back to article ESA's ExoMars Trace Gas Orbiter blasts itself closer to the Red Planet

The European Space Agency’s ExoMars Trace Gas Orbiter has successfully completed its engine burn and is on track to enter orbit around Mars on 19 October. The engine burn has been dubbed “deep-space manoeuvre 1” and is one of the most critical stages in the first mission of the ExoMars programme. A large amount of thrust is …

  1. pdh

    Why is this the only thing we care about?

    > The fascination with the Red Planet is driven by tantalising evidence that life may have once existed

    This has always bothered me. I'd still be very interested in, and very impressed by, these remote exploratory missions even if we were absolutely 100% certain that life had never existed on other planets. I wonder sometimes whether we're missing out on other significant discoveries because of this over-focusing (in my opinion) on the Search for Extra-Terrestrial Life. Was there ever life on other planets in our solar system? That's a very interesting question, but it's not the only very interesting question.

    1. Mark 85

      Re: Why is this the only thing we care about?

      I think it's a stepping-stone approach. We've landed (hard and bounced but landed) on a comet and walked on the moon. Both, with no atmosphere and rather lifeless. We can do that. But Mars has an atmosphere (ok.. not much... granted) and gravity.

      Mars gives us an opportunity to fine tune the landings and the exploration vehicles. Other than Mars, the only other chance for finding life* seems to be outside the solar system which will take some pretty extreme engineering and project life (time) to accomplish.

      If we don't discover life, I'd like to think we want to find a planet that can support our life form. Finding is one thing, getting there and landing is another.

      *Life as we define it. Might be life elsewhere that's not carbon based.

      1. BristolBachelor Gold badge

        Re: Why is this the only thing we care about?

        "Other than Mars, the only other chance for finding life* seems to be outside the solar system..."

        Well there are some indications that the moons on the gas giants could also harbour life, especially the icy moons of Jupiter - Hence the JUpier ICy moons Explorer project (JUICE). Now that project is really pushing the space engineers (the rocket scientists not so much); very remote, hardly any power from the solar arrays, eclipses that put other eclispses to shame many times over, radiation levels that literally cook the electronics...

    2. You aint sin me, roit

      Re: Why is this the only thing we care about?

      It would have very profound implications if we found life, or evidence of past life, on Mars. It would mean that there is life in the universe apart from on Earth. It would imply that life is probably quite abundant - originating on the both of the realistic candidates for life as we know it.

      And it's not as if the chemical analysis of soil samples will only provide indications of life on Mars. Indeed the whole mission will do more than just test for signs of life - the lander will study Martian weather.

      We already know a great deal about Mars - what other interesting questions do you want to see asked?

  2. Alistair
    Pint

    @pdh

    While I and quite a few others here will agree in general principle with the core of your argument, I think that the general pool of the populace don't have the same fascination with the finer points of these projects, so publicity wise it sells *very* well to do the 'alien life forms' tag out there.

    Me, I'm loving the remote, self directed automation for landings. It just completely blows my mind that the "Rocket Scientists" get it right so often. Mostly since I get to see what is supposed to be automation in the IT world get it *wrong* so damned often.

    I grew up remembering fuzzy black and white images of Apollo 11 on tv, and watching Voyagers and Mariners, the Shuttle and the first tiny bits of 'space station' go up. This stuff with New Horizons and Juno and whatnot will keep my youngest's imagination fired up as he gets older.

    Beer for a well prepared Mars orbital entry.

  3. ma1010
    Thumb Up

    We're also learning other things

    It's not only about steering spacecraft, although we all know that's quite important. We are also learning a lot of good things about propulsion systems. The reason we can maneuver spacecraft like this is because of ion engines. Even though the concept is quite old, these engines have been practical for only a few years.

    According to my back-of-the-envelope calculations, the spacecraft was accelerating at only about .011 G (just a hair over 1/10 m/sec), which may not sound like much, but the very idea of having a rocket engine that can be started and stopped and can keep running for 50 minutes (not to mention having fuel for future burns) is amazing to those of us who remember some of the constraints previous engines had. As far as we know now, Ion engines offer MUCH greater fuel efficiency per Newton than anything short of full-on nuclear engines of some kind. My hat's off to the rocket scientists who made those engines practical.

    1. Anonymous Coward
      Anonymous Coward

      Re: We're also learning other things

      I think you may be wrong about it being an ion engine. Those typically give thrust in tiny amounts over months of time, and could never deliver 0.1g. Must have been a small standard chemical thruster.

  4. johannsebastianbass

    @Big John You are correct on the propulsion. The engine used is a (liquid-)bi-propellant engine delivering 424 Newtons of thrust.

    The numbers quoted, however, are not The entire mass of the thing being 4332 kilograms, the acceleration (or rather deceleration, in this case ) equals 424 / 4332 = 0.098 m sec-2, which is about 0.0099 g.

    1. DNTP

      More engine information

      According to internet sources, the S400-15 bi-propellent primary engine burns monomethyl hydrazine (MMH) as a fuel. (I call it 1-methyl hydrazine which is technically correct but stylistically inappropriate because hydrazine, the base, is not an organic compound). The oxidizer is probably nitrogen tetroxide, a proven combination used in other applications such as the Space Shuttle orbital maneuvering system.

      The given vacuum specific impulse for the ExoMars TGO engine is 330 seconds, which is admirably efficient relative to the evolution of human spaceflight. For comparison, the Space Shuttle OMS operated at about 313-316 seconds (out of a theoretically possible 336), and there's no reason to assume the ESA and Airbus engineers aren't every bit as good as their American counterparts.

      1. johannsebastianbass

        Re: More engine information

        @DNTP Agreed. 330 seconds of specific impulse is squarely brilliant. Thanks for fishing that from the internets.

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