Update at 11:16 a.m. PT Sunday: Blue Origin successfully launched and landed a New Shepard rocket around midday following some delays.

The world's richest man would like to remind you that SpaceX founder Elon Musk isn't the only billionaire hoping to send humans to space as soon as this year.

Jeff Bezos' Blue Origin plans to send its New Shepard rocket on its eighth test flight Sunday, and the commercial space company hopes to start putting humans aboard its vehicles by the end of the year.

The Amazon CEO tweeted Friday morning that preparations are underway for a Sunday launch from Blue Origin's Texas test facility as early as 8:30 a.m. Central Daylight Time.

Launch preparations are underway for New Shepard’s 8th test flight, as we continue our progress toward human spaceflight. Currently targeting Sunday 4/29 with launch window opening up at 830am CDT. Livestream info to come. @BlueOrigin #GradatimFerociter pic.twitter.com/zAYpAGWB8C — Jeff Bezos (@JeffBezos) April 27, 2018

The most recent test of New Shepard happened in December, when the rocket sent a dummy named "Mannequin Skywalker" to the edge of space inside the company's Crew Capsule 2.0. After the capsule separated from the rocket booster, the rocket returned to land not far from its launch point in much the same way SpaceX lands some of its Falcon 9 boosters. The passenger capsule then returned to Earth and a soft parachute landing.

There's been no word yet on any cleverly named dummies riding on Sunday's flight, but Bezos has promised the launch will be livestreamed.

While Bezos' Blue Origin and Musk's SpaceX have similar goals when it comes to using recyclable rockets, it wouldn't be quite right to call the two companies competitors -- at least not yet. SpaceX has dozens of government and commercial satellite launches under its belt, while Blue Origin is still largely in the testing phase for its planned space tourism flights.

The company is working on a larger rocket called New Glenn that could directly compete with SpaceX for commercial launch contracts, but it isn't expected to be ready until 2020.

But being far behind when it comes to building a client list and launch manifest hasn't stopped Bezos and Blue Origin from trolling SpaceX.

A New Shepard rocket was actually the first to touch the edge of space and then land back on Earth in one piece, beating Musk to the punch by about a month.

It's worth noting that SpaceX had an arguably more difficult task figuring out how to land a rocket returning from delivering a suborbital payload rather than just going straight up and down as in the case of New Shepard.

It now seems SpaceX and Blue Origin are again engaged in an undeclared race to be the first to launch humans aboard one of their crew capsules. (SpaceX has used its Dragon capsules for cargo missions to the International Space Station but has yet to send a person to space.)

Blue Origin Chief Executive Bob Smith said last week the company hopes to start launching people later this year, and Musk said in February that SpaceX plans to send a crew to orbit aboard a Dragon capsule in 2018.

Stay tuned. The billionaires' battle for space supremacy is just getting started.

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