Design and development of inter-satellite separation mechanism for Twin Nano satellite — STUDSAT-2
This paper describes the detailed design, development and dynamic analysis of Separation Mechanism for Twin Nano-satellite “STUDSAT-2”. The separation mechanism system is interfaced between the two nano-satellites, STUDSAT-2A and STUDSAT-2B. After the ejection from the PSLV (Polar Satellite Launch Vehicle), due to stability constraints, the satellite is required to remain composite for an estimated period of 3 orbits before separation. Developing a reliable separation mechanism to sustain the launch vehicle vibrations and the space environment is of highest importance. Different design approaches and actuation strategies have been examined to ensure a uniform separation with least disturbance due to mechanically constrained surfaces. The analytical calculation to achieve the required relative velocity of the two satellite with respect to center of mass of the composite structure is performed and same has been validated using ANSYS rigid dynamics tool. Furthermore, the tool is also used to validate structural rigidity.
STUDSAT: India's first student Pico-satellite project
In the era of development of space technology, miniaturization plays a vital role in low cost small satellite missions. 12The versatile application capabilities and low cost of Pico/Nano satellites missions make them attractive for a wide scope of space exploration projects. This paper outlines the steps involved in design, development and fabrication of a Pico-satellite ‘STUDSAT’: STUDent SATellite along with the development of ground station that is capable of communicating with STUDSAT. It elaborates upon the different subsystems in the satellite. The satellite falls in the category of pico satellites, where the mass of satellite is restricted to 1 Kg and volume to 1.1 liters. The overall dimension of the satellite is (10 × 10 × 13.5) cm. The satellite is capable of capturing images of ground resolution 90 meters at an altitude of 680 Kms. The STUDSAT was launched with ISRO's PSLV C-15 on 12th July 2010 as a secondary payload. Further, the paper elaborates on the beacon and telemetry data that were received from the satellite. The satellite mission was terminated officially after 3 months from its launch date. The paper also presents the analysis on failures that had caused early termination of STUDSAT mission.
Diversity of Electrospinning Approach for Vascular Implants: Multilayered Tubular Scaffolds
Abstract The biomimetics of biological structures found in nature remains one of the most promising approaches to engineer functional tissues from natural or synthetic biocompatible materials for the replacement of damaged or injured parts of the human body. Recently, medical therapeutic regimes have advanced into a new era, overcoming the known mechanical and biological variances that occur when using autologous or synthetic grafts. Basically, the core concept of tissue biofabrication, commonly referred to as tissue engineering, is to find out the favorable cellular microenvironments to grow a living tissue prior to clinical uses. In fact, the ability of stem cells to regenerate is controlled via signaling pathways (growth factors) and supporting materials (scaffolds) that guide the cellular activities. After the first successful experiments to fabricate polymer fibers from their solutions, Cooley proposed the use of an electric field a century ago (Cooley (US 692:631, 1902 ). The electrospinning technique has been continually developed as a fruitful polymer processing technique to draw ultrafine nonwoven fibers. Electrospun polymer fibers have been used for a wide range of technical and biotechnical applications such as filtration, organic solar cells, tissue engineering, and drug releasing implants. In this regard, this review begins with an overview about the various spinning approaches for the fabrication of polymer fibers as well as the basic principles of electrospinning process. In addition, this review will highlight vascular bypass surgery and, in particular, the needs for vascular tissue engineering. Finally, the review includes some of the latest attempts to improve the mechanical and biological properties of electrospun polymeric fibers and summarizes the challenges and prospects for the future. Lay Summary However, vascular defects are treated successfully via bypass surgical bypass grafting using autologous or synthetic vessels. The small-diameter vessels (less than 6) are often associated with high failure rate. This review reports some of the recent features that should be highlighted to fabricate an ideal graft for small-diameter vascular grafts. The review introduces multilayered conduits as an alternative approach to overcome the known mechanical and biological mismatches of single layered vascular grafts of electrospun polymers.