Back to the Future — Serviceable Spacecraft Make a Comeback

NASA Goddard Technologists Find Solutions
Ever wonder about the future of space science? Hop inside a time machine that transports you back 40 years and you may get a good idea about where things are headed. History, it would seem, has a funny way of repeating itself.

Goddard engineer Michael Kienlen, who is studying servicing beyond low-Earth orbit, and Benjamin Reed, deputy project manager of Goddard’s Satellite Servicing Capabilities Office, stand in front of a mockup of the Robotic Refueling Mission now deployed on the International Space Station.
Credits: NASA/C. Gunn

Serviceable spacecraft — like the NASA-developed Multi-Mission Modular Spacecraft (MMS) and, of course, the iconic Hubble Space Telescope that NASA conceived and developed in the 1970s with servicing in mind — are once again de rigueur. (The serviceable MMS shouldn’t be confused with NASA’s Magnetospheric Multiscale mission, which also goes by the MMS acronym.)
Case in point: As required by Congress in a law passed in 2010 and then amended five years later, NASA is requiring that proposed flagship astrophysics missions support servicing, even if their orbits are up to a million miles away. The agency also released a Request for Information (RFI) seeking ideas for a spacecraft design that it could use for both its proposed Asteroid Redirect Mission (ARM) and as a vehicle for refueling a government satellite in low-Earth orbit.
“The 40-year cycle is starting all over again,” said Benjamin Reed, deputy project manager of the Satellite Servicing Capabilities Office (SSCO) at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. SSCO personnel developed all of the technologies to service Hubble and is now creating and demonstrating next-generation servicing technologies, including validation experiments on the International Space Station. “It worked with Hubble. It would be crazy not to think it would work again. It’s back to the future.”
And according to him, NASA is well along the way to realizing that future — even if it means servicing spacecraft positioned tens of thousands of miles away from terra firma.
What’s Different Today
Satellite servicing certainly isn’t new — as evidenced by the five Hubble servicing missions and the 1984 repair of the Solar Max mission that used the MMS serviceable satellite bus.
What’s different today is where these operations are expected to occur in the future and the technology needed to ensure success. Robotic spacecraft — likely operated with joysticks by technicians on the ground — would carry out the hands-on maneuvers, not human beings using robotic and other specialized tools, as was the case for low-Earth-orbiting Hubble and Solar Max.
“Goddard knows how to service satellites in low-Earth orbits,” said Michael Kienlen, an SSCO engineer who is studying servicing beyond low-Earth orbit. “However, future flagship missions, including the WFIRST-AFTA (Wide-Field Infrared Survey Telescope-Astrophysics Focused Telescope) and other future observatories should operate in more distant orbits.”

The Satellite Servicing Capabilities Office is developing technologies needed to repair and service satellites not originally designed for servicing. The organization uses laboratory equipment, such as this mockup of Landsat 7, to test the techniques.
Credits: NASA/C. Gunn

WFIRST-AFTA, which NASA plans to equip with an 8-foot (2.4-meter) mirror and a slitless spectrometer and imager, will study dark energy, the mysterious form of energy that permeates all of space and accelerates the expansion of the universe, while providing cosmic surveys. It also will carry a coronagraph that will allow the observatory to image giant exoplanets and debris disks in other solar systems.
Other conceptual missions that various groups currently are studying in preparation for the 2020 Astrophysics Decadal Survey also could operate in more distant orbits.
Although still in the conceptual stage, these missions may carry very large primary mirrors that would allow scientists to study cosmological targets with greater resolution and sensitivity. One possible scientific objective would be to find Earth-size exoplanets [This links to the story about the VNC] in the habitable zone in our solar neighborhood and then identify chemicals in their atmospheres that may indicate the presence of life.
To achieve these ambitious goals, WFIRST and the other conceptual observatories ideally would operate from Sun-Earth L2 (SEL2), a thermally stable sun-Earth orbit roughly a million miles away.
Due to concerns that technologies might not exist to service SEL2-orbiting missions, some have recommended that the observatories fly in geostationary orbit (GEO), roughly 10 percent of the distance to the moon.
Robotic Servicing Achievable in SEL2
“GEO may not an option for these missions because of the thermal-stability requirements,” Kienlen said. “One stumbling block is the perception that there is not a plausible scenario for servicing satellites at SEL2. We don’t want to force all future flagship missions to a lesser-performing orbit because they are required to be serviceable. So, we will figure out how to take servicing to them.”
“It’s not like we have to reinvent the wheel. We have never stopped developing servicing technologies. The difference today is that future flagship missions are required to be serviceable,” added Julie Crooke, a Goddard engineer, astrophysics technical manager, and member of a team that has been studying one of several future mission concepts. “With appropriate technology investments, we are on a clear path to demonstrating a servicing capability far from low-Earth orbit,” she said.
Beth Keer, who heads SSCO’s Advanced Concepts Office, agrees. “We have demonstrated robotic refueling on the space station. It’s one of the stepping stones along the way to making robotic servicing the way of the future.”
Robotic Refueling
Now in the second phase of its on-orbit demonstration aboard the International Space Station, NASA’s Robotic Refueling Mission (RRM) is using the Canadian Space Agency’s two-armed robotic handyman, Dextre, to show how future robots could service and refuel satellites in space.

VIPIR, short for Visual Inspection Poseable Invertebrate Robot, is a robotic, articulating borescope that would help mission operators who need robotic eyes to troubleshoot anomalies, investigate micrometeoroid strikes, and carry out teleoperated satellite-repair jobs. NASA successfully demonstrated VIPIR’s capabilities earlier this year.
Credits: NASA/C. Gunn

One of those tools, VIPIR, short for Visual Inspection Poseable Invertebrate Robot, is a robotic, articulating borescope equipped with a second motorized, zoom-lens camera that would help mission operators who need robotic eyes to troubleshoot anomalies, investigate micrometeoroid strikes, and carry out teleoperated satellite-repair jobs. NASA successfully demonstrated VIPIR’s capabilities earlier this year. During RRM’s third phase, the SSCO team plans to demonstrate the transfer of xenon, a colorless, dense noble gas potentially useful for powering ion engines.
RRM, however, is only one piece of SSCO’s ongoing efforts to making servicing a tried-and-true capability for future missions.
ROSE and Restore
To be easily serviceable, regardless of its orbit, the satellite itself must be specially designed to accommodate repairs. For example, NASA’s MMS serviceable satellite bus featured a modular design that made it easy for astronauts to install a new attitude control system when the original failed on Solar Max.
Though not modular like MMS, Hubble did support on-orbit servicing on a component level. Like opening a door, astronauts literally would pull out an instrument before reinserting the new one into the same cavity — a job made easier with the observatory’s 76 handholds. However, Hubble’s lack of modularity meant that NASA had to develop special tools and procedures specifically for nearly each component and task.
“Although Hubble servicing was extremely successful, the missions were complex and required a highly orchestrated combination of robotic and astronaut activities,” observed Dino Rossetti, of Conceptual Analytics in Glen Dale, Maryland, in a paper submitted at an American Institute of Aeronautics and Astronautics conference in September.
Modularity is key, and SSCO is taking it to a new level, Keer said.
The organization now is developing the Reconfigurable Operational spacecraft for Science and Exploration (ROSE), a low-cost spacecraft concept that seeks to build on the success of MMS. The organization’s overriding goal is long-term affordability and servicing at a system level, which would make ROSE highly flexible for medium-size missions, Keer said.
“We view ROSE as a pathfinder for future missions,” Reed added.
Repair Craft Needed
Also needed is a robotic servicing vehicle. Reed said his organization has focused on developing that capability, as well. For the past few years, the organization has pursued a notional mission called Restore, which would be capable of refueling satellites in both geostationary and low-Earth orbits.
Key servicing technologies, he said, are baselined for NASA’s proposed asteroid mission, ARM, which involves the capture of a large boulder from the surface of a near-Earth asteroid and moving it into a stable orbit around the moon for astronaut exploration. The same type of spacecraft also could refuel a government satellite in low-Earth orbit, as called for in NASA’s RFI.
“I can imagine a fleet of Restores,” Reed said. “A single servicer could refuel and service WFIRST and another future observatory at the SEL2 orbit. Another could be parked in another orbit for other servicing tasks, such as helping assemble a 65-foot segmented mirror in space, he said.
“We’re taking all we learned over the past many years, robots and humans working together,” Keer added. “Our attitude here is you have to have one foot in the future. We expect to be on the cutting edge. Servicing at more distant orbits, such as SEL2, is coming,” she said.
Source: NASA

Researchers Catch Comet Lovejoy Giving Away Alcohol

Comet Lovejoy lived up to its name by releasing large amounts of alcohol as well as a type of sugar into space, according to new observations by an international team. The discovery marks the first time ethyl alcohol, the same type in alcoholic beverages, has been observed in a comet. The finding adds to the evidence that comets could have been a source of the complex organic molecules necessary for the emergence of life.

Picture of the comet C/2014 Q2 (Lovejoy) on 12 February 2015 from 50km south of Paris.
Credits: Fabrice Noel

“We found that comet Lovejoy was releasing as much alcohol as in at least 500 bottles of wine every second during its peak activity,” said Nicolas Biver of the Paris Observatory, France, lead author of a paper on the discovery published Oct. 23 in Science Advances. The team found 21 different organic molecules in gas from the comet, including ethyl alcohol and glycolaldehyde, a simple sugar.
Comets are frozen remnants from the formation of our solar system. Scientists are interested in them because they are relatively pristine and therefore hold clues to how the solar system was made. Most orbit in frigid zones far from the sun. However, occasionally, a gravitational disturbance sends a comet closer to the sun, where it heats up and releases gases, allowing scientists to determine its composition.

Picture of the comet C/2014 Q2 (Lovejoy) on 22 February 2015
Credits: Fabrice Noel

Comet Lovejoy (formally cataloged as C/2014 Q2) was one of the brightest and most active comets since comet Hale-Bopp in 1997. Lovejoy passed closest to the sun on January 30, 2015, when it was releasing water at the rate of 20 tons per second. The team observed the atmosphere of the comet around this time when it was brightest and most active. They observed a microwave glow from the comet using the 30-meter (almost 100-foot) diameter radio telescope at Pico Veleta in the Sierra Nevada Mountains of Spain.

The IRAM 30-meter radio telescope
Credits: Nicolas Biver

Sunlight energizes molecules in the comet’s atmosphere, causing them to glow at specific microwave frequencies (if microwaves were visible, different frequencies would be perceived as different colors). Each kind of molecule glows at specific, signature frequencies, allowing the team to identify it with detectors on the telescope. The advanced equipment was capable of analyzing a wide range of frequencies simultaneously, allowing the team to determine the types and amounts of many different molecules in the comet despite a short observation period.
Some researchers think that comet impacts on ancient Earth delivered a supply of organic molecules that could have assisted the origin of life. Discovery of complex organic molecules in Lovejoy and other comets gives support to this hypothesis.
“The result definitely promotes the idea the comets carry very complex chemistry,” said Stefanie Milam of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, a co-author on the paper. “During the Late Heavy Bombardment about 3.8 billion years ago, when many comets and asteroids were blasting into Earth and we were getting our first oceans, life didn’t have to start with just simple molecules like water, carbon monoxide, and nitrogen. Instead, life had something that was much more sophisticated on a molecular level. We’re finding molecules with multiple carbon atoms. So now you can see where sugars start forming, as well as more complex organics such as amino acids — the building blocks of proteins — or nucleobases, the building blocks of DNA. These can start forming much easier than beginning with molecules with only two or three atoms.”
In July, the European Space Agency reported that the Philae lander from its Rosetta spacecraft in orbit around comet 67P/Churyumov­-Gerasimenko detected 16 organic compounds as it descended toward and then bounced across the comet’s surface. According to the agency, some of the compounds detected play key roles in the creation of amino acids, nucleobases, and sugars from simpler “building-block” molecules.
Astronomers think comets preserve material from the ancient cloud of gas and dust that formed the solar system. Exploding stars (supernovae) and the winds from red giant stars near the end of their lives produce vast clouds of gas and dust. Solar systems are born when shock waves from stellar winds and other nearby supernovae compress and concentrate a cloud of ejected stellar material until dense clumps of that cloud begin to collapse under their own gravity, forming a new generation of stars and planets.
These clouds contain countless dust grains. Carbon dioxide, water, and other gases form a layer of frost on the surface of these grains, just as frost forms on car windows during cold, humid nights. Radiation in space powers chemical reactions in this frost layer to produce complex organic molecules. The icy grains become incorporated into comets and asteroids, some of which impact young planets like ancient Earth, delivering the organic molecules contained within them.
“The next step is to see if the organic material being found in comets came from the primordial cloud that formed the solar system or if it was created later on, inside the protoplanetary disk that surrounded the young sun,” said Dominique Bockelée-Morvan from Paris Observatory, a co-author of the paper.
Milam was funded by a grant from the NASA Planetary Astronomy Program. The team included researchers from the Paris Observatory, CNRS (Centre National de la Recherche Scientifique, Paris), PSL Research University (Paris Sciences et Lettres, Paris), Bordeaux Observatory, France, IRAM (Institut de Radioastronomie Millimétrique, Grenoble, France) and Stockholm Observatory, Stockholm, Sweden, as well as from NASA. The 30-meter telescope used to make the team’s observations is operated by IRAM, a collaboration among France, Germany, and Spain. IRAM is supported by INSU (Institut National des Sciences de l’univers)/CNRS (France), MPG (Max-Planck-Gesellschaft zur Förderung der Wissenschaften e. V.) (Germany), and IGN (Instituto Geográfico Nacional) (Spain).
Source: NASA

What’s Orbiting KIC 8462852 – Shattered Comet or Alien Megastructure?

Posted Yesterday

“Bizarre.” “Interesting.” “Giant transit”.  That were the reactions of Planet Hunters project volunteers when they got their first look at the light curve of the otherwise normal sun-like star KIC 8462852 nearly.

Something other than a transiting planet makes KIC 8462852 fluctuate wildly and unpredictably in brightness. Astronomers suspect a crumbled comet, but the cause remains a mystery. Credit: NASA

Of the more than 150,000 stars under constant observation during the four years of NASA’s primary Kepler Mission (2009-2013), this one stands alone for the inexplicable dips in its light. While almost certainly naturally-caused, some have suggested we consider other possibilities.

Kepler-11, a sun-like star orbited by six planets. At times, two or more planets pass in front of the star at once, as shown in this artist’s conception of a simultaneous transit of three planets observed by the Kepler spacecraft on Aug. 26, 2010. During each pass or transit, the star’s light fades in a periodic way. Credit: NASA/Tim Pyle

You’ll recall that the orbiting Kepler observatory continuously monitored stars in a fixed field of view focused on the constellations Lyra and Cygnus hoping to catch  periodic dips in their light caused by transiting planets. If a drop was seen, more transits were observed to confirm the detection of a new exoplanet.
And catch it did. Kepler found 1,013 confirmed exoplanets in 440 star systems as of January 2015 with 3,199 unconfirmed candidates. Measuring the amount of light the planet temporarily “robbed” from its host star allowed astronomers to determine its diameter, while the length of time between transits yielded its orbital period.

Graph showing the big dip in brightness of KIC 8462852 around 800 days (center) followed after 1500 days whole series of dips of varying magnitude up to 22%. The usual drop in light when an exoplanet transits its host star is a fraction of a percent. The star’s normal brightness has been set to “1.00” as a baseline. Credit: Boyajian et. all

Volunteers with the Planet Hunters project, one of many citizen science programs under the umbrella of Zooniverse, harness the power of the human eye to examine Kepler light curves (a graph of a star’s changing light intensity over time), looking for repeating patterns that might indicate orbiting planets. They were the first to meet up with the perplexing KIC 8462852.

A detailed look at a small part of the star’s light curve reveals an unknown, regular variation of its light every 20 days. Superimposed on that is the star’s 0.88 day rotation period. Credit: Boyajian et. al

This magnitude +11.7 star in Cygnus, hotter and half again as big as the Sun, showed dips all over the place. Around Day 800 during Kepler’s run, it faded by 15% then resumed a steady brightness until Days 1510-1570, when it underwent a whole series of dips including one that dimmed the star by 22%. That’s huge! Consider that an exo-Earth blocks only a fraction of a percent of a star’s light; even a Jupiter-sized world, the norm among extrasolar planets, soaks up about a percent.
Exoplanets also show regular, repeatable light curves as they enter, cross and then exit the faces of their host stars. KIC 8462852’s dips are wildly a-periodic.

Could a giant comet breakup and subsequent cascading breakups of those pieces be behind KIC 8462852’s erratic changes in brightness? Credit: NASA

Whatever’s causing the flickering can’t be a planet. With great care, the researchers ruled out many possibilities: instrumental errors, starspots (like sunspots but on other stars), dust rings seen around young, evolving stars (this is an older star) and pulsations that cover a star with light-sucking dust clouds.
What about a collision between two planets? That would generate lots of material along with huge clouds of dust that could easily choke off a star’s light in rapid and irregular fashion.
A great idea except that dust absorbs light from its host star, warms up and glows in infrared light. We should be able to see this “infrared excess” if it were there, but instead KIC 8462852 beams the expected amount of infrared for a star of its class and not a jot more. There’s also no evidence in data taken by NASA’s Wide-field Infrared Survey Explorer (WISE) several years previously that a dust-releasing collision happened around the star.

Our featured star shines at magnitude +11.7 in the constellation Cygnus the Swan (Northern Cross) high in the southern sky at nightfall this month. A 6-inch or larger telescope will easily show it. Use this map to get oriented and the map below to get there. Source: Stellarium

After examining the options, the researchers concluded the best fit might be a shattered comet that continued to fragment into a cascade of smaller comets. Pretty amazing scenario. There’s still dust to account for, but not as much as other scenarios would require.

Detailed map showing stars to around magnitude 12 with the Kepler star identified. It’s located only a short distance northeast of the open cluster NGC 6886 in Cygnus. North is up. Click to enlarge. Source: Chris Marriott’s SkyMap

Being fragile types, comets can crumble all by themselves especially when passing exceptionally near the Sun as sungrazing comets are wont to do in our own Solar System. Or a passing star could disturb the host star’s Oort comet cloud and unleash a barrage of comets into the inner stellar system. It so happens that a red dwarf star lies within about 1000 a.u. (1000 times Earth’s distance from the Sun) of KIC 8462852. No one knows yet whether the star orbits the Kepler star or happens to be passing by. Either way, it’s close enough to get involved in comet flinging.
So much for “natural” explanations. Tabetha Boyajian, a postdoc at Yale, who oversees the Planet Hunters and the lead author of the paper on KIC 8462852, asked Jason Wright, an assistant professor of astronomy at Penn State, what he thought of the light curves. “Crazy” came to mind as soon he set eyes on them, but the squiggles stirred a thought. Turns out Wright had been working on a paper about detecting transiting megastructures with Kepler.

There are Dyson rings and spheres and a Dyson swarm depicted here. Could this or a variation of it be what we’re seeing around KIC 8462852? Not likely, but a fun thought experiment. Credit: Wikipedia

In a recent blog, he writes: “The idea is that if advanced alien civilizations build planet-sized megastructures — solar panels, ring worlds, telescopes, beacons, whatever — Kepler might be able to distinguish them from planets.” Let’s assume our friendly aliens want to harness the energy of their home star. They might construct enormous solar panels by the millions and send them into orbit to beam starlight down to their planet’s surface. Physicist Freeman Dyson popularized the idea back in the 1960s. Remember the Dyson Sphere, a giant hypothetical structure built to encompass a star?
From our perspective, we might see the star flicker in irregular ways as the giant panels circled about it. To illustrate this point, Wright came up with a wonderful analogy:
“The analogy I have is watching the shadows on the blinds of people outside a window passing by. If one person is going around the block on a bicycle, their shadow will appear regularly in time and shape (like a regular transiting planet). But crowds of people ambling by — both directions, fast and slow, big and large — would not have any regularity about it at all.  The total light coming through the blinds might vary like — Tabby’s star.”

The Green Bank Telescope is the world’s largest, fully-steerable telescope. The GBT’s dish is 100-meters by 110-meters in size, covering 2.3 acres of space. Credit: NRAO/AUI/NSF

Even Wright admits that the “alien hypothesis” should be seen as a last resort. But to make sure no stone goes  unturned, Wright, Boyajian and several of the Planet Hunters put together a proposal to do a radio-SETI search with the Green Bank 100-meter telescope. In my opinion, this is science at its best. We have a difficult question to answer, so let’s use all the tools at our disposal to seek an answer.

KIC 8462852, photographed on Oct. 15, 2015. It’s an F3 V star (yellow-white dwarf) located about 1,480 light years from Earth. Credit: Gianluca Masi

In the end, it’s probably not an alien megastructure, just like the first pulsar signals weren’t sent by LGM-1 (Little Green Men). But whatever’s causing the dips, Boyajian wants astronomers to keep a close watch on KIC 8462852 to find out if and when its erratic light variations repeat. I love a mystery, but  answers are even better.
Source: Universe Today, written by Bob King

Earth's Gravitational Pull Cracks Open the Moon

by Charles Q. Choi, Live Science Contributor   |   October 13, 2015 11:54am ET

Lunar Reconnaissance Orbiter Camera images have revealed thousands of young, lobate thrust fault scarps on the moon. Image released Sept. 15, 2015. Credit: NASA/LRO/Arizona State University/Smithsonian Institution View full size image

Earth's gravitational pull is massaging the moon, opening up faults in the lunar crust, researchers say.
Just as the moon's gravitational pull causes seas and lakes to rise and fall as tides on Earth, the Earth exerts tidal forces on the moon. Scientists have known this for a while, but now they've found that Earth's pull actually opens up faults on the moon.
"We know the close relationship between the Earth and the moon goes back to their origins, but what a surprise [it was] to find the Earth is still helping to shape the moon," study lead author Thomas Watters, a planetary scientist at the Smithsonian Institution's National Air and Space Museum in Washington, D.C., told Space.com. [The Moon: 10 Surprising Lunar Facts]

The researchers analyzed data from NASA's Lunar Reconnaissance Orbiter (LRO), which launched in 2009. In 2010, the spacecraft helped scientists discover that the moon is shrinking: High-resolution LRO images revealed 14 lobe-shaped fault scarps, or cliffs, which likely formed as the hot interior of the moon cooled and contracted, forcing the solid crust to buckle.

The map shows the locations of over 3,200 lobate thrust fault scarps (red lines) on the Moon.
Credit: NASA/LRO/Arizona State University/Smithsonian Institution

View full size image

After more than six years in orbit and imaging nearly three-quarters of the moon's surface, LRO has detected more than 3,200 of these fault scarps. These cliffs are the most common tectonic feature on the moon, and are typically dozens of yards or meters high and less than about 6 miles (10 kilometers) long. Previous research had suggested they were less than 50 million years old, and are likely still actively forming today.
If the only influence on lunar fault scarp formation was the cooling of the moon's interior, the orientations of these cliffs should be random, because the forces of contraction would be equal in strength in all directions, researchers said.

Lunar Reconnaissance Orbiter Camera images (LROC) revealed thousands of lobate fault scarps on the moon, including this prominent one in the Vitello Cluster. Image released Sept. 15, 2015.
Credit: NASA/LRO/Arizona State University/Smithsonian Institution

View full size image

"It was a big surprise to find that the fault scarps don't have random orientations," Watters said.
Instead, "there is a pattern in the orientations of the thousands of faults, and it suggests something else is influencing their formation, something that's also acting on a global scale," Watters said in a statement. "That something is the Earth's gravitational pull."
Earth's tidal forces do not act equally across the surface of the entire moon. Instead, they act most strongly on the parts of the moon that are either closest to or farthest away from Earth. The result is that many scarps are lined up north to south at low and mid latitudes near the moon's equator and east to west at high latitudes near the moon's poles.
The effects of Earth's tidal forces are likely about 50 to 100 times smaller than those from the moon's contraction, Watters said. A model incorporating the effects of tidal and contractional forces on the moon's surface closely matched the fault scarps observed on the moon, he added.
"With LRO, we've been able to study the moon globally in detail not yet possible with any other body in the solar system beyond Earth, and the LRO data set enables us to tease out subtle but important processes that would otherwise remain hidden," John Keller, LRO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a different statement.
If these lunar faults are still active, shallow "moonquakes" might occur along them. These rumbles should happen most often when Earth's tidal effects are greatest on the moon — when the moon is farthest away from the Earth in its orbit. A network of seismometers on the moon's surface could one day detect these quakes, Watters said.
Watters and his colleaguesdetailed their findings in the October issue of the journal Geology.

The Next Generation of Exploration: The NEOCam Mission

In February of 2014, NASA put out the call for submissions for the thirteenth mission of their Discovery Program. In keeping with the program’s goal of mounting low-cost, highly focused missions to explore the Solar System, the latest program is focused on missions that look beyond Mars to new research goals. On September 30th, 2015, five semifinalists were announced, which included proposals for sending probes back to Venus, to sending orbiters to study asteroids and Near-Earth Objects.

Near-Earth Asteroids (NEO) of large size can potentially orbit close to Earth, making them Potentially Hazardous Objects (PHO). Credit: ESA

Among the proposed NEO missions is the Near Earth Object Camera, or NEOCam. Consisting of a space-based infrared telescope designed to survey the Solar System for potentially hazardous asteroids, the NEOCam would be responsible for discovering and characterizing ten times more near-Earth objects than all NEOs that have discovered to date.
If deployed, NEOCam will begin discovering approximately one million asteroids in the Main Belt and thousands of comets in the course of its 4 year mission. However, the primary scientific goal of NEOCam is to discover and characterize over two-thirds of the asteroids that are larger that 140 meters, since it is possible some of these might pose a threat to Earth someday.

Artist’s concept of the NEOCam spacecraft, a proposed mission for NASA’s Discovery program that would search for potentially hazardous near-Earth asteroids. Credit: NASA/JPL-Caltech

The technical term is Potentially Hazardous Objects (PHO), and it applies to near-Earth asteroids/comets that have an orbit that will allow them to make close approaches to Earth. And measuring more than 140 meters in diameter, they are of sufficient size that they could cause significant regional damage if they struck Earth.
In fact, a study conducted in 2010 through the Imperial College of London and Purdue University found that an asteroid measuring 50-meters across with a density of 2.6 grams per cubic centimeter and a speed of 12.7 kps could generate 2.9 Megatons of airburst energy once it passed through our atmosphere. To put that in perspective, that’s the equivalent of about nine W87 thermonuclear warheads!
By comparison, the meteor that appeared over the small Russian community of Chelyabinsk in 2013 measured only 20 meters across. Nevertheless, the explosive airbust caused by it entering our atmosphere generated only 500 kilotons of energy,  creating a zone of destruction tens of kilometers wide and injuring 1,491 people. One can imagine without much effort how much worse it would have been had the explosion been six times as big!
What’s more, as of August 1st, 2015, NASA has listed a total of 1,605 potentially hazardous asteroids and 85 near-Earth comets. Among these, there are 154 PHAs believed to be larger than one kilometer in diameter. This represents a tenfold increase in discoveries since the end of the 1990s, which is due to several astronomical surveys being performed (as well as improvements in detection methods) over the past two and a half decades.

The NEOCam sensor (right) is the lynchpin for the proposed Near Earth Object Camera, or NEOCam, space mission (left). Credit: NASA/JPL-Caltech

As a result, monitoring and characterizing which of these objects is likely to pose a threat to Earth in the future has been a scientific priority in recent years. It is also why the U.S. Congress passed the “George E. Brown, Jr. Near-Earth Object Survey Act” in 2005. Also known as the “NASA Authorization Act of 2005”, this Act of Congress mandated that NASA identify 90% of all NEOs that could pose a threat to Earth.
If deployed, NEOCam will monitor NEOs from the Earth–Sun L1 Lagrange point, allowing it to look close to the Sun and see objects inside Earth’s orbit. To this, NEOCam will rely on a single scientific instrument: a 50 cm diameter telescope that operates at two heat-sensing infrared wavelengths, to detect the even the dark asteroids that are hardest to find.
By using two heat-sensitive infrared imaging channels, NEOCam can also make accurate measurements of NEO and gain valuable information about their sizes, composition, shapes, rotational states, and orbits. As Dr. Amy Mainzer, the Principal Investigator of the NEOCam mission,  explained:
“Everyone wants to know about asteroids hitting the Earth; NEOCam is designed to tackle this issue. We expect that NEOCam will discover about ten times more asteroids than are currently known, plus millions of asteroids in the main belt between Mars and Jupiter. By conducting a comprehensive asteroid survey, NEOCam will address three needs: planetary defense, understanding the origins and evolution of our solar system, and finding new destinations for future exploration.”

Dr. Mainzer is no stranger to infrared imaging for the sake of space exploration. In addition to being the Principal Investigator on this mission and a member of the Jet Propulsion Laboratory, she is also the Deputy Project Scientist for the Wide-field Infrared Survey Explorer (WISE) and the Principal Investigator for the NEOWISE project to study minor planets.

She has also appeared many times on the History Channel series The Universe, the documentary featurette “Stellar Cartography: On Earth”, and serves as the science consultant and host for the live-action PBS Kids seriesReady Jet Go!, which will be debuting in the winter of 2016. Under her direction, the NEOCam mission will also study the origin and ultimate fate of our solar system’s asteroids, and finding the most suitable NEO targets for future exploration by robots and humans.
Proposals for NEOCam have been submitted a total of three times to the NASA Discovery Program – in 2006, 2010, and 2015, respectively. In 2010, NEOCam was selected to receive technology development funding to design and test new detectors optimized for asteroid and comet detection and discovery. However, the mission was ultimately overruled in favor of the Mars InSight Lander, which is scheduled for launch in 2016.
As one of the semifinalists for Discovery Mission 13, the NEOCam mission has received $3 million for year-long studies to lay out detailed mission plans and reduce risks. In September of 2016, one or two finalist will be selected to receive the program’s budget of $450 million (minus the cost of a launch vehicle and mission operations), and will launch in 2020 at the earliest.
In related news, NASA has confirmed that the asteroid known as 86666 (2000 FL10) will be passing Earth tomorrow. No need to worry, though. At its closest approach, the asteroid will still be at a distance of 892,577 km (554,000 mi) from Earth. Still, every passing rock underlines the need for knowing more about NEOs and where they might be headed one day!
Source: Universe Today, written by Matt Williams

'The Martian' and Reality: How NASA Will Get Astronauts to Mars

by Mike Wall, Space.com Senior Writer   |   October 03, 2015 12:00am ET

NASA wants the world to know that putting boots on Mars is not just a sci-fi dream.
The space agency has been helping promote the new film "The Martian," which hits theaters across the United States today (Oct. 2), as a way to publicize its own plans to send astronauts to the Red Planet in the 2030s.
Setting up a crewed outpost on Mars is NASA's chief long-term goal in the realm of human spaceflight. Indeed, the space agency's operational robotic Mars craft — the Opportunity and Curiosity rovers, and the orbiters Mars Odyssey, Mars Reconnaissance Orbiter (MRO) and MAVEN (Mars Atmosphere and Volatile Evolution) — can be seen as scouts for the human pioneers to come, NASA officials say. [5 Manned Mission to Mars Ideas] 

"The evolution of a Martian starts with our science — starts with our ground-truth that we get from our rovers — and it builds up to human exploration," Jim Green, director of NASA's Planetary Science division, said Thursday (Oct. 1) at Kennedy Space Center in Florida, during an event focusing on "The Martian" and the space agency's Red Planet plans.

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Making it happen

In the film "The Martian" (2015), an astronaut played by Matt Damon has to improvise when his crew leaves him behind by accident. Check out our full infographic to see what we think it would take to survive on Mars.
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NASA is working on a number of different fronts to make a crewed Mars mission happen, Green said.
For example, the agency and its partners are currently conducting an unprecedented yearlong mission aboard the International Space Station (ISS). (Crewmembers generally stay aboard the orbiting lab for 5 to 6 months.)
Researchers are monitoring how NASA astronaut Scott Kelly and cosmonaut Mikhail Kornienko respond physiologically and psychologically to their extended time off Earth, in an effort to help prepare future pioneers for the long journey to Mars and back.
Furthermore, astronauts recently grew lettuce aboard the ISS — and ate it as well — as part of an experiment called "Veggie." The long-term goal of such projects is to make voyaging astronauts less dependent on Earth.
NASA is also developing a crew capsule called Orion and the Space Launch System (SLS) megarocket to help get astronauts to, and from, distant destinations such as Mars. Orion aced its first uncrewed test flight last December, and the SLS is scheduled to make its maiden voyage in 2018.
Technological development is ongoing in other key areas as well. For instance, reseachers are working to improve solar-electric propulsion systems, which use energy from the sun to strip electrons off gas molecules, then send these ions streaming out the back of a spacecraft to generate thrust.
"These are going to be huge ion engines that will allow us to haul tens of tons of material back and forth to Mars," Green said.
Much of this heavy gear — which will consist of human habitat modules and other infrastructure — must make it down to the Martian surface. That's a tall order, since the 1-ton Curiosity rover maxed out NASA's "sky crane" landing system. [How to Land on Mars: Martian Tech Explained (Infographic)]
So NASA is developing new tech, such as inflatable "decelerators" and an enormous supersonic parachute, to help get hefty payloads down safely and softly on the Red Planet. NASA has tested a prototype of this system twice during balloon-aided flights off Hawaii; the decelerator worked perfectly, but the parachute tore both times.

Robotic Red Planet explorers

The science work being done by Red Planet robots feeds into the crewed effort as well. For example, data and images gathered by MRO have allowed researchers to determine that the dark streaks that appear on steep Martian slopes during warm weather are caused by liquid water — a resource that future pioneers might be able to exploit.
"We're developing the science tools now — the continually orbiting and roving on Mars — to be able to get us the information to know what Mars is really like," Green said.
NASA's next Mars rover, which is scheduled to launch in 2020, will continue to build up the knowledge base, while also making concerted strides toward human exploration.
One of the Mars 2020 rover's instruments is a technology demonstration designed to generate oxygen from carbon dioxide in the Red Planet's atmosphere. Another instrument, a ground-penetrating radar, is capable of discovering subsurface aquifers of liquid water, if any exist in the landing zone, Green said.

The path to Mars

NASA is not planning to make the big leap directly from low Earth orbit, where the ISS circles, all the way to Mars. Rather, the agency first aims to test technologies and gain deep-space experience in the "proving ground" of Earth-moon space.
One proving-ground project is the Asteroid Redirect Mission, which involves plucking a boulder off a near-Earth asteroid with a robotic probe and towing the chunk of space rock to lunar orbit for future visitation by astronauts.
NASA plans to accomplish this — the robotic and crewed aspects (which will employ Orion and the SLS) — by 2025.
And the first crewed Mars mission may land not on the Red Planet but on one of its two tiny moons, Phobos and Deimos. Such a strategy would prove out the technologies required to get to Mars orbit, and also dilute the risks and costs of a crewed Red Planet campaign, advocates say.
So some of the steps along the path to Mars still need to be worked out. But the ultimate destination — the Martian surface — is not in doubt, NASA officials say.
"[Putting] boots on Mars is possibly the most exciting thing humans will ever do," NASA chief Charles Bolden said last month during an event at NASA Headquarters in Washington, D.C. that detailed NASA's crewed Mars plans.
"We have been engaged in getting to Mars — getting humans to Mars — for at least 40 years, beginning with the first precursors," he added. "I have no doubt that we can accomplish what we have set our minds to do."

Water on Mars: What Does It Really Mean?

A new find of liquid water fuels hopes that life may yet exist on the red planet.

Traces of salty water have been detected in in gullies and craters on Mars, such as this impact crater                                                                                                                                        

It’s tempting to say that the announcement of liquid water on the surface of Mars heralds a new era in Martian exploration.

You might think that the first human explorers on Mars will park next to a salty stream and use it to manufacture fresh drinking water. Maybe they could even find life in damp Martian nooks and crannies, areas where the dusty red planet can still fuel microbes.

Reality is much more subtle. Finding evidence for flowing water is not the same as finding life. Right now, scientists don’t know where this water is coming from, or if the chemistry in these Martian seeps is even life-friendly. And unfortunately, chances are it will be a long time before we can get there to find out.

“It’s hard to get a spacecraft clean enough to send a lander or rover there right now,” says Bethany Ehlmann, a planetary geologist at Caltech, referring to concerns about hitchhiking Earth microbes contaminating the Martian surface.

But there's still reason for excitement. These seasonal seeps, which scientists call recurring slope lineae, “are probably the best place to look for modern life,” she says.

Odds of Life

Here's what scientists know. Analyses have confirmed that enigmatic streaks that appear in summertime on the planet's slopes are produced by liquid water—salty water, perhaps capable of sustaining chemical reactions and even life. 

Like Mars itself, the dark watery streaks are ruggedly beautiful, as seen in photographs taken by the HiRISE camera aboard the Mars Reconnaissance Orbiter. But for all their picturesque drama, these dark marks represent more of a trickle than a flow.

It’s possible they’re fed by some kind of underground aquifer, or a buried icefield that thaws in warmer weather and sends melted Mars water sliding downhill.

While not outside the realm of possibility—we do know there’s ice buried beneath the Martian surface—such scenarios aren’t as likely as the one scientists favor: The water comes from the atmosphere. If that's true, it’ll be a much tougher resource to tap into.

But how could water from the atmosphere form these dark streaks? On Mars, as on Earth, salts on the surface can absorb atmospheric water vapor and trap it in their crystal structures. Then, when the soggy crystals warm up, they dissolve. The whole liquidy mix surrenders to the tug of gravity, and off it goes, tumbling downhill.

In Chile’s super-dry Atacama desert, this exact type of system—called deliquescence—is the key to supporting some rather extreme life, says NASA astrobiologist Chris McKay.

But there’s no guarantee this is happening on Mars. McKay notes that the type of salts near the Martian streaks, called perchlorates, form different watery mixtures than the salts we’re most used to on Earth. In fact, it’s possible the perchlorate streaks could behave similarly to Antarctica’s Don Juan Pond, which is the saltiest liquid water body on Earth—and totally dead.

“Such a brine is not suitable for life and is of no interest biologically,” McKay says. “Nothing can live in the brine of Don Juan Pond.”

Follow the Water

So, seeps fueled by atmospheric humidity might not make the most convenient water well for human colonists, and they might not even be ideal habitats for Martian microbes—but wouldn’t it be worth finding out?

Of course. What we know so far, based on the single example of Earth, is that life tends to show up wherever there’s water. That’s why NASA’s search for life beyond Earth has been driven by the mantra, “Follow the water.”

The frustrating irony here is that NASA can’t follow this particular water. Not yet.

Mars Once Held an Ocean An ancient sea once covered a fifth of the planet’s surface, astronomers found by calculating how much water the planet has lost over time.

Sending a spacecraft to an area where liquid water flows is much too risky, cautions NASA’s Office of Planetary Protection. Finding water in the streaks will brand them as a "special region," an area where spacecraft can land only after thorough cleaning or sterilization, says Ernst Hauber of the German Aerospace Center.

If hitchhiking microbes were to somehow survive the journey to Mars and find themselves in a briny bath, it’s possible they could gain a foothold and contaminate the red planet. Such a scenario would not only complicate any future detection of life on Mars, but also introduce a potential disaster: Think about how great we are at hastening the spread of invasive species on Earth.

It’s certainly worth the caution, though humans walking on Mars (which some say is the next goal in solar system exploration) are much more likely to shed microbes than a sterilized robot is, and Earth microbes aren't necessarily likely to thrive in Mars brines.

If there’s one big story from the past decade of planetary exploration, it’s that water is everywhere. It’s tucked into moon dust, frozen in Mercury’s shadowed craters, streaming off the backs of comets, and sequestered inside the shells of icy moons. Mars, finally, has joined the population of bodies where we know water flows—and that’s interesting enough on its own, without the breathless speculation.

“Modern Mars is right ‘on the edge,' ” Ehlmann says, as an active world where liquid water exists even today. “Just a slight tweak in climate could make waters even more widespread.”

 

Perplexing Pluto: New ‘Snakeskin’ Image and More from New Horizons

The newest high-resolution images of Pluto from NASA’s New Horizons are both dazzling and mystifying, revealing a multitude of previously unseen topographic and compositional details. The image below — showing an area near the line that separates day from night — captures a vast rippling landscape of strange, aligned linear ridges that has astonished New Horizons team members.
“It’s a unique and perplexing landscape stretching over hundreds of miles,” said William McKinnon, New Horizons Geology, Geophysics and Imaging (GGI) team deputy lead from Washington University in St. Louis. “It looks more like tree bark or dragon scales than geology. This’ll really take time to figure out; maybe it’s some combination of internal tectonic forces and ice sublimation driven by Pluto’s faint sunlight.”
The “snakeskin” image of Pluto’s surface is just one tantalizing piece of data New Horizons sent back in recent days. The spacecraft also captured the highest-resolution color view yet of Pluto, as well as detailed spectral maps and other high-resolution images.

In this extended color image of Pluto taken by NASA’s New Horizons spacecraft, rounded and bizarrely textured mountains, informally named the Tartarus Dorsa, rise up along Pluto’s day-night terminator and show intricate but puzzling patterns of blue-gray ridges and reddish material in between. This view, roughly 330 miles (530 kilometers) across, combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC) on July 14, 2015, and resolves details and colors on scales as small as 0.8 miles (1.3 kilometers). Credits: NASA/JHUAPL/SWRI

The new “extended color” view of Pluto – taken by New Horizons’ wide-angle Ralph/Multispectral Visual Imaging Camera (MVIC) on July 14 and downlinked to Earth on Sept. 19 – shows the extraordinarily rich color palette of Pluto.
“We used MVIC’s infrared channel to extend our spectral view of Pluto,” said John Spencer, a GGI deputy lead from Southwest Research Institute (SwRI) in Boulder, Colorado. “Pluto’s surface colors were enhanced in this view to reveal subtle details in a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a wonderfully complex geological and climatological story that we have only just begun to decode.”

This cylindrical projection map of Pluto, in enhanced, extended color, is the most detailed color map of Pluto ever made. It uses recently returned color imagery from the New Horizons Ralph camera, which is draped onto a base map of images from the NASA’s spacecraft’s Long Range Reconnaissance Imager (LORRI). The map can be zoomed in to reveal exquisite detail with high scientific value. Color variations have been enhanced to bring out subtle differences. Colors used in this map are the blue, red, and near-infrared filter channels of the Ralph instrument. Credits: NASA/JHUAPL/SWRI

Additionally, a high-resolution swath across Pluto taken by New Horizons’ narrow-angle Long Range Reconnaissance Imager (LORRI) on July 14, and downlinked on Sept. 20, homes in on details of Pluto’s geology. These images — the highest-resolution yet available of Pluto — reveal features that resemble dunes, the older shoreline of a shrinking glacial ice lake, and fractured, angular water ice mountains with sheer cliffs. Color details have been added using MVIC’s global map shown above.

High-resolution images of Pluto taken by NASA’s New Horizons spacecraft just before closest approach on July 14, 2015, reveal features as small as 270 yards (250 meters) across, from craters to faulted mountain blocks, to the textured surface of the vast basin informally called Sputnik Planum. Enhanced color has been added from the global color image. This image is about 330 miles (530 kilometers) across. For optimal viewing, zoom in on the image on a larger screen. Credits: NASA/JHUAPL/SWRI

This closer look at the smooth, bright surface of the informally named Sputnik Planum shows that it is actually pockmarked by dense patterns of pits, low ridges and scalloped terrain. Dunes of bright volatile ice particles are a possible explanation, mission scientists say, but the ices of Sputnik may be especially susceptible to sublimation and formation of such corrugated ground.

High-resolution images of Pluto taken by NASA’s New Horizons spacecraft just before closest approach on July 14, 2015, are the sharpest images to date of Pluto’s varied terrain—revealing details down to scales of 270 meters. In this 75-mile (120-kilometer) section of the taken from the larger, high-resolution mosaic above, the textured surface of the plain surrounds two isolated ice mountains. Credits: NASA/JHUAPL/SWRI

Beyond the new images, new compositional information comes from a just-obtained map of methane ice across part of Pluto’s surface that reveals striking contrasts: Sputnik Planum has abundant methane, while the region informally named Cthulhu Regio shows none, aside from a few isolated ridges and crater rims. Mountains along the west flank of Sputnik lack methane as well.
The distribution of methane across the surface is anything but simple, with higher concentrations on bright plains and crater rims, but usually none in the centers of craters or darker regions.  Outside of Sputnik Planum, methane ice appears to favor brighter areas, but scientists aren’t sure if that’s because methane is more likely to condense there or that its condensation brightens those regions.

The Ralph/LEISA infrared spectrometer on NASA’s New Horizons spacecraft mapped compositions across Pluto’s surface as it flew by on July 14. On the left, a map of methane ice abundance shows striking regional differences, with stronger methane absorption indicated by the brighter purple colors here, and lower abundances shown in black. Data have only been received so far for the left half of Pluto’s disk. At right, the methane map is merged with higher-resolution images from the spacecraft’s Long Range Reconnaissance Imager (LORRI). Credits: NASA/JHUAPL/SWRI

“It’s like the classic chicken-or-egg problem,” said Will Grundy, New Horizons surface composition team lead from Lowell Observatory in Flagstaff, Arizona. “We’re unsure why this is so, but the cool thing is that New Horizons has the ability to make exquisite compositional maps across the surface of Pluto, and that’ll be crucial to resolving how enigmatic Pluto works.”
“With these just-downlinked images and maps, we’ve turned a new page in the study of Pluto beginning to reveal the planet at high resolution in both color and composition,” added New Horizons Principal Investigator Alan Stern, of SwRI. “I wish Pluto’s discoverer Clyde Tombaugh had lived to see this day.”
Source: NASA

Radio Telescopes Could Spot Stars Hidden in the Galactic Centre

The centre of our Milky Way galaxy is a mysterious place. Not only is it thousands of light-years away, it’s also cloaked in so much dust that most stars within are rendered invisible. Harvard researchers are proposing a new way to clear the fog and spot stars hiding there. They suggest looking for radio waves coming from supersonic stars. The team will publish its results in a paper in Monthly Notices of the Royal Astronomical Society.
“There’s a lot we don’t know about the galactic centre, and a lot we want to learn,” says lead author Idan Ginsburg of the Harvard-Smithsonian Center for Astrophysics (CfA). “Using this technique, we think we can find stars that no one has seen before.”

The centre of the Milky Way. Image made with ISAAC, the Very Large Telescope (VLT) near- and mid-infrared spectrometer and camera. Credit: ESO/R. Schoedel. CC-BY, click for full image

The long path from the centre of our galaxy to Earth is so choked with dust that out of every trillion photons of visible light coming our way, only one will reach our telescopes. Radio waves, from a different part of the electromagnetic spectrum, have lower energies and longer wavelengths. They can pass through the dust unimpeded.
On their own, stars aren’t bright enough in the radio for us to detect them at such distances. However, if a star is traveling through gas faster than the speed of sound, the situation changes. Material blowing off of the star as a stellar wind can plough into the interstellar gases and create a shock wave. And through a process called synchrotron radiation, electrons accelerated by that shock wave produce radio emission that we could potentially detect.
“In a sense, we’re looking for the cosmic equivalent of a sonic boom from an airplane,” explains Ginsburg.
To create a shock wave, the star would have to be moving at a speed of thousands of kilometres per second. This is possible in the galactic centre since the stars there are influenced by the strong gravity of a supermassive black hole. When an orbiting star reaches its closest approach to the black hole, it can easily acquire the required speed.
The researchers suggest looking for this effect from one already known star called S2. This star, which is hot and bright enough to be seen in the infrared despite all the dust, will make its closest approach to the Galactic centre in late 2017 or early 2018. When it does, radio astronomers can target it to look for radio emission from its shock wave.
“S2 will be our litmus test. If it’s seen in the radio, then potentially we can use this method to find smaller and fainter stars – stars that can’t be seen any other way,” says co-author Avi Loeb, also of the CfA.
Source: RAS