The Atlas V rocket carrying Boeing's CST-100 Starliner capsule is seen, after the launch to the International Space Station was delayed for a do-over test flight in Cape Canaveral, Florida, U.S. August 4, 2021. REUTERS/Joe Skipper

The Atlas V rocket carrying Boeing's CST-100 Starliner capsule is seen, after the launch to the International Space Station was delayed for a do-over test flight in Cape Canaveral, Florida, U.S. August 4, 2021. REUTERS/Joe Skipper

Crew members inspect a partially inflated hot air balloon at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A crew member inspects a partially inflated hot air balloon at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A crew member inspects a partially inflated hot air balloon at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Crew members inflate a hot air balloon at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A crew member inspects a partially inflated hot air balloon at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Hot air balloons launch during a mass take off at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A hot air balloon is seen flying at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A hot air balloon is seen flying at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Hot air balloons launch during a mass take off at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A hot air balloon is seen flying at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Crew members test a burner at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Hot air balloons launch during a mass take off at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Hot air balloons launch during a mass take off at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Hot air balloons launch during a mass take off at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

Hot air balloons launch during a mass take off at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A hot air balloon is seen flying at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls TPX IMAGES OF THE DAY

Crew members inflate a hot air balloon at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls

A crew member inspects a partially inflated hot air balloon at the Bristol International Balloon Fiesta in Bristol, Britain, August 4, 2021. REUTERS/Henry Nicholls TPX IMAGES OF THE DAY

An Atlas V rocket carrying Boeing's CST-100 Starliner capsule stands on the pad after the planned launch to the International Space Station was postponed, in Cape Canaveral, Florida, U.S. August 3, 2021. REUTERS/Steve Nesius

An Atlas V rocket carrying Boeing's CST-100 Starliner capsule stands on the pad after the planned launch to the International Space Station was postponed, in Cape Canaveral, Florida, U.S. August 3, 2021. REUTERS/Steve Nesius

An Atlas V rocket carrying Boeing's CST-100 Starliner capsule is prepared for launch to the International Space Station for a do-over test flight in Cape Canaveral, Florida, U.S. August 2, 2021. REUTERS/Steve Nesius

An Atlas V rocket carrying Boeing's CST-100 Starliner capsule is prepared for launch to the International Space Station for a do-over test flight in Cape Canaveral, Florida, U.S. August 2, 2021. REUTERS/Steve Nesius

An Atlas V rocket carrying Boeing's CST-100 Starliner capsule is prepared for launch to the International Space Station for a do-over test flight in Cape Canaveral, Florida, U.S. August 2, 2021. REUTERS/Steve Nesius

Karen Tyler embraces her son Jonathan who arrived from the U.S., at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A worker sanitises a barrier at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Karen Tyler embraces her son Jonathan who arrived from the U.S., at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A worker sanitises a sign at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A man awaiting a friend holds a sign at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A man awaiting a friend holds a sign at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

People meeting family members from the U.S. embrace at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

People meeting family members from Charlotte in the U.S. embrace at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

People meeting family members from Charlotte in the U.S. embrace at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A man embraces his granddaughter after she arrived with family from Charlotte in the U.S., at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Passengers walk through the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Claire Frohlich embraces her daughter who returned from the U.S., in the International arrivals area of Terminal 5 at London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A British Airways captain walks through the International arrivals area of Terminal 5 at London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Women embrace at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Claire Frohlich embraces her daughter who returned from the U.S., in the International arrivals area of Terminal 5 at London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A passenger stands next to a COVID-19 testing centre sign in the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Sue Blake embraces her grandson Elliot who returned with family from the U.S., at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

A British Airways flight crew walk through the International arrivals area of Terminal 5 at London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Claire and Steven Frohlich embrace their daughter who returned from the U.S., in the International arrivals area of Terminal 5 at London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

John Holland-Kaye, CEO of Heathrow Airport talks during an interview with journalists at the International arrivals area of Terminal 5 in London's Heathrow Airport, Britain, August 2, 2021. REUTERS/Peter Nicholls

Marine One with U.S. President Joe Biden aboard departs the White House in Washington, U.S., for a weekend in Camp David, July 30, 2021. REUTERS/Evelyn Hockstein

The Atlas V rocket carrying Boeing's CST-100 Starliner capsule is seen after the launch to the International Space Station was delayed for a do-over test flight in Cape Canaveral, Florida, U.S. July 30, 2021. REUTERS/Joe Skipper

The Atlas V rocket carrying Boeing's CST-100 Starliner capsule is seen after the launch to the International Space Station was delayed for a do-over test flight in Cape Canaveral, Florida, U.S. July 30, 2021. REUTERS/Joe Skipper

Atlas V rocket carrying Boeing's CST-100 Starliner capsule is prepared for launch to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

Atlas V rocket carrying Boeing's CST-100 Starliner capsule is prepared for launch to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

Atlas V rocket carrying Boeing's CST-100 Starliner capsule is prepared for launch to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

NASA Administrator Bill Nelson speaks prior to the launch of an Atlas V rocket carrying Boeing's CST-100 Starliner capsule to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

NASA Administrator Bill Nelson speaks prior to the launch of an Atlas V rocket carrying Boeing's CST-100 Starliner capsule to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

NASA Administrator Bill Nelson speaks prior to the launch of an Atlas V rocket carrying Boeing's CST-100 Starliner capsule to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

NASA Administrator Bill Nelson reacts at a press conference prior to the launch of an Atlas V rocket carrying Boeing's CST-100 Starliner capsule to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

NASA Administrator Bill Nelson speaks prior to the launch of an Atlas V rocket carrying Boeing's CST-100 Starliner capsule to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

NASA Deputy Administrator Pam Melroy speaks prior to the launch of an Atlas V rocket carrying Boeing's CST-100 Starliner capsule to the International Space Station in a do-over test flight at Kennedy Space Center in Cape Canaveral, Florida, U.S. July 29, 2021. REUTERS/Joe Skipper

Seabird, a plane operated by German NGO Sea-Watch, is seen from the migrant rescue ship Sea-Watch 3 as it patrols the search and rescue zone in international waters off the coast of Libya, in the western Mediterranean Sea, July 28, 2021. REUTERS/Darrin Zammit Lupi

Seabird, a plane operated by German NGO Sea-Watch, is seen from the migrant rescue ship Sea-Watch 3 as it patrols the search and rescue zone in international waters off the coast of Libya, in the western Mediterranean Sea, July 28, 2021. REUTERS/Darrin Zammit Lupi

Mil Mi-28 military helicopters perform during the MAKS 2021 air show in Zhukovsky, outside Moscow, Russia, July 25, 2021. REUTERS/Tatyana Makeyeva