40m de diámetro del Observatorio Astronómico Nacional en Yebes

I spoke this morning with Mars Express Project Scientist Olivier Witasse, who explained details on an unofficial - but very cool! - radio science tracking activity being conducted by the JIVE (Joint Institute for Very Long Baseline Interferometry in Europe) Institute.

This project is an excellent addition to the 'official' radio science tracking campaign organised by ESA using a number of ESA and NASA ground stations and centred on use of the 70m Deep Space Network station at Robledo, Spain, later this evening during closest approach.

Olivier says that scientists and engineers from JIVE learned about the Phobos flyby campaign and promptly organised a radio tracking campaign of their own, using three stations: Metsahovi (14m, Helsinki, Finland), Wettzell (20m, Munich, Germany) and Yebes (40m, Madrid, Spain).

"JIVE tracking will run for 2 hours around 21:00 UT tonight," says Olivier. "The goal is to record Mars Express signal Doppler with these three stations as an enhancement to ESA's own tracking."

NASA's big dish at Robeledo is the biggest possible 'ear' that we can use to listen to the Mars Express radio signal. But by correlating the data captured by JIVE's smaller stations, it may be possible to extract very precise Doppler data - which is the goal of the Phobos radio science activity.

"A baseline of ~2500 km between Robledo and Cebreros and Helsinki could provide another vantage point on the Phobos-induced Doppler variation; although Metsahovi is just a 14-metre dish, they expect to obtain good Doppler accuracy," JIVE institute Sergei Pogrebenko says.

Afterwards, the JIVE team will share their results with the Mars Express project team and the MaRS radio science team.

Olivier adds: "This is a very nice contribution, very much appreciated! We know JIVE very well, as they also tracked the descent of ESA's Huygens on to Titan, back in January 2005." Here's an mp3 audio of our discussion earlier today:

(Original mp3 file is here if playback box above doesn't work)

-- Daniel