according to rubén salazar what was a chicano

Salazar's strong support for the Chicano movement as a Mexican-American distinguished him early on from other journalists in mainstream media. With a strong disparity of racial minorities in news organizations nationwide, Salazar felt it was his personal and professional responsibility to give necessary attention to the actions led by his fellow Chicanos in East Los Angeles. In February 1970, just six months prior to his death, Salazar made his support for the Chicano movement particularly clear when he authored an article in the Los Angeles Times, titled, "Who Is A Chicano? And What Is It the Chicanos Want?" In this piece, Salazar not only describes the evolving identity of Chicanos and the historic importance of the movement, but he details his frustration with the lack of Mexican-American representation among the elected representatives in the Los Angeles city council. Salazar writes, "Mexican-Americans, though large in numbers, are so politically impotent that in Los Angeles, where the country's largest single concentration of Spanish-speaking live, they have no one of their own on the City Council. This in a city politically sophisticated enough to have three Negro council-men."[6]

Ruben Salazar

Ruben Salazar (March 3, 1928 â€“ August 29, 1970)[1] was a reporter for the Los Angeles Times, the first Mexican-American journalist from mainstream media to cover the Chicano community.[2]

Salazar died during the National Chicano Moratorium March against the Vietnam War on August 29, 1970, in East Los Angeles, California. During the march, Salazar was struck by a tear-gas projectile fired by a Los Angeles County Sheriff's deputy. No criminal charge was filed, but Salazar's family reached an out-of-court financial settlement with the county.[2]

Born in Ciudad Juarez, Mexico, Salazar was brought to the United States with his family in 1929.  Salazar began his U.S. naturalization process on October 15, 1947, when he submitted his application for a certificate of arrival and preliminary form for a declaration of intention of citizenship.

After high school, he served in the U.S. Army for two years. Salazar attended the Texas Western College, graduating in 1954 with a degree in journalism. He obtained a job as an investigative journalist at the now-defunct El Paso Herald-Post; at one point he posed as a vagrant to get arrested while he investigated the poor treatment of prisoners in the El Paso jail. After his tenure at the Herald-Post, Salazar worked at several California newspapers, including the Santa Rosa Press Democrat.[2][3]

Salazar was a news reporter and columnist for the Los Angeles Times from 1959 to 1970.[4] During his career, Salazar became one of the most prominent figures within the Chicano movement. He served as a foreign correspondent in his early years at the Times, covering the 1965 United States occupation of the Dominican Republic, the Vietnam War, and the Tlatelolco massacre (the latter while serving as the Times' bureau chief in Mexico City).

When Salazar returned to the US in 1968, he focused on the Mexican-American community and the Chicano movement, writing about East Los Angeles, an area largely ignored by the media except for coverage of crimes. He became the first Chicano journalist to cover the ethnic group while working in a large general circulation publication. Many of his pieces were critical of the Los Angeles government's treatment of Chicanos, particularly after he came into conflict with police during the East L.A. walkouts.[2] While reporting for the Times, Salazar forged relationships with members of the Chicano movement, including Rosalio Munoz where he reported on Munoz's draft protest.[5]

In January 1970, Salazar left the Times to serve as the news director for the Spanish language television station KMEX in Los Angeles. At KMEX, he investigated allegations of police officers' planting evidence to implicate Chicanos and the July 1970 police shooting of two unarmed Mexican nationals. According to Salazar, he was visited by undercover LAPD detectives who warned him that his investigations were "dangerous in the minds of barrio people."[2]

During Salazar's time as the news director for KMEX, which was a Spanish language station, he became more outspoken on Chicano issues and gave priority to cases that were important to the Chicano Movement. This included the killing of the Sanchez cousins by police which brought forth a community wide protest as well as covering the Chicano Moratorium which ultimately led to his death.[5]

Due to his support of the Chicano movement, Ruben Salazar became an FBI target and was the subject of an FBI internal subject file. While Salazar was noted as being cooperative during his interactions with the FBI around the investigation of Stokely Carmichael he drew the FBI's attention during the Korean War when he began corresponding with a white female pacifist regarding the loss of his application for US citizenship by the army During his Carmichael interview, he is noted as saying that he could not be a witness to the speech that FBI was referencing as he was not present to which he was then asked to obtain a video of the speech to present to the FBI. While Salazar accepted, he did so under the notion that he would publicize the fact that the FBI was looking for the tape.[7] As they feared the civil unrest this could cause if publicized, the FBI rescinded their request. Due to the fact that the FBI and the LAPD correlated civil unrest with communism, and Salazar reported at many events where civil unrest occurred, he was viewed in his files as a community. While Salazar was in fact critical of the Vietnam War, he was not a communist. LAPD also held files on Salazar specifically due to an article that Salazar wrote about the Chief of Police, Chief Davis, wherein he reported the fact that Davis referred to Mexican "tyranny and dictatorship".[7]  While local and national law enforcement were displeased with Salazar's reporting, he continued to write articles advocating the rights of his people- the Chicano community.[7]

On August 29, 1970, he was covering the National Chicano Moratorium March, organized to protest the Vietnam War, in which some believed that a disproportionate number of Latinos served and were killed. The march ended with a rally that was broken up by the Los Angeles County Sheriff's Department using tear gas. Panic and rioting ensued.[8] A coroner's inquest ruled the shooting of the tear gas canister a homicide, but Tom Wilson, the sheriff's deputy involved, was never prosecuted.  At the time, many believed the homicide was a premeditated assassination of a prominent, vocal member of the Los Angeles Chicano community.

The riot started when the owners of the Green Mill liquor store, located around the corner from the Silver Dollar Bar on Whittier Boulevard, called in a complaint about people stealing from them. Deputies responded and a fight broke out. Later on that day, cadets from the nearby Sheriff's Academy were bused to the area and marched into the park. A fight ensued, with the untrained cadets being beaten up.  This led to more rioting. The Green Mill liquor store is still located at the same place on Whittier Boulevard. The owners later denied contacting the Sheriff's Department.

Salazar was resting in the Silver Dollar Bar after protest became violent.  According to a witness, "Ruben Salazar had just sat down to sip a quiet beer at the bar, away from the madness in the street, when a deputy fired a tear gas projectile" at a crowd which went into the interior of the bar, hitting Salazar in the head and killing him instantly. The sheriff's deputy fired a 10-inch wall-piercing type of tear gas round from a tear gas guns of the type intended for barricade situation, rather than the type of tear gas round designed to be fired directly at people (which produces a plume of tear gas smoke). The deputy was found to have mistakenly loaded the wrong type of tear gas round, as the two types of cylinders were nearly identical.

The story of Salazar's killing was the subject of "Strange Rumblings in Aztlan," a 1971 article by gonzo journalist Hunter S. Thompson for Rolling Stone magazine.[9] On February 22, 2011 the Office of Independent Review released a report of its examination of the Los Angeles Sheriff's Department records on the death of Salazar. After reviewing thousands of documents, the civilian watchdog agency concluded there is no evidence that sheriff's deputies intentionally targeted Salazar or had him under surveillance.[10]

Although sheriff's deputy Thomas Wilson was identified as responsible for Salazar's death, he said that "he did not know, and under the circumstances was not concerned about, what kind of tear gas projectile he fired" at the time.[11] Salazar's death captured the attention of many activists within the Chicano movement as his death occurred at the hands of those whom the movement felt was a large cause of the marginalizing of Chicano communities. During meetings with the district attorney in regards to the incident that led to Salazar's death, many Chicanos attended to voice their support as well as show a united force against police brutality.[5] After several days of testimony, a coroner's jury returned with a split verdict, and no charges were filed by the District Attorney. Nevertheless, three years after Salazar's death, Los Angeles County reached a settlement of $700,000 with Salazar's family as a result of the sheriff's department not using "proper and lawful guidelines for the use of deadly force" during the march. At the time, this was the highest settlement recorded in Los Angeles county history.[citation needed]


what is the name of the rover from nasa exploring mars

On January 24, 2014, NASA reported that current studies by the remaining rover Opportunity as well as by the newer Mars Science Laboratory rover Curiosity will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[10][11][12][13] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[10]

Mars Exploration Rover

NASA's Mars Exploration Rover (MER) mission is an ongoing robotic space mission involving two Mars rovers, Spirit[1] and Opportunity,[2] exploring the planet Mars. It began in 2003 with the launch of the two rovers: MER-A Spirit and MER-B Opportunityâ€”to explore the Martian surface and geology; both landed on Mars at separate locations in January 2004. Both rovers far outlived their planned missions of 90 Martian solar days: MER-A Spirit was active until 2010, while MER-B Opportunity is still active in 2018, and holds the record for the longest distance driven by any off-Earth wheeled vehicle.

The mission's scientific objective was to search for and characterize a wide range of rocks and soils that hold clues to past water activity on Mars. The mission is part of NASA's Mars Exploration Program, which includes three previous successful landers: the two Viking program landers in 1976 and Mars Pathfinder probe in 1997.[3]

The total cost of building, launching, landing and operating the rovers on the surface for the initial 90-sol primary mission was US$820 million.[4] Since the rovers have continued to function beyond their initial 90 sol primary mission, they have each received five mission extensions. The fifth mission extension was granted in October 2007, and ran to the end of 2009.[4][5] The total cost of the first four mission extensions was $104 million, and the fifth mission extension is expected to cost at least $20 million.[4]

In July 2007, during the fourth mission extension, Martian dust storms blocked sunlight to the rovers and threatened the ability of the craft to gather energy through their solar panels, causing engineers to fear that one or both of them might be permanently disabled. However, the dust storms lifted, allowing them to resume operations.[6]

On May 1, 2009, during its fifth mission extension, Spirit became stuck in soft soil on Mars.[7] After nearly nine months of attempts to get the rover back on track, including using test rovers on Earth, NASA announced on January 26, 2010 that Spirit was being retasked as a stationary science platform. This mode would enable Spirit to assist scientists in ways that a mobile platform could not, such as detecting "wobbles" in the planet's rotation that would indicate a liquid core.[8] Jet Propulsion Laboratory (JPL) lost contact with Spirit after last hearing from the rover on March 22, 2010 and continued attempts to regain communications lasted until May 25, 2011, bringing the elapsed mission time to 6 years 2 months 19 days, or over 25 times the original planned mission duration.[9]

In recognition of the vast amount of scientific information amassed by both rovers, two asteroids have been named in their honor: 37452 Spirit and 39382 Opportunity. The mission is managed for NASA by the Jet Propulsion Laboratory, which designed, built, and is operating the rovers.

The scientific objectives of the Mars Exploration Rover mission are to:[14]

The MER-A and MER-B probes were launched on June 10, 2003 and July 7, 2003, respectively. Though both probes launched on Boeing Delta II 7925-9.5 rockets from Cape Canaveral Air Force Station Space Launch Complex 17 (CCAFS SLC-17), MER-B was on the heavy version of that launch vehicle, needing the extra energy for Trans-Mars injection. The launch vehicles were integrated onto pads right next to each other,[15] with MER-A on CCAFS SLC-17A and MER-B on CCAFS SLC-17B. The dual pads allowed for working the 15- and 21-day planetary launch periods close together; the last possible launch day for MER-A was June 19, 2003 and the first day for MER-B was June 25, 2003. NASA's Launch Services Program managed the launch of both spacecraft.

The probes landed in January 2004 in widely separated equatorial locations on Mars.

On January 21, 2004, the Deep Space Network lost contact with Spirit, for reasons originally thought to be related to a thunderstorm over Australia. The rover transmitted a message with no data, but later that day missed another communications session with the Mars Global Surveyor. The next day, JPL received a beep from the rover, indicating that it was in fault mode. On January 23, the flight team succeeded in making the rover send. The fault was believed to have been caused by an error in the rover's flash memory subsystem. The rover did not perform any scientific activities for ten days, while engineers updated its software and ran tests. The problem was corrected by reformatting Spirit's flash memory and using a software patch to avoid memory overload; Opportunity was also upgraded with the patch as a precaution. Spirit returned to full scientific operations by February 5.

On March 23, 2004, a news conference was held announcing "major discoveries" of evidence of past liquid water on the Martian surface. A delegation of scientists showed pictures and data revealing a stratified pattern and cross bedding in the rocks of the outcrop inside a crater in Meridiani Planum, landing site of MER-B, Opportunity. This suggested that water once flowed in the region. The irregular distribution of chlorine and bromine also suggests that the place was once the shoreline of a salty sea, now evaporated.

On April 8, 2004, NASA announced that it was extending the mission life of the rovers from three to eight months. It immediately provided additional funding of US $15 million through September, and $2.8 million per month for continuing operations. Later that month, Opportunity arrived at Endurance crater, taking about five days to drive the 200 meters. NASA announced on September 22 that it was extending the mission life of the rovers for another six months. Opportunity was to leave Endurance crater, visit its discarded heat shield, and proceed to Victoria crater. Spirit was to attempt to climb to the top of the Columbia Hills.

With the two rovers still functioning well, NASA later announced another 18-month extension of the mission to September 2006. Opportunity was to visit the "Etched Terrain" and Spirit was to climb a rocky slope toward the top of Husband Hill. On August 21, 2005, Spirit reached the summit of Husband Hill after 581 sols and a journey of 4.81 kilometers (2.99Â mi).

Spirit celebrated its one Martian year anniversary (669 sols or 687 Earth days) on November 20, 2005. Opportunity celebrated its anniversary on December 12, 2005. At the beginning of the mission, it was expected that the rovers would not survive much longer than 90 Martian days. The Columbia Hills were "just a dream", according to rover driver Chris Leger. Spirit explored the semicircular rock formation known as Home Plate. It is a layered rock outcrop that puzzles and excites scientists.[16] It is thought that its rocks are explosive volcanic deposits, though other possibilities exist, including impact deposits or sediment borne by wind or water.

Spirit's front right wheel ceased working on March 13, 2006, while the rover was moving itself to McCool Hill. Its drivers attempted to drag the dead wheel behind Spirit, but this only worked until reaching an impassable sandy area on the lower slopes. Drivers directed Spirit to a smaller sloped feature, dubbed "Low Ridge Haven", where it spent the long Martian winter, waiting for spring and increased solar power levels suitable for driving. That September, Opportunity reached the rim of Victoria crater, and Spaceflight Now reported that NASA had extended mission for the two rovers through September 2007.[17][18] On February 6, 2007, Opportunity became the first spacecraft to traverse ten kilometers (6.2 miles) on the surface of Mars.[19]

Opportunity was poised to enter Victoria Crater from its perch on the rim of Duck Bay on June 28, 2007,[20] but due to extensive dust storms, it was delayed until the dust had cleared and power returned to safe levels.[21] Two months later, Spirit and Opportunity resumed driving after hunkering down during raging dust storms that limited solar power to a level that nearly caused the permanent failure of both rovers.[22]

On October 1, 2007,[23] both Spirit and Opportunity entered their fifth mission extension that extended operations into 2009,[24] allowing the rovers to have spent five years exploring the Martian surface, pending their continued survival.

On August 26, 2008, Opportunity began its three-day climb out of Victoria crater amidst concerns that power spikes, similar to those seen on Spirit before the failure of its right-front wheel, might prevent it from ever being able to leave the crater if a wheel failed. Project scientist Bruce Banerdt also said, "We've done everything we entered Victoria Crater to do and more." Opportunity will return to the plains in order to characterize Meridiani Planum's vast diversity of rocks—some of which may have been blasted out of craters such as Victoria. The rover had been exploring Victoria Crater since September 11, 2007.[25][26] As of January 2009, the two rovers had collectively sent back 250,000 images and traveled over 21 kilometers (13 mi).[27]

After driving about 3.2 kilometers (2.0 mi) since it left Victoria crater, Opportunity first saw the rim of Endeavour crater on March 7, 2009.[28][29] It passed the 16 km (9.9 mi) mark along the way on sol 1897.[30] Meanwhile, at Gusev crater, Spirit was dug in deep into the Martian sand, much as Opportunity was at Purgatory Dune in 2005.[31]

On January 3 and January 24, 2010, Spirit and Opportunity marked six years on Mars, respectively.[32] On January 26, NASA announced that Spirit will be used as a stationary research platform after several months of unsuccessful attempts to free the rover from soft sand.[33]

NASA announced on March 24, 2010, that Opportunity, which has an estimated remaining drive distance of 12 km to Endeavour Crater, has traveled over 20 km since the start of its mission.[34] Each rover was designed with a mission driving distance goal of just 600 meters.[34] One week later, they announced that Spirit may have gone into hibernation for the Martian winter and might not wake up again for months.[35]

On September 8, 2010, it was announced that Opportunity had reached the halfway point of the 19-kilometer journey between Victoria crater and Endeavour crater.[36]

On May 22, 2011, NASA announced that it will cease attempts to contact Spirit, which has been stuck in a sand trap for two years. The last successful communication with the rover was on March 22, 2010. The final transmission to the rover was on May 25, 2011.[37]

In April 2013, a photo sent back by one of the rovers became widely circulated on social networking and news sites such as Reddit that appeared to depict a human penis carved into the Martian dirt.[38][39]

On May 16, 2013, NASA announced that Opportunity had driven further than any other NASA vehicle on a world other than Earth.[40] After Opportunity's total odometry went over 35.744 km (22.210 mi), the rover surpassed the total distance driven by the Apollo 17 Lunar Roving Vehicle.[40]

On July 28, 2014, NASA announced that Opportunity had driven further than any other vehicle on a world other than Earth.[40][41][42] Opportunity covered over 40 km (25 mi), surpassing the total distance of 39 km (24 mi) driven by the Lunokhod 2 lunar rover, the previous record-holder.[40][41]

On March 23, 2015, NASA announced that Opportunity had driven the full 42.2 km (26.2 mi) distance of a marathon, with a finish time of roughly 11 years, 2 months.[43]

The Mars Exploration Rover was designed to be stowed in the nose of a Delta II rocket. Each spacecraft consists of several components:

Total mass is 1,063 kg (2,344 lb).

The cruise stage is the component of the spacecraft that is used for travel from Earth to Mars. It is very similar to the Mars Pathfinder in design and is approximately 2.65 meters (8.7 ft) in diameter and 1.6 m (5.2 ft) tall, including the entry vehicle (see below).

The primary structure is aluminium with an outer ring of ribs covered by the solar panels, which are about 2.65 m (8.7 ft) in diameter. Divided into five sections, the solar arrays can provide up to 600 watts of power near Earth and 300 W at Mars.

Heaters and multi-layer insulation keep the electronics "warm". A freon system removes heat from the flight computer and communications hardware inside the rover so they do not overheat. Cruise avionics systems allow the flight computer to interface with other electronics, such as the sun sensors, star scanner and heaters.

The star scanner (without a backup system) and sun sensor allowed the spacecraft to know its orientation in space by analyzing the position of the Sun and other stars in relation to itself. Sometimes the craft could be slightly off course; this was expected, given the 500-million-kilometer (320Â million mile) journey. Thus navigators planned up to six trajectory correction maneuvers, along with health checks.

To ensure the spacecraft arrived at Mars in the right place for its landing, two light-weight, aluminium-lined tanks carried about 31 kg (about 68 lb) of hydrazine propellant. Along with cruise guidance and control systems, the propellant allowed navigators to keep the spacecraft on course. Burns and pulse firings of the propellant allowed three types of maneuvers:

The spacecraft used a high-frequency X band radio wavelength to communicate, which allowed for less power and smaller antennas than many older craft, which used S band.

Navigators sent commands through two antennas on the cruise stage: a cruise low-gain antenna mounted inside the inner ring, and a cruise medium-gain antenna in the outer ring. The low-gain antenna was used close to Earth. It is omni-directional, so the transmission power that reached Earth fell faster with increasing distance. As the craft moved closer to Mars, the Sun and Earth moved closer in the sky as viewed from the craft, so less energy reached Earth. The spacecraft then switched to the medium-gain antenna, which directed the same amount of transmission power into a tighter beam toward Earth.

During flight, the spacecraft was spin-stabilized with a spin rate of two revolutions per minute (rpm). Periodic updates kept antennas pointed toward Earth and solar panels toward the Sun.

The aeroshell maintained a protective covering for the lander during the seven-month voyage to Mars. Together with the lander and the rover, it constituted the "entry vehicle". Its main purpose was to protect the lander and the rover inside it from the intense heat of entry into the thin Martian atmosphere. It was based on the Mars Pathfinder and Mars Viking designs.

The aeroshell was made of two main parts: a heat shield and a backshell. The heat shield was flat and brownish, and protected the lander and rover during entry into the Martian atmosphere and acted as the first aerobrake for the spacecraft. The backshell was large, cone-shaped and painted white. It carried the parachute and several components used in later stages of entry, descent, and landing, including:

Built by the Lockheed Martin Astronautics Co. in Denver, Colorado, the aeroshell is made of an aluminium honeycomb structure sandwiched between graphite-epoxy face sheets. The outside of the aeroshell is covered with a layer of phenolic honeycomb. This honeycomb is filled with an ablative material (also called an "ablator"), that dissipates heat generated by atmospheric friction.

The ablator itself is a unique blend of cork wood, binder and many tiny silica glass spheres. It was invented for the heat shields flown on the Viking Mars lander missions. A similar technology was used in the first US manned space missions Mercury, Gemini and Apollo. It was specially formulated to react chemically with the Martian atmosphere during entry and carry heat away, leaving a hot wake of gas behind the vehicle. The vehicle slowed from 19,000 to 1,600 km/h (5,300 to 440 m/s) in about a minute, producing about 60 m/s2 (6 g) of acceleration on the lander and rover.

The backshell and heat shield are made of the same materials, but the heat shield has a thicker, 13 mm (1⁄2 in), layer of the ablator. Instead of being painted, the backshell was covered with a very thin aluminized PET film blanket to protect it from the cold of deep space. The blanket vaporized during entry into the Martian atmosphere.

The parachute helped slow the spacecraft during entry, descent, and landing. It is located in the backshell.[45]

The 2003 parachute design was part of a long-term Mars parachute technology development effort and is based on the designs and experience of the Viking and Pathfinder missions. The parachute for this mission is 40% larger than Pathfinder's because the largest load for the Mars Exploration Rover is 80 to 85 kilonewtons (kN) or 80 to 85 kN (18,000 to 19,000 lbf) when the parachute fully inflates. By comparison, Pathfinder's inflation loads were approximately 35 kN (about 8,000 lbf). The parachute was designed and constructed in South Windsor, Connecticut by Pioneer Aerospace, the company that also designed the parachute for the Stardust mission.[45]

The parachute is made of two durable, lightweight fabrics: polyester and nylon. A triple bridle made of Kevlar connects the parachute to the backshell.

The amount of space available on the spacecraft for the parachute is so small that the parachute had to be pressure-packed. Before launch, a team tightly folded the 48 suspension lines, three bridle lines, and the parachute. The parachute team loaded the parachute in a special structure that then applied a heavy weight to the parachute package several times. Before placing the parachute into the backshell, the parachute was heat set to sterilize it.[45]

Zylon Bridles: After the parachute was deployed at an altitude of about 10 km (6.2 mi) above the surface, the heatshield was released using 6 separation nuts and push-off springs. The lander then separated from the backshell and "rappelled" down a metal tape on a centrifugal braking system built into one of the lander petals. The slow descent down the metal tape placed the lander in position at the end of another bridle (tether), made of a nearly 20 m (66 ft) long braided Zylon.[45]

Zylon is an advanced fiber material, similar to Kevlar, that is sewn in a webbing pattern (like shoelace material) to make it stronger. The Zylon bridle provides space for airbag deployment, distance from the solid rocket motor exhaust stream, and increased stability. The bridle incorporates an electrical harness that allows the firing of the solid rockets from the backshell as well as provides data from the backshell inertial measurement unit (which measures rate and tilt of the spacecraft) to the flight computer in the rover.[45]

Rocket assisted descent (RAD) motors: Because the atmospheric density of Mars is less than 1% of Earth's, the parachute alone could not slow down the Mars Exploration Rover enough to ensure a safe, low landing speed. The spacecraft descent was assisted by rockets that brought the spacecraft to a dead stop 10–15 m (33–49 ft) above the Martian surface.[45]

Radar altimeter unit: A radar altimeter unit was used to determine the distance to the Martian surface. The radar's antenna is mounted at one of the lower corners of the lander tetrahedron. When the radar measurement showed the lander was the correct distance above the surface, the Zylon bridle was cut, releasing the lander from the parachute and backshell so that it was free and clear for landing. The radar data also enabled the timing sequence on airbag inflation and backshell RAD rocket firing.[45]

Airbags used in the Mars Exploration Rover mission are the same type that Mars Pathfinder used in 1997. They had to be strong enough to cushion the spacecraft if it landed on rocks or rough terrain and allow it to bounce across Mars' surface at highway speeds (about 100Â km/h) after landing. The airbags had to be inflated seconds before touchdown and deflated once safely on the ground.

The airbags were made of Vectran, like those on Pathfinder. Vectran has almost twice the strength of other synthetic materials, such as Kevlar, and performs better in cold temperatures. Six 100 denier (10 mg/m) layers of Vectran protected one or two inner bladders of Vectran in 200 denier (20 mg/m). Using 100 denier (10 mg/m) leaves more fabric in the outer layers where it is needed, because there are more threads in the weave.

Each rover used four airbags with six lobes each, all of which were connected. Connection was important, since it helped abate some of the landing forces by keeping the bag system flexible and responsive to ground pressure. The airbags were not attached directly to the rover, but were held to it by ropes crisscrossing the bag structure. The ropes gave the bags shape, making inflation easier. While in flight, the bags were stowed along with three gas generators that are used for inflation.

The spacecraft lander is a protective shell that houses the rover, and together with the airbags, protects it from the forces of impact.

The lander is a tetrahedron shape, whose sides open like petals. It is strong and light, and made of beams and sheets. The beams consist of layers of graphite fiber woven into a fabric that is lighter than aluminium and more rigid than steel. Titanium fittings are glued and fitted onto the beams to allow it to be bolted together. The rover was held inside the lander by bolts and special nuts that were released after landing with small explosives.

After the lander stopped bouncing and rolling on the ground, it came to rest on the base of the tetrahedron or one of its sides. The sides then opened to make the base horizontal and the rover upright. The sides are connected to the base by hinges, each of which has a motor strong enough to lift the lander. The rover plus lander has a mass of about 533 kilograms (1,175 pounds). The rover alone has a mass of about 185 kg (408 lb). The gravity on Mars is about 38% of Earth's, so the motor does not need to be as powerful as it would on Earth.

The rover contains accelerometers to detect which way is down (toward the surface of Mars) by measuring the pull of gravity. The rover computer then commanded the correct lander petal to open to place the rover upright. Once the base petal was down and the rover was upright, the other two petals were opened.

The petals initially opened to an equally flat position, so all sides of the lander were straight and level. The petal motors are strong enough so that if two of the petals come to rest on rocks, the base with the rover would be held in place like a bridge above the ground. The base will hold at a level even with the height of the petals resting on rocks, making a straight flat surface throughout the length of the open, flattened lander. The flight team on Earth could then send commands to the rover to adjust the petals and create a safe path for the rover to drive off the lander and onto the Martian surface without dropping off a steep rock.

The moving of the rover off the lander is called the egress phase of the mission. The rover must avoid having its wheels caught in the airbag material or falling off a sharp incline. To help this, a retraction system on the petals slowly drags the airbags toward the lander before the petals open. Small ramps on the petals fan out to fill spaces between the petals. They cover uneven terrain, rock obstacles, and airbag material, and form a circular area from which the rover can drive off in more directions. They also lower the step that the rover must climb down. They are nicknamed "batwings", and are made of Vectran cloth.

About three hours were allotted to retract the airbags and deploy the lander petals.

The rovers are six-wheeled, solar-powered robots that stand 1.5 m (4.9 ft) high, 2.3 m (7.5 ft) wide and 1.6 m (5.2 ft) long. They weigh 180 kg (400 lb), 35 kg (77 lb) of which is the wheel and suspension system.[46]

Each rover has six wheels mounted on a rocker-bogie suspension system that ensures wheels remain on the ground while driving over rough terrain. The design reduces the range of motion of the rover body by half, and allows the rover to go over obstacles or through holes that are more than a wheel diameter (250 millimeters (9.8Â in)) in size. The rover wheels are designed with integral compliant flexures which provide shock absorption during movement.[47] Additionally, the wheels have cleats which provide grip for climbing in soft sand and scrambling over rocks.

Each wheel has its own drive motor. The two front and two rear wheels each have individual steering motors. This allows the vehicle to turn in place, a full revolution, and to swerve and curve, making arching turns. The rover is designed to withstand a tilt of 45 degrees in any direction without overturning. However, the rover is programmed through its "fault protection limits" in its hazard avoidance software to avoid exceeding tilts of 30 degrees.

Each rover can spin one of its front wheels in place to grind deep into the terrain. It is to remain motionless while the digging wheel is spinning. The rovers have a top speed on flat hard ground of 50 mm/s (2 in/s). The average speed is 10 mm/s, because its hazard avoidance software causes it to stop every 10 seconds for 20 seconds to observe and understand the terrain into which it has driven.

When fully illuminated, the rover triplejunction[48] solar arrays generate about 140 watts for up to four hours per Martian day (sol). The rover needs about 100 watts to drive. Its power system includes two rechargeable lithium ion batteries weighing 7.15 kg (15.8 lb) each, that provide energy when the sun is not shining, especially at night. Over time, the batteries will degrade and will not be able to recharge to full capacity.

For comparison, the Mars Science Laboratory's power system is composed of a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) produced by Boeing.[49] The MMRTG is designed to provide 125W of electrical power at the start of the mission, falling to 100W after 14 years of service.[50] It is used to power the MSL's many systems and instruments. Solar panels were also considered for the MSL, but RTGs provide constant power, regardless of the time of day, and thus the versatility to work in dark environments and high latitudes where solar energy is not readily available. The MSL generates 2.5 kilowatt hours per day, compared to the Mars Exploration Rovers, which can generate about 0.6 kilowatt hours per day.[51]

It was thought that by the end of the 90-sol mission, the capability of the solar arrays to generate power would likely be reduced to about 50 watts. This was due to anticipated dust coverage on the solar arrays, and the change in season. Over three Earth years later, however, the rovers' power supplies hovered between 300 watt-hours and 900 watt-hours per day, depending on dust coverage. Cleaning events (dust removal by wind) have occurred more often than NASA expected, keeping the arrays relatively free of dust and extending the life of the mission. During a 2007 global dust storm on Mars, both rovers experienced some of the lowest power of the mission; Opportunity dipped to 128 watt-hours. In November 2008, Spirit had overtaken this low-energy record with a production of 89 watt-hours, due to dust storms in the region of Gusev crater.[52]

The rovers run a VxWorks embedded operating system on a radiation-hardened 20 MHz RAD6000 CPU with 128 MB of DRAM with error detection and correction and 3 MB of EEPROM. Each rover also has 256 MB of flash memory. To survive during the various mission phases, the rover's vital instruments must stay within a temperature of −40 °C to +40 °C (−40 °F to 104 °F). At night, the rovers are heated by eight radioisotope heater units (RHU), which each continuously generate 1 W of thermal energy from the decay of radioisotopes, along with electrical heaters that operate only when necessary. A sputtered gold film and a layer of silica aerogel are used for insulation.

The rover has an X band low-gain and an X band high-gain antenna for communications to and from the Earth, as well as an ultra high frequency monopole antenna for relay communications. The low-gain antenna is omnidirectional, and transmits data at a low rate to Deep Space Network (DSN) antennas on Earth. The high-gain antenna is directional and steerable, and can transmit data to Earth at a higher rate. The rovers use the UHF monopole and its CE505 radio to communicate with spacecraft orbiting Mars, the Mars Odyssey and (before its failure) the Mars Global Surveyor (already more than 7.6 terabits of data were transferred using its Mars Relay antenna and Mars Orbiter Camera's memory buffer of 12 MB).[53] Since MRO went into orbit around Mars, the landers have also used it as a relay asset. Most of the lander data is relayed to Earth through Odyssey and MRO. The orbiters can receive rover signals at a much higher data rate than the Deep Space Network can, due to the much shorter distances from rover to orbiter. The orbiters then quickly relay the rover data to the Earth using their large and high-powered antennas.

Each rover has nine cameras, which produce 1024-pixel by 1024-pixel images at 12 bits per pixel,[54] but most navigation camera images and image thumbnails are truncated to 8 bits per pixel to conserve memory and transmission time. All images are then compressed using ICER before being stored and sent to Earth. Navigation, thumbnail, and many other image types are compressed to approximately 0.8 to 1.1 bits/pixel. Lower bit rates (less than 0.5-bit/pixel) are used for certain wavelengths of multi-color panoramic images.

ICER is based on wavelets, and was designed specifically for deep-space applications. It produces progressive compression, both lossless and lossy, and incorporates an error-containment scheme to limit the effects of data loss on the deep-space channel. It outperforms the lossy JPEG image compressor and the lossless Rice compressor used by the Mars Pathfinder mission.

The rover has various instruments. Three are mounted on the Pancam Mast Assembly (PMA):

The cameras are mounted 1.5 meters high on the Pancam Mast Assembly. The PMA is deployed via the Mast Deployment Drive (MDD). The Azimuth Drive, mounted directly above the MDD, turns the assembly horizontally a whole revolution with signals transmitted through a rolling tape configuration. The camera drive points the cameras in elevation, almost straight up or down. A third motor points the Mini-TES fold mirrors and protective shroud, up to 30° above the horizon and 50° below. The PMA's conceptual design was done by Jason Suchman at JPL, the Cognizant Engineer who later served as Contract Technical Manager (CTM) once the assembly was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. Raul Romero served as CTM once subsystem-level testing began. Satish Krishnan did the conceptual design of the High-Gain Antenna Gimbal (HGAG), whose detailed design, assembly, and test was also performed by Ball Aerospace at which point Satish acted as the CTM.

Four monochromatic hazard cameras (Hazcams) are mounted on the rover's body, two in front and two behind.

The instrument deployment device (IDD), also called the rover arm, holds the following:

The robotic arm is able to place instruments directly up against rock and soil targets of interest.

The Spirit and Opportunity rovers were named through a student essay competition. The winning entry was by Sofi Collis,[59] a third-grade Russian-American student from Arizona.

I used to live in an orphanage. It was dark and cold and lonely. At night, I looked up at the sparkly sky and felt better. I dreamed I could fly there. In America, I can make all my dreams come true. Thank you for the 'Spirit' and the 'Opportunity.'
â€” Sofi Collis, age 9

Prior to this, during the development and building of the rovers, they were known as MER-1 (Opportunity) and MER-2 (Spirit). Internally, NASA also uses the mission designations MER-A (Spirit) and MER-B (Opportunity) based on the order of landing on Mars (Spirit first then Opportunity).

The Jet Propulsion Laboratory maintains a pair of rovers, the Surface System Test-Beds (SSTB) at its location in Pasadena for testing and modeling of situations on Mars. One test rover, SSTB1, weighing approximately 180 kilograms (400 lb), is fully instrumented and nearly identical to Spirit and Opportunity. Another test version, SSTB-Lite, is identical in size and drive characteristics but does not include all instruments. It weighs in at 80 kilograms (180 lb), much closer to the weight of Spirit and Opportunity in the reduced gravity of Mars. These rovers were used in 2009 for a simulation of the incident in which Spirit became trapped in soft soil.[60][61][62]

The NASA team uses a software application called SAP to view images collected from the rover, and to plan its daily activities. There is a version available to the public called Maestro.[63]

Although the Gusev crater appears from orbital images to be a dry lakebed, the observations from the surface show the interior plains mostly filled with debris. The rocks on the plains of Gusev are a type of basalt. They contain the minerals olivine, pyroxene, plagioclase, and magnetite, and they look like volcanic basalt as they are fine-grained with irregular holes (geologists would say they have vesicles and vugs).[64][65] Much of the soil on the plains came from the breakdown of the local rocks. Fairly high levels of nickel were found in some soils; probably from meteorites.[66] Analysis shows that the rocks have been slightly altered by tiny amounts of water. Outside coatings and cracks inside the rocks suggest water deposited minerals, maybe bromine compounds. All the rocks contain a fine coating of dust and one or more harder rinds of material. One type can be brushed off, while another needed to be ground off by the Rock Abrasion Tool (RAT).[67]

There are a variety of rocks in the Columbia Hills, some of which have been altered by water, but not by very much water.

These rocks can be classified in different ways. The amounts and types of minerals make the rocks primitive basalts—also called picritic basalts. The rocks are similar to ancient terrestrial rocks called basaltic komatiites. Rocks of the plains also resemble the basaltic shergottites, meteorites which came from Mars. One classification system compares the amount of alkali elements to the amount of silica on a graph; in this system, Gusev plains rocks lie near the junction of basalt, picrobasalt, and tephite. The Irvine-Barager classification calls them basalts.[64] Plain’s rocks have been very slightly altered, probably by thin films of water because they are softer and contain veins of light colored material that may be bromine compounds, as well as coatings or rinds. It is thought that small amounts of water may have gotten into cracks inducing mineralization processes).[65][64] Coatings on the rocks may have occurred when rocks were buried and interacted with thin films of water and dust. One sign that they were altered was that it was easier to grind these rocks compared to the same types of rocks found on Earth.

The first rock that Spirit studied was Adirondack. It turned out to be typical of the other rocks on the plains.

First color picture from Gusev crater. Rocks were found to be basalt. Everything was covered with a fine dust that Spirit determined was magnetic because of the mineral magnetite.

Cross-sectional drawing of a typical rock from the plains of Gusev crater. Most rocks contain a coating of dust and one or more harder coatings. Veins of water-deposited veins are visible, along with crystals of olivine. Veins may contain bromine salts.

The dust in Gusev Crater is the same as dust all around the planet. All the dust was found to be magnetic. Moreover, Spirit found the magnetism was caused by the mineral magnetite, especially magnetite that contained the element titanium. One magnet was able to completely divert all dust hence all Martian dust is thought to be magnetic.[68] The spectra of the dust was similar to spectra of bright, low thermal inertia regions like Tharsis and Arabia that have been detected by orbiting satellites. A thin layer of dust, maybe less than one millimeter thick covers all surfaces. Something in it contains a small amount of chemically bound water.[69][70]

As the rover climbed above the plains onto the Columbia Hills, the mineralogy that was seen changed.[71][72] Scientists found a variety of rock types in the Columbia Hills, and they placed them into six different categories. The six are: Clovis, Wishbone, Peace, Watchtower, Backstay, and Independence. They are named after a prominent rock in each group. Their chemical compositions, as measured by APXS, are significantly different from each other.[73] Most importantly, all of the rocks in Columbia Hills show various degrees of alteration due to aqueous fluids.[74] They are enriched in the elements phosphorus, sulfur, chlorine, and bromine—all of which can be carried around in water solutions. The Columbia Hills’ rocks contain basaltic glass, along with varying amounts of olivine and sulfates.[75][76] The olivine abundance varies inversely with the amount of sulfates. This is exactly what is expected because water destroys olivine but helps to produce sulfates.

The Clovis group is especially interesting because the Mössbauer spectrometer (MB) detected goethite in it.[77] Goethite forms only in the presence of water, so its discovery is the first direct evidence of past water in the Columbia Hills's rocks. In addition, the MB spectra of rocks and outcrops displayed a strong decline in olivine presence,[75] although the rocks probably once contained much olivine.[78] Olivine is a marker for the lack of water because it easily decomposes in the presence of water. Sulfate was found, and it needs water to form. Wishstone contained a great deal of plagioclase, some olivine, and anhydrate (a sulfate). Peace rocks showed sulfur and strong evidence for bound water, so hydrated sulfates are suspected. Watchtower class rocks lack olivine consequently they may have been altered by water. The Independence class showed some signs of clay (perhaps montmorillonite a member of the smectite group). Clays require fairly long term exposure to water to form. One type of soil, called Paso Robles, from the Columbia Hills, may be an evaporate deposit because it contains large amounts of sulfur, phosphorus, calcium, and iron.[79] Also, MB found that much of the iron in Paso Robles soil was of the oxidized, Fe3+ form. Towards the middle of the six-year mission (a mission that was supposed to last only 90 days), large amounts of pure silica were found in the soil. The silica could have come from the interaction of soil with acid vapors produced by volcanic activity in the presence of water or from water in a hot spring environment.[80]

After Spirit stopped working scientists studied old data from the Miniature Thermal Emission Spectrometer, or Mini-TES and confirmed the presence of large amounts of carbonate-rich rocks, which means that regions of the planet may have once harbored water. The carbonates were discovered in an outcrop of rocks called "Comanche."[81][82]

In summary, Spirit found evidence of slight weathering on the plains of Gusev, but no evidence that a lake was there. However, in the Columbia Hills there was clear evidence for a moderate amount of aqueous weathering. The evidence included sulfates and the minerals goethite and carbonates which only form in the presence of water. It is believed that Gusev crater may have held a lake long ago, but it has since been covered by igneous materials. All the dust contains a magnetic component which was identified as magnetite with some titanium. Furthermore, the thin coating of dust that covers everything on Mars is the same in all parts of Mars.

The Opportunity rover landed in a small crater, dubbed "Eagle", on the flat plains of Meridiani. The plains of the landing site were characterized by the presence of a large number of small spherules, spherical concretions that were tagged "blueberries" by the science team, which were found both loose on the surface, and also embedded in the rock. These proved to have a high concentration of the mineral hematite, and showed the signature of being formed in an aqueous environment. The layered bedrock revealed in the crater walls showed signs of being sedimentary in nature, and compositional and microscopic-imagery analysis showed this to be primarily with composition of Jarosite, a ferrous sulfate mineral that is characteristically an evaporite that is the residue from the evaporation of a salty pond or sea.[83][84]

The mission has provided substantial evidence of past water activity on Mars. In addition to investigating the "water hypothesis", Opportunity has also obtained astronomical observations and atmospheric data. The extended mission took the rover across the plains to a series of larger craters in the south, with the arrival at the edge of a 25-km diameter crater, Endeavour Crater, eight years after landing. The orbital spectroscopy of this crater rim show the signs of phyllosilicate rocks, indicative of older sedimentary deposits.


what ocean zone does the frilled shark live in

The frilled shark (Chlamydoselachus anguineus) is one of two extant species of shark in the family Chlamydoselachidae, with a wide but patchy distribution in the Atlantic and Pacific Oceans. This species is found over the outer continental shelf and upper continental slope, generally near the bottom, though there is evidence of substantial upward movements. It has been caught as deep as 1,570 m (5,150 ft), although it is uncommon below 1,200 m (3,900 ft).[2] In Suruga Bay, Japan, it is most common at depths of 50–200 m (160–660 ft). Exhibiting several primitive features, the frilled shark has often been termed a living fossil. It reaches a length of 2 m (6.6 ft) and has a dark brown, eel-like body with the dorsal, pelvic, and anal fins placed far back. Its common name comes from the frilly or fringed appearance of its six pairs of gill slits, with the first pair meeting across the throat.

Frilled shark

Seldom observed, the frilled shark may capture prey by bending its body and lunging forward like a snake. The long, extremely flexible jaws enable it to swallow prey whole, while its many rows of small, needle-like teeth make it difficult for the prey to escape. It feeds mainly on cephalopods, as well as bony fishes and other sharks. This species is aplacental viviparous: the embryos emerge from their egg capsules inside the mother's uterus, where they survive primarily on yolk. The gestation period may be as long as three and a half years, the longest of any vertebrate. Litter sizes vary from two to fifteen, and there is no distinct breeding season. Frilled sharks are occasional bycatch in commercial fisheries, but have little economic value.

The frilled shark was first scientifically recognized by German ichthyologist Ludwig Döderlein, who visited Japan between 1879 and 1881 and brought two specimens to Vienna. However, his manuscript describing the species was lost, so the first description of the frilled shark was authored by American zoologist Samuel Garman, working from a 1.5-metre (4 ft 11 in)-long female caught from Sagami Bay in Japan. His account, "An Extraordinary Shark", was published in an 1884 volume of Proceedings of the Essex Institute.[3][4] Garman placed the new species in its own genus and family, and gave it the name Chlamydoselachus anguineus from the Greek chlamy (frill) and selachus (shark), and the Latin anguineus for "eel-like".[5] Other common names for this species include frill shark, lizard shark, scaffold shark, and silk shark.[1][6]

Several early authors believed the frilled shark to be a living representative of otherwise long-extinct groups of elasmobranchs (sharks, rays, and their ancestors), based on its multiple-pointed teeth, the articulation of its upper jaw directly to the cranium behind the eyes (called "amphistyly"), and its "notochord-like" spinal column with indistinct vertebrae.[7] Garman proposed that it was allied with the cladodonts, a now-obsolete taxonomic grouping containing forms that thrived during the Palaeozoic era, such as Cladoselache from the Devonian period (416â€“359 Mya). His contemporaries Theodore Gill and Edward Drinker Cope suggested it was instead related to the hybodonts, which were the dominant sharks during the Mesozoic era. Cope went as far as to assign this species to the fossil genus Didymodus.[8][9]

More recent investigations have found the similarities between the frilled shark and extinct groups may have been overstated or misinterpreted, and this shark exhibits a number of skeletal and muscular traits that firmly place it with the neoselachians (modern sharks and rays), and more specifically with the cow sharks in the order Hexanchiformes (though systematist Shigeru Shirai has proposed that it be placed in its own order, Chlamydoselachiformes).[7][9] Nevertheless, the frilled shark belongs to one of the oldest still-extant shark lineages, dating back to at least the Late Cretaceous (about 95 Mya) and possibly to the Late Jurassic (150 Mya).[10] Because of their ancient ancestry and primitive characteristics, the frilled shark and other members of this lineage have been described as a living fossil.[4] However, the frilled shark itself is a relatively recent species, with the earliest known fossil teeth belonging to this species dating to the early Pleistocene epoch.[11]

Rather uncommon, the frilled shark has been recorded from a number of widely scattered locations in the Atlantic and Pacific Oceans. In the eastern Atlantic, it occurs off northern Norway, northern Scotland, and western Ireland, from France to Morocco including Madeira, and off Mauritania.[12] In the central Atlantic, it has been caught at several locations along the Mid-Atlantic Ridge, from north of the Azores to the Rio Grande Rise off southern Brazil, as well as over the Vavilov Ridge off West Africa. In the western Atlantic, it has been reported from waters off New England, Georgia, and Suriname.[13][14][15] In the western Pacific, it is known from southeastern Honshu, Japan, to Taiwan, off New South Wales and Tasmania in Australia, and around New Zealand. In the central and eastern Pacific, it has been found off Hawaii, California, and northern Chile.[1][12] The frilled sharks off southern Africa were described as a different species, C. africana, in 2009.[15]

The frilled shark inhabits the outer continental shelf and upper to middle continental slope, seeming to favor upwellings and other biologically productive areas.[5] Though it has been caught from a depth of 1,570 m (5,150 ft), it usually does not occur deeper than 1,000 m (3,300 ft).[1][6] In Suruga Bay, it is most common at a depth of 50–200 m (160–660 ft), except from August to November when the temperature at the 100 m (330 ft) water layer exceeds 15 °C (59 °F) and the sharks shift into deeper water.[16][17] On rare occasions, this species has been seen at the surface.[12] The frilled shark is usually found close to the bottom, with one individual observed swimming over an area of small sand dunes.[1][13] However, its diet suggests that it does make substantial forays upward into open water.[18] This species may make vertical migrations, approaching the surface at night to feed.[5] There is spatial segregation by size and reproductive condition.[17]

With its elongated, eel-like body and strange appearance, the frilled shark has long been likened to the mythical sea serpent. The head is broad and flattened with a short, rounded snout. The nostrils are vertical slits, separated into incurrent and excurrent openings by a leading flap of skin. The moderately large eyes are horizontally oval and lack nictitating membranes (protective third eyelids). The very long jaws are positioned terminally (at the end of the snout), as opposed to the underslung jaws of most sharks. The corners of the mouth are devoid of furrows or folds. The tooth rows are rather widely spaced, numbering 19–28 in the upper jaw and 21–29 in the lower jaw.[3][15] The teeth number around 300 in all; each tooth is small, with three slender, needle-like cusps alternating with two cusplets.[5][18] There are six pairs of long gill slits with a frilly appearance created by the extended tips of the gill filaments, giving this shark its name. The first pair of gill slits meet across the throat, forming a collar.[3]

The pectoral fins are short and rounded. The single, small dorsal fin is positioned far back on the body, about opposite the anal fin, and has a rounded margin. The pelvic and anal fins are large, broad, and rounded, and also positioned well back on the body. The caudal fin is very long and roughly triangular, without a lower lobe or a ventral notch on the upper lobe. There are a pair of thick skin folds of unknown function running along the belly, separated by a groove.[3] The midsection is relatively longer in females than in males, with the pelvic fins pushed closer to the anal fin.[18][19] The dermal denticles are small and shaped like the tip of a chisel, becoming enlarged and sharp on the dorsal margin of the caudal fin.[3] This species is a uniform dark brown or gray.[5] The frilled shark differs from its southern African relative, C. africana, in having more vertebrae (160–171 vs 147) and more turns in the spiral valve intestine (35–49 versus 26–28), as well as in various proportional measurements such as a longer head and shorter gill slits.[15] The maximum known length is 1.7 m (5.6 ft) for males and 2.0 m (6.6 ft) for females.[5]

Highly specialized for life in the deep sea, the frilled shark has a reduced, poorly calcified skeleton and an enormous liver filled with low-density lipids, allowing it to maintain its position in the water column with little effort.[18] It is one of the few sharks with an "open" lateral line, in which the mechanoreceptive hair cells are positioned in grooves that are directly exposed to the surrounding seawater. This configuration is thought to be basal in sharks and may enhance its sensitivity to the minute movements of its prey.[18][20] Many frilled sharks are found with the tips of their tails missing, probably from predatory attacks by other shark species.[17] Parasites identified from this shark include a tapeworm in the genus Monorygma, the fluke Otodistomum veliporum,[21] and the nematode Mooleptus rabuka.[22]

Fossils of frilled sharks from the Takatika Grit of the Chatham Islands in New Zealand, dated to the Cretaceous–Paleogene boundary, were found together with those of birds and conifer cones, which suggests that the sharks lived in shallow waters at that time. Previous research on other Chlamydoselachus species has shown that individuals living in shallower water had larger and stronger teeth for eating hard-shelled invertebrates. It has been hypothesized that frilled sharks, surviving the mass extinction of the K-T boundary event, were able to make use of vacated niches in shallow water and on continental shelves, the latter opening up a move to the deep-water habitats they now inhabit. Changing food availability may be reflected in how tooth morphology has shifted to become sharper and inward-pointing to prey on soft-bodied deep-sea animals. From the Late Paleocene to the present, frilled sharks may have been out-competed, restricting them to their current habitats and distribution.[23]

The long jaws of the frilled shark are highly distensible with an extremely wide gape, allowing it to swallow whole prey over one-half its size.[5] However, the length and articulation of its jaws means that it cannot deliver as strong a bite as more conventionally built sharks.[24] Most captured individuals are found with no or barely identifiable stomach contents, suggesting a fast digestion rate and/or long intervals between feedings.[16] This species preys on cephalopods, bony fishes, and smaller sharks.[5] One 1.6 m (5.2 ft) long individual, caught off Chōshi, was found to have swallowed a 590 g (1.30 lb) Japanese catshark (Apristurus japonicus).[18] Squid comprise some 60% of the diet of sharks in Suruga Bay; this includes not only slow-moving, deep-dwelling types, such as Chiroteuthis and Histioteuthis, but also relatively large, powerful swimmers of the open ocean, such as Onychoteuthis, Sthenoteuthis, and Todarodes.[16]

How the ostensibly weak-swimming frilled shark captures active, fast-moving squid is a matter of speculation. One possibility is that it takes advantage of injured squid, or those that are exhausted and dying after spawning.[16] Alternatively, it may surprise its prey by curving its body and, bracing itself with its posteriorly positioned fins, launching a quick strike forward in the manner of a snake. It may also be able to close its gill slits and create negative pressure to suck prey into its mouth.[18] The many small, sharp, recurved teeth of the frilled shark are functionally similar to squid jigs and could easily snag the body or tentacles of a squid, particularly as they are rotated outwards when the jaws are protruded. Observations of captive frilled sharks swimming with their mouths open suggest that the small teeth, light against the dark mouth, may even fool squid into attacking and entangling themselves.[15]

The frilled shark is aplacental viviparous; the developing embryos are mainly nourished by yolk, though the difference in weight between the egg and the newborn indicates that the mother also provides additional nutrition via unknown means. Adult females have two functional ovaries and one functional uterus, on the right. Unsurprisingly, there is no defined breeding season for either sex, as this shark inhabits depths at which there is little to no seasonal influence.[17] A possible mating aggregation of 15 male and 19 female sharks has been recorded over a seamount on the Mid-Atlantic Ridge.[14] The litter size ranges from two to fifteen, with an average of six.[5] Females ovulate eggs into the uterus about once every two weeks; vitellogenesis (yolk formation) and the growth of new ovarian eggs halt during pregnancy, apparently due to insufficient space inside the body cavity.[17]

Newly ovulated eggs and early-stage embryos are enclosed in a thin, ellipsoid, golden-brown capsule. When the embryo is 3 cm (1.2 in) long, the head is pointed when seen from above or below, the jaws are barely developed, the external gills have begun to appear, and all the fins are present. The egg capsule is shed when the embryo grows to 6–8 cm (2.4–3.1 in) long, and is expelled from the female's body; at this time the embryo's external gills are fully developed.[17][25] The size of the yolk sac remains mostly constant until around an embryonic length of 40 cm (16 in), whereupon it begins to shrink, mostly or completely disappearing by an embryonic length of 50 cm (20 in). The embryonic growth rate averages 1.4 cm (0.55 in) per month, and therefore the entire gestation period may last three and a half years, far longer than any other vertebrate.[17][18] Newborn sharks measure 40–60 cm (16–24 in) long; males attain sexual maturity at 1.0–1.2 m (3.3–3.9 ft) long, and females at 1.3–1.5 m (4.3–4.9 ft) long.[1]

The frilled shark has seldom been encountered alive, and thus poses no danger to humans (though scientists have accidentally cut themselves examining its teeth).[12] On August 27, 2004, the first observation of this species in its natural habitat was made by the ROV Johnson Sea Link II, on the Blake Plateau off the southeastern United States.[13] On January 21, 2007, a Japanese fisherman discovered a 1.6 m (5.2 ft) long female alive at the surface, perhaps there because of illness or weakness from the warm water. It was brought to Awashima Marine Park in Shizuoka, where it died after a few hours.[26] Garman, and numerous authors since, have advanced the frilled shark as an explanation for sea serpent sightings. Because of the shark's modest size, some zoologists have posited the existence of a giant relative, particularly as larger Chlamydoselachus species are known from the fossil record.[3][4]

Small numbers of frilled sharks are caught incidentally by various deepwater commercial fisheries around the world, using trawls, gillnets, and longlines.[1] In particular, it is regularly taken in Suruga Bay in bottom gillnets meant for sea bream and gnomefish, and in midwater trawls meant for the shrimp Sergia lucens. Japanese fishermen regard it as a nuisance, as it damages the nets.[17] This shark is sometimes sold for meat or processed into fishmeal, but is not economically significant. Because of its very low reproductive rate and the continuing expansion of commercial fisheries into its habitat, the International Union for Conservation of Nature (IUCN) has previously listed it as Near Threatened, although the species was downlisted to Least Concern in 2016.[1]

In December 2014, trawler skipper David Guillot caught a 1.5 m (4.9 ft) frilled shark while "fishing in water more than 1 km (3,300 ft) deep near Lakes Entrance", in Victoria, Australia. The shark was taken to the Commonwealth Scientific and Industrial Research Organisation, where its identification was confirmed.[27]

Early in April 2017, during the filming of a Japanese television variety program in Tokyo Bay, a live specimen of the creature was captured.[28][29]

In August of 2017 a group of scientists caught a 1.5 m (4.9 ft) frilled shark in the waters off of Portimão, Portugal. The male shark was pulled from a depth of roughly 700 m (2,300 ft).[30][31] On November 14, 2017, researchers reported that another frilled shark was caught near the coast of Portugal.[32]


summary of mariama ba's so long a letter

So Long a Letter is written as a series of letters between the main character Ramatoulaye Fall and her best friend Aissatou following the sudden death of Ramatoulaye's husband Modou from a heart attack. The letters are written while Ramatoulaye participates in 'iddah, a four month and ten day mourning process that widows of the Muslim Senegalese culture must follow. Through the letters Ramatoulaye describes the emotions that flooded her during the first few days after her husband's death and speaks in detail about how he lost his life. She then discusses the life that she led with her husband, leading up to when Modou betrayed her by taking a second wife without her knowledge after 30 years of marriage. Ramatoulaye details to Aissatou how she dealt with this betrayal emotionally and how she grew throughout each event in her life.[2]

So Long a Letter

So Long a Letter (French: Une si longue lettre) is a semi-autobiographical epistolary novel originally written in French by the Senegalese writer Mariama Bâ.[1] Its theme is the condition of women in Western African society.

So Long a Letter, Mariama Bâ's first novel, is literally written as a long letter. As the novel begins, Ramatoulaye Fall is beginning a letter to her lifelong friend Aissatou Bâ. The occasion for writing is Ramatoulaye's recent widowhood. As she gives her friend the details of her husband's death, she recounts the major events in their lives.

The novel is often used in literature classes focusing on women's roles in post-colonial Africa. It won the first Noma Prize for Publishing in Africa in 1980.[1]

Senegal was home to many indigenous peoples during precolonial times. Around the 9th century AD Islamization spread throughout Senegal due to the expansive trade routes throughout Western Africa. Today, roughly 90 percent of Senegalese society follows Muslim religion while the remaining 10 percent follows forms of Christianity or mixed religions. Although many people follow Muslim religion, Arabic culture is not practiced in Senegal nor is Arabic spoken as the language. Much of their legal codes are from translated passages of the Qu'ran. French colonialism came to Senegal in the 1800s and enforced a separation of church and state. However many still abide by the Qu'ran's laws which shape ideas of gender roles, family life, marriage, and the patrilineal male dominated society.[3]

So Long a Letter deals with multiple themes, which includes the life of women in Senegal during the 1970s and 1980s, family and community life, Islam and polygamy, and death rituals.[4]


which film won the palme d'or prize at the 71st annual cannes film festival

The 71st annual Cannes Film Festival was held from 8 to 19 May 2018.[2] Australian actress Cate Blanchett acted as President of the Jury.[3] The Japanese film Shoplifters, directed by Hirokazu Kore-eda, won the Palme d'Or.[4]

2018 Cannes Film Festival

Asghar Farhadi's psychological thriller Everybody Knows, starring Javier Bardem, Penélope Cruz and Ricardo Darín, opened the festival and competed in the Main Competition section. It was the second Spanish-language film to open Cannes, following Pedro Almodóvar's Bad Education, which screened on the opening night of the 2004 festival.[5]

The official festival poster features Jean-Paul Belmondo and Anna Karina from Jean-Luc Godard's 1965 film Pierrot le Fou. It is the second time the festival poster was inspired by Godard's film after his 1963 film Contempt at the 2016 festival. According to festival's official statement, the poster is inspired by and paid tribute to the work of French photographer Georges Pierre.[1]

International Critics' Week

The following films were selected to compete for the Palme d'Or:[14][15][16]

The following films were selected to compete in the Un Certain Regard section:[14][15][16]

The following films were selected to be screened out of competition:[14][15][17][16][18]

The following films were selected be shown in the special screenings section:[14][15]

The following films were selected for the International Critics' Week section:[21][22]

The following films were selected to be screened in the Directors' Fortnight section:[23][24]

A ban on Netflix films in competition, which came about after the streaming giant refused to show them in French cinemas, has meant the issues of streaming and distribution have also been hot topics. The issue prompted Juror Ava DuVernay, who made 13th for Netflix, to make a plea for "flexibility of thought".[25]

In March and April 2018, weeks before general delegate Thierry Frémaux was set to unveil the official selection, reports suggested streaming service Netflix was to pull its already-selected films from premiering at the festival in retaliation for the barring of Netflix films from competing.[26][27] They were still allowed to premiere in other sections, and many reportedly opted for an Out of Competition berth. The films affected were Alfonso Cuarón's Roma, Morgan Neville's They'll Love Me When I'm Dead, Orson Welles' final film The Other Side of the Wind, Paul  Greengrass' Norway, and Jeremy Saulnier's Hold the Dark.

Ultimately, Netflix pulled all of their films from selection.[28] Notably, in the press conference announcement, FrÃ©maux commented that he wanted The Other Side of the Wind and had planned to screen it as a special screening with the Welles-related documentary They'll Love Me When I'm Dead.[29][30] He also noted that he had selected Roma for competition.

Danish film director Lars von Trier returned to Cannes with his film The House That Jack Built, after he was declared "persona non grata" at the 2011 festival.[31]

The chair of the jury Cate Blanchett has called for gender parity at the Cannes Film Festival, calling it "almost a gladiatorial sport". However, she concedes that there has been improvements and the change "won't happen overnight".[25]

During the festival, 82 female film professionals, led by Jury president Cate Blanchett and veteran director Agnès Varda, took part to a demonstration on the red carpet, demanding more equality between men and women in the film industry, notably the end of the pay gap.[32]

Un Certain Regard[34]

International Critics' Week[38]

Directors' Fortnight[39]

Prix FranÃ§ois Chalais[45]

Cannes Soundtrack Award[46]


what state do brooklyn and bailey live in

The Texas-based identical twins originally surfaced on YouTube in 2009 as models for their mother Mindy McKnightâ€™s DIY channel "Cute Girls Hairstyles", a video series of hair design tutorials.[2]

Brooklyn and Bailey McKnight

Brooklyn and Bailey McKnight (born December 31, 1999)[1] are American social media entertainers, musicians, and entrepreneurs. They are twin sisters.

In 2013 the twins launched their own YouTube channel, Brooklyn and Bailey, with a focus on teen interests, fashion, beauty, and "all things fun".[3]

In 2015 the twins were listed by Business Insider as one of "13 up-and-coming YouTube stars you should be following",[4] and their YouTube channel was nominated for a Streamy Award in the Fashion category.[5]

In November 2015, the sisters launched Squared, a YouTube channel and daily web series described by Variety as being "dedicated to all things twins".[2] Seven sets of twins from North America, the UK, and Australia contribute episodes to the series.[6]

In early 2017, Brooklyn and Bailey announced their entrance into the music industry.[7] The pair partnered with music producer Benny Cassette, and their first track, â€œDance Like Me", debuted March 3, 2017.[8] The track charted at #26 for most popular song and #12 for pop US song on iTunes. On April 28, 2017, the twins released their second single, "Simple Things". They released their third song "What We're Made Of" July 13, 2017. Brooklyn and Bailey had previously collaborated with Peter Hollens for a cover of Lennon and Maisy's "A Life That's Good" in August 2015.[9]

In 2017 the twins also launched their own merchandise line,[10] and they were on Forbes list of Top Influencers â€“ Kids.[11][12][13] In 2018 they were finalists in the YouTube Musician category for the 10th annual Shorty Awards.[14][15][16][17]

In April 2018, they both announced that they were going to attend Baylor University in Waco, Texas.[18]