Demonstração de relé de comunicação a laser da NASA: levando dados espaciais ao solo com lasers

Por Matthew D. Peters, Goddard Space Flight Center da NASA, 5 de dezembro de 2021

O LCRD transmitirá dados entre a Estação Espacial Internacional e o solo. Crédito: Laboratório de imagens conceituais do Goddard Space Flight Center da NASA

NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion." NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]">NASA launches satellites, rovers, and orbiters to investigate humanity's place in the Milky WayThe Milky Way is the galaxy that contains our Solar System and is part of the Local Group of galaxies. It is a barred spiral galaxy that contains an estimated 100-400 billion stars and has a diameter between 150,000 and 200,000 light-years. The name "Milky Way" comes from the appearance of the galaxy from Earth as a faint band of light that stretches across the night sky, resembling spilled milk." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"> Via Láctea. Quando essas missões chegam aos seus destinos, seus instrumentos científicos capturam imagens, vídeos e informações valiosas sobre o cosmos. A infraestrutura de comunicações no espaço e no solo permite que os dados coletados por essas missões cheguem à Terra. Sem estações terrestres para recebê-los, os dados extraordinários captados por essas missões ficariam presos no espaço, impossibilitados de chegar a cientistas e pesquisadores na Terra.

Desde o início da exploração espacial, as missões da NASA dependem principalmente de comunicações de radiofrequência para essa transferência de informações. Mas neste outono, o Laser Communications Relay Demonstration (LCRD) da NASA lançará e mostrará as comunicações a laser - uma maneira revolucionária de comunicar dados do espaço para o solo.

As estações terrestres do LCRD, conhecidas como Optical Ground Station (OGS) -1 e -2, estão localizadas em Table Mountain, Califórnia, e Haleakalā, Havaí. Esses locais remotos e de alta altitude foram escolhidos por suas condições climáticas claras. Embora as comunicações a laser possam fornecer maiores taxas de transferência de dados, distúrbios atmosféricos - como nuvens e turbulência - podem interromper os sinais de laser à medida que entram na atmosfera da Terra.

As estações terrestres do LCRD, Optical Ground Station -1 e -2, permitirão o sucesso da missão. Crédito: Goddard Space Flight Center da NASA

"Do jeito que a meteorologia local funciona, há poeira mínima e menos turbulência atmosférica no topo da montanha, o que é ótimo para comunicações a laser", disse Ron Miller, do Goddard Space Flight Center da NASA em Greenbelt, Maryland, e ex-líder de desenvolvimento da OGS-2 no Havaí. "Está a cerca de 10.000 pés de altura, então você está acima de grande parte da atmosfera e do clima que ocorre abaixo do cume. É muito comum ter um belo dia de sol no topo e estar nublado no meio da montanha."

Os engenheiros de comunicações da NASA selecionaram esses locais porque seus padrões climáticos geralmente se complementam. Quando o OGS-1 na Califórnia está nublado, o OGS-2 no Havaí tende a ser claro – e vice-versa. Para monitorar a cobertura de nuvens e determinar qual estação deve ser usada, o parceiro comercial Northrop Grumman forneceu uma estação de monitoramento atmosférico que observa as condições meteorológicas em Haleakalā. Esta estação de monitoramento funciona de forma quase autônoma, 24 horas por dia, sete dias por semana. O OGS-1 possui recursos de monitoramento climático semelhantes em Table Mountain.

While OGS-2 was developed specifically for the LCRD mission, OGS-1 is based at JPLThe Jet Propulsion Laboratory (JPL) is a federally funded research and development center that was established in 1936. It is owned by NASA and managed by the California Institute of Technology (Caltech). The laboratory's primary function is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA's Deep Space Network. JPL implements programs in planetary exploration, Earth science, space-based astronomy and technology development, while applying its capabilities to technical and scientific problems of national significance." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"JPL's Optical Communications Telescope Laboratory, which prior to LCRD was used for previous laser communications demonstrations. To get OGS-1 ready for LCRD support, engineers had to upgrade the ground station, modifying the system to bring it up to a higher standard. One such upgrade involved replacing the mirrors to have better reflectivity and higher laser thresholds so that the telescope can receive and send laser signals to and from LCRD./p>

After the experimental phase, LCRD will support in-space missions. Missions, like a terminal on the International Space StationThe International Space Station (ISS) is a large spacecraft in orbit around the Earth that serves as a research laboratory and spaceport for international collaboration in space exploration. It was launched in 1998 and has been continuously occupied by rotating crews of astronauts and cosmonauts from around the world since 2000. The ISS is a joint project of five space agencies: NASA (USA), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada). It orbits the Earth at an altitude of approximately 400 kilometers (250 miles), and provides a unique platform for scientific research, technological development, and human space exploration." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"International Space Station, will send data to LCRD, which will then beam it to OGS-1 or OGS-2./p>

LCRD is led by Goddard and in partnership with JPL and the MITMIT is an acronym for the Massachusetts Institute of Technology. It is a prestigious private research university in Cambridge, Massachusetts that was founded in 1861. It is organized into five Schools: architecture and planning; engineering; humanities, arts, and social sciences; management; and science. MIT's impact includes many scientific breakthroughs and technological advances. Their stated goal is to make a better world through education, research, and innovation." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"MIT Lincoln Laboratory. LCRD is funded through NASA's Technology Demonstration Missions program, part of the Space Technology Mission Directorate, and the Space Communications and Navigation (SCaN) program at NASA Headquarters in Washington, D.C. Goddard manages OGS-2, while JPL manages OGS-1./p>