Mapping the Effects of Earth’s Gravity Field on the Orbit Propagation of GTO Spacecraft: A study within the context of passive de-orbiting through the use of perturbations

Mapping the Effects of Earth’s Gravity Field on the Orbit Propagation of GTO Spacecraft: A study within the context of passive de-orbiting through the use of perturbations

Srongprapa, P.

Noomen, R. (mentor)

Aerospace Engineering

Earth Observation and Space Systems

Space Flight

2015-12-18

A geostationary transfer orbit (GTO) is typically used to inject spacecraft into the geosta- tionary orbit. There are many inoperative launcher upper stages and other fragments or- biting in GTOs. These parts collide and disintegrate, becoming even smaller fragments and thereby worsening the problem of space debris. The objects could also collide with op- erational spacecraft. For this reason, a cost-effective method to de-orbit launcher upper stages from GTOs after their end-of-life is needed. Passive de-orbiting using orbital pertur- bations is one such method. A previous work performed at the University of Southampton proposed the use of luni-solar perturbations and secular effects of Earth’s gravity field for passive de-orbiting from highly elliptical orbits (HEOs). A particular type of perturbation not yet investigated in the study of perturbations-enhanced de-orbiting is the periodic ef- fects in the spherical harmonics of Earth’s gravity field model. The thesis work is focused on studying the effect of the gravitational field of Earth (rep- resented by spherical harmonics) on the long-term evolution of upper stages. First, a reli- able and validated algorithm is needed to model the complete Earth’s spherical harmonics. For this purpose, different algorithms are discussed. It is found that Cunningham’s algo- rithm is more reliable for elliptical orbits, and also more computationally efficient, than Kaula’s algorithm. However, Kaula’s algorithm is more versatile and therefore codes based on Kaula’s algorithm were developed into different programs for different types of perturba- tions. These include the secular-only perturbations, zonal harmonics, tesseral harmonics, and averaged perturbations. Although Cunningham’s algorithm was chosen for mapping due to its efficiency, the implementations of Kaula’s algorithm provide an opportunity for future research on the propagation of orbital elements. After the perturbation models had been validated, maps were created for the purpose of investigating the effects of orbital perturbations on de-orbiting. Starting with luni-solar (third-body) and J2 perturbations, the secular effects from higher-order zonal harmonics were added. This increase in the order of spherical harmonics had no significant impact on the results (the difference in perigee altitude between J2 and order 6 zonal harmonics with only secular effects is in the order of 0.5 km). On top of these perturbations, it was found that the addition of periodic effects (as opposed to having only secular effects in the Earth’s spherical harmonics model) made a small difference in the simulated perigee alti- tude. Here, the difference in the perigee altitude between the secular and periodic effects is in the order of 5 km). Not including the non-secular perturbations would lead to a more conservative prediction of lifetime. Solar radiation pressure and drag perturbations were later added to the maps. Increas- ing the area-to-mass ratio of the spacecraft would increase the impact of solar radiation pressure and drag on de-orbiting, while allowing more time for the perturbations to act could ensure that the spacecraft achieves re-entry within the simulation period. For future applications, the mapping tool will allow for the determination of optimal initial conditions for an accelerated disposal of spacecraft from GTOs and other orbits.

deorbit
space
debris
perturbations
gravity
harmonics
lifetime

http://resolver.tudelft.nl/uuid:3170c8dc-d5b6-4d01-a03e-6b13cc2c5d1b

Student theses

master thesis

(c) 2015 Srongprapa, P.