Russian cosmonauts Oleg Kononenko and Alexey Ovchinin have completed a spacewalk outside the International Space Station on Wednesday, May 29.

According to NASA, the spacewalk lasted 6 hours and 1 minute, starting at 11:42 a.m. EDT and ending at 5:43 p.m. The entire walk was broadcasted live by the space agency.

Cosmonauts Pay Tribute To An Icon In Space

Kononenko, who is the Expedition 59 commander on his fifth spacewalk, and Ovchinin, flight engineer on his first, took the opportunity to wish fellow cosmonaut Alexei Leonov a happy birthday from the vacuum of space.

Celebrating his 85th birthday on Thursday, May 30, Leonov made history as the first ever human being to walk in space. He left the Voskhod 2 mission spacecraft for a 12-minute spacewalk on March 18, 1965.

To honor Leonov, the two spacewalking Russian cosmonauts put signs on the back of their spacesuits. Kononenko's sign says "1st spacewalker," while Ovchinin's says, "Happy birthday, Alexei Arkhipovich," which is the cosmonaut icon's family name.

The pair also brought a framed picture of Leonov into space with them, dedicating the spacewalk especially to him.

"It just so happens we are performing a spacewalk the day before the birthday of Alexey Leonov, the first man to ever don a spacesuit and venture out of his spacecraft's airlock, taking a step into the starlit abyss, into the vastness of space," said Kononenko as they kicked off the spacewalk with birthday greetings for Leonov.

After about 30 minutes trying to get into position for this, Oleg Kononenko and Alexey Ovchinin send a birthday message to Alexei Leonov - the first man to walk in space. Leonov is 85 years old on Thursday. pic.twitter.com/OdA5Aj98ll — Chris B - NSF (@NASASpaceflight) May 29, 2019

Russian Duo Completed Tasks For ISS

After paying tribute to Leonov, the cosmonauts turned their attention to the list of tasks for the spacewalk, which included installing a handrail, retrieving science experiments, removing and jettisoning experiment hardware, and conducting maintenance work on the orbiting laboratory.

Six hours into the spacewalk, the duo wrapped up the spacewalk and headed back inside the ISS. Kononenko is slated to return to Earth on June 24 after a six-and-a-half-month stint in space. Then Ovchinin will take over as mission commander.

This latest spacewalk is the 217th to be completed for the support of the station assembly, maintenance, and upgrades.

Since the beginning of 2019, this is the fourth spacewalk outside the ISS.