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Thread: ExoMars mission

  1. #91
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    Quote Originally Posted by Extravoice View Post
    Or perhaps something like the Ariane 5 counter rollover.

    http://www.math.umn.edu/~arnold/disasters/ariane.html?
    Well, not a rollover, but a saturation event this time.

    According to Spaceflight now:

    The IMU measured the rotation rate of the saucer-shaped lander during its descent, but engineers said the system became saturated — indicating maximum measurement — soon after Schiaparelli deployed its supersonic parachute and released the lower half of its heat shield as intended.
    The good news is that the event was recreated in simulations, so they should be bale to prevent it from ever happening again.
    I may have many faults, but being wrong ain't one of them. - Jimmy Hoffa

  2. #92
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    russianspaceweb.com on the ExoMars crash.

    http://www.russianspaceweb.com/exoma...ding.html#1123

    On November 23, 2016, ESA announced the preliminary results of the investigation into the Schiaparelli crash on the Martian surface on October 19.

    ESA said that good progress has been made in investigating the accident. According to the agency, the large volume of data recovered from the Mars lander shows that the atmospheric entry and associated braking occurred exactly as expected. The parachute deployed normally at an altitude of 12 kilometers and a speed of 1,730 kilometers per hour. The vehicle’s heat shield, having served its purpose, was released at an altitude of 7.8 kilometers.

    As Schiaparelli descended under its parachute, its radar Doppler altimeter functioned correctly and the measurements were included in the guidance, navigation and control system. However, saturation – maximum measurement – of the Inertial Measurement Unit, IMU, occurred shortly after the parachute deployment. The IMU measures the rotation rates of the vehicle. Its output was generally as predicted except for this event, which persisted for about one second – longer than would be expected, the agency said.

    ESA provided no explanation or any hypothesis at the time what could cause the "saturation" of the IMU.

    The ESA statement continued: when merged into the navigation system, the erroneous information generated an estimated altitude that was negative – that is, below ground level. This in turn successively triggered a premature release of the parachute and the back shell, a brief firing of the braking thrusters and finally activation of the on-ground systems as if Schiaparelli had already landed. In reality, the vehicle was still at an altitude of around 3.7 kilometers.

    This behavior has been clearly reproduced in computer simulations of the control system’s response to the erroneous information.

  3. #93
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    A rotational component translated into an altitude error? Seems like the guidance program needs tweaking.

  4. #94
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    Something named IMU must do more than measure rotation. Spaceflight 101: Schiaparelli Mars Lander (EDM)

    EDM hosts a pair of Inertial Measurement Units for redundancy. The LN-200 is a strap-down Inertial Measurement Unit using fiber-optic gyro technology with low accelerometer / gyro bias and random walks. LN-200 includes three solid-state fiber-optic gyros and three solid-state silicon Micro Electro-Mechanical System (MEMS) accelerometers to measure velocity and angle changes with high accuracy. Digital output from the IMU includes velocity and incremental angle provided to the GNC system via RS-485 serial bus.
    Northrup Grumman LN-200 IMU
    0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 ...
    Skepticism enables us to distinguish fancy from fact, to test our speculations. --Carl Sagan

  5. #95
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    ExoMars had two portions. One crashed but the more important part of the mission survived and is orbiting Mars. It has now sent back data and given us some pictures of Mars.

    http://gizmodo.com/here-are-our-firs...rop-1789462371

    n case Schiaparelli’s crash-landing left you thinking the European Space Agency’s ExoMars mission was a bust, rest assured it wasn’t. The mission’s scientific workhorse—its Trace Gas Orbiter (TGO)—is performing beautifully, as evidenced by the first images and splashes of data ESA has now received back from the Red Planet.

  6. #96
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    The second prat of the ExoMars mission to land a rover on Mars in 2020 was given the go ahead by ESA.

    https://www.newscientist.com/article...ier-this-year/

    Europe’s bold attempt to search for life on Mars will launch as planned in 2020, despite concerns over escalating costs and the spectacular loss of the mission’s lander demonstrator.

    European Space Agency (ESA) member states agreed to stump up the extra 440 million euro (£370 million) needed to ensure the future of the ExoMars Rover.

    The mission, the second stage of a two-part programme costing 1.3 billion euro (£1.09 billion), is due to land a rover on the Red Planet in 2021 to drill into the Martian soil and look for biochemical traces of living or dead microbes.

    European science ministers decided to back the mission at a pivotal ESA council meeting in Lucerne, Switzerland.

    “Today I am very confident that we will do it,” said the space agency’s director general, Jan Worner. “We need to work hard because it’s not only some rover, we have the payloads from different sources – all of this has to pack together. It’s not an easy thing, but we are confident that we will succeed.”

    However he said there had been “no free ticket” from the member states. ExoMars would, at least initially, “eat up” the whole of a 1 per cent per year increase in ESA’s science budget, which was also agreed at the meeting.

  7. #97
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    I do hope they get the altimeter/motion sensing correct so the surface mission will have a chance of success.

  8. #98
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    It turns out that a different division of my employer manufactures the IMU, and the history of the device will be presented in an upcoming technical lecture. If I can successfully log into the lecture, I'll post if they say anything interesting about ExoMars (that isn't proprietary). BTW: it appears that the device has been in "high rate production" since 1994, so you'd expect a lot of understanding as to its limitations.


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  9. #99
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    Well, I learned that a competitor's IMU was used on ExoMars.


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  10. #100
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    ESA has signed the contract to complete its construction of the ExoMars 2020 for a 2020 launch.

    http://www.esa.int/Our_Activities/Sp...g_ExoMars_2020

    The first ExoMars mission arrived at the Red Planet in October and now the second mission has been confirmed to complete its construction for a 2020 launch.

    ESA and Thales Alenia Space signed a contract today that secures the completion of the European elements of the next mission.

  11. #101
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    Emily Lakdawalla on the photo of Phobos from ExoMars' camera, the Colour and Stereo Surface Imaging System (CaSSIS).

    http://www.planetary.org/blogs/emily...er-phobos.html

    ExoMars Trace Gas Orbiter's science team enjoyed the opportunity in November to test out their science instruments on Mars. The spacecraft entered orbit successfully in October, but needs to spend a year adjusting its trajectory, gently dipping into Mars' uppermost atmosphere to dump velocity and achieve a lower, more circular orbit. No science will be possible during this aerobraking period. To appease the science team's appetites for data (and, more importantly, to make sure everything was still fine after the rigors of orbit insertion), the mission provided the science team the opportunity to use two orbits to operate their instruments.

    ESA released some early results from several instruments in a web article on November 29. But the thing I was most excited to see was the new images of Phobos from ExoMars' camera, the Colour and Stereo Surface Imaging System (CaSSIS). And they didn't disappoint. The photo is fuzzy because it's been blown up a lot, but it's in color (yay!) and it shows a face of Phobos that we don't often get to see.

  12. #102
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    They have chosen two possible landing sites for ExoMars.

    http://www.esa.int/Our_Activities/Sp...g_sites_chosen

    After a two-day meeting with experts from the Mars science community, industry, and ExoMars project, during which the scientific merits of the three sites were presented alongside the preliminary compliance status with the engineering constraints, it was concluded that Mawrth Vallis will be the second site to be evaluated in more detail.

    Around a year before launch, the final decision will be taken on which site will become the ExoMars 2020 landing target.

    All of the sites lie just north of the equator, in a region with many channels cutting through from the southern highlands to the northern lowlands. As such, they preserve a rich record of geological history from the planet’s wetter past billions of years ago, and are prime targets for missions like ExoMars that are searching for signatures of past life on Mars.

  13. #103
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    The MOMA laser has reached the first milestone - delivery of the laser head to the NASA Goddard Space Flight Center, USA.

    http://www.marsdaily.com/reports/Fro..._2020_999.html

    A major goal of the ExoMars mission is to search for past or present life on the Earth-like planet. One of the most important analytical instruments of the EXOMARS rover is the "Mars Organic Molecule Analyzer", MOMA for short. This is being developed together with further partners under the leadership of the Max Planck Institute for Solar System Research (MPS), Gottingen, Germany.

    The MOMA laser model, which has been delivered to the NASA Goddard Space Flight Center, is part of the Laser Desorption Mass Spectrometer (LD-MS) developed there. On Mars, it can identify and analyze organic matter. Organic molecules in the soil samples taken in situ could provide clues to possible forms of life.

  14. #104
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    Exomars 2016 is positioning itself for its science mission.

    http://spaceflight101.com/trace-gas-...s-aerobraking/

    "ESA’s Trace Gas Orbiter circling Mars since October 2016 this week finished a delicate aero-braking campaign of nearly one year that moved the spacecraft from a highly elliptical orbit into a nearly circular Low Mars Orbit in preparation for a final set of trimming maneuvers and the start of a highly anticipated science mission. As the primary component of the ExoMars 2016 mission, the orbiter now sets out on a science mission of at least four years and it builds an orbital relay point for rovers exploring the Martian surface."


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  15. #105
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    ExoMars is almost ready to start measuring how much methane is in the Martian atmosphere,

    https://spaceflightnow.com/2018/03/0...ience-mission/

    Nearly a year-and-a-half after arriving at the red planet, Europe’s ExoMars orbiter is finally approaching a planned perch around 250 miles over the rust-colored world after repeatedly dipping into the Martian atmosphere to lower its orbit.

    The end of a year-long “aerobraking” campaign moves the ExoMars Trace Gas Orbiter closer to starting regular science observations, a transition expected in April, when the mission will begin measuring how much methane is in the Martian atmosphere, an indicator of potential ongoing biological or geological activity.

    Built in Europe and launched by a Russian Proton rocket in March 2016, the Trace Gas Orbiter is the first mission in the two-part ExoMars program, a partnership between the European Space Agency and Roscosmos, Russia’s space agency. An ExoMars lander and rover are scheduled for launch to the red planet in 2020.

  16. #106
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    ESA has released a photo taken by the Trace Gas Orbiter.

    https://timesofindia.indiatimes.com/...w/63930229.cms

    The European Space Agency has released the first image taken by its Trace Gas Orbiter showing the ice-covered edge of a vast Martian crater.
    Scientists combined three pictures of the Korolev Crater taken from an altitude of 400 kilometers (249 miles) on April 15.
    Lead researcher Nicolas Thomas said Thursday the colors in the resulting image were also adjusted to best resemble those visible to the human eye.

  17. #107
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    "Roscosmos postpones joint ESA ExoMars mission after failed parachute tests"

    http://www.marsdaily.com/reports/Ros...Tests_999.html

    Russian State Space Corporation Roscosmos said in a statement on Thursday that the launch of the joint Russian-European ExoMars-2020 astrobiology mission, aimed at searching for evidence of life on Mars, had been postponed after the recent failure of tests of the parachutes needed for the landing.

    "The launch of the ExoMars-2020 mission is planned to take place during the 'astronomic window' from July 26-August 13, 2020, with landing on Mars scheduled for March 2021," Roscosmos said.

    Meanwhile, Roscosmos chief Dmitry Rogozin has previously said that the joint mission of Roscosmos and the European Space Agency (ESA) will be launched on July 25, 2020.

    A source told Sputnik last week that tests of the parachutes, developed in Europe, failed on August 5 in Sweden. The ESA confirmed the information, specifying that the parachute canopies had been damaged. New tests are expected to be held before 2019 end and also in 2020.
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