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available online at http://meteoritics.org (CEV) to a near-Earth object (NEO). The ideal mission profile would involve two or three astronauts on a 90 to 180 day flight, which would include a 7 to 14 day stay for proximity operations at the target NEO. This mission would be the first human expedition to an interplanetary body beyond the EarthMoon system and would prove useful for testing technologies required for human missions to Mars and other solar system destinations. Piloted missions to NEOs using the CEV would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific investigations of these primitive objects. The main scientific advantage of sending piloted missions to NEOs would be the flexibility of the crew to perform tasks and to adapt to situations in real time. A crewed vehicle would be able to test several different sample collection techniques and target specific areas of interest via extra-vehicular activities (EVAs) more efficiently than robotic spacecraft. Such capabilities greatly enhance the scientific return from these missions to NEOs, destinations vital to understanding the evolution and thermal histories of primitive bodies during the formation of the early solar system. Data collected from these missions would help constrain the suite of materials possibly delivered to the early Earth, and would identify potential source regions from which NEOs originate. In addition, the resulting scientific investigations would refine designs for future extraterrestrial resource extraction and utilization, and assist in the development of hazard mitigation techniques for planetary defense. Scientific exploration of near-Earth objects via the Orion Crew Exploration Vehicle

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The Laser Interferometer Space Antenna (LISA) mission is planned to measure gravitational waves by using a constellation of three spacecraft which stay at the points of an equilateral triangle revolving around the Sun for a period of at least five and up to 8.5 years. This mission description tells how the spacecraft are launched together and then separately transferred to their constellation positions using chemical propulsion to perform manoeuvres along the way. The paper further gives characteristics of the operational orbits (contrary to common perception, for example, the LISA configuration has no net rotation in inertial space), and discusses navigation and the effects of errors in the delivery to the constellation. The particular mission described here is the LISA Baseline 1 mission, which is based on operational orbits that minimize the average rate of change of the lengths of the arms of the triangular constellation over the five-year nominal mission. The launch period for mission described here is in December 2010, which is earlier than the launch period that will actually be used by the LISA project, so this mission must be considered only as characteristic of the mission architecture and not as a final plan.

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