There are days when you just want to crawl under your desk and hide in the fetal position. I felt like that this morning. And indeed, I may feel this way for the rest of the week – or longer. Everywhere I turn, some giant challenge smacks me in the gut (ahem, global warming) and I'm supposed to bounce with glee like "NASA, NASA, rah rah roo!" all day long.
I'm sure you know what I mean. This weekend I walked past a busy café and saw single-use plastic trash spilling everywhere. You can see this in café after café, day after day, everywhere. It's a symptom of people paying lip service to caring for the environment, but being absolutely paralyzed. If the most we ask of ourselves is to buy more and more stuff and carry it a whole 2 feet to a trash bin, then how in the world are we going to tackle the big things?
The energy it takes to make honest, interesting and informative content for this climate website, the energy it takes to not let the daily deluge of Internet trolls and nasty comments get to me, all while facing the reality of GLOBAL WARMING, is exhausting.
I try to make a difference, to keep encouraging myself, to lift myself out of despair. We're supposed to keep our noses to the do-something-meaningful-with-your-life grindstone and keep chugging endlessly uphill, just like The Little Engine That Could, while repeating some mindless positive slogans of encouragement to keep our heads up.
I try to find a way to cope with these enormous problems without turning away, without downing a pint of ice cream, without watching the stupidest reality TV show I can find. For to be so disconnected from the world as to be capable of polluting it, is to be disconnected from life. And connection is the one thing I refuse to let go of.
True, maybe you really should crawl under your desk and your little engine should pull over to the side of the road for a break. But you're here, just like I am, pushing through because it's somehow better to stay connected even if it hurts.
I've sat in countless meetings here at NASA, where scientists and engineers fight to create complex flying machines that observe particles as tiny as a molecule from miles away, or hand build a one-of-a-kind experimental instrument from scratch, out of nothing but innovation and dreams. We thrive on the incomprehensibly difficult. We welcome problems, challenges, roadblocks, obstacles that are impossibly, mind-bogglingly large. That's why I'm here: To feed on frustration, difficulty and hindrance until I grow stronger and more ferocious.
I look forward to your comments.
Those of you who follow this blog know that, on top of launching satellites into space, NASA has a suite of Earth-observing instruments, a robust airborne program of instruments mounted on planes, and science ships.
Final frontier? I don't think so. Our catch phrase should be more like "Frontiers are us." We're all over the place.
Recently, Chris Mertens, a NASA scientist interested in galactic cosmic rays, shepherded a NASA balloon all the way to the top of Earth's atmosphere. The balloon, which stood a couple hundred feet tall and held 11 million cubic feet of helium, had a flight train attached to it with a payload of four science instruments and a parachute. He watched it lift off from NASA's Columbia Scientific Balloon Facility in Fort Sumner, New Mexico, and float away on a 24-hour research journey. "It was pretty surreal seeing it drift vertically away," he told me. "The apparatus looked big in the flight facility but looked so small as it was going up. It floated so gracefully, effortlessly."
Up, up and away
As the balloon lifted off, chief engineer Amanda Cutright could hear two sets of cheers, one at the location and a second over the delay at NASA's Langley Research Center where members of the team were watching a broadcast of the event. But she was "still holding her breath," waiting for the data to come in.
Mertens and Cutright, along with project manager Kevin Daugherty and the rest of the Radiation Dosimetry Experiment (RaD-X) team, had spent the past few weeks prepping the balloon and payload in the deserts of New Mexico and had been anxiously awaiting its launch. (Dosimetry is the science of determining radiation dosages received by the human body.) Daugherty told me they'd been waiting for the winds to stagnate in the upper atmosphere so they could fly over the southeastern U.S. for 24 hours without going into the populated areas of Mexico or Los Angeles.
Up in the air
The project actually began years ago when Mertens heard a pilot say, "I'm exposed to radiation and I don't know how much." See, someone on a one-way plane trip from Chicago to Germany on a normal day is exposed to approximately one chest X-ray's worth of radiation. Because commercial airline pilots and aircrew fly so frequently, they are actually radiation workers. So, with his background in cosmic radiation and space weather physics, Mertens knew he could develop a model to predict the radiation levels in Earth's upper atmosphere and answer that question. With this balloon flight, the RaD-X team expects to learn more about the amount of radiation flight crews receive on a daily, monthly or yearly basis and throughout their careers.
Up, up, up, up
About two hours after launch, the balloon reached the middle of the stratosphere, about 110-120 thousand feet up, right on the edge of space. That's about three times as high as commercial airplanes normally fly. From on-board cameras, "we could see the curvature of the Earth and watch the clouds recede," said Cutright. The team wanted to look at the incoming galactic cosmic rays and radiation from the sun above the region where the particles interact with the atmosphere and break up into smaller particles. "Earth's radiation environment is complex," Mertens explained. "Our magnetic field has a dynamic response to the solar wind and varies with latitude. At the polar regions, radiation exposure is maximum because the magnetic field lines are vertical. This means that during a solar storm, the incoming charged particles at the polar cap are parallel to the magnetic field lines, so there's no deflection by the magnetic field."
Yes, Earth's magnetic field is seriously rad.
Just past sunset, they purposely let enough helium out of the balloon to lower it to the 70-89 thousand foot range and have it float there overnight. All four dosimetry instruments collected data at both altitudes to feed into NAIRAS, an analytical model that simulates tissue and how radiation impacts it.
For the rest of the flight, the RaD-X team watched visuals from the onboard cameras, gathered near real-time data on their computers and tracked the balloon flight path from the control room.
"At one point late at night," said Cutright, "we were watching the Earth and we could see the moon. We could see a lightning storm over Oklahoma, all the way from the edge of Texas and New Mexico."
After sunrise, the team watched the parachute deploy so the payload could descend safely; from the camera view, they watched the Earth getting bigger and bigger. The payload was cut from the balloon and a large hole ripped on the side of the balloon so it could fall on its own off to the side. The balloon landed in a rancher's field and the Columbia Scientific Balloon Facility out of NASA Wallops recovered it.
Thank you for reading and for your comments.
P.S. 100 low-cost Cubes in Space experiments from 100 classrooms across the country were also on the flight. Some of their experiments included kernels of popcorn to see if they pop at altitude and seeds and electronics to find out how radiation affects them. Now that you know NASA helped students send kernels of popcorn to the edge of space, aren't you dying to find out if they popped or not? I am. I'll try my best to find out and post it here.
In the early 1960s, Mesa Road at NASA's Jet Propulsion Laboratory had not yet been built. Access to buildings on the mesa, like the High Gain Antenna Tower in this photo, was through the residential neighborhood north of JPL.
The antenna tower was built at the end of 1961, and was used by the Telecommunications Division in testing prototypes and various configurations of Deep Space Network antenna equipment. The platform was designed to reduce ground reflections from the sides and bottom of the adjacent canyon.
This morning when I told someone I’d interviewed NASA oceanographer Josh Willis for this blog, they replied, “Isn’t Josh Willis a climatologist?”
“Aha!” I said. “That’s a problem. Not knowing that Earth’s ocean is responsible for controlling the climate is major. Oceanographers are climatologists.”
I mean, look, the ocean covers 71 percent of the planet’s surface, and 71 percent is like, duh, a lot. The ocean, in fact, is so important that a better name for our planet would have been “Ocean” rather than “Earth” — even though our species spends most of its time on boring old land. #sorrynotsorry, geologists.
And you might not realize this because it’s so familiar, but water is crazy. It has this unusual property, called “high heat capacity,” that gives it the ability to hold a stable temperature. It resists heating and cooling. Water will absorb a lot of energy before it changes temperature even a little bit.
And this property of water, this high heat capacity, is what makes life on our planet possible. It’s also what controls and moderates our climate, which is why our ocean, more than our atmosphere, is responsible for creating a stable climate on Earth.
So this is the reason oceanographers are climatologists. It’s also part of the reason Willis chose to name his new science project Oceans Melting Greenland (OMG). He hopes that people everywhere will recognize the role Earth’s ocean plays in controlling the climate and to say to the world, “Hey! The ocean is eating away at the ice sheet! The ocean is playing a huge role in melting the glaciers; it's melting Greenland!”
Remember I just told you water absorbs a lot of energy before it heats up? Well, humans have added so much energy to the Earth system by burning fossil fuels that we have heated the ocean. And now that we’ve warmed it up, you guessed it: The water is in no hurry to change back, so we’re going to be stuck with this warmer water for a very long time. And, says Willis, “Since Greenland is one of the last two remaining ice sheets on the planet, its fate is intertwined with how much destruction we’re going to have with climate change.” If you just said “OMG,” you would be right.
But if you think scientists know everything there is to know about the ocean, you would be very wrong. Willis and his team want to find out more about the complicated geometry (the shape and depth of the seafloor) around Greenland to understand the interaction between the water and ice so that we can find out how fast the glaciers are melting.
This summer OMG used a ship, M/V Cape Race, to sail right up the narrow fjords on the continental shelf surrounding Greenland to the places where the 4- to 5-degree Atlantic Ocean water meets the bottoms of the frozen zero degree glaciers. The Cape Race used a multibeam echo sounder to map undersea canyons where the warm seawater comes in contact with and melts the glaciers. Willis followed the ship’s path via smartphone, sitting up in his PJs at two o’clock in the morning and uttering a variety of exclamations, including “OMG, turn left, left!”
Next year, the Cape Race will continue to make its way around Greenland, mapping the depth of the seafloor near the fjords, while Willis joins his team in the field flying on NASA’s G-III plane.
“OMG is a big picture project,” he told me. ”We want to see what’s happening in the ocean on the large scale and what’s happening to the ice sheet on the largest scales.”
In the spring, the NASA aircraft, with Willis aboard, will measure how much Greenland glaciers are thinning using the Glacier and Ice Surface Topography Interferometer (GLISTIN-A) instrument. They plan to deploy temperature and salinity probes in the summer. “In most of these places, there’s been no temperature and salinity data collected,” Willis said pausing, “ever.” Over the next five years, they will continue to monitor the ice sheet, asking, “When the water is this warm, how much ice melts?”
Willis knows “OMG” is a campy name for a NASA mission that makes light of a serious subject. “It’s easier to accept something as a reality when you can laugh at it, and accepting reality is a step towards making a change,” he said, explaining that if he was bummed out about climate change all the time, he would be stuck. “Humor makes it tolerable.”
Hopefully, when you find out about Oceans Melting Greenland, you’ll respond in the only way that’s appropriate: “OMG!”
Thank you for reading, sharing and commenting.
Eight years ago today, Dawn was gravitationally bound to a planet. It was conceived and built there by creatures curious and bold, with an insatiable yearning to reach out and know the cosmos. Under their guidance, it left Earth behind as its Delta rocket dispatched it on an ambitious mission to explore two of the last uncharted worlds in the inner solar system. As Earth continued circling the sun once a year, now having completed eight revolutions since its celestial ambassador departed, Dawn has accomplished a remarkable interplanetary journey. The adventurer spent most of its anniversaries powering its way through the solar system, using its advanced and uniquely capable ion propulsion system to reshape its orbit around the sun. On its way to the main asteroid belt, it sailed past Mars, taking some of the that red planet's orbital energy to boost its own solar orbit. On its fourth anniversary, the probe was locked in orbit around the giant protoplanet Vesta, the second most massive object between Mars and Jupiter. Dawn's pictures and other data showed it to be a complex, fascinating world, more closely related to the terrestrial planets (including one on which it began its mission and another from which it stole some energy) than to the much smaller asteroids.
Today, on the eighth anniversary of venturing into the cosmos, Dawn is once again doing what it does best. In the permanent gravitational embrace of dwarf planet Ceres, orbiting at an altitude of 915 miles (1,470 kilometers), Dawn is using its suite of sophisticated sensors to scrutinize this mysterious, alien orb. Ceres was the first dwarf planet ever sighted (and was called a planet for more than a generation after its discovery), but it had to wait more than two centuries before Earth accepted its celestial invitation. The only spacecraft ever to orbit two extraterrestrial destinations, this interplanetary spaceship arrived at Ceres in March to take up residence.
Although this is the final anniversary during its scheduled primary mission, Dawn will remain in orbit around its new home far, far into the future. Later this year it will spiral down to its fourth and final orbital altitude at about 230 miles (375 kilometers). Once there, it will record spectra of neutrons, gamma rays, and visible and infrared light, measure the distribution of mass inside Ceres, and take pictures. Then when it exhausts its supply of hydrazine next year, as it surely will, the mission will end. We have discussed before that despite the failure of two reaction wheels, devices previously considered indispensable for the expedition, the hardy ship has excellent prospects now for fulfilling and even exceeding its many goals in exploring Ceres.
Last month we described the plans for Dawn's penultimate mapping phase at the dwarf planet, and it is going very well. The probe is already more than halfway through this third orbital phase at Ceres, which is divided into six mapping cycles. Each 11-day cycle requires a dozen flights over the illuminated hemisphere to allow the camera to map the entire surface. Each map is made by looking at a different angle. Taken together then, they provide stereo views, so scientists gain perspectives that allow them to construct topographical maps. The camera's internal computer detected an unexpected condition in the third cycle of this phase, and that caused the loss of some of the pictures. But experienced mission planners had designed all of the major mapping phases (summarized here) with more observations than are needed to meet their objectives, so the deletion of those images was not significant. At this moment, the spacecraft is nearing the end of its fourth mapping cycle, making its tenth flight over the side of Ceres lit by the sun.
You can follow Dawn's progress by using your own interplanetary spaceship to snoop into its activities in orbit around the distant world, by tapping into the radio signals beamed back and forth across the solar system between Dawn and the giant antennas of NASA's Deep Space Network, or by checking the frequent mission status reports.
You also can see the marvelous sights by visiting the Ceres image gallery. Among the most captivating is Occator crater (see the picture below). As the spacecraft has produced ever finer pictures this year, starting with its distant observations in January, the light reflecting from the interior of this crater has dazzled us. The latest pictures show 260 times as much detail. Dawn has transformed what was so recently just a bright spot into a complex and beautiful gleaming landscape. Last month we asked what these mesmerizing features would reveal when photographed from this the present altitude, and now we know.
Scientists are continuing to analyze Dawn's pictures and other data not only from Occator but all of Ceres to learn more about the nature of this exotic relict from the dawn of the solar system. Many deep questions are unanswered and remain mystifying, but of one point there can be no doubt: the scenery is beautiful. Even now, the photos speak for themselves, displaying wondrous sights on a world shaped both by its own complex internal geological processes as well as by external forces from more than 4.5 billion years in the rough and tumble main asteroid belt.
Because the pictures speak for themselves, your correspondent will speak for the mission. So now, as every Sep. 27, let's take a broader look at Dawn's deep-space trek. For those who would like to track the probe’s progress in the same terms used on past anniversaries, we present here the eighth annual summary, reusing text from previous years with updates where appropriate. Readers who wish to reflect upon Dawn's ambitious journey may find it helpful to compare this material with the logs from its first, second, third, fourth, fifth, sixth and seventh anniversaries.
In its eight years of interplanetary travels, the spacecraft has thrust for a total of 1,976 days, or 68 percent of the time (and about 0.000000039 percent of the time since the Big Bang). While for most spacecraft, firing a thruster to change course is a special event, it is Dawn’s wont. All this thrusting has cost the craft only 873 pounds (396 kilograms) of its supply of xenon propellant, which was 937 pounds (425 kilograms) on Sep. 27, 2007. The spacecraft has used 66 of the 71 gallons (252 of the 270 liters) of xenon it carried when it rode its rocket from Earth into space.
The thrusting since then has achieved the equivalent of accelerating the probe by 24,400 mph (39,200 kilometers per hour). As previous logs have described (see here for one of the more extensive discussions), because of the principles of motion for orbital flight, whether around the sun or any other gravitating body, Dawn is not actually traveling this much faster than when it launched. But the effective change in speed remains a useful measure of the effect of any spacecraft’s propulsive work. Having accomplished 98 percent of the thrust time planned for its entire mission, Dawn has far exceeded the velocity change achieved by any other spacecraft under its own power. (For a comparison with probes that enter orbit around Mars, refer to this earlier log.) The principal ion thrusting that remains is to maneuver from the present orbit to the final one from late October to mid-December.
Since launch, our readers who have remained on or near Earth have completed eight revolutions around the sun, covering 50.3 AU (4.7 billion miles, or 7.5 billion kilometers). Orbiting farther from the sun, and thus moving at a more leisurely pace, Dawn has traveled 35.0 AU (3.3 billion miles, or 5.2 billion kilometers). As it climbed away from the sun, up the solar system hill, to match its orbit to that of Vesta, it continued to slow down to Vesta’s speed. It had to go even slower to perform its graceful rendezvous with Ceres. In the eight years since Dawn began its voyage, Vesta has traveled only 32.7 AU (3.0 billion miles, or 4.9 billion kilometers), and the even more sedate Ceres has gone 26.8 AU (2.5 billion miles, or 4.0 billion kilometers). (To develop a feeling for the relative speeds, you might reread this paragraph while paying attention to only one set of units, whether you choose AU, miles, or kilometers. Ignore the other two scales so you can focus on the differences in distance among Earth, Dawn, Vesta and Ceres over the eight years. You will see that as the strength of the sun's gravitational grip weakens at greater distance, the corresponding orbital speed decreases.)
Another way to investigate the progress of the mission is to chart how Dawn’s orbit around the sun has changed. This discussion will culminate with a few more numbers than we usually include, and readers who prefer not to indulge may skip this material, leaving that much more for the grateful Numerivores. (If you prefer not to skip it, click here.) In order to make the table below comprehensible (and to fulfill our commitment of environmental responsibility), we recycle some more text here on the nature of orbits.
Orbits are ellipses (like flattened circles, or ovals in which the ends are of equal size). So as members of the solar system family (including Earth, Vesta, Ceres and Dawn) follow their paths around the sun, they sometimes move closer and sometimes move farther from it.
In addition to orbits being characterized by shape, or equivalently by the amount of flattening (that is, the deviation from being a perfect circle), and by size, they may be described in part by how they are oriented in space. Using the bias of terrestrial astronomers, the plane of Earth’s orbit around the sun (known as the ecliptic) is a good reference. Other planets and interplanetary spacecraft may travel in orbits that are tipped at some angle to that. The angle between the ecliptic and the plane of another body’s orbit around the sun is the inclination of that orbit. Vesta and Ceres do not orbit the sun in the same plane that Earth does, and Dawn must match its orbit to that of its targets. (The major planets orbit closer to the ecliptic, and part of the arduousness of Dawn's journey has been changing the inclination of its orbit, an energetically expensive task.)
Now we can see how Dawn has done by considering the size and shape (together expressed by the minimum and maximum distances from the sun) and inclination of its orbit on each of its anniversaries. (Experts readily recognize that there is more to describing an orbit than these parameters. Our policy remains that we link to the experts’ websites when their readership extends to one more elliptical galaxy than ours does.)
The table below shows what the orbit would have been if the spacecraft had terminated ion thrusting on its anniversaries; the orbits of its destinations, Vesta and Ceres, are included for comparison. Of course, when Dawn was on the launch pad on Sep. 27, 2007, its orbit around the sun was exactly Earth’s orbit. After launch, it was in its own solar orbit.
from the Sun (AU)
from the Sun (AU)
|Dawn's orbit on Sep. 27, 2007 (before launch)||0.98||1.02||0.0°|
|Dawn's orbit on Sep. 27, 2007 (after launch)||1.00||1.62||0.6°|
|Dawn's orbit on Sep. 27, 2008||1.21||1.68||1.4°|
|Dawn's orbit on Sep. 27, 2009||1.42||1.87||6.2°|
|Dawn's orbit on Sep. 27, 2010||1.89||2.13||6.8°|
|Dawn's orbit on Sep. 27, 2011||2.15||2.57||7.1°|
|Dawn's orbit on Sep. 27, 2012||2.17||2.57||7.3°|
|Dawn's orbit on Sep. 27, 2013||2.44||2.98||8.7°|
|Dawn's orbit on Sep. 27, 2014||2.46||3.02||9.8°|
|Dawn's orbit on Sep. 27, 2015||2.56||2.98||10.6°|
For readers who are not overwhelmed by the number of numbers, investing the effort to study the table may help to demonstrate how Dawn has patiently transformed its orbit during the course of its mission. Note that four years ago, the spacecraft’s path around the sun was exactly the same as Vesta’s. Achieving that perfect match was, of course, the objective of the long flight that started in the same solar orbit as Earth, and that is how Dawn managed to slip into orbit around Vesta. While simply flying by it would have been far easier, matching orbits with Vesta required the exceptional capability of the ion propulsion system. Without that technology, NASA’s Discovery Program would not have been able to afford a mission to explore the massive protoplanet in such detail. But now, Dawn has gone even beyond that. Having discovered so many of Vesta's secrets, the stalwart adventurer left it behind in 2012. No other spacecraft has ever escaped from orbit around one distant solar system object to travel to and orbit still another extraterrestrial destination. Dawn devoted another 2.5 years to reshaping and tilting its orbit even more so that now it is identical to Ceres'. Once again, that was essential to the intricate celestial choreography in March, when the behemoth reached out with its gravity and tenderly took hold of the spacecraft. They have been performing an elegant pas de deux ever since.
Dawn takes great advantage of being able to orbit its two targets by performing extensive measurements that would not be feasible with a fleeting visit at high speed. As its detailed inspection of a strange and distant world continues, we can look forward to more intriguing perspectives and exciting insights into our solar system. On its eighth anniversary of setting sail on the cosmic seas for an extraordinary voyage, the faithful ship is steadily accumulating great treasures.
Dawn is 915 miles (1,470 kilometers) from Ceres. It is also 2.45 AU (228 million miles, or 367 million kilometers) from Earth, or 1,025 times as far as the moon and 2.45 times as far as the sun today. Radio signals, traveling at the universal limit of the speed of light, take 41 minutes to make the round trip.
Dr. Marc D. Rayman
4:34 a.m. PDT September 27, 2015
“The water is soooo warm!”
That sentence keeps popping out of Angelenos' mouths. It’s practically impossible to stick a toe into the California Pacific Ocean without making some sort of immediate involuntary exclamation regarding the water temperature. And the water has been unbelievably warm lately. The surf zone is full of swimmers frolicking in the waves. And even my cold-water averse puppy is now joyously prancing on his skinny little legs through the surf.
But along with the in-and-out, back-and-forth of the waves, my own moments of beach-ly delight also have an up-and-down quality. See, every time I stroll across the sand, I notice trash. Some pieces of trash are large items that people have obviously left on purpose, too neglectful to carry them away. Other pieces are small bits of plastic: a torn shred of wrapper, a crumb of rubber band that accidentally got away. I can’t help myself from noticing it. And I can’t help myself from picking it up, every piece I see, walking it over to a trash can, and throwing it in. When I see a piece of beach trash, nothing in me will allow me to walk past it. I can’t not pick it up.
A few days ago, as the sun was setting and most of the people had gone, I saw a seagull with a water bottle in its mouth. It reminded me of my puppy, who loves to chew a water bottle. He’ll grab it and run gleefully in circles until he drops and gets busy on the cap. If I don’t take it off him, he will start to swallow the chewed pieces. The gull was doing the same thing, playing with the bottle near the edge of the water, pecking instead of chewing, but otherwise in the same bouncy mood. I chased him down, took the water bottle off him and recycled it.
So I left the beach with mixed feelings. I’m just one person on one beach for one day. What about the rest of the beaches? What about the other days? Who will pick up the plastic there?
I come to this blog with similar mixed feelings. The warm waves feel wonderful, but I know it’s warm because of El Niño, the global climate event that starts on the eastern side of the Pacific Ocean all the way from California down to Peru. El Niño is complicated. *Will it bring much-needed rain to the parched southwestern region of the United States and relieve us from this ongoing drought? Will it be too much rain all at one time? Will it cause flooding and landslides?
Even now, the warmer waters on our side of the Pacific are causing many species that thrive in cooler waters to struggle while warmer water species are temporarily moving in. Sure, it’s interesting to SCUBA dive and see tropical fish, but the sea lions who depend on cooler waters are hating it big time.
Up-and-down, back-and-forth, in-and-out.
I figured you wouldn’t want to read yet another depressing piece about how much we’re trashing our planet. So, in searching for something less dismal, I went to talk with Bill Patzert and Josh Willis, unarguably the world’s leading experts on El Niño, to see what they had to say about our current El Niño conditions (other than the fact that they’re making a swim more pleasant and bringing lots of pink clouds to our Southern California sunsets).
As I walked in, the two NASA oceanographers were in the middle of a discussion about the impact of El Niño rains on the amount of ocean trash. “Oh perfect,” I thought. “So I’m going with a trash-themed blog. Game on, Oscar the Grouch, game on.”
When I told them about my inability to walk past trash at the beach, Patzert said, “Our beaches have been exceptionally clean for over a decade now because we haven’t had a strong El Niño. As soon as those rains come, any trash hibernating in our storm sewers or on our streets will get flushed into the L.A. River and onto SoCal beaches.”
Woohoo, trash!! Too bad Oscar isn’t a sea monster. He’d be elated.
Thank you for your comments.
*Some scientific info about El Niño: Most of the time, under normal ocean conditions, trade winds blow from the east side of the Pacific to the west side. These winds push surface water towards the Western Pacific near Asia and Australia where the warm water piles up. This Western Pacific Warm Pool contains some of the warmest ocean waters on the planet. Every decade or so, the trade winds soften and all that warm water that normally stays on the western side of the Pacific, sloshes back towards the east and we get a phenomenon known as El Niño. Since the Pacific Ocean takes up about half of planet Earth, it has the potential to affect global weather patterns. A strong El Niño can bring warm moist conditions to the West Coasts of the Americas, while leaving Australia and Southeast Asia unusually dry. So far, the 2015-2016 El Niño is shaping up to be an exceptionally strong one.
This April 1962 photo of Deep Space Station 12 (DSS-12) in Goldstone, California, was featured in Space Programs Summary 37-15, Volume 3–The Deep Space Instrumentation Facility. The 85-foot (26-meter) Echo antenna can be seen through the window of the control room, and three unidentified men are at the controls. The Echo site was named for its support of Project Echo, an experiment that transmitted voice communications coast to coast by bouncing signals off the surface of a passive balloon-type satellite. The antenna was moved six miles in June 1962 to the Venus site (DSS-13) and in 1979 it was extended to 34 meters in diameter.
The bimonthly Space Programs Summary, or SPS, is an excellent source of information about JPL missions and related research from February 1959 to October 1970. In 1970, the SPS series was replaced by the Technical Reports (32-1 to 32-1606) and other report series.
Dear Unhesidawntingly Enthusiastic Readers,
An ambitious explorer from Earth is gaining the best views ever of dwarf planet Ceres. More than two centuries after its discovery, this erstwhile planet is now being mapped in great detail by Dawn.
The spacecraft is engaged in some of the most intensive observations of its entire mission at Ceres, using its camera and other sensors to scrutinize the alien world with unprecedented clarity and completeness. At an average altitude of 915 miles (1,470 kilometers) and traveling at 400 mph (645 kilometers per hour), Dawn completes an orbit every 19 hours. The pioneer will be here for more than two months before descending to its final orbit.
The complex spiral maneuver down from the second mapping orbit at 2,700 miles (4,400 kilometers) went so well that Dawn arrived in this third mapping orbit on Aug. 13, which was slightly ahead of schedule. (Frequent progress of its descent, and reports on the ongoing work in the new orbit, are available here and on Twitter @NASA_Dawn.) It began this third mapping phase on schedule at 9:53:40 p.m. PDT on Aug. 17.
We had a detailed preview of the plans last year when Dawn was more than six thousand times farther from Ceres than it is today. (For reasons almost as old as Ceres itself, this phase is also known as the high altitude mapping orbit, or HAMO, although we have seen that it is the second lowest of the four mapping orbits.) Now let’s review what will happen, including a change mission planners have made since then.
The precious pictures and other data have just begun to arrive on Earth, and it is too soon to say anything about the latest findings, but stand by for stunning new discoveries. Actually, you could get pictures about as good as Dawn’s are now with a telescope 217 times the diameter of Hubble Space Telescope. An alternative is to build your own interplanetary spaceship, travel through the depths of space to the only dwarf planet in the inner solar system, and look out the window. Or go to the Ceres image gallery.
Dawn has already gained fabulous perspectives on this mysterious world from its first and second mapping orbits. Now at one third the altitude of the mapping campaign that completed in June, its view is three times as sharp. (Exploring the cosmos is so cool!) That also means each picture takes in a correspondingly smaller area, so more pictures are needed now to cover the entire vast and varied landscape. At this height, Dawn’s camera sees a square about 88 miles (140 kilometers) on a side, less than one percent of the more than one million square miles (nearly 2.8 million square kilometers). The orbital parameters were chosen carefully so that as Ceres rotates on its axis every nine hours (one Cerean day), Dawn will be able to photograph nearly all of the surface in a dozen orbital loops.
When Dawn explored the giant protoplanet Vesta from comparable orbits (HAMO1 in 2011 and HAMO2 in 2012), it pointed its scientific instruments at the illuminated ground whenever it was on the dayside. Every time its orbit took it over the nightside, it turned to point its main antenna at Earth to radio its findings to NASA’s Deep Space Network. As we explained last year, however, that is not the plan at Ceres, because of the failure of two of the ship’s reaction wheels. (By electrically changing the speed at which these gyroscope-like devices rotate, Dawn can turn or stabilize itself in the zero-gravity conditions of spaceflight.)
We discussed in January that the flight team has excogitated innovative methods to accomplish and even exceed the original mission objectives regardless of the condition of the wheels, even the two operable ones (which will not be used until the final mapping orbit). Dawn no longer relies on reaction wheels, although when it left Earth in 2007, they were deemed indispensable. The spacecraft’s resilience (which is a direct result of the team’s resourcefulness) is remarkable!
One of the many ingredients in the recipe for turning the potentially devastating loss of the wheels into a solid plan for success has been to rotate the spacecraft less frequently. Therefore, sometimes Dawn will wait patiently for half an orbit (almost 9.5 hours) as it flies above ground cloaked in the deep darkness of night, its instruments pointed at terrain they cannot detect. Other times, it will keep its antenna fixed on Earth without even glancing at the sunlit scenery below, because it can capture the views on other revolutions. This strategy conserves hydrazine, the conventional rocket propellant used by the small jets of the reaction control system in the absence of the wheels. It takes more time, but because Dawn is in orbit, time is not such a limited resource. It will take 12 passages over the illuminated hemisphere, each lasting nearly 9.5 hours, to bring the entirety of the landscape within view of its camera, but we will need a total of 14 full revolutions, or 11 days (29 Cerean days, for those of you using that calendar), to acquire and transmit all the data. The Dawn team calls this 11-day period “11 days,” or sometimes a “cycle.”
In quite a change from the days that there simply didn’t seem to be enough hydrazine onboard to accomplish all of the mission’s ambitious objectives, engineers and the spacecraft itself have collaborated to be so efficient with the precious molecules that they now have some to spare. Therefore, mission planners have recently decided to spend a few more in this mapping orbit. They have added extra turns to allow the robot to communicate with Earth during more of the transits over the nightside than they had previously budgeted. This means Dawn can send the contents of its computer memory to Earth more often and therefore have space to collect and store even more data than originally planned. An 11-day mapping cycle is going to be marvelously productive.
Full image and caption. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
But Dawn has goals still more ambitious than taking pictures and recording infrared and visible spectra of the lands passing underneath it. It will conduct six complete mapping cycles, each one looking at a slightly different angle. This will effectively yield stereo views, which when combined will make those flat images pop into full three dimensionality.
In its first mapping cycle, which is taking place now, the explorer aims its instruments straight down. For the second, it will keep the camera pointed a little bit back and to the left, making another full map but with a different perspective. For the third, it will look a little back and to the right. The fourth map will be viewing the scenery ahead and to the left. The fifth map will be of the terrain immediately ahead, and the sixth will be farther back than the third but not as far to the right.
In addition to the stereo pictures and the many spectra (which reveal the nature of the minerals as well as the surface temperature), Dawn will use the color filters in its camera to record the sights in visible and infrared wavelengths.
As always, mission planners schedule more observations than are needed, recognizing that glitches can occur on a complex and challenging expedition in the forbidding depths of space. So even if some data are not collected, the goals can still be accomplished.
The probe also will continue to acquire spectra both of neutrons and of gamma rays. It is unlikely to detect more than a whisper of neutrons from Ceres at this height, but the radiation coming from elsewhere in space now will serve as a useful calibration when it measures stronger nuclear emanations from one quarter the altitude starting in December, allowing scientists to inventory Ceres’ atomic constituents.
Precise measurements of Dawn’s radio signal will reveal more details of the dwarf planet’s gravitational field and hence the distribution of mass within. When the spacecraft is not aiming its main antenna at Earth, it will broadcast through one of its three auxiliary antennas, and the Deep Space Network will be listening (almost) continuously throughout the 84 orbits.
As at Vesta, Dawn’s polar orbits are oriented so that the craft always keeps the sun in view, never entering Ceres’ shadow, even when it is nighttime on the ground below. But its course will take the robot out of sight from Earth occasionally, and the behemoth of rock and ice will block the radio signal. Of course, Dawn is quite accustomed to operating in radio silence. It follows timed instructions (called sequences) that cover a full mapping cycle, so it does not require constant contact. And in budgeting how much data Dawn can collect and transmit, mission planners have accounted for the amount of time Ceres will eclipse its view of Earth.
Thanks to the uniquely efficient and exceptionally gentle thrust of the ion engines, as well as the flexibility inherent in being in orbit, Dawn operations generally can be more leisurely than those with conventional chemical propulsion or missions that only fly past their targets rather than stay for as long as needed. In that spirit, controllers had allowed the time in the spacecraft’s main computer to drift off, as there was no need to keep it particularly accurate. But recently the clock was off by so much that they decided to correct it, so before the mapping began, they adjusted it by a whopping 0.983 seconds, eliminating a large (but still tolerable) offset.
Many residents of Earth’s northern hemisphere are completing their leisurely summer vacations. As we saw in February, Dawn has measured the orientation of Ceres’ spin axis and found that it is tipped about four degrees (compared with Earth’s axial tilt of 23 degrees). The sun then never moves very far from the dwarf planet’s equator, so seasonal variations are mild. Nevertheless, northern hemisphere summer (southern hemisphere winter) began on Ceres on July 24. Because Ceres takes longer to revolve around the sun than Earth, seasons last much longer. The next equinox won’t occur until Nov. 13, 2016, so there is still plenty of time to plan a summer vacation.
Meanwhile, Dawn is working tirelessly to reveal the nature of this complex, intriguing world. Now seeing the exotic sights with a shaper focus than ever, the probe’s meticulous mapping will provide a wealth of new data that scientists will turn into knowledge. And everyone who has ever seen the night sky beckon, everyone who has heard the universe’s irresistible invitation, and everyone who has felt the overpowering drive for a bold journey far from Earth shares in the experience of this remarkable interplanetary adventure.
Dawn is 905 miles (1,456 kilometers) from Ceres. It is also 2.06 AU (191 million miles, or 308 million kilometers) from Earth, or 775 times as far as the moon and 2.03 times as far as the sun today. Radio signals, traveling at the universal limit of the speed of light, take 34 minutes to make the round trip.
Dr. Marc D. Rayman
5:00 p.m. PDT August 21, 2015
“How difficult is it going to be to switch from a fossil fuel economy to a renewable energy economy?” asked a gentleman from the audience. I paused and took a deep breath.
I was giving a lecture about climate change at a retirement community, and I’d been thinking about my own parents ever since I’d stepped through the front door earlier. Situated a couple hours north of Los Angeles, the “retirement village,” as they called it, was immaculate. It resembled a glamorous apartment hotel with Spanish architecture, wide foyers and grounds that were landscaped with drought-tolerant plants for the California climate. As I was escorted to the lecture hall, I noticed a few residents peacefully walking dogs.
I took a second breath and began my answer. “My parents would love it here.” A hundred puzzled faces looked up at me, wondering what this comment about my parents had to do with the global energy economy. “When I talk with them about moving out of their burdensome three-bedroom home, they tell me that if they could just snap their fingers and be here right now,” I said, waving my arm high while making a grand snapping gesture, “they’d simply do it immediately. But, they find the idea of the transition utterly unbearable. So they’re stuck. Heels dug in, entrenched, immobile, paralyzed.”
While I was talking, an image popped, unwelcome, into my mind’s eye. I saw my parents’ fine china, stacked in a dusty credenza, untouched for 47-plus years. “They don’t want to go through their belongings and make choices,” I said. “They’re afraid of the amount of hard work.”
At this point I needed to pull away from my own emotions and check in with the people sitting in front of me. “Does any of this make sense to you? Does it seem familiar?” I saw a hundred white-haired heads nod simultaneously. I heard a hundred mumbled “Uh huhs.” In all my years of public speaking, this was the first time I’d experienced an entire room of people in agreement.
One gentleman near the front said, “That was me before I came here.” Another said, “I have some friends exactly like that right now.”
It’s easy for me to imagine a time off into the future, eventually, someday, where people will look back on all the credenzas and all the coal-fired power plants and regard them with the same quaint fondness that we have for Dick Van Dyke’s chimney sweep character from “Mary Poppins”: charming relics of a bygone era.
What I worry about, on both personal and global levels, is that it might take a catastrophic upheaval before the transition to better, cleaner, more comfortable conditions occurs. And those kinds of catastrophic events could be painful, personally and globally. I said as much to the group of seniors at the retirement village, and this time I didn’t need to ask them if they understood me. I could see it in their eyes. And the same guy in the front said quietly, “Yeah, that was me before I came here.”
Thank you for reading, and thank you for your comments.
In December 1954, only a few months after becoming the director of JPL, Dr. William Pickering (in the light-colored suit) hosted a visit by Frank H. Higgins, assistant secretary of the Army, and several members of his military entourage. At that time, JPL was under contract to Army Ordnance to develop guided missiles. In this photo, the group is gathered in the control room of the 20-inch wind tunnel. Frank Goddard (in the dark suit), chief of the Supersonic Aerodynamics Division, assisted with the tour and Bud Schurmeier, manager of the Wind Tunnel Section, observed from the back of the room while technicians conducted a demonstration.