Update 27 May

Today’s update from the MEX team at ESOC on progress of the VMC Schools Campaign, via Spacecraft Operations Engineer Simon Wood. More VMC images are expected to arrive today and tomorrow.

DSA 3 Malargüe

This image, taken in 2012, shows DSA 3 Malargüe station, one the world’s most sophisticated tracking stations used for deep space communications, as it neared inauguration in Malargüe, Argentina. Credit: ESA – CC BY-SA IGO 3.0

We had small glitch in the connection to the Malargüe DSA 3 ground station (DSA 3) during yesterday’s data downlink. This happens from time to time, however it is not a problem for us, as Estrack ground stations store all the data received at the station for at least 8 days.

This meant that we were able to recall the missing few minutes of yesterday’s communication pass from the ground station and feed it into the mission control system here at ESOC this morning, so no data were lost.

The last image received in yesterday’s downlink was a nice image of Phillips crater!

Acquisition of signal from Curiosity!

MEX Spacecraft Operations Engineer Simon Wood points to telemetry packets streaming down from Mars Express, indicating that signals were received earlier this afternoon from NASA’s Curiosity on the surface. Test of the contingency relay link using Mars Express is complete!

Testing cooperation: ESA’s Mars Express transmits commands to NASA rover

This update sent in earlier today by ESA’s Simon Wood, one of the engineers working on the Mars Express mission operations team at ESOC.

Today, ESA’s Mars Express orbiter will send telecommands to NASA’s Curiosity rover on the surface of Mars.

This self-portrait of NASA's Curiosity Mars rover shows the vehicle at the "Mojave" site, where its drill collected the mission's second taste of Mount Sharp. Credit: NASA/JPL-Caltech/MSSS

This self-portrait of NASA’s Curiosity Mars rover shows the vehicle at the “Mojave” site, where its drill collected the mission’s second taste of Mount Sharp. The scene combines dozens of images taken during January 2015 by the Mars Hand Lens Imager (MAHLI) camera at the end of the rover’s robotic arm. The pale “Pahrump Hills” outcrop surrounds the rover, and the upper portion of Mount Sharp is visible on the horizon. Darker ground at upper right and lower left holds ripples of wind-blown sand and dust. Full image and caption via NASA web. Credit: NASA/JPL-Caltech/MSSS

The transmission is part of a routine quarterly test of the communications link between MEX and Curiosity – NASA’s Mars Science Laboratory (MSL). Aside from its prime science mission, Mars Express is able to provide contingency communications with MSL (or with any NASA rovers) in case of any problems with the normal data relay links.

This particular test consists of MEX hailing MSL – sending a specific signal requesting MSL to listen – then transmitting commands (provided by the MSL team at NASA/JPL) to the rover and then recording data transmitted back.

Background sequence of activities

  • MEX mission planning system schedules pointing of MEX’s UHF (ultra high-frequency) antenna at MSL – end-December 2104
  • MSL team provides command file (i.e. the telecommands to be transmitted) to the MEX flight control team at ESOC – last week of February 2015
  • MEX flight control team uploads the commanding ‘products’ (files to be executed on board MEX) on 27 February; these were generated on 24 February
Mars Express orbiting the Red Planet - artist's impression Credit: ESA/Alex Lutkus

Mars Express orbiting the Red Planet – artist’s impression Credit: ESA/Alex Lutkus

Operations timeline today

All times UTC

14:29 MEX will slew from Earth pointing to pointing its UHF antenna at MSL on the surface
14:41 MEX UHF antenna switches on – takes 15 mins to warm up
14:56 Overflight begins with MEX hailing MSL; overflight lasts 9 mins
15:05 MEX begins to slew back toward Earth pointing

Data received from MSL will be transmitted back to Earth by MEX at around 16:30 UTC via ESA’s deep-space ESTRACK station in Malargüe, Argentina.

Later, NASA’s deep-space network teams will extract the data from the MEX packet archive and pass this on the the MSL team for analysis.

Best regards from the MEX control team at ESOC!

– Simon

Commands on board – GO for flyby

The commands that will automatically pace Mars Express through its pointings and science observations on Sunday are now confirmed on board, so we are ‘GO’ for Siding Spring flyby.

Mars Express ready for comet Siding Spring

On 14 October at 16:18 CEST, Comet Siding Spring will be 25,001,331 km from the centre of Mars, 24,997,942 km from the surface of Mars (mean) and 24,997,399 km from Mars Express, closing at a speed of -55.88 km/second.

Comet C/2013 A1 Siding Spring seen on 6 September 2014 from Argentina. Image credit: César Nicolás Fornari https://www.facebook.com/cesar.fornari

Comet C/2013 A1 Siding Spring seen on 6 September 2014 from Argentina. Image credit: César Nicolás Fornari https://www.facebook.com/cesar.fornari

For the Comet Siding Spring encounter this weekend, the Mars Express mission team have decided to not execute the initial contingency plan of pointing the high gain antenna toward the expected direction of comet particles and switching off all non-essential systems. Instead, we will be taking advantage of this remarkable opportunity to perform science observations of the comet – yet with a few precautions.

Siding Spring will pass by Mars at 139 500 km – a little more than
1/3 the distance between Earth and our Moon.

The final decision was made at the beginning of October. As we had two plans ready – one dubbed ‘nominal science’ and one ‘contingency’ – we were able to make this decision close to the encounter date and take advantage of the latest estimates of comet activity.

In creating the weekly observation plan for the spacecraft, several teams and many different factors are involved. Not only do we have to decide on where to point the spacecraft but we also have to take into account the amount of data generated, ground station availability, power requirements, thermal conditions, pointing restrictions and several others. Each of these is a lot of work in itself and trying to have two plans that were as similar as possible kept our mission planning team quite busy. This is why we have to plan everything far in advance.

So, the plan we will use is much like our standard weekly operations, but with a few additional precautions:

  • NASA’s DSN deep space tracking network are providing excellent support and will be allocating all of their antennas at both their Madrid and Goldstone sites purely to support the ESA, NASA and ISRO Mars missions. As well as using two of their 34m antennas to perform dumps of science data, we will be using the two giant 70m antennas to track a beacon signal that will be transmitted from one of the Mars Express low gain antennas (this was originally part of our contingency plan, but will be used in this now-routine science plan to give us an indication that all is well on the spacecraft).
  • We will also perform additional checks to the spacecraft systems. Once we get our first data after the comet encounter, engineers will go through all subsystems to be sure that everything is nominal and compare system status values to default values recorded earlier.
  • The Data Management Systems Engineers will dump all the data from our computer systems on Monday to be sure that nothing has become corrupted and our Power/Thermal Engineers will perform a test the week after flyby to measure any change in the performance of our solar arrays.

We are not expecting to find any problems but rather perform these tests so as to be sure.

MEX science during Siding Spring

Presentation by H. Svedhem, ESA’s mission scientist for MEX, detailing the plans for science during Siding Spring flyby this week and next.

This presentation was given at the Comet Siding Spring (C/2013 A1) Science Workshop, NASA JPL, 19 September 2014.

The recording of the workshop features Hakan here:

From 1:17:00 to end

and

Until 18:29

Waking up with a little help from our friends – Part 2

Not only is NASA helping Rosetta exit hibernation: ESA’s very own Mars Express has been standing in for Rosetta in a series of crucial tests to ensure the NASA ground stations are ready to track the comet chaser. Andy Johnstone, from the Mars Express team here at ESOC, sent in this report.

Although all the attention for Rosetta wake up is mainly on the spacecraft itself, the other half of the equation is the ground stations that will be used to listen for the signal, NASA’s DSS-14 in Canberra and DSS-63 in Goldstone.

If, by chance, no signal were to be detected on 20 January, this could mean that either (a) Rosetta has a problem, or that (b) possibly there is something wrong at the ground station.

Mars Express Credit: ESA/Alex Lutkus

Mars Express Credit: ESA/Alex Lutkus

Therefore, to reduce the possibility that there are any problems on ground, and since the radio systems on our two spacecraft are very similar, a test campaign was carried out using Mars Express; MEX ‘pretended’ to be Rosetta transmitting to the ground stations to ensure they are in perfect working condition.

The testing involved us, the MEX team, setting Mars Express to use its S-band transponders (which are normally only used for radio science or for emergency communications) to transmit at a very low bit rate, as Rosetta will on Monday.

This involved a lot of behind-the-scenes work from both ESA’s Mars Express team and our colleagues at NASA DSN (including having them come in to work on weekends and on US Thanksgiving). But it paid off: a series of five test passes demonstrated to us that the 70m antennas and the teams manning them do a great job and are ready for Rosetta’s wake up.

Best of luck to the Rosetta team and we’re looking forward to the event on Monday!