NASA's Mercury-Atlas 6 Friendship 7 mission created history in 1962 with a 4 hours, 55 minutes and 23 seconds flight

NASA's Mercury-Atlas 6 Friendship 7 mission sent astronaut John H. Glenn, Jr., into Earth orbit on February 20, 1962. Glenn became the first American to orbit Earth, making three circuits around the planet in a 4 hours, 55 minutes and 23 seconds flight.

NASA's Mercury-Atlas 6 Friendship 7 mission

Mercury-Atlas 6 was a crewed orbital spaceflight. John H. Glenn, Jr., was the sole crew member. The spacecraft was Friendship 7, also called Mercury Spacecraft No. 13. The launch vehicle was Atlas LV-3B, number 109-D. On February 20, 1962, Mercury-Atlas 6 was launched at 9:47:39 a.m. EST from Cape Canaveral Launch Complex 14, Florida.

How the launch was delayed?

The launch campaign started prior to February 20. The Mercury countdown began on January 27, when first of all and in two phases the flight crews performed the main spacecraft systems checks. There followed a 17.5-hour hold to allow the teams to make pyrotechnic checks and to perform electrical connections and peroxide system servicing. The countdown went to T-13 min when, because of bad weather, the countdown was canceled.

After the countdown was canceled, the mission teams decided they should replace the carbon dioxide absorber unit in the spacecraft. The peroxide system had to be drained and flushed to avoid any corrosion in the lines.

A check of the fuel tank revealed a leak in the inner bulkhead. Repairs on the bulkhead would take four to six days. The launch was postponed to February 13, then to February 14. The precount was resumed on February 14, 15, and 16, only to be canceled again each time by weather.

Finally, the launch was set for February 20. The flight safety review had been completed on February 15, and the spacecraft itself, which had arrived at the Cape Canaveral Air Force Station on August 27, 1961, had been checked out.

What happened during the February 20 countdown?

The countdown on February 20, involved a number of checkpoints and holds. The launch vehicle was switched to internal power at T-3 min. At T-35 sec, the spacecraft umbilical was ejected, and at T-0, the main engines were ignited. Liftoff came 4 sec later at 9:47:39 a.m. EST.

NASA mission objective and orbital flight

The objective of the flight was to put a man into orbit around the Earth, observe his reactions to the space environment, and return him safely to an area where he could be recovered.

The Atlas rocket sent Friendship 7 into orbit, and Glenn made three orbits around the Earth. Each orbit took about 88 min and 29 sec. The flight lasted 4 hr, 55 min, and 23 sec, and Glenn spent 4 hr, 48 min, and 27 sec in weightlessness.

Control system problem during the flight

During the flight, near the end of the first orbit, a control system problem developed. One of the yaw attitude control jets seemed to become clogged, affecting the automatic attitude control system. Glenn therefore had to switch over from the automatic system to the manual-electrical fly-by-wire system. The switch allowed him to maintain control of the spacecraft, and this problem became one of the main technical difficulties encountered during the flight.

The heat shield warning

Later in the flight, another problem developed. A sensor switch indicated that the clamp holding the heat shield had opened, which if the signal was accurate, could have left the heat shield vulnerable during the reentry.

The controllers, however, took the warning as a potential problem. They told Glenn to keep the spent retropack attached during the reentry as an added precaution in case the heat shield had somehow become detached.

How John Glenn returned to Earth?

Friendship 7 landed in the Atlantic Ocean about 800 mi southeast of Bermuda on 20 February 1962. The landing was recorded at 14:43:02 EST. The destroyers USS Noa was assigned the task of recovering the spacecraft.

Watchers aboard the Noa saw Friendship 7's main parachute at about 5,000 ft. The spacecraft was about five nautical miles away at the time. The Noa had the spacecraft aboard 21 min after the landing.

Glenn remained in the spacecraft during the recovery operation. The original plan was to have him exit through the top hatch. Glenn, however, was becoming uncomfortable from the heat inside the capsule, and he and the recovery team agreed that an easier exit would be best.