(Reuters) -Two moon landings in less than a week have once again turned the spotlight on space startups as NASA leans on private companies to send scientific payloads to the lunar surface at a lower cost before the U.S. sends astronauts there around 2027.

Intuitive Machines' second lunar lander, Athena, apparently landed on its side near the south pole of the moon on Thursday, rendering the mission "off-nominal". The firm's mission last year became the first U.S. touchdown on the lunar surface in more than half a century.

Thursday's mission came after a successful landing by Firefly Aerospace in its first attempt over the weekend.

Here are some firms working toward exploring the opportunities:

INTUITIVE MACHINES

Intuitive Machines, led by former NASA employees, has one more planned mission to deliver additional research tools to the lunar surface for NASA.

However, the company has delayed the mission, scheduled for next year, to wait for the deployment of its communications satellite.

The Texas-based company's Odysseus lander had a hard touchdown in its first mission last February. Still, the mission was deemed a success as payloads were able to execute their tasks.

FIREFLY AEROSPACE

The company, based in Cedar Park, Texas, succeeded in its first attempt to land on the moon with its uncrewed Blue Ghost spacecraft on Sunday, kicking off a two-week research mission.

Firefly, backed by AE Industrial Partners, has a $101 million contract for the Blue Ghost mission from NASA's Commercial Lunar Payload Services program.

It raised $175 million in a late-stage funding round led by RPM Ventures, at a more than $2 billion valuation, the company said last year.

SPACEX

Elon Musk's SpaceX - one of the world's most valuable startups with a valuation of about $350 billion - has in recent years led the private sector's efforts in the space industry with its reusable rockets and broadband satellites.

However, on Thursday, its eighth test launch of the Starship mega rocket, meant to take humans to Mars, exploded in space just minutes after launch from Texas, marking the second straight failure for the company this year.

The company's Starlink is a constellation of more than 7,000 satellites, according to a database created by astronomer Jonathan McDowell. The network provides broadband to parts of earth.

ROCKET LAB

Rocket Lab, founded in 2006 by New Zealander Peter Beck, is widely considered to be one of the more promising "New Space" companies as it is the most frequent private launcher of rockets after SpaceX.

The company provided Firefly with three high-efficiency solar panels, its MAX Flight and MAX Ground Data Software suites for the Blue Ghost mission.

Rocket Lab is currently developing a medium-lift rocket called Neutron to carry heavier payloads to space.

BLUE ORIGIN

Blue Origin, the aerospace company founded by billionaire Jeff Bezos, has been selected by NASA to develop its Blue Moon human landing system for the Artemis V mission at a total contract value of $3.4 billion.

Blue Origin plans to launch its uncrewed Mark 1 cargo lander to the Moon this year to test hardware. The Mark 1 can deliver about 3,000 kg of cargo in a single launch using the New Glenn rocket, which was successfully tested earlier this year.

The U.S. agency in 2023 also awarded Blue Origin $35 million to advance its Blue Alchemist technology to autonomously make solar cells and oxygen from moon dust and crushed rock.

The company also competes with British business tycoon Richard Branson's Virgin Galactic for space tourism. Last month, Blue Origin announced an all-female crew aboard its New Shepard rocket to the edge of space.

(Reporting by Akash Sriram in Bengaluru; Editing by Sriraj Kalluvila)