Technical and legal issues surrounding space debris—India's position in the UN
Abstract This article briefly presents the historical background, as seen by ISRO and India, to the growing problem of space debris. It describes the technical aspects of ISRO's activities in the field of space debris, and the grey areas in technical understanding, which may impede legal discussions. Analysis of the cost and technical aspects of reorbiting satellites from geostationary Earth orbit (GEO) is detailed, since this is an important area for India and other developing countries. The article also briefly describes ISRO's views of the applicability and relevance of the existing space treaties to a possible future legal regime for space debris. Debates are currently taking place in the UN and other multilateral fora on the subject of space debris and the situation is dynamic. The main aim of this article is to inform readers of ISRO's and India's position in the UN on the subject of space debris, in terms of its technical, political and legal aspects. Certain issues of importance from the legal point of view, though not of immediate urgency, are also discussed.
Space debris and related legal issues
Many lawyers have been working towards this objective for a number of years. I will not give a long list of them here, but simply mention the main legal forums in which contributions have been made: the International Institute of Space Law; the International Law Association (ILA), which, at its 66th Conference in Buenos Aires in 1994, drew up a draft ‘international instrument on the protection of the environment from damage caused by space debris’; the Colloquium organised by K.H. Böckstiegel in May 1988 on ‘environmental aspects of activities in outer space’, not forgetting work by ECSL, particularly the joint IISL-ECSL Colloquium, or the International Bar Association and its Committee Z. At the European level, I should also mention the Resolution adopted by the ESA Council in December 2000, an initial Resolution having been adopted in 1988.
A method of calculating fragment velocity additions for the analysis of the breakup of a launch vehicle upper stage
Abstract The estimation of velocity changes in an orbital breakup event of any space object is an important activity in the field of space debris. There are various methods described in the literature to estimate velocity additions. In one method, the normal, radial and tangential components of fragment velocity additions are estimated from the differences in semi-major axis, eccentricity and inclination with respect to those of parent object. Unfortunately, when the parent orbit has small eccentricity or the breakup occurs either near apogee or near perigee, the computation of radial component of velocity increment encounters a singularity and hence is prone to errors because of imperfect orbital element data. In another method, velocity increments are estimated from semi-major axis, eccentricity, inclination, right ascension of the ascending node and true anomaly of fragments as well as parent at the time of breakup. It is very difficult to obtain the true anomaly of the fragments at the time of breakup by propagating the element sets of debris pieces backward in time owing to uncertainties in orbital elements and drag parameters. Moreover, whenever the apogee of the fragment orbit becomes less than the perigee of the parent orbit due to various perturbations or errors, this method does not yield any solution for the radial component of the velocity increment. In this paper, first, a linear method is described to estimate the components of velocity addition, utilizing relations involving the differences in semi-major axis, eccentricity, inclination and argument of perigee in a particular combination and sequence, which avoids the singularity in the computation. Later, a fully nonlinear method to obtain velocity additions without any assumption is presented, which is found to be superior to any of the methods described in the literature so far.