Rocketry General Thread

#1045

Yeah I think the manned surface missions are a little too ambitious this early in space development. Maybe orbital missions at the most, just to have a human presence and to test human capabilities for a Mars mission. I would much prefer to see a whole bunch of machine-constructed support infrastructure at the moon and mars first so that humans have some sort of life line available when we eventually reach that point.

#1046

Just like booster core recovery five years ago…

Landing on Mars really isn’t so bad if they get the BFR working. Getting the BFR working at all will be the main difficulty. Once it’s up, Mars is easily in the picture. They might burn up a few upper stages in the process, but I have confidence that they’ll get it right if they get the BFR right, which I am fairly confident in as well.

#1047

??? Zen I have no idea what you are talking about.

They’re basically equavilent ± a few hundred deltaV. Aerobreaking reduces the entire circularilization and landing delta V costs to a few km/s. Lunar surface costs about 5.5 km/s and so does the Martian surface(due to saving roughly 3km/s aerobraking) assuming optimal launch windows and hohmann transfers. I may be wrong as well with that because I have no idea to what extent they can shed velocity in the Martian atmosphere. It’s thin but multiple km/s will generate a lot of drag either way due to the fact drag scales as velocity^2.

We know that this will not be the case due to BFR taking an accelerated route costing more dV for a lower travel time, but for cargo launches this can be done.

Also, citing his presentation, BFR would have be refueled to land on the Moon This would happen in a largely elliptical orbit around Earth right before inserting and circularizing around the Moon. This is because there is no way for BFR to refine its own fuel on the Moon and some of its 150 ton payload will absolutely be reduced because it has to land its fuel to get back to Earth, rather than making it on the surface.

#1048

I think that going back to the Moon first will be the safest manned steps to take. So the companies/nations can re-learn manned planetary bodies landing, with the relative safety net of only being a few days away from Earth if a rescue mission was required. Even better still, if there was a craft waiting docked to the ISS that could go with very short notice.

Practising on the Moon with some basic habitats, and that idea of moving surface Lunar soil layers up and onto tough dome habitats. Something that will need to be practised a lot first before trying on Mars.

I think the other idea has merits as well, having craft turned into boring machines that dig into the sides of a small soft crater, sealing itself from the rear as it goes creating a pressurised heated habitat linked to large fields of solar panels also being laid down by other robotic landers. and with subsurface ice water nearby as well.

Which ever method gets the go ahead, maybe both. Will need some serious R&D and the Moon seems close enough to fix mistakes and upgrade equipment in fairly fast cycles.

The Moon as training wheels and staging bases for the push to Mars. Spacex, ESA, Nasa and the Russians and China.

And all streamed 24/7 to us via websites in 1080p-4K, with multiple cameras to chose from :slight_smile: Although I’m not sure how much the Chinese will allow us to see of their missions with regards to live streams. Spacex and Nasa and ESA will though.

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#1049

This is the kind of discussion I was hoping for. I think you have a lot of valid points but I think we need to research the differences in environments more. Maybe it’s a problem or maybe it’s not but there can be differences between the soil properties and something that works for the moon may not work on mars and vice versa. Does the addition of slight wind erosion effect the abilities of our robotic friends to operate and complete their jobs. Can we use the same machinery for both jobs? If the case is no, they won’t work then we will have to have separate development teams for each environment and it splits the already low amount of resources available.

Although you are right and the processes are the same. Can we not test that on Earth though? If we are already ignoring the differences of separate environments the only differences are low gravity but even Mars and the Moon have different gravities. What’s the cut off for what works and what doesn’t? No clue and I have a feeling we won’t figure out what works until we are actually there whether there is the moon or mars.

Id add more but I’m mobile but I just want to ask what’s the point of practicing on the moon if we can practice the majority of those things with less risk than practicing on the moon. Why add the extra risk and cost? Cool factor is also a valid answer but a risky one because it in a way gave us the shuttle through mission creep.

#1050

I’m slightly disturbed how everyone calls him Elon. The other big example about a public figure called by his first name on his time… well that particular polity did have a pretty spectacular space program not long after, so there’s that.

#1051

A good chunk of that is simply that it’s a distinctive name. If he was “David Musk” you can be sure that everyone would call him “Musk”.

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#1052

It appears that some here are so caught up in the Musk personality cult that they can’t see straight. This is why we are going to the moon before mars and this is why mass transportation by rocket isn’t going to happen in the foreseeable future. Some here are sounding like Chris Roberts zealots and refuse to separate existing technology from fiction. But please go on about how affordable rocket travel will be compared to airlines - it truly is entertaining, especially when the only solution so far for G-forces is ‘slowing’ the rocket down. lol. Anyway, I learned my lesson on RSI forums, you can’t bring logic to the table when everyone is eating BS PR.

#1053

Now those are great questions and worth discussing. As for comparisons not being applicable, no doubt different conditions will require different materials and mechanics. But there is something that gets overlooked: human performance and interaction. Sure we have had astronauts in low orbit for long periods but being so close to earth is one thing, being on the moon is entirely another where just jumping into your capsule during an emergency isn’t going to suffice. Also any base on the moon will emulate what kind of human interaction will take place on mars, especially a multi-nation endeavor. Again we should learn how to walk before we run. Also logistics and protocols will be no small thing and what’s just as important as getting astronauts to the moon and/or mars and back is insuring mission control is organized and competent. No small feat for Nasa given they left America virtually without a space program.

#1054

Zen… what are you actually arguing? That the BFR is ridiculous? Because that’s actually a ridiculous claim.

You’re going to need to actually explain the physics and financials of what’s problematic with the BFR’s suborbital earth transport. What’s unrealistic about his claim, and explain financially or physically why, with estimates on what the cost per launch will be based on the cost of the vehicle and reusability.

Go ahead. You’re implying that you’re somehow smart for being a contrarian with your haughty attitude, so, please… please give me your best analysis.

#1055

At a certain point it’s like talking to flat earthers. “There is no problem having your head in the clouds, as long as your feet are on the ground!”

#1057

Can some girl :blonde_woman: around here help the community, please ?
…then obviously repost it around here :rofl: so we too can have some lols

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#1058

I would but a girl would have to be 5 IQ points from Playbenni which would put her in the negative. :stuck_out_tongue_winking_eye:

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#1059

I’m taking my second semester of quantum mechanics from a woman who probably has an IQ of around 160. Which, also means I’m probably fucked because she’s going to think that hard concepts are easy. So, yeah… fuck that sexist shit.

Anyways…

Thunderf00t is a contrarian, and if you think that he’s in any position to cast that level of shade on the topic, you’re really just not seeing the whole picture.

Do you know what thunderf00t gives people? Do you know why he makes his money? He gives people a sense of superiority. You feel superior to people who are optimistic and excited about spacex.

That’s what he gives you, that’s why you watch his videos. It’s also kind of what drives the completely unnecessary ick factor in the new atheist movement - and is primarily why the movement fails to effect change other than making neckbeardy people who were agnostics into neckbeardy people who are atheists, as if that’s what atheism needs by association.

So… Yeah. I actually calculated the radius of a BFR explosion based on energy, though it’s very rough. It should be 80% of a hiroshima bomb, which is a 1 mile radius. So, 0.8 miles away is about 10 football fields. Plenty of water and land, and you could make it 10 miles away from any structures and you’d be fine.

Furthermore, you could build a shielding system within the spacecraft and on the launchpad so that passengers would survive, after you get the explosion rate down to one in a million.

There are some obstacles to overcome, but it’s really not nearly as far fetched as thunderf00t would have you believe. Don’t believe that contrarian crap - think critically, do the math yourself - and if you don’t know the math, learn some of it at least. Try to look at it from more angles than just the contrarian one.

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#1060

You’re absolutely right. Playbenni would be in the negative while ‘the ladies’ would be in the positive. :grin:

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#1061

Nasa did the math. Doesn’t work. Unless of course Nasa is filled with ‘contrarians’.

#1064

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#1065

Sorry, my comment was kind of mean and I didn’t mean to drag the conversation to this level. I’m going to stop here, at least in the context of this conversation and keep it to a less debate tone, because we are all far too uneducated to really debate the topic. This should be more of a dreaming thread, if anything.

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#1066

No worries. I will respond in kind. :vulcan_salute:

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#1067

Good to see things have sorted themselves out :slight_smile:

Aaaand another SpaceX satellite launch tomorrow :blush:
https://spaceflightnow.com/launch-schedule/

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