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DTN Congestion Control
Published in Aloizio Pereira da Silva, Scott Burleigh, Katia Obraczka, Delay and Disruption Tolerant Networks, 2019
Aloizio P. Silva, Scott Burleigh, Katia Obraczka
For example, in an interplanetary network supporting Earth-Mars communication (as illustrated in Figure 10.4), the RTT is around 8 minutes when both planets are closest to one another, with a worst-case RTT of approximately 40 minutes. In this scenario, the terrestrial satellite is connected to an Orbital International Station (OIS) in orbit around the Sun, which in turn connects to a Martian satellite and a space probe. Additionally, there is a Martian terminal connected to the Martian Satellite. The link between the OIS and the Martian Satellite is interrupted whenever the planet Mars is between the OIS and the orbiting satellite, as well as whenever the Sun is between Mars and the OIS. Therefore, traffic on the “link” between the Terrestrial and Martian satellites may need to be buffered at the OIS for long and varying periods of time. If the OIS becomes heavily congested, it will significantly hamper communication between the Terrestrial satellite and the space probe.
Optomechanical Design Process
Published in Daniel Vukobratovich, Paul Yoder, Fundamentals of Optomechanics, 2018
Daniel Vukobratovich, Paul Yoder, David M. Stubbs, Kevin A. Sawyer, David Aikens
Two of the most important inputs to the design process are the performance specification and the definition of externally imposed constraints. The former sets forth the prospective user’s definition of what the end item must do and how well it must work to be judged acceptable, whereas the latter defines the physical limitations, such as size, weight, configuration, environment, and resource consumption, that affect optical, mechanical, and electrical interfaces with the surroundings. In the case of a scientific payload for a space probe, these generally would consist of many separate, complex, and lengthy documents. In the simplest cases, the specification could consist of one much shorter document giving a few general requirements. Parameters, in this case, would be left to the discretion of the optical and mechanical designers and engineers. In almost all cases, the preparation of at least one drawing to specify the optomechanical interfaces of the item would be appropriate.
Opto-Mechanical Design Process
Published in Paul Yoder, Daniel Vukobratovich, Opto-Mechanical Systems Design, 2017
Paul R. Yoder, David M. Stubbs, Kevin A. Sawyer, David Aikens
Two of the most important inputs to the design process are the performance specification and the definition of externally imposed constraints. The former sets forth the prospective user’s definition of what the end item must do and how well it must work in order to be judged acceptable, whereas the latter defines the physical limitations, such as size, weight, configuration, environment, and resource consumption that affect optical, mechanical, and electrical interfaces with the surround. In the case of a scientific payload for a space probe, these generally would consist of many separate, complex, and lengthy documents. In the simplest cases, the specification could consist of one much shorter document giving a few general requirements. Parameters would, in this case, be left to the discretion of the optical and mechanical designers and engineers. In almost all cases, the preparation of at least one drawing to specify the item’s opto-mechanical interfaces would be appropriate.
Visualization of Flow Patterns in Closed Loop Flat Plate Pulsating Heat Pipe Acting as Hybrid Thermosyphons under Various Gravity Levels
Published in Heat Transfer Engineering, 2019
Vincent Ayel, Lucio Araneo, Pietro Marzorati, Cyril Romestant, Yves Bertin, Marco Marengo
The Pulsating Heat Pipe (also called Oscillating Heat Pipe) is recently acquiring an increasing interest due both to the fascination for the complexity of the internal two-phase phenomena, and to novel applications, rapidly increasing the Technology Readiness Level of this device, both for ground and space environment. Especially looking at the potential application in space, even if a practical implementation on a satellite or a space probe is still ahead in the future, the analysis of the thermo-fluid-dynamics in various regimes and in transient gravity condition is at the base of a major development of modeling and numerical techniques, which may help the understanding of the physics of other systems, like thermosyphons or grooved heat pipes.