Astronomy and space exploration

Discussion in 'General Discussion' started by eloyc, Apr 10, 2017.

  1. Grall

    Grall Invisible Member
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    Yeah well maybe so, but it's still awesome to this overgrown nine-year-old's mind! :D

    Btw awesome youtube vid of the landings:



    SIX sonic booms, hell yeah! :D And a mighty roar of the rocket engines too, damn! Beautiful, just beautiful. Well, except for all the wildlife we just scared the crap out of I suppose, lol... But, they'll settle down again eventually. Gotta break some eggs, yes? :p
     
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  2. zed

    zed
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    OK thanks, my point still stands, trying to land on a barge in the ocean is not smart
    Yes I assume its that and also political (though space x is non governmental so in theory this should make no difference)
    I don't see why theres any reason that can't do like here in nz with its spaceport (out in a field) most of the business is run elsewhere, be it america or whereever but the launch happens in nz.
    Like I said Near broome is one of the largest Port's in the world, so they obviously have the facilities to deal with shipping the rocket from the US to Australia, another point in favour of Oz is theres a lot less air traffic

    https://www.hq.nasa.gov/pao/History/SP-4204/ch1-2.html
    That is a shitton less payload being able to be delivered, whilst I can understand it for the saturn V being from the US government they want it on US soil, and cost ain't so important. But for a private company I'm guessing this is a huge handicap
     
  3. zed

    zed
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    #143 zed, Feb 7, 2018
    Last edited: Feb 7, 2018
  4. Grall

    Grall Invisible Member
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    Well, if you have contracts with the U.S. air force to launch super-secret spy satellites, a certain amount of gov't paranoia says that you probably don't want to stick your top of the line military hardware (which is super-secret, remember) on either a freight ship or an air transport and haul it halfway around the world to a foreign country, and then launch it into space from said foreign country... Not when you could launch it all from within Merica itself.

    Plus, staffing. A company of this sort lives and dies with the staff you can hire. You can't take on McDonald's burger flippers to pad out the warm bodies count; just about every position requires specialized training of some sort, and all of the research and design work, programming and so on very very much so. Plus, inter-relations chemistry and all that.
     
  5. 3dilettante

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    SpaceX is a company headquartered in the US, and the US is a critical customer that will inject political considerations regardless. The US also hosts a significant amount of the infrastructure.

    Probably going to involve flying over the ocean if NZ is the launch point. The barge provides more operational flexibility for launches with recovery, since the amount of fuel held in reserve can be reduced.
    Other launch centers have over-water corridors as well, so those could use a barge if they adopted the same scheme.

    Some of that math looks to be specific to the Apollo mission profile, and other parts are more important to a subset of orbits.
    Not every launch needs an equatorial low-earth orbit, and missions without the limited endurance of a manned mission to the Moon can have other options for orbital changes that can take weeks/months to complete with the upside of expending less propellant.
    The figures I've seen quoted generally trend towards the lower figure, and existing equatorial facilities can supply that part of the market. Many satellites also fall short of max mass budget, since mass costs money.

    There are some measures taken for the landing struts and for the ship that can try to mitigate some amount of swell, though the chance of asymmetrical forces or an unexpectedly further drop to the deck overwhelming one or more struts and causing damage or failure would exist.
    Tipping, if the rocket is itself mostly level, is less likely. The vast majority of the stage's mass is in the machinery and engines in the base. The rest of the stage is a mostly empty set of chambers that have been engineered to be as light as feasible.

    edit: fixed spelling
     
    #145 3dilettante, Feb 7, 2018
    Last edited: Feb 7, 2018
  6. Grall

    Grall Invisible Member
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    Would it really matter if you do a moonshot from an equatorial orbit or not? I mean, even if you launch straight south from cape canaveral and aim at the moon coming from a polar orbit, you'll end up at the moon... :p Is the speed you can leech from the Earth's rotation really a meaningful amount in such a situation...?

    Furthermore, I'm thinking you could surely even end up in a moon-equatorial orbit (so you can more easily land at your desired landing site) with a very small change in vector here at earth, considering the vast distance you have to traverse to get to the destination... Oh well. Just speculating. :p
     
  7. 3dilettante

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    To correct my initial reading of the passage on the Saturn (overall launch vehicle, not just Lunar program) launch site, other references indicate that it's less important for an actual moonshot since the Moon's inclination and the Earth's axial tilt means it doesn't orbit around the equator. There are weather and communications satellites that would consider this more important.

    The energy cost of changing orbital plane for them is where the larger figures of mass penalty show up for Florida.

    Lining up with the Moon likely balanced a number of factors, although the biggest was apparently allowing for the chance of returning even if the service engine failed.
    https://www.hq.nasa.gov/pao/History/SP-4214/ch6-2.html

     
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  8. cheapchips

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    I respectfully disagree with you sir! None of their ocean failures have been due to sea conditions. They've recovered 12 boosters that way with fairly minimal costs. It's not dumb at all.

    It's worth noting that some of the failures at sea have been them just having a crack at landing something with the barest of fuel/heat margins, because why not try. They'd have failed a land landing too.

    If you think landing on a massive barge held in position by oil rig stabilisers is dumb, you'll love what Blue are planning for New Glenn. They're landing downrange on a moving tanker. :)

    At the Cape and Vandenberg Space X were able to adapt existing launch pads, saving $100m's in infrastructure costs. All the range support need is already in place as well. The economics and practicalities of launching from elsewhere aren't worth it for a bit of extra margin. Might as well go disposable or reusable FH.
     
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  9. Davros

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    Oh, just you watch them ;)
     
  10. zed

    zed
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    Perhaps not, but I do find it telling that all the landing failures so far have been trying to land on the ship, where every landing on the ground attempted has succeeded

    S= Success F = failure
    Ship FFFFSSSFSSSSSSSSSF
    Land SSSSSSSSSSS

    Its logically going to be harder, Smaller area, platform moving up and down in the swell, much faster wind ( double the wind speed = 8x the wind force)
    Also I dont know but I'm thinking all that sea water over the rocket means it needs a good clean afterwards before its reused :D

    The margin of fewer crashes may only be a few % points, but you've gotten also factor in the extra payload you'll be able to launch.

    Sure if they were only planning to go to space a few times its prolly not worthwhile looking at a better place than Florida but Space X are looking to go to mars, they're gonna have to do a shitton of launches
     
  11. itsmydamnation

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    that is because you are ignoring key parts of the equation.

    They land at sea because the don't have the fuel to make it to land. Generally this is because of the target orbit, these orbits result in higher re entry speeds with less fuel to slow the decent.

    If you think what they are landing in is bad conditions you need to see what the average navy chopper pilot has to deal with and they also have to deal with the effects of the superstructure of the ship.

    With the failures that have made it to the drone ship, all of them have hit the mark, but they have had other failures. Just like the latest one it's failure had nothing to do with the ship, it was engine ignition.
     
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  12. Grall

    Grall Invisible Member
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    It'll need a good clean regardless because the lower part of the rocket is all covered with sooty engine exhaust from the in-atmosphere deceleration burns. Also, as the barge is a rather wide craft, ocean swell would need to be extremely strong to rock it to any substantial degree, and they'd never bother trying to land under such conditions anyway.
     
  13. zed

    zed
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    Bingo, ideally they don't want to land at sea yet they are forced to because of the poor choice of choosing Florida(*) and thats why it's better to choose a place where they can land on the land like Australia

    I dont know if you're aware of this but Nasa's control center is in Houston, not in florida (where its launched from).
    check out NZ's space program http://rocketlabusa.com/careers/positions/
    you will see 90+% of the jobs are in auckland (rocket built), 1 job in mahia (where it launches from), 1 in Los Angeles (headquarters) i.e. only a small percentage of ppl work at the launch site (broome's a Nice place as well)

    What I'm suggesting is something similar, The space X rockets can be built/controlled from the USA. Its just then they are shipped out to eg Australia for a far better launch site, theres no need to move everyone to Australia.
    Just read one of Space X's rockets failed due to high humidity (water freezes in the coldness of space), remember space shuttle challenge (ice), both these issues are non existent in Australia.

    The only pro argument I see for staying at florida is 'The infrastructure is there already' all other pro's are in the 'move the launch place camp'

    True it will need to be thoroughly cleaned, anyway. About the second part of your statement take a look at the last video I posted (first 30 seconds or so) seems to be tilting ~5 degree's Sure it made it perhaps it can handle 10 degree's whatever but its certainly not as easy as a 0 degree tilt

    (*)I could understand it during the cold war, you want to have it part of the continent USA and it being a government organization etc, but this is 2018 and its a private organization
     
  14. 3dilettante

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    This seems to also point to the most failures being near the start of the learning curve for landing in general. Without a barge, the whole Ship category would simply be lost boosters.
    It's also something of a two-for-one, as being good enough to land on a barge means being good enough to land on a land platform.

    At least one of the ship failures was a landing SpaceX knew was a probable failure, as the fuel reserve from the launch was below safety margins. The cities and launch centers on land appreciate not having that kind of boundary pushed. The level of experimentation is likely higher because the stakes for such attempts are much lower over water, where spent stages are traditionally expected to land in.

    Impact with salt water and immersion, sure. A ship means some salt spray and external dripping that isn't going to climb up into the engines or tanks. A booster was quoted as being ~$60 million (edit: Falcon 9 cost, first stage estimated elsewhere at about half that) a few years back, saving it seems like it can go through the car wash at least twice before it becomes unprofitable.

    A booster stage costs tens of millions of dollars, while fuel costs several hundred thousand. It's the outsized cost of the booster and the need to reuse it that underpins the business model of SpaceX.
    At the same time, limiting the rocket only to orbits achievable with its existing land-based pads would cut out all those launches with ship landings.

    That would be up to SpaceX when it gets to the point that it can afford to build its own Mars program (and own space industrial complex?). Getting to that point, and accumulating the necessary technology and resources had to use what was available.
    The BFR appears to be slated for returning to the launch pad, though that is a future plan and wouldn't be possible without the testing and business enabled by the current launch profile.

    Does Australia sport the infrastructure and client list offered by NASA and the US government/military/agencies?
    Even then, there would be incentives, or requirements to keep it on the coast.
    Governments tend to be more controlling of launch trajectories over land, and some cargoes like radioactive power sources can be objected to rather strongly.
    There's also some flexibility for launch track problems over water versus land, depending on how much room there is before the rocket must be destroyed.
    A recent equator-launched Ariane flight was at the threshold of being remotely destroyed, since its over-water track deviated significantly.
    http://spacenews.com/satellites-pla...bits-by-ariane-5-can-be-recovered-owners-say/
    It's potentially the case that even with the safety corridor offered for the over-water route that the rocket may have gone past safety limits. I read stories indicating it may have been so off-course that it might have overflown an inhabited area.

    Even if there's enough mostly uninhabited land, that doesn't remove the utility of proximity to infrastructure, port access, industry, and clients. The outback doesn't quite provide those, but the cities on the coast and their ports do.
    Water recovery also has a nice property of combining landing site flexibility (one barge, many launch trajectories and landing points) and shipping (flexible transportation routes of a 25.6 metric ton explosive and chemical hazard with no train schedules or highway blockages).

    That's a pretty huge one, and even if handled it doesn't rule out using ocean recovery. SpaceX is not capable of funding that level of investment or operating costs on its own, and the US has an established world-class local space industry.

    The US-based organization is using US infrastructure, US contracts, and can carry US satellites. The particulars of the satellites matter as well. If a satellite cannot leave the US, a SpaceX launch pad elsewhere is out of the question.
     
    #154 3dilettante, Feb 9, 2018
    Last edited: Feb 9, 2018
  15. tangey

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    To me, that looks super sci-fi and futuristic. Mostly, my experience has been that it takes a lot longer for sic-fi to become reality, to the point that by the time something actually arrives, it's long past being "wow". But this kinda looks ahead of time, which is awesome.
     
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  16. WhiningKhan

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    Well, my first impressions were flashbacks of 1950's sci-fi rockets. Admittedly / sadly considering the topic, they can still be mostly considered futuristic.[​IMG]
     
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  17. Gubbi

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    Like this ?



    Cheers
     
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  18. cheapchips

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    It's a shame DC-X in the early 90's didn't lead anywhere. The program completed its objectives, VTOL, mock reentry manoeuvring, rapid turn around.

    It could have led to a reusable vehicles if someone wanted to fund it further. Another might have been!

     
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  19. Sxotty

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    Elon's ingenuity is not engineering it is fundraising. You just highlighted how essential that is.
     
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  20. cheapchips

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    Testing reuse development on paid customer flights is definitely part of the picture. It might have cost $1bn to develop reuse, but they didn't have to raise/risk capital to specifically do so.

    It's not just fundraising, it's costs too. He has a clear idea of what's physically possible and pushes his teams on those bounds. Tom Mueller, head of propulsion, suggested that sometimes this is a disaster. :) When it works, the upside is that it leads to things like significant amount of plumbing being stripped out the Merlin engines (cost, performance and reuse improvements). Mueller is a genius propulsion engineer by all accounts, but he clearly credits his boss with pushing where others just wouldn't.
     
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