NASA’s Jet Propulsion Laboratory recently announced that it is developing a small drone helicopter to scout the way for future Mars rovers. Why would Mars rovers need such a robotic guide? The answer is that driving on Mars is really hard.
Here on Earth, robots exploring volcanic rims, or assisting rescuers, can be driven by remote control, with a joystick. This is because radio signals reach the robot from its control center almost instantly. Driving on the moon isn’t much harder. Radio signals traveling at the speed of light take about two and half seconds to make the round trip to the moon and back. This delay isn’t long enough to seriously interfere with remote control driving. In the 1970’s Soviet controllers drove the Lunokhod moon rovers this way, successfully exploring more than 40 km of lunar terrain.
Driving on Mars is much harder, because it is so much further away. Depending on its position with respect to Earth, signals can take between 8 and 42 minutes for the round trip. Pre-programmed instructions must be sent to the rover, which it then executes on its own. Each Martian drive takes hours of careful planning. Stereo images taken by the rover’s navigation cameras are carefully scrutinized by engineers. Images from spacecraft orbiting Mars sometimes provide additional information.
A rover can be programmed either to simply execute a list of driving commands sent from Earth, or it can use images taken by its navigation cameras and processed by its on-board computers to measure speed and detect obstacles or hazards by itself. It can even plot its own safe path to a specified goal. Drives based on instructions from the ground are the fastest.
The Mars Exploration Rovers Spirit and Opportunity could drive up to 124 meters in an hour this way. This corresponds to about the length of an American football field. But this mode was also the least safe.
When the rover actively guides itself with its cameras, progress is safer, but much slower because of all the image processing needed. It may progress by as little as 10 meters an hour, which is about the distance from the goal line to the 10 yard line on an American football field. This method must be used whenever the rover doesn’t have a clear view of the route ahead, which is often the case due to rough and hilly terrain.
As of early 2015, the farthest Curiosity has driven in a single day is 144 meters. Opportunity’s longest daily drive was 224 meters, a distance the length of two American football fields.
If ground controllers could get a better view of the path ahead, they could devise instructions allowing a future rover to safely drive much further in a day.
That’s where the idea of a drone helicopter comes in. The helicopter could fly out ahead of the rover every day. Images made from its aerial vantage point would be invaluable to ground controllers for identifying points of scientific interest, and planning driving routes to get there.
Flying a helicopter on Mars poses special challenges. One advantage is that Martian gravity is only 38% as strong as that of Earth, so that the helicopter wouldn’t need to generate as much lift as one of the same mass on Earth. A helicopter’s propeller blades generate lift by pushing air downward. This is harder to do on Mars than on Earth, because the Martian atmosphere is on hundred times thinner. To displace enough air, the propeller blades would need to spin very quickly, or to be very large.
The copter must be capable of flying on its own, using prior instructions, maintaining stable flight along a pre-specified route. It must land and take off repeatedly in rocky Martian terrain. Finally it must be capable of surviving the harsh conditions of Mars, where the temperature plummets to 100 degrees Fahrenheit or lower every night.
The JPL engineers designed a copter with a mass of 1 kilogram; a tiny fraction of the 900 kg mass of the Curiosity rover. Its propeller blades span 1.1 meters from blade tip to blade tip, and are capable of spinning at 3400 rotations per minute. The body is about the size of a tissue box.
The copter is solar powered, with a disk of solar cells gathering enough power every day to power a flight of two to three minutes and to heat the vehicle at night. It can fly about half a kilometer in that time, gathering images for transmission to ground control as it goes. Engineers expect that the reconnaissance that the drone copter gathers will be invaluable in planning a rover’s drives, tripling the distance that can be traveled in a day.
References and further reading:
Thanks to Mark Maimone of NASA Jet Propulsion Laboratory for information about the daily driving distances of Curiosity and Opportunity.
What is up with the fossils on Mars? Found – a dinosaur skull on Mars? Discovered – a rat, squirrel or gerbil on Mars? In background of images from Curiosity, vertebrae from some extinct Martian species? And the human skull, half buried in photos from Opportunity Rover. All the images are made of stone from the ancient past and this is also what is called Pareidolia. They are figments of our imaginations, and driven by our interest to be there – on Mars – and to know that we are not alone. Altogether, they make a multitude of web pages and threads across the internet.
Rock-hounds and Martian paleontologists, if only amateur or retired, have found a bounty of fascinating rocks nestled among the rocks on Mars. There are impressive web sites dedicated to each’s eureka moment, dissemination among enthusiasts and presentation for discussion.
NASA scientists have sent the most advanced robotic vehicles to the surface of Mars, to the most fascinating and diverse areas that are presently reachable with our technology and landing skills. The results have been astounding scientifially but also in terms of mysteries and fascination with the strange, alien formations. Some clearly not unlike our own and others that must be fossil remnants from a bygone era – so it seems.
Be sure to explore, through the hyperlinks, many NASA, NASA affiliates’ and third party websites – embedded throughout this article. Also, links to specific websites are listed at the end of the article.
The centerpiece of recent interest is the dinosaur skull protruding from the Martian regolith, teeth still embedded, sparkling efferdent white. There are no sockets for these teeth. Dinosaur dentures gave this senior citizen a few extra good years. The jaw line of the skull has no joint or connection point with the skull. So our minds make up the deficits, fill in the blanks and we agree with others and convince ourselves that this is a fossilized skull. Who knows how this animal could have evolved differently.
But evolve it did – within our minds. Referencing online dictionaries [ref], “Pareidolia is the imagined perception of a pattern (or meaning) where it does not actually exist, as in considering the moon to have human features.” I must admit that I do not seek out these “discoveries” on Mars but I enjoy looking at them and there are many scientists at JPL that have the same bent. Mars never fails to deliver and caters to everyone, but when skulls and fossils are seen, it is actually us catering to the everyday images and wishes we hold in our minds.
The “Rat on Mars” (main figure, top center) is actually quite anatomically complete and hunkered down, having taken its final gasps of air, eons ago, as some cataclysmic event tore the final vestiges of Earth-like atmosphere off the surface. It died where it once roamed and foraged for … nuts and berries? Surprisingly, no nuts have been found. Blueberries – yes – they are plentiful on Mars and could have been an excellent nutritional source for rats; high in iron and possibly like their Earthly counterpart, high in anti-oxidants.
The blueberries were popularized by Dr. Steve Squyres, the project scientist of the Mars Exploration Rover (MER) mission. Discovered in Eagle crater and across Meridiani Planum, “Blueberries” are spherules of concretions of iron rich minerals from water. It is a prime chapter in the follow-the-water story of Mars. And not far from the definition of Pareidolia, Eagle Crater refers to the incredible set of landing bounces that sent “Oppy” inside its capsule, surrounded by airbags on a hole-in-one landing into that little crater.
Next, is the face of Mars of the Cydonia region (Images of Cydonia, Mars, NSSDC). As seen in the morphed images, above, the lower resolution Viking orbiter images presented Mars-o-philes clear evidence of a lost civilization. Then, Washington handed NASA several years of scant funding for planetary science, and not until Mars Global Surveyor, was the Face of Cydonia photographed again. The Mars Orbiter Camera from the University of Arizona delivered high resolution images that dismissed the notion of a mountain-sized carving. Nonetheless, this region of Mars is truly fascinating geologically and does not disappoint those in search of past civilizations.
And long before the face on Mars in Cydonia, there were the canals of Mars. Spotted by the Mars observer Schiaparelli, the astronomer described them as “channels” in his native language of Italian. The translation of the word turned to “Canals” in English which led the World to imagine that an advanced civilization existed on Mars. Imagine if you can for a moment, this world without Internet or TV or radio and even seldom a newspaper to read. When news arrived, people took it verbatim. Canals, civilizations – imagine how imaginations could run with this and all that actually came from it. It turns out that the canals or channels of Mars as seen with the naked eye were optical illusions and a form of Pareidolia.
So, as our imagery from Mars continues to return in ever greater detail and depth, scenes of pareidolia will fall to reason and we are left with understanding. It might seem sterile and clinical but its not. We can continue to enjoy these fascinating rocks – dinosaurs, rats, skulls, human figures – just as we enjoy a good episode of Saturday Night Live. And neither the science or the pareidolia should rob us of our ability to see the shear beauty of Mars, the fourth rock from the Sun.
In the article’s main image, what should not be included is the conglomerate rock on Mars. NASA/JPL scientists and geologists quickly recognized this as another remnant of Martian hydrologics – the flow of water and specifically, the bottom of a stream bed (NASA Rover Finds Old Streambed on Martian Surface). Truly a remarkable discovery and so similar to conglomerate rocks on Earth.
A quarter of a century has passed since NASA’s Voyager 1 spacecraft snapped the iconic image of Earth known as the “Pale Blue Dot” that shows all of humanity as merely a tiny point of light.
The outward bound Voyager 1 space probe took the ‘pale blue dot’ image of Earth 25 years ago on Valentine’s Day, on Feb. 14, 1990 when it looked back from its unique perch beyond the orbit of Neptune to capture the first ever “portrait” of the solar system from its outer realms.
Voyager 1 was 4 billion miles from Earth, 40 astronomical units (AU) from the sun and about 32 degrees above the ecliptic at that moment.
The idea for the images came from the world famous astronomer Carl Sagan, who was a member of the Voyager imaging team at the time.
He head the idea of pointing the spacecraft back toward its home for a last look as a way to inspire humanity. And to do so before the imaging system was shut down permanently thereafter to repurpose the computer controlling it, save on energy consumption and extend the probes lifetime, because it was so far away from any celestial objects.
Sagan later published a well known and regarded book in 1994 titled “Pale Blue Dot,” that refers to the image of Earth in Voyagers series.
“Twenty-five years ago, Voyager 1 looked back toward Earth and saw a ‘pale blue dot,’ ” an image that continues to inspire wonderment about the spot we call home,” said Ed Stone, project scientist for the Voyager mission, based at the California Institute of Technology, Pasadena, in a statement.
Six of the Solar System’s nine known planets at the time were imaged, including Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The other three didn’t make it in. Mercury was too close to the sun, Mars had too little sunlight and little Pluto was too dim.
Voyager snapped a series of images with its wide angle and narrow angle cameras. Altogether 60 images from the wide angle camera were compiled into the first “solar system mosaic.”
Voyager 1 was launched in 1977 from Cape Canaveral Air Force Station in Florida as part of a twin probe series with Voyager 2. They successfully conducted up close flyby observations of the gas giant outer planets including Jupiter, Saturn, Uranus and Neptune in the 1970s and 1980s.
Both probes still operate today as part of the Voyager Interstellar Mission.
“After taking these images in 1990, we began our interstellar mission. We had no idea how long the spacecraft would last,” Stone said.
Hurtling along at a distance of 130 astronomical units from the sun, Voyager 1 is the farthest human-made object from Earth.
Voyager 1 still operates today as the first human made instrument to reach interstellar space and continues to forge new frontiers outwards to the unexplored cosmos where no human or robotic emissary as gone before.
Here’s what Sagan wrote in his “Pale Blue Dot” book:
“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
The Obama Administration today (Feb. 2) proposed a NASA budget allocation of $18.5 Billion for the new Fiscal Year 2016, which amounts to a half-billion dollar increase over the enacted budget for FY 2015, and keeps the key manned capsule and heavy lift rocket programs on track to launch humans to deep space in the next decade and significantly supplements the commercial crew initiative to send our astronauts to low Earth orbit and the space station later this decade.
NASA Administrator Charles Bolden formally announced the rollout of NASA’s FY 2016 budget request today during a “state of the agency” address at the Kennedy Space Center (KSC), back dropped by the three vehicles at the core of the agency’s human spaceflight exploration strategy; Orion, the Boeing CST-100 and the SpaceX Dragon.
“To further advance these plans and keep on moving forward on our journey to Mars, President Obama today is proposing an FY 2016 budget of $18.5 billion for NASA, building on the significant investments the administration has made in America’s space program over the past six years,” Administrator Bolden said to NASA workers and the media gathered at the KSC facility where Orion is being manufactured.
“These vehicles are not things just on paper anymore! This is tangible evidence of what you [NASA] have been doing these past few years.”
Bolden said the $18.5 Billion budget request will enable the continuation of core elements of NASA’s main programs including first launch of the new commercial crew vehicles to orbit in 2017, maintaining the Orion capsule and the Space Launch System (SLS) rocket to further NASA’s initiative to send ‘Humans to Mars’ in the 2030s, extending the International Space Station (ISS) into the next decade, and launching the James Webb Space Telescope in 2018. JWST is the long awaited successor to NASA’s Hubble Space Telescope.
“NASA is firmly on a journey to Mars. Make no mistake, this journey will help guide and define our generation.”
Funding is also provided to enable the manned Asteroid Redirect Mission (ARM) by around 2025, to continue development of the next Mars rover, and to continue formulation studies of a robotic mission to Jupiter’s icy moon Europa.
“That’s a half billion-dollar increase over last year’s enacted budget, and it is a clear vote of confidence in you – the employees of NASA – and the ambitious exploration program you are executing,” said Bolden.
Overall the additional $500 million for FY 2016 translates to a 2.7% increase over FY 2015. That compares to about a 6.4% proposed boost for the overall US Federal Budget amounting to $4 Trillion.
The Boeing CST-100 and the SpaceX Dragon V2 will restore the US capability to ferry astronauts to and from the International Space Station (ISS).
In September 2014, Bolden announced the selections of Boeing and SpaceX to continue development and certification of their proposed spaceships under NASA’s Commercial Crew Program (CCP) and Launch America initiative started back in 2010.
Since the retirement of the Space Shuttle program in 2011, all NASA astronauts have been totally dependent on Russia and their Soyuz capsule as the sole source provider for seats to the ISS.
“The commercial crew vehicles are absolutely critical to our journey to Mars, absolutely critical. SpaceX and Boeing have set up operations here on the Space Coast, bringing jobs, energy and excitement about the future with them. They will increase crew safety and drive down costs.”
CCP gets a hefty and needed increase from $805 Million in FY 2015 to $1.244 Billion in FY 2016.
To date the Congress has not fully funded the Administration’s CCP funding requests, since its inception in 2010.
The significant budget slashes amounting to 50% or more by Congress, have forced NASA to delay the first commercial crew flights of the private ‘space taxis’ from 2015 to 2017.
As a result, NASA has also been forced to continue paying the Russians for crew flights aboard the Soyuz that now cost over $70 million each under the latest contract signed with Roscosmos, the Russian Federal Space Agency.
Bolden has repeatedly stated that NASA’s overriding goal is to send astronauts to Mars in the 2030s.
To accomplish the ‘Journey to Mars’ NASA is developing the Orion deep space crew capsule and mammoth SLS rocket.
However, both programs had their budgets cut in the FY 2016 proposal compared to FY 2015. The 2015 combined total of $3.245 Billion is reduced in 2016 to $2.863 Billion, or over 10%.
The first test flight of an unmanned Orion atop the SLS is now slated for liftoff on Nov. 2018, following NASA’s announcement of a launch delay from the prior target of December 2017.
Since the Journey to Mars goal is already underfunded, significant cuts will hinder progress.
Rather incomprehensibly funding for the long lived Opportunity Mars Exploration Rover is zeroed out in 2016.
This comes despite the fact that the renowned robot just reached the summit of a Martian mountain at Cape Tribulation and is now less than 200 meters from a science goldmine of water altered minerals.
Funding for the Lunar Reconnaissance Orbiter (LRO) is also zeroed out in FY 2016.
Both missions continue to function quite well with very valuable science returns. They were also zeroed out in FY 2015 but received continued funding after a senior level science review.
So their ultimate fate is unknown at this time.
Overall, Bolden was very upbeat about NASA’s future.
“I can unequivocally say that the state of NASA is strong,” Bolden said.
He concluded his remarks saying:
“Because of the dedication and determination of each and every one of you in our NASA Family, America’s space program is not just alive, it is thriving! Together with our commercial and international partners, academia and entrepreneurs, we’re launching the future. With the continued support of the Administration, the Congress and the American people, we’ll all get there together.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
NASA’s Soil Moisture Active Passive (SMAP) observatory, on a United Launch Alliance Delta II rocket, is seen after the mobile service tower was rolled back Friday, Jan. 30 at Space Launch Complex 2, Vandenberg Air Force Base, Calif. Image Credit: NASA/Bill Ingalls
Story updated[/caption]
At dawn this morning (Jan. 31) NASA launched an advanced Earth science satellite aimed at making measurements of our planet’s surface soil moisture and freeze/thaw states from space that will revolutionize our understanding of the water, energy, and carbon cycles driving all life on Earth, aid weather forecasting and improve climate change models.
NASA’s new Soil Moisture Active Passive (SMAP) observatory thundered off the pad at 6:22 a.m. PST (9:22 a.m. EST) Saturday atop a two stage United Launch Alliance Delta II rocket from Space Launch Complex 2 on Vandenberg Air Force Base, California.
The $916 million satellite successfully separated from the rocket’s second stage some 57 minutes after the flawless liftoff and was injected into an initial 411- by 425-mile (661- by 685-kilometer) orbit. The spacecraft then deployed its solar arrays and telemetry indicated it was in excellent health.
“We’re in contact with SMAP and everything looks good right now,” NASA Launch Manager Tim Dunn said.
“Deployment of the solar arrays is underway. We just couldn’t be happier.”
SMAP separated from the second stage while pointed toward the sun as seen in the video below from a rocket mounted camera:
Video Caption: A camera on the second stage of the Delta II rocket captured this footage as the SMAP spacecraft pushed itself away from the rocket to complete the delivery of the Earth-observing spacecraft to its proper orbit following Jan. 31, 2015 liftoff. Credit: NASA TV/ULA
SMAP is NASA’s 1st Earth observing satellite designed to make high resolution global observations of Earth’s vital surface soil moisture content and freeze/thaw cycle just below your feet. It will aid global forecasting and have broad applications for science and society.
SMAP’s combined radar and radiometer instruments will peer into the top 2 inches (5 centimeters) of soil, through clouds and moderate vegetation cover, day and night, to produce the highest-resolution, most accurate soil moisture maps ever obtained from space, says NASA.
The blastoff of SMAP successfully concluded NASA’s ambitious plans to launch a record breaking total of five Earth science satellites in less than a year’s time.
“The launch of SMAP completes an ambitious 11-month period for NASA that has seen the launch of five new Earth-observing space missions to help us better understand our changing planet,” said NASA Administrator Charles Bolden.
“Scientists and policymakers will use SMAP data to track water movement around our planet and make more informed decisions in critical areas like agriculture and water resources.”
SMAP is projected to last for at least a three year primary mission.
The prior NASA Earth science instrument launched was the Cloud Aerosol Transport System (CATS) payload hauled to space by the SpaceX CRS-4 Dragon on Jan. 10, 2015 and recently installed on the exterior of the ISS. Read my CATS installation story – here.
“Congratulations to the NASA Launch Services Program team, JPL and all of our mission partners on today’s successful launch of the SMAP satellite,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs.
“It is our honor to launch this important Earth science mission to help scientists observe and predict natural hazards, and improve our understanding of Earth’s water, energy and carbon cycles.”
SMAP will provide high-resolution, space-based measurements of soil moisture and its state — frozen or thawed — a new capability that will allow scientists to better predict natural hazards of extreme weather, climate change, floods and droughts, and help reduce uncertainties in our understanding of Earth’s water, energy and carbon cycles, according to a NASA description.
The mission will map the entire globe every two to three days for at least three years and provide the most accurate and highest-resolution maps of soil moisture ever obtained. The spacecraft’s final circular polar orbit will be 426 miles (685 kilometers), at an inclination of 98.1 degrees. The spacecraft will orbit Earth once every 98.5 minutes and repeat the same ground track every eight days.
“All subsystems are being powered on and checked out as planned,” Kent Kellogg, the SMAP project manager, during a post-launch press conference.
“Communications, guidance and control, computers and power are all operating nominally.”
The observatory is in excellent health. Its instruments will be turned on in 11 days.
Today’s blastoff of SMAP marks ULA’s second successful launch this month as well as the second of 13 planned for 2015. ULA’s first launch of 2015 was MUOS-3 from Cape Canaveral on Jan. 20.
ULA’s next launch involves NASA’s Magnetospheric Multiscale Mission (MMS) to study Earth’s magnetic reconnection. It is scheduled for launch on an Atlas V 421 booster on March 12 from Cape Canaveral. See my up close visit with MMS and NASA Administrator Charles Bolden at NASA Goddard Space Flight Center detailed in my story – here.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Barely two months after being launched to the International Space Station (ISS), NASA’s first science payload aimed at conducting Earth science from the station’s exterior has started its ocean wind monitoring operations two months ahead of schedule.
Data from the ISS Rapid Scatterometer, or ISS-RapidScat, payload is now available to the world’s weather and marine forecasting agencies following the successful completion of check out and calibration activities by the mission team.
Indeed it was already producing high quality, usable data following its power-on and activation at the station in late September and has monitored recent tropical cyclones in the Atlantic and Pacific Oceans prior to the end of the current hurricane season.
RapidScat is designed to monitor ocean winds for climate research, weather predictions, and hurricane monitoring for a minimum mission duration of two years.
“RapidScat is a short mission by NASA standards,” said RapidScat Project Scientist Ernesto Rodriguez of JPL.
“Its data will be ready to help support U.S. weather forecasting needs during the tail end of the 2014 hurricane season. The dissemination of these data to the international operational weather and marine forecasting communities ensures that RapidScat’s benefits will be felt throughout the world.”
The 1280 pound (580kilogram) experimental instrument was developed by NASA’s Jet Propulsion Laboratory. It’s a cost-effective replacement to NASA’s former QuikScat satellite.
The $26 million remote sensing instrument uses radar pulses reflected from the ocean’s surface at different angles to calculate the speed and direction of winds over the ocean for the improvement of weather and marine forecasting and hurricane monitoring.
The RapidScat, payload was hauled up to the station as part of the science cargo launched aboard the commercial SpaceX Dragon CRS-4 cargo resupply mission that thundered to space on the company’s Falcon 9 rocket from Space Launch Complex-40 at Cape Canaveral Air Force Station in Florida on Sept. 21.
ISS-RapidScat is NASA’s first research payload aimed at conducting near global Earth science from the station’s exterior and will be augmented with others in coming years.
It was robotically assembled and attached to the exterior of the station’s Columbus module using the station’s robotic arm and DEXTRE manipulator over a two day period on Sept 29 and 30.
Ground controllers at Johnson Space Center intricately maneuvered DEXTRE to pluck RapidScat and its nadir adapter from the unpressurized trunk section of the Dragon cargo ship and attached it to a vacant external mounting platform on the Columbus module holding mechanical and electrical connections.
The nadir adapter orients the instrument to point its antennae at Earth.
The couch sized instrument and adapter together measure about 49 x 46 x 83 inches (124 x 117 x 211 centimeters).
“The initial quality of the RapidScat wind data and the timely availability of products so soon after launch are remarkable,” said Paul Chang, ocean vector winds science team lead at NOAA’s National Environmental Satellite, Data and Information Service (NESDIS)/Center for Satellite Applications and Research (STAR), Silver Spring, Maryland.
“NOAA is looking forward to using RapidScat data to help support marine wind and wave forecasting and warning, and to exploring the unique sampling of the ocean wind fields provided by the space station’s orbit.”
This has been a banner year for NASA’s Earth science missions. At least five missions will be launched to space within a 12 month period, the most new Earth-observing mission launches in one year in more than a decade.
ISS-RapidScat is the third of five NASA Earth science missions scheduled to launch over a year.
NASA has already launched the of the Global Precipitation Measurement (GPM) Core Observatory, a joint mission with the Japan Aerospace Exploration Agency, in February and the Orbiting Carbon Observatory-2 (OCO-2) carbon observatory in July 2014.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
We are now in the final hours before Rosetta’s Philae lander is released to attempt a first-ever landing on a comet. At 9:03 GMT (1:03 AM PST) on Wednesday, November 12, 2014, Philae will be released and directed towards the surface of comet 67P/Churyumov–Gerasimenko. 7 hours later, the lander will touch down.
Below you’ll find a timeline of events, info on how to watch the landing, and an overview of how the landing will (hopefully) work.
In human affairs, we build contingencies for missteps, failures. With spacecraft, engineers try to eliminate all single point failures and likewise have contingency plans. The landing of a spacecraft, be it on Mars, Earth, or the Moon, always involves unavoidable single point failures and points of no return, and with comet 67P/Churyumov–Gerasimenko, Rosetta’s Philae lander is no exception.
Rosetta’s and Philae’s software and hardware must work near flawlessly to give Philae the best chance possible of landing safely. And even with flawless execution, it all depends on Philae’s intercepting a good landing spot on the surface. Philae’s trajectory is ballistic on this one way trip to a comet’s surface. It’s like a 1 mile per hour bullet. Once fired, it’s on its own, and for Philae, its trajectory could lead to a pristine flat step or it could be crevasse, ledge, or sharp rock.
The accuracy of the landing is critical but it has left a 1 square kilometer of uncertainty. For this reason, engineers and scientists had to survey the whole surface for the most mild features. Comet 67P has few areas that are not extreme in one way or another. Site J, now called Agilkia, is one such site.
When first announced in late September, the time of release was 08:35 GMT (12:35 AM PST). Now the time is 9:03 GMT. The engineers and computer scientists have had six weeks to further refine their trajectory. It’s a complicated calculation that has required running the computer simulation of the descent backwards. Backwards because they can set a landing time then run Philae backwards to the moment of release. The solution is not just one but many, thousands or millions if you want to look in such detail. With each release point, the engineers had to determine how, or if, Rosetta could be navigated to that coordinate point in space and time.
Arrival time of the radio signal with landing status: 16:30 GMT
Rosetta/Philae at 500 million km [320 million miles], 28.5 minutes light time
Arrival of First Images: 06:00 GMT, November 13, 2014
The gravity field of the comet is so weak, it is primarily the initial velocity from Rosetta that delivers Philae to the surface. But the gravity is there and because of the chaotic shape and unknown (as yet) mass distribution inside, the gravity will make Philae move like a major league knuckleball wobbling to the plate and a batter. Furthermore, the comet during the seven hour trip will make half a rotation. The landing site will not be in site when Philae is released.
And as Philae is on final approach, it will use a small rocket not to slow down but rather thrust it at the comet, landing harpoons will be fired, foot screws will try to burrow into the comet, and everyone on Earth will wait several minutes for a message to be relayed from Philae to Rosetta to the Deep Space Network (DSN) antennas on Earth. Philae will be on its own as soon as it leaves Rosetta and its fate is a few hours away.
Why travel to a comet? Comets represent primordial material leftover from the formation of the solar system. Because cometary bodies were formed and remained at a distance from the heat of the sun, the materials have remained nearly unchanged since formation, ~4.5 billion years ago. By looking at Rosetta’s comet, 67P/Churyumov–Gerasimenko, scientists will gain the best yet measurements of a comet’s chemical makeup, its internal structure created during formation, and the dynamics of the comet as it approaches the warmth of the Sun. Theories propose that comets impacting on Earth delivered most of the water of our oceans. If correct, then we are not just made of star-stuff, as Carl Sagan proclaimed, we are made of comet stuff, too. Comets may also have delivered the raw organic materials needed to start the formation of life on Earth.
Besides the ESA live feeds, one can take a peek at NASA’s Deep Space Network (DSN) at work to see which telescopes are communicating with Rosetta. JPL’s webcast can watched below:
Looks like we dodged a bullet. A bullet-shaped asteroid that is. The 70-meter Goldstone radar dish, part of NASA’s Deep Space Network, grabbed a collage of photos of Earth-approaching asteroid 2014 SC324 during its close flyby last Friday October 24. These are the first-ever photos of the space rock which was discovered September 30 this year by the Mt. Lemmon Survey. The level of detail is amazing considering that the object is only about 197 feet (60-meters) across. You can also see how incredibly fast it’s rotating – about 30-45 minutes for a one spin.
In the cropped version, the shape is somewhat clearer with the asteroid appearing some four times longer than wide. 2014 SC324 belongs to the Apollo asteroid class, named for 1862 Apollo discovered in 1932 by German astronomer Karl Reinmuth. Apollo asteroids follow orbits that occasionally cross that of Earth’s, making them a potential threat to our planet. The famed February 15, 2013 Chelyabinsk fireball, with an approximate pre-atmospheric entry size of 59 feet (18-m), belonged to the Apollo class.
Lance Benner and colleagues at Goldstone also imaged another Apollo asteroid that passed through our neighborhood on October 19 called 2014 SM143. This larger object, estimated at around 650 feet (200-m) across, was discovered with the Pan-STARRS 1 telescope on Mt. Haleakala in Hawaii on September 17. Tell me we’re not some shiny ball on a solar system-sized pool table where the players fortunately miss their shot … most of the time.
NASA inaugurated a new era of research for the International Space Station (ISS) as an Earth observation platform following the successful installation and activation of the ISS-RapidScat science instrument on the outposts exterior at Europe’s Columbus module.
The ISS Rapid Scatterometer, or ISS-RapidScat, is NASA’s first research payload aimed at conducting near global Earth science from the station’s exterior and will be augmented with others in coming years.
RapidScat is designed to monitor ocean winds for climate research, weather predictions, and hurricane monitoring.
The 1280 pound (580 kilogram) experimental instrument is already collecting its first science data following its recent power-on and activation at the station.
“Its antenna began spinning and it started transmitting and receiving its first winds data on Oct.1,” according to a NASA statement.
The first image from RapidScat was released by NASA on Oct. 6, shown below, and depicts preliminary measurements of global ocean near-surface wind speeds and directions.
The $26 million remote sensing instrument uses radar pulses to observe the speed and direction of winds over the ocean for the improvement of weather forecasting.
“Most satellite missions require weeks or even months to produce data of the quality that we seem to be getting from the first few days of RapidScat,” said RapidScat Project Scientist Ernesto Rodriguez of NASA’s Jet Propulsion Laboratory, Pasadena, California, which built and manages the mission.
“We have been very lucky that within the first days of operations we have already been able to observe a developing tropical cyclone.
“The quality of these data reflect the level of testing and preparation that the team has put in prior to launch,” Rodriguez said in a NASA statement. “It also reflects the quality of the spare QuikScat hardware from which RapidScat was partially assembled.”
RapidScat, payload was hauled up to the station as part of the science cargo launched aboard the commercial SpaceX Dragon CRS-4 cargo resupply mission that thundered to space on the company’s Falcon 9 rocket from Space Launch Complex-40 at Cape Canaveral Air Force Station in Florida on Sept. 21.
Dragon was successfully berthed at the Earth-facing port on the station’s Harmony module on Sept 23, as detailed here.
It was robotically assembled and attached to the exterior of the station’s Columbus module using the station’s robotic arm and DEXTRE manipulator over a two day period on Sept 29 and 30.
Ground controllers at Johnson Space Center intricately maneuvered DEXTRE to pluck RapidScat and its nadir adapter from the unpressurized trunk section of the Dragon cargo ship and attached it to a vacant external mounting platform on the Columbus module holding mechanical and electrical connections.
The nadir adapter orients the instrument to point at Earth.
The couch sized instrument and adapter together measure about 49 x 46 x 83 inches (124 x 117 x 211 centimeters).
Engineers are in the midst of a two week check out process that is proceeding normally so far. Another two weeks of calibration work will follow.
Thereafter RapidScat will begin a mission expected to last at least two years, said Steve Volz, associate director for flight programs in the Earth Science Division, NASA Headquarters, Washington, at a prelaunch media briefing at the Kennedy Space Center.
RapidScat is the forerunner of at least five more Earth science observing instruments that will be added to the station by the end of the decade, Volz explained.
The second Earth science instrument, dubbed CATS, could be added by year’s end.
The Cloud-Aerosol Transport System (CATS) is a laser instrument that will measure clouds and the location and distribution of pollution, dust, smoke, and other particulates in the atmosphere.
CATS is slated to launch on the next SpaceX resupply mission, CRS-5, currently targeted to launch from Cape Canaveral, FL, on Dec. 9.
This has been a banner year for NASA’s Earth science missions. At least five missions will be launched to space within a 12 month period, the most new Earth-observing mission launches in one year in more than a decade.
ISS-RapidScat is the third of five NASA Earth science missions scheduled to launch over a year.
Learn more about Commercial Space Taxis, Orion and NASA Human and Robotic Spaceflight at Ken’s upcoming presentations:
Oct 14: “What’s the Future of America’s Human Spaceflight Program with Orion and Commercial Astronaut Taxis” & “Antares/Cygnus ISS Rocket Launches from Virginia”; Princeton University, Amateur Astronomers Assoc of Princeton (AAAP), Princeton, NJ, 7:30 PM
Oct 23/24: “Antares/Cygnus ISS Rocket Launch from Virginia”; Rodeway Inn, Chincoteague, VA
Ask any space enthusiast, and almost anyone will say humankind’s ultimate destination is Mars. But NASA is currently gearing up to go to an asteroid. While the space agency says its Asteroid Initiative will help in the eventual goal of putting people on Mars, what if instead of going to an asteroid, we went to Mars’ moon Phobos?
Three prominent planetary scientists have joined forces in a new paper in the journal Planetary and Space Science to explain the case for a mission to the moons of Mars, particularly Phobos.
“Phobos occupies a unique position physically, scientifically, and programmatically on the road to exploration of the solar system,” say the scientists. In addition, the moons may possibly be a source of in situ resources that could support future human exploration in circum-Mars space or on the Martian surface. But a sample return mission first could provide details on the moons’ origins and makeup.
The Martian moons are riddles, wrapped in a mystery, inside an enigma.Phobos and its sibling Deimos seem like just two asteroids which were captured by the planet Mars, and they remain the last objects of the inner solar system not yet studied with a dedicated mission. But should the moons be explored with flybys or sample-return? Should we consider “boots or bots”?
The publications and mission concepts for Phobos and Deimos are numerous and go back decades. The authors of “The Value of a Phobos Sample Return,” Murchie, Britt, and Pieters, explore the full breadth of questions of why and how to explore Phobos and Deimos.
Dr. Murchie is the principal investigator of the Mars Reconnaissance Orbiter’s CRISM instrument, a visible/infrared imaging spectrometer. He is a planetary scientist from John Hopkins’ Applied Physics Lab (APL) which has been at the forefront of efforts to develop a Phobos mission. Likewise, authors Dr. Britt, from the University of Central Florida, and Dr. Pieters, from Brown University, have partnered with APL and JPL in Phobos/Deimos mission proposals.
APL scientists are not the only ones interested in Phobos or Deimos. The Jet Propulsion Laboratory, Ames Research Center and the SETI Institute have also proposed several missions to the small moons. Every NASA center has been involved at some level.
But the only mission to actually get off the ground is the Russian Space Agency’s Phobos-GRUNT[ref]. The Russian mission was launched November 9, 2011, and two months later took a bath in the Pacific Ocean. The propulsion system failed to execute the burns necessary to escape the Earth’s gravity and instead, its orbit decayed despite weeks of attempts to activate the spacecraft. But that’s a whole other story.
“The Value of a Phobos Sample Return” first discusses the origins of the moons of Mars. There is no certainty. There is a strong consensus that Earth’s Moon was born from the collision of a Mars-sized object with Earth not long after Earth’s formation. This is just one possibility for the Martian moons. Murchie explains that the impacts that created the large basins and craters on Mars could have spawned Phobos and Deimos: ejecta that achieved orbit, formed a ring and then coalesced into the small bodies. Alternative theories claim that the moons were captured by Mars from either the inner or outer solar system. Or they could have co-accreted with Mars from the Solar Nebula. Murchie and the co-authors describe the difficulties and implications of each scenario. For example, if captured by Mars, then it is difficult to explain how their orbits came to be “near-circular and near-equatorial with synchronous rotational periods.”
To answer the question of origins, the paper turns to the questions of their nature. Murchie explains that the limited compositional knowledge leaves several possibilities for their origins. They seem like D-type asteroids of the outer asteroid belt. However, the moons of Mars are very dry, void of water, at least on their surfaces as the paper discusses in detail. The flybys of Phobos and Deimos by NASA and ESA spacecraft are simply insufficient for drawing any clear picture of their composition or structure, let alone their origins, Murchie and co-authors explain.
If the moons were captured then they have compositions different from Mars; however if they accreted with or from Mars, then they share similar compositions with the early Mars when forming, or from Martian crustal material, respectively.
The paper describes in some detail the problem that billions of years of Martian dust accumulation presents. Every time Mars has been hit by a large asteroid, a cloud of debris is launched into space. Some falls back to the planet but much ends up in orbit. Each time, some of the debris collided with Phobos and Deimos; Murchie uses the term “Witness plate” to describe what the two moons are to Mars. There is an accumulation of Martian material and also material from the impactors covering the surfaces of the moons. Flyby images of Phobos show a reddish surface similar to Mars, and numerous tracks along the surface as if passing objects struck, plowed or rolled along. However, the reddish hue could be weathering from Solar flux over billions of years.
The paper continues with questions of the composition and how rendezvous missions could go further to understanding the moons makeup and origins, however, it is sample return that would deliver, the pay dirt. Despite how well NASA and ESA engineers have worked to shrink and lighten the instruments that fly, orbit, and land on Mars, returning a sample of Phobos to labs on Earth would permit far more detailed analysis.
Science Fiction writers and mission designers have imagined Phobos, in particular, as a starting point for the human exploration and colonization of Mars. A notable contemporary work is “Red Mars” by Kim Stanley Robinson; however, the story line is dated due to the retirement of the Space Shuttle and the external tanks Robinson clustered to form the colonization vessel. While this paper by Murchie et al. is purely scientific, fiction writers have used the understanding that Phobos is far easier to reach from Earth than is the surface of Mars (see Delta-V chart below).
Phobos, orbiting at 9,400 kilometers (5,840 miles), and Deimos, at 23,500 km (14,600 miles), above Mars avoids the need for the 7-odd minutes of EDL terror – Entry, Descent, and Landing — and pulling oneself out of the Martian gravity well to return to Earth. Furthermore, there is the interest in using Phobos as a material resource – water, material for rocket fuel or building materials. “The Value of a Phobos Sample Return” discusses the potential of Phobos as a resource for space travelers – “In Situ Resource Utilization” (ISRU), in the context of its composition, how the solar flux may have purged the moons of water or how Martian impact debris covers materials of greater interest and value to explorers.
With so many questions and interests, what missions have been proposed and explored? The Murchie paper describes a half dozen missions but there are several others that have been conceived and proposed to some level over several decades.
At present, there is at least one mission actively pursuing funds. The SETI and Ames proposed “Phobos and Deimos & Mars Environment” (PADME) mission led by Dr. Pascal Lee is competing for Discovery program funding. Such projects must limit cost to $425 million or less and be capable of launching in less than 3 years. They are proposing a launch date of 2018 on a SpaceX Falcon 9. The PADME mission design would reuse Ames LADEE hardware and expertise, however, it does not go so far as what Murchie and co-authors argue – returning a sample from Phobos. PADME would maintain in a synchronized orbit with Phobos and then Deimos foe repeated flybys. The mission is likely to cost in the range of $300 million. Stardust, a relevant mission due to its sample return capsule, launched in 1999 and had costs which likely reached a similar level by end of mission in 2012.
The Russian Space Agency is attempting to gain funding for Phobos-Grunt 2 but possible launch dates continue to be moved back – 2020, 2022, and now possibly 2024.
Additionally, each of this papers’ authors has mission proposals described. Dr. Pieters, JPL, and Lockheed-Martin proposed the Aladdin mission; Dr. Britt at APL, also with Lockheed-Martin, proposed the mission Gulliver; both would re-use the Stardust sample-return capsule (photo, above). Dr. Murchie also describes his APL/JPL mission concept called MERLIN (Mars–Moon Exploration, Reconnaissance and Landed Investigation).
Phobos and Deimos are the last two of what one would call major objects of the inner Solar System that have not had dedicated missions of exploration. Several bodies of the Asteroid Belt have been targeted with flybys and Dawn is nearing its second target, the largest of the Asteroids, Ceres.
So sooner rather than later, a spacecraft from some nation (not necessarily the United States) will target the moons of Mars. Targeted Phobos/Deimos missions are also likely to include both flyby missions and one or more sample-return missions. A US-led mission with sample-return in the Discovery program will be strained to meet both criteria – $425 million cost cap and 3 year development period.
Those utilizing the Lockheed-Martin (LM) Stardust design have a proven return capsule and spacecraft buses (structure, mechanisms and avionics) for re-use for cost and time savings. This includes five generations of the LM flight software that holds an incredible legacy of mission successes starting with Mars Odyssey/Genesis/Spitzer to now Maven.
All three proposals by this paper’s authors could be re-vamped and proposed again and compete against each other. All three could use Lockheed-Martin past designs. Cooperation in writing this paper may be an indicator that they will join forces, combine concepts, and share investigator positions on a single NASA-led project. The struggle for federal dollars remains a tough, tight battle and with the human spaceflight program struggling to gain a new footing after Space Shuttle, dollars for inter-planetary missions are likely to remain very competitive. However, it appears a Phobos-Deimos mission is likely within the next ten years.