Priorities in Space Science Enabled by Nuclear Power and Propulsion (2006) / Chapter Skim
Currently Skimming:
2 Engineering and Technical Issues
2 Engineering and Technical Issues
Pages 25-34
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 25... ...
ENGINEERING AND TECHNICAL ISSUES 25 2 Engineering and Technical Issues NUCLEAR REACTORS AND HUMAN EXPLORATION Propulsion Several studies over the past few decades have recognized the need for advanced propulsion to support human exploration. As early as the 1960s, Wernher von Braun and others recognized the value of a nuclear rocket for sending humans to Mars.
|
From page 26... ...
26 PRIORITIES IN SPACE SCIENCE ENABLED BY NUCLEAR POWER AND PROPULSION Testing and Reliability Nuclear reactor power and propulsion systems for human exploration missions must be qualified to a much higher level of reliability than power and propulsion systems that are intended for use by robotic missions. In the past, chemical systems such as the Space Shuttle Main Engines were tested more than 400 times on 30 engine systems to establish operational safety margins.
|
From page 27... ...
ENGINEERING AND TECHNICAL ISSUES 27 6.0 100 kWe 125 kWe 5.5 150 kWe 200 kWe 5.0 250 kWe 300 kWe kg) 4.5 (10,000 4.0 Mass 3.5 6000 s 7000 s Launch 3.0 8000 s 9000 s 2.5 Fundamental limiting curve 2.0 12 14 16 18 20 22 24 26 Total Time of Flight (years)
|
From page 28... ...
28 PRIORITIES IN SPACE SCIENCE ENABLED BY NUCLEAR POWER AND PROPULSION Transit Time 35 Representative "slow" 30 25 ears) 20 (y Time Representative 15 "fast" ansit Tr 10 Interstellar Precursor 5 Neptune + KBO Saturn/Titan moons Rendezvous Long Flight Times Short 0 25 30 35 40 45 50 55 60 65 NEP Velocity Change (km/s)
|
From page 29... ...
ENGINEERING AND TECHNICAL ISSUES 29 Launch Mass 4.5 Representative "fast" 4.0 kg) (10,000 3.5 Mass Launch Representative 3.0 aft "slow" Spacecr Interstellar 2.5 Precursor Neptune + KBO Saturn/Titan moons Rendezvous Long Flight Times Short 2.0 25 30 35 40 45 50 55 60 65 NEP Velocity Change (km/s)
|
From page 30... ...
30 PRIORITIES IN SPACE SCIENCE ENABLED BY NUCLEAR POWER AND PROPULSION TABLE 2.1 Transit Times of NEP Spacecraft to Representative Objects in the Outer Solar System NEP Transit Time NEP Transit Time Minimum/Maximum Transit Times Achieved So Far Objective 2004 Study (years) 2005 Study (years)
|
From page 31... ...
ENGINEERING AND TECHNICAL ISSUES 31 FIGURE 2.3 This sequence shows (clockwise from top left) the assembly and test firing of the Pewee nuclear-thermal rocket engine in 1968.
|
From page 32... ...
32 PRIORITIES IN SPACE SCIENCE ENABLED BY NUCLEAR POWER AND PROPULSION "rocket" thrusting, and then in a low-temperature mode for a long duration for "NEP" thrusting and/or while supplying power for the avionics, communications, and life-support systems. The bimodal operation offers the fastest trip times for high delta-V missions but will require significant testing and demonstration to validate fuel performance.
|
From page 33... ...
ENGINEERING AND TECHNICAL ISSUES 33 · Reliability and unattended operation. Reactors must operate under conditions in which communications are delayed from minutes to several hours, and be appropriately engineered for reliability and long-term drift in instruments.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.