Gravity

John Herschel Glenn, Jr.

First first American to orbit the Earth, and later, the oldest person to make a spaceflight.

( Born July 18, 1921) is a retired United States Marine Corps pilot, astronaut, and United States senator. He was a combat aviator in the Marine Corps, and now the only surviving member of the Mercury Seven; the elite U.S. military test pilots selected by NASA to operate the experimental Mercury spacecraft and become the first American astronauts.

On February 20, 1962, Glenn flew the Friendship 7 mission and became the first American to orbit the Earth and the fifth person in space, after cosmonauts Yuri Gagarin and Gherman Titov and the suborbital missions of fellow Mercury Seven astronauts Alan Shepard and Gus Grissom. In 1965, Glenn retired from the military and resigned from NASA so he could be eligible to stand for election to public office. As a member of the Democratic Party he was elected to represent Ohio in the U.S. Senate from 1974 to 1999.Glenn received a Congressional Space Medal of Honor in 1978, and the Presidential Medal of Freedom in 2012. He was inducted into the Astronaut Hall of Fame in 1990. On October 29, 1998, while still a sitting senator, he became the oldest person to fly in space, and the only one to fly in both the Mercury and Space Shuttle programs, when at age 77, he flew on Discovery (STS-95). With the death of Scott Carpenter on October 10, 2013, Glenn is the last surviving member of the Mercury Seven

Sigmund Werner Paul Jähn

First German in space ..

(Born 13 February 1937) is a German pilot, who became the first German to fly in space as part of the Soviet Union's Interkosmos programme.

Jähn was born in Morgenröthe-Rautenkranz, in the Vogtland district of Saxony, Germany. From 1943 to 1951 he
attended school in his hometown, and after school trained as a printer.

In 1955 he joined the East German Air
Force, where he became a pilot and military scientist. From 1966 until 1970
he studied at the Gagarin Air Force Academy in Monino, in the Soviet Union, and afterwards worked in the
administration of the East German air force, responsible for pilot education and
flight safety.Jähn was awarded the title Hero of the Soviet Union on 3 September 1978.In 1983 he received a doctorate in physics at the Zentralinstitut für Physik der Erde (de) in Potsdam, specialising in remote sensing of the earth.

In 1976, Jähn was selected with his backup Eberhard Köllner for the Interkosmos programme. He trained in Star City near Moscow for the next two years, and flew on board Soyuz 31 (launched 26 August 1978) to the Soviet space station Salyut 6, and returned on Soyuz 29, landing on 3 September 1978. He spent 7 days, 20 hours, and 49 minutes in space.During and after the flight, he and the socialist authorities of the GDR pronounced him "the first German cosmonaut", which was remarkable, as in those days .the East German state normally stressed that their people were "GDR citizens", to distinguish themselves from West Germany.

Chiaki Mukai

First Japanese Woman in space .

(Born on May 6, 1952, Tatebayashi, Gunma, Japan) is a Japanese doctor, and JAXA astronaut.She was the first Japanese woman in space, and was the first Japanese citizen to have two spaceflights.^[Both were Space Shuttle missions; her first was STS-65 aboard Space Shuttle Columbia in July 1994, which was a Spacelab mission. Her second spaceflight was STS-95 aboard Space Shuttle Discovery in 1998. In total she has spent 23 days in space.

Mukai was selected to be an astronaut by Japanese national space agency NASDA (now called JAXA) in 1985. Prior to this, she was an assistant professor in the Department of Cardiovascular Surgery in Keio University, the oldest university in Japan.

In 1985, Mukai was selected as one of three Japanese Payload Specialist candidates for the First Material Processing Test (Spacelab-J) which flew aboard STS-47. She also served as a back-up payload specialist for the Neurolab (STS-90) mission. Mukai has logged over 566 hours in space. She flew aboard STS-65 in 1994 and STS-95 in 1998. She is the first Japanese woman to fly in space, and the first Japanese citizen to fly twice.As a NASDA astronaut, she was a visiting scientist at the Division of Cardiovascular Physiology, Space Biomedical Research Institute, NASA Johnson Space Center, from 1987 to 1988. Mukai has remained a Research Instructor of the Department of Surgery, Baylor College of Medicine, Houston, Texas, since 1992. From 1992 to 1998 she was a visiting associate professor of the Department of Surgery, Keio University School of Medicine, Tokyo, and in 1999 was promoted to a visiting professor of the university.Mukai was assigned the deputy mission scientist for STS-107. In that capacity she coordinated science operations for this science mission. In 2009 Mukai was a visiting lecturer at the International Space University

Rodolfo Neri Vela

First Maxican in space

(Born 19 February 1952) is a Mexican scientist and astronaut who flew aboard a NASA Space Shuttle mission in the year 1985.^[1] He is the first and only Mexican, and the second Latin-American to have traveled to space.Neri received a bachelor's degree in mechanical and electrical engineering, National Autonomous University of Mexico (UNAM) 1975, and received a master's degree in science, specialized in telecommunications systems, in 1976 from the University of Essex, England. Neri then received a doctorate degree in electromagnetic radiation from the University of Birmingham in 1979, and performed one year of postdoctoral research in waveguides at the University of Birmingham.Neri was a Payload Specialist aboard the STS-61-B Atlantis mission, from (November 26 to December 3, 1985).STS-61B launched at night from Kennedy Space Center, Florida, and returned to land at Edwards Air Force Base, California. During the mission the crew deployed the MORELOS-B, AUSSATT II, and SATCOM K-2 communications satellites, conducted two six-hour spacewalks to monstrate space station construction techniques with the EASE/ACCESS experiments, operated the Continuous Flow
Electrophoresis (CRFES) experiment for McDonell Douglas and a Getaway Special (GAS) container for Telesat, Canada, conducted several Mexican Payload Specialists Experiments for the Mexican government, and tested the Orbiter Experiments Digital Autopilot (OEX DAP). At mission conclusion, Neri had traveled 2.4 million miles (3.8 million km) in 108 Earth orbits, and logged over 165 hours in space

Newton's Theory of Gravitation :

In 1687, English mathematician Sir Isaac Newton published Principia, which hypothesizes the inverse-square law of universal gravitation. In his own words, “I deduced that the forces which keep the planets in their orbs must [be] reciprocally as the squares of their distances from the centers about which they revolve: and thereby compared the force requisite to keep the Moon in her Orb with the force of gravity at the surface of the Earth; and found them answer pretty nearly.”

Newton's theory enjoyed its greatest success when it was used to predict the existence of Neptune based on motions of Uranus that could not be accounted for by the actions of the other planets. Calculations by both John Couch Adams and Urbain Le Verrier predicted the general position of the planet, and Le Verrier's calculations are what led Johann Gottfried Galle to the discovery of Neptune.

A discrepancy in Mercury's orbit pointed out flaws in Newton's theory. By the end of the 19th century, it was known that its orbit showed slight perturbations that could not be accounted for entirely under Newton's theory, but all searches for another perturbing body (such as a planet orbiting the Sun even closer than Mercury) had been fruitless. The issue was resolved in 1915 by Albert Einstein's new theory of general relativity, which accounted for the small discrepancy in Mercury's orbit.

Although Newton's theory has been superseded, most modern non-relativistic gravitational calculations are still made using Newton's theory because it is a much simpler theory to work with than general relativity, and gives sufficiently accurate results for most applications involving sufficiently small masses, speeds and Gravitational force .

Gravitational Force:

Law of Universal Gravitation:

Every particle attracts every other particle with a force that is proportional to the mass of the particles and inversely proportional to the square of the distance between them.

F directly propotional to mM/d2 .

The sign means “proportional to.” To make an equation out of the above situation, insert a quantity called the universal constant of gravitation,G.
G 6.67 1011 Nm2/kg2

Now the magnitude of this gravitational force can be represented as Force = ( universal constant of gravitation)2 (1mass) (mass2 )/ (distance)2

F = GmM/d2

Like all other forces, the gravitational force of attraction between two objects is measured in newtons.

SPACE HERO'S