Reply to Comment on 'The case for in situ resource utilisation for oxygen production on Mars by non-equilibrium plasmas

• Type: Article in International Scientific Journal
• Date: 2018-02-06

Authors

Carlos D. Pintassilgo (Author) FEUP; Vasco Guerra (Author) Other; Tiago Silva (Author) Other; Polina Oglobina (Author) Other; Loann Terraz (Author) Other; Mário Lino da Silva (Author) Other; Luís L. Alves (Author) Other; Olivier Guaitella (Author) Other

Journal

Title: PLASMA SOURCES SCIENCE & TECHNOLOGY

Vol. 27 No. 2

Pages: 1-2

Publisher: IOP Publishing

Indexing

ISI Web of Science

Scopus

INSPEC

Scientific classification

CORDIS: Physical sciences

Other information

DOI: 10.1088/1361-6595/aaa570

Abstract (EN): Our recent paper [1] has motivated a swift comment by Gruenwald [2]. We feel the need to put in context some of the points raised in [2], as well as to express our view on the contributions from the author to the topic of oxygen production on Mars using non-equilibrium low-temperature plasmas [3-5]. Contrary to the claims in [2], the basic idea to use plasma technology for space travel in general was not first presented in [3-5] and can be traced back at least to the 1960s with the invention of the Hall thrusters [6, 7], with the first satellite powered by a stationary plasma thruster having been launched in 1971 [8, 9]. In turn, the basic idea to use plasma technology to produce oxygen for a long-term human settlement on Mars was brought forward by Outlaw et al in the 1990s [10-13], who have studied both direct current (DC) and radiofrequency (RF) discharges for this purpose. Fridman's book [14] also includes some brief remarks on the subject (pages 9, 259 and 302). In [3-5], it is indeed stated that plasma can dissociate CO2 and that this can be done on Mars. However, these works do not contain experimental, theoretical, modelling or numerical simulation studies, neither of any plasma source nor of any plasma effect. Instead, the discussion in [3-5] is limited to the presentation of four references of experiments on CO2 microwave (MW) or RF plasmas reporting dissociation rates, to suggest using on Mars the discharge type, among those four, which is reported to yield a higher dissociation rate. There is ample literature available regarding CO2 reforming 0963-0252/18/028002+02633.00 by low-temperature plasmas. The renewed interest in this subject was mostly prompted by Fridman [14], more precisely by the results displayed in fi gure 5.2 of his book, which had a huge impact in the scientific community (see e.g. [15, 16] and references therein). With respect to this, the experiments referred to in [4, 5] appear to correspond to a limited choice in a wider range of data and possibilities. Additionally, no reference is made in [4, 5] to the possible role of the vibrational excitation in the process of CO2 dissociation, a major question addressed in our paper [1] that may justify the interest of RF and MW discharges, as discussed in [14].

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 2