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Thread: NASA's moon mission - ARTEMIS

  1. #151
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    Quote Originally Posted by cannongray View Post
    I thought the production of SLS is delayed due to the pandemic when NASA announced the coronavirus has become the reason for the suspension of work of SLS and the Orion ship.
    SLS has suffered from so many developments problems, hardware and software, that the coronavirus delays are minor in comparison (it was supposed to launch in 2016). Now they've found comparability issues (rumor: vibrations, etc.) such that it may not be able to launch Europa Clipper without damaging it.

    Because of these there's new language in the NASA appropriations bill that if SLS is not "available" they can launch it commercially (likely Falcon Heavy with a Star-48 kick stage.)

    Edit: IMO vibration issues aren't a big surprise. Back in the Constellation program a similar large solid was to be used for Ares 1's first stage when launching Orion. Vibrations from thrust oscillations, common in long solids, were quite a problem.

    https://www.nasaspaceflight.com/2008...state-of-play/
    Last edited by docmordrid; 2020-Dec-27 at 01:43 AM.

  2. #152
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    SpaceX, Blue Origin, Dynetics await NASA lunar lander decision. The three space firms were selected in April to submit proposals early this month. Having done that, they now await NASA's decision, which is scheduled for February. The space agency has indicated it could pick one or two of the proposals.

    https://www.moondaily.com/reports/Sp...ision_999.html
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  3. #153
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    From what I’ve seen, my preference would be Dynetics and SpaceX. The “National team” lander (Blue Origin is just one of the companies involved) isn’t reusable and doesn’t strike me as a very good concept. It gives me a “horse designed by committee” impression. The Dynetics design is reusable aside from drop tanks, and it is more conventionally sized, and to me looks like a good concept for a new lunar lander. The SpaceX rocket is big, and they would need to get in-space refueling working, so it probably has more technical concerns than the others, but also would be fantastic if they got it working.

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  4. #154
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    Quote Originally Posted by Van Rijn View Post
    From what I’ve seen, my preference would be Dynetics and SpaceX. The “National team” lander (Blue Origin is just one of the companies involved) isn’t reusable and doesn’t strike me as a very good concept. It gives me a “horse designed by committee” impression. The Dynetics design is reusable aside from drop tanks, and it is more conventionally sized, and to me looks like a good concept for a new lunar lander. The SpaceX rocket is big, and they would need to get in-space refueling working, so it probably has more technical concerns than the others, but also would be fantastic if they got it working.
    I would say the Dynetics lander makes sense for the exploration phase while the Lunar Starship would make sense if/when large scale infrastructure is being built. Unfortunately I suspect lobbying power may favour the National team.

  5. #155
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    I don't understand why astronauts are supposed to descend long ladders with high risk of losing their grip or slipping, then falling a long way. That makes absolutely no sense to me.

    This option was examined and discarded during the earliest part of the Apollo era, when lunar landers were envisioned that were shorter than the taller landers shown now (direct ascent lander, combining CSM and LEM in one). Von Braun himself wrote a landing-on-the-moon story about 1960 in which an astronaut falls from a very high descent ladder and is injured.
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  6. #156
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    Maybe they can use a cabled platform, like window washers?
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  7. #157
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    Quote Originally Posted by Noclevername View Post
    Maybe they can use a cabled platform, like window washers?
    The concept images I’ve seen show just that.

    https://cdn-mos-cms-futurecdn-net.cd...BZ-1200-80.jpg

    How workable that might be is up for debate.

  8. #158
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    Quote Originally Posted by schlaugh View Post
    The concept images I’ve seen show just that.

    https://cdn-mos-cms-futurecdn-net.cd...BZ-1200-80.jpg

    How workable that might be is up for debate.
    I think Roger E. Moore was referring to the National Team design that has an alarmingly long ladder.

  9. #159
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    Quote Originally Posted by Garrison View Post
    I think Roger E. Moore was referring to the National Team design that has an alarmingly long ladder.
    Both Blue Origin and SpaceX landers have been depicted with "alarmingly long" ladders. SpaceX's lander, as mentioned, also has a cabled platform, which leaves from an open bay about 10, maybe, stories above the lunar regolith. Lunar astronauts tend to do a little hop-skip trot when they are moving fast, which will not work inside the open-door bay as you won't be able to stop if you end up heading for the open bay door.

    That cable better not jam or break, BTW.

    .
    Last edited by Roger E. Moore; 2020-Dec-28 at 03:29 PM.
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  10. #160
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    Here is an example of a proposed Apollo lander from about 1961, taken from an online Apollo history published by NASA. You can see the astronauts would have to descend a ladder from 6 stories up. This is exactly the design being proposed by Blue Origin, which combines the CSM (now the ascent stage) and descent stage from the old lander proposal.

    It is going to stink when we lose astronauts in accidents caused by bad spacecraft design, but hey, what do I know. It's not like we are landing on an asteroid with practically no gravity at all. If an Apollo astronaut fell while trotting on the ground, it was considered a major issue until the astronaut got back up and was okay.
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  11. #161
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    Quote Originally Posted by Roger E. Moore View Post
    Both Blue Origin and SpaceX landers have been depicted with "alarmingly long" ladders. SpaceX's lander, as mentioned, also has a cabled platform, which leaves from an open bay about 10, maybe, stories above the lunar regolith. Lunar astronauts tend to do a little hop-skip trot when they are moving fast, which will not work inside the open-door bay as you won't be able to stop if you end up heading for the open bay door.

    That cable better not jam or break, BTW.
    I mentioned this before (maybe earlier in this thread) but highly-abrasive lunar dust is going to be a major issue for long-term surface exploration. Designers of these platform systems will need to take that into consideration.

    From the linked article:

    After walking on the moon in 1969, for example, Apollo 12 astronaut Pete Conrad said one of the worst problems his crew faced was dust. He called it "one of the most aggravating, restricting facets of lunar surface exploration" due to its "restrictive friction-like action to everything it gets on.”

    And it wasn’t just spacesuits that got affected by the dust. China’s Yutu-1 rover came to a standstill after a couple of months on the moon, and most scientists agree it was likely dust that caused the problem. The dust has a nasty tendency to stick in joints and in mechanical parts and to wear away even tough substances. One Apollo moon mission lost part of a rover fender due to dust abrasion, for example.

  12. #162
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    Quote Originally Posted by Roger E. Moore View Post
    Both Blue Origin and SpaceX landers have been depicted with "alarmingly long" ladders.
    I appear to have been wrong about SpaceX's lander ladder, as I cannot find an illustration of it. Must have been confused. Here's one of the Starship as a lunar lander, almost the same as proposed lander itself. That 10-story drop, give or take, from the cabled platform and open bay door is going to hurt.
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  13. #163
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    The "National Team" lander from Blue Origins. That really is a scary drop, but shorter than a fall from a Starship or SpaceX lander bay.
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  14. #164
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    Here is an illustration from Wernher von Braun's "First Men to the Moon" novella from 1960. In the background to the upper right is the lander, which has a USAF reentry spacecraft on top. The two crewmen sat in the cockpit in the uppermost part, behind the nose. Note the bay door and crane, similar to the SpaceX proposal. I am guessing that the height of the ladder (too hard to see, if it is shown here) was over 100 feet, give or take.
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  15. #165
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    The actual SpaceX moon lander. How do you keep it from falling over if it lands on an uneven surface or on rocks? These big-and-tall designs don't look steady on their feet. Apollo 11 almost landed on boulders, so the question is nontrivial. I think I asked this question before here but cannot recall the response.
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  16. #166
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    For the heck of it, here is the cancelled Altair moon lander from the old Constellation program. Note the railings for the ladder, about 3 stories high. Top of lander not railed, however, and a fall is possible.
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  17. #167
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    Quote Originally Posted by schlaugh View Post
    I mentioned this before (maybe earlier in this thread) but highly-abrasive lunar dust is going to be a major issue for long-term surface exploration. Designers of these platform systems will need to take that into consideration.
    Similar article on same topic, the damaging properties of moon dust when it gets into machines.

    https://spacenews.com/dealing-with-d...-moon-dilemma/
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  18. #168
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    People stand near the edge of an open cargo bay of military cargo planes -in flight. If you can design a craft to go to the moon, you can design railings and tethers to make it reasonably safe as well. And yes, those mechanisms should not jam or break, just like any other mechanism on a rocket. Hence the "best part is no part" design philosophy of Musk.

    Designing a tall lander that would not tip over is more of a challenge, but it's already on SpaceX's agenda.
    With sufficient thrust, water towers fly just fine.

  19. #169
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    Quote Originally Posted by Nicolas View Post
    People stand near the edge of an open cargo bay of military cargo planes -in flight.
    I recall that these people will once in a while fall out. I don't think this will be tolerated on a moon mission as it might be in the USAF.
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  20. #170
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    A spiral staircase or ramp around the outside of SpaceX’s proposal would be nice, although not very aerodynamic. I guess it would have to pass through Earth’s atmosphere at least once.
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  21. #171
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    Presidential transition, weak funding put 2024 moon landing goal in doubt.

    https://www.moondaily.com/reports/Pr...doubt_999.html
    Do good work. —Virgil Ivan "Gus" Grissom

  22. #172
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    Dynetics design looks safe, not much of a fall hazard there.

  23. #173
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    GAO has again reamed NASAs backside over SLS & Orion. Costs, more delays, and the current ones do not take into account those caused by CoVid-19.

    Summary,

    https://www.gao.gov/products/GAO-21-105#summary

    >
    The National Aeronautics and Space Administration (NASA) again delayed the planned launch date for Artemis I, the first uncrewed test flight involving three closely related human spaceflight programs—the Orion crew vehicle, Space Launch System (SLS), and Exploration Ground Systems (EGS). Together, these programs aim to continue human space exploration beyond low-Earth orbit. The most recent delay, to November 2021, resulted in part from manufacturing challenges and represents a 36-month slip since NASA established a schedule to measure performance in 2014. This new launch date does not account for the effects of COVID-19. According to NASA officials, COVID-19 delays and schedule risks will place pressure on NASA's ability to achieve this launch date.

    Development cost estimates for key programs also increased. The cost of the SLS program increased by 42.5 percent and the EGS program by 32.3 percent since 2014, for a combined increase of over $3 billion, bringing the total to $11.5 billion. NASA does not plan to complete revised estimates for Orion, which are tied to the second, crewed test flight (Artemis II) before spring 2021.
    >

  24. #174
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    Quote Originally Posted by Roger E. Moore View Post
    Both Blue Origin and SpaceX landers have been depicted with "alarmingly long" ladders. SpaceX's lander, as mentioned, also has a cabled platform, which leaves from an open bay about 10, maybe, stories above the lunar regolith. Lunar astronauts tend to do a little hop-skip trot when they are moving fast, which will not work inside the open-door bay as you won't be able to stop if you end up heading for the open bay door.

    That cable better not jam or break, BTW.

    .
    It's an elevator - attached to the fuselage at 2 rails and with cables doing the outboard end, much like many construction elevators. If they're hopping on a moving platform elevator they need more training.

    Starship's elevator concepts. Note the fuselage rails.

    Lunar Starship cargo - elevator 1024_crop.jpg

    HLS Lunar Starship 1.jpg
    Last edited by docmordrid; 2021-Jan-05 at 10:17 PM.

  25. #175
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    SLS Green Run (8 minute static fire) NET January 17.

    They had trouble with high LOX temps during both wet dress rehearsal attrmpts. Any odds on it screwing up?

    http://spaceref.com/sls/space-launch...scheduled.html

  26. #176
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    It will not screw up. They can't afford to screw up as it's mission hardware. Any sign of something not going according to the simulation, and they'll call it a day -again. They are developing a baby car seat and have to test everything with a real baby instead of writing off a few dolls and old cars.
    With sufficient thrust, water towers fly just fine.

  27. #177
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    And if you think the above was overstating it: the SLS core has been standing on that test stand for a full year. A YEAR. And the closest they have come was a wet dress rehearsal unil "a few minutes" before ignition.
    With sufficient thrust, water towers fly just fine.

  28. #178
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    Quote Originally Posted by Nicolas View Post
    And if you think the above was overstating it: the SLS core has been standing on that test stand for a full year. A YEAR. And the closest they have come was a wet dress rehearsal unil "a few minutes" before ignition.
    And lets not forget the shaky condition of the Orion after the partial failure of a PDU, which they've decided not to fix because it would take up to a year!

  29. #179
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    Quote Originally Posted by Nicolas View Post
    And if you think the above was overstating it: the SLS core has been standing on that test stand for a full year. A YEAR. And the closest they have come was a wet dress rehearsal unil "a few minutes" before ignition.
    Closer to 11 months, but what is a month or so?
    https://spaceflightnow.com/2020/02/0...n-mississippi/

  30. #180
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    Plus a few weeks to take it from the factory to the test stand and it's still at least 10 days before the static fire attempt... You know those dreams where you try to move fast but move like you're in thick soup? That's what this program is made of. Not people working slowly. People trying to work normally in an environment that doesn't allow for it.
    With sufficient thrust, water towers fly just fine.

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