NASA and rocket maker United Launch Alliance are making preparations for the launch of the space agency’s Mars 2020 Perseverance Rover.

The launch window for the spacecraft that will carry the Perseverance rover to Mars opens on July 30 and closes on Aug. 15, 2020. The rover will launch atop a United Launch Alliance Atlas V rocket from Cape Canaveral Air Force Station in Florida.

“We’re testing,” ULA CEO Tory Bruno told Fox News Wednesday. “There will be testing, testing and more testing for the next several days.”

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Bruno explained that the rocket and the spacecraft are in the giant Vertical Integration Facility (VIF) at Cape Canaveral.

“It allows us to build the vehicle up on its vertical orientation,” he said. The spacecraft and the rover are already on top of the Atlas V rocket, Bruno explained, safely beneath the payload fairing that will protect them during launch.

This illustration depicts NASA's Perseverance rover operating on the surface of Mars.

This illustration depicts NASA's Perseverance rover operating on the surface of Mars. (NASA/JPL-Caltech)

When all the preparations at the Vehicle Integration Facility are completed, the rocket and spacecraft will be rolled along a path to Cape Canaveral Air Force Station’s Launch Complex 41.

On Wednesday, NASA announced that the rover mission had passed its Flight Readiness Review, a key milestone during launch preparations.

“Our deepest thanks go to the many teams who have worked so hard to get Perseverance ready to fly during these challenging times,” said NASA Administrator Jim Bridenstine in a statement. “This mission is emblematic of our nation’s spirit of meeting problems head-on and finding solutions together. The incredible science Perseverance will enable and the bold human missions it will help make possible are going to be inspirations for us all.”

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A Launch Readiness Review is scheduled for July 27. In its statement, NASA describes the Launch Readiness Review as “the last significant checkup before the mission receives final approval to proceed with launch.”

The nose cone containing NASA's Mars 2020 Perseverance rover is maneuvered into place atop its Atlas V rocket. The image was taken at Cape Canaveral Air Force Station in Florida on July 7, 2020.

The nose cone containing NASA's Mars 2020 Perseverance rover is maneuvered into place atop its Atlas V rocket. The image was taken at Cape Canaveral Air Force Station in Florida on July 7, 2020. (Credits: NASA/KSC)

The launch window, which opens at 7:50 a.m. ET on July 30, has been planned for when Earth and Mars are in perfect alignment for the epic mission to the Red Planet.

“It takes less power to travel to Mars at this time, compared to other times when Earth and Mars are in different positions in their orbits,” explains NASA on its website.

This opportunity only presents itself once every two years, Bruno explained.

“Earth and Mars have to be aligned in order to go there,” he said.

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On July 30 the launch window will be open for two hours. If the launch doesn’t happen on that day, there will be other two-hour launch opportunities on the following days.

“The start time will move a little bit every day,” Bruno explained, noting that the daily window starts to get a bit shorter on Aug. 3. “On the 15th [of August] it will be 30 minutes,” he added.

“We’re working with NASA to see if we could squeeze out another day or two if we need to,” Bruno said.

Initially, the launch window was scheduled to open on July 17, although this was pushed back to July 20, July 22 and then July 30. This gave experts time to resolve, respectively, a crane malfunction in the VIF, a “contamination concern” in the ground support lines in NASA’s Payload Hazardous Servicing Facility and a liquid oxygen sensor line that presented “off-nominal data” during what is known as a “Wet” Dress Rehearsal for the launch.

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“We have to take these precautions,” Bruno said.

Coronavirus played no part in the delays, the ULA CEO explained, noting that the Mars rover will be the company’s third space launch since the start of the pandemic.

Mars is looming large for a number of other countries. Early Thursday, for example, China successfully launched its own Tianwen-1 mission to land a rover on Mars.

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The United Arab Emirates also recently launched its Amal orbiter to the Red Planet. Amal, which is Arabic for Hope, will not land on Mars, but is the Arab world’s first interplanetary mission.

So far, the U.S. has been the only country to successfully put a spacecraft on Mars, doing it eight times. Two NASA landers are operating there, InSight and Curiosity. Six other spacecraft are exploring the planet from orbit: three U.S., two European and one from India.

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NASA’s longer-term goal is to send a manned mission to Mars in the 2030s. However, former astronaut Buzz Aldrin said he thought a slightly later target date of 2040 was more realistic. In an interview in 2016, the Gemini 12 and Apollo 11 astronaut told Fox News that by 2040, astronauts could visit Mars’ moon Phobos, which could serve as a sort of stepping stone to the Red Planet.

Fox News Chris Ciaccia, David Aaro and the Associated Press contributed to this report.

Follow James Rogers on Twitter @jamesjrogers