Suborbital flights could have a better carbon footprint per passenger than transatlantic airline travel, a preliminary European Space Agency study has found.
The study, carried out by ESA's general studies department in the first quarter of this year, is expected to be followed up by more detailed work.
The preliminary work examined suborbital launch systems and compared, on a per passenger basis, their environmental impact with the carbon footprint of widebody aircraft that operate on transatlantic routes.
However ESA's researchers have declined to release the per passenger carbon footprint data from the preliminary study.
"I don't want to release our figures before we do the more detailed work," study leader Geraldine Naja-Corbin told the International Academy of Astronautics' first international symposium on private human access to space on 28 May.
Presenting ESA's new position paper on suborbital space tourism at the symposium, Naja-Corbin added that space tourism does not have a "bright future" if is not legislated for in the regulatory framework in Europe.
The suborbital transport environmental impact study followed ESA's earlier space tourism projects. In 2004 it carried out a market analysis in 2005 the agency assessed European private ventures and managed a European Union study.