This is a feat that has only been accomplished by three nations — the United States, the former Soviet Union and China. The SpaceIL lander is named Beresheet, which means “Genesis” or “in the beginning” in Hebrew.
The mission costs about $100 million, far less than government-sponsored spacecraft that have been to the moon, although it is designed to survive just a few days, and it is not carrying sophisticated payloads.
If the landing succeeds, it would validate the faster and cheaper approach that space agencies and private companies seeking lunar business opportunities want to pursue. A failure would point out that these small missions are also inherently riskier and that backers must be willing to accept periodic failures.
When will Beresheet land, and how can I follow it?
Shortly after 3 p.m. Eastern time, the spacecraft began its maneuvers to head toward the moon’s surface. Landing is scheduled for 3:25 p.m. Eastern time. That’ll be 10:25 p.m. in Israel.
“We have passed the point of no return; we are in the landing process,” said Opher Doron, general manager of Israel Aerospace Industries’ space division, which collaborated with SpaceIL on building Beresheet.
SpaceIL will stream its coverage of the event on YouTube.
The stream is coming from the mission’s command center, which is in the industrial zone of Yehud, a small city near Ben Gurion Airport. The stream showed Prime Minister Benjamin Netanyahu, who appeared to win re-election earlier this week, and his wife, Sara, visiting the mission’s managers in the minutes before the landing attempt.
Outside, approximately 2,500 people were gathered on a lawn nearby the facility to follow the mission’s progress.
Where will it land?
The landing site is within a lava plain known as the Sea of Serenity. The spacecraft is aiming at an 86-mile-wide target area in the northeastern section of the plain, chosen largely because it is flat with few craters.
How will Beresheet land on the moon?
The spacecraft is in an elliptical orbit that brings it as close as 10 miles from the surface, looping around once every two hours.
As it approaches the moon, at a distance about 525 miles, an automated sequence will fire the main engine to slow the spacecraft down. If for some reason the engine does not fire, the spacecraft can abort and go around the moon for a later attempt.
But once the engine powers up, there is no turning back.
When it is less than 1 mile above the moon, the spacecraft will rotate to descend vertically. Then, when it just 16 feet above the surface, the engine will shut off, allowing the lander to fall slowly to the ground.
This is the riskiest part of the mission.
Beresheet is using a laser to measure its altitude. “It's a system that was quite challenging in the development and arrived quite late,” Doron said. That limited the amount of testing.
Even if everything works as designed, the landing could still fail if by chance Beresheet sets down on a boulder or on a steep slope. The spacecraft has no means to identify obstacles and avoid them.
“Basically, we're landing blind,” Doron said. “It’s a very challenging landing to get right. We’re hoping it will go well.”
What will it do once it gets to the lunar surface?
An instrument built by the Weizmann Institute of Science is to measure the moon’s magnetic field as the spacecraft approaches for landing. That information could reveal something about the iron core far below the surface.
NASA provided the spacecraft with retroreflectors, essentially, mirrors that reflect light in the same direction as the incoming beam. Lasers on Earth shined at that spot will bounce back, enabling precise measurement of the distance between Earth and the moon. Apollo astronauts left similar devices on the moon nearly 50 years ago.
The spacecraft is also a time capsule containing hundreds of digital files, including the Torah, the Israeli flag, artwork contributed by the public and a children’s book that was inspired by SpaceIL’s mission to the moon.
It also will ferry a digital archive containing 30 million pages of information — including a full version of the English-language Wikipedia encyclopedia — provided by the Arch Mission Foundation, a nonprofit seeking to create a backup of humanity’s knowledge.
But the mission won’t last long. Beresheet is not designed to operate for more than a few days. It will land at the beginning of a lunar day. The electronics are not designed to survive the hotter temperatures that prevail on the moon’s surface as the sun gets higher in the moon’s sky.
Why did it take so long for the probe to get to the moon?
The spacecraft, launched in February, took a long but fuel-efficient route. Instead of blasting out of Earth’s orbit, it gradually elongated its elliptical orbit until it passed close enough to the moon to be captured by lunar gravity. Then it spent a few more days making its orbit around the moon more circular before attempting a landing.
What other moon landing plans are happening this year and in the years ahead?
India is planning to send a robotic lander later this year. NASA is also planning to hire commercial companies to send experiments to the moon. In January, a Chinese spacecraft became the first to make an intact landing on the far side of the moon.
This article originally appeared in The New York Times.