Optical Payload for Lasercomm Science

Last updated
OPALS
OPALS laser beams data to Earth.jpg
Artist's rendering of an OPALS downlink Image credit JPL/Caltech
Operator Jet Propulsion Laboratory
ManufacturerJet Propulsion Laboratory
Instrument typeCommunications
Function Laser Communications
Mission duration90 days
Began operations18 April 2014
Website http://phaeton.jpl.nasa.gov
Properties
Mass159 kilograms [1]
Number launched1
Data rate50 Mb/s
Host spacecraft
SpacecraftInternational Space Station
Launch date18 April 2014
RocketFalcon 9 Dragon Capsule
Launch siteCape Canaveral
COSPAR ID 1998-067A
Orbit Low Earth Orbit

Optical Payload for Lasercomm Science (OPALS) is a spacecraft communication instrument developed at the Jet Propulsion Laboratory that was tested on the International Space Station (ISS) from 18 April 2014 to 17 July 2014 to demonstrate the technology for laser communications systems between spacecraft and ground stations. [2]

Contents

The purpose of OPALS is to do research into replacing traditional radio-frequency (RF) communications which are currently used on spacecraft. [3] This will allow spacecraft to increase the rate at which data is downlinked by 10 to 100 times. [4] It also will have less error than RF communication. [3]

It launched from Cape Canaveral to the ISS on 18 April 2014 on a Falcon 9 SpaceX CRS-3 Dragon capsule resupply. [5]

The experiment used commercial products rather than space qualified components. [6]

Science objectives

The goal of the OPALS mission was to demonstrate a downlink of a short video from space using laser communication. In doing so, the following was studied:

Mission architecture

Communications and commands were sent to the flight system via the Mission Operations System (MOS), which is a process developed by the OPALS team. When the team wanted to execute a laser downlink, it went as follows [7]

  1. The information starts at the flight MOS located the mission control at JPL, where communications with the flight system is planned
  2. Information is sent to the Huntsville Operations Support Center (HOSC) at the Marshall Space Flight Center where it is sent via RF to the Tracking Data and Relay Services System (TDRSS), which is a communications satellite array
  3. The TDRSS sends the information to the ISS and the flight system, again via RF
  4. The flight system executes the laser downlink, which is received by the Optical Communications Telescope Laboratory (OCTL) in Wrightwood, California, where the OPALS ground system is located
  5. The information is finally given to the principal investigator of the OPALS mission for the team to analyze

This process is executed in a matter of seconds. [8] In the case of communications that are not laser transmission (e.g. system health checks), the architecture is much the same. The uplink is the same, following steps 1-3. The downlink instead of going down to the OCTL goes through the same path as the uplink, except backwards. [7] Just like the uplink, all the communications are via RF.

Although most downlinks went through the OCTL, some went through other ground stations, including the German Aerospace Center's (DLR) optical ground station in Oberpfaffenhofen, Germany and the European Space Agency's ground station in Mount Teide, Tenerife, Canary Islands. [9] [6]

Systems

OPALS flight system Image credit JPL/Caltech OPALS - Flight System (1).png
OPALS flight system Image credit JPL/Caltech

The OPALS has two hardware systems: the flight system, which sends the laser downlinks from the ISS, and the ground system, which helps the flight system know where to point and receives its downlinks.

Flight system

The flight system (depicted on the right) has three major parts, the sealed container, the optical gimbal transceiver, and the Flight Releasable Attachment Mechanism (FRAM). [10]

The sealed container houses the electronics, avionics, the communications laser, and a custom power board pressurized to 1 atmosphere with air to keep the electronics cool. [7] [10] The laser uses a light wavelength of 1,550 nanometers with 2.5 watts of power [11] [12] and has a 2.2 centimeter diameter aperture. [9] [6] The laser was routed through fiber to the gimbal transceiver where it was transmitted with 1.5 milliradian beam divergence. [12]

OPALS under construction Image credit JPL/Caltech Opals20130712-640-640x350.jpg
OPALS under construction Image credit JPL/Caltech

The optical gimbal transceiver holds the uplink camera and the laser collimator on a 2-axis gimbal. [10] Due to laser safety considerations, the gimbal may not shine on anything on the ISS. [7] To avoid this, the gimbal is designed with mechanical stops and electromechanical limit switches so that its field of regard (the area where it can point) is limited to 36° wide in elevation and 106° in azimuth, where the azimuthal axis is generally in the direction of motion of the ISS. [7] Because of the gimbal field of regard geometry, the flight system can only perform downlinks when the ISS is north of the ground station.

Because of the fast-changing viewing geometry during passes, the direction in which the gimbal must point throughout the pass must be pre-computed. [13] The list of directions for the gimbal to point was calculated based on the ISS GPS state vector and attitude quaternion. [13] The need for this list to be accurate was very important because of error in ISS orientation predictions and because the gimbal lacked any encoders, so all gimbal movement had to be done through dead reckoning. [13] Once the flight system detects the beacon from the ground system, it tracks beacon with the gimbal. [13]

The FRAM is the interface between OPALS and the ISS. [10] It was not designed by the OPALS team, but was an existing part designed by the ISS team at Johnson Space Center. [14]

Ground system

The ground system is what receives the signal from the flight system's laser downlinks. [7] Most frequently, the Optical Communications Telescope Laboratory (OCTL) in Wrightwood, California was used as the ground station, but other international stations were used as well. The observatory has a 1-meter mirror through which all of the laser downlinks are performed. [13] The telescope has the capability of tracking objects that are in Low Earth Orbit. [13] The ground system's function is to indicate to the flight system where to point the laser and then to receive that signal. It indicates where the laser must point by illuminating the ISS with a 976 nanometer laser. [7] Signal is received through a 3 nanometer bandpass 1550 nanometer spectral filter in front of an indium gallium arsenide acquisition camera and an avalanche photodiode detector, which keeps the receiver from being overwhelmed by sunlight backscattered by Earth's atmosphere during day passes. [13]

Results

OPALS attempted 26 downlinks, of which 18 were successful. Half of the successes were attempted at night, and half during the day. [13] Despite many downlinks being considered a failure, some of those failures were able to send the entire data package, since downlink data consisted of the same data package repeated many times.

Generally, downlinks were more successful in the day than in the night. Downlinks also suffered in the event of cloudy weather, although on some occasions it was able to reacquire the signal. Some difficulty was found with downlinks to high-latitude ground stations, like DLR.

See also

Related Research Articles

<span class="mw-page-title-main">Free-space optical communication</span> Communication using light sent through free space

Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking. "Free space" means air, outer space, vacuum, or something similar. This contrasts with using solids such as optical fiber cable.

<span class="mw-page-title-main">NASA Deep Space Network</span> Network of radio communication facilities run by NASA

The NASA Deep Space Network (DSN) is a worldwide network of spacecraft communication ground segment facilities, located in the United States (California), Spain (Madrid), and Australia (Canberra), that supports NASA's interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the Solar System and the universe, and supports selected Earth-orbiting missions. DSN is part of the NASA Jet Propulsion Laboratory (JPL).

<span class="mw-page-title-main">Goldstone Deep Space Communications Complex</span> US observatory near Barstow, California

The Goldstone Deep Space Communications Complex (GDSCC), commonly called the Goldstone Observatory, is a satellite ground station located in Fort Irwin in the U.S. state of California. Operated by NASA's Jet Propulsion Laboratory (JPL), its main purpose is to track and communicate with interplanetary space missions. It is named after Goldstone, California, a nearby gold-mining ghost town.

<span class="mw-page-title-main">Milstar</span> Constellation of American military satellites

Milstar is a constellation of military communications satellites in geosynchronous orbit, which are operated by the United States Space Force, and provide secure and jam-resistant worldwide communications to meet the requirements of the Armed Forces of the United States. Six spacecraft were launched between 1994 and 2003, of which only five were operational after launch; the third launch failed, both damaging the satellite and leaving it in an unusable orbit.

<span class="mw-page-title-main">Interplanetary Internet</span> Model of Internet between planets

The interplanetary Internet is a conceived computer network in space, consisting of a set of network nodes that can communicate with each other. These nodes are the planet's orbiters and landers, and the Earth ground stations. For example, the orbiters collect the scientific data from the Curiosity rover on Mars through near-Mars communication links, transmit the data to Earth through direct links from the Mars orbiters to the Earth ground stations, and finally the data routed through Earth's internal internet.

<span class="mw-page-title-main">Mars Telecommunications Orbiter</span> Cancelled Mars mission

The Mars Telecommunications Orbiter (MTO) was a cancelled Mars mission that was originally intended to launch in 2009 and would have established an Interplanetary Internet between Earth and Mars. The spacecraft would have arrived in a high orbit above Mars in 2010 and relayed data packets to Earth from a variety of Mars landers, rovers and orbiters for as long as ten years, at an extremely high data rate. Such a dedicated communications satellite was thought to be necessary due to the vast quantity of scientific information to be sent to Earth by landers such as the Mars Science Laboratory.

Spacecraft design is a process where systems engineering principles are systemically applied in order to construct complex vehicles for missions involving travel, operation or exploration in outer space. This design process produces the detailed design specifications, schematics, and plans for the spacecraft system, including comprehensive documentation outlining the spacecraft's architecture, subsystems, components, interfaces, and operational requirements, and potentially some prototype models or simulations, all of which taken together serve as the blueprint for manufacturing, assembly, integration, and testing of the spacecraft to ensure that it meets mission objectives and performance criteria.

<span class="mw-page-title-main">Space Micro Inc</span>

Space Micro Inc is an American company that designs and manufactures high-reliability space and satellite subsystems. Space Micro focuses on radiation-hardened Single Board Computers, Image Processing Computers, Software Defined Radios, Radio Frequency Transceivers and Transponders, Optical Terminals, Space Cameras, Star Trackers and Sun Sensors.

The Manned Space Flight Network was a set of tracking stations built to support the American Mercury, Gemini, Apollo, and Skylab space programs.

MightySat-2.1, also known as P99-1 or Sindri was a small spacecraft developed by the Air Force Research Laboratory to test advanced technologies in imaging, communications, and spacecraft bus components in space.

The European Data Relay System (EDRS) system is a European constellation of GEO satellites that relay information and data between satellites, spacecraft, UAVs, and ground stations. The first components were launched in 2016 and 2019.

<span class="mw-page-title-main">Unified S-band</span> Tracking and communication system developed by NASA and JPL

The Unified S-band (USB) system is a tracking and communication system developed for the Apollo program by NASA and the Jet Propulsion Laboratory (JPL). It operated in the S band portion of the microwave spectrum, unifying voice communications, television, telemetry, command, tracking and ranging into a single system to save size and weight and simplify operations. The USB ground network was managed by the Goddard Space Flight Center (GSFC). Commercial contractors included Collins Radio, Blaw-Knox, Motorola and Energy Systems.

<span class="mw-page-title-main">Laser Communications Relay Demonstration</span> NASA payload launched in 2021

The Laser Communications Relay Demonstration (LCRD) is a NASA mission that will test laser communication in space for extremely long distances, between Earth and geosynchronous orbit.

<span class="mw-page-title-main">SpaceX CRS-3</span> 2014 American resupply spaceflight to the ISS

SpaceX CRS-3, also known as SpX-3, was a Commercial Resupply Service mission to the International Space Station (ISS), contracted to NASA, which was launched on 18 April 2014. It was the fifth flight for SpaceX's uncrewed Dragon cargo spacecraft and the third SpaceX operational mission contracted to NASA under a Commercial Resupply Services (CRS-1) contract.

<span class="mw-page-title-main">Laser communication in space</span> Communication using lasers in outer space

Laser communication in space is the use of free-space optical communication in outer space. Communication may be fully in space or in a ground-to-satellite or satellite-to-ground application. The main advantage of using laser communications over radio waves is increased bandwidth, enabling the transfer of more data in less time.

<i>Psyche</i> (spacecraft) Reconnaissance mission of the main belt asteroid 16 Psyche

Psyche is a NASA Discovery Program space mission launched on October 13, 2023 to explore the origin of planetary cores by orbiting and studying the metallic asteroid 16 Psyche beginning in 2029. NASA's Jet Propulsion Laboratory (JPL) manages the project.

<span class="mw-page-title-main">Deep Space Atomic Clock</span> Atomic clock used for radio navigation in space

The Deep Space Atomic Clock (DSAC) was a miniaturized, ultra-precise mercury-ion atomic clock for precise radio navigation in deep space. DSAC was designed to be orders of magnitude more stable than existing navigation clocks, with a drift of no more than 1 nanosecond in 10 days. It is expected that a DSAC would incur no more than 1 microsecond of error in 10 years of operations. Data from DSAC is expected to improve the precision of deep space navigation, and enable more efficient use of tracking networks. The project was managed by NASA's Jet Propulsion Laboratory and it was deployed as part of the U.S. Air Force's Space Test Program 2 (STP-2) mission aboard a SpaceX Falcon Heavy rocket on 25 June 2019.

<span class="mw-page-title-main">Lunar Laser Communication Demonstration</span> NASA laser communication system test in 2013

LADEE's Lunar Laser Communication Demonstration (LLCD) was a payload on NASA's Lunar Atmosphere and Dust Environment Explorer lunar orbiter.

<span class="mw-page-title-main">Earth Escape Explorer</span> US experimental communications satellite

Earth Escape Explorer (CU-E3) is a nanosatellite of the 6U CubeSat format that will demonstrate long-distance communications while in heliocentric orbit.

<span class="mw-page-title-main">Deep Space Optical Communications</span> Spacecraft communication system using lasers

Deep Space Optical Communications (DSOC) is a laser space communication system in operation that improved communications performance 10 to 100 times over radio frequency technology without incurring increases in mass, volume or power. DSOC is capable of providing high bandwidth downlinks from beyond cislunar space.

References

  1. ↑ Selinger, Mark (September 2014). "Demonstrating Laser Comms" (PDF). Magazine. Archived from the original (PDF) on 12 August 2015. Retrieved 8 November 2014.
  2. ↑ "NASA - Optical PAyload for Lasercomm Science". www.nasa.gov. Retrieved 11 July 2020.
  3. 1 2 "OPALS: Light Beams Let Data Rates Soar". www.jpl.nasa.gov. December 9, 2014. Retrieved 2015-10-21.
  4. ↑ "NASA's OPALS to Beam Data From Space Via Laser". www.jpl.nasa.gov. July 11, 2013. Retrieved 2020-07-11.
  5. ↑ SpaceX. "Launch Manifest". SpaceX. Archived from the original on 2020-04-06. Retrieved 2015-10-19.
  6. 1 2 3 Oaida; et al. (2017). "abstract of Optical link design and validation testing of the Optical Payload for Lasercomm Science (OPALS) system". Society of Photo-Optical Instrumentation Engineers (Spie) Conference Series. 10563. Bibcode:2017SPIE10563E..38W. doi: 10.1117/12.2304100 .
  7. 1 2 3 4 5 6 7 8 9 10 11 Abrahamson, Matthew J.; Sindiy, Oleg V.; Oaida, Bogdan V.; Fregoso, Santos; Bowles-Martinez, Jessica N.; Kokorowski, Michael; Wilkerson, Marcus W.; Jet Propulsion Laboratory/California Institute of Technology; Konyha, Alexander L.; Embry-Riddle Aeronautical University (9 May 2014). OPALS Mission System Operations Architecture for an Optical Communications Demonstration on the ISS. American Institute of Aeronautics and Astronautics. doi:10.2514/6.2014-1627. ISBN   978-1-62410-221-9.
  8. ↑ "DesktopTV - 082615_MSFC_CutIn_Opals". av.ndc.nasa.gov. Archived from the original on 2016-03-07. Retrieved 2015-11-09.
  9. 1 2 Oaida, Bogdan V.; Wu, William; Erkmen, Baris I.; Biswas, Abhijit; Andrews, Kenneth S.; Kokorowski, Michael; Wilkerson, Marcus (2014-01-01). "Optical link design and validation testing of the Optical Payload for Lasercomm Science (OPALS) system". In Hemmati, Hamid; Boroson, Don M. (eds.). Free-Space Laser Communication and Atmospheric Propagation XXVI. Vol. 8971. pp. 89710U–89710U–15. doi:10.1117/12.2045351 . Retrieved April 8, 2023.
  10. 1 2 3 4 "Space, Stars, Mars, Earth, Planets and More - NASA Jet Propulsion Laboratory". phaeton.jpl.nasa.gov. Archived from the original on 2015-10-15. Retrieved 2015-10-21.
  11. ↑ "NASA Beams 'Hello, World!' Video from Space via Laser". www.jpl.nasa.gov. 6 June 2014. Retrieved 2015-10-21.
  12. 1 2 Wright, M. W.; Jet Propulsion Laboratory/California Institute of Technology; Tang, R. R.; NuphotonTechnologies, Inc (2014-10-10). "Qualification Testing of Fiber-Based Laser Transmitters and On-Orbit Validation of a Commercial Laser System" (PDF). International Conference on Space Optics. Retrieved 8 November 2015.
  13. 1 2 3 4 5 6 7 8 Abrahamson, Matthew J.; Oaida, Bogdan V.; Sindiy, Oleg; Biswas, Abhijit (2015-01-01). "Achieving operational two-way laser acquisition for OPALS payload on the International Space Station". In Hemmati, Hamid; Boroson, Don M. (eds.). Free-Space Laser Communication and Atmospheric Propagation XXVII. Vol. 9354. pp. 935408–935408–21. doi:10.1117/12.2182473.
  14. ↑ EVA Checklist, STS-121. Johnson Space Center. 2006. pp. 20–22.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.