NASA’s Cassini spacecraft burns up in skies over Saturn

In this March 26, 1997 file photo, a technician checks the heat shield of the space probe Huygens in the cleanroom of Dornier Satellitensysteme GmbH in Ottobrunn, Germany, near Munich. The probe will be carried by NASA's Cassini orbiter and is designed to explore Saturn's moon Titan. (AP Photo/Uwe Lein)
Updated 15 September 2017
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NASA’s Cassini spacecraft burns up in skies over Saturn

CAPE CANAVERAL, Florida: NASA’s Cassini spacecraft disintegrated in the skies above Saturn early Friday in a final, fateful blaze of cosmic glory, following a remarkable journey of 20 years.
Confirmation of Cassini’s expected demise came about 7:55 a.m. EDT. That’s when radio signals from the spacecraft — its last scientific gifts to Earth — came to an abrupt halt. The radio waves went flat, and the spacecraft fell silent.
Cassini actually burned up like a meteor 83 minutes earlier as it dove through Saturn’s atmosphere, becoming one with the giant gas planet it set out in 1997 to explore. But it took that long for the news to reach Earth a billion miles away.
The only spacecraft to ever orbit Saturn, Cassini showed us the planet, its rings and moons up close in all their splendor. Perhaps most tantalizing, ocean worlds were unveiled on the moons Enceladus and Titan, which could possibly harbor life.
Dutiful to the end, the Cassini snapped its “last memento photos” Thursday and sampled Saturn’s atmosphere Friday morning as it made its final plunge.
Program manager Earl Maize made the official pronouncement:
“This has been an incredible mission, an incredible spacecraft and you’re all an incredible team,” Maize said. “I’ll call this the end of mission.”
Flight controllers wearing matching purple shirts stood and embraced and shook hands.
More than 1,500 people, many of them past and present team members, had gathered at California’s Jet Propulsion Laboratory for what was described as both a vigil and celebration. Even more congregated at nearby California Institute of Technology, which runs the lab for NASA.

NASA’s science mission director, Thomas Zurbuchen, made note of all the tissues inside JPL’s Mission Control, along with the customary lucky peanuts. Team members were clearly emotional, he said.
“These worlds that they found, we never knew were there, are changing how we think about life itself,” he said. “And so for me, that’s why it’s truly a civilization-scale mission, one that will stand out among other missions, anywhere.”
Project scientist Linda Spilker noted Cassini has been running “a marathon of scientific discovery” for 13 years at Saturn.
“So we’re here today to cheer as Cassini finishes that race,” she said.
The spacecraft tumbled out of control while plummeting at more than 76,000 mph (122,000 kph). Project officials invited ground telescopes to look for Cassini’s last-gasp flash, but weren’t hopeful it would be spotted against the vast backdrop of the solar system’s second biggest planet.
This Grand Finale, as NASA called it, came about as Cassini’s fuel tank started getting low after 13 years exploring the planet. Scientists wanted to prevent Cassini from crashing into Enceladus or Titan — and contaminating those pristine worlds. And so in April, Cassini was directed into the previously unexplored gap between Saturn’s cloud tops and the rings. Twenty-two times, Cassini entered the gap and came out again. The last time was last week.
The leader of Cassini’s imaging team, Carolyn Porco, a visiting scholar at the University of California, Berkeley, was so involved with the mission for so long that now, “I consider it the start of life, part two.”
Cassini departed Earth in 1997 and arrived at the sixth planet from our sun in 2004. The hitchhiking European Huygens landed on big moon Titan in 2005. Nothing from Earth has landed farther. Three other spacecraft previously flew past Saturn, but Cassini was the only one to actually circle the planet.
In all, Cassini collected more than 453,000 images and traveled 4.9 billion miles. It was an international endeavor, with 27 nations taking part. The final price tag was $3.9 billion.
European space officials joined their US colleagues to bid Cassini farewell.
“It’s a very historical moment,” said the Italian Space Agency’s president, Roberto Battiston.
There were lighthearted touches as well. During its broadcast NASA played a video clip of the Cassini Virtual Singers, spacecraft team members who belted out, “Tonight, tonight, we take the plunge tonight ...” to the music from “West Side Story.”
Scientists are already eager to go back and delve into the wet, wild worlds of Enceladus and Titan. Proposals are under consideration by NASA, but there’s nothing official yet. In the meantime, NASA plans sometime in the 2020s to send an orbiter and lander to Europa, a moon of Jupiter believed to have a global ocean that might be compatible for life.
“Yes, we really want to go back” to Saturn, Zurbuchen said. “It’s such a wonderful system, we don’t want to leave it alone.”


Greek researchers enlist EU satellite against Aegean sea litter

Greek university students gently deposits a wall-sized PVC frame on the surface before divers moor them at sea at a beach in the island of Lesbos on April 18, 2019. (AFP)
Updated 22 April 2019
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Greek researchers enlist EU satellite against Aegean sea litter

  • “All the targets were carried into the sea, the satellites passed by and we’re ready to fill out the first report”
  • Satellite data is provided free from the European Space Agency (ESA) and hours after the overpass targets should be detected from the Sentinel-2 satellite

LESBOS ISLAND, Greece: Knee-deep in water on a picture-postcard Lesbos island beach, a team of Greek university students gently deposits a wall-sized PVC frame on the surface before divers moor it at sea.
Holding in plastic bags and bottles, four of the 5 meter-by-5-meter (16 foot-by-16-foot) frames are part of an experiment to determine if seaborne litter can be detected with EU satellites and drones.
“This was the first big day,” says project supervisor Konstantinos Topuzelis, an assistant professor at the University of the Aegean department of Marine Sciences, said of the scene from last week.
“All the targets were carried into the sea, the satellites passed by and we’re ready to fill out the first report.”
The results of the experiment — “Satellite Testing and Drone Mapping for Marine Plastics on the Aegean Sea” — by the university’s Marine Remote Sensing Group will be presented at a European Space Agency symposium in Milan in May.
“Marine litter is a global problem that affects all the oceans of the world,” Topouzelis told AFP.
Millions of tons of plastic end up in the oceans, affecting marine wildlife all along the food chain.
“Modern techniques are necessary to detect and quantify marine plastics in seawater,” Topouzelis added, noting that space agencies have already been looking into how drones and satellites can help with the clean-up.
“The main advantage is that we are using existing tools,” which brings down costs and makes it easier to scale up, says Dimitris Papageorgiou, one of the 60 undergraduate and postgraduate students who worked on the experiment.
To prepare, the team gathered some 2,000 plastic bottles and lashed them to the frames. Other targets were crafted with plastic bags, as these are even harder to spot in the water and usually constitute the deadliest threat to Aegean marine life such as dolphins, turtles and seals.
In 2018, a first phase in the experiment was able to detect large targets of around 100 square meters from space.
This year’s experiment uses targets a quarter that size to test the smallest detectable area under various weather conditions.
“It was a crazy idea,” laughs Topouzelis.
“We knew that the European satellite system passes at regular intervals with a spatial resolution of 10 meters.”
In theory, then, the satellites should be able to detect the floating rafts of plastic the team pushed out to sea.
The University of the Aegean is working on the project with Universidad de Cadiz in Spain, CNR-Ismar in Italy and UK environmental consultants Argans Ltd.
Satellite data is provided free from the European Space Agency (ESA) and hours after the overpass targets should be detected from the Sentinel-2 satellite.
The project acts as a calibration and validation exercise on the detection capabilities of the satellites.
But even if relatively small patches of plastic garbage can be spotted from orbiting satellites, the problem of how to remove it from the sea remains.
Last year, a giant floating barrier five years in the making was launched off the coast of San Francisco, as part of a $20-million project to clean up a swirling island of rubbish between California and Hawaii.
But the slow speed of the solar-powered barrier prevents it from holding onto the plastic after it scoops it up.