back to article After lunar orbit trip NASA's Orion capsule is on its way back home

NASA's Orion capsule, designed to send the next crew of astronauts to the Moon, is heading back to Earth after spending some time in a distant retrograde orbit above the satellite's surface. The spacecraft fired its main engine on December 1 at 1553 CST (2153 UTC) for one minute and 45 seconds, changing its velocity by about …

  1. Mike 137 Silver badge

    incredible accuracy

    "when the floating capsule will be 79.2 miles from the Moon's surface"

    0.2 of a mile is 352 yards (≈322 m). Especially as a prediction, that's pretty fine resolution in the context of the lunar surface.

    1. Joe W Silver badge

      Re: incredible accuracy

      "changing its velocity by about 454 feet per second,"

      Sounds like the numbers got converted from metres. That would have been 135 m/s.

      Those oddly precise numbers usually have that kind of origin, the writer just converting numbers and not thinking about the precision of the measurement converted from. You see that all the time.

      When woodworking I mostly mark directly from the related parts (so I do not have to measure). Thus converting 4" to 10cm, or 1/2 " to 12mm works. Those numbers were not precise enough to care about exact conversions in the beginning. For any fitting of parts:don't measure. Mark directly.

      1. Red Ted
        FAIL

        Re: incredible accuracy

        Definition of accuracy:

        Measure with a micrometer,

        Mark with chalk,

        And finally, cut with an axe.

        1. Potemkine! Silver badge
          Headmaster

          Re: incredible accuracy

          4) a song by The Cure from the album 'Three Imaginary Boys"

          == Bring us Dabbsy back! ==

      2. Sceptic Tank Silver badge
        Childcatcher

        Re: incredible accuracy

        Somehow I'm glad you're not fitting the airlock.

    2. Irony Deficient

      Re: incredible accuracy

      I agree with Joe W above; 79.2 miles is most likely 127.5 km rounded to the nearest tenth of a mile, and an accuracy of 0.5 km is a bit under 2½ furlongs (≈ 100 rods or 550 yards).

    3. vapoureal

      Re: incredible accuracy

      Pendantic point - I could be wrong but I believe that the navigation is done in nautical miles. 0.2 nm = 400 yards. Maybe they'd best stick to metres, but then the US taxpayers wouldn't get that. Jus' sayin'...

      1. Richard 12 Silver badge

        Re: incredible accuracy

        NASA are entirely metric, except for their PR department.

        They learned this after smashing a probe into Mars by mistake.

        1. zuckzuckgo
          Thumb Up

          Re: incredible accuracy

          > They learned this after smashing a probe into Mars by mistake.

          Where they originally trying for Uranus?

          1. Anonymous Coward
            Anonymous Coward

            Re: incredible accuracy

            Not mine I hope!

      2. ThatOne Silver badge
        Devil

        Re: incredible accuracy

        > I believe that the navigation is done in nautical miles

        Actually "space miles", of which the exact definition is only known by a retired engineer currently residing in some unspecified monastery in Tibet...

        Why use clearly defined scientific units when you can use whatever takes your fancy, ideally without telling anybody about it? Freedom, man!

  2. bob, mon!
    Boffin

    unbelieveable accuracy

    "Orion carries a trusty bit of equipment leftover from NASA's Space Shuttle era, its main engine, capable of providing 6,000 pounds (over 2,721 kilograms) of thrust "

    Other sources suggest that the Space Shuttle's main engine provided as much as 470,000 pounds of thrust. One document does mention the "Orbital Maneuvering System Engines" producing 6,000 pounds of thrust.

    1. gecho

      Re: unbelieveable accuracy

      Yes it's an OMS engine not an SSME.

    2. Charlie van Becelaere

      Re: unbelieveable accuracy

      "Orion carries a trusty bit of equipment leftover from NASA's Space Shuttle era, its main engine, capable of providing 6,000 pounds (over 2,721 kilograms) of thrust "

      My question here was the units of thrust. Kilograms? Shouldn't that be Newtons?

  3. Gene Cash Silver badge

    Working flawlessly - and stultifyingly boring

    So I've been a "space nut" for 55 years and the NASA coverage has been worse than watching paint dry. For engine firings, you don't even see the engines. There's maybe a puff of vapor from somewhere and some jiggling. They barely explain what you're seeing - "is that round thing the Earth? The Moon? Vulcan? a Death Star?"

    They don't explain the mysterious bouncing of the ship between configurations is when you have telemetry (the real config) and don't have telemetry (some sort of stupid default, instead of keeping the last known values)

    The trajectory explanation stuff is so dumbed down, even I don't recognize it.

    They don't explain or even have a labeled graphic of what the pieces-parts-bits on the spacecraft are.

    Then there's about every 15 minutes an announcement how this will support the landing of the first woman and the first person of color on the moon. Which is fine, but it does not need to be repeated every 15 minutes, thank you very much.

    This is not how you win taxpayer funding.

    1. Flocke Kroes Silver badge

      Re: Working flawlessly - and stultifyingly boring

      NASA used to have a budget for education but it got cancelled. The problem with letting people go off script in a NASA broadcast is they may say something educational like Orion already did entry/descent/landing in 2014 and SLS was originally supposed to launch in 2017.

      1. Richard 12 Silver badge

        Re: Working flawlessly - and stultifyingly boring

        They're being really stupid with the broadcasts though.

        Orion has a pile of cameras transmitting live video, yet they barely used then in the stream, instead they had an automated sequence showing a brief blip from some of them before jumping to a static logo graphic for around 90% of the time.

        Just stream the cameras with an overlay of some telemetry.

        1. Apollo-Soyuz 1975

          Re: Working flawlessly - and stultifyingly boring

          Bandwidth becomes a bit of a problem with a craft that far from Earth. Remember that all of the fantastic footage from the Apollo flights was recorded on 16 mm film that had to be bright back and developed after the fact. The video footage beamed back from the lunar EVAs was either a) not very fantastic (in terms of resolution), or b) transmitted from a collapsible high-gain antenna that was too large to bolt to the side of the lunar lander and required manual setup by the crew.

    2. Totally not a Cylon
      Boffin

      Re: Working flawlessly - and stultifyingly boring

      You want real scientific talk?

      go look up NasaSpaceflight on Youtube.

      They let real scientific types talk out loud and unscripted..... LIVE!

      1. Grey_Kiwi

        Re: Working flawlessly - and stultifyingly boring

        Remember, when watching their excellent YouTube videos and their live streams, that NASASpaceFlight.com is a fan site, nothing to do with the National Aeronautics and Space Administration. That's why NASASpaceFlight's presenters can say what they like instead of sticking to a PR department script

        1. Totally not a Cylon

          Re: Working flawlessly - and stultifyingly boring

          Which is why they also have excellent side discussions about how to cook bacon and whether pineapple belongs on pizza.....

    3. psychopomp

      Re: Working flawlessly - and stultifyingly boring

      I mean, really. who has never experienced that? Sorry... forgot where I was...

    4. Annihilator

      Re: Working flawlessly - and stultifyingly boring

      “For engine firings, you don't even see the engines. There's maybe a puff of vapor from somewhere and some jiggling.”

      To be fair, it’s the vacuum of space. Rocket firings aren’t the big Hollywood bursts of flame, they’re monomethylhydrazine reactions.

      1. The Oncoming Scorn Silver badge
        Flame

        Re: Working flawlessly - and stultifyingly boring

        I don't know, I find the Falcon engines bells glowing "white hot" when firing in orbit, pretty damn spectacular.

        https://pbs.twimg.com/media/Dz-bR1oWwAAGzdn.jpg

        Icon - Look just rotate it left by 90 degrees in your heads OK.

  4. navidier

    "is expected to land and splashdown in the Pacific Ocean"

    Did anyone else experience a moment of cognitive dissonance trying to imagine those two actions happening simultaneously?

    1. The commentard formerly known as Mister_C Silver badge

      Re: "is expected to land and splashdown in the Pacific Ocean"

      Covering all the bases perhaps?

      They hope to splash down, but accept that they might miss the big, big ocean and hit a teeny tiny bit of island by mistake...

      1. Sp1z

        Re: "is expected to land and splashdown in the Pacific Ocean"

        I'm getting Lilo and Stitch vibes from this comment

  5. vapoureal

    'Terra Firma'

    They need to make up their minds - is it the Pacific or 'terra firma' for the return of the astronauts (who might have an opinion on that). Or maybe it's just loose journalism...

    1. Timbo

      Re: 'Terra Firma'

      I do not think that Artemis is "validated/approved" to make a landing on "land"...so the use of "terra firma" must be a (sloppy) reference only to the planet Earth.

      1. Richard 12 Silver badge

        Re: 'Terra Firma'

        Terra Humidum?

        1. ThatOne Silver badge

          Re: 'Terra Firma'

          Terra Molla?

          1. WolfFan

            Re: 'Terra Firma'

            Agua Fria.

            1. Neil Barnes Silver badge

              Re: 'Terra Firma'

              Agua calliente if they get the landing wrong!

              1. Irony Deficient

                Re: ‘Terra Firma’

                In the apt phrasing of Virgil,

                maria undique et undique caelum

                (“seas on all sides and on all sides the sky”).

    2. Death Boffin
      Flame

      Re: 'Terra Firma'

      Given that Mauna Loa is erupting again, it could be both. (How well will the heat shield withstand lava?)

  6. Swordfish1

    Waste of money, as most of it is not re-usable. The idea is great, and its great to see that after all these years, NASA is planning to send astronauts back to the moon, hopefully establishing a permanent base. But to cut costs, the main stage and boosters have to be re-usable. Space X has already proven that with Falcon 9. Cant wait until they prove it with Starship as well.

    1. DJO Silver badge

      A lot of the bits have been recycled, loads of second hand shuttle parts, just this is their last use - rocket motors have a finite life and it's not a lot of firings.

      To make something as large as the SLS return to the ground would require a lot more testing than SpaceX and it took them 20 failures before they got one to work and a few more crashes to refine it. Just imagine what people (such as yourself) would have said if NASA had pointlessly crashed at least 20 SLS stacks trying to get one to land. It would make no economic sense unless they were planning to launch hundreds of SLS stacks which was never the plan - the current plan is for 5 launches so wasting 20+ rockets just to try to save 5 rockets would be a insane waste of money.

  7. Sceptic Tank Silver badge

    Lunacy

    Still don't see how being locked up in a tin can and being cooked by interstellar radiation for 10 days is going to be fun on the next mission. But then, waking up with the moon shining through your bedroom window could have its charms.

    1. Anonymous Coward
      Anonymous Coward

      Re: Lunacy

      They’re still within the Earth’s magnetosphere, you know …

    2. The Oncoming Scorn Silver badge
      Coat

      Re: Lunacy

      Unless you are a insomniac.

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