Buzz Aldrin, the second person to walk on the moon, has endorsed former President Donald Trump's bid for the White House, a blow to Vice President Kamala Harris.

With early voting underway across the country and Election Day less than a week away, Trump and Harris, the Republican and Democratic presidential candidates, respectively, are making their final arguments to win voters' support.

“The presidency requires an understanding of human nature, clear judgment, determination, knowledge, understanding and calm under pressure that few can naturally handle or have the life experience to successfully address,” Aldrin said in a statement.

The former astronaut said the presidency requires a “sober analysis” of situations and the instinct to “lead with determination.”

“From the skies over Korea in air-to-air combat to navigating, landing and walking on the moon, I appreciate this kind of pressure,” Aldrin continued. “I know what it is like to have to make such decisions decisively, principled, resolutely and consistently. Training, experience and trust count.”

Polling data shows a razor-thin gap between the candidates, with Harris leading statewide with 49 percent of the vote to Trump's 48 percent The Economist's survey tracker.

Nate Silver's forecast shows Harris ahead in the polls by 0.9 points, with a 71 percent chance of winning the popular vote.

In his endorsement, Aldrin also expressed support for the creation of the US Space Force under the Trump administration.

“Under the first Trump administration, I was impressed to see human space exploration promoted and re-emerged as a high-profile policy. “Under President Trump’s first term, America experienced a revived interest in space,” he wrote.

“These are concrete achievements that align with my concerns and America’s policy priorities,” Aldrin continued.

The U.S. Space Force was established on December 20, 2019 by the National Defense Authorization Act as the sixth branch of the U.S. Armed Forces.

Its primary mission is to organize, train and equip military personnel to protect the interests of the United States and its allies in space. This includes protecting satellites, space assets and U.S. operations from threats from opposing nations.

Aldrin is a renowned astronaut and engineer best known for being the second person to walk on the moon. A graduate of the Massachusetts Institute of Technology, Aldrin served as a fighter pilot during the Korean War before joining NASA in 1963.

He made history as the lunar module pilot of the Apollo 11 mission, which successfully landed on the moon on July 20, 1969.

After Neil Armstrong, Aldrin was the second person to walk on the lunar surface, where he conducted experiments and took photographs during their groundbreaking moonwalk.

After his career at NASA, Aldrin continued to advocate for space exploration and wrote several books, including his autobiography Return to Earth and the science fiction novel Encounter with Tiber. He was also an outspoken supporter of future manned missions to Mars.

His contributions to space exploration have cemented his legacy as a key figure in the history of human spaceflight, and he has also shared his personal struggles with depression and alcoholism and used his platform to inspire others.