Sent to the moon, an Israeli private spacecraft “Genesis” 11 APR have to land in the crater of the Sea of Clarity, that in the Northern hemisphere of the visible side of our natural satellite. On Board the spacecraft is a small device, the successful verification of which will in the future substantially more accurate (with an accuracy to a few centimeters) to make payments to places of landings for robotic and manned missions on the surface of the companion of the Earth.
Spacecraft “Bereshit”, whose name in Hebrew translates as “in the beginning, was sent to the Earth on February 21. Research lander is the brainchild of private Israeli nonprofit organization SpaceIL and Israel Aerospace Industries. As part of the flight, the unit made several scheduled corrective maneuvers around the Earth, making almost went into orbit around the satellite.
Together with the lander, “in the beginning” to the moon set off a small device called retroreflection. It gave the American space Agency NASA. The device is a system of quartz mirrors are enclosed within the domed aluminium frame.
If “Genesis” will successfully land on the moon on 11 April, the orbiting satellite spacecraft NASA’s Lunar Reconnaissance Orbiter (LRO) uses its(instrument for measuring height) and “fire” retroreflector lander laser pulses. Because of this, says the project team, they will be able with accuracy to 10 centimeters to determine the location of the unit on the lunar surface.
In the future, NASA plans to send to the moon many of the same retroreflector. They will all serve as fiducial markers. That is, the spacecraft that will be sent to the moon, will be able to use these devices for making very accurate landings in scheduled areas.
Retroreflector (LRA), which NASA has provided for “Bereshit”, was developed by engineers and scientists of Center for space launches of a name of Goddard and mit. It is located on top of the lander, so easily visible from orbit.
Retroreflector not perform any active function. It will be used in tandem with the lunar orbital laser(LOLA) LRO spacecraft. Rays that hitand reflected from the lunar surface. After each pulse LOLA holds the timing of the movement of the beam up to the surface and based on this calculates the distance to it.
While “Genesis” will perform initially the tasks assigned to it, to use installed on it retroreflector will not. The reason is that the lasercan damage more sensitive equipment that is on Board the lander. To avoid it, and experiment with retroreflection apparatus will be after the “Genesis” of his “dying away,” says project Manager LOLA from the Massachusetts Institute of technology David Smith.
“This experiment is aimed at testing the concept. It will continue as long as possible. Perhaps, until that time, until the LOLA instrument on Board LRO will remain operational. By the way, in June of this year will be the anniversary – time of the device on the orbit of the satellite would be 10 years,” says Smith.
Smith notes that the system of lasers was invented and developed by him and his colleague from space flight Center Goddard about 15 years ago, to the mission space lander “Phoenix”, who worked on Mars.
“It was assumed that this retroreflector will be paired with a lasermounted on the orbiting spacecraft Mars Global Surveyor. Unfortunately, by the time when the lander landed on the Red planet, an instrument on the space station is out of order,” explains Smith.
According to the engineer, the main purpose of deployment of laser systems on Mars and the moon is to use these devices to determine the exact location of the planting apparatus with orbital stations. However, the method has one drawback – it precision was to limit the size of the area of the surface, which is illuminated by a laser pulse. According to Smith, the laser, giving a diameter of 5-meter “point” on the surface of a celestial body requires a very accurate guidance system. In this case, of course, it would be easier to use a wider laser beams to determine the location of the reflector, however, it very much will reduce the accuracy of the data on the location of the device on the surface.
The device LRO orbiting the moon
The lone laser on the moon
“Properly adapted to the range measurement can solve this problem. Still, the LOLA instrument was designed to measure the height, not the distance from a small system of reflectors. But for the near future – this is the only available laser on the satellite of our planet,” says Smith.
Using images of the surface, which makes the Orbiter, LRO, scientists will be able to ascertain the location of the Israeli module of Beresheet. Therefore, the emphasis in this experiment is aimed to understand how difficult it will be for the LRO to determine the distance to the lander.
“If you position around the landing zone a few small reflectors, in the framework of future missions can land directly at this point. This system does not require power so it can run on the moon’s surface decades, perhaps even longer,” adds Smith.
The lunar orbital laser(Lunar Orbiter LaserLOLA) aboard the spacecraft NASA’s Lunar Reconnaissance Orbiter. With the help of it and retroreflector installed on Israeli lander “Genesis” scientists can calculate the exact landing place of the last
Use in the future
According to Smith, such a compact retroreflector planned to be installed on other celestial bodies, including small, for example, the same asteroids. Setting (or resetting) a certain number of such reflectors on the surface of the object would allow working around that object probes to carry out more accurate calculations of their characteristics, for example, more accurate control of their speed, location, relative to the Earth, and their form.
“Since the reflectors can work for decades, the interested object can be explored by several spacecraft in different missions. In addition, the presence of these reflectors on the surface will simplify the planting apparatus to the interested celestial body,” adds Smith.
Of course, a very compact reflectors have a limited range. According to Smith, existing in the Center of space launches name Goddard prototypes able to capture laser pulses from a distance of about 10,000 kilometers.
“The weight of the compact reflector is only about 20 grams, but larger will allow you to define them with much greater distances. At the same time, “big” means more severe. And the advantage of small is that you can install them on virtually any a small lander,” says Smith.