Replay of today's excellent webcast from ESOC, where top ESA folks profiled and highlighted Mars Express past, present and future. Well worth watching in its entirety; media Q&A at the end are also quite good.
The data are finally here!
You'll recall our blog posting early in October (see Mars Express to relay first science data from Mars Curiosity) when we got word that Mars Express would, for the first time, relay actual science data from NASA's Curiosity. Now, after a bit of a wait, we've got the the images transferred by Mars Express plus some nice context images showing the rocky target, thanks to Roger Wiens, PI on ChemCam, and several of the colleagues at NASA.
There's a full report in ESA web today (see Fostering Curiosity: Mars Express relays rocky images to NASA), which is well worth a quick read.
To summarise, MEX relayed a set of two close-up images of target 'Rocknest3' acquired by the the Remote Micro-Imager (RMI) on the ChemCam on 4 October 2012 (Sol 57). ChemCam is more than only a 'cam(era)'; it actually comprises two units – the RMI plus the Laser-Induced Breakdown Spectrometer (LIBS). (See the ChemCam instrument page here). LIBS works by firing a laser at targets and analysing the chemical composition of the vaporised material. Is that cool, or what?
Our web report (and this blog post!) includes the two close-up RMI images plus two more: an RMI mosaic (combination of several images) showing the LIBS targets on Rocknest3, as well as a wider angle view of Rocknest3, acquired separately by Curiosity's MastCam.
Without further ado – voilà! The images relayed by MEX:
These two images were taken on sol 57 (4 October 2012) of target Rocknest3 using the ChemCam Remote Micro-Imager (RMI) on the NASA Curiosity rover at a distance of 3.7 m. The images were downlinked to Earth using ESA’s Mars Express orbiting spacecraft. The first image above was taken before a series of five ChemCam Laser-Induced Breakdown Spectrometer (LIBS) observations and the second image was taken after. The first image is centred on the fifth LIBS observation point. Rocknest is the name of the area where Curiosity stopped for a month to perform its first mobile laboratory analyses on soil scooped from a small sand dune. Rocknest3 was a convenient nearby target of which ChemCam made more than 30 observations overall consisting of 1500 laser shots; it was also interrogated by the arm-mounted Alpha Particle X-ray Spectrometer (APXS) instrument. Credits: NASA/JPL–Caltech/LANL/CNES/IRAP
The two processed RMI images were sent to us here at ESOC by Roger Wiens, ChemCam PI (principal investigator) at the Los Alamos National Laboratory, New Mexico, USA. Thanks, Roger, for the images and caption above!
The RMI mosaic image – showing the LIBs targets on Rocknest3 – was produced by Stéphane Le Mouélic, a research engineer at France's Université de Nantes and one of the collaborators on ChemCam (access the team bios here).
Stéphane is also co-investigator on the Visible and Infrared Mineralogical Mapping Spectrometer (OMEGA) on Mars Express.
The MastCam image was processed courtesy of Mike Malin of Malin Space Science Systems (as far as we've heard at ESOC, all these images will also go into the NASA/JPL website).
In a mail sent in earlier, Stéphane wrote:
I can just tell you that several of us in the ChemCam team are also involved in the Mars Express mission, and, as such, this successful communication of data between the two spacecraft also takes a sentimental value. Mars Express has provided a wealth of information and has paved the way for a new generation of explorers such as Curiosity. Making the two spacecraft work together is not only scientifically and technologically interesting, but also representative of how the collaboration of agencies is advancing science.
The Deputy PI for ChemCam is also French; Sylvestre Maurice is based in Toulouse, at France's Institut de recherche en Astrophysique et Planétologie (IRAP). Along with PI Roger Wiens, he was responsible for the design, construction, testing and delivery of the LIBS instrument on ChemCam ("ChemCam is the greatest of all instruments, the 'Jedi light-saber' of the MSL mission!").
To me, the cooperation between ESA and NASA extends even further: the RMI camera is a spare of a series of cameras on ESA's Rosetta mission, scheduled to arrive at the comet 67P/Churyumov-Gerasimenko in 2014. ESA-NASA and MSL-Rosetta – a spirit of collaboration!
Finally, we also heard from Brigitte Gondet, who is also a collaborator on both ChemCam and Mars Express at Institut d'Astrophysique Spatiale (IAS):
The quality of the images provided by the RMI camera (the head was developed at France's IAS and optics developed at IRAP) is outstanding. The context information for the LIBS analyses has proved essential for the scientific interpretation of the data. This combination of imaging and analysis has demonstrated its potential for future missions.
ESA–NASA cooperation at Mars is a continuing success, and, in this case, there is also tremendous involvement of the co-PIs and collaborators on the ChemCam science team from France!
IRAP - The Research Institute in Astrophysics and Planetology - opened in 2011. IRAP is a new mixed research unit of the CNRS (National Centre for Scientific Research) and University Paul Sabatier, Toulouse.
On 19 August, Sunday evening (European time), Mars Express will start its first data relay with NASA's Mars Curiosity rover in style by fitting in not just our first pass with Curiosity but also by 'rolling away' afterwards to talk with NASA's veteran Mars rover, Opportunity.
This will be the first time in the history of the Mars Express mission where this double lander contact has been attempted within a single orbit of the spacecraft (1 orbit around Mars for Mars Express lasts around 7 hours).
As the spacecraft approaches the planet it will turn away from Earth and 'roll' over the top of Curiosity's new home in Gale Crater, keeping the Melacom antennas pointed directly at the new rover.
After this contact, Mars Express will turn back to Earth briefly and then spin away again, performing the same 'Spot Pointing' manoeuvre for Opportunity as Mars Express flies over its location in Endeavour Crater. This double relay will be an exciting test of the capabilities of Mars Express, both in relay terms and in pointing, and to not only prove our communication capability with the new (and fantastic!) Curiosity rover but also to continue our commitment to its predecessor – the venerable Opportunity rover.
The past weeks have seen intense cooperation between NASA and ESA to coordinate and plan these activities, which are intended as demonstrations of the relay capabilities of Mars Express. The overflight of Opportunity will be part of a long-standing activity to periodically check the ability of Mars Express to relay data from Opportunity, if ever needed.
Many of these overflights were done leading up to the landing of Curiosity to cement the technical ability of the two agencies to work together on planning routine relay operations. The overflight of Curiosity will be the first time that Mars Express and Curiosity have actually 'talked' to each other.
During the landing of Curiosity, Mars Express only listened in and recording the radio signal of Curiosity, but Sunday evening, 19 August, the two spacecraft will actually have a 'conversation' and for the first time Mars Express will receive and decode actual data from the lander.
We're confident in the ability of the two spacecraft to be able to communicate for several reasons – the main one being that both implement an international standard called Proximity-1 [this is mentioned in our earlier Melacom post - Ed].
This standard was designed to make sure that even though the spacecraft come from different manufacturers and different agencies, the way they talk to each other is still the same – it can be thought of like an 'agreed common language'.
On top of this, is our extensive experience relaying data for Phoenix, Spirit and Opportunity and the fact that a team from QinetiQ (who built our Melacom radio) travelled to JPL to test a copy of it with a copy of the Curiosity radio. However, any new activity in space is challenging and we stand ready at ESOC to investigate, analyse and improve – optimising our ability to support the Curiosity mission for NASA.
All of this will allow Mars Express to make a call to Curiosity in Gale Crater and between the spacecraft agree autonomously to exchange data. Curiosity will send back data that will be decoded by Mars Express and stored ready for forwarding to Earth; then we'll quickly reset and prepare a very similar activity for Opportunity in Endeavour Crater.
Next, on Monday morning, Mars Express will send the data to ESA's 35m New Norcia (Australia) ground station and then from there it will make its way to ESOC and on to the control room at JPL.
The data's journey will be long (Gale Crater/Endeavour Crater -> Mars Express -> New Norcia, Australia -> ESOC, Germany -> JPL, USA) but we'll make sure it arrives safe and sound – proving the ability of Mars Express to support communications with both Curiosity and Opportunity whenever needed.
We'll post more details when we know the results of the test and can hopefully announce on Monday that Mars Express has been 'qualified' as a really-long-distance relay for Curiosity – expanding the network of spacecraft and cooperation at Mars in spectacular style!
There's a nice photo gallery now in Flickr snapped during the media event at ESOC on Monday morning, showing some of the intense activity around the time of Curiosity's landing. There are also some nice photos of the Mars Express flight control team, including Spacecraft Operations Manager Michel Denis and MEX engineers Thomas Ormston and James Godfrey.
Mars Express engineer Thomas Ormston on console in ESOC's Main Control Room. Credit: ESA/D. Danesy
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.)
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!
Susan C. Kurtik
Jet Propulsion Laboratory
Deep Space Network
MSL Mission Interface Manager
MP3 audio recording of NASA's Curiosity arrival at Mars
While no human ‘heard’ NASA's Curiosity arrive at Mars this morning, the radio signals transmitted during descent and recorded by Mars Express have been processed and shifted into human-audible frequencies.
This provides a faithful reproduction of the ‘sound’ of the NASA mission’s arrival at Mars and its seven-minute plunge to the Red Planet’s surface.
Note: recording compresses full descent recording (~20 mins) into just 19 seconds.
Note for those interested: The 1D & 2D plots are available after the jump...
Click to download mp3 audio (or listen via SoundCloud) recording of Mars Express operations engineer Thomas Ormston conducting this morning's voice loop check with NASA JPL:
Spacecraft event time vs. Earth receive time
One of the most difficult things about operating a spacecraft around Mars (not to mention the different time zones), compared with the Earth, is that it's so far away!
Mars is so far away in fact that it takes radio signals quite a long time to get from the spacecraft back to Earth. During Curiosity EDL, this delay will be 13 minutes, 48 seconds, about mid-way between the minimum delay of around 4 minutes and the maximum of around 24 minutes.
This makes it a challenge to operate Mars Express because it's hard to have a conversation with the spacecraft, or react if anything happens on board. If there is a problem and the spacecraft tells us, we won't know for 13 minutes, and then even if we react straight away it'll be another 13 minutes before our instructions get back to Mars – there's a lot that can happen in half an hour at Mars (for example a whole Curiosity landing)!
To keep Mars Express flying safely, we load all the commands for the mission in advance and built in lots of autonomy to let the spacecraft take care of itself – you could say that for the Curiosity landing we're running completely on autopilot!
The delay is nothing to do with the spacecraft or the hardware on the ground – it can't be improved by a faster computer or a more powerful radio. In fact it is obeying the fundamental speed limit of the universe – the speed of light.
At 1,079,000,000 km/hour, light is pretty quick; you could get from here to the Moon in a little over a second! But that just underlines how far away Mars is.
All light (or electromagnetic radiation, which includes radio signals) travels up to this speed, and radio waves from Earth to Mars Express and back are no exception. Take a look at the Wikipedia article on the speed of light and you'll see how, in 1905, Einstein came upon the concept of this cosmic speed limit.
Above all, for tomorrow's coverage of the Curiosity landing it makes it challenging for us to work out when to tell you what's happening (as you've seen in our three column timeline)!
At ESOC, we talk about two different times – Spacecraft Event Time (SCET) and Earth Received Time (ERT). The former is what's actually happening at Mars right now, although we won't hear about it until over 13 minutes later, a time we call ERT.
The delay between the two is usually called the One-Way Light Time (OWLT) and the time for a message to go to Mars and come back is the Two-Way Light Time (TWLT), or round-trip time.
During all our coverage we'll follow NASA's lead and generally communicate events here and on Twitter to you in ERT because that's when we'll actually know what's happened. If we do communicate something in SCET we'll let you know so you (and us too) don't get confused – it's all part of the fun of exploring the Solar System!
This video shows the view of Mars Express from the Earth before, during and after the Curiosity landing. It demonstrates perfectly why we need to use a method called 'store and forward' to get the recording of the descent back to Earth.
At the start and end of the video, you can see Mars Express' big 1.6-m High Gain Antenna (the grey circle on the front of the spacecraft) pointed right at us. We need that to be pointed at us to be able to talk to Mars Express from Earth.
Unfortunately, to support the landing of Curiosity, we need to point our Melacom antennas at the incoming lander, and they're fixed perpendicular to the High Gain antenna. That's why during the middle of the video you see the spacecraft turn the High Gain Antenna away from us - it's so it can get the best possible view of the incoming lander.
In order to relay the recording of the descent, we store the data in our on-board memory - a bit like saving a picture to the memory card on your digital camera.
We have 12 Gigabits of on-board memory, which might sound small compared to your home computer, but it's plenty of space for what we need. Once we turn back to Earth, we can tell the spacecraft to forward the recorded data back to Earth, just like plugging in your camera and downloading the results from the memory card. In fact, due to the criticality of the Curiosity recording, we'll transmit it to Earth three times to make sure it reaches us safely.
So when you're watching the landing tomorrow, note that's why it'll take us a bit of time to swing the spacecraft around and dump the recorded data to ground. The JPL orbiter Mars Reconnaissance Orbiter will do the same thing and so will experience a similar delay.
In contrast, the live relay from Mars to Earth will be provided by JPL's venerable Mars Odyssey orbiter, the oldest spacecraft currently operating around Mars. It uses a different mode, called 'bent pipe', where it takes the incoming data and 'bends' it around and blasts it back towards Earth more or less simultaneously.
If all goes according to plan, this direct relay will be NASA's first confirmation of a successful landing, and the detailed recordings made in 'store and forward' by the other two orbiters will follow shortly after to provide us a full picture of this historic landing.