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The primary goal of the Genesis Mission is to collect solar wind ions and, from their analysis, establish key isotopic ratios that will help constrain models of solar nebula formation and evolution. The ratios of primary interest include 17O/16O and 18O/16O to ±0.1%, 15N/14N to ±1%, and the Li, Be, and B elemental and isotopic abundances. The required accuracies in N and O ratios cannot be achieved without concentrating the solar wind and implanting it into low-background target materials that are returned to Earth for analysis. The Genesis Concentrator is designed to concentrate the heavy ion flux from the solar wind by an average factor of at least 20 and implant it into a target of ultra-pure, well-characterized materials. High-transparency grids held at high voltages are used near the aperture to reject >90% of the protons, avoiding damage to the target. Another set of grids and applied voltages are used to accelerate and focus the remaining ions to implant into the target. The design uses an energy-independent parabolic ion mirror to focus ions onto a 6.2 cm diameter target of materials selected to contain levels of O and other elements of interest established and documented to be below 10% of the levels expected from the concentrated solar wind. To optimize the concentration of the ions, voltages are constantly adjusted based on real-time solar wind speed and temperature measurements from the Genesis ion monitor. Construction of the Concentrator required new developments in ion optics; materials; and instrument testing and handling.

This paper describes the test program in detail including test sample description, test procedures, and vibration test results of multiple test samples. The material pairs used in the experiment were Aluminum-Aluminum, Aluminum- Dicronite coated Aluminum, and Aluminum-Plasmadize coated Aluminum. Levels of vibration for each set of twelve samples of each material pairing were gradually increased until all samples experienced substantial displacement. Data was collected on 1) acceleration in all three axes, 2) relative static displacement between vibration runs utilizing photogrammetry techniques, and 3) surface galling and contaminant generation. This data was used to estimate the values of static friction during random vibratory motion when "stick-slip" occurs and compare these to static friction coefficients measured before and after vibration testing.

We have recently completed a breadboard ion-clock physics package based on Hg ions shuttled between a quadrupole and a 16-pole rf trap. With this architecture we have demonstrated short-term stability ∼1–2×10−13 at 1 second, averaging to 10−15 at 1 day. This development shows that Hmaser quality stabilities can be produced in a small clock package, comparable in size to an ultra-stable quartz oscillator required for holding 1–2×10−13 at 1 second. This performance was obtained in a sealed vacuum configuration where only a getter pump was used to maintain vacuum. The vacuum tube containing the traps has now been under sealed vacuum conditions for over three years with no measurable degradation of ion trapping lifetimes or clock short-term performance. We have fabricated the vacuum tube, ion trap and UV windows from materials that will allow a ∼ 400°C bake-out to prepare for tube seal-off. This approach to the vacuum follows the methods used in flight vacuum tube electronics, such as flight TWTA's where tube operation lifetime and shelf life of up to 15 years is achieved.

This overview paper describes the system design of the structurally-connected interferometer (SCI) concept studied for the Terrestrial Planet Finder (TPF) project. This paper covers progress since August 2003 and serves as an update to a paper presented at that month's SPIE conference, "Techniques and Instrumentation for Detection of Exoplanets". SCI trade studies conducted since mid-2003 have focused on key factors driving overall flight segment mass and performance, including launch vehicle packaging, structural design, and instrument layout. This paper summarizes the results of the recent design trades, with discussion of the primary requirements that drive the baseline design concept.

This paper describes the basic structural design of the Terrestrial Planet Finder (TPF) Structurally Connected Interferometer concept developed within the Jet Propulsion Laboratory design team. Descriptions of the key structural components, optical elements, and basic load paths are included. Key structural requirements related to launch loads and on-orbit stability and alignment are identified. The analysis results for the baseline design are shown for both launch configuration and the deployed, on-orbit configuration. The finite element models are described with preliminary results shown. Excitation of the structure and the optical train caused by assumed external disturbances are shown for a preliminary analysis. Future work is identified.

This paper discusses the fabrication considerations and proposed testing concepts for a twelve meter, graphite-epoxy space truss that is being developed to provide structural support for the primary mirror system of the SpacE Laser ENErgy (SELENE) Beam Transmission Optical System (BTOS). A general description of the mirror support configuration is presented. Specific issues which are addressed include low-cost fabrication techniques utilized in the support structure. Later, a description of the dynamic testing program for the entire active primary mirror system is outlined.

Design and fabrication of a large primary reflector structure for space laser power beamingPaul MacNeal and Ken JewettJet Propulsion Laboratory, California Institute of Technology4800 Oak Grove Drive, Pasadena, California 91109ABSTRACTThis paper discusses the design issues and fabricatiQn consideration& specifically related to a large twelve meter,graphite-epoxy space truss that has been developed to provide support of the primary mirror system for the SpacE LaserENErgy (SELENE) Beam Transmission Optical System (BTOS). Details of the optical system and wavefront correctorconcepts have been discussed in prior papers. Specific issues which are addressed in this paper include opticalperformance needs, environmental requirements, and lowcost fabrication techniques.2. INTRODUCTIONBTOS is a portion of a larger project entided SpacE Laser Electric ENErgy (SELENE). The SELENE project ismanaged by Marshall Space Flight Center and utilizes a high energy, free electron laser to transfer energy from theground to orbiting spacecraft or other targets such as a lunar colony. BTOS is the system that transmits the beamenergy from the laser to the target. BTOS receives a one meter diameter energy beam which has been cleaned up sothat the Strehl ratio is 0.9 or greater.To satisfy requirements for the SELENE missions, which include a Strehi ratio greater than 0.5

The Articulating Fold Mirror (AFM) for the Wide Field/Planetary Camera-II (WF/PC-II) instrument is a very compact, complicated, highly precise mechanism. The AFM's basic function is to provide tip and tilt correction in the optical paths of the WF/PC-II instrument. Its necessity is brought about indirectly by the spherical aberration of the primary mirror in the Hubble Space Telescope (HST). Many challenges are created by the necessity of the new mechanism in the optical design. (1) The new mechanism must exhibit high precision in the placement of the mirror surface in two rotations (tip and tilt). (2) The available packaging volume for the AFM is very shallow and requires an innovative approach to achieve the necessary performance requirements. (3) The schedule for delivery of the flight certified AFM's is extremely tight, and as such does not allow for any failures during the qualification phase of the AFM project. Structural design and analysis plays a major role in meeting the stringent performance requirements within the schedule and fiscal constraints. The final result is a qualified mechanism which meets or surpasses all of its requirements.

The paper describes the JPL study leading to a baseline design of the Beam Transmission Optical System (BTOS), designed for the delivery of laser energy from earth to space targets. The study identified the driving environmental and functional requirements; developed a conceptual design of the BTOS telescope; and performed static, thermal distortion, and model analyses to verify that these requirements are met. The study also identified major areas of concern which should be investigated further.

An effort is currently being carried out by the Jet Propulsion Laboratory (JPL) to study mission feasibility and to define functional requirements for various subsystems of the Space Infrared Telescope Facility (SIRTF). As a major part of this effort, structural design requirements have been derived based on the stated mission objectives. Design concerns addressed by these requirements include the limits on mass and location of the center of gravity, launch stiffness and dynamic characteristics, design loads and analysis criteria, survivability of the TITAN IV/Centaur launch environment, thermal control for maintaining a near absolute-zero operating temperature, and helium cryogen volume and storage for a five-year mission. To illustrate how the structural design requirements can be met, a point design of the SIRTF flight hardware system was developed, modeled, and analyzed. A description of the key features of this point design, along with pertinent modeling and analysis results, are discussed in this Paper.

To assess the design feasibility of the Space Infrared Telescope Facility (SIRTF) and to identify parameters that might impose constraints on performance such as frequencies of vibration, structural concepts for both the telescope and spacecraft are developed and evaluated. Trade studies of key design features are carried out using FEM and analysis. In most cases, the margin of safety was greater than 0.50. An example of stress in the octagonal equipment bus panels is shown. The strap-supported mass is predicted to deflect 6 mm relative to the outer shell when subjected to 8.0 G in the X direction, and to deflect about 5 mm in the Y and Z directions when subjected to 10.0 G. Deflections for the top of the solar panel are predicted to be about 35 mm when subjected to the 10.0 G quasi-static load in the Z direction. The liquid helium tank, thermal isolation, and primary mirror and mount are discussed.