Space exploration

CORRECTS TO NASDAQ, NOT NEW YORK STOCK EXCHANGE - In this image from video made available by NASA, astronaut Chris Cassidy, right, rings the opening bell of the Nasdaq Stock Exchange accompanied by fellow astronauts Robert L. Behnken, left, and Doug Hurley in the International Space Station on Tuesday, June 2, 2020. (NASA via AP)

In this image provided by NASA, a view of SpaceX's Crew Dragon spacecraft with NASA astronauts Douglas Hurley and Robert Behnken onboard is seen on monitors in firing room four of the Launch Control Center at NASA's Kennedy Space Center in Florida, as the spacecraft approaches the International Space Station for docking, Sunday, May 31, 2020. The Dragon capsule arrived Sunday morning, hours after a historic liftoff from Florida. (Joel Kowsky/NASA via AP)

A SpaceX Falcon 9, with NASA astronauts Doug Hurley and Bob Behnken in the Dragon crew capsule, lifts off from Pad 39-A at the Kennedy Space Center in Cape Canaveral, Fla., Saturday, May 30, 2020. For the first time in nearly a decade, astronauts blasted towards orbit aboard an American rocket from American soil, a first for a private company.(AP Photo/John Raoux)

Spectators watch from a bridge in Titusville, Fla. as SpaceX Falcon 9 lifts off with NASA astronauts Doug Hurley and Bob Behnken in the Dragon crew capsule, Saturday, May 30, 2020 from the Kennedy Space Center at Cape Canaveral, Fla. The two astronauts are on the SpaceX test flight to the International Space Station. For the first time in nearly a decade, astronauts blasted towards orbit aboard an American rocket from American soil, a first for a private company. (AP Photo/Charlie Riedel)

NASA Administrator Jim Bridenstine, left, and Kennedy Space Center Director Bob Cabana, right, walk toward the stage for a countdown clock briefing for the SpaceX Demo-2 mission Friday, May 29, 2020, at Kennedy Space Center in Cape Canaveral, Fla. The Falcon 9, with the Crew Dragon spacecraft on top of the rocket, is scheduled to liftoff from Launch Pad 39-A Saturday. Two astronauts will fly on the mission to the International Space Station. (AP Photo/David J. Phillip)

President Donald Trump gestures as he participates in a tour of NASA facilities before viewing the SpaceX Demonstration Mission 2 Launch at Kennedy Space Center, Wednesday, May 27, 2020, in Cape Canaveral, Fla. Marillyn Hewson, chief executive officer of Lockheed Martin, looks on at right. (AP Photo/Evan Vucci)

In this image made from video via NASA-TV, a SpaceX Falcon 9, with NASA astronauts Doug Hurley and Bob Behnken in the Dragon crew capsule, prepare to lift off from Pad 39-A at the Kennedy Space Center in Cape Canaveral, Fla., Wednesday, May 27, 2020. The two astronauts are on the SpaceX test flight to the International Space Station. (NASA via AP)

The SpaceX Falcon 9, with the Crew Dragon spacecraft on top of the rocket, sits on Launch Pad 39-A Monday, May 25, 2020, at Kennedy Space Center, Fla. Two astronauts will fly on the SpaceX Demo-2 mission to the International Space Station scheduled for launch on May 27. (AP Photo/David J. Phillip)

The SpaceX Falcon 9, with the Crew Dragon spacecraft on top of the rocket, sits on Launch Pad 39-A, Monday, May 25, 2020, at Kennedy Space Center, Fla. Two astronauts will fly on the SpaceX Demo-2 mission to the International Space Station scheduled for launch on May 27. (AP Photo/David J. Phillip)