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Как устроена связь между Землёй и Луной
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What is LLCD?
Compared to the days of dial-up, today's web-sites load at lightning speed. Just like you need your web-pages load quickly and securely, NASA scientists and engineers want the same quick connectivity with their data-gathering spacecraft. To meet these demands NASA is moving away from their form of dial-up (radio frequency-based communication), to their own version of high-speed Internet; using laser communications.
Launched in September 2013 from NASA's Wallops Flight Facility in Virginia, LADEE began orbiting the moon Oct. 6 and gathering science data Nov. 10. The spacecraft entered its science orbit around the moon's equator on Nov. 20, and in March 2014, LADEE extended its mission operations following a highly successful 100-day primary science phase.
LADEE also hosted NASA’s first dedicated system for two-way communication using laser instead of radio waves. The Lunar Laser Communication Demonstration (LLCD) made history using a pulsed laser beam to transmit data over the 239,000 miles from the moon to the Earth at a record-breaking download rate of 622 megabits-per-second (Mbps). In addition, an error-free data upload rate of 20 Mbps was transmitted from the primary ground station in New Mexico to the Laser Communications Space Terminal aboard LADEE.
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Data, transmitted in the form of hundreds of millions of short pulses of light every second, will be sent by the Lunar Lasercomm Space Terminal (LLST), aboard the LADEE spacecraft.
The LLST, developed by MIT Lincoln Laboratory, is comprised of three modules: an Optical Module (OM), a Modem Module (MM), and a Controller Electronics (CE) module. The optical module is situated on the exterior of the LADEE spacecraft payload module, while the Modem and Controller Electronics are mounted on the interior of the spacecraft. The LLST payload weighs about 65 pounds (30 kg.) (Что даёт стоимость доставки на орбиту в $ 100 тыс. - QQ)
LLCD's Optical ModuleThe OM consists of a four-inch diameter (10-cm) telescope used to transmit and receive a modulated laser beam to and from the Earth ground station, respectively. Vibrations on the LADEE spacecraft are measured and compensated by the OM, providing the stabilization necessary for accurate beam pointing to the ground terminal. The OM is mounted on a 2-axis gimbal for coarse pointing, contains an acquisition detector, and is fiber-coupled to the Modem Module.
Modem Module
LLCD's Modem ModuleThe MM resides within the LADEE spacecraft and contains the optical transmitter and receiver. The MM is mounted inside LADEE and contains the 0.5-watt infrared laser transmitter that will transmit data at a rate of 622 Mbps from the Moon to Earth. The MM also contains the highly sensitive receiver that deciphers the light pulses of data sent from the ground telescopes at up to 20 Mbps. It comprises four slices: a power slice that provides power conditioning for some of the major functions, a digital slice containing high-speed digital components, an analog slice that includes the analog signal processing used in receiving and demodulating the uplink signals, and an electro-optic slice that includes a 0.5-watt power amplifier for the modulated downlink signal plus an amplifier and detector for receiving the uplink data signal, as well as the electro-optics to create the downlink signal and also demodulate the optical uplink tracking signal. Lastly, the MM provides a high-speed data interface with the LADEE spacecraft for downlinking the spacecraft telemetry as well as instrument science data.
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Про связь с Вояджерами было тут.
* * *
What is LLCD?
Compared to the days of dial-up, today's web-sites load at lightning speed. Just like you need your web-pages load quickly and securely, NASA scientists and engineers want the same quick connectivity with their data-gathering spacecraft. To meet these demands NASA is moving away from their form of dial-up (radio frequency-based communication), to their own version of high-speed Internet; using laser communications.
Launched in September 2013 from NASA's Wallops Flight Facility in Virginia, LADEE began orbiting the moon Oct. 6 and gathering science data Nov. 10. The spacecraft entered its science orbit around the moon's equator on Nov. 20, and in March 2014, LADEE extended its mission operations following a highly successful 100-day primary science phase.
LADEE also hosted NASA’s first dedicated system for two-way communication using laser instead of radio waves. The Lunar Laser Communication Demonstration (LLCD) made history using a pulsed laser beam to transmit data over the 239,000 miles from the moon to the Earth at a record-breaking download rate of 622 megabits-per-second (Mbps). In addition, an error-free data upload rate of 20 Mbps was transmitted from the primary ground station in New Mexico to the Laser Communications Space Terminal aboard LADEE.
* * *
Data, transmitted in the form of hundreds of millions of short pulses of light every second, will be sent by the Lunar Lasercomm Space Terminal (LLST), aboard the LADEE spacecraft.
The LLST, developed by MIT Lincoln Laboratory, is comprised of three modules: an Optical Module (OM), a Modem Module (MM), and a Controller Electronics (CE) module. The optical module is situated on the exterior of the LADEE spacecraft payload module, while the Modem and Controller Electronics are mounted on the interior of the spacecraft. The LLST payload weighs about 65 pounds (30 kg.) (Что даёт стоимость доставки на орбиту в $ 100 тыс. - QQ)
LLCD's Optical ModuleThe OM consists of a four-inch diameter (10-cm) telescope used to transmit and receive a modulated laser beam to and from the Earth ground station, respectively. Vibrations on the LADEE spacecraft are measured and compensated by the OM, providing the stabilization necessary for accurate beam pointing to the ground terminal. The OM is mounted on a 2-axis gimbal for coarse pointing, contains an acquisition detector, and is fiber-coupled to the Modem Module.
Modem Module
LLCD's Modem ModuleThe MM resides within the LADEE spacecraft and contains the optical transmitter and receiver. The MM is mounted inside LADEE and contains the 0.5-watt infrared laser transmitter that will transmit data at a rate of 622 Mbps from the Moon to Earth. The MM also contains the highly sensitive receiver that deciphers the light pulses of data sent from the ground telescopes at up to 20 Mbps. It comprises four slices: a power slice that provides power conditioning for some of the major functions, a digital slice containing high-speed digital components, an analog slice that includes the analog signal processing used in receiving and demodulating the uplink signals, and an electro-optic slice that includes a 0.5-watt power amplifier for the modulated downlink signal plus an amplifier and detector for receiving the uplink data signal, as well as the electro-optics to create the downlink signal and also demodulate the optical uplink tracking signal. Lastly, the MM provides a high-speed data interface with the LADEE spacecraft for downlinking the spacecraft telemetry as well as instrument science data.
* * *
Про связь с Вояджерами было тут.