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Cassini to dive into Saturn at 113,000 kms per hour

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casssini aircraft to dive into sun
casssini aircraft to dive into sun (photo credit NASA)

When Cassini ends its 13-year tour of the Saturn system with an intentional plunge into the planet on Friday, the spacecraft’s speed will be approximately 113,000 kms per hour, NASA has said.

The final plunge will take place on the day side of Saturn, near local noon, with the spacecraft entering the atmosphere around 10 degrees north latitude, NASA said.

The spacecraft’s fateful dive is the final beat in the mission’s Grand Finale, 22 weekly dives, which began in late April, through the gap between Saturn and its rings.

No spacecraft has ever ventured so close to the planet before.

The mission’s final calculations predict loss of contact with the Cassini spacecraft will take place on Friday at 7:55 a.m. EDT.

Cassini will enter Saturn’s atmosphere approximately one minute earlier, at an altitude of about 1,915 kilometres above the planet’s estimated cloud tops.

When Cassini first begins to encounter Saturn’s atmosphere, the spacecraft’s attitude control thrusters will begin firing in short bursts to work against the thin gas and keep Cassini’s saucer-shaped high-gain antenna pointed at Earth to relay the mission’s precious final data.

As the atmosphere thickens, the thrusters will be forced to ramp up their activity, going from 10 per cent of their capacity to 100 per cent in the span of about a minute.

Once they are firing at full capacity, the thrusters can do no more to keep Cassini stably pointed, and the spacecraft will begin to tumble.

When the antenna points just a few fractions of a degree away from Earth, communications will be severed permanently, NASA said.

The predicted altitude for loss of signal is approximately 1,500 kilometres above Saturn’s cloud tops.

From that point, the spacecraft will begin to burn up like a meteor. Within about 30 seconds following loss of signal, the spacecraft will begin to come apart. Within a couple of minutes, all remnants of the spacecraft are expected to be completely consumed in the atmosphere of Saturn, NASA said.

Due to the travel time for radio signals from Saturn, which changes as both Earth and the ringed planet travel around the Sun, events currently take place there 83 minutes before they are observed on Earth.

This means that, although the spacecraft will begin to tumble and go out of communication at 6:31 a.m. EDT at Saturn, the signal from that event will not be received at Earth until 83 minutes later.

“The spacecraft’s final signal will be like an echo. It will radiate across the solar system for nearly an hour and a half after Cassini itself has gone,” said Earl Maize, Cassini project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California.

“Even though we’ll know that, at Saturn, Cassini has already met its fate, its mission isn’t truly over for us on Earth as long as we’re still receiving its signal,” Maize added.

Live mission commentary and video from Jet Propulsion Laboratory Mission Control will air on NASA TV and the agency’s website from 7 to 8:30 a.m. EDT (4.30 to 6 pm India time)on Friday.

Launched in 1997, Cassini arrived in orbit around Saturn in 2004 on a mission to study the giant planet, its rings, moons and magnetosphere.

 (IANS)

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UNSC unanimously votes resolution ordering ceasefire in Syria

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UNSC(File Photo)

United Nations, Feb 25: The ten elected non-permanent members (E10) of the UN Security Council pushed the five permanent members (P5) to reach a compromise and got an unanimous vote on a resolution ordering a ceasefire “without delay” in Syria to allow humanitarian aid to reach areas under siege.

After two days of delays and several postponements, Russia and the three western permanent members — Britain, France and the United States — agreed on Saturday, on the final version negotiated by Kuwait and Sweden with the backing of the P10.

Kuwait’s Permanent Representative Mansour Ayyad Al-Otaibi, who is the Council President for the month, said after the resolution passed that the unanimous vote was a “sign that the Security Council is united” and this could pave the way for finding a lasting political solution to the seven-year conflict.

Hoping to shame the permanent members locked in a standoff and push them to a compromise, all the the E10 representatives lined up together and held a news conference on Friday while the negotiations were on. “We want to show you the solidarity of the E10,” Al-Otaibi declared: “We are all united, we want the resolution to be adopted.”

The unrelenting push by Al-Otaibi and Sweden’s Permanent Representative Olof Skoog won praise from every one of the Council members. It was a rare instance of the E10 bending the P5, instead of the other way around.

Besides the nation-wide ceasefire, the resolution calls for the lifting of all sieges, facilitation of medical evacuations, and permitting convoys of the UN and its partners carrying humanitarian supplies free access.

However, the resolution made one notable exception to the ceasefire: It allowed continued action against the Islamic State, Al-Qaeda, A1-Nusra Front and other terrorist organisations.

The key point of contention that held up the resolution since it was formally introduced by Kuwait and Sweden on Wednesday was the timing of when the ceasefire should start. The US demanded it should be immediate, while Russia wanted lag before it went into effect and the threat of a Moscow veto hung over it.

The resolution now says it will come into force “without delay,” leaving an element of ambiguity subject to interpretations.

Speaking to reporters after the vote, Al-Otaibi said they debated about the timing during the negotiations all of Friday and into Saturday morning. “Without delay means” immediately, he said.

Russia’s Permanent Representative Vassily Nebenzia was non-commital about. He told reporters that the reason his country held out on the wording of the timing was that it was logistical issue and a “painful process on the ground.”

He added that another concern of Moscow was that resolution was not used as a pretext to launch an invasion of Syria.

With the drawn-out negotiations, Syria got three days to prepare for it.

Speaking in the Council after the vote, United States Permanent Representative Nikki Haley lashed out at Russia saying that during the time it held up the resolution to change a “few words and some commas,” mothers lost their children to bombing and shelling.

“The Syrian people should not have to die waiting for Russia to organise their instructions from Moscow, or to discuss it with the Syrians,” she added.

The action on the ceasefire was precipitated situation in East Ghouta, which UN Secretary-General Antonio Guterres has called “hell on Earth”. One of the few rebel-held territories, the Damascus suburb has been under a siege and bombed from the air by the Syrian government forces.

East Ghouta was specifically mentioned, along with several other areas, but the Kurdish city of Afrin was not. Intense fighting has been underway in the area between Turkey’s military and Kurdish militias backed by Syrian government forces.

Asked about it by reporters, Al-Otaiby said the ceasefire applied to all of Syria and to all forces operating there.

IANS

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Kabul seeks closure of Taliban’s Qatar office

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Taliban office in Qatar
Taliban office in Qatar (Photo- The Newyork Times)

Doha, Feb 24: Kabul has started discussions with the Qatari government to close the Taliban office in Doha as it has had “no positive consequence in terms of facilitating the peace talks with the group in Afghanistan”, a senior government official has said.

“There is no need to keep the office open”, said Mohammad Hanif Atmar, National Security Advisor to President Ashraf Ghani, in an interview with Middle East newspaper Asharq Al-Awsat earlier this week.

“The aim behind opening (Taliban’s) Qatar office was to start official peace negotiations with the terror group from the address, but so far no official negotiation from the office has been started with government. Even a single step has not been taken forward in the peace process through this office,” Qadir Shah, a spokesman for Atmar’s office said.

“It had no benefit for us even after seven years… It is better to close it,” Atmar said.

He also said that Kabul has so far witnessed no sign of “sincere” cooperation from Islamabad in counter-terrorism efforts.

The Taliban had earlier reached out to the US with an offer for talks and urged people to pressurize Washington to bring an end to the invasion of Afghanistan.

The Taliban had said that they preferred to resolve the conflict that began in 2001 through peaceful dialogue and warned that the use of force alone would complicate the problem in Afghanistan.

The group had called on the “American people and the peace-loving Congressmen” to pressurize US leadership to end the occupation of the Asian country, a precondition that Taliban has always maintained to begin any negotiation.

IANS

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Moon’s water may be widely distributed: Study

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Washington, Feb 24: A new analysis of data from India’s Chandrayaan-1 mission and NASA’s Lunar Reconnaissance Orbiter suggests that Moon’s water may be widely distributed across the surface, not confined to a particular region or type of terrain.

The water appears to be present day and night, though it was not necessarily easily accessible, according to the study published in the journal Nature Geoscience.

“We find that it doesn’t matter what time of day or which latitude we look at, the signal indicating water always seems to be present,” said Joshua Bandfield, a senior research scientist with the Space Science Institute in the US, and lead author of the new study.

“The presence of water doesn’t appear to depend on the composition of the surface, and the water sticks around,” Bandfield added.

The results contradict some earlier studies, which had suggested that more water was detected at the Moon’s polar latitudes and that the strength of the water signal waxes and wanes according to the lunar day (29.5 Earth days).

The findings could help researchers understand the origin of the Moon’s water and how easy it would be to use as a resource.

If the Moon has enough water, and if it is reasonably convenient to access, future explorers might be able to use it as drinking water or to convert it into hydrogen and oxygen for rocket fuel or oxygen to breathe.

The new finding of widespread water suggests that it may be present primarily as OH, a more reactive relative of H2O that is made of one oxygen atom and one hydrogen atom.

OH, also called hydroxyl, does not stay on its own for long, preferring to attack molecules or attach itself chemically to them. Hydroxyl would therefore have to be extracted from minerals in order to be used.

For the study, the researchers analysed data from the Moon Mineralogy Mapper spectrometer onboard the Chandrayaan-1 spacecraft.

They came up with a new way to incorporate important temperature information, creating a detailed model from measurements made by the Diviner instrument on NASA’s Lunar Reconnaissance Orbiter, or LRO.

The researchers are still discussing what the findings tell them about the source of the Moon’s water.

The results point toward OH and/or H2O being created by the solar wind hitting the lunar surface, though the team did not rule out that OH and/or H2O could come from the Moon itself, slowly released from deep inside minerals where it has been locked since the Moon was formed.

IANS

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