Saturday evening update from the MEX team

This sent in from Andy Johnstone at ESOC, ESA's Space Operations Centre in Darmstadt, just a few minutes ago.

Everything is running smoothly at the moment! James Godfrey and I have been at ESOC since about 17:00GMT (18:00 local); I will stay on through the night and he will come back in with Erhard Rabenau at around 06:00GMT (07:00CET) on Sunday morning.

Acquisition of signal by ESA's New Norcia ground tracking station was on time today at 18:19GMT (19:19 CET) via both X- and S-Band frequencies.

This animation shows the flyby on 29 Dec 2013 (speeded up) as if you were standing on Phobos, with Mars in the background and Mars Express sweeping out an arc above. Toward the end of the sequence, Mars Express disappears behind Mars and out of sight of Phobos. Thanks to the MEX team and Simon Wood at ESOC for generating this!

We have had our first period where we switch off the telemetry modulation [that is, downloading information from MEX] and only receive a carrier signal [just a raw radio signal] from the spacecraft.

Setting Mars Express to transmit carrier only increases the strength and quality of the signal, which therefore gives us better radio science, But this is always a worrying period for the Flight Control Team as we cannot tell what is happening on board the spacecraft. All we have to go on during these periods is a spectrum analyser and a display from the ground station saying that a signal is still being detected.

The next scheduled event will be loss of signal at 00:25GMT (01:25CET) when Mars Express passes behind Mars; it will reappear at the end of this occultation at 00:53GMT (01:53CET). This in itself is a good opportunity for radio science as our scientists can obtain information on Mars' atmosphere by the way the radio signal is affected as it briefly passes through en route to Earth.

We are looking forward to a quiet night with everything running as planned!

Best regards

-- Andy Johnstone
Spacecraft Operations Engineer, TT&C, Mars Express

 

 

First Contact! Mars Express’ first ‘conversation’ with Curiosity

As we reported yesterday, Mars Express had a busy Sunday evening, pointing first at NASA's Curiosity rover on the surface of Mars and then swinging around to do another relay pass with Opportunity. We received the data from both of these passes this morning over ESA's New Norcia ground station and, on first look, it seems that both relays were very successful.

First Laser-Zapped Rock on Mars

First Laser-Zapped Rock on Mars. This composite image, with magnified insets, depicts the first laser test by the Chemistry and Camera, or ChemCam, instrument aboard NASA's Curiosity Mars rover. The composite incorporates a Navigation Camera image taken prior to the test, with insets taken by the camera in ChemCam. The circular insert highlights the rock before the laser test. The square inset is further magnified and processed to show the difference between images taken before and after the laser interrogation of the rock. The test took place on Aug. 19, 2012. Credit: NASA/JPL-Caltech/LANL/CNES/IRAP

In ESA's MEX team, we're particularly excited to have had our first contact with Curiosity – proof that the amazing new rover from the United States can talk with our veteran European Mars orbiter!

At the start of the contact, Mars Express was over 3600 km from Curiosity's landing site in Gale Crater and closed in to only 1300 km by the end of the contact – streaking across the sky as seen from Curiosity.

During this overflight by Mars Express, it 'hailed' Curiosity in Gale Crater and the rover responded. The two spacecraft then autonomously established a link with each other and Curiosity flowed data back to Mars Express for nearly 15 minutes. This international chat between two spacecraft in deep space is proof of all our preparation, standardisation and cooperation work in action – so it's something both agencies can be proud of.

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. 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

The actual data that flowed back was made available to NASA earlier today, who will now retrieve and process the data.

Hopefully we'll have some info from them in the next couple of days about what exactly was contained within. We'll also receive (within Tuesday) the 'housekeeping' telemetry of Melacom – information on how our radio performed. This will allow us to double-check the performance of this first important contact with Curiosity.

The data was sent at a rate of only 8 kbps – 125 times slower than the 1-Mbit/second Internet connection you might have at home!

We wanted to take things easy to start with, though, and test the performance of the link. Nonetheless, we received 955 data packets from Curiosity, totalling 867 kilobytes of data.

This will be the first of several contacts with Curiosity in the future, as we better learn how to use and optimise this relay link between the two craft and the two space agencies. Watch this space for more details as we get them on this pass and the future contacts between Mars Express and Curiosity.

 

Nice note from NASAs’ MSL Mission Interface Manager

Curiosity rover descending under parachute to martian surface, as seen by NASA Odyssey Credit: NASA/JPL-Caltech/Univ. of Arizona

PASADENA, Calif. – An image from the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance orbiter captured the Curiosity rover still connected to its almost 16-meter-wide parachute as it descended toward Gale Crater.

This note came in last night from Susan Kurtik, NASA's MSL Mission Interface Manager at JPL and the person with whom ESA's ESTRACK team at ESOC worked to plan and conduct the tracking of MSL's arrival using New Norcia station (see our earlier post – ESA, NASA, Parkes: Big ears on Earth will listen to MSL descend – Ed.)

Susan wrote:

 

We want to extend our Congratulations for the incredible success of the ESA MEX and ESTRACK support of the MSL EDL!  It was flawless and exceeded everyone's expectations – great job!

Following the landing, the MSL mission manager came over to personally thank us and asked that we extend his most sincere and deep appreciation for the outstanding support of the DSN and ESA teams.  It is always an honor to be collaborating with our international partners and to be working together with such a dedicated and highly skilled team.  We have changed the world today, together.  And we have demonstrated once again the tremendous benefits of international collaboration!

Sending ENORMOUS THANKS to our ESA partners!

Best regards,

Susan C. Kurtik
Jet Propulsion Laboratory
Deep Space Network
MSL Mission Interface Manager

What is Open Loop Recording?

How Mars Express will listen to Curiosity

3-D waterfall diagram showing the open loop recording made by Mars Express of MER-B (Opportunity) during the rehearsal overflight for Curiosity EDL.

You'll see a lot on our coverage of the Curiosity landing about Open Loop Recording,' something which was hinted at in a previous post about the difference between 'signal' and 'data'.

OLR refers to the type of recording that will be made by Mars Express as Curiosity descends towards Mars, and in parallel by ESA's New Norcia station here on Earth.

In open loop recording, we don't try to decode the bits and bytes being sent by the descending lander but instead try and listen to as much of the radio spectrum as we can, hopefully detecting the tone of the lander's transmissions within this spectrum. Think of it like listening to a crowd of people – you can either focus on the words one person is saying, or listen to the whole crowd to get a full picture of what's going on; that's what we'll do with open loop recording.

On Mars Express we'll use our UHF Melacom radio to listen in on the UHF part of the spectrum – usually used on Earth for radio and television transmissions; it's also used at Mars as the frequency that different orbiters and landers use to talk to each other.

From New Norcia we'll be listening to the X-Band part of the spectrum – used on Earth mainly for radar systems but also as a way of communicating with spacecraft across the solar system (Mars Express uses X-Band for its main link back to Earth).

Each of these parts of the spectrum is actually a wide range of frequencies and in open loop we listen to as many as possible, creating a diagram like the one in the picture above.

Continue reading

ESA, NASA, Parkes: Big ears on Earth will listen to MSL descend

Editor's note: We're delighted to post this update on the international, behind-the-scenes cooperation to implement the MSL 'ground listening' campaign. It highlights the hard work, months of preparation and terrific cooperation between ESA, NASA and international partners on a technical, operational and interpersonal level. Thanks to NASA's Susan Kurtik and ESA's Wolfgang Hell for kindly providing information for this report.

On 6 August, ground stations and a radio telescope operated by multiple nations will be listening to signals from NASA's MSL mission as it descends through the Martian atmosphere to deliver the Curiosity rover safely onto the Red Planet's surface.

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 stations involved are all in the Land Down Under, since that's the bit of Earth that will be facing Mars at around 01:00 CEST next Monday morning, as MSL approaches its nail-biting plunge into the Mars atmosphere to touch down in Gale Crater.

During this crucial phase of the mission, MSL will transmit two radio links – one direct to Earth in X-band, which is also being used  for routine telecommanding during the cruise to Mars, and a ‘proximity link’ in the UHF band for direct communication with spacecraft orbiting Mars.

To get a good idea of the importance of the ground campaign, let's first look at the in-flight tracking efforts for the proximity link.

International fleet tracks MSL from Mars orbit

"The primary monitoring of MSL's Entry, Descent and Landing – EDL – phase will be provided by two NASA spacecraft in orbit around Mars: Mars Reconnaissance Orbiter [MRO] and Mars Odyssey. These two 'platforms' will be backed up by ESA's Mars Express [MEX]," says Michel Denis, MEX Spacecraft Operations Manager and responsible for MEX tracking support to MSL at ESOC.

(See our earlier post, 'Mars Express to track 7 minutes of terror' for details – Ed.)

Odyssey is the only one of the three that can provide the so-called 'bent-pipe' (or real-time) relaying of signals and is expected to give the first indication to NASA that Curiosity has arrived; confirmation of safe landing is expected by NASA at around 07:31 CEST.

Odyssey over Mars' South Pole: NASA's Mars Odyssey spacecraft passes above Mars' south pole in this artist's concept illustration. The spacecraft has been orbiting Mars since October 24, 2001. Credit: NASA

Odyssey over Mars' South Pole: NASA's Mars Odyssey spacecraft passes above Mars' south pole in this artist's concept illustration. The spacecraft has been orbiting Mars since October 24, 2001. Credit: NASA

In contrast, MRO and MEX can only track, store and then forward recorded signals later.

Artist's concept of the Mars Reconnaissance Orbiter. Image credit: NASA/JPL

Artist's concept of the Mars Reconnaissance Orbiter. Image credit: NASA/JPL

"Only Odyssey can receive, decode and then relay to Earth the actual telemetry data coded into the those signals. Conversely, MRO and MEX will save on board 'open-loop' recordings," says Denis.

This means they will record only the spectra of the radio signals and the related Doppler variations in signal intensity, and not the encoded telemetry.

(NASA's Susan Kurtik, MSL Mission Interface Manager at JPL, adds: In fact, we will be able to extract telemetry from the MRO open-loop recording, although it will take ~8 hours to process - Ed.)

(The variations in signal strength due to the Doppler effect are explained by the rather famous ambulance siren analogy.)

Ground tracking campaign provides crucial support

Now, let's look at the ground tracking campaign, the crucial, 'behind-the-scenes' activity in support of Curiosity's arrival at Mars provided by stations on Earth.

Continue reading

New Norcia to track Mars Science Laboratory

On 6 August, ESA's 35m deep space station at New Norcia, Australia, will track the arrival of NASA's Mars Science Laboratory at the Red Planet.

On 31 July, in a test, New Norcia successfully acquired telemetry from MSL at 13:30 CEST; all data was passed to NASA JPL. Two additional test tracking sessions are booked for 2 and 3 August.(We'll post an update on NNO's involvement in MSL arrival later in the week.)

ESA's 35m station at New Norcia, Australia, will track NASA's MSL arrival at Mars. Credit: ESA

ESA's 35m station at New Norcia, Australia, will track NASA's MSL arrival at Mars. Credit: ESA

More details on NNO via ESA web.

And, if you haven't seen this yet, surf on over to NASA's JPL website to access a very cool visualisation tool that demos the entire EDL (entry, descent and landing) phase - note: Java required.