Speaker
Mrs
PARVATHI SP
(INDIAN INSTITUTE OF SPACE SCIENCE AND TECHNOLOGY)
Description
The preliminary design of interplanetary direct transfer trajectories is generally done using the patched conic technique. This design consists of hyperbolic excess velocity vectors at both the ends, say Earth and Mars. For an orbiter mission, a particular inclination and periapsis altitude of the approach hyperbola must be achieved. For a given departure date and a fixed flight duration, there are two hyperbolic transfer trajectory options at each end that matches the excess velocity vector for a specified inclination. Further, each of the two Earth side options can be mapped to each of the Mars side options, thus resulting in four distinct hyperbolic transfer trajectories. Two iterative analytical techniques that generate four distinct design options are introduced in this paper. The iterative analytical techniques are based on the concepts of patched conic and pseudostate methods. The distinct design options are achieved using an analytical tuning strategy. This strategy arrives at suitable hyperbolic orbit characteristics that achieves the excess velocity vector after certain duration, which is a fraction of the total flight duration, in the departure phase.
The iterative method based on patched conic technique considers the gravity field of the planet alone within its sphere of influence and that of the Sun alone outside. So, the design obtained by this technique results in large deviations in the target parameters such as the closest approach altitude (CAA) and the related time on numerical propagation under a realistic force model. To improve the achievable accuracies on the target parameters, an iterative method based on pseudostate technique is used and an improved design is generated. A comparison on the deviations in the target parameters that are obtained upon numerical propagation of these designs under similar force model is made. The benefits derived while attempting numerical refinement of these analytical designs are quantified.
| Applicant type | First author |
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Primary author
Mrs
PARVATHI SP
(INDIAN INSTITUTE OF SPACE SCIENCE AND TECHNOLOGY)
Co-author
Dr
RAMANAN RV
(Indian Institute of Space Science and Technology)
