FIRST TEST SUCCESS FOR LARGEST MARS MISSION PARACHUTE
The largest parachute ever to fly on a Mars mission has been deployed in the first of a series of tests to prepare for the upcoming ExoMars mission that will deliver a rover and a surface science platform to the Red Planet.
The spacecraft that will carry them is due for launch in July 2020, with arrival at Mars in March 2021. The rover will be the first of its kind to drill below the surface and determine if evidence of life is buried underground, protected from the destructive radiation that impinges the surface today.
A carrier module will transport the rover and the science platform to Mars within a single aeroshell. A descent module will separate from the carrier shortly before reaching the atmosphere, whereupon a heatshield, parachutes, thrusters and damping systems will reduce the speed, delivering them safely to the surface.
The focus of the latest test, conducted in sub-zero conditions in Kiruna, Sweden earlier this month, was the 35 m-diameter second main parachute. The test demonstrated the deployment and inflation of the parachute with its 112 lines connected to a drop test vehicle, via the deployment of a smaller 4.8 m-wide pilot chute.
The complete parachute system, totaling some 195 kg, is stowed in a dedicated canister. The second main parachute of 70 kg is folded with its 5 km of cords in a precise way – a process that takes around three working days – to ensure it is extracted properly.
The assembly was lofted 1.2 km above the ground with a helicopter, and the sequence initiated after the vehicle was released. About 12 seconds after the pilot chute was inflated, the second parachute release was triggered.
GoPro cameras on the 500 kg test vehicle looked up at the parachute inflation, and onboard equipment sent telemetry in real time as it descended in about two and a half minutes to the ground.
“The successful deployment of our large ExoMars parachute using a smaller pilot chute and its subsequent stable descent without damage, is a major milestone for the project,” says ESA’s Thierry Blancquaert.
“It was a very exciting moment to see this giant parachute unfurl and deliver the test module to the snowy surface in Kiruna, and we’re looking forward to assessing the full parachute descent sequence in the upcoming high-altitude tests.”
That testing will see the equipment dropped from a stratospheric balloon from nearly 30 km, to more accurately represent the low atmospheric pressure on Mars – a vital aspect when considering parachute inflation.
The subsequent tests will also investigate the full parachute deployment sequence, which comprises two main parachutes, each with a pilot chute.
The dual parachute approach accommodates the much heavier descent module of the ExoMars 2020 mission – some 2000 kg compared with nearly 600 kg of the previous mission.
Rover test: What's it like to ride a rocket to Mars?
So, if you spend a billion euros on a space mission, you better be sure it can survive the rocket ride off Earth.
This video shows a model of Europe's upcoming Mars rover being shaken to simulate the violent first few minutes of flight on leaving the launch pad.
ExoMars, as it is known, is a joint project with Russia to put a mobile laboratory on the surface of the Red Planet in 2021.
The hi-tech rover will look for signs of past or present life.
The vehicle pictured being put through a shake test at Airbus in Toulouse, France, is what is called a Structural Thermal Model, or STM.
It is a near-exact copy of the rover that will eventually be sent to Mars.
Engineers use this STM to run the rule over their design.
If there are flaws and something breaks on this test model, the engineers have time to make revisions for the "flight model".
The rover will be despatched on a Russian Proton vehicle
Peak frequencies in these shake tests reach 100Hz (100 cycles a second). G-forces (accelerations relative to standard Earth gravity) of 10.5 are achieved.
As well as being shaken, the STM has to spend time in a special chamber to see that it can cope with the sort of temperature extremes experienced during a Mars mission. It will have to show it can also perform in a vacuum.
The flight rover will follow behind the STM and repeat all the same checks.
The ExoMars mission is due to launch to the Red Planet on a Proton rocket in 2020.
European Space Agency member states, Russia and America have contributed instrumentation.
A key experiment will be to drill up to 2m below the surface of Mars.
It is thought that if any microbes exist on Earth's neighbour, they will be below ground. To date, surface missions have never got more than a few centimetres into the covering rock and dust.
The European industrial team working on ExoMars is led from Thales Alenia Space in Turin, Italy.
The flight model for ExoMars is currently being assembled at Airbus's British factory in Stevenage.
Artwork: The ExoMars rover will launch in 2020 and land in 2021
Wanted: Inspiring name for Europe's 2020 Mars rover
Here's your chance to name the European rover that will go to Mars in 2020.
Currently called ExoMars, the six-wheeled robot needs something a bit more engaging and inspiring for when it lands on the Red Planet.
Astronaut Tim Peake is leading the hunt for a great moniker.
He wants everyone to go to a special website set up for the purpose and enter a suggestion. But don't think "Spacey McSpaceFace" is a goer because this is not an online poll.
All ideas will be put before an expert panel and it is they who will make the final choice.
The vehicle is currently being assembled at the Airbus factory in Stevenage.
Its job when it lands on Mars in 2021 will be to seek out signs of present or past microbial life. The robot will even have a drill to dig 2m into the ground to see if any bugs are hiding away from the surface.
Tim says thinking about the rover's mission might be the source for a great name. "I often get asked, 'is there life out there beyond Earth?'. It's a very fundamental question, and it's one that this rover is going to try to answer," he told BBC News.
Dr David Parker, the director of human spaceflight and robotics at the European Space Agency, agreed: "The Americans called their Mars rovers Spirit, Opportunity and Curiosity. We've tended in the past to name our missions after famous scientists.
"But, yes, perhaps this time we go with a name connected with the search for life - biology, genetics, DNA, whatever. Who knows? We just want a great name."
Britain acquired the naming rights for the rover at Esa's Ministerial Council in 2014. It got them because the country is the key financial contributor to the rover; part of Europe's two-part ExoMars project. The other part is a satellite that is already orbiting the planet studying its atmosphere.
However, the UK Space Agency says it wants the search for a name to be as wide as possible. This means anyone resident in an Esa member state can put forward a suggestion (including associates, eg Canada).
Tim Peake launched the name search at the Farnborough International Air Show on Friday. He used the same event to kick off the Holiday Makers campaign - an initiative aimed at getting children making, inventing and exploring engineering.
The campaign is running a series of free family-friendly activities and events across the country as part of the government's Year of Engineering.
The Esa man was helped by Dr Suzie Imber, from the University of Leicester's Department of Physics and Astronomy. Suzie won the BBC show Astronauts: Do You Have What It Takes?"
She said: "It's always a delight to open young people's eyes to how exciting engineering and science can be and the government's Year of Engineering campaign is a fantastic way that scientists like Tim and me can share some of the amazing research that is happening in labs across the country, and the vital role engineers play in this."
ExoMars: Where to send Europe's robot rover?
Scientists and engineers are to meet in Leicester to choose a landing site on Mars for Europe's 2020 rover.
The six-wheeled robot will be targeted at one of two near-equatorial terrains on the Red Planet.
The ExoMars Site Selection Working Group must weigh which of the pair represents the biggest scientific interest but also offers a fair chance of getting down safely.
Landing on the planet is notoriously hard. Most efforts have failed.
Assuming ExoMars can overcome this hurdle, it will use a package of instruments to look for signs of past or present life, employing a drill to extend the search below the harsh conditions that persist at the planet's surface.
The meeting at Leicester's university has been convened by the European Space Agency (Esa) and comprises senior academics and officials from industry. Russia, a joint partner on the mission, is also well represented.
What is the choice?
Scientifically speaking, these locations are quite similar. They are ancient landscapes that contain abundant clays - the type of sediments which result from the alteration of rock through prolonged contact with water.
It is in just this kind of setting where you might find evidence for ancient microbial life.
Curiosity, the American rover currently operating on Mars in a deep bowl known as Gale Crater, has detected clay minerals in mudstones that very probably formed in lakes and the streams that fed them.
The sediments of interest at Oxia Planum and Mawrth Vallis likely had similar sorts of origins.
Is science the only consideration?
Far from it. Great scientific prospects count for nothing if you cannot land the robot in one piece.
Europe's previous touch-down effort, the Schiaparelli mission, crashed into Mars' surface in 2016 when the probe's onboard computer became confused about its altitude during the descent and switched off the braking thrusters far too early.
Schiaparelli smacked into the ground at over 300km/h.
ExoMars will be using a similar entry, descent and landing strategy that incorporates a capsule, a parachute system and retro-rockets.
A factor that will bear heavily on the Leicester discussions is the knowledge that Oxia is at a much lower elevation than Mawrth - by about 1,000m. This would give the descending robot's parachute much longer to bite Mars' thin atmosphere and slow the supersonic approach towards the surface.
What else has to be thought about?
In addition, Mawrth's position is slightly to the north of Oxia.
The angle of approach required to get to this higher latitude necessarily produces greater uncertainty in the eventual touch-down point.
Engineers talk of confidence zones that are elliptical in shape. For both locations these ellipses are 19km wide, but, in the case of Mawrth, the length is 190km. For Oxia, it's 104km.
High-resolution satellite images have been acquired of both sites.
These will have been examined for hazards such as steep slopes and deep gullies, and also for the preponderance of large boulders. ExoMars will come down on its Russian-built lander. If the legs find very uneven ground, the rover might not be able to drive off the platform, or, worse still, be tipped over.
How is the rover's development progressing?
This is a mission that has experienced delay after delay.
Originally set for 2011, the launch from Earth slipped to 2013, to 2016, to 2018, and is now scheduled for mid-2020.
This means all the various components of the mission - the rover, its landing mechanism and the cruise vehicle that shepherds everything from Earth to Mars - really need to be at Russia's Baikonur launch site in about a year's time to begin final integration and testing.
Officials say the schedule, despite some hiccups, is on track.
Clear signs that we are getting close include the inauguration of the rover's mission control in Turin later this month.
One very good piece of news to report is the restoration of autonomous navigation to the robot. This software will enable ExoMars to find its own way across the ground without the constant intervention of engineers back on Earth, and should speed up dramatically its ability to survey scientifically interesting places to drill.
When do we get a decision?
America is also sending a rover to Mars in 2020. This is, broadly speaking, a copy of the Curiosity rover, although it will have different instrumentation and seek to find rock samples it cache for later return to Earth laboratories.
As with ExoMars, this mission is going through a site selection process. This should produce a recommendation sometime before the end of the year.
The Leicester working group's deliberations are closed to the media, but an announcement on its preference is promised for Friday afternoon.
Protocol requires this be signed off by the heads of Esa and the Russian space agency (Roscosmos) before it becomes ExoMars' official destination, but it is highly unlikely that the Leicester choice would be blocked.