Messenger spacecraft will crash on Mercury

After more than four years of orbiting Mercury, NASA’s Messenger spacecraft is about to end its mission with a bang. After more than 4,100 orbits around the closest planet to the sun, the satellite will crash into Mercury’s crater-pocked surface April 30.

NASA officials gave tribute in a briefing Thursday to the Messenger spacecraft, which was the first to orbit Mercury and which they say has fundamentally altered our understanding of this scorched little world.

“The spacecraft and the instruments have worked virtually flawlessly over those four years,” said James Green, director of NASA’s Planetary Science Division in Washington.

Launched in August 2004, the spacecraft has revealed many unexpected insights about that “first rock from the sun”: that, even within scorching distance, it has reserves of polar ice holding frozen water; that organic matter also coats protected areas near the poles; and that the tiny planet has a strong but lopsided magnetic field.

Mercury is among the least-studied planets in our solar system. Messenger was the first mission since the Mariner 10’s final flyby in 1975 to study this planet up close.

With so little previously known about Mercury, Messenger has opened up a trove of new information – and several surprises – in its three flybys and four years of orbiting the planet, said Sean Solomon, the mission’s principal investigator and director of Columbia University’s Lamont-Doherty Earth Observatory in New York.

Solomon put together a top-10 list of greatest discoveries made possible by Messenger. Among them: that the planet has an exceedingly thin atmosphere that changes with the seasons – and that sometimes trails behind the planet in a cometlike tail; that Mercury has shrunk by as much as 7 kilometers in radius; and that volcanism played a major role in shaping the planet’s surface. There are even different types of volcanic material on the surface that probably came from different reservoirs in the planet, he added.

“We have a record, if only we could read it – and we’re working on that now,” Solomon said.

The most important of the discoveries, he said, tops his list: that Mercury was surprisingly high in volatile elements, including potassium, sulfur, sodium and chlorine. Scientists had not expected this planet to be so high in these elements, which are thought to be among the first to escape a planet, particularly when it’s so close to the sun.

“It allows us to reject most of the ideas for how Mercury was assembled as a planet at the beginning of the history of the solar system,” Solomon said.

The most interesting, he said, was probably the second on his list – that the spacecraft was able to confirm the presence of polar water ice in permanently shadowed regions at the bottoms of craters.

“Those polar regions, I think, are calling out to people like Jim Green and saying, ‘Send us another spacecraft, we have more stories to tell,’” Solomon said, eliciting laughter from Green and others.

Green said that as a magnetosphere physicist, he was fascinated by Mercury’s lopsided magnetic field.

“I really enjoyed the magnetic field topologies . how does that really happen inside a planet?” Green said.

However, Messenger has only so much fuel, mission engineers pointed out.

“At the end of this month . we will lose our battle with solar gravity,” said Messenger’s project manager Helene Winters of the Johns Hopkins University Applied Physics Laboratory in Maryland. It will crash into the surface at about 8,700 mph, she added.

Messenger, loyal to the last, will send back data until minutes before its crash, said mission systems engineer Daniel O’Shaughnessy of the Johns Hopkins University Applied Physics Laboratory.

Data already sent back by the spacecraft will continue to be analyzed in the years to come, Solomon said.

Even in death, Messenger will prove useful. On impact, the spacecraft will make a roughly 52-foot-wide crater, a planetary scar whose characteristics may be useful for study by future spacecraft. More are coming: The joint ESA/JAXA mission BepiColombo is set to arrive at Mercury in 2024.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Local News

Trader Joe’s customers walk in and out of the store on Monday, Nov. 20, 2023 in Everett, Washington. (Olivia Vanni / The Herald)
New Trader Joe’s opens this week at Everett Mall

It’s a short move from a longtime location, essentially across the street, where parking was often an adventure.

Ian Bramel-Allen enters a guilty plea to second-degree murder during a plea and sentencing hearing on Wednesday, March 6, 2024, at Snohomish County Superior Court in Everett, Washington. (Ryan Berry / The Herald)
‘Deep remorse’: Man gets 17 years for friend’s fatal stabbing in Edmonds

Ian Bramel-Allen, 44, pleaded guilty Wednesday to second-degree murder for killing Bret Northcutt last year at a WinCo.

Firefighters respond to a small RV and a motorhome fire on Tuesday afternoon in Marysville. (Provided by Snohomish County Fire Distrct 22)
1 injured after RV fire, explosion near Marysville

The cause of the fire in the 11600 block of 81st Avenue NE had not been determined, fire officials said.

Ashton Dedmon appears in court during his sentencing hearing on Tuesday, March 5, 2024, at Snohomish County Superior Court in Everett, Washington. (Ryan Berry / The Herald)
Everett Navy sailor sentenced to 90 days for fatal hit and run

Ashton Dedmon crashed into Joshua Kollman and drove away. Dedmon, a petty officer on the USS Kidd, reported he had a panic attack.

A kindergarten student works on a computer at Emerson Elementary School on Wednesday, Feb. 28, 2024, in Everett, Washington. (Ryan Berry / The Herald)
‘¡Una erupción!’: Dual language programs expanding to 10 local schools

A new bill aims to support 10 new programs each year statewide. In Snohomish County, most follow a 90-10 model of Spanish and English.

Logo for news use featuring the Tulalip Indian Reservation in Snohomish County, Washington. 220118
Woman drives off cliff, dies on Tulalip Reservation

The woman fell 70 to 80 feet after driving off Priest Point Drive NW on Sunday afternoon.

Everett
Boy, 4, survives fall from Everett fourth-story apartment window

The child was being treated at Seattle Children’s. The city has a limited supply of window stops for low-income residents.

People head out to the water at low tide during an unseasonably warm day on Saturday, March 16, 2024, at Lighthouse Park in Mukilteo, Washington. (Ryan Berry / The Herald)
Everett shatters record high temperature by 11 degrees

On Saturday, it hit 73 degrees, breaking the previous record of 62 set in 2007.

Snohomish County Fire District #4 and Snohomish Regional Fire & Rescue respond to a motor vehicle collision for a car and pole. The driver was pronounced dead at the scene, near Triangle Bait & Tackle in Snohomish. (Snohomish County Sheriff’s Office)
Police: Troopers tried to stop driver before deadly crash in Snohomish

The man, 31, was driving at “a high rate of speed” when he crashed into a traffic light pole and died, investigators said.

Alan Dean, who is accused of the 1993 strangulation murder of 15-year-old Bothell girl Melissa Lee, appears in court during opening statements of his trial on Monday, March 18, 2024, at Snohomish County Superior Court in Everett, Washington. (Ryan Berry / The Herald)
31 years later, trial opens in Bothell teen’s brutal killing

In April 1993, Melissa Lee’s body was found below Edgewater Creek Bridge. It would take 27 years to arrest Alan Dean in her death.

Logo for news use featuring the municipality of Snohomish in Snohomish County, Washington. 220118
Man dies after crashing into pole in Snohomish

Just before 1 a.m., the driver crashed into a traffic light pole at the intersection of 2nd Street and Maple Avenue.

Bodies of two men recovered after falling into Eagle Falls near Index

Two men fell into the falls and did not resurface Saturday, authorities said. After a recovery effort, two bodies were found.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.