The news of the iconic astronaut Neil Armstrong's death Saturday plunged American astronauts and spaceflyers around the world into mourning, with some expressing their sadness on Twitter.

Armstrong, the first man to walk on the moon and commander of NASA's Apollo 11 lunar landing mission, died at age 82 due to complications from recent heart surgery, his family said. Armstrong had heart bypass surgery earlier this month to clear blocked arteries.

Many astronauts with NASA and other space agencies cited Armstrong as a major inspiration in their lives in their Twitter messages. Others reflected on the legendary astronaut's modesty, despite his global fame.

"I know I am joined by millions of others in mourning Neil's passing — a true American hero and the best pilot I ever knew," wrote Apollo 11 astronaut Buzz Aldrin, who walked with Armstrong on the moon on July 20, 1969, in his Twitter post. He writes as @TheRealBuzz.


Several active and former NASA astronauts wrote that Armstrong inspired them to pursue dreams of flying in space.

"I am deeply saddened by the passing of Neil Armstrong," wrote former astronaut Leroy Chiao (@AstroDude), four-time spaceflyer and commander the International Space Station. "He was my childhood hero, who inspired me to become an astronaut myself." [Photos: Neil Armstrong – American Icon Remembered]

Former shuttle astronaut Mae Jemison, the first African-American woman to fly in space, agreed.

"As young girl watching #NeilArmstrong step on the moon, the stars came a little bit closer & my world & expectations quite a bit larger," Jemison wrote as ‏@maejemison.

Christopher Ferguson, the commander of NASA's last space shuttle mission (STS-135 in July 2011), was touched by Armstrong's modest demeanor despite his great feats in space.

"Today we lost a legend," Ferguson wrote Saturday as @AstroFerg." Neil was a source of personal inspiration and a humble and unassuming American hero."

But Armstrong was more than just an American icon. His legacy reached out across the entire world, as astronauts from Japan, Canada and Europe pointed out.

"RIP #NeilArmstrong, the 1st moonwalker. He inspired me to fly high," wrote astronaut Soichi Noguchi of the Japan Aerospace Exploration Agency (@Astro_Soichi), who included a photo of the moon in one of his two posts. " Salute to #NeilArmstrong, the 1st moonwalker. He inspired me deeply, long before I become spacewalker."

Canadian astronaut Chris Hadfield, who is currently training to command the International Space Station's Expedition 35 crew, cited Armstrong as an inspiration to all to excel.

"Neil Armstrong is one of my heroes. He inspired and challenged us all to work at the edges of what's possible. A life well-lived. RIP Neil," Hadfield wrote as @Cmdr_Hadfield.

Here are more astronaut reflections via Twitter mourning the death of Neil Armstrong:

NASA astronaut Ron Garan (‏@Astro_Ron)

Honor Neil Armstrong's example of service accomplishment + modesty Next time UC the moon think of Neil + #WinkAtTheMoon

European Space Agency astronaut Christer Fuglesang, of Sweden (@CFuglesang)

I'm sad. Neil Armstrong, 1st on Moon, incredible astronaut, fantastic person has passed away. I was very impressed the few times I met him.

NASA astronaut Leland Melvin (@AstroFlow)

Rest In Peace CDR Armstrong.

ESA astronaut Samantha Cristoforetti, of Italy (@AstroSamantha)

I'm grateful for this recent, one-hour interview w/ #NeilArmstrong. A man w/ so much to teach! http://thebottomline.cpaaustralia.com.au/

NASA astronaut Mike Foreman (@foreman_mike)

Definitely a sad day. He was a great American hero.

NASA astronaut Dorothy Lindenburger ‏(@AstroDot)

The astronaut family lost many this year, but each member contributed and lived so fully that ALL of the world has gained.

NASA astronaut Nicole Stott (‏@Astro_Nicole)

Neil Armstrong -his 1 small step will inspire generations to come. "the dream remains -there are places to go beyond belief."