News / Science & Technology

NASA GRAIL Probes Begin Lunar Orbit

This undated artist rendering provided by NASA shows the twin Grail spacecraft mapping the lunar gravity field. The two probes are scheduled to enter orbit around the moon over New Year's weekend.
This undated artist rendering provided by NASA shows the twin Grail spacecraft mapping the lunar gravity field. The two probes are scheduled to enter orbit around the moon over New Year's weekend.

The U.S. space agency, NASA, has celebrated the new year with twin spacecraft circling the Moon on a mission to study its gravitational field and internal structure.

NASA launched the two unmanned Gravity Recovery and Interior Laboratory, or GRAIL, probes in September.  The first probe, GRAIL A, was placed into lunar orbit on Saturday, and the second, GRAIL B, followed on Sunday.

The orbiting GRAIL spacecraft are scheduled to spend about 90 days gathering data to create the first complete high-resolution map of the Moon’s curiously uneven gravitational field.  Scientists say they will use the new gravity data to find out what goes on beneath the lunar surface, “from crust to core.”

Mission principal researcher, Maria Zuber of the Massachusetts Institute of Technology, says the GRAIL project will, in her words, “rewrite the textbooks on the evolution of the Moon.”

NASA says it expects insights from the GRAIL mission will lead to a better understanding of how the Earth and the three other rocky planets (Mercury, Venus and Mars) in the inner solar system developed into the diverse worlds seen today.

NASA anticipates that GRAIL’s comprehensive map of the Moon’s gravitational field also will provide an important navigational tool for future lunar spacecraft. The space agency says it plans to plunge both GRAIL spacecraft into the lunar surface several weeks after the orbital mapping mission is complete.

The Moon orbits the Earth from an average distance of around 385,000 kilometers.  It has a diameter of nearly 3,500 kilometers.  By contrast, the Earth’s is 12,756 kilometers-wide.  Because the Moon is smaller and has less mass, the force of gravity on the lunar surface is only 17 percent of that on Earth.  That means the same object that weighs 100 kilograms on Earth will weigh only 17 kilograms on the Moon.

Astronomers believe the Moon formed 30 to 50 million years after the rest of our solar system first coalesced from leftover stellar dust and gas 4.6 billion years ago.  The dominant theory is that the Moon is made of debris that circled the still-molten Earth in the wake of a cataclysmic collision with a smaller Mars-sized protoplanet.

You May Like

Obama: I Will Do 'Everything I Can' to Close Guantanamo

US president says prison continues 'to inspire jihadists and extremists around the world' More

Sierra Leone Educates on Safe Ebola Burials

Also, country is improving at rapid response to isolated outbreaks, but health workers need to be even faster, officials say More

Religion Aside, Christmas Gains Popularity in Communist Vietnam

Increasingly wealthy Vietnamese embrace holiday due to its non-religious glamor, commercial appeal More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Decision on Cuba Underscores Divisions Among Miami Cubansi
X
Sharon Behn
December 19, 2014 9:34 PM
For decades, older, more conservative Cubans have been gathering at Café Versailles on the corner of Calle Ocho to eat Cuban food and talk politics. After hearing of President Barack Obama’s decision, a number of them gathered in front of the café with posters to protest. VOA's Sharon Behn reports on the situation.
Video

Video US Decision on Cuba Underscores Divisions Among Miami Cubans

For decades, older, more conservative Cubans have been gathering at Café Versailles on the corner of Calle Ocho to eat Cuban food and talk politics. After hearing of President Barack Obama’s decision, a number of them gathered in front of the café with posters to protest. VOA's Sharon Behn reports on the situation.
Video

Video Three Cities Bid for Future Obama Presidential Library

President Barack Obama still has two years left in his term in office, but the effort to establish his post-presidential library is already underway. The bid for the Obama Presidential Library is down to four locations in three states -- New York, Hawaii, and Illinois. As VOA’s Kane Farabaugh reports, each of them played an important part in the president’s life before he reached the White House.
Video

Video Cuba Deal is Major Victory for Pope’s Diplomatic Initiatives

Pope Francis played a key role in brokering the US-Cuba deal that was made public earlier this week. It is the most stunning success so far in a series of peacemaking efforts by the pontiff. VOA religion reporter Jerome Socolovsky has more.
Video

Video Fears of More Political Gridlock in 2015

2014 proved to be a difficult year politically for President Barack Obama and a very good year for the U.S. Republican Party. Republican gains in the November midterm elections gave them control of the Senate and House of Representatives for the next two years -- setting the stage for more confrontation and gridlock in the final two years of the Obama presidency. VOA National Correspondent Jim Malone has a preview from Washington.
Video

Video Sudan School Becomes Target of Aerial Attacks

The school dropout rate is at an all-time high in Sudan's South Kordofan state because many schools have been destroyed during the three-year civil war between the government and SPLA-N rebel forces. Adam Bailes visited Sudan's Nuba Mountains' region and reports many children are simply too scared to go to school
Video

Video VOA Reporter Tours Devastated Peshawar School

Islamist militants wearing military uniforms and strapped with explosives attacked a military run school Tuesday in the northwestern Pakistani city of Peshawar. At least 141 people were killed in the horrific attack, most of them young students. VOA reporter Ayaz Gul visited the devastated school and attended the funeral of the principal who courageously tried to save her students from the deadly attack.
Video

Video Nigerians Fleeing Boko Haram Languish in Camp Near Capital

In its five-year effort to impose Islamic law in northeastern Nigeria, the Boko Haram extremist group has killed thousands of people and forced hundreds of thousands to flee. Some of those who ran for their lives now live in squalor on the edges of the capital, Abuja. Chris Stein reports for VOA.
Video

Video Aceh Rebuilt Decade After Tsunami, But Scars Remain

On December 26, 2004 there was an earthquake in the Indian Ocean so powerful it caused the Earth’s axis to wobble a few centimeters. Onshore on the island of Sumatra, the resulting tsunami was devastating. A decade later, VOA Correspondent Steve Herman reports from Banda Aceh, Indonesia, where although there is little remaining evidence of the physical devastation, the psychological scars among survivors remain.

All About America

AppleAndroid