Engineering topics
Berner, Jeff
Publications and source records attributed to Berner, Jeff.
NASA Deep Space Network Commitments for Human Missions to the Moon and Beyond
NASA’s Deep Space Network (DSN) serves as a critical element in the exploration of deep space, typically supporting 30-40 operational missions at any given time, each with unique characteristics and telecommunications requirements. In order to meet the needs of its diverse customer base, DSN relies on the Mission Support Definition and Commitments Office to interface with its customers and to develop, negotiate, and document the appropriate service commitments to meet each mission’s needs. Members of this office provide the needed support throughout each mission’s lifetime. While DSN’s primary focus in recent years has been supporting scientific missions by robotic spacecraft deployed across the solar system, the network is ramping-up to provide support for human spaceflight (HSF) endeavours to the moon and beyond, starting with the Artemis missions which aim to land humans on the lunar surface in the 2020’s. These HSF missions pose unique challenges for the DSN, including technical, operational, and programmatic concerns. Examples of challenges in each of these areas are provided, along with descriptions of how they are being addressed and open issues remaining.
NASA Deep Space Network Commitments for Human Missions to the Moon and Beyond
No abstract provided
NASA Deep Space Network Commitments for Human Missions to the Moon and Beyond: Paper 1530
No abstract provided
Deep Space Network - Paradigm Changes for Cost-Efficiency
This paper describes these paradigm changes, quantifies the cost reductions, and identifies the careful monitoring to assure that technical performance is maintained.
Tracking-Data-Conversion Tool
Object Oriented Data Technology (OODT) is a software framework for creating a Web-based system for exchange of scientific data that are stored in diverse formats on computers at different sites under the management of scientific peers. OODT software consists of a set of cooperating, distributed peer components that provide distributed peer-topeer (P2P) services that enable one peer to search and retrieve data managed by another peer. In effect, computers running OODT software at different locations become parts of an integrated data-management system.
The JPL Deep Space Network Simplification Project (NSP): lessons learned 1998-2004
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Reduction of Phase Ambiguity in an Offset-QPSK Receiver
Proposed modifications of an offset-quadri-phase-shift keying (offset-QPSK) transmitter and receiver would reduce the amount of signal processing that must be done in the receiver to resolve the QPSK fourfold phase ambiguity. Resolution of the phase ambiguity is necessary in order to synchronize, with the received carrier signal, the signal generated by a local oscillator in a carrier-tracking loop in the receiver. Without resolution of the fourfold phase ambiguity, the loop could lock to any of four possible phase points, only one of which has the proper phase relationship with the carrier. The proposal applies, more specifically, to an offset-QPSK receiver that contains a carrier-tracking loop like that shown in Figure 1. This carrier-tracking loop does not resolve or reduce the phase ambiguity. A carrier-tracking loop of a different design optimized for the reception of offset QPSK could reduce the phase ambiguity from fourfold to twofold, but would be more complex. Alternatively, one could resolve the fourfold phase ambiguity by use of differential coding in the transmitter, at a cost of reduced power efficiency. The proposed modifications would make it possible to reduce the fourfold phase ambiguity to twofold, with no loss in power efficiency and only relatively simple additional signal-processing steps in the transmitter and receiver. The twofold phase ambiguity would then be resolved by use of a unique synchronization word, as is commonly done in binary phase-shift keying (BPSK). Although the mathematical and signal-processing principles underlying the modifications are too complex to explain in detail here, the modifications themselves would be relatively simple and are best described with the help of simple block diagrams (see Figure 2). In the transmitter, one would add a unit that would periodically invert bits going into the QPSK modulator; in the receiver, one would add a unit that would effect different but corresponding inversions of bits coming out of the QPSK demodulator. The net effect of all the inversions would be that depending on which lock point the carrier-tracking loop had selected, all the output bits would be either inverted or non-inverted together; hence, the ambiguity would be reduced from fourfold to twofold, as desired.
Secure voice for mobile satellite applications
The initial system studies are described which were performed at JPL on secure voice for mobile satellite applications. Some options are examined for adapting existing Secure Telephone Unit III (STU-III) secure telephone equipment for use over a digital mobile satellite link, as well as for the evolution of a dedicated secure voice mobile earth terminal (MET). The work has included some lab and field testing of prototype equipment. The work is part of an ongoing study at JPL for the National Communications System (NCS) on the use of mobile satellites for emergency communications. The purpose of the overall task is to identify and enable the technologies which will allow the NCS to use mobile satellite services for its National Security Emergency Preparedness (NSEP) communications needs. Various other government agencies will also contribute to a mobile satellite user base, and for some of these, secure communications will be an essential feature.