A first demonstration of Mars crosslink occultation measurements

• Published in: Radio science 2015-10, Vol.50 (10), p.997-1007
• Main Authors: Ao, C. O., Edwards Jr, C. D., Kahan, D. S., Pi, X., Asmar, S. W., Mannucci, A. J.
• Format: Article
• Language: English
• Subjects: crosslink; electra; Ionosphere; Mars; MRO; Odyssey; radio occultation; Space exploration
• ISSN: 0048-6604; 1944-799X
• DOI: 10.1002/2015RS005750

A series of three crosslink occultation experiments have been acquired between the Mars Odyssey and Mars Reconnaissance Orbiter spacecraft to probe the Martian atmosphere in 2007. While crosslink occultations between Earth‐orbiting satellites have been used to profile the Earth's atmosphere and ionosphere since 1995, this represents the first demonstration of crosslink occultation measurements at another planet. These measurements leverage the proximity link telecommunication payloads on each orbiter, which are nominally used to provide relay communication and navigation services to Mars landers and rovers. Analysis of the observed Doppler shift on each crosslink measurement reveals a clear signature of the Martian atmosphere, primarily the ionosphere. Inversion of the observed Doppler data yields vertical profiles of the Martian refractivity and electron density. The electron density profiles show the presence of two layers with peak densities and peak heights that are consistent with empirical model results. Our study demonstrates the feasibility and future potential of the crosslink radio occultation technique in the exploration of planetary atmospheres. Key Points Radio occultations between Mars orbiters were acquired for the first time Our analysis shows clear signatures of Martian ionosphere and atmosphere Our analysis demonstrates the feasibility and potential of this technique