Sweet desserts drive the search for disease-carrying mosquitoes

mamallena23.jpg

ZETA, (STRI.SI.EDU).- As researchers ask which disease-carrying mosquito species will rule Panama’s Azuero Penninsula (and perhaps the world), they discover culinary delights along the way.

Kelly Bennett sets out from Gamboa at 4:30am, crossing to the western side of the Panama Canal on the tall, cable-stayed Centennial bridge. The Smithsonian post-doctoral fellow is on a six-hour trek to the Azuero Peninsula to track two mosquito species capable of lethal viral diseases: malaria, yellow fever, dengue, Zika and Chikungunya.

At 7am she meets Smithsonian research associate Jose Loaiza, who is also a senior scientist at Panama’s government research institute, INDICASAT, and professor at the University of Panama, for breakfast at a tiny fonda in Penonome. His research assistant Jose Ricardo Rovira and master’s student Alejandro Almanza polish off plates of eggs, tortillas, carimañolas (yucca pastries stuffed with meat) and bistec picado (beef stew) as Kelly and Jose finalize plans for the day.

Kelly Bennett collects standing water. This water was too dirty to contain living larvae.

Mosquito species Aedes albopictus and Aedes aegypti both travel as eggs inside used and new tires. When water collects in the tires, the eggs hatch. Jose Loaiza collects water from a used tire as Alejandro Almanza and Jose Rovira watch.

Alejandro Almanza keeps track of the location of each of the houses in the study.

Kelly Bennett examines water from one of the buckets to see if mosquito larvae are present.

The so-called “Mosquito team” will make this trip down the Azuero penninsula every month for the next three years, hoping to better understand the ecology of two of the world’s most dangerous organisms: Aedes aegypti and Aedes albopictus. Aedes mosquitos carry a wide range of viral and parasitic diseases.

“More than 245 different mosquito species live in Panama,” says Kelly. The challenge for the team is to discover which Aedes mosquito species are at each site and whether they have the right environmental conditions to breed and to infect people.

Aedes aegypti, from sub-Saharan Africa, first colonized Europe from the early 18th to the late 20th century. Now one of the most widespread mosquito species in the world, Aedes aegypti is still restricted to the tropics because it can’t survive winter. But surfing on recent heatwaves, it has begun to move both north and south.

Like rats and cockroaches, Aedes aegypti’s success goes hand-in-hand with humans’ explosive population growth. It feeds mostly during the day in the shade and indoors and breeds in standing water in containers and trash around homes.

Researchers in Panama have kept track of Aedes aegypti for more than 100 years since the Cuban doctor, Carlos Finlay first suspected that it carried yellow fever, the disease that foiled the French attempt to build the Panama Canal, killing thousands of workers. Subsequent, draconian measures to eradicate yellow fever imposed by the U.S. military included fining owners of flower vases and baptismal fonts where immature larvae were found. They succeeded in eliminating yellow fever, but Aedes aegypti mosquitoes are back.

Now another species, the Asian Tiger mosquito, is actively expanding around the world. Aedes albopictus arrived in Panama only about 15 years ago, hitchhiking in shipments of new and used tires. Its population doubled in France in the last two years. It was reported in Jamaica for the first time only about a month ago.

Tiger mosquitos bite aggressively during the daytime and carry many of the same diseases carried by Aedes aegypti. The most worrisome difference between the two species is that Aedes albopictus can live where it is cold. It has the potential to pick up a virus in one part of the world and infect people on another continent.

Turning south off of the PanAmerican highway at Divisa, the team passes through La Arena and Chitre and on to Las Tablas, famous for its yearly Carnival blowout parades.

They stop to pick up Madeleine Ducasa, biology student at the University of Panama’s campus in Chitre, who waits with her father under the overhang of a roadside bus stop. Jose’s grant from Panama’s secretariat for science, technology and innovation (SENACYT) requires that he works with university students at all levels: “I was really lucky to find an undergraduate so passionate about the subject at a university on the Azuero.”

The forty-some miles (68.7 kilometers) from Las Tablas to Tonosí takes nearly an hour-and-a-half—winding up hills clad in brown, sun-baked pastures bordered by leafy, living fences. Dogs sleep in the road as if dead, sprinting to safety split seconds before becoming roadkill. At the very top of the ridge, four old men slap dominoes down on a plastic table in an open fonda overlooking the Pacific. Then the road winds down to the coast.

Tonosí purportedly takes its name from the indigenous big-man, Tocona, whose people succumbed to smallpox and were eventually replaced by outlaws attempting to distance themselves from the Spanish crown. These days about 2300 people call the town home. A frontier town, it’s a gateway for tourists hoping to see sea turtles nesting on the beaches at Caña Island and adventurers buying last-minute supplies for a trek into Cerro Hoya National Park.

“We love to work on the Azuero,” he adds. “People out here invite us in for coffee. In some other parts of the country, it’s not like that. Last week we set out mosquito traps at 15 houses. We ask people if we can put these small black buckets in their gardens. We try to spread out the traps so that we sample the whole area. To avoid sampling eggs from the same female, we pick houses that are about 100 yards (91 meters) apart.”

Jose parks the pickup in front of the first house. A woman gets up from the hammock on the porch to greet them. Jose and Kelly show her the larvae floating in the trap recovered from her yard. “The mosquitos lay their eggs on the popsicle stick we place in the bucket. They hatch. The smallest larval stage comes out. Then the larvae pass through four more stages, getting bigger each time. And eventually they become adults and fly away. These little larvae are Aedes,” says Jose.

Madeleine pours the contents of the bucket into a plastic bag labeled with the location and date. Kelly wipes the bucket with a white cotton swab, dropping it into the bag with the stick. It’s covered with pinprick-sized mosquito eggs. “We won’t know if they’re Aedes aegypti or Aedes albopictus until we take them back to the lab and they emerge as adults,” she explains.

Alejandro puts the bags in a plus-sized red cooler in the back of the truck. If the water gets too warm, the larvae die.” When he’s not helping with the mosquito project, he’s working on his master’s thesis, a study of a nocturnal biting fly species called Lutzomyia that transmits the disfiguring disease, leishmaniasis.

At the next house, they smell lentils cooking. The water from the bucket is full of squirming larvae.

“See that big larva there? That’s a predatory mosquito called Toxorhynchites. We have to get it out or it will eat all of the others.” Kelly siphons it off with her turkey baster and transfers it to a smaller bag.

Everyone troops back to the truck. “We try to pick the houses without fences in case we have to go back when no-one’s at home.” Kelly says she’s learned to deal with passive-aggressive dogs as she goes from house to house: “always face the dog. It’s when you turn and run that they bite.”

They walk around the corner of the next house, greeted by the broad smile of a woman vigorously grating coconut into an aluminum cooking pot. Her husband has been lining up cement blocks to enlarge their back patio, but he takes a break at her bidding, going inside to get a paper cup filled with miel de caña, molasses. She plans to cook the grated coconut with this syrup, adding some vanilla, to make cocadas.

“I’m getting tired of grating,” the woman says. “You can help me out by eating some of this coconut.” Madeleine holds the cup as everyone dips uneven pieces of coco into the golden-brown syrup, a welcome mid-morning snack.

The woman on the next porch worries because rain continues to pour down as the researchers troop into her back yard in search of the bucket. “It’s fine,” says Jose, “We’re biólogos. We’re resistant.”

The next house is surrounded by an edible garden of plantains, bananas, yucca and pumpkin vines with bright orange flowers. As we take a look at a plant we don’t recognize, the owner emerges from the back balcony to explain that it’s a home remedy for cleaning the blood. When we comment on the abundance of cherry tomatoes bunching on the vine along the side of the house, he goes back inside and emerges again with a pale-yellow plastic bag mounded with very cold, sweet bite-sized tomatoes, nothing like the hard, white-pulped tomatoes at the super market.

Kelly walks past a rose bush in a sawed-off yellow plastic cooking-oil container to sample standing water in another flower pot with her turkey baster—no larvae there.

The water in the mosquito trap looks suspiciously clear.

While the students empty the bucket into a bag, Senior Rovira, an experienced entomologist at INDICASAT wearing a Smithsonian polo shirt, walks around the property looking for trash and containers of standing water. A half-melted plastic bottle on the ground nearby contains hundreds of larvae, leading us to suspect that the landlady may have emptied out the trap, replacing the water because she was nervous that the team had something to do with the government’s health department, which still fines people who have standing water harboring mosquito larvae on their property.

Back in the truck, they continue down the road. “The next house had mangoes behind it, on this side of the street. No, not this one.”

“Is it ok if we take some mangos?” Jose asks the elderly couple on the porch after we empty the trap. “These are the best! They taste like pineapple!” Jose picks up a hard, green mango from the ground and sends it sailing up through the branches where it rips through several bunches of leaves, downing two dangling fruits, which bounce off in random directions, rolling among the cement paving stones of the garden.

Alejandro’s Google map stops working because there’s no internet signal on his phone in this part of town. As a backup he has photos of all the trap locations. The next house on the list is made from broad blue boards. The first blue house we come to has a pair of twin Chihuahuas with matching red collars on the porch. “I don’t remember those,” says Madeleine.

Then they see another blue house set back from the road, behind a cloud of woodsmoke from a smouldering fire in a big oil can. “That’s the one. I remember the lady.”

It’s 11:30 and everyone’s starting to get hungry, which leads to Jose to start telling a story: “We went to La Arena to a bakery on the way back home, and as we were ordering Alejandro said ‘Please give me 8 mamallenas.’ [Mamallenas are usually a very heavy bread pudding, full of cinnamon and raisins.] And I said ‘What? Eight is not the number you want. That’s too many.’ And Rovira said ‘Please, give me two mamallenas!’ What?! I said ‘Hold on you guys.’

And then Alejandro said ‘Try a mamallena.’ So I bought one. And I bought a chicha de maracuya—passion fruit juice.”

“The mamallena was GREAT! I bought three more. I couldn’t resist and I ate all three on the way back to Panama. And I remembered that Yamibel wanted one, so Rovira gave me one to give her. She called me later and said ‘I have NEVER had such a good mamallena!’ The next time we came out here, she gave us money to bring back 12 mamallenas.”

And so now, back at my office at INDICASAT, everyone asks me if we’re bringing mamallenas with us when we come back from our trips to the Azuero.

And I say ‘No…we’re bringing mosquitos!’”

The team heads to a restaurant for a late lunch. This afternoon they will move on to Cacao, a more rural community. On Saturday, they’ll work their way back up the peninsula.

“Pretty much every house we visited today had mosquitoes in the traps,” Jose sums up. Albopictus is a very aggressive newcomer. We think albopictus may be pushing aegypti out in rural areas. Aegypti likes urban places. Albopictus likes rural places. That’s mostly because Aegypti rests inside houses and Albopictus rests on the vegetation outside.”

“Yes, so what we really want to know is ‘who wins and who loses when these species meet?’,” Kelly continues. She has been analyzing the data they already collected in 2016 and 2017.

“What if you calculate the distance from a major highway?” Jose suggests.

Jose explains that these mosquitoes basically live with us all of the time, almost like domesticated animals. “The density of mosquitoes here is really high. People may not have a cat or a dog, but they have Aedes, and they probably don’t even realize it. In really rural areas Aedes albopictus has an advantage, whereas in the city we find almost all Aedes aegypti. It’s in little towns like Tonosí where this drama is playing out, where diseases either take hold or they don’t. The mosquitos are here. It’s in these settings where it is decided whether an epidemic gets started or not.”

Make your own mamallena, with or without gluten and sugar

Crumble day-old bread to make three cups. Add a cup-and-a-half of whole milk and/or evaporated milk. Add half a stick of margarine, three or four eggs, vanilla extract, at least a teaspoon of cinnamon, a big handful of raisins and a generous pinch of salt. Beat until the bread dissolves. Sprinkle a buttered cake pan with about half a cup of sugar and more raisins and then pour in the batter. Bake at medium heat until, when you stick a knife in, it comes out clean and the mamallena is golden brown. For people like Kelly who are gluten intolerant, you can make a gluten-free version by substituting 3 cups of mashed ripe plantains for the bread. You can leave the sugar out of this version, too.

https://stri.si.edu/story/mosquitoes-and-mamallenas

Add a comment

Tags: Swett desserts Mosquitoes

Copernicus Sentinel-5P ozone boosts daily forecasts

SATT.jpg

BARCELONA, (ESA).- Measurements of atmospheric ozone from the Copernicus Sentinel-5P satellite are now being used in daily forecasts of air quality.

Launched in October 2017, Copernicus Sentinel-5P – short for Sentinel-5 Precursor – is the first Copernicus satellite dedicated to monitoring our atmosphere. It is part of the fleet of Copernicus Sentinel missions that ESA develops for the European Union’s environmental monitoring programme.

The satellite carries an advanced multispectral imaging spectrometer called Tropomi. It detects the unique fingerprints of atmospheric gases in different parts of the electromagnetic spectrum to image a wide range of pollutants more accurately and at a higher spatial resolution than ever before.

And, sooner than expected, the Copernicus Atmosphere Monitoring Service (CAMS), which is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Union, is now including near-realtime Sentinel-5P ozone data in their daily analysis and forecast system.

Ozone is both good and bad, depending on where it is.

High up in the stratosphere, ozone is important because it protects life on Earth from the Sun’s harmful rays of ultraviolet radiation.

But lower down in the atmosphere, ozone is an air pollutant – the main ingredient of urban smog. It can cause breathing difficulties and also damage vegetation.

Before CAMS took the decision to start including the new Copernicus Sentinel-5P ozone data in their forecast system, the data had to be monitored and tested very carefully.

Since the data first became available in July, CAMS has been using them in research experiments parallel to their operational system. This allowed any teething problems to be solved.

Deemed good, the data were then included passively into the operational system so that differences between the forecast model and actual observations could be calculated.

CAMS senior scientist, Antje Inness, explained, “First, a lot of technical work is needed to include new data in the processing chain at ECMWF.

“Then the scientific work starts. We monitor the data passively and work with the team at the German Aerospace Centre, DLR, to solve any problems.

“Finally, the assimilation of the data can begin, and the data now influence the CAMS forecasts.”

Head of the service, Vincent-Henri Peuch, added, “Soon after Copernicus Sentinel-5P was launched in late 2017 we started monitoring the total column near-realtime ozone data in research experiments, and since July in our operational system.

“This has shown that the data are good quality and we are now starting to use them actively in our system.”

ESA’s mission manager for Copernicus Sentinel-5P, Claus Zehner, noted, “The uptake of these first data products into CAMS is a really important milestone – we couldn’t be happier.”

CAMS is also routinely monitoring the mission’s nitrogen dioxide and carbon monoxide data, which also look promising for uptake in the near future.

The Copernicus Sentinel-5P mission not only offers unprecedented accuracy, but also its 2600 km-wide swath allows the entire planet to be mapped every 24 hours.

All of the mission’s measurements of atmospheric gases and aerosols are ‘column data’, which means they cover the full depth of the atmosphere.

http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-5P/Copernicus_Sentinel-5P_ozone_boosts_daily_forecasts

Add a comment

BepiColombo now firing on all cylinders

bepic.jpg

BepiColombo, the joint ESA/JAXA spacecraft on a mission to Mercury, is now firing its thrusters for the first time in flight.

On Sunday, BepiColombo carried out the first successful manoeuver using two of its four electric propulsion thrusters. After more than a week of testing which saw each thruster individually and meticulously put through its paces, the intrepid explorer is now one step closer to reaching the innermost planet of the Solar System.

BepiColombo left Earth on 20 October 2018, and after the first few critical days in space and the initial weeks of in-orbit commissioning, its Mercury Transfer Module (MTM) is now revving up the high-tech ion thrusters.

The most powerful and high-performance electric propulsion system ever flown, these electric blue thrusters had not been tested in space until now.

It is these glowing power-packs that will propel the two science orbiters – the Mercury Planetary Orbiter and Mercury Magnetospheric Orbiter – on the seven-year cruise to the least explored planet of the inner Solar System.

“Electric propulsion technology is very novel and extremely delicate,” explains Elsa Montagnon, Spacecraft Operations Manager for BepiColombo.

“This means BepiColombo’s four thrusters had to be thoroughly checked following the launch, by slowly turning each on, one by one, and closely monitoring their functioning and effect on the spacecraft.”

Testing took place during a unique window, in which BepiColombo remained in continuous view of ground-based antennas and communications between the spacecraft and those controlling it could be constantly maintained.

This was the only chance to check in detail the functioning of this fundamental part of the spacecraft, as when routine firing begins in mid-December, the position of the spacecraft will mean its antennas will not be pointing at Earth, making it less visible to operators at mission control.

The first fire

On 20 November at 11:33 UTC (12:33 CET), the first of BepiColombo’s thrusters entered Thrust Mode with a force of 75 mN (millinewtons). With this BepiColombo was firing in space for the very first time.

Three hours later, the newly awakened thruster was really put through its paces as commands from mission control directed it to go full throttle, ramping up to 125mN – equivalent to holding an AAA battery at sea level.

This may not sound like much, but this thruster was now working at the maximum thrust planned to be used during the life of the mission.

Thrust mode was maintained for five hours before BepiColombo transitioned back to Normal Mode. The entire time, ESA’s Malargüe antenna in Argentina was in communication with the now glowing blue spacecraft – the colour of the plasma generated by the thruster as it burned through the xenon propellant.

These steps were then repeated for each of the other three thrusters over the next days, having only a tiny effect on BepiColombo’s overall trajectory.

The small effects that were observed allowed the Flight Dynamics team to assess the thruster performance in precise detail: analysis of the first two firings reveals that the spacecraft was performing within 2% of its expected value. Analysis of the last two firings is ongoing.

 

Add a comment

Postal Task Force Releases Report

United_States_Treasury_Building-777x437.jpg

WASHINGTON.- The U.S. Department of the Treasury today released the Task Force report on the United States Postal System.  The report, United States Postal System: A Sustainable Path Forward, provides a series of recommendations to overhaul the United States Postal Service’s (USPS) business model in order to return it to sustainability without shifting additional costs to taxpayers.

“The USPS is on an unsustainable financial path which poses significant financial risk to American taxpayers,” said Treasury Secretary Steven T. Mnuchin. “President Trump tasked us with conducting a thorough evaluation of the USPS, and today’s report contains achievable recommendations that fulfill the President’s goal of placing the USPS on a path to sustainability, while protecting taxpayers from undue financial burdens and providing them with necessary mail services.”

Between fiscal year (FY) 2007 and FY 2018, the USPS experienced net losses totaling $69 billion. The USPS is forecast to lose tens of billions of dollars over the next decade. The USPS’s business model—including its governance, product pricing, cost allocation, and labor practices—must be updated in light of its current operating realities.

On April 12, 2018, President Trump issued the https://www.whitehouse.gov/presidential-actions/executive-order-task-force-united-states-postal-system/&source=gmail&ust=1544110983699000&usg=AFQjCNH-2UayCtEFh8J74cc52q-7tV_lnQ">Executive Order on the Task Force on the United States Postal System. The Executive Order established a Task Force on the United States Postal System, chaired by the Secretary of the Treasury and including the Director of the Office of Management and Budget and the Director of the Office of Personnel Management.  The Task Force was directed to evaluate the operations and finances of the USPS and to develop recommendations for administrative and legislative reforms that will enable the USPS to create a sustainable business model.

 The Task Force’s recommendations include, but are not limited to:

  • Improving governance by strengthening the Board of Governors and developing enforcement mechanisms to ensure financial commitments and reforms are met;
  • Clearly defining the Universal Service Obligation by specifying what are “essential postal services,” or types of mail and packages for which a strong social or macroeconomic rationale exists for government protection;
  • Developing a new pricing model that removes price caps and charges market-based prices for both mail and package items that are not deemed “essential postal services”;
  • Modernizing the USPS’s cost standards and cost allocation methodology;
  • Pursuing cost-cutting strategies that will enable it to meet the changing realities of its business model;
  • Reforming USPS employee compensation in a manner consistent with proposed reforms to the broader federal workforce;
  • Restructuring retiree health benefit liabilities with a new actuarial calculation that is based on employees at or near retirement age;
  • Exploring new services that will allow the USPS to exact value from its existing assets and business lines, but that present no balance sheet risk.   
     

The Task Force’s full analysis and complete list of recommendations can be found in the full report.

https://home.treasury.gov/system/files/136/USPS_A_Sustainable_Path_Forward_report_12-04-2018.pdf&source=gmail&ust=1544110983699000&usg=AFQjCNGNEoFxPkQZHmNQexBb5C7zO-kZRA">View the Task Force report on the United States Postal System.

Add a comment
EIN.jpg

BARCELONA, (ESA).- Europe’s Galileo satellite navigation system – already serving users globally – has now provided a historic service to the physics community worldwide, enabling the most accurate measurement ever made of how shifts in gravity alter the passing of time, a key element of Einstein’s Theory of General Relativity.

Two European fundamental physics teams working in parallel have independently achieved about a fivefold improvement in measuring accuracy of the gravity-driven time dilation effect known as ‘gravitational redshift’.

The prestigious Physical Review Letters journal has just published the independent results obtained from both consortiums, gathered from more than a thousand days of data obtained from the pair of Galileo satellites in elongated orbits.

“It is hugely satisfying for ESA to see that our original expectation that such results might be theoretically possible have now been borne out in practical terms, providing the first reported improvement of the gravitational redshift test for more than 40 years,” comments Javier Ventura-Traveset, Head of ESA’s Galileo Navigation Science Office.

“These extraordinary results have been made possible thanks to the unique features of the Galileo satellites, notably the very high stabilities of their onboard atomic clocks, the accuracies attainable in their orbit determination and the presence of laser-retroreflectors, which allow for the performance of independent and very precise orbit measurements from the ground, key to disentangle clock and orbit errors.”

These parallel research activities, known as GREAT (Galileo gravitational Redshift Experiment with eccentric sATellites), were led respectively by the SYRTE Observatoire de Paris in France and Germany’s ZARM Center of Applied Space Technology and Microgravity, coordinated by ESA’s Galileo Navigation Science Office and supported through its Basic Activities.

Happy results from an unhappy accident

These findings are the happy outcome of an unhappy accident: back in 2014 Galileo satellites 5 and 6 were stranded in incorrect orbits by a malfunctioning Soyuz upper stage, blocking their use for navigation. ESA flight controllers moved into action, performing a daring salvage in space to raise the low points of the satellites’ orbits and make them more circular.

Once the satellites achieved views of the whole Earth disc their antennas could be locked on their homeworld and their navigation payloads could indeed be switched on. The satellites are today in use as part of Galileo search and rescue services while their integration as part of nominal Galileo operations is currently under final assessment by ESA and the European Commission.

However, their orbits remain elliptical, with each satellite climbing and falling some 8500 km twice per day. It was these regular shifts in height, and therefore gravity levels, which made the satellites so valuable to the research teams.

Reenacting Einstein’s prediction

Albert Einstein predicted a century ago that time would pass more slowly close to a massive object, a finding that has since been verified experimentally several times – most significantly in 1976 when a hydrogen maser atomic clock on the Gravity Probe-A suborbital rocket was launched 10 000 km into space, confirming Einstein’s prediction to within 140 parts per million.

In fact, atomic clocks aboard navigation satellites must already take into account the fact that they run faster up in orbit than down on the ground – amounting to a few tenths of a microsecond per day, which would result in navigation errors of around 10 km daily, if uncorrected.

The two teams relied upon the stable timekeeping of the passive hydrogen maser (PHM) clocks aboard each Galileo – stable to one second in three million years – and kept from drifting by the worldwide Galileo ground segment.

“The fact that the Galileo satellites carry passive hydrogen maser clocks, was essential for the attainable accuracy of these tests,” noted Sven Hermann at the University of Bremen’s ZARM Center of Applied Space Technology and Microgravity.

“While every Galileo satellite carries two rubidium and two hydrogen maser clocks, only one of them is the active transmission clock. During our period of observation, we focus then on the periods of time when the satellites were transmitting with PHM clocks and assess the quality of these precious data very carefully. Ongoing improvements in the processing and in particular in the modelling of the clocks, might lead to tightened results in the future.”

Refining the results

A key challenge over three years of work was to refine the gravitational redshift measurements by eliminating systematic effects such as clock error and orbital drift due to factors such as Earth’s equatorial bulge, the influence of Earth’s magnetic field, temperature variations and even the subtle but persistent push of sunlight itself, known as ‘solar radiation pressure’.

“Careful and conservative modelling and control of these systematic errors has been essential, with stabilities down to four picoseconds over the 13 hours orbital period of the satellites; this is four millionth of one millionth of a second,” Pacôme Delva of SYRTE Observatoire de Paris.

“This required the support of many experts, with notably the expertise of ESA thanks to their knowledge of the Galileo system.”

Precise satellite tracking was enabled by the International Laser Ranging Service, shining lasers up to the Galileos’ retro-reflectors for centimetre-scale orbital checks.

Major support was also received from the Navigation Support Office based at ESA's ESOC operations centre in Germany, whose experts generated the reference stable clock and orbit products for the two Galileo eccentric satellites and also determined the residual errors of the orbits after the laser measurements.

http://www.esa.int/Our_Activities/Navigation/Galileo_satellites_prove_Einstein_s_Relativity_Theory_to_highest_accuracy_yet

Add a comment