The first Israeli lunar spacecraft succeeded on Thursday in one of its biggest challenges en route to the moon: A maneuver allowing it to be captured by lunar gravity.
The maneuver required Beresheet to slow down from a velocity of 8,500 km/h to 7,500 km/h. Now, the spacecraft will go around the moon in diminishing orbits, until the last and greatest challenge: The landing itself expected next week.
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If it succeeds, Beresheet, or Genesis in English, will make space history and become the first privately-built spacecraft to complete the challenging mission. The very low cost of the project, in comparison to other moon missions, at $100 million, is also an important milestone in the new era of human interplanetary travel, which could be expected to grow and commercialize as a result of this mission’s success.
Eran Schmidt, deputy director of the project and head of ground systems for SpaceIL, said the spacecraft has thus far orbited the earth in a widening elliptical path, with the help of maneuvers aimed at adding to its speed and moving it further and further away from the earth.
At 5:18 P.M. Israel time, the spacecraft was at a distance of 400,000 kilometers away from the planet, and close to the moon. Then engines slowed it down, permitting it to get caught in the moon’s gravitational pull and then orbit the satellite elliptically, drawing as close as 500 kilometers from the moon’s surface.
The maneuver was completed autonomously via a series of instructions to the spacecraft’s computer.
At the next stage, the spacecraft would move to a distance of 200 kilometers from the moon and orbit it for 14 hours. Then an additional planned maneuver would bring the spacecraft to a height of 15 kilometers above the moon's surface, where it would receive a series of instructions leading to an autonomous landing, with the help of its engines. Once the vehicle comes within four to five meters off the moon’s surface the engines would shut off so that the aircraft could fall to the ground.
Experts hope the spacecraft’s special landing gear would permit it to survive the fall. The plan is for the landing to take place at sunrise as daytime temperatures on the moon are very high. The spacecraft will then be able to function for 72 hours before it becomes too hot.
If the maneuver had failed, the spacecraft could have had another opportunity within an hour or so later, Schmidt says, but if the second attempt had failed, it would have slipped out of both the earth’s and the moon’s gravitational pulls and winded up in another orbit around the sun. This would have spelled the mission’s failure.
Genesis, built by SpaceIL with the aid of Google’s XPRIZE and LunarX, began as competitors in 2007, who gave various entrepreneurs the challenge of building a space vehicle that could land on the moon, travel about 500 meters and send a video of what it could capture. The contest ended without any winners but all the competitors are continuing their efforts to build spacecraft that can reach the moon. In the next two years the entrepreneurs of the other projects hope to join Genesis in also landing aerial vehicles on the moon.
Last year the American space agency said nine U.S. companies or companies partnered with Americans could compete for LunarX tenders to fly NASA cargo to the moon. Last month NASA revealed the dozen tenders it wants to bring to the moon with a 2.6 billion dollar budget over 10 years.
Some of the private interest in moon exploration has to do with the development of technology to exploit the satellite’s mineral riches. It’s too soon to say whether the dream of exploiting moon resources can work out in the foreseeable future but many people regard the satellite as the new “wild west” and are looking for ways to take over some of it. Gold, silver, titanium and helium-3 isotopes needed for nuclear fusion can be found on the moon and in nearby asteroids. But the moon’s main economic value seems not only to be limited to its rare minerals but also in material that’s plentiful on the earth as well: water.
The price of fuel is one of the most expensive aspects of space travel. Huge quantities are needed to pull free of the earth’s orbit. Some 85% of the weight of the Saturn5 used to launch the American astronauts to the moon was made up of fuel. The same is true of rocket fuel to this day. By way of comparison, fuel makes up only 4% of the weight of the average car. Therefore if you want to plan long voyages in space the spacecraft have to carry enough fuel for the entire mission or find a way to refuel on the way. The moon could provide a place for such a refueling center. Frozen water at its poles could be broken down and used as rocket fuel. Therefore the one who succeeds in claiming the water on the moon’s poles will win a significant advantage in the race to conquer the solar system.
Aside from the history and the entrepreneurial achievements, success in capturing the moon would also launch Genesis’ scientific missions: To decode the magnetic mysteries of moon rocks. In research done in cooperation with Weizmann Institute use will be made of a magnetometer placed on the spacecraft to try to understand how moonrocks got their magnetism. Prof. Oded Aharonson of Weizmann’s earth sciences department, who heads the project, said that the moon doesn’t have any magnetic fields. But research has found that some moon rocks have magnetic qualities, and the research aims to try and find out how they acquired this capability: whether it happened as a result of an internal process that happened at an earlier phase of the moon’s life or due to an external factor such as an asteroid landing.
The earth’s magnetic field was created as a result of the circular movement of its metal and liquid core. But as far as scientists know the moon is much smaller and colder than the earth and its core is frozen. Therefore the moon is not believed to have its own magnetic field. The research aims to learn about the moon’s history via the magnetism of its rocks also to discover whether the moon may have had a magnetic field in the past. While the spacecraft orbits the moon in smaller and smaller circles, ahead of the landing, the magnetometer will measure the rocks’ magnetism in various regions, in order to learn whether there’s a system to the age and character of the magnetic rocks that could tell us something about their physical attributes.
https://www.haaretz.com/israel-news/.premium-israeli-spacecraft-maneuvering-to-leave-earth-s-orbit-and-capture-the-moon-1.7086309
2019-04-04 11:11:00Z
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