rosseta.jpg
Photograph: ESA/ATG medialab

It's a curtain call of the spectacular kind: On September 30, the European Space Agency's (ESA) historic space probe Rosetta is to land gently on a comet 720 million kilometres away, taking some final pictures and measurements before going silent.

The landing of the probe comes more than a dozen years after it was launched into space  and two years after the probe dropped Philae, a lander filled with laboratory instruments, onto the comet - 67P/Churyumov–Gerasimenko - the first-ever landing by a man-made probe on a comet.

"We have never had Rosetta so close to Churi as this," says ESA flight director Paolo Ferri at the agency's satellite control centre in Darmstadt, using the shortened nickname for the comet discovered by Russian astronomers Klim Churyumov and Svetlana Gerasimenko in 1969. "We will be trying to take measurements and pictures right up to the final seconds."

If all goes to plan, the Rosetta will be landing at 1140 GMT on September 30, bringing an end to the 12-year mission. "When the space probe touches the surface of Churi, it will shut itself down," Ferri said. "We won't hear from it ever again."

The landing is to be extremely slow, slower than at walking speed.

"We are going to try to make the touchdown as gentle as possible," he added. The target area of the comet that measures some 4 kilometres long by 3.5 kilometres wide and 3.5 kilometres thick - some people liken its shape to a rubber duck - is to be at the "head" of the rocky mass.

The spot is to be next to a 130-metre-wide basin. ESA engineers believe the Rosetta will touch down 1-2 kilometres from the lander Philae.

The end of a mission is a time for taking stock, and scientists say that the secrets of Churi that were unveiled were of enormous significance.

Comets are thought to contain the oldest, largely unchanged, matter from the time when our solar system was formed some 4.6 billion years ago.

Altogether, Rosetta and Philae carried around 20 instruments to give Churi a close-up examination.

The Rosetta mission, costing some 1.3 billion euros (1.5 billion dollars) is one of the most ambitious projects undertaken by ESA.

The probe was launched March 2, 2004, from the European launching facility in Kourou, then spent years in an elliptical journey of several billion kilometres before finally catching up with the comet.

During its journey, the probe's systems were shut down in order to save up the energy needed for the final approach.

History was made November 12, 2014, when Philae was detached from the Rosetta and landed on the comet.

"This day is a historic one," proclaimed then-ESA general director Jean-Jacques Dordain of the first-ever landing on an asteroid.

Asked about his most special memories of the Rosetta mission, Ferri talks about the discoveries made.

"For me, the most spectacular result was a very early one, soon after the (Philae) landing. Namely, that the water on the comet had anything at all to do with the water here on Earth."

Nicolas Altobelli, ESA's expert for robotic exploration, noted that "never before could gas and dust be measured to close to a comet as we did with Rosetta."

He also cited the photographs sent back to Earth. "The pictures that Rosetta had already made of Churi in July 2014 were an absolute novelty. We recognized the comet core and its outlines. The similarity with a duck was there."

Stephan Ulamec, of the German space centre DLR and the project leader for the lander Philae, saw things similarly, stressing the camera system on board.

"The main findings from Philae were gained through the high-resolution photos taken by the Rolis and Civa cameras, revealing for the first time how a comet surface looks from right up close."

There were suggestions that Rosetta could be kept going, its systems shut down to save energy, to make yet another rendezvous with the comet and take further measurements, but Ferri dismissed the idea.

"Such a hibernation would last nearly four years," he said. But the decisive factor against prolonging the mission is that the Rosetta could not really do all that much more work.

The probe still has fuel for perhaps another six months. "It wouldn't be worth the risk," Ferri said.

Related stories

Latest news

SpaceX plans to fly two passengers around moon, NASA involved

SpaceX is planning to fly two private citizens around the moon next year, the first manned trip to the Earth's only natural satellite in more than four decades, the private company said Monday.

Key congressman has 'no evidence' of Trump contacts with Russia

The chairman of the US House of Representatives' Intelligence Committee said he is not aware of any evidence of improper contacts between Russian officials and Donald Trump's presidential campaign.

Gambia's new President Barrow fires army chief

Gambia's new President Adama Barrow has sacked army chief Ousman Badjie, replacing him with a presidential military aide.

Star investor Buffett takes a bigger bite of Apple, doubling shares

Stock market guru Warren Buffett on Monday revealed that his investment firm Berkshire Hathaway doubled its share of iPhone producer Apple stocks last month.

Minister: Erdogan not welcome in Austria for referendum campaign

Turkish President Recep Tayyip Erdogan should not come to Austria to campaign to Turkish citizens living there ahead of a constitutional reform referendum in his country, Austrian Foreign Minister Sebastian Kurz said Monday.

Migrant group: Britain hits 'new low' by deporting grandmother

Britain has hit a "new low" by deporting a grandmother from north-eastern England to Singapore, a migrants' rights group said on Monday.

Turkish judge remands German reporter in custody

A Turkish judge remanded German-Turkish journalist Deniz Yucel in custody Monday, according to newspaper Die Welt, sparking strong condemnation from the German government and rights organizations.

1.4 million people without water after deadly floods in Chile

More than 1.4 million people were without drinking water in the Chilean capital of Santiago on Monday following catastrophic flooding that left at least three people dead.

Serbia PM says no snap parliamentary election

Serbian Prime Minister Aleksandar Vucic said on Monday that an early parliamentary election would not be held simultaneously with a presidential vote, although the state leadership had announced such a possibility.  

Trump touts 'security budget' with 10-per-cent defence spending hike

US President Donald Trump says he will present a "public security and national security budget" that hikes military spending by 54 billion dollars or about 10 per cent.

National Front founder Jean-Marie Le Pen fined for Roma comments

The founder of France's far-right National Front, Jean-Marie Le Pen, had a 5,000-euro (5,300-dollar) fine for inciting racial hatred and discrimination confirmed on appeal on Monday.

Croatia-Montenegro relations example for region, says minister

After meeting Croatian Ambassador Veselko Grubisic in Podgorica on Monday, Montenegrin Defence Minister Predrag Boskovic said that relations between Croatia and Montenegro were very good and could serve as an example to other countries in the region.

Over 31,000 South Sudanese flee fighting and hunger to Sudan

Fleeing escalating fighting and famine in South Sudan, over 31,000 people have arrived in neighbouring Sudan so far this year, the UN refugee agency (UNHCR) said Monday.

SDP urges gov't to pull statement making radical turn in human rights

The opposition Social Democratic Party (SDP) on Monday called on the government to take a position on the Croatian foreign policy's turn in human rights, which it said was initiated by Foreign Minister Davor Ivo Stier, and to withdraw a Foreign Ministry statement on that sent to Brussels.

Police says photoshopped photo of Milanka Opacic motivated by hate

An investigation has proved that a photograph showing Parliament Deputy Speaker Milanka Opacic wearing a shirt with four Cyrillic letters "S" (standing for "only unity saves the Serb", a popular motto and slogan in Serbia and among Serb nationalists) is a photomontage and the police suspect that publishing and distributing the said photo has been motivated by hate and intolerance.

Finance Ministry says didn't analyse HEP's readiness for IPO

The Ministry of Finance on Monday announced that it had not analysed the justification or the readiness of power provider Hrvatska Elektroprivreda (HEP) for an initial public offering with regard to a possible acquisition of Hungarian energy company MOL's stake in Croatia's INA.

Berlin confirms murder of German hostage in the Philippines

Berlin confirmed on Monday the murder of a German hostage by the militant Islamist group Abu Sayyaf in the southern Philippines with Chancellor Angela Merkel condemning the killing as "barbaric" and "abominable".

Syrian refugees arrive in Italy with help from Christian groups

A group of 50 Syrian refugees, more than half of them children, landed in Italy early Monday, entering the country on humanitarian visas obtained with the help of a lay Catholic NGO, Protestant organizations and the Italian government.