The first astronauts launched by Elon Musk's SpaceX company departed the International Space Station on Saturday night for the final and most important part of their test flight: returning to Earth with a rare splashdown.

NASA's Doug Hurley and Bob Behnken bid farewell to the three men left behind as their SpaceX Dragon capsule undocked and headed toward a Sunday afternoon descent by parachute into the Gulf of Mexico.

Despite Tropical Storm Isaias' surge toward Florida's Atlantic shore, NASA said the weather looked favorable off the coast of Pensacola on the extreme opposite side of the state.

It will be the first splashdown for astronauts in 45 years. The last time was following the joint U.S.-Soviet mission in 1975 known as Apollo-Soyuz.

Space station commander Chris Cassidy rang the ship's bell as Dragon pulled away, 267 miles (430 kilometers) above Johannesburg, South Africa. Within a few minutes, all that could be seen of the capsule was a pair of flashing lights against the black void of space.

"It's been a great two months, and we appreciate all you've done as a crew to help us prove out Dragon on its maiden flight," Hurley radioed to the space station.

"Safe travels," Cassidy replied, "and have a successful landing."

The astronauts' homecoming will cap a mission that ended a prolonged launch drought in the U.S., which has relied on Russian rockets to ferry astronauts to the space station since the end of the shuttle era.

In launching Hurley and Behnken from NASA's Kennedy Space Center on May 30, SpaceX became the first private company to send people into orbit. Now SpaceX is on the verge of becoming the first company to bring people back from orbit.

"The hardest part was getting us launched, but the most important is bringing us home," Behnken said several hours before strapping into the Dragon.

A successful splashdown, Behnken said, will bring U.S.-crew launching capability "full circle."

At a farewell ceremony earlier in the day, Cassidy, who will remain on board with two Russians until October, presented Hurley with the small U.S. flag left behind by the previous astronauts to launch to the space station from U.S. soil. Hurley was the pilot of that final shuttle mission in July 2011.

The flag — which also flew on the first shuttle flight in 1981 — became a prize for the company that launched astronauts first.

SpaceX easily beat Boeing, which isn't expected to launch its first crew until next year and will land in the U.S. Southwest. The flag has one more flight after this one: to the moon on NASA's Artemis program in the next few years.

"We're a little sad to see them go," Cassidy said, "but very excited for what it means to our international space program to add this capability" of commercial crew capsules. The next SpaceX crew flight is targeted for the end of September.

Hurley and Behnken also are bringing back a sparkly blue and purple dinosaur named Tremor. Their young sons chose the toy to accompany their fathers on the historic mission.

NASA has launched its new Mars rover, Perseverance, on a six-month journey to the Red Planet as part of an ambitious, long-range project to bring the first Martian rock samples back to Earth to be analysed for evidence of ancient life, reports AP.

The biggest, most sophisticated Mars rover ever built — a car-size vehicle bristling with cameras, microphones, drills and lasers — blasted off on Thursday morning.

NASA’s Perseverance rode a Atlas V rocket into a clear morning sky in the world’s third and final Mars launch of the summer.

NASA’s science mission chief, Thomas Zurbuchen, pronounced the launch the start of “humanity’s first round trip to another planet.”

“There’s a reason we call the robot Perseverance. Because going to Mars is hard,” NASA Administrator Jim Bridenstine said just before liftoff. “In this case, it’s harder than ever before because we’re doing it in the midst of a pandemic.”

The overall cost has been estimated more than $8 billion.

The plutonium-powered, six-wheeled rover will drill down and collect tiny geological specimens that will be brought home in about 2031 in a sort of interplanetary relay race involving multiple spacecraft and countries.

China and the United Arab Emirates got a head start last week, but all three missions should reach their destination in February after a journey of seven months and 300 million miles (480 million kilometers).

The US, the only country to safely put a spacecraft on Mars, is seeking its ninth successful landing on the planet, which has proven to be the Bermuda Triangle of space exploration, with more than half of the world's missions there burning up, crashing or otherwise ending in failure.

China is sending both a rover an orbiter. The UAE, a newcomer to outer space, has an orbiter en route.

It’s the biggest stampede to Mars in spacefaring history.

The opportunity to fly between Earth and Mars comes around only once every 26 months when the planets are on the same side of the sun and about as close as they can get.

Launch controllers wore masks and sat spaced apart at the Cape Canaveral control center because of the coronavirus outbreak, which kept hundreds of scientists and other team members away from Perseverance’s liftoff.

About an hour into the flight, controllers applauded, pumped their fists and exchanged air hugs and pantomimed high-fives when the rocket flawlessly broke out of orbit around the Earth and began hurtling toward Mars.

The launch went off on time at 7:50am despite a 4.2-magnitude earthquake 20 minutes before liftoff that shook the Jet Propulsion Laboratory.

Perseverance will aim for treacherous unexplored territory: Jezero Crater, riddled with boulders, cliffs, dunes and possibly rocks bearing the chemical signature of microbes from what was once a lake more than 3 billion years ago.

The rover will store half-ounce (15-gram) rock samples in dozens of super-sterilized titanium tubes.

It also will release a mini helicopter that will attempt the first powered flight on another planet, and test out other technology to prepare the way for future astronauts.

That includes equipment for extracting oxygen from Mars' thin carbon-dioxide atmosphere.

Two other NASA landers are also operating on Mars: 2018′s InSight and 2012′s Curiosity rover. Six other spacecraft are exploring the planet from orbit: three from the US, two from Europe and one from India.

An international research group, led by Israeli experts, claimed to have successfully tested a drug for children with autism that was originally developed for Alzheimer's disease.

Tel Aviv University (TAU) disclosed the information on Tuesday, reports Xinhua.

TAU researchers and their colleagues from the Czech Republic, Greece, Belgium and Croatia tested the experimental drug called NAP.

They published their study in the journal Translational Psychiatry.

The drug may help children with ADNP syndrome, one of the 10 most common genetic syndromes on the autism spectrum and characterised by mental impairment.

This syndrome is caused by a mutation in the ADNP gene, leading to a deficiency and malfunctioning of the ADNP protein which is essential for brain development.

The team found NAP effective in treating nerve cells in a model of ADNP syndrome, as damaged nerve-like cells returned to normal function after being treated.

Researchers said the results show that treatment with the experimental drug will aid cognitive improvement in autistic children, and will enhance their memory and learning skills.

Israeli researchers have invented a method to utilize watermelons for fuel production, according to the Israeli news website Ynet.

Watermelons residues can be used to produce ethanol, a biological alternative fuel for vehicles, found a new study conducted by the University of Haifa (Oranim), reports Xinhua.

The researchers produced ethanol from an Israeli watermelon strain, grown only for its seeds, as part of the nut industry.

The red (flesh) and green (rind) parts, which together make up 97 percent of the watermelon's weight, are thrown in the fields as waste that remains unused.

During the harvest period, the researchers collected dozens of watermelons of the seed strain and fermented their juice into ethanol.

According to the researchers, bioethanol, and biofuels in general, reduces dependence on fossil fuels such as coal, natural gas and oil whose reserves are dwindling, and using them generates widespread greenhouse gas emissions.

Ethanol is also the main ingredient of medicinal disinfectants, such as hand sanitizers, so this development could also be useful in the current coronavirus period.

The researchers also found that watermelon waste could be used to produce lycopene, a dietary supplement sold as an antioxidant.

In a bold attempt to join the United States in successfully landing a spacecraft on the red planet, China launched its most ambitious Mars Tianwen-1 mission yet on Thursday.

Tianwen-1 was launched on a Long March-5 carrier rocket from Hainan Island, a resort province off the south coast of the mainland, state media said.

Livestreams showed a successful liftoff, with rockets blazing orange and the spacecraft heading upward across clear blue skies, reports AP.

Hundreds of space enthusiasts cried out excitedly on a beach across the bay from the launch site.

It marked the second flight to Mars this week, after a United Arab Emirates orbiter blasted off on a rocket from Japan on Monday. And the U.S. is aiming to launch Perseverance, its most sophisticated Mars rover ever, from Cape Canaveral, Florida, next week.

China’s tandem spacecraft — with both an orbiter and a rover — will take seven months to reach Mars, like the others. If all goes well, Tianwen-1, or “quest for heavenly truth,” will look for underground water, if it’s present, as well as evidence of possible ancient life.

This isn’t China’s first attempt at Mars. In 2011, a Chinese orbiter accompanying a Russian mission was lost when the spacecraft failed to get out of Earth’s orbit after launching from Kazakhstan, eventually burning up in the atmosphere.

This time, China is going at it alone. It also is fast-tracking, launching an orbiter and rover on the same mission instead of stringing them out.

China’s secretive space program has developed rapidly in recent decades. Yang Liwei became the first Chinese astronaut in 2003, and last year, Chang’e-4 became the first spacecraft from any country to land on the far side of the moon.

Conquering Mars would put China in an elite club.

“There is a whole lot of prestige riding on this,” said Dean Cheng, an expert on Chinese aerospace programs at the Heritage Foundation in Washington.

Landing on Mars is notoriously difficult. Only the U.S. has successfully landed a spacecraft on Martian soil, doing it eight times since 1976.

NASA's InSight and Curiosity rovers still operate today. Six other spacecraft are exploring Mars from orbit: three American, two European and one from India.

Unlike the two other Mars missions launching this month, China has tightly controlled information about the program — even withholding any name for its rover. National security concerns led the U.S. to curb cooperation between NASA and China's space program.

In an article published earlier this month in Nature Astronomy, mission chief engineer Wan Weixing said Tianwen-1 would slip into orbit around Mars in February and look for a landing site on Utopia Planitia — a plain where NASA has detected possible evidence of underground ice. Wan died in May from cancer.

The landing would then be attempted in April or May, according to the article. If all goes well, the 240-kilogram (530-pound) golf cart-sized, solar-powered rover is expected to operate for about three months, and the orbiter for two years.

Though small compared to America's hulking, car-sized 1,025-kilogram (2,260-pound) Perseverance, it's almost twice as big as the two rovers China has sent to the moon in 2013 and 2019. Perseverance is expected to operate for at least two years.

This Mars-launching season — which occurs every 26 months when Earth and Mars are at their closest — is especially busy.

The UAE spacecraft Amal, or Hope, which will orbit Mars but not land, is the Arab world’s first interplanetary mission. NASA's Perseverance rover is up next.

While China is joining the U.S., Russia and Europe in creating a satellite-based global navigation system, experts say it isn’t trying to overtake the U.S. lead in space exploration.

Instead, Cheng of the Heritage Foundation said China is in a “slow race” with Japan and India to establish itself as Asia’s space power.