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Thread: NASA's moon mission - ARTEMIS

  1. #271
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    Hydrogen is environmentally clean, depending on how you generate it. But that argument becomes totally irrelevant if you need SRB's on either side of them.
    With sufficient thrust, water towers fly just fine.

  2. #272
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    Quote Originally Posted by Nicolas View Post
    Hydrogen is environmentally clean, depending on how you generate it. But that argument becomes totally irrelevant if you need SRB's on either side of them.
    Given that almost all hydrogen today is produced from fossil fuel (usually natural gas) it currently has no practical advantage over a methane fuel rocket. In any case, flight rates would have to be radically higher before they had a significant effect on CO2, like thousands of Starships flying constantly. If they get that far, maybe then a rethink will be in order. For the same reason, I’m not concerned about SRBs either. Yes, they aren’t great, but they will never be part of a launcher with a high flight rate. Too expensive, for one thing.

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  3. #273
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    Absolutely true, if you burn gas to create H2 you might as well fly on methane, environmentally speaking. OK, the H2 plant might have better filters than the rocket engine, but in the quest for efficiency a rocket engine will aim to burn as perfect as possible anyway.

    When rockets fly regularly -and reusably- they will get regulations just like ships and planes have today and things will sort themselves out. Until that point, let's get the technology on point first and then make it sustainable next. Besides, going for a steel build and reusable rockets already is a very good step towards sustainable rocketry we're currently taking.
    With sufficient thrust, water towers fly just fine.

  4. #274
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    Quote Originally Posted by publiusr View Post
    Webb is even more costly because we didn't have an HLLV to allow monolithic simplicity-and Starship-SuperHeavy looks to be expendable for the near future. What is really stupid is to limit SLS to Orion-which will have an escape tower BTW. I want big hydrogen infrastructure and the greater specific impulse. The SLS workers deserve the same love and respect that JPL and others get without people trying to slit their throats.
    publiusr

    Take it down a notch. The last sentence is way over the line.
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  5. #275
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    Quote Originally Posted by Nicolas View Post
    Absolutely true, if you burn gas to create H2 you might as well fly on methane, environmentally speaking. OK, the H2 plant might have better filters than the rocket engine, but in the quest for efficiency a rocket engine will aim to burn as perfect as possible anyway.

    When rockets fly regularly -and reusably- they will get regulations just like ships and planes have today and things will sort themselves out. Until that point, let's get the technology on point first and then make it sustainable next. Besides, going for a steel build and reusable rockets already is a very good step towards sustainable rocketry we're currently taking.
    Methane can also be produced from hydrogen and CO2, and doing so is easy enough that it may be an economical approach storing energy given the storage issues of hydrogen. Rockets burning such methane would actually be slightly carbon-negative.

    But it's going to take several orders of magnitude more rocket flights before that actually makes a difference. Look at LNG storage tanks for an idea of the scale of current usage. You think Starship's big? https://stateimpact.npr.org/pennsylv...e-LNG-tank.jpg

  6. #276
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    Quote Originally Posted by cjameshuff View Post
    Methane can also be produced from hydrogen and CO2, and doing so is easy enough that it may be an economical approach storing energy given the storage issues of hydrogen. Rockets burning such methane would actually be slightly carbon-negative.

    But it's going to take several orders of magnitude more rocket flights before that actually makes a difference. Look at LNG storage tanks for an idea of the scale of current usage. You think Starship's big? https://stateimpact.npr.org/pennsylv...e-LNG-tank.jpg
    In comparing methane versus RPG, yes. In comparing with hydrogen, absolutely no as that combustion results in water. Yes hydrogen has storage issues.

  7. #277
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    If you make methane from hydrogen and CO2 rather than using fossil methane, and both the hydrogen creation and methane creation were carbon neutral, you would be carbon negative after creating that methane indeed. The moment you burn that methane in your rocket though, it results in that same amount CO2 again. So the best you can aim for is carbon neutral, just like a hydrogen rocket.

    Anyway, at the current flight rate that is not relevant and when it does become relevant in the future, both methane and hydrogen would have carbon neutral pathways.
    With sufficient thrust, water towers fly just fine.

  8. #278
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    Quote Originally Posted by Nicolas View Post
    If you make methane from hydrogen and CO2 rather than using fossil methane, and both the hydrogen creation and methane creation were carbon neutral, you would be carbon negative after creating that methane indeed. The moment you burn that methane in your rocket though, it results in that same amount CO2 again. So the best you can aim for is carbon neutral, just like a hydrogen rocket.

    Anyway, at the current flight rate that is not relevant and when it does become relevant in the future, both methane and hydrogen would have carbon neutral pathways.
    Rockets expend part of their propellants outside the atmosphere...those on GTO or interplanetary transfer trajectories can do so well outside the atmosphere. It's a small fraction of the whole, but rockets powered by methane produced by capturing CO2 would be somewhat carbon negative.

    Hydrogen of course could never be better than carbon neutral.

  9. #279
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    There is an Xprize competition for carbon capturing to reduce atmospheric CO2. I don't know whether throwing that CO2 off the planet altogether is eligible as a proposal.
    With sufficient thrust, water towers fly just fine.

  10. #280
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    Elements of the Artemis Lander system later re-used?

    'The humans of tomorrow will live on Mars' https://www.swissinfo.ch/eng/busines...-mars/46510518
    If we assume that Elon Musk's spacecraft will be available, a human landing on Mars will involve less uncertainty than for a robotic mission, because there will be people and fuel reserves on board. Humans will be able to intervene in the event of unforeseen difficulties and the reserves will make it possible to extend the flight. The landing site for this first mission will naturally have to be chosen very carefully.

    The colony? Technocracy, the government or control of society or industry by an elite of technical experts, the decision-maker or makers are elected by the population or appointed on the basis of their expertise in given areas of responsibility, particularly with regard to scientific or technical knowledge. https://twitter.com/elonmusk/status/...202688?lang=en . 'Accelerating Starship development to build the Martian Technocracy' or another Mars option Martial law, Literally? or the Technocracy would still fall under US jurisdiction; colonial laws and it's corporate law, a US company discovering/colonizing a planet?

    Chairwoman Eddie Bernice Johnson (D-TX) made the following statement.

    “I am disappointed that the Acting NASA leadership decided to make such a consequential award prior to the arrival of a new permanent NASA Administrator and Deputy Administrator. The decision to make the award today also comes despite the obvious need for a re-baselining of NASA’s lunar exploration program, which has no realistic chance of returning U.S. astronauts to the Moon by 2024. While work continues on the upcoming Artemis-1 mission, it will be critically important for the new NASA leadership team to carry out its own review of all elements of NASA’s Moon-Mars initiative to ensure that this major national undertaking is put on a sound footing.”
    http://spaceref.com/news/viewpr.html?pid=57284

    NASA Picks SpaceX to Land Next Americans on Moon

    The agency's powerful Space Launch System rocket will launch four astronauts aboard the Orion spacecraft for their multi-day journey to lunar orbit. There, two crew members will transfer to the SpaceX human landing system (HLS) for the final leg of their journey to the surface of the Moon. After approximately a week exploring the surface, they will board the lander for their short trip back to orbit where they will return to Orion and their colleagues before heading back to Earth.

    The firm-fixed price, milestone-based contract total award value is $2.89 billion.
    http://spaceref.biz/company/nasa-pic...s-on-moon.html
    "With this award, NASA and our partners will complete the first crewed demonstration mission to the surface of the Moon in the 21st century as the agency takes a step forward for women's equality and long-term deep space exploration," said Kathy Lueders, NASA's associate administrator for Human Explorations and Operations Mission Directorate. "This critical step puts humanity on a path to sustainable lunar exploration and keeps our eyes on missions farther into the solar system, including Mars."

    SpaceX has been working closely with NASA experts during the HLS base period of performance to inform its lander design and ensure it meets NASA's performance requirements and human spaceflight standards. A key tenet for safe systems, these agreed-upon standards range from areas of engineering, safety, health, and medical technical areas.

    "This is an exciting time for NASA and especially the Artemis team," said Lisa Watson-Morgan, program manager for HLS at NASA's Marshall Space Flight Center in Huntsville, Alabama. "During the Apollo program, we proved that it is possible to do the seemingly impossible: land humans on the Moon. By taking a collaborative approach in working with industry while leveraging NASA's proven technical expertise and capabilities, we will return American astronauts to the Moon's surface once again, this time to explore new areas for longer periods of time."

  11. #281
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    "Report: NASA Artemis Moon Landing in 2024 – “Highly Unlikely”"

    https://www.leonarddavid.com/report-...ghly-unlikely/

    A NASA Office of Inspector General report has taken a look at the space agency’s Artemis program, noting that the effort faces significant challenges.

    The NASA OIG report explains that current plans to launch Artemis I in 2021 and ultimately land astronauts on the Moon by the end of 2024 are “highly unlikely.”
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  12. #282
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    I'll need to hold some old spark plug wires if I want to feel shocked...
    With sufficient thrust, water towers fly just fine.

  13. #283
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    Yes, it was pretty unlikely timing when they first proposed it. Now, if it had been a “cost is no object” national priority, basically repeating Apollo with as simple a lander as they could manage, and doing whatever was needed to get SLS going in a timely manner, then they could have done 2024.

    But now, it simply isn’t news. It’s been discussed regularly.

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  14. #284
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    The other side of that, though, is that there really could be a landing later in the decade. There’s more real work being done on it now than any other time since the Apollo landings. Even that ridiculously expensive SLS is real hardware. It can’t be used for a sustainable program, but it would work, eventually.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  15. #285
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    Quote Originally Posted by Van Rijn View Post
    The other side of that, though, is that there really could be a landing later in the decade. There’s more real work being done on it now than any other time since the Apollo landings. Even that ridiculously expensive SLS is real hardware. It can’t be used for a sustainable program, but it would work, eventually.
    Yeah there's enough hardware either ready or in development for a landing to be carried before 2028,and I think they will feel compelled to justify SLS with at least one landing before other heavy lift hardware replaces it.

  16. #286
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    A good analysis of the NASA Human Lander System (HLS) Source Selection Statement (why they chose Starship)...

    https://youtu.be/krM8YnlEz_k

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