Alien audio: Listen to Mars Express skim by Phobos

An excellent result from the dedicated efforts of amateur* radio astronomer Bertrand Pinel, who lives near near Castelnaudary, France.

This sound file is a transposed version of the Doppler signal transmitted at radio frequencies by Mars Express on 29 December as it sped past Phobos. Its orbit was altered a tiny amount due to Phobos' (tiny) gravity, and this was reflected in the Doppler shift, which you can hear.

Bertrand says: "For the 29 December Phobos flyby, the favourable view over the horizon from my [home] station towards Mars was ideal to attempt recording the MEX X-Band radio signals."

Bertrand Pinel's 3.5m backyard antenna. Image credit: B. Pinel

Bertrand Pinel's 3.5m backyard antenna. Image credit: B. Pinel

The 'station' he refers to is his home-built 'satellite tracking station'.

It comprises an old HP network analyser and spectrum analyser, two Rubidium atomic clocks, a Wandel and Goltermann Selective Level Meter and a 3.5m dish antenna salvaged from the Aussagel tracking station (Issus-Aussagel, near Toulouse) when CNES decommissioned it.

He sent in the audio recording, acquired around 07:20 GMT (08:20 CET) on 29 December, together with a number of screen shots from his spectrum analyser, showing his (excellent) results tracking the Mars Express Phobos flyby (click on link below for images in the full post).

He writes:

Le fichier Audio est l 'authentique signal radio du satellite Mars Express au cours de la manoeuvre. On notera que le récepteur doit être recalé 2 ou 3 fois , causé par un effet Doppler important  (et mesurable).

The audio file is the authentic Mars Express satellite radio signal during the manoeuver. Note that the receiver had to be readjusted two or three times, due to the large Doppler effect (which was measurable).

Thank you, Bertrand for sharing your results (which have already been sent to the Mars Express science team). These are a wonderful New Year's present! Congratulations for an excellent effort!

Happy New Year to everyone from all of us at the MEX Blog!

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Ten years of the Planetary Fourier Spectrometer (PFS)

Today's post – part of a series of reports marking the MEX 10th anniversary – was submitted by Marco Giuranna, the Principle Investigator for the PFS instrument. Marco works at the IAPS Istituto di Astrofisica e Planetologia Spaziali (INAF), Rome - Ed.

It’s been ten years since Mars Express was launched on 2 June 2003. Ten years full of exciting moments, challenges, and beautiful memories. I could never forget that moment.

It was 10 January 2004. We were all insidem a small room at the European Space Operations Centre (ESOC), Darmstadt, Germany, in the very early morning hours. It was very cold outside, something like -10°C, or even colder. All the PIs for the various instruments were in that room, together with a couple members of each science team. I was among them, as a member of the Planetary Fourier Spectrometer (PFS) team. We were all waiting for the very first observation of Mars!

At that time, Vittorio Formisano was the PI for PFS. I was only a young student. I was responsible for the calibration of PFS; in other words, I had to transform the raw data sent by the instrument into quantitative measurements of Mars.

The room was silent, with only some whispering here and there. “Will the instrument switch on? Will it work properly?” I bet everyone was wondering the same questions.

All of a sudden: sounds of keyboards everywhere, people running around talking loudly… It took me a few seconds to realize what was going on: the first data were arriving!

We checked our data… everything was OK and PFS was working well. Everyone was so happy!

Everyone, except me.

Well, it's not that I wasn't happy. Of course I was, but an additional challenge was awaiting me: calibration.

Will the algorithms developed in the laboratory work also for Mars? I couldn’t answer that question – I was so nervous. But the moment has come. I got the data and loaded them into the software. All I had to do was to press the 'run' button… and hope for the best. Click.

“Mars is warmer than the Earth!” I shouted.

Single PFS measurement of Mars acquired during the very first set of observations around the equator, January 2004

Single PFS measurement of Mars acquired during the very first set of observations around the equator, January 2004. The signal around 1300 cm-1 gives a first estimation of the surface temperature: 285K.


Yes! The calibration was successful!

The first PFS observations of the Red Planet passed over the equator, and allowed a first estimation of the temperature of the surface there: around 285 K (~12 °C), much warmer than in Darmstadt!

I was so happy, I took a screenshot of the first calibrated measurements of PFS and sent it by email to all the Co-investigators around the world. I will never forget the expression of Vittorio. After all those years of hard work, his instrument was finally observing Mars!

Since then, PFS has collected almost two million measurements of Mars, allowing analyses of its atmospheric composition, circulation and climatology: ten years of top-quality science and exciting results. Who could imagine that a little feature observed in the PFS measurements would have led to one of the ten most important discoveries of the last years, and of Mars Express: methane on Mars!

First detection of Methane with PFS. Credit: ESA/IANF/IAPS

First detection of methane (CH4) with PFS (adapted from Formisano et al., 2004. Science 306, p1758).

PFS is still operating and will continue to monitor the Martian atmosphere for new, exciting results.

Happy Birthday, Mars Express!

Mars Express to relay first science data from Mars Curiosity

This weekend is shaping up to be a big one for ESA/NASA interplanetary cooperation!

Early on Saturday morning, 6 October, central European time, ESA's Mars Express will look down as it orbits above the Red Planet, lining up its Lander Communication System (MELACOM) antenna to point at NASA's Mars Curiosity on the surface.

Mars Express Credit: ESA

Mars Express Credit: ESA

For 15 minutes, the NASA rover will transmit scientific data up to MEX, which will store it on board for a time. Then, two hours later, MEX will line up again, this time pointing its High Gain antenna toward Earth to downlink the precious information to the European Space Operations Centre (similar in role and function to NASA/JPL, but without the glorious California weather - Ed.), Darmstadt, Germany.

ESA's first 35-metre deep-space ground station is situated at New Norcia, 140 kilometres north of Perth in Australia. The 630 tonne antenna will be used to track Rosetta and Mars Express, the latter to be launched in 2003, as well as other missions in deep space. The ground station was officially opened on 5 March 2003 by the Premier of Western Australia, Hon Dr Geoff Gallop. Credits: ESA

ESA's first 35-metre deep-space ground station is situated at New Norcia, 140 kilometres north of Perth in Australia.
Credits: ESA

The signal will be received via ESA's 35m deep space station at New Norcia, Australia, and the data will be immediately made available to NASA/JPL for routine processing.

The inter-Agency communication relay service will send, for the first time, actual scientific data from Curiosity via Mars Express; the previous relay services provided to Curiosity have transmitted either so-called 'open-loop' signals (no data decoded but did include useful radio Doppler information) during Entry, Descent, and Landing, or only housekeeping data and other basic telemetry during early surface operations.

"The command stack to order MEX to slew and point its UHF antennas towards Mars Curiosity during the overflight, to switch the MELACOM radio ON/OFF and to later perform the data download are already programmed on board Mars Express. Our spacecraft is ready to go for this weekend," Mars Express Operations Engineer Olivier Reboud told me this earlier today.

Curiosity - Robot Geologist and Chemist in One! Credit: NASA/JPL-Caltech

This artist's concept features NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or present ability to sustain microbial life. Credit: NASA/Caltech-JPL

Now here's the really interesting bit: of all the data that Curiosity might be sending up for relay via MEX (Mars Curiosity carries 10 science instruments plus a drill), it looks as though we'll be handling at least some images!

According to a note sent by NASA's Jennifer Maxwell, at JPL, yesterday, the Mars Express team are expecting to relay:

  • Two images from the Remote Micro-Imager (RMI) of the 'RockNest_3' rock acquired on Sol 57 (57 martian days since Curiosity landed, i.e. 3 October)
  • Three images acquired by the Mars Hand Lens Imager (MAHLI) system of the rock named 'Bathurst Inlet'

(See a previous view of Bathurst Inlet via the Mars Curiosity image page at JPL)

The RMI provides black-and-white images at 1024X1024 resolution in a very narrow 1.1-degree field of view. This provides images equivalent to a 1500mm lens on a 35mm camera. Wow!

'Bathurst Inlet' Rock on Curiosity's Sol 54, Close-Up View Credit: NASA/JPL-Caltech/Malin Space Science Systems

This is the highest-resolution view that the Mars Hand Lens Imager (MAHLI) on NASA's Mars rover Curiosity acquired of the top of a rock called "Bathurst Inlet." The rover's arm held the camera with the lens only about 1.6 inches (4 centimeters) from the rock. Credit: NASA/JPL-Caltech/Malin Space Science Systems

MAHLI comprises a camera mounted on a robotic arm on the Curiosity rover, which is used to acquire microscopic images of rock and soil (a typical MAHLI image resolution is a stunning 21 microns per pixel).

The weekend relay will provide further operational confirmation that Mars Express can serve as a back-up relay platform for NASA's new rover; it has already done so for NASA's other surface missions (Phoenix and the Mars Rovers, Spirit and Opportunity) in the past couple of years.

This cross-support underscores the strong cooperation between the two Agencies, who have worked diligently for a number of years to set technical and engineering standards to enable sharing data, information and telecommand links between spacecraft, networks, ground systems and ground stations, which helps reduce risk and boost back-up capabilities in both directions.

In ESA's MEX team, everyone's really looking forward to the first 'science contact' with Curiosity – which, as mentioned in a previous post by Thomas Ormston, should provide more "proof that the amazing new rover from the United States can talk with our veteran European Mars orbiter!"