The importance of using light and laser in space industry

The use of laser light in the space industry is one of the most important and advanced technologies used in various fields. Below are some of the applications of laser light in the space industry:
Space communications: Lasers are used as high-speed light sources in space communications. Through laser waves, data can be transmitted at high speed and with high quality between spacecraft, satellites and space systems.
Accurate measurement and measurement: Lasers are used in the space industry for accurate measurement and measurement. By using laser technology, it is possible to measure the distance to spatial objects and structures with high accuracy and at large distances.
Spatial mapping: lasers are used in the process of mapping and making detailed maps of the surface of the moon and planets. By using laser systems, it is possible to register and map precise three-dimensional structures of the space environment.
Power transmission: Lasers are used as an advanced method for wireless power transmission in space. This technology allows spacecraft and space systems to receive power wirelessly from ground power sources or from other spacecraft and satellites.

History of the use of lasers for detection

Sending light to the moon, as one of the scientific and technological achievements in the field of space exploration, began in the 1960s. In this decade, the American space program named “Apollo” began to send humans to the moon. During this program, between 1969 and 1972, 6 Apollo space missions were carried out, which eventually led to the landing of astronauts on the surface of the Moon.
In these missions, light was sent to the moon by means of photographic flashes and photometry equipment. These lights were used to create sufficient lighting in dark areas and to review and record images and videos. Also, light was used as a measuring tool in some scientific experiments.
In addition to the American program, other space programs were started by other countries in the following decades. For example, in 1970, the Russians started the Luna program, which aimed to send research vehicles to the moon.
Since then, space programs and exploration of the moon have continued by various countries and space organizations. Today, as technology advances and communication and imaging methods evolve, sending light to the moon is used for scientific study, commercial uses, and even space tourism experiences.
Dozens of times in the past decade, NASA scientists have fired laser beams at a reflector 385,000 kilometers from Earth. Together with their French colleagues, they announced today that they have detected a signal for the first time, an encouraging result that could boost laser experiments used to study the physics of the universe.
Since Apollo, scientists have used lunar reflectors to learn more about our nearest neighbor. This is a simple experiment: aim a beam of light at the reflector and calculate how long it takes for the light to return. Decades of doing this measurement have led to great discoveries.
Apollo 11 and 14 were delivered in 1969 and 1971 respectively. Each is made of 100 mirrors, which scientists call corner cubes, because they are like the corners of a glass cube.
The advantage of these mirrors is that they can reflect light in any direction it comes from. Another panel with 300 cube corners was dropped by the Apollo 15 astronauts in 1971. The Soviet robotic Mars rovers, Lunokhod 1 and 2, which landed in 1970 and 1973, have two additional reflectors, each with 17 mirrors. Collectively, these reflectors constitute the last working science experiment of the Apollo era.

NASA

Laser communication relay display test

Or in short, the Laser Communications Relay Demonstration test of NASA’s technology
has been mounted on the American Space Force satellite, and it went into space at 5:19 on December 7 (13:49 Tehran time) from the Cape Canaveral space base. The launch was previously scheduled for a few days ago, but a leak in the kerosene fuel storage system on the launch pad delayed it by two days.
The mission is in orbit to conduct a two-year series of experiments to investigate how optical communication links can help download large amounts of information faster than traditional communication systems. The goal of the project is to demonstrate the capabilities of NASA’s first full two-way test of a communications system that can transmit data at rates between 10 and 100 times faster than current radio frequency base systems
, said Trudy Kortes, director of technology demonstrations
for the Technology Missions Office. Optical uploading to transmit data to us using lasers is really a great technology demonstration.

Structure of LCRD

It consists of two optical communication terminals and a switching unit that allows the device to receive the signal, transfer the data to the transmitter and then send the signal to the destination.
It works with infrared lasers that are invisible to the human eye. LCRD
wavelengths of lasers are 10,000 times shorter than radio waves and thus can travel in narrower beams. However, they are still limited by the laws of physics and move at the speed of light.
It transmits data between the mission’s ground stations. LCRD Initial Tests
Next year, NASA plans to send a laser communications terminal to the International Space Station on a commercial cargo spacecraft.
The mobile object allows to test an optical link with an LCRD to the ISS system in this payload
orbits the Earth at a speed of 8 km/s. The laser terminals in the current technology test download data at a rate of 1.2 gigabits per second, and the system can receive data at a similar rate from the space station.
To check more precisely what the structure of this spacecraft is, pay attention to the following article:
1. The communication payload of this section includes the laser communication terminal, which is responsible for establishing laser communication between the satellite and the ground stations.
2. The host satellite hosts the communications payload. The host satellite may be a commercial satellite provided by a space company for this purpose.
3. Chips and electronic equipment: used for the operation of the laser communication terminal and chips and electronic equipment needed for data processing and transmission. It includes laser communication chips, sensing and control equipment, electronic circuits and other related components.
4. Ground stations, a ready ground includes data receiving and sending stations and required control and processing systems. Ground stations establish laser communications and receive and send data using laser equipment connected to the laser communications terminal on the satellite.

LCRD mission objective

NASA’s LCRD plans to test a variety of uses during its initial two-year mission,
allowing NASA to learn how optical communications will perform in a larger network. Test data will include spacecraft health telemetry, tracking and command data, and sample user data, according to NASA.
Direct optical communication to Earth was previously tested in 2013 and 2014 by spacecraft orbiting the Moon. But the test time was limited because the laser payload was considered a secondary objective in the mission. NASA now has enough time to demonstrate the technology in action and can refine the current models by conducting a variety of experiments and collecting large amounts of data.
According to NASA, the test of laser communication opens the way for other organizations and companies.
Developed prior to the deployment of the Starlink network,
it is not compatible with LCRD terminals but the laser payload of SpaceX’s Internet fleet. The experiment is led by NASA’s Goddard Space Flight Center with support from the Piranha Jet Experiment and MIT’s Lincoln Laboratory.

The proof of application of relay services is two-way optical communication between the geosynchronous circuit and the ground. The project supports advanced communications, navigation, and avionics key focus areas of exploration. This effort will prove optical communication technology in an operational environment, providing data rates up to 100 times faster than today’s radio frequency-based communication systems. The demonstration will measure and characterize system performance under various conditions, develop operating procedures, evaluate feasibility for future missions, and provide in-circuit capability to test and demonstrate standards for optical relay communications. This capability, if successfully demonstrated, could be quickly injected into NASA missions, other federal agencies, and US satellite manufacturers and operators as demand for bandwidth increases.

Laser specifications

The diameter of this laser is about three quarters of an inch and it sends optical signals to the moon at a speed of 1.2 gigabits per second. This amount can illuminate an area of ​​one kilometer on the moon. The weight of this laser is about one ton. These lasers are 44 times smaller than radio receivers.

Launch LCRD

It was originally supposed to launch in 2016 on a commercial communications spacecraft, but NASA switched the payload to a Space Force satellite. Delays in the construction of the spacecraft delayed the launch until mid-2021, and after a change in the Atlas 5 launch schedule, the mission was postponed to the end of the year. It was finally launched on December 7.