Israel is about to launch its first attempt to land on the Moon.
The Beresheet robot is a privately funded venture that aims to land and hop across the lunar surface.
It’s a challenging prospect. Only government space agencies from the US, Russia and China have previously managed soft touchdowns.
The 1.5m-high, 585kg Beresheet will begin its mission with a ride to Earth orbit on a SpaceX Falcon 9 rocket from Cape Canaveral in Florida.
Once ejected from this vehicle, the robot will then use its British-built engine to propel itself to the Moon. The journey will take over two months to complete.
SpaceIL, the non-profit behind the project, hopes Beresheet (“In the beginning” in Hebrew) will prove an inspiration to all those who follow its progress.
“By what we’re doing and achieving with the limited resources that we have, and the limited finances we had – I think we showed the Israeli ingenuity,” said key donor and SpaceIL chairman, Morris Kahn.
“We show our initiative, and we’ve developed technology, which I think is going to be important. I think we gotta take Israel into space,” he told reporters on Monday.
How was this project initiated?
Beresheet grew out of the Google Lunar XPRIZE, which offered financial incentives in 2007 to any non-government-funded team that could pull off a Moon landing.
None of the groups that entered the competition managed to meet its deadlines and the offer of prize money was withdrawn, but several of the participants did promise to keep working on their ideas, SpaceIL among them.
What will Beresheet do on the surface?
If the US$100m Beresheet craft can get down safely, it will take photos to send back to Earth and engage in some magnetic investigations. The targeted landing site is in a northern-hemisphere lava plain called Mare Serenitatis, where magnetic anomalies are known to exist.
The robot’s onboard magnetometer device will acquire measurements – and not just in one location, because Beresheet will, some hours after landing, hop to a new spot.
Prof Oded Aharonson, of the Weizmann Institute, leads Beresheet’s science team.
The Moon does not generate a global magnetic field, but on the surface, various areas or rocks are magnetic at different levels, he explains.
“If we can measure the magnetism of these rocks, we can begin to understand how and when this magnetism arose,” he added.
What’s the British connection?
It’s planned for Beresheet to keep operating for about two days on the lunar surface.
The success of the mission will depend in large part on the spacecraft’s UK-sourced Leros engine.
This type of power unit, developed by Nammo in Wescott, Buckinghamshire, is normally found firing on geostationary telecommunications satellites as they lift themselves to the right part of the sky over Earth after coming off the top of a launch rocket.
But Nammo’s engineers have adapted the Leros for Beresheet, shortening its nozzle and increasing its thrust.
The engine will do the job of pushing the robot out to the Moon from Earth, making sure the spacecraft is captured in lunar orbit, and then taking the probe gently down to the surface. The Leros unit will also execute the 500m hop across Mare Serenitatis.
One of the attractions of the Leros is that it can handle multiple, so-called “hot re-starts”, says Nammo propulsion team leader Rob Westcott.
“Normally, when people use our engines they will start them up and leave them running for hours at a time before shutting them down for perhaps days, even weeks,” he explained.
“This gives an engine plenty of time to cool down. In this case, however, SpaceIL wanted to fire up the engine, stop it, and then fire it again after just a few seconds while it is still very hot. They need this for the landing and hopping phases.”
What about the future?
Whatever happens, Beresheet will go down as a pathfinder. Other privately funded lunar spacecraft are set to follow it.
Both the US and European space agencies have stated their intention to use commercial landers to deliver some of their scientific payloads to the Moon.
The lift-off of the Beresheet’s Falcon 9 from Cape Canaveral is timed for 20:45 EST, Thursday (01:45 GMT, Friday).
The robot is actually piggybacking a ride on the flight, which has the primary function of placing a new telecoms satellite in orbit for the Indonesian company Pasifik Satelit Nusantara.
and follow me on Twitter: @BBCAmos