2014년 5월 26일 월요일

My Time With Comet Lovejoy (Op-Ed)

On September 7, 2013, Australian Terry Lovejoy — using an 8-inch Schmidt-Cassegrain telescope — discovered what would be designated comet Lovejoy. 

During October, the comet moved into the Northern hemisphere at a time of great excitement for comets in general, as the stargazing community waited for "The Comet of the Century": the sun-grazing comet, ISON . My own early attempts at seeing comet ISON were disappointing at best. Weather and ISON's dimness left me frustrated and I decided to seek better, brighter game.

That period reminded me of a time long ago when the world waited for the arrival of mighty comet Hale-Bopp C/1995 O1. Many of us looked forward to Hale-Bopp's entrance onto the cosmic stage with great anticipation, when suddenly, nearly a year before its arrival, it was upstaged from out of nowhere by the majestic comet, Hyakutake. Comet Hyakutake taught me just how little we humans knew about the universe around us. I remember those days, sketching a star chart showing where to look for comet Hyakutake , then throwing it on the ground as I stepped out of my pickup truck at my dark sky site in Algoma, Wisc. I stood there staring at the amazing specter of Hyakutake's tail stretching across the entire darkening sky. It was then that I asked myself, "How did we not see this coming?" Our science is great, but people should be humbled that we did not see this one coming — be wary of pride.

First attempt, November 13, 2013

To me, comet Lovejoy seemed Heaven sent. Brightening rapidly and well placed for photography in November last year, it swiftly captured my attention. November 13, 2013, promised clear but cold skies near my home in Jadwin, Mo., when I would make my first attempt to see and photograph Lovejoy. The weather, thus far, had been typical November: cloudy, rainy and cold. But that night held promise. I remember feeling glad that I had an opportunity like this, a near naked-eye comet and clearing skies. It would be an early morning comet, but that was a small sacrifice after years waiting for conditions like those. I was using an f9, 5-inch apochromatic refractor on which I had just replaced the focuser. This would be the test image for my newly modified telescope.

As the night wore on, I scanned the skies with binoculars until the moment I made first contact with comet Lovejoy. Slewing my telescope (moving to aim at a point in the sky), I found the comet in a 2-inch-wide-angle eyepiece, one that gave me low power but a bright field of view. The eyepiece was a gift my mom had given me for my birthday the Christmas before (yes, I am indeed a Christmas baby).

There I stood at the eyepiece, shivering not with cold but excitement. Behold a marvel in the darkness! "Calm down," I told myself aloud, "you have work to do." I then slipped the diagonal — a device that that makes it easier to use refracting telescopes when the eyepiece end of the telescope is uncomfortably low to the ground — and eyepiece out of the telescope's focuser, just then realizing how well the new focuser worked, and replaced it with a digital single-lens reflex (DSLR) camera, refocusing carefully on the faint glowing orb that was Lovejoy. Selecting ISO speeds and exposure lengths, gradually improving the image gave me great pleasure standing alone in the cold of my front yard. The sky here is very dark and is the reason I live in the backwoods of Jadwin. After a while, I knew I had captured my best image of the night.

Second attempt, November 28, 2013

The passing of truly great comets is an extremely rare thing. It is my advice to the budding astrophotographer to never miss an opportunity to spend as much time as possible with these strange visitors from the distant Oort cloud. Do not take them for granted, they are ever-changing and hold surprises for us Earthly observers.

Third attempt, November 30, 2013

Due to poor weather conditions, nearly two weeks had elapsed between my first and second attempt at documenting comet Lovejoy's passing. Only two days after my last outing with the beautiful comet, I had another chance. I had learned a lot from my previous outings, and liked what I had done so far. Now it was time for something different: I would image in color.

I have always loved black and white photography. In my opinion, it gives the most honest rendition of a subject and no false-color issues — just a collection of grey tones and a sort of purity not found in other forms of photography. But comet Lovejoy displayed a beautiful color, a greenish glow that could not be ignored. I favor refractors, and the wind can cause them to jiggle and vibrate and cause them problems in general, more so than telescopes of other designs. That night was windy, and I tried to make my exposures that morning between the wind gusts. I would listen to the rustling of the pine trees: they would warn me when the wind would start to pick up and I would then end my exposure. Who needs a wind gauge when you have a pine tree?

My last hours with comet Lovejoy, December 12, 2013

The comet's final days were in December. Poor weather had kept me indoors, with the exception of chores around the farm. It was very cold, as nighttime temperatures hovered around and below zero degrees. I had been reading online about the comet and viewing pictures, and noticed a recurring theme in comments made by amateur astronomers. Observers stated that they had seen a strange "sparking" in and around the comet's tail. This idea intrigued me: Might I capture this phenomenon in a photograph? 

If I braved the cold, as I had done so many nights before, perhaps it could be done in a wide-angle photograph — worth a try if I had some clear skies. Clear and cold was the forecast for that night, and I planned to set up a home-built camera tracker as near the house as I could. I would make exposures with a 35mm Carl Zeiss manual focus lens, ducking inside regularly to warm up for a couple of minutes before setting out again. The comet was rather low in the east before dawn, and I realized I would have to make good use of my time if I was to capture the "sparking" phenomenon in Lovejoy's tail. As time dragged on and the bitter cold tried its best to discourage me, in my last exposure I seemed to capture one of those reported sparks. It was Geminid meteor season, and the spark might have been just that, but I have found from personal experience that meteor activity is often high when a comet is in the sky. And this small spark of a meteor was apparently close to comet Lovejoy's tail. A few hours later, I fell sound asleep dreaming that perhaps I had done what I had set out to do. I might never know for sure, but in my heart I thought maybe so. I like to think I did!

The weather after that winter's night deteriorated rapidly into clouds and snow and those were to be my final hours spent with this beautiful comet. After a time one forgets the early mornings and the cold temperatures, but what does live on are the memories of the shimmering stars and the graceful comet with the beautiful name playing with meteors before the sunrise.

Source of Article: Space.com
By Victor Rogus, Amateur Astronomer

Want to Find Alien Life? It Will Take A Lot of Luck

Humanity will have the tools to detect alien life in the next two decades, but whether scientists can actually find life in another solar system depends a lot on luck, a panel of experts said Wednesday (May 21).

While the James Webb Space Telescope, expected to launch in 2018, will have the ability to search for the chemical signatures of life in the atmospheres of alien worlds, it doesn't necessarily guarantee that scientists will find extraterrestrial life somewhere in the universe. No one is sure how life begins or how ubiquitous it is, making it very difficult to pinpoint when and where to find it, scientists said during a session here at the National Space Symposium.

"We don't know how many planets we're going to have to examine before we find life, and not finding it on 10 or 100 doesn't mean it's not there," John Grunsfeld, NASA's associate administrator for the science mission directorate said during the panel. "This may be very tricky."

Scientists can stack the odds in their favor, however. Building new, bigger space telescopes could help researchers look at more stars, making the odds better that exoplanet hunters will find signs of life — like plant-produced oxygen or potentially methane — within an atmosphere.

"We can't really tell what life is," MIT astrophysicist and exoplanet hunter Sara Seager said. "All we can do is work with what life does. Life metabolizes and generates gasses, so that's what we're looking for … The good news is, whatever life is, as long as it uses chemistry, we're all set."

A mission still in the early stages of development could also help scientists investigate alien worlds even without the use of a large telescope. Called a "starshade," the huge sunflower-shaped craft would block light from a star to allow a well-positioned space telescope to look at the atmospheres of rocky planets orbiting sun-like stars, a historically difficult feat.
By using the starshade, scientists can hunt for an "Earth twin" orbiting a yellow star in the habitable zone like Earth, the only planet scientists know hosts life.

"We'll have the capability to find it [life] and we'll have that capability within a decade with James Webb and hopefully within two decades with an Earth twin, but beyond that, it's really just up to chance," Seager, who is affiliated with the starshade group, said.

Life could also be lurking in our solar system, and scientists wouldn't necessarily need a huge telescope to figure that out. NASA has started investigating a possible mission to Jupiter's icy moon Europa to be launched sometime in the 2020s. Scientists think it's possible that microbial life could survive in the ocean beneath the moon's ice shell.
Finding life under Europa's icy shell could also impact the hunt for living things outside of the solar system.

"I think it's fair to say that we just want to see one example," Seager said. "If we see one, we almost know that it's everywhere because we need to be reassured, we need confidence that life is actually ubiquitous."

Source of Article: Space.com
By: Miriam Kramer, Staff Writer 

2014년 4월 12일 토요일

NASA Mulls Unplanned Spacewalk to Fix Space Station Computer Outage

A backup computer outage on the International Space Station is forcing NASA to discuss plans for a possible spacewalk repair by astronauts in orbit, a move that could delay the planned Monday launch of a commercial SpaceX cargo ship to the orbiting lab.

NASA officials decided Saturday (April 12) to avoid a final decision on whether to delay the unmanned SpaceX Dragon launch as station engineers weigh options to fix the backup computer, which stopped responding to commands Friday and is part of the station's robotics system. SpaceX currently aims to launch the Dragon capsule from Florida's Cape Canaveral Air Force Station at 4:58 p.m. EDT (2058 GMT) on Monday. Station astronauts plan to capture the craft with a robotic arm on Wednesday.

"Station program officials, flight controllers and teams of engineers are working to determine whether there is any risk to launching the SpaceX cargo craft Monday," read a NASA statement released Saturday. The main issue is whether the space station's robotics system has enough redundancy without the backup computer.

Because the station's robotic arm is vital to capturing the Dragon spacecraft and attaching it to the space station, NASA is studying the issue extremely closely. The space agency rescheduled two Sunday morning press conferences on the upcoming SpaceX mission to later Sunday afternoon while engineers discuss their options.

Astronauts on the space station would have to perform a spacewalk to fix or replace the computer. The MDM computer repair is one of 12 scenarios NASA astronauts regularly train for before flying to the space station.

The problem cropped up late Friday, when a backup computer known as a Multiplexer-Demultiplexer, or MDM for short, stopped responding to commands. The device is located on the station's exterior and serves as a backup controller for the Mobile Transporter, a railcar that moves the Canadarm2 robotic arm along the space station's backbone-like main truss.

The primary computer that controls the station's Mobile Transporter is working perfectly, NASA officials wrote in the status update. But the backup computer, called EXT-2, failed a routine health check on Friday.

The failed MDM backup computer is one of more than a dozen on the station's exterior "that route computer commands to various systems on the outpost," according to the NASA statement.

SpaceX's current Dragon mission to the space station has been delayed since March due to an unrelated damage to ground radar equipment used during launches from the Cape Canaveral Air Force Station. This mission, called Commercial Resupply Services 3, is SpaceX's third resupply mission for NASA since 2012 under a $1.6 billion contract.
If SpaceX does not launch its Dragon mission on Monday, the mission could potentially target a backup launch day of Friday, April 18. But that will depend on any NASA plans for a spacewalk repair.

SpaceX plans to fly at least 12 Dragon cargo missions to the space station for NASA under its contract. Another company, the Dulles, Va.-based Orbital Sciences Corp., has a $1.9 billion deal with NASA to provide eight resupply flights using its own Antares rockets and unmanned Cygnus spacecraft.

Source of Article: Space.com
By Tariq Malik, Managing Editor

Capturing the 2000 Lunar Eclipse from 'Hell on Ice'

ictor Rogus is an amateur astronomer, and this is the third in his series of exclusive Space.com posts about amateur astronomy. He contributed this article to Space.com's Expert Voices: Op-Ed & Insights.

It was Jan. 20, 2000, and the first winter storm of a seemingly mild season had struck the American Midwest. It deposited about six inches of snow, enough to cover the gray landscape in a blanket of crisp white. But the storm brought with it a burst of polar air that would send the air temperatures in northeast Wisconsin into the -10 to -15-degrees-below-zero levels. With a brisk wind chill off of Lake Michigan that would drop the mercury into the -34 degree zone, these are the conditions I would have to endure in my attempt to capture the totally eclipsed Moon with a "starry background" on film.

It was a Thursday and I was needed at work, but with a fresh batch of vacation days under my belt, my intention was to set out to my dark-sky site in Algoma, Wisc., photograph the eclipse, and then take Friday off as a vacation hiliday. My Jeep Wrangler was loaded with everything I needed to create a multiple-piece composite image of the moon's complete umbral display, as well as the moment of totality. I would also attempt a wide-angle piggyback shot of the eclipsed moon against its heavenly background of winter stars. This would be my first astro photo outing of the New Year and the new millennium; I hoped for a memorable night and a fine photograph or two.

It was going to be a cold night, but the sky was predicted to be crystal clear, and this event would be visible over most of the United States. Many fine photographers would try to capture it. With the cold spell many were experiencing, many would be tempted to set up telescopes in the backyard and run out at the critical moment just before totality and snap off a roll of film. Because it was a work night, many more would not try at all, even if their skies were clear, I thought. In the last few days, I had been trying to conceive of a plan for creating a photographic image that is somehow different from the rest — this gives one a definite advantage in the strength of their portfolio. This is why I chose to drive 200 miles of slippery roads to the dark skies of Algoma. This is why I chose to endure the inhuman cold and biting wind of that icy great Lake's shore.

Although I managed to leave work an hour early, I did not arrive at my destination until after dark. Guiding the Jeep through the snowdrifts, I found the place where I would make my stand. The drive had taken over five hours, and I was tired already. Partly cloudy skies greeted me as I exited my vehicle. Instantly the cold, night air bit the exposed skin on my face and hands, and for the first time I felt a sting of doubt.
Back in the Jeep I called my wife to let her know I had arrived safely. "I'm not sure I can even do this," I said. "It's so cold and there are clouds here!"
"Oh no!" She replied. "Come home, it's clear here."
But there was just no way, as the umbral phase of the eclipse would begin at 9:01 p.m., and there was just no time for a change of plans. I made my bed, now it was time to sleep in it — for better or worse.

Wisconsin Weather Radio was predicting clear (and dangerously cold) skies, except for extreme-northwest Wisconsin along Lake Superior where partly cloudy skies would prevail. The bright, full moon played hide and seek behind the fast-moving, but clearing, clouds while I made plans to work in five-minute shifts to unload my Jeep and set up my equipment. At this point, it was ten degrees below zero and the temperature was still dropping. First, I changed into my cold weather clothes, then steadily working while warming myself in the Jeep, I began to make progress. My telescope was assembled and my gear was organized. It was about 7:00 o'clock, I would relax for an hour, and then polar align the telescope's mount at 8:00 o'clock.

The moon was climbing higher, and I could no longer see it through my windshield. My wristwatch hung over the rear view mirror, ready to time segments between exposures and I felt as ready as I could be. With a little time to kill, I placed a call to my teacher, and friend, Mark, who at the time was teaching an art class. Leaving a message on his answering machine, I told him what he was missing and how cold it was. "It's like Hell on ice," I said.

At 9:00 o'clock, I begin to make my first battery of exposures — it was nearly impossible to touch the metal parts of the telescope with bare hands. Because of the strong wind gusts off the lake, I had set my tripod low to the ground and already knew that I would be crawling on the snow just to focus through the camera's back. At that point, the eclipse had begun, and I continued making exposures every ten minutes, right on schedule. The dark shadow of the Earth swiftly shrouded crater after crater. Totality was predicted to be at 10:44 p.m. CST and I felt comfortable and confident as I proceed toward that milestone.

The Jeep continually idled with the heater on "high" as I attended to the business of bracketing photographs through my five-inch refractor at ten-minute intervals. Then, without warning, with about ten minutes before lunar totality, the camera at the prime focus setting of the telescope refused to work. It was frozen and the shutter would not operate.
Thinking it must be broken I removed the camera from the wide-angle "piggyback" station and reassigned it to prime-focus duty — there would be no wide angle shot, the camera was needed on the main optical tube. It worked well there for the next set of photographs, and then it too failed to function, frozen solid. With my two frozen cameras in hand, I re-entered the warm Jeep to recompose myself and try to get at least one camera working again. My fingers were numb as I manipulated the camera bodies in an attempt to warm them enough to finish the job.

Suddenly, one of them sprung to life, and I was instantly out the door, reattaching it to the telescope focuser. Looking up to gauge the progress of the eclipsing moon, I saw a very bright, beautiful meteor trail seem to pass right below the reddening lunar face. Soon the sky became quite dark, with the exception of millions of stars filtering into view with very little moonlight to overpower their presence.

When I had first arrived here, even though the Sun had set, the bright moon light on the snow made it easy for me to see what I was doing. But now, with the Moon was nearly fully eclipsed, and it was nearly as dark as a moonless night.

At the time it was hard to believe, but as I next reached for the prime-focus camera body, it dropped right out of the telescope's focuser into my hand. The small screws in the T-ring adapter had loosened and the adapter had just fallen apart. Back in the Jeep, a pocketknife served as a screwdriver to repair the unit with about two minutes remaining before totality. By now, I was low on film and decided to reload the camera for the moment of totality. As I carefully rewound the exposed film inside, the camera at times I could feel it tearing and cracking. It was so cold that the film was actually beginning to freeze and crack inside the cameras.

The leaders on the film rolls would actually snap off as they went from being tightly wound around the take-up spool to a flattened position. Despite this difficulty, no images were lost — and the film only sustained minimal damage.
The cold night dragged on, and the moon steadily brightened the landscape as it slipped from behind the Earth's shadow. When the event was over and the Moon was again full, I hurried back into my Jeep, where I remained warming myself for about twenty minutes. Then, deciding that there was no more reason for me to stay, I began working again in five-minute shifts, disassembling my equipment and repackaging it for the long ride home.
Ultimately I realized that I had gathered enough images to create a composite photograph that would tell the entire story of the first total lunar eclipse over North America in the new century.

Source of Article: Space.com
By: Victor Rogus, Amateur Astronomer

2014년 3월 25일 화요일

Incredible Technology: Giant Starshade Could Help Find an Alien Earth

A flower-shaped spacecraft may help scientists see Earth-like alien worlds like never before.

Called a "starshade," the huge, sunflower-like spacecraft would deploy to its full size in space, blocking the light of distant stars so that a space-based telescope can image exoplanets in orbit around the stars. With this technology, researchers could directly image other worlds and potentially find long sought-after Earth twins, a historically difficult task for alien planet hunters.

While still in the early phases of development, the starshade could hunt for small planets around bright, nearby stars. This would help scientists learn more about the planets and even hunt for signs of potential life by peering into the alien worlds' atmospheres. 

"It's a very specialized screen in space," planetary scientist and MIT astrophysicist Sara Seager said of the starshade concept. "It blocks out the light from the star. Only the planet's light enters the telescope. This is not what we traditionally do. Traditionally, the telescope does everything. … It's the only way to find Earths with a relatively small and simple space telescope."

A small telescope in space

As it stands now, the assumed $1 billion mission would be able to target about 55 bright stars in a three-year span. Seager, the chair of NASA's science and technology definition team for the starshade project, thinks it's possible to find Earth-like planets orbiting 22 of those 55 stars targeted by the mission.

One major advantage to the starshade is that astronomers won't need to couple it with a large, extremely expensive space telescope. By blocking out the light of a star before that light ever reaches the telescope, the starshade eliminates the need for a huge telescope, Seager said.

"You don't need a very fancy telescope that's highly thermally and mechanically stable," Seager told Space.com. "You can use any old space telescope. We can buy a telescope. That's what we're thinking of. … It sounds a little funny, but any telescope will do."

Engineering a starshade

Building a starshade poses a serious engineering challenge. While the telescope and starshade can launch together, the starshade will need to move out from the telescope once both robots reach space.

"[Most starshade designs] are tens of meters [in diameter] and flying tens of thousands of kilometers from the telescope," Seager said. "It's challenging. It sounds insane. The thing is, no matter how you do it, it's really difficult."

But it's also still very difficult to create a large telescope with the internal machinery used to correct for starlight, Seager added.

The starshade itself needs to be designed with extreme accuracy so that it can block light effectively once in space. Researchers on the ground at Princeton University in New Jersey and NASA's Jet Propulsion Laboratory in California are working to test models of the starshade now.

"Our current task is figuring out how to unfurl the starshade in space so that all the petals end up in the right place, with millimeter accuracy," Princeton professor Jeremy Kasdin, the principal investigator of the starshade project, said in a statement.

Space sunflower

Once in space, the starshade unfolds and is positioned between the star and the telescope. The shade's unique shape blocks the starlight, potentially revealing exoplanets in orbit around the star that couldn't have been seen previously. With the light blocked, a telescope can directly image the planets.

"The shape of the petals, when seen from far away, creates a softer edge that causes less bending of light waves," Stuart Shaklan, lead engineer on the starshade project at JPL, said in a statement. "Less light-bending means that the starshade shadow is very dark, so the telescope can take images of the planets without being overwhelmed by starlight."

The starshade would come equipped with thrusters to maneuver into different positions to block the light of the 55 stars it will blot out through the course of the mission. Although it will take time to move the starshade into place for each target, the telescope can perform other astrophysics tasks while waiting for the next star to come into view, Seager said.

Finding Earth's twin

NASA's Kepler mission hunted for exoplanets until it suffered a critical failure last year. Unlike a starshade, Kepler used the transit method, recording small dips in a star's light as a planet passed in front of it, to find other worlds.

The Transiting Exoplanet Survey Satellite (TESS), scheduled for launch in 2017, also uses the transit method to find exoplanets, and this mission is expected to target other stars in a wider swath of sky. TESS probably won't find Earth twins, but it will be able to see rocky planets around stars that are smaller than the sun, Seager said.
With the starshade mission, scientists could potentially find Earth-twins orbiting sun-like stars.

"These Kepler planets are too far away for us to directly study atmospheres of small planets," Seager said. "We mostly decided now that transits won't work for true Earth analogues. For Earth and sun-like stars, you just have to think of the size of the atmosphere — it's like a ring compared to the sun. It's tiny. We don't think we can do [image] that, not to mention that transits are rare. One in 200 Earths will transit, so finding one around a bright enough star may never happen. … Direct imaging is inevitable."

Source of Article: Space.com
By Miriam Kramer, Staff Writer

Mars Rover Curiosity Takes Aim at Next Martian Science Target

After a long stretch of pedal-to-the-metal driving, NASA's Mars rover Curiosity has its next science target in sight.
The 1-ton Curiosity rover is just 282 feet (86 meters) north of a site called "the Kimberley," where four different types of terrain intersect. The rover's handlers are keen to study the Kimberley rocks and may even break out Curiosity's sample-collecting drill at the site, NASA officials said.
"The orbital images didn't tell us what those rocks are, but now that Curiosity is getting closer, we're seeing a preview," Curiosity deputy project scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said in a statement.

"The contrasting textures and durabilities of sandstones in this area are fascinating," Vasavada added. "While superficially similar, the rocks likely formed and evolved quite differently from each other."

The Kimberley sandstones represent a different type of rock for Curiosity to examine. Since touching down inside Mars' huge Gale Crater in August 2012, the rover has primarily scrutinized finer-grained mudstones, researchers said.
Some of those mudstones, at a site called Yellowknife Bay, preserved evidence of an ancient stream-and-lake system, leading mission scientists to announce last year that Mars could have supported microbial life billions of years ago.

Understanding variations in Martian sandstones — such as why some are harder than others — could help scientists piece together parts of the Red Planet's past and explain the large-scale contours of Gale Crater, researchers said.

"A major issue for us now is to understand why some rocks resist erosion more than other rocks, epecially when they are so close to each other and are both likely to be sandstones," said Michael Malin, of Malin Space Science Systems in San Diego. Malin is the principal investigator for Curiosity's Mast Camera and Mars Descent Camera.

Curiosity is currently en route to the base of Mount Sharp, which rises 3.4 miles (5.5 kilometers) into the sky from Gale Crater's center. The rover's handlers want Curiosity to climb up Mount Sharp's foothills, reading a history of Mars' changing environmental conditions as it goes.

Curiosity left the Yellowknife Bay area last July. While the six-wheeled robot has stopped occasionally since then to examine rocks, the mission team has mainly prioritized making tracks. The road to Mount Sharp covers more than 5 miles (8 km); Curiosity should get there around the middle of this year, officials have said.

The long journey has been hard on Curiosity's metal wheels, spurring the rover team devise ways to minimize wear and tear. Their strategies — which include driving Curiosity backward for stretches and choosing a less punishing route — appear to be paying off, with the wheel-puncture rate dropping to just 10 percent of what it was a few months ago.

"The wheel damage rate appears to have leveled off, thanks to a combination of route selection and careful driving," said JPL's Richard Rainen, mechanical engineering team leader for Curiosity. "We're optimistic that we're doing OK now, though we know there will be challenging terrain to cross in the future."

Source of Article: Space.com
By Mike Wall, Senior Writer 

It's Time to Extend Routine Space Operations to the Moon (Op-Ed)

When the XPRIZE Foundation announced the Google Lunar XPRIZE in 2007, Astrobotic Technology chairman Red Whittaker declared his intention to compete on the first day. Since then, we have worked methodically on the technology and operations for the $20 million Grand Prize. We have approached this from the outset as an opportunity to build a business.
With only a few lunar landings since Apollo, there remains a deep cultural belief that they are extraordinarily difficult and expensive. Bold, risky pursuits are called "moon shots." Indeed, NASA estimated that the Apollo program cost $170 billion in 2005 dollars — about $28 billion for each of the six landings.

In the 42 years since Apollo, space technology has matured. Most subsystems needed for lunar landing — from star trackers (cameras that measure a spacecraft's attitude relative to the stars) to propulsion — are commercially available off-the-shelf. Launches are commercially available to geosynchronous transfer orbit or trans-lunar injection. The total cost for a lunar landing that uses a launch vehicle's full capacity (versus flying a smaller mission as secondary payload) is now between $100 million and $200 million. For comparison, DirecTV's satellite fleet includes a dozen satellites that cost an estimated $700 million each.

Although the technology is now in reach, bootstrapping a new market is always challenging. Businesses and research institutions won't routinely develop lunar payloads until regular, affordable transport is assured, but the transport business won't mature until reliable payload customers justify the investment.

The Google Lunar XPRIZE — the largest international incentive prize of all time — has been essential to breaking that deadlock. In addition to the $20 million Grand Prize, the original $30 million purse includes a $5 million Second Prize and bonus prizes for specific objectives such as lunar night survival and visiting historic sites. Of the 29 teams that entered the race, 18 are still progressing. Google Lunar XPRIZE recently added Milestone Prizes totaling up to $6 million for meeting 2014 technical milestones in three categories: Landing, Mobility and Imaging. Astrobotic and Moon Express are the only two teams to advance to the Accomplishment Round in all three categories.

NASA has also played a crucial role. In 2010, NASA committed a total of $30 million in Innovative Lunar Demonstrations Data (ILDD) contracts to six companies — including Astrobotic — to purchase the technical data from the development of robotic lunar landings. In February 2014, NASA announced the Lunar Cargo Transportation and Landing by Soft Touchdown(Lunar CATALYST) initiative, which seeks a commercial partner to develop robotic lunar lander capabilities. To date, NASA has awarded 15 contracts to Astrobotic, most of which have contributed toward Astrobotic's development of lunar mission capability.

Instead of treating payload customers with modest budgets as "secondary payload," Astrobotic focuses its mission operations on supporting them. We charge $1.2 million per kilogram to carry from 1 kg to 270 kg of payload to the lunar surface on our Griffin lander, with lower-cost options for payloads that separate from us en route. We have two dozen payloads interested in our first mission, which together exceed our capacity. Prospective customers include NASA and smaller-government space programs, commercial ventures and other Google Lunar XPRIZE teams.

A SpaceX Falcon 9 launch vehicle places Griffin into trans-lunar injection, a trajectory that will swing by the moon. This provides enough of the mission's total energy requirement that the single-stage Griffin lander can do the rest, greatly simplifying the overall mission.

Griffin then navigates along a pre-planned trajectory and performs a braking maneuver to enter lunar orbit. Up to this point, the mission relies on integration of off-the-shelf subsystems and techniques that have been developed and well tested for Earth orbit, from the launch to communications, propulsion, radio triangulation, a star tracker and an inertial measurement unit (IMU).

Griffin performs another braking maneuver to leave lunar orbit and begin its initial descent. It is at this point that Griffin departs the comfortable technological ecosystem of Earth-orbit subsystems and must rely on new capabilities developed at Astrobotic.

Astrobotic's first mission will land and explore the moon's Lacus Mortis region. Latin for "Lake of Death," Lacus Mortis is a plain of basaltic lava flows. It contains a pit that is a compelling exploration target. The pit's east wall has partially collapsed, creating an inviting ramp that could someday be traversed by a robotic rover.
The combination of radio triangulation, star tracker and IMU work well for orbit, but are not precise enough for safe landing near a pit. Terrestrial, unmanned aerial vehicles rely heavily on GPS, but that isn't an option on the moon. Instead, Astrobotic has developed proprietary vision algorithms that track the lander's position and attitude.

Griffin's autolanding system differs in several ways from systems like NASA's Autonomous Landing Hazard Avoidance Technology (ALHAT), which is designed to deliver people to the lunar surface. Griffin's autolanding system makes decisions entirely without human input. 

The small ground clearance typical of robotic landers requires the capability to detect tiny objects on the surface. To reduce mass, the system uses sensors with fixed pointing to provide the needed views of the surface and relies more heavily on cameras for precise location information. We rely on the precisely located, high-resolution image maps of the lunar surface from NASA orbital missions. The autolanding system is low-power, lightweight and highly accurate.

This landing approach has two significant challenges. The vision algorithms needed to achieve landing didn't exist — we had to invent them ourselves. Furthermore, the computing required to execute these algorithms doesn't exist in a form that is viable for operation in the vacuum of space. One of our Milestone Prize deliverables is demonstration of our own flight-capable computing system.

We recently demonstrated our landing approach on a vertical-takeoff, vertical-landing rocket. The rocket carried Griffin's sensors through the final descent portion of our landing trajectory, descending rapidly from 250 meters altitude, braking, and then entering a constant-velocity glide slope. As the rocket descended, Griffin's sensors scanned the ground to detect hazards and select a safe landing point. We had a flawless flight.

When we reach the lunar surface, we face new challenges. A lunar rover must have very low mass, be power efficient, and navigate rough terrain with no chance of rescue. The most difficult challenges are thermal. On Earth, the atmosphere blocks much of the sun's radiation and air provides cooling. A lunar rover operates in direct sunlight in a vacuum, where heat can only be dissipated by radiation or direct conduction. Operating terrestrial electronics in this environment would be like wrapping a laptop in blankets and running it full-bore. To complicate matters, the regolith under the rover heats to above the boiling point of water at lunar noon and drops to cryogenic temperatures at night.

In collaboration with Carnegie Mellon University and with NASA funding, we experimented to identify electronics that can survive the heat of the day and the cold of the night. Our rover architecture reflects most of the incoming radiation from the sun and the regolith, and radiates heat toward cold sky so we can operate through the hottest parts of the day.

The Google Lunar XPRIZE requires that we transmit two "mooncasts" back to Earth. This requires obtaining the necessary image resolution (720p in color) with a low-mass camera that can both withstand the shock and vibration of launch and operate in the vacuum and temperature extremes of the lunar surface. Communicating high-resolution images back to Earth is a significant challenge because of the distances involved; because the rover is so power limited, we relay imagery through the lander.

Like a modern-day Columbus, the Apollo astronauts gave us our first close-up glimpse of new territory and fired our imaginations. Now it's time for industry to return, still with excitement, but also with pragmatism. The moon offers a wealth of new knowledge of our planet and our solar system. It can teach us how to operate on a planetary surface. At some point, it will yield valuable resources. First, we have to make it a routine part of commercial space.

Source of Article: Space.com
John Thornton, CEO, Astrobotic Technology