The best range for the tensile strength of overhangs is 3−15 Pa (upper limit of 150 Pa), 4−30 Pa for the shear strength of fine surface materials and boulders, and 30−150 Pa for the compressive strength of overhangs (upper limit of 1500 Pa). The different regions show a similar general pattern in terms of the relation between gravitational slopes and terrain morphology: i) low-slope terrains (0−20°) are covered by a fine material and contain a few large (>10 m) and isolated boulders ii) intermediate-slope terrains (20−45°) are mainly fallen consolidated materials and debris fields, with numerous intermediate-size boulders from <1 m to 10 m for the majority of them and iii) high-slope terrains (45−90°) are cliffs that expose a consolidated material and do not show boulders or fine materials. We estimated the tensile, shear, and compressive strengths using different surface morphologies (overhangs, collapsed structures, boulders, cliffs, and Philae’s footprint) and mechanical considerations.
We computed the gravitational slopes for five regions on the nucleus that are representative of the different morphologies observed on the surface (Imhotep, Ash, Seth, Hathor, and Agilkia), using two shape models computed from OSIRIS images by the stereo-photoclinometry (SPC) and stereo-photogrammetry (SPG) techniques. We study the link between gravitational slopes and the surface morphology on the nucleus of comet 67P/Churyumov-Gerasimenko and provide constraints on the mechanical properties of the cometary material (tensile, shear, and compressive strengths). Furthermore, the launcher theory is introduced explaining the entire reaction chain: initiation -> gas dynamics -> SARP motion.Īims. Here, an overview of the development, design and testing of the launcher is given. Due to high energy densities, pyrotechnically actuated devices ultimately reduce the overall system mass and dimensions. In order to collect enough cometary material, the launcher has to provide the required kinetic energy to the SARP. Each SAS assembly consists of a pyro-driven launcher, a Sample Acquisition and Retrieval Projectile (SARP) and a retraction system using a deployable composite boom structure. Moreover, the harpoon-based system allows for acquiring several samples from different locations on the comet maximizing the scientifc output of the mission. Since comets are low gravity objects, these techniques would require anchoring before sampling, which is not necessary here. This stand-off strategy overcomes disadvantages of systems using drills or shovels.
CORSAIR uses a harpoon-based Sample Acquisition System (SAS) with the spacecraft hovering several meters above the comet surface. It belongs to the Comet Surface Sample Return mission theme which focuses on acquiring and returning to Earth a macroscopic sample from the surface of a comet nucleus. We recommend keeping extra copies of this on-hand for kids during activities.The CORSAIR (COmet Rendezvous, Sample Acquisition, Investigation, and Return) mission is a proposal for the fourth NASA New Frontiers program. Use an Engineering Notebook page for each iteration of design. Students have the option of completing a commercial, a billboard or retail packaging as a summative assessment.Īvailable at two different learning levels, TeacherGeek Engineering Notebooks are designed to help students cycle through the Design & Engineering Process and help them innovate and invent new designs. Students will learn the 4 'Ps' of marketing - Product, Placement, Price and Promotion.
ROD LAUNCHER 2.0 HOW TO
Use the protractors and ruler to make an inclinometer to measure launch angle or to measure the wind-up of your launcher! This page is already included in your Go Guide, but you can use this link to print even more.Īdd the STEAM Market-It Challenge to any completed TeacherGeek activity to teach students how to turn their TeacherGeek design into a retail product. Use the STEM Rubric to assess any TeacherGeek project.
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