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What you need to know for 10/21/2017

Star Talk: Launched into history

Star Talk: Launched into history

Fifty years ago, an Atlas rocket launched John Glenn into space, where he became the first American
Star Talk: Launched into history
John Glenn and his wife, Annie, ride in a limousine with Vice President Lyndon Johnson during a parade in the astronaut’s honor in Washington on Feb. 26, 1962. Six days earlier, Glenn became the first American to orbit Earth.
Photographer: The Associated Press

Fifty years ago, an Atlas rocket launched John Glenn into space, where he became the first American to orbit Earth and the third to travel into space. His flight was the sixth of the Mercury series, the first space program of the United States.

In all, there were nine missions in the Mercury program. The first tested the Redstone rocket that was used for the first four Mercury flights. Ham, a chimpanzee, was the “astronaut” on the second flight and Alan Shepard became the first American in space on the third. Gus Grissom flew the fourth mission, which duplicated Shepard’s flight. On the fifth Mercury mission, another astro-chimp, Enos, became the test pilot for a new rocket, the Atlas, which would enable astronauts to circle Earth.

Mercury-Atlas 6 was the successful first attempt by NASA to place a human into Earth orbit. However, the Soviet Union had placed Yuri Gagarin, the first man to orbit the Earth — and to go into space — above the Earth almost a year before Glenn’s flight.

Glenn named his space capsule Friendship 7, the “7” referring to the original seven Mercury astronauts selected by NASA in 1959. Glenn was the only Marine in the group; the other six were from the Army or Navy.

The Flight

After the successful Mercury 5 flight carrying Enos in November 1961, NASA announced that Glenn would pilot America’s first manned orbital mission; fellow Mercury astronaut Scott Carpenter would be his backup.

Glenn’s Atlas rocket was delivered to Cape Canaveral at the end of November. This mission could not use a Redstone rocket, which had carried Shepard into space nine months earlier, because Shepard’s flight was suborbital — a journey that just arched up into space and then splashed down in the Atlantic Ocean 15 minutes later. To get into Earth orbit, Glenn would require a more powerful rocket. That was the Atlas, which held more fuel and could provide thrust for a longer time.

Originally, NASA had hoped to orbit an astronaut before the end of 1961, the same year as Gagarin’s flight. Regrettably, it was not to be; it quickly became apparent that not all the hardware would be ready, so the first launch date announced was for mid-January 1962.

However, weather delays and technical problems with the rocket pushed the launch date into February. Finally, on Feb. 20, 1962, after Glenn had waited in the Mercury space capsule for almost four hours, the Mercury-Atlas 6 rocket was “lit” and he was sent into space. Once there, he said the view was “tremendous.” As he zoomed around Earth at 17,500 miles per hour, he was given the “go” for seven orbits — but this also was not to be.

First orbit

During the first orbit of Friendship 7, all systems were working well. Glenn soared over Africa and noticed a dust storm taking place on the continent. Next, he saw his first sunset from orbit. He described it as beautiful, with brilliant orange and blue shades spread out on either side of the sun and the sky above very black.

After that, he passed over Australia, where he saw the city lights of Perth. He then prepared for his first orbital sunrise. As this occurred, Glenn noticed his now-famous “fireflies.” He described these fragments as “brilliant specks, floating around the outside of the capsule.” On the next Mercury mission, Carpenter identified the “fireflies” as frost flaking off the outside of the spacecraft.

As Glenn started his second orbit, ground controllers noticed that a sensor reading on the Mercury 6 capsule was indicating that its heat shield was loose. They did not inform Glenn of this, but he became suspicious when he was asked if he heard any rattling noises from the back of his ship. He did not. The situation continued to be monitored and the rest of the second orbit went well.

It was decided to bring Friendship 7 back to Earth on its third orbit. Mission control informed Glenn not to jettison the capsule’s retrorockets after use (the straps holding these rockets would provide additional support for the heat shield).

Re-entry fireball

He described the re-entry as a “real fireball” as the retrorockets disintegrated in the heat of re-entry into Earth’s atmosphere. It was later determined that the landing systems sensor had been faulty and the capsule’s heat shield was in fact secure.

Splashdown took place in the Atlantic Ocean almost five hours after liftoff. Following his flight, Glenn was grounded by President Kennedy because he had become an American icon and it was felt he could not be risked on another spaceflight. However, Glenn did go into space again. In 1998, he flew as a mission specialist on the 25th flight of the space shuttle Discovery and became the oldest person to fly in space.

Glenn, now 91, along with Carpenter, 86, are the only Mercury 7 astronauts still with us. Glenn’s Friendship 7 Mercury capsule is on display at the Smithsonian National Air and Space Museum in Washington.

February sky

Jupiter and Venus will remain impressively bright throughout the coming month. During that same time, the gap of sky between the two planets will significantly narrow as the two advance toward an eye-catching pairing in mid-March. Meanwhile, Mars will be rising during mid-evening, Saturn will rise before midnight and Mercury will be back in view at dusk for a few weeks starting the third week of February.

Venus, currently one of two evening “stars,” appears in the southwestern sky a half hour or so after sunset. The planet, already very bright, will reach its maximum brightness during the first week of February and hold that brightness for the month. Venus will also continue to set later, so that by leap day the planet will set as late as 9:30 p.m.

Jupiter, our other evening “star,” will spend February to the upper left of Venus. Giant Jupiter first comes into view in the south-southwest as the sky darkens. It will dim imperceptibly during February and will set in the west at 10:30 p.m. by month’s end — an hour-and-a-half earlier than its setting time now.

Tonight, the moon will be to the right of Jupiter and tomorrow evening will be at first quarter and positioned above Jupiter. When the moon is two days past full on Feb. 9, it will rise a few minutes after Mars and be to the right of the Red Planet. Two more days and the moon does the same in late evening with Saturn. Very early evening on Feb. 22, a lunar sliver is very low in the west to the right of Mercury. Three days later, a thicker lunar crescent will appear quite close to Venus. It will be a spectacular sight.

Richard Monda is an astronomer living in the Capital Region.

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