ExoMars nears launch, thanks to nonstop work in factory
Working around the clock to meet a 12-day launch window in March, European engineers are putting the final touches on a Mars orbiter that could shed light on whether tiny microbes or geologic activity still linger on the barren planet.
A stationary landing craft will accompany the orbiter on the seven-month journey to the red planet.
At launch, the tandem composite will weigh 4.3 metric tons, or 9,480 pounds, making the combined spacecraft one of the biggest and heaviest ever to go to Mars.
The duo will arrive at Mars on Oct. 19, 2016.
Inside a pristine chamber at Thales Alenia Space’s satellite factory in Cannes, France, technicians are finishing up preparations to ship the two spacecraft to their launch base at the Baikonur Cosmodrome in Kazakhstan.
The European Space Agency only authorized full development of the mission in 2013 — two-and-a-half years ago — and officials have so far kept to their commitment to have the two probes ready for launch in 2016.
“I cannot express how happy I am of being here, that we got to this point that some people thought was not going to come, at least not in time,” said Alvaro Gimenez, director of ESA’s science directorate. “But we are here. We are ready now to ship the spacecraft to Baikonur and launch it.”
The launch scheduled for March 14 aboard a Russian Proton rocket is the first of Europe’s two-part ExoMars program, ESA’s most ambitious Mars mission to date. Next year’s launch will be followed up in May 2018 by the liftoff of a European-built rover that will descend to the Martian surface.
The road to the launch pad appears for the 2016 launch appears smooth, assuming no last-minute glitches, according to Walter Cugno, ExoMars program director at Thales.
“We want to be ready for the first launch attempt, which is March 14,” Cugno told Spaceflight Now in an interview. “The launch window is up to the 25th of March, but we want to be ready for the first attempt to have some margin just in case.”
Cugno said ground crews have worked in three shifts — around the clock — more more than a year to make sure the two spacecraft are ready to meet their launch date.
The long days are not over.
A final vibration and acoustic test of the spacecraft, along with communications link checks with Europe’s spaceflight control center in Germany, are the last items on the to-do list before the orbiter and lander are packed up and flown to Kazakhstan.
In the video below, Cugno gives a brief tour of ExoMars Trace Gas Orbiter and attached Schiaparelli lander during a press visit Nov. 25.
Three Antonov cargo jets will depart an airport in Torino, Italy, on Dec. 18, 19 and 21. The flights will go through Moscow for a customs check, then proceed to Baikonur.
The first flight of the heavy-duty transport plane will deliver ground support equipment, including a tent in which the Mars lander will be prepared for launch. The tent is necessary to meet stringent contamination restrictions crafted to prevent Earth bacteria from reaching Mars, and no clean room exists at Baikonur pristine enough to meet the requirements, Cugno said.
The second and third Antonov transports will take the lander and orbiter to the Kazakh launch base on separate sorties.
Teams have just one day of schedule margin, excluding weekends, to have the entry module ready in time for March 14. The schedule for the orbiter is less tight, Cugno said.
Technicians will work nonstop over the holidays to try to build up more breathing room in the schedule. If the launch is not off by March 25, or perhaps a couple of days later, the mission will be delayed more than two years because the planets are out of alignment to make the voyage possible.
“We arrive in Baikonur a few days before Christmas, and we are going to work through Christmas continuously without any break until we will be finalizing the checkouts in preparation for the launch,” Cugno said.
Propellants for the lander’s descent rockets will be loaded at the end of January, and workers will attach the descent capsule to the orbiter Feb. 12, according to Cugno. Then the orbiter will be ready to receive its propellants, totaling 2.3 metric tons (5,070 pounds), comprising more than half its liftoff weight.
The procedure to attach the spacecraft to the Proton launcher and its Breeze M upper stage begins Feb. 26.
Cramped work timelines are nothing new for the ExoMars program, which still faces a schedule and budget crunch to have the rover and its carrier ready in time for its May 2018 launch window.
Delays and the sudden withdrawal of NASA’s partnership have shaped the ExoMars program, which started as part of ESA’s Aurora exploration initiative in 2001.
NASA announced in 2012 the U.S. government could not afford a plan to supply a “sky crane” descent system — a vehicle similar to the landing module that carried the Curiosity rover to the Martian surface — for the ExoMars rover mission. The U.S. space agency also said it would not provide an Atlas launcher the 2016 and 2018 missions, and it canceled a plan to build a U.S. rover to go with the European 2018 launch, which would have landed two rovers on Mars in one go.
In the wake of NASA’s departure from the program, ESA turned to Russia to launch the missions and develop the 2018 rover’s atmospheric entry system.
“The Russian space agency has taken an invitation made by ESA to participate in this project, and we can say, even to save it,” said Sergey Saveliev, deputy head of Roscosmos, in a presentation to reporters Nov. 25.
“Of course, ExoMars is a very complex and costly project, which can simply not be done by one country alone, so it is the result of our cooperation,” Saveliev said. “We at Roscosmos value a lot our partnership with our European colleagues, and we believe that this project will not be the last one, that other important and interesting projects will follow.”
The first launch of the ExoMars program was set for blastoff in January, but managers at Thales received an alert from a subcontractor that prompted a decision in September to reset the launch to a backup opportunity in March.
Engineers removed two pressure transducers from the lander’s propulsion system command chain to avoid a potential flaw that could have threatened the mission. Without the transducers, ground controllers give up some insight into the performance of the entry probe, but the propulsion system can still function normally, officials said.
ESA and Thales Alenia Space briefed reporters on the status of the ExoMars missions in Cannes on Nov. 25, showcasing the 2016 spacecraft in launch configuration, with the orbiter fully assembled crowned by the landing module.
The landing craft is named for Italian astronomer Giovanni Schiaparelli, who observed Mars in the 19th century through telescopes and created the first maps of the red planet.
Schiaparelli marked natural channels coursing across Mars, and his maps inspired a wave of interest in the red planet, leading to the construction of new telescopes to further study the rust-colored world.
The orbiting component of the 2016 mission, called the Trace Gas Orbiter, hosts science instruments from across Europe and Russia.
Two sensor packages will measure the constituents of the Martian atmosphere with greater spectral resolution than ever before, teasing out the tiniest concentrations of molecules.
A key objective of the Trace Gas Orbiter will be to look for methane, a gas that has been intermittently detected in the planet’s atmosphere by Europe’s Mars Express orbiter, ground-based observatories and NASA’s Curiosity rover.
But the methane levels are extremely low, bordering on signal noise in the data streams from Curiosity, with apparent occasional unexplained spikes.
Jorge Vago, ESA’s ExoMars project scientist, said the methane could come from two possible sources.
“One would be metabolizing active bacteria, maybe in the subsurface,” Vago told reporters Nov. 25. “The other one could be some processes that also happen on Earth in which certain minerals in the mantle react with water at relatively low temperatures, for geology, at 200 to 300 degrees (Celsius), releasing hydrogen which then could combine with carbon dioxide to form methane.”
While the prospect that the methane could come from burps from microbes is tantalizing, scientists say either explanation would be enlightening.
“We are very interested in being able to possibly confirm the presence of methane, but also being able to maybe explain what the origin is,” Vago said. “In any case, whether it’s the biological origin or the geological origin, if it is coming from the subsurface, in both cases it would mean the presence of liquid water, and it points to a Mars planet that is more ‘alive’ than what we thought before now.”
Jean-Pierre Bibring, a scientist at Paris Sud University and a member of ExoMars’ science team, said the possibility of a geologic source for the methane carries weight among many Mars researchers.
Mars is at a point Bibring called “geological death,” when the convective engine deep inside a planet goes quiet. Earth, which is larger than Mars and still able to support churning super-heated rock deep underground, will reach a similar fate in the distant future, but still well before the sun goes dark.
Volcanic activity on Mars ended less than 100 million years ago, perhaps as little as a few million years ago, Bibring said.
“But it might be the outgassing has not finished, and that most of what we see now in the atmosphere of Mars, the few millibars of what we have including the trace gases, are the result of the still active processes deep inside Mars,” said Bibring, who is also the chief scientist on Europe’s Philae comet lander.
“How does that happen? Mars will tell us that because Mars is at that point where volcanism has probably died, but not the outgassing, and that’s really the beauty of TGO (Trace Gas Orbiter),” Bibring said in Cannes. “It will monitor this phase while it’s still happening on Mars now, probably venting all sorts of things, such as methane. It’s not just the question of the biology, it’s much more than that.”
The orbiter also carries a camera to map the Martian surface, and a Russian-made neutron detector tailored to find deposits of water or minerals like clays, which formed in water on ancient Mars.
The Schiaparelli lander, developed with Italian leadership, would become the first European craft to safely touch down on Mars.
Its prime mission is purely as a technological demonstrator, aiming to validate Europe’s ability to land an object on the red planet.
Weighing 600 kilograms, or 1,322 pounds, the landing probe resembles a flying saucer covered in an ablative heat shield and golden insulation. Three days before the spacecraft arrives at Mars, on Oct. 16, the orbiter will release the descent probe for its plunge to the Martian surface.
It is heading for a flat plain named Meridiani Planum, targeting a landing point near the location of NASA’s Opportunity rover.
Schiaparelli’s six-minute descent on Oct. 19, aided by a supersonic parachute and braking rockets, will culminate with a crash landing of sorts. The thrusters will cut off when the probe’s landing radar detects it is less than 2 meters, or 6.6 feet, above the ground.
A “crushable” carbon-fiber structure, made in Spain, will protect the lander when it hits the surface.
Schiaparelli has its own suite of science instruments, primarily designed to monitor the Martian atmosphere during descent and to serve as a meteorological station on Mars during the battery-powered lander’s short life, which is expected to last between two and eight days.
The craft’s arrival in October will be during the Martian dust storm season, making Schiaparelli the first Mars lander to touch down under such conditions. Scientists hope to get a vertical profile of the atmosphere on the probe’s descent for the first time during the dust storm season.
Europe’s last mission to Mars in 2003 launched the Mars Express orbiter, which is still returning science from the red planet well beyond its two-year lifetime, and the Beagle 2 landing module built in Britain.
Ground controllers never heard from Beagle 2 after its landing attempt, but scientists early this year revealed new imagery from NASA’s sharp-eyed Mars Reconnaissance Orbiter apparently showing the spacecraft intact on the red planet, but with its solar arrays still partially folded.
The discovery led engineers to conclude Beagle 2 may have survived its landing, but a problem prevented full deployment of the solar panels, potentially blocking the antenna that was to radio its status to Earth.
Schiaparelli’s flight to Mars is Europe’s second try, with a much bigger package than Beagle 2. It goes to Mars with a doppler radar guidance system, modernized control algorithms and a computer that will be crucial to the 2018 mission’s rover landing.
It also boosts Europe’s bonafides when it comes to future Mars projects, such as an audacious concept to return samples to Earth.
“If you want to be a partner in the future in more missions to Mars, if you don’t demonstrate your capability to land, you are not at the right level,” Gimenez said. “We have to demonstrate we can do it ourselves, and that’s what we will do with this mission.”
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Source: Space Flight
30 Nov, 2015
ExoMars nears launch, thanks to nonstop work in factory
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