiderFab, aims to use robotic arms to build up and maneuver across 3-D–printed structures while floating free in orbit. The goal is to create objects that are too big to be folded into the top of a rocket. “What we’re trying to do is figure out how to make it not ridiculous to talk about antennas that are hundreds or thousands of meters in diameter,” says CEO Robert Hoyt. One of the biggest challenges Tethers is tackling now is how best to manage the thermal environment, Hoyt says. The temperature can vary by hundreds of degrees in orbit, and large temperature gradients could prevent structures from properly cooling and hardening, causing wild deformations.

The first 3-D printer to go into space won’t suffer such problems. Built by Made in Space, a start-up based in Moffett Field, Calif., and set to be delivered to the International Space Station later this year, it will be safely ensconced in a climate-controlled glove box. The printer makes objects out of heated polymer filament, just as many terrestrial 3-D printers do, but it has been altered to work in microgravity. The team logged hundreds of hours on parabolic flights to perfect the technology, says lead engineer Michael Snyder, but he won’t disclose what sets it apart from typical 3-D printers. “That’s our special sauce,” he says. The company plans to send an improved version of the printer to the station in 2015 and rent time on it to anyone who might want to print in space.

Both SpiderFab and Made in Space printers would require carrying material up from Earth to be used as the raw material for construction. Printing structures using material gathered elsewhere is still on the horizon. Although the European Space Agency, NASA, and others have looked into building very crude structures—mostly human habitats and landing pads—out of lunar soil, at present there are no plans to try out these ideas in space.

Still, many say the basic ingredients needed to build a true space infrastructure are more or less ready. Now we must find a way to combine them. Only then will our machines be able to prepare the way for our own forays to the moon, the planets, and the stars, turning us at last into a truly spacefaring species.


All hopes for space will come to nothing if the future resembles the present, with tight budgets and constantly changing plans. “I’ve been in the space business for 35 years,” says Paul Spudis, a scientist at the Lunar and Planetary Institute, in Houston. “I’ve never seen such a screwed-up mess as we now have.”

NASA’s current plans call for sending humans to Mars in the 2030s, but any such trip is at least 60 years away, argues Ralph McNutt, a physicist at Johns Hopkins University’s Applied Physics Laboratory, in Laurel, Md. “The price tags have come out to be so big that they’re just not palatable.” But Mars is easy for politicians to support, he says: They can advocate for the long-term goal without diverting enough funds today to make it happen.

Dithering could slowly eat away at public support. “I think the worst case would be if we continue only with these occasional piecemeal, individual missions that are kind of designed to be self-sustaining, like Conestoga wagons full of all the supplies you’ll ever need,” says Mason Peck, a professor of mechanical and aerospace engineering at Cornell and former chief technologist at NASA. “I think that will limit the amount of science that can be done and the amount of human exploration that we can do,” Peck adds. “If that persists, I think eventually people will lose patience, and there will be less and less public support for space exploration and science generally. Then we’ll never be able to get off the planet in a permanent way.”

But even if the government does push aggressively to build space infrastructure, the effort could still falter. A “killer app” that would vastly change the economic equation and make space development profitable still hasn’t been found. Scott Pace, director of the Space Policy Institute at George Washington University, in Washington, D.C., phrases the problem like a riddle: “What’s the question,” he asks, “for which space is the answer?”

There are also practical hurdles, such as the legality of claiming asteroids and lunar resources, says Henry Hertzfeld, a professor of space policy and international affairs at George Washington University. “Who has the rights? Do we have to divide them up, and if so, how? These issues would have to be addressed,” Hertzfeld says.

And if we somehow succeed in all our efforts, there could be side effects. For instance, we might spoil pristine environments of historical or scientific significance. Picking the path forward for space won’t be easy, but if we don’t carefully consider it, the choice could be made for us. —R.C.

Earth-eating suns can help us hunt life-friendly worlds

Distant stars that gobble up Earth-like planets are unlikely to be good hosts for life – after all, no one wants to share the neighbourhood with a world-devouring sun. Now astronomers have figured out how to identify the grizzly leftovers of a sun-like star's planetary feasting, which should make it easier to rule out planet-eaters and instead track down systems that still have habitable worlds.

Stars are mostly made up of hydrogen and helium, the fuel for nuclear fusion reactions that produce their heat and light. But they also can contain a spattering of other elements on their surfaces. Analysing starlight lets astronomers determine which elements are present in a star system, and gives clues to the kind of planets it contains.

To find out more, Keivan Stassun at Vanderbilt University in Nashville, Tennessee, and his colleagues used telescopes at the Las Campanas Observatory in Chile to look at a system containing a pair of sun-like stars called HD 20781 and HD 20782. The two stars formed from the same cloud of dust and gas, meaning they would initially have had the same chemical composition. Any differences must be down to their orbiting planets. Currently, we only see that one star has two Neptune-mass worlds and the other has a Jupiter-like planet.
Planet bullies

The team analysed the levels of 15 elements in both stars, including aluminium, silicon, calcium and iron, which make up the building blocks of Earth-like planets. Both stars had much higher levels of these elements than our own sun, suggesting they have absorbed large amounts of Earth-like material – an estimated 20 Earth masses for the first star and 10 Earth masses for the second.

This "heavy" material could not have come from dust and gas caught up by the stars as they formed, or it wouldn't show up on their surfaces. "The only way that we are able to detect this signature is if the rocky material was sprinkled on to the surface of the star later on," says Stassun.


It is likely that these rocky planets were bullied into the gaping maw of their stars by their bigger planetary brothers. HD 20781's Neptune-like planets orbit at around a fifth of the distance from the Earth to the sun, while HD 20782's Jupiter-mass planet is on an eccentric orbit that sometimes places it as close as 6 million kilometres from the star, or less than one per cent of the orbiting distance of our Jupiter. Stassun thinks that these massive planets originally formed further out but then migrated inwards, pushing any Earth-like worlds to their doom.
Rocky fingerprints

Hunting for exoplanets requires many years of careful observation, as telescopes such as NASA's Kepler mission have to watch for a planet to pass in front of its star multiple times. Measuring a star's chemical signature only takes one night, meaning systems unlikely to host life can be quickly ruled out. "The one that looks like it swallowed its Earths already is probably not the one to start with," says Stassun.

René Oudmaijer at the University of Leeds, UK, says looking at chemical signatures is a good idea that could potentially speed up the search for Earth-like exoplanets. "Astronomers don't want to waste their time," he says, but he cautions that the technique requires difficult and precise measurements. "The challenge will be to really identify that a star has the fingerprint of a planet that has been eaten up."

Skinny wormholes could send messages through time

Like some bizarre form of optical fibre, a long, thin wormhole might let you send messages through time using pulses of light.

Predicted by Einstein's general theory of relativity, wormholes are tunnels connecting two points in space-time. If something could traverse one, it would open up intriguing possibilities, such as time travel and instant communications.

But there's a problem: Einstein's wormholes are notoriously unstable, and they don't stay open long enough for anything to get through. In 1988, Kip Thorne at the California Institute of Technology and his colleagues speculated that wormholes could be kept open using a form of negative energy called Casimir energy.

Quantum mechanics tells us that the vacuum of space-time is teeming with random quantum fluctuations, which create waves of energy. Now imagine two metal plates sitting parallel in this vacuum. Some energy waves are too big to fit between the plates, so the amount of energy between them is less than that surrounding them. In other words, space-time between the plates has negative energy.
Slow collapse

Theoretical attempts to use such plates to keep wormholes open have so far proved untenable. Now Luke Butcher at the University of Cambridge may have found a solution.


"What if the wormhole itself could take the place of the plates?" he says. In other words, under the right circumstances, could the tube-like shape of the wormhole itself generate Casimir energy? His calculations show that if the wormhole's throat is orders of magnitude longer then the width of its mouth, it does indeed create Casimir energy at its centre.

"Unfortunately, this energy isn't enough to keep the wormhole stable. It will collapse," says Butcher. "But the existence of negative energy does allow the wormhole to collapse very slowly." Further rough calculations show that the wormhole's centre might remain open long enough to allow a pulse of light to get through.

A wormhole is a shortcut through space-time, so sending a light pulse through one could allow faster-than-light communication. And as the two mouths of a wormhole can exist at different points in time, in theory a message could be sent through time.

Butcher cautions that a lot more work is needed to confirm that other parts of the wormhole besides the centre remain open long enough for light to make it all the way through. He also needs to work out whether a pulse large enough to transmit meaningful information could sneak through the slowly collapsing throat. And, of course, we are a long way off translating the theoretical equations into a physical object.

"Does this mean we have the technology for building a wormhole?" asks Matt Visser at the Victoria University of Wellington in New Zealand. "The answer is still no." Still, he is intrigued by Butcher's work. "From a physics perspective, it may revitalise interest in wormholes."

          Mars InSight lander passes critical design review

NASA and its international partners now have the go-ahead to begin construction on a new Mars lander after it completed a successful Mission Critical Design Review on Friday.

NASA’s Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) mission will pierce beneath the Martian surface to study its interior. The mission will investigate how Earth-like planets formed and developed their layered inner structure of core, mantle and crust, and will collect information about those interior zones using instruments never before used on Mars.

InSight will launch from Vandenberg Air Force Base, on the central California coast near Lompoc, in March 2016. This will be the first interplanetary mission ever to launch from California. The mission will help inform the agency’s goal of sending a human mission to Mars in the 2030s.

InSight team leaders presented mission-design results last week to a NASA review board, which approved advancing to the next stage of preparation.

“Our partners across the globe have made significant progress in getting to this point and are fully prepared to deliver their hardware to system integration starting this November, which is the next major milestone for the project," said Tom Hoffman, InSight Project Manager of NASA's Jet Propulsion Laboratory (JPL), Pasadena, California. "We now move from doing the design and analysis to building and testing the hardware and software that will get us to Mars and collect the science that we need to achieve mission success."

To investigate the planet's interior, the stationary lander will carry a robotic arm that will deploy surface and burrowing instruments contributed by France and Germany. The national space agencies of France and Germany -- Centre National d’Etudes Spatiales (CNES) and Deutsches Zentrum für Luft- und Raumfahrt (DLR) -- are partnering with NASA by providing InSight's two main science instruments.

The Seismic Experiment for Interior Structure (SEIS) will be built by CNES in partnership with DLR and the space agencies of Switzerland and the United Kingdom. It will measure waves of ground motion carried through the interior of the planet, from "marsquakes" and meteor impacts. The Heat Flow and Physical Properties Package, from DLR, will measure heat coming toward the surface from the planet's interior.

"Mars actually offers an advantage over Earth itself for understanding how habitable planetary surfaces can form," said Bruce Banerdt, InSight Principal Investigator from JPL. "Both planets underwent the same early processes. But Mars, being smaller, cooled faster and became less active while Earth kept churning. So Mars better preserves the evidence about the early stages of rocky planets' development."

The three-legged lander will go to a site near the Martian equator and provide information for a planned mission length of 720 days -- about two years. InSight adapts a design from the successful NASA Phoenix Mars Lander, which examined ice and soil on far-northern Mars in 2008.

"We will incorporate many features from our Phoenix spacecraft into InSight, but the differences between the missions require some differences in the InSight spacecraft," said InSight Program Manager Stu Spath of Lockheed Martin Space Systems Company, Denver, Colorado. "For example, the InSight mission duration is 630 days longer than Phoenix, which means the lander will have to endure a wider range of environmental conditions on the surface."

Guided by images of the surroundings taken by the lander, InSight's robotic arm will place the seismometer on the surface and then place a protective covering over it to minimize effects of wind and temperature on the sensitive instrument. The arm will also put the heat-flow probe in position to hammer itself into the ground to a depth of 3 to 5 yards (2.7 to 4 1/2 meters).

Another experiment will use the radio link between InSight and NASA's Deep Space Network antennas on Earth to precisely measure a wobble in Mars' rotation that could reveal whether Mars has a molten or solid core. Wind and temperature sensors from Spain's Centro de Astrobiologia and a pressure sensor will monitor weather at the landing site, and a magnetometer will measure magnetic disturbances caused by the Martian ionosphere.

InSight's international science team is made up of researchers from Austria, Belgium, Canada, France, Germany, Japan, Poland, Spain, Switzerland, the United Kingdom and the United States. JPL manages InSight for NASA's Science Mission Directorate, Washington. InSight is part of NASA's Discovery Program of competitively selected missions. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program. Lockheed Martin will build the lander and other parts of the spacecraft at its Littleton, Colorado, facility near Denver.

NASA, private group sign agreement to revive old spacecraft

A dormant spacecraft will swing past Earth in August, and private space flight enthusiasts have plans to put it back to work.

The International Sun/Earth Explorer 3 (ISEE-3) was a joint US and European spacecraft launched in 1978. It was initially deployed to the L1 Lagrange point, a spot between the sun and Earth where the combined gravitational forces of the two massive objects effectively holds smaller objects in place. From this vantage point, the spacecraft studied how charged particles from the sun, called the solar wind, interact with our planet's magnetic field.

In the mid-1980s the spacecraft also had a career as a comet chaser: It was sent into orbit around the sun and directed to pass through the tails of comets Giacobini-Zinner and Halley, collecting data on their composition. The spacecraft was ordered to shut down in 1997.
Radio contact

But it seems someone forgot to flip the switch. Surprisingly, in 2008, the international Deep Space Network made contact with ISEE-3 and showed that it was still able to operate. NASA was interested in reusing it but couldn't spare the funds.


Dennis Wingo of California-based aerospace firm Skycorp and Keith Cowing of space news site NASA Watch have raised more than $130,000 through online crowdfunding. In an unprecedented partnership with NASA, the team made first contact with ISEE-3 on 19 May with the Arecibo radio telescope in Puerto Rico.

They hope to order the craft to fire its engines in a few weeks and enter orbit near Earth, where it could provide solar wind data usable by the general public and the research community.

Watch two neutron stars rip each other apart to form a black hole

                        

This supercomputer simulation shows one of the most violent events in the universe: a pair of neutron stars colliding, merging and forming a black hole. A neutron star is the compressed core left behind when a star born with between eight and 30 times the sun’s mass explodes as a supernova. Neutron stars pack about 1.5 times the mass of the sun — equivalent to about half a million Earths — into a ball just 12 miles (20 km) across.

As the simulation begins, we view an unequally matched pair of neutron stars weighing 1.4 and 1.7 solar masses. They are separated by only about 11 miles, slightly less distance than their own diameters. Redder colors show regions of progressively lower density.

As the stars spiral toward each other, intense tides begin to deform them, possibly cracking their crusts. Neutron stars possess incredible density, but their surfaces are comparatively thin, with densities about a million times greater than gold. Their interiors crush matter to a much greater degree densities rise by 100 million times in their centers. To begin to imagine such mind-boggling densities, consider that a cubic centimeter of neutron star matter outweighs Mount Everest.

By 7 milliseconds, tidal forces overwhelm and shatter the lesser star. Its superdense contents erupt into the system and curl a spiral arm of incredibly hot material. At 13 milliseconds, the more massive star has accumulated too much mass to support it against gravity and collapses, and a new black hole is born. The black hole’s event horizon — its point of no return — is shown by the gray sphere. While most of the matter from both neutron stars will fall into the black hole, some of the less dense, faster moving matter manages to orbit around it, quickly forming a large and rapidly rotating torus. This torus extends for about 124 miles (200 km) and contains the equivalent of 1/5th the mass of our sun.

Scientists think neutron star mergers like this produce short gamma-ray bursts (GRBs). Short GRBs last less than two seconds yet unleash as much energy as all the stars in our galaxy produce over one year.

The rapidly fading afterglow of these explosions presents a challenge to astronomers. A key element in understanding GRBs is getting instruments on large ground-based telescopes to capture afterglows as soon as possible after the burst. The rapid notification and accurate positions provided by NASA’s Swift mission creates a vibrant synergy with ground-based observatories that has led to dramatically improved understanding of GRBs, especially for short bursts.

 Astronomers create "realistic" simulation of universe on a                                                supercomputer

                     

The team recreated one of the most iconic images in astronomy: the Hubble eXtreme Deep Field. The mock observations are on the right side, whereas the real observations are on the left side. One side flows into the other, showing how powerful these simulations are.Illustris -

The light we see from distant galaxies takes millions to billions of years to reach us, allowing astronomers to study the universe in its infancy. But while advancements with the Hubble Space Telescope and others have shed light on our origins, a detailed understanding of the evolution of the universe through observations alone is a rather daunting task.

So researchers use advanced computer simulations to create their own mini-universes. By unleashing the laws of physics within supercomputers, they can study the universe’s evolution and match simulated galaxies to those observed in the real universe.

Now, researchers have created the most realistic computer simulation to date. It’s the first to simultaneously predict both large-scale observations — the network of filaments that span massive galaxy clusters — and small-scale observations — the detailed gas and stellar content within galaxies.

“The novelty of our model lies in the combination of the physical size of the simulated universe, the details we resolve inside it, and the accuracy with which we model the key physical processes that shape the large-scale structure and [smaller] galaxies in the universe,” says coauthor Shy Genel (Harvard-Smithsonian Center for Astrophysics).

The Universe in a Box

                           

 A view through the Illustris simulation of the present-day universe (z=0), about 70 million light-years deep, centered on the most massive cluster. This view shows dark matter density on the left and gas density on the right.Illustris Collaboration 

The researchers began their model from initial conditions resembling the very young universe 12 million years after the Big Bang. They then unleashed complex physical laws — the gravitational pull of matter, the chemical processes in diffuse gas, radiation and magnetic fields, as well as the physics of star and black hole formation— onto their simulation, allowing it to evolve for 13 billion years.

Accounting for normal matter and the complex physical laws surrounding this matter allowed the team to take their models a huge leap forward. Previous simulations had accounted primarily for dark matter, severely limiting their potential to match observations.

The team found their results matched the observable universe remarkably well. Surprisingly, the authors found that including supernova explosions and super-massive black holes in their calculations was crucial to obtaining a model galaxy population that resembled real galaxies.

They were able to reproduce a wide range of observable properties, including the present day ratio of the amount of stars to dark matter for galaxies of all masses. So while huge uncertainties remain regarding the nature of dark matter and dark energy, the simulation clears a number of the hurdles facing the standard cosmological model — which posits that these mysterious entities constitute the bulk of the universe’s content.

This "motivates us further to continue searching for the elusive dark matter and dark energy to understand their true nature,” says Genel.

A big challenge for dark matter simulations has been recreating the variety of galaxies we observe in our universe. The Illustris simulation succeeded in producing spiral galaxies like our own Milky Way. But, like previous simulations, it still struggled to produce realistic low-mass galaxies. These smaller galaxies formed far too early in the simulation, ending up with prematurely aged stellar populations — stars two to three times older than what observations show. Forming low-mass galaxies remains an unsolved problem.

A Model to Mine for Years to Come

Illustris's simulated volume contains 41,416 galaxies covering a wide range of masses, shapes, and sizes. It’s only a pie slice of the cosmos, but it required supercomputers in France, Germany and the U.S. Had the researchers used a single desktop, the simulation would have needed to run for 500,000 years.

“Our model universe is so large and so detailed that it takes about half a petabyte (1000 terabyte) of data to describe it,” says Genel. “We, and other astronomers across the community, will mine these data for years in order to learn about almost every aspect of galaxy formation. Understanding galaxy formation is a big endeavor that will eventually allow us to understand the origin of our own Milky Way galaxy, as well as its fate in the future.”

Image Credit: NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring

The effects of climate change on Earth can be seen clearly in photos taken by satellites in space, and those images are vital tools in protecting our home planet, NASA chief Charles Bolden wrote today (May 6).

Bolden's comments, which were released on his NASA blog, followed the release of the Third U.S. National Climate Assessment report today by the White House. According to the report, the fallout from human-induced climate change will result in more extreme weather events, longer and hotter summers and other extreme regional effects. Some of those effects, like more frequent wildfires and coastal flooding, are visible from space.

"We can already see the impacts of climate change around the world, especially through the lens of our satellites," Bolden wrote in the blog post today. "The U.S. National Climate Assessment combined observations from NASA's incredible fleet of Earth observation satellites with surface-based and satellite data from our interagency and international partners, to help us understand what’s going on globally in areas such as polar ice, precipitation extremes, temperature change, sea level rise and forest ecosystems.

Bolden wrote that NASA scientists and missions were vital to the National Climate Assessment report, and the space agency has big plans in 2014 to continue that role.

"Five NASA Earth Science missions will be launched into space in 2014 alone," Bolden wrote. "Together with NASA’s existing fleet of satellites, airborne missions, researchers, and the unique platform of the International Space Station (ISS), these new missions will help answer some of the critical challenges facing our planet today and in the future."

In February, NASA and Japan launched the Global Precipitation Measurement core observatory to track global rainfall patterns. The next satellite to launch will be the Orbiting Carbon Observatory 2, which is slated to blast off in July to map the carbon dioxide in Earth's atmosphere. It is a replacement for the first OCO satellite, which was lost during a failed launch in 2009.

Two of the new climate-monitoring NASA instruments will be delivered to the International Space Station. The RapidScat instrument will monitor ocean wind speeds and direction, while the Cloud-Aerosol Transport System will use light-detection and ranging (or lidar) to track dust, smoke and other particles in Earth's atmosphere.

Finally, NASA will launch the Soil Moisture Active Passive mission in November to study soil moisture around the world, as well as monitor the timing of freeze thaws.

"All of the data NASA collects is widely disseminated and helps many people to make wise decisions about how we care for our planet, as well as predict and cope with changes in climate and extreme weather events," Bolden wrote. "The National Climate Assessment is an example of how critical the NASA data and research are."

Image Credit: NASA

The United States and Russia, along with the other partners of the International Space Station (ISS) community, have been working together successfully for 14 years. As NASA Administrator Charlie Bolden has noted, this relationship has survived many political crises in that period, and the communities of engineers, scientists and astronauts have also worked well together. The Russian space program has been and currently remains a highly capable, cost-effective, reliable partner for U.S. interests on the ISS.

While no one has ever doubted the importance of an independent U.S. capability to put its own astronauts in space, NASA's budget could not keep the space shuttle flying while simultaneously allowing for the development of new systems. So, the United States has been living through an expected gap of about five years from the retirement of the space shuttle, waiting until multiple, new U.S. human spaceflight capabilities become available. Those developments are going quite well, and the nation should soon have several ways to send American astronauts on American vehicles to the International Space Station , and even to points far beyond any previous human missions.

However, Americans are now seeing just how critical an independent capability is. With the United States ratcheting up sanctions on Russia, now including their aerospace sector, it is all too obvious how much this country's space program depends on Russia. Some of our main satellite launch systems depend on powerful engines built in and sourced from Russia. Without these specific systems, some important U.S. satellite launch systems might soon be grounded. In addition, NASA needs to ferry U.S. astronauts both up to and back from the ISS. Without the Soyuz, crews could literally be stranded on board the ISS, or prevented from returning to the ISS from the ground.

The private sector has multiple U.S. human spaceflight systems for low-Earth orbit in development at this time, including Sierra Nevada's Dream Chaser space plane, Boeing's CST- 100 capsule and Space X's Falcon 9 rocket and Dragon spacecraft. Additionally, NASA has its own Orion crew exploration vehicle. But of these four, the only one that has already been flying cargo to the ISS is Falcon 9/Dragon. Even with a well-coordinated and financially supported hard push, these systems are 18 to 24 months away from being ready to fly human crews to the ISS. Without a government-mandated effort, it could be considerably longer!

After more than two decades of development, it is essential that the United States keeps the ability to visit, work and return from the ISS within its national capabilities. Yet, it is surprising to see how little discussion, much less pressure, is being applied to accelerating plans to regain an independent capability for human spaceflight. Now seems to be the time for Congress, NASA and the general public to all push hard, and get one or more of these U.S. systems in space as soon as possible.