Proceedings of the Workshop - United Nations Office for Outer ...

202 MAINTAINING THE SPACE ENVIRONMENTMissions of questionable benefit5The Outer Space Treaty contains in its Article I theprinciple that the exploration and use of outer spaceshall be carried out for the benefit and in the interestso f all countries, irrespective of their degree of scientificand economic development. This statement - of highmoral value - tacitly assumes that it is possible to findout what is the benefit and interest o f all countries. Inpractice, however, a benefit to one user of space maybe a detriment to someone else. E.g., commemorativemissions by conspicuous space objects reflecting lightwould indeed draw the attention o f the public butastronomers strongly object whenever their valuableand unique observations have been destroyed orcompromised by the spectacle. Another example: Asatellite illuminating fields during the night mightincrease the yield of the crop but, without a properenvironmental assessment, such practice might lead toundesirable effects, such as proliferation of rodents orto extinction of forms of life which need a daily darkperiod for survival.Although an absolutely satisfactory solution doesnot exist, it is possible, as it is done in other situations,to balance the advantages and drawbacks and to decideaccordingly. What is needed, is an institutioncompetent to consider the matter, to arrive at areasonably good solution and to make its judgmentrespected by space users. Could some cases be solvedwithin the framework of national law regulations?Would other cases require a ruling by the InternationalCourt of Justice? It is proposed to bring this point tothe attention o f UNISPACE III under the followingrecommendation:“With regard to the increasing number o fsatellites and to the necessity to maintain the spaceenvironment in a state fit fo r space activities o f futuregenerations, it is recommended to launching States toconsider, from a global point o f view, the balance o fbenefits and detriments o f planned missions and totake an appropriate decision concerning therealization or modification o f such missions.Exhaust gasesThere is no doubt that exhaust gases o f spacelaunchers pollute the atmosphere from the ground upto the altitude when the rocket engine is switched off.The question of how important is that effect wastackled by the French Academy of Sciences and theFrench National Air and Space Academy, ANAE. Astudy6 by the latter surveyed the nature of the effluentsemitted by space launchers, such as Ariane 5, thespace shuttle, or launchers using liquid oxygen.Homogeneous reactions lead to the following effects onstratospheric ozone: Local ozone is immediatelydestroyed but very soon its content is restored.Regional effects persist for several days: the chlorinelevel increases by a few percent and the ozonedepletion is less than 1%. Global effects o f 9 STS and6 Titan IV launchings per year would result in anincrease o f less than 0.25% in chlorine content of theatmosphere. The impact o f 15 Ariane 5 launches peryear would deplete the ozone level by 0.02%.Heterogeneous reactions on the surface of aerosols andaluminum particles add very little to that value.Also experiments o f rocket impact on atmosphericozone have no significant effect. And the impact ongreenhouse effect, mainly by carbon dioxide and watervapour, was found to be negligible. Summing up, thestudy concludes that quantities produced by present orfuture space launchers amount to much less thanquantities produced by other human activities or bynatural sources, such as large volcano eruptions.In this respect, the atmosphere and its constituentsare not sensitive to space activities or, for that matter,to air traffic. Natural phenomena occur on a muchlarger scale.5 For more details see L. Perek: Must space missions bebeneficial? Proc. 35th Coll. On the Law of Outer Space,Washington, AIAA, p. 303-306, 1993.6 Impact of Aircraft and Space Launchers on the Atmosphereand Climate: Recommendations, ANAE, Dossier No. 13,1998.