NASA’s Artemis II mission includes an optical communication payload, affectionately known on board as “OpCom,” which is part of NASA’s Orion Artemis II Optical Communications (O2O) demonstration. We describe the OpCom system architecture and operations concept.
The Integrated LCRD Low-Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T) payload will be launched to the International Space Station (ISS) in 2023. ILLUMA-T is an optical communications payload that will make the ISS the first space-based user to communicate with NASA’s Laser Communications Relay Demonstration (LCRD). The system will support all-optical forward links up to 150 Mbps and return links up to 1 Gbps. The payload recently underwent system level Thermal VACuum (TVAC) functional testing at MIT Lincoln Laboratory. We present an overview of the payload’s TVAC functional tests and results.
Free-space laser communication systems are increasingly implemented on state of the art satellites for their high-speed connectivity. This work outlines a demonstration of the Modular, Agile, Scalable Optical Terminal (MAScOT) we have developed to support Low-Earth Orbit (LEO) to deep-space communication links. In LEO, the MAScOT will be implemented on the International Space Station to support the Integrated Laser Communications Relay Demonstration (LCRD) LEO User Modem and Amplifier Terminal (ILLUMA-T) program. ILLUMA-T's overarching objective is to demonstrate high bandwidth data transfer between LEO and a ground station via a geosynchronous (GEO) relay satellite. Outside of LEO, the MAScOT will be implemented on the Artemis-II mission to demonstrate high data rate optical communications to and from the moon as part of the Optical to Orion (O2O) program. Both missions leverage the same modular architecture despite varying structural, thermal, and optical requirements. To achieve sufficient performance, the terminal relies on a nested tracking loop to realize sub-arcsecond pointing across a ±120 ° elevation and ±175° azimuth field of regard.
The Laser-Enhanced Mission Communications Navigation and Operational Services (LEMNOS) office at Goddard Space Flight Center (GSFC) manages two NASA optical communication related projects, the Orion EM-2 Optical Communications Terminal (O2O) and the Integrated Laser Communications Relay Demonstration (LCRD) Low-Earth Orbit (LEO) User Modem and Amplifier Terminal (ILLUMA-T) projects. The main goal of LEMNOS is the advancement and implementation of optical communications systems and technologies for NASA missions. The O2O mission is sponsored by NASA’s Human Exploration and Operations (HEO) Mission Directorate. The O2O project will provide optical communications capability to the Orion series of spacecraft, starting with the demonstration of operational utility on EM-2. It will be the first time a human exploration mission will rely on optical communications for its high-bandwidth link. ILLUMA-T is sponsored by the Space Communications and Navigation (SCaN) Program Office. It is destined for the International Space Station (ISS) as an external payload attached to the Japanese Experiment Module - Exposed Facility (JEM-EF). The ILLUMA-T project is developing an optical communications user terminal to demonstrate high bandwidth data transfer between LEO and the ground through the geosynchronous LCRD relay. ILLUMA-T will be the first demonstration of a LEO user of the LCRD system, pointing and tracking from a moving spacecraft at LEO to GEO satellite and vice versa, end-to-end operational utility of optical communications, and 51 Mbps forward link to ISS from ground. Both projects are collaborations between GSFC, Massachusetts Institute of Technology – Lincoln Laboratory (MIT-LL), and a number of contractors.
Delivery of large volumes of data from low-Earth orbit to ground is challenging due to the short link durations associated with direct-to-Earth links. The short ranges that are typical for such links enable high data rates with small terminals. While the data rate for radio-frequency links is typically limited by available spectrum, optical links do not have such limitations. However, to date, demonstrations of optical links from low-Earth orbit to ground have been limited to ~10 to ~1000 Mbps. We describe plans for NASA’s TeraByte InfraRed Delivery (TBIRD) system, which will demonstrate a direct-to-Earth optical communication link from a CubeSat in low-Earth orbit at burst rates up to 200 Gbps. Such a link is capable of delivering >50 Terabytes per day from a small spacecraft to a single small ground terminal.
In recent years, NASA has been developing a scalable, modular space terminal architecture to provide low-cost laser communications for a wide range of near-Earth applications. This development forms the basis for two upcoming demonstration missions. The Integrated Low-Earth Orbit Laser Communications Relay Demonstration User Modem and Amplifier Optical Communications Terminal (ILLUMA-T) will develop a user terminal for platforms in low-Earth orbit which will be installed on the International Space Station and demonstrate relay laser communications via NASA’s Laser Communication Relay Demonstration (LCRD) in geo-synchronous orbit. The Orion EM-2 Optical Communication Demonstration (O2O) will develop a terminal which will be installed on the first manned launch of the Orion Crew Exploration Vehicle and provide direct-to-Earth laser communications from lunar ranges. We describe the objectives and link architectures of these two missions which aim to demonstrate the operational utility of laser communications for manned exploration in cislunar space.
In October 2013 the Lunar Laser Communications Demonstration (LLCD) made communications history by successfully demonstrating 622 megabits per second laser communication from the moon’s orbit to earth. The LLCD consisted of the Lunar Laser Communication Space Terminal (LLST), developed by MIT Lincoln Laboratory, mounted on NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft and a primary ground terminal located in New Mexico, the Lunar Laser Communications Ground Terminal (LLGT), and two alternate ground terminals.
This paper presents the optical layout of the LLST, the approach for testing the optical subsystems, and the results of the optical qualification of the LLST. Also described is the optical test set used to qualify the LLST. The architecture philosophy for the optics was to keep a small, simple optical backend that provided excellent boresighting and high isolation between the optical paths, high quality wavefront on axis, with minimal throughput losses on all paths. The front end large optics consisted of a Cassegrain 107mm telescope with an f/0.7 parabolic primary mirror and a solar window to reduce the thermal load on the telescope and to minimize background light received at the sensors.
KEYWORDS: Navigation systems, Laser communications, Telecommunications, Data communications, Satellites, Clocks, Phase measurement, Receivers, Space operations, Global Positioning System
The Lunar Laser Communication Demonstration (LLCD) flown on the Lunar Atmosphere and Dust Environment Explorer (LADEE) satellite achieved record uplink and downlink communication data rates between a satellite orbiting the Moon and an Earth-based ground terminal. In addition, the high-speed signals of the communication system were used to accurately measure the round-trip time-of-flight (TOF) of signals sent to the Moon and back to the Earth. The measured TOF data, sampled at a 20-kS/s rate, and converted to distance, was processed to show a Gaussian white noise floor typically less than 1 cm RMS. This resulted in a precision for relative distance measurements more than two orders-of-magnitude finer than the RF-based navigation and ranging systems used during the LADEE mission. This paper presents an overview of the LLCD TOF system, a summary of the on-orbit measurements, and an analysis of the accuracy of the measured data for the mission.
KEYWORDS: Space operations, Space telescopes, Laser communications, Telescopes, Data communications, Clouds, Time division multiplexing, Video, Multiplexing, Laser systems engineering
From mid-October through mid-November 2013, NASA’s Lunar Laser Communication Demonstration (LLCD) successfully demonstrated for the first time duplex laser communications between a satellite in lunar orbit, the Lunar Atmosphere and Dust Environment Explorer (LADEE), and ground stations on the Earth. It constituted the longest-range laser communication link ever built and demonstrated the highest communication data rates ever achieved to or from the Moon. The system included the development of a novel space terminal, a novel ground terminal, two major upgrades of existing ground terminals, and a capable and flexible ground operations infrastructure. This presentation will give an overview of the system architecture and the several terminals, basic operations of both the link and the whole system, and some typical results.
Array-based architectures for deep-space photon counting lasercom links offer a powerful mechanism to
lower the cost and improve the scalability of Earth- or space-based optical receivers. In this architecture, a
large area receive telescope is constructed by using an array of small, inexpensive telescopes that are
networked together. However, a limitation on how many small telescopes can be used comes from the
minimum SNR requirement for synchronization. In general, the synchronization requirements are not difficult
to meet for systems with enough SNR to achieve >Mbps performance. However, deep-space links often have
large variations in their operational parameters due to varying link distances from orbital considerations as
well as atmospherics. If the system is required to operate under such stressing conditions, albeit with a low
(100's of Kbps) data rate, it is important to consider required SNR for synchronization as a design parameter.
Furthermore, for very remote systems (e.g. beyond Mars), expected data rates may only be 100's of Kbps, in
which case synchronization will be a critical design parameter. In this paper, we will examine the design trade
space between number of arrayed telescopes and synchronization parameters. We will focus on the low SNR/
low data rate case as it is the most stressing.
A systems-level analysis of a high data rate Mars to Earth optical communications link is presented. A feasibility of a minimum 10 Mb/s optical link with the possibility of achieving > 100 Mb/s under certain conditions will be shown. The link design employs a Pulse Position Modulated (PPM) 1.06 μm Mars transmitter with a photon-counting Earth receiver. This study will characterize system performance (link data rate) as a function of orbital position including the complex diurnal and annual variations in the Mars-Earth system. Key system impairments that vary diurnally/annually include loss and turbulence due to the Earth's atmosphere, daytime/nighttime sky background noise, background noise from Mars itself, and space loss due to the relative planetary distances. In addition, transmitter/receiver design parameters and their impact on system performance are discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.