Chandrayaan-2: A Memorable Mission Conducted by ISRO

Aims: The Chandrayaan-2 aims to wave the Indian flag on the dark side (South Pole) of the Moon that had never been rendered by any country before. The mission had conducted to gather more scientific information about the Moon. There were three main components of the Chandrayann-2 spacecraft- an orbiter, a lander, and a rover, means to collect data for the availability of water in the South Pole of the Moon. Place and Duration of Study: The rover (Pragyan) was designed to operate for one Lunar day that is equivalent to 14 Earth days, whereas the orbiter is assumed to orbit the Moon for seven years instead of the previously planned for just one year. Overview: The Chandrayaan-2 spacecraft launched by India's heavy-lift rocket Geosynchronous Satellite Launch Vehicle-Mark III (GSLV MKIII) from the Satish Dhawan Space Center launch pad located on Sriharikota island of Andhra Prades. Unlike, Chandrayaan-1, this lunar mission aimed to perform a soft-landing on the South Pole of the Lunar surface and do scientific experiments with the help of the rover (Pragyan). Reason: The Chandrayaan-1, the first lunar mission of ISRO that detected water molecules on the Moon. The Chandrayaan-2 was a follow-on mission of Chandrayaan-1 to explore the presence of water molecules on the South Pole of the Moon. Conclusion: Although the orbiter fulfilled all of the command, unfortunately, the lander (Lander) lost its communication at the last moment to touch the Moon’s surface softly. Despite that, India again showed its potential in space missions. Chandrayaan- 2 was the most low budget lunar mission ever conducted by any space organization. The developing or even underdeveloped countries may come forward in their space program as ISRO is showing a convenient way in space missions.

Roll Amplification of Solid Rocket Motor in LAPAN Sounding Rocket

Sounding rockets have been used for scientific research and implemented in meteorological and upper atmosphere studies since the late 1950s. Sounding rockets are sub-orbital carriers that follow a parabolic trajectory from launch to landing. Supporting the roadmap of Satellite Launch Vehicle development, LAPAN had launch The Sounding Rocket Program. A sensitive amplification from the production of an unpredicted roll rate was detected during the boost of the sounding rocket, despite of the tail wings in cruciform configuration at last flight test. One of this phenomenon can be influenced by the flow field of the combustion chamber during boosting time. The basic idea of this research is to model the roll amplification effect as a swirling motion of portion of exhaust gas that participate to the rotation dynamics of the rocket rather than to exit immediately flow the combustion chamber. Available flight data where is obtained from last flight test presented. It is shown the presence of a significant roll amplification when solid rocket motor is used during burning time. The result has a good agreement to presence of a portion of exhaust gas influence an unpredicted roll amplification.

Robust Optimum Trajectory Design of a Satellite Launch Vehicle in the Presence of Uncertainties

In this paper, a robust optimization method is developed to solve the Satellite Launch Vehicle (SLV) trajectory design problem in the presence of uncertainties. Given these uncertainties in the actual SLV ascent trajectory, it is important to find an optimal trajectory that is resistant to these uncertainties, as it results in increased flight performance, reduced steering-control system workload and increased SLV reliability. For this purpose, the optimization problem is first considered by applying to maximize the payload mass criterion as an objective function and three-dimensional equations of motions as the governing constraints. Then by adding mean and standard deviation parameters of uncertainties, the robust optimizer model is developed and the genetic algorithm is used to execute the model. Monte Carlo simulation is also used to analyze the results of uncertainties and its continuous feedback to the optimizer model. Finally, an optimal trajectory is obtained that is robust to the uncertainties effects such as aerodynamic coefficients, dry mass and thrust errors of the SLV. The results of the simulation show the validity of this claim.

Iran will seek solid-fuel tech for space and missiles

Significance The Nur satellite was lifted by the two-stage Qased satellite launch vehicle (SLV) into orbit 425 kilometres from earth. This followed a second failed launch in February by the civilian arm of the space programme, which first succeeded in sending a small satellite into orbit in 2009. Although Tehran is still far from possessing a regular launch capability and US Space Command described the satellite as just “a tumbling webcam in space”, US, UK and French officials criticised the move, arguing that the technology could be used to advance Iran’s ballistic missile programme. Impacts US hawks will capitalise on the launch to argue that US adversaries are developing space capabilities that must be countered. Tehran is likely soon to develop cruise missiles finally approaching the 2,000-kilometre range threshold. Iran will focus on fielding missiles with smaller bodies, more manoeuvrable warheads, higher re-entry speeds and lower observability.

Tuning Techniques Evaluation for Satellite Launch Vehicle Attitude Controllers

This communication presents a comparative analysis of tuning techniques for satellite launch vehicle attitude controllers. The investigated tuning techniques consist in the minimization of specific performance indexes, namely the Integral Absolute Error (IAE) index, the Integral of Time Multiplied Absolute Error (ITAE) index, the Integral Squared Error (ISE) index, and the Integral of Time Multiplied Squared Error (ITSE) index, being hence, termed optimal. By defining adequate figures of merit, relevant for evaluating the overall performance of satellite launch vehicles, and also taking into account requirements related to the physical limitations of the latter, the performance of attitude controllers tuned by the investigated techniques is compared to the one tuned by the methodology currently employed in the Brazilian Satellite Launch Vehicle (VLS), namely, the Linear Quadratic (LQ) methodology. Through simulation results, it is demonstrated that, despite sparse benefits produced by the alternative tuning techniques, in particular ​ITAE and ISE, the LQ methodology remains globally superior.