Space Communications - Volume 15, issue 2

Authors: Lesh, James R.

Article Type: Research Article

Abstract: The NASA‐funded optical communications program being conducted at JPL is described. The spacecraft transceiver terminal developments, a test infrastructure for assessing the performance of future space terminals, an atmospheric visibility monitoring program, some recent systems‐level demonstrations, and a communications technology roadmap for planetary missions over the next 25 years are presented.

Citation: Space Communications, vol. 15, no. 2, pp. 65-70, 1998

Authors: Lutz, Hanspeter

Article Type: Research Article

Abstract: An overview is given of the intersatellite laser communication activities of the European Space Agency (ESA), focusing on the most recent systems and hardware technology efforts aimed at realizing small and compact laser terminals for worldwide mobile communication systems and satellite‐based data networks.

Citation: Space Communications, vol. 15, no. 2, pp. 71-78, 1998

Authors: Imai, R. | Saifudin, A. | Okazawa, H. | Kadowaki, N. | Yamamoto, M.

Article Type: Research Article

Abstract: The objective of the Gigabit satellite is to provide the global high‐data‐rate communications network. The key technologies are the Ka‐band scanning sport beams, on‐board ATM switch, inter‐satellite laser link and the advanced beam control.

Citation: Space Communications, vol. 15, no. 2, pp. 79-81, 1998

Authors: Horkin, Philip R. | Olds, Keith A.

Article Type: Research Article

Abstract: The birth of large LEO constellations dedicated to personal communications in the past few years has created formidable new tasks for the space industry. Systems such as the IRIDIUM^{\scriptsize{\circledR}} Program, Globalstar^{\scriptsize{\circledR}} , and Odyssey^{\scriptsize{\mathrm{TM}}} challenge the long standing paradigm on how to design, build, and launch satellites. A second generation of big LEOs is now being planned to offer broadband services for Internet access, cellular backhaul, videoconferencing and distance learning. Systems such as Teledesic^{\scriptsize{\mathrm{TM}}} and M‐Star are planned to make extensive use of inter‐satellite links. Until now, these crosslinks have been implemented …using RF technology, but as the data rate of these systems increases, serious consideration must be given to the use of optical inter‐satellite links. Much has been discussed in the media over the past years about the relative merits of both optical and RF approaches. This paper avoids this debate, and examines the reasons that RF technology currently dominates inter‐satellite links. The cost of existing optical terminals for space has is measured in the millions to tens of millions of dollars. These figures often compare to the total on‐orbit cost of the satellites in commercial constellations. Clearly, a significant paradigm shift will be required in order for producers of optical ISLs to realize a business from these commercial satellite programs. This paper discusses both the technical and programmatic requirements of terminals for such systems in order to provide the industry a better understanding of upcoming needs and constraints essential for their success. Show more

Citation: Space Communications, vol. 15, no. 2, pp. 83-87, 1998

Authors: Wilson, K.E. | Lesh, J.R. | Araki, K. | Arimoto, Y.

Article Type: Research Article

Abstract: The Ground‐to‐Orbit Lasercom Demonstration conducted between the ETS‐VI spacecraft and the ground station at JPL’s Table Mountain Facility, Wrightwood CA was the first ground‐to‐space two‐way optical communications experiment. The demonstration was conducted over a period of seven months and required simultaneous and cooperative operations by team members in Tokyo and California. A key objective was to measure the atmospheric attenuation and seeing during the demonstration to evaluate the performance of the optical link. The optical downlink telemetry provided information on the in‐orbit performance of ETS‐VI’s laser communications equipment. Downlinked PN data enabled measurement of bit‐error rates. BERs as low as …10^{-4} were measured on the uplink and 10^{-5} on the downlink. Measured signal powers (corrected for measured atmospheric attenuation) agreed with theoretical predictions. Show more

Citation: Space Communications, vol. 15, no. 2, pp. 89-95, 1998

Authors: Pribil, K. | Krieger, J. | Meier, C. | Stolze, M. | Majewski, Th. | Müller, Th. | Pruchner, R.

Article Type: Research Article

Abstract: We describe the realization of the Lasercomm on‐ground verification system SOLACOS and the current development status. SOLACOS comprises the hardware development of 2 optical terminals and the test infrastructure to test the performance of this system in on‐ground experiments. In SOLACOS we implement a coherent 650 MBit/s transmission channel based on coherent Syncbit data transmission technology and on Nd\,{:}\, YAG solid state lasers, a diode‐laser based 10 MBit/s ASK transmission system and a fully functional PAT system for an inter‐orbit‐link application. In parallel to the hardware activities, a computer simulation model of the system is realized. The …main goal of SOLACOS is to match the predictions from the simulation to the real‐world results from the hardware. Show more

Citation: Space Communications, vol. 15, no. 2, pp. 97-104, 1998

Authors: Czichy, Reinhard H.

Article Type: Research Article

Abstract: Inter‐Satellite Links (ISL’s) will become important elements for the architecture of the future in‐orbit communications infrastructure. Various application scenarios for optical ISL’s will be discussed and the associated system/terminal requirements will be outlined. The basic design considerations influencing an optical ISL design will be recalled and some promising concepts for high data rate miniature terminals will be identified. The design of a Miniature Optical Terminal for data rates of > 1 Gbps will be presented and possible in‐orbit demonstration scenarios will be discussed.

Citation: Space Communications, vol. 15, no. 2, pp. 105-112, 1998

Authors: Koyama, Y. | Shiratama, K.

Article Type: Research Article

Abstract: Engineering Model of LUCE (Laser Utilizing Communications Equipment) is now under production in the frame of OICETS (Optical Inter‐Orbit Communications Engineering Satellite) NASDA program. Many devices and components to realize required functions of LUCE have been developed and characterized. This paper describes the design and measured performances of devices and components for LUCE EM and Optical Antenna STM.

Citation: Space Communications, vol. 15, no. 2, pp. 113-119, 1998