SpaceX Tuesday...
Discussion
Clive Milk said:
Space X will never get anyone to Mars, their approach of test and fail is not suited to an entire Mars round trip due to the length of time to get there.
If we compare a trip to Mars for a new venture now, we can compare it to the trips to the Moon back in the day when starting off
https://en.wikipedia.org/wiki/List_of_missions_to_...
Note the number of failures. And the moon is just a small step away compared to Mars.
We have a few Mars missions at the moment ongoing, just unmanned ones and still the originators hold their breath in the last few moments. Sure, the tech is getting better, but Mars landings are spotty at best on being successful. Once you are down, looking good. It's getting down that is hard.
How do SpaceX, if they get their vehicle into space and orbit and then go out of LEO perhaps to the moon, get to Mars, and then land and fail, land and fail, take off and fail, take off and fail?The only way they can do that in a timeline is by having multiple rockets en route; but how can you then correct if some major flaw ? You can't.
This is the achilles heal of SpaceX for going to Mars, they have completely the wrong approach. Their approach is test and fail, which is great for LEO and has worked and they have a great system now with Falcon rockets ! Mars is a completely different kettle of fish. It's just too far for this approach to work unless you have an unlimited supply of cash and willpower.
Err they are well on the way to having an unlimited supply of money and will power.If we compare a trip to Mars for a new venture now, we can compare it to the trips to the Moon back in the day when starting off
https://en.wikipedia.org/wiki/List_of_missions_to_...
Note the number of failures. And the moon is just a small step away compared to Mars.
We have a few Mars missions at the moment ongoing, just unmanned ones and still the originators hold their breath in the last few moments. Sure, the tech is getting better, but Mars landings are spotty at best on being successful. Once you are down, looking good. It's getting down that is hard.
How do SpaceX, if they get their vehicle into space and orbit and then go out of LEO perhaps to the moon, get to Mars, and then land and fail, land and fail, take off and fail, take off and fail?The only way they can do that in a timeline is by having multiple rockets en route; but how can you then correct if some major flaw ? You can't.
This is the achilles heal of SpaceX for going to Mars, they have completely the wrong approach. Their approach is test and fail, which is great for LEO and has worked and they have a great system now with Falcon rockets ! Mars is a completely different kettle of fish. It's just too far for this approach to work unless you have an unlimited supply of cash and willpower.
Tesla is worth in the region of $700 billion, this is based on the expectation that it will make more than 10 million cars a year before the end of the decade. To achieve this it would merely have to retain most of it's market share in the EV space, however as a risk adjusted discounted cash flow that would barely justify the current valuation. The X-factor is automation where Tesla are by far the leader in real world data. Should they get this system to work I suspect that they will both run their own robot taxi fleet and also licence their technology. For arguments sake lets say by 2030 ish Tesla licence their full self drive system to 80% of new cars (80 million) for $1000 per car. That would be $80 billion in revenue and would be exceptionally high margin, this is ontop of the profit from 10-20 million car sales and a robo taxi fleet.
That is before we consider that SpaceX is on the path to becoming the ISP for ~5-10% of the global population. That's before we start looking at space data centres and using Starlink's laser links as a new backbone of the the internet.
It is therefore quite feasible that Elon may have dividend incomes in the 10's of billions by the 2030's. That is plenty of money to run one's own space program!
Even if we assume Elon Musk's company's gained little additional value he could liquidate $10 billion a year for 20 years.
How do I suspect he will do this:
1: They aren't going to replicate the blowing things up stage at Mars, spiral development gets more rigorous as you iterate.
2: They will however use a brute force method so no single vehicle/payload is critical.
3: They will end up doing things with people a lot more carefully and are likely to include lots of design compromises
Blocker for getting a Starship to mars is likely rapid re-use of the booster to allow in orbit refuel. Once this is achieved I would expect that by the time this is achieved we are at hundreds of landings for Starships including on the moon.
The initial Mars fleet will be say 10 or more unmanned Starships (brute force) which each carry around 100 tonnes of cargo. This will be a payload of rovers, probes and also the fuel plant and other ISRU facilities e.g. autonomous diggers. The payloads will trade mass for cost and reliability
Before they are ready to send astronauts there will be a buried habitat which has demonstrated months of successful service, landing pads, solar farms and enough fuel to return home. There will also be enough supplies to maintain the initial crew for 2-4 years just in case they can't return. The flight of the cargo ships will validate the life support systems as will a manned mission of mars duration around the moon or just high earth orbit.
The initial manned mission will come 2 years later again most likely it will be massively over specced because St Elon has billions to spend every year and the vessels cost hundreds of millions. Say first mission might be 100 people on 10 Starships (10 per craft). They have so much mass margin I would expect that they could essentially give each astronaut an ejectable pod with a heat shield and retro rocket landing system.
The mass capacity of the Starship essentially allows you to brute force every safety issue. E.g.
LIfe support systems fail:bring 10 ships each capable of supporting all the first mission crews.
Mars landings have low levels of demonstrated reliability: Multiple vehicles mean the loss of any given vehicle doesn't affect mission success. Ejection systems for all astronauts.
Return flight not validated Conduct unmanned flight returns, enable to crew at the base to survive multiple synods on Mars, even with ISS levels of recycling it only takes 1 tonne of supplies per astronaut year and Mars has more easily accessible resources.
I think Elon Musk is simply going to accumulate enough resources that a long term Mars base will happen irrespective of government support in fact there is a very real chance that government support would actually slow it down.
I do however think that a Mars colony that is self sustaining is a very long way away. While I'm sure that hundreds of volunteers can be found to live on Mars and Elon will have enough resources to sustain a pretty large base indefinitely I think it will take a very long time for it to scale up.
Living on Mars will be a very odd lifestyle choice, you are away from earth for years as a minimum you can't have a real time conversation with anyone on earth and it's not apparent what a Martian colony will do for money.
The moon on the other hand is 3 days away has real time communication and there would likely be a very large potential market for tourism once the cost is below even a million dollars per person.
Beati Dogu said:
I think it's pretty clear that Elon and therefore SpaceX aren't that bothered about the Moon. Sure they'll take the US government & private contracts for launch and resupply work, but they're too fixated on Mars to bother with anything of their own on the Moon.
Of course if Starship does fulfill the hype, it'll open up all sorts of potential new projects.
Elon has started to move to a position that Starship will take people to the moon before Mars.Of course if Starship does fulfill the hype, it'll open up all sorts of potential new projects.
The moon is a place to demonstrate most of Starship's functions in a place where you have real time communication and get paid for doing so.
It's also only about 3-4 days to get there and you can go whenever you want. A an optimum transfer window to Mars is about every 2 years and takes 6 months to get there. Given their approach of iterative design and testing to fail, they'd surely be daft not to go to the moon, especially as you say, they're likely to get paid a lot more for it.
Although presumably if starship can get 100 tonnes to mars on a Hohmann transfer, they could carry 100 tonnes extra fuel instead to do a faster transfer if they just want to prove they can get there.
Although presumably if starship can get 100 tonnes to mars on a Hohmann transfer, they could carry 100 tonnes extra fuel instead to do a faster transfer if they just want to prove they can get there.
RizzoTheRat said:
It's also only about 3-4 days to get there and you can go whenever you want. A an optimum transfer window to Mars is about every 2 years and takes 6 months to get there. Given their approach of iterative design and testing to fail, they'd surely be daft not to go to the moon, especially as you say, they're likely to get paid a lot more for it.
Although presumably if starship can get 100 tonnes to mars on a Hohmann transfer, they could carry 100 tonnes extra fuel instead to do a faster transfer if they just want to prove they can get there.
I suppose it would be useful for certain types of practise (low-gravity, bad surface propulsive landings, for example).Although presumably if starship can get 100 tonnes to mars on a Hohmann transfer, they could carry 100 tonnes extra fuel instead to do a faster transfer if they just want to prove they can get there.
Moon just isn't Elon's objective though. It'll only be a destination if it gets him to Mars faster.
RizzoTheRat said:
A an optimum transfer window to Mars is about every 2 years and takes 6 months to get there.
If you're only sending test flights and cargo the flight duration isn't really important, so you can launch using less optimum transfer orbits - especially if you have deltaV to spareThankyou4calling said:
MiniMan64 said:
Space X and NASA might disagree with you there
Loads will disagree with me. It’s just my opinion. We’ve been there.
There wasn’t much to see so it seems pointless to go again.
Other than adventure (which in itself is a fantastic reason) what would be the point?
If not now when?
We have the technology to make going to the moon part of the human experience for a significant portion of the people alive today. Why shouldn't we do this now?
Just to elaborate, in the next 20 years we should be able to get someone into orbit for around about $10-20k. Thus going to the moon is likely a once in a lifetime experience most people could afford.
Initial trips funded by NASA or billionaires are just the down payment that gets regular spaceflight over the line.
Just for reference NASA worked out that it could get 83 people on a space shuttle if they really wanted to (pod in payload bay). So even with that economically disastrous design it was possible to get people into orbit for somewhere between $5-10 million just by scaling up.
Question for the more intelligent than me. One of Musk's stated aims is "make humanity multi planetary". Basically an insurance policy for if the Earth was hit by an asteroid or something.
Would a moon base provide a sufficient insurance policy? Should the worst happen and Earth did end up nuked, would the moon be distant enough to be unaffected? Granted an event as large as the one that caused the Earth-Moon system would be an issue, but then you are going from unlikely to incredibly unlikely?
I can see the logic that Mars has more gravity so is going to be more likely not to cause strange growth defects in humans, however, anyone living on the moon can pop back to Earth easily (while Earth is there).
In many respects it does seem like an easier option to just go to the Moon, if the only goal is to have lots of people living somewhere other than the Earth.
Is there a special reason to prefer Mars?
Would a moon base provide a sufficient insurance policy? Should the worst happen and Earth did end up nuked, would the moon be distant enough to be unaffected? Granted an event as large as the one that caused the Earth-Moon system would be an issue, but then you are going from unlikely to incredibly unlikely?
I can see the logic that Mars has more gravity so is going to be more likely not to cause strange growth defects in humans, however, anyone living on the moon can pop back to Earth easily (while Earth is there).
In many respects it does seem like an easier option to just go to the Moon, if the only goal is to have lots of people living somewhere other than the Earth.
Is there a special reason to prefer Mars?
Flooble said:
Question for the more intelligent than me. One of Musk's stated aims is "make humanity multi planetary". Basically an insurance policy for if the Earth was hit by an asteroid or something.
Would a moon base provide a sufficient insurance policy? Should the worst happen and Earth did end up nuked, would the moon be distant enough to be unaffected? Granted an event as large as the one that caused the Earth-Moon system would be an issue, but then you are going from unlikely to incredibly unlikely?
I can see the logic that Mars has more gravity so is going to be more likely not to cause strange growth defects in humans, however, anyone living on the moon can pop back to Earth easily (while Earth is there).
In many respects it does seem like an easier option to just go to the Moon, if the only goal is to have lots of people living somewhere other than the Earth.
Is there a special reason to prefer Mars?
Basically, Mars has more resources, is bigger, has an atmosphere, a similar length of day to the Earth and is overall better suited to scale up to a self sustaining civilisation.Would a moon base provide a sufficient insurance policy? Should the worst happen and Earth did end up nuked, would the moon be distant enough to be unaffected? Granted an event as large as the one that caused the Earth-Moon system would be an issue, but then you are going from unlikely to incredibly unlikely?
I can see the logic that Mars has more gravity so is going to be more likely not to cause strange growth defects in humans, however, anyone living on the moon can pop back to Earth easily (while Earth is there).
In many respects it does seem like an easier option to just go to the Moon, if the only goal is to have lots of people living somewhere other than the Earth.
Is there a special reason to prefer Mars?
https://youtu.be/H7Uyfqi_TE8
From about 4 minutes in.
Flooble said:
CraigyMc said:
I like this form of explainer; https://www.explainxkcd.com/wiki/index.php/681:_Gr...
That is excellent - really shows the difference between LEO and Geostationary orbits, or escape velocity itself.Does anyone have a cost for a Starship? Probably impossible to calculate, but as I noted earlier, if it's cheap enough to send 20 Starships to Mars for the price of one SLS launch, you can have a lot of practice at every Synod.
For reference a Dragon Capsule costs tens of millions, and a Falcon 9 booster has a manufacturing cost of around $20-30 million. One of the "radical" improvements SpaceX made in the early days of the Falcon 9 program was to bench mark the costs of the rocket against a commercial airliner. Which makes very good sense as they are built out of the same materials and processes.
It probably make sense to do the same with a Starship in which case it would cost between $1 and 2 million dollars per tonne of dry mass. Given that the target mass for the Starship is around 100 tonnes that would equate to $100-200 million.
Einion Yrth said:
RizzoTheRat said:
It's also only about 3-4 days to get there and you can go whenever you want.
Depends on the latitude of your launch site, and available delta V, as you well know plane changes are expensive. Re delta V and plane changes, I doubt they would, but as a private venture I guess they could launch from sites other than NASA's launch facilities. ESA's site is about 5 degrees north, which means you put something like 5% more payload in to orbit for the same launch vehicle, and every 12 hours could launch pretty much in to the plane of the moon which saves a load more fuel too. Of course transporting a rocket there would be a hassle but once you have something that's capable of suborbital flight and powered landings anything becomes possible.
rxe said:
Agreed. Mars has enough atmosphere to burn you up, but not enough atmosphere to make flight controls easy. They may need bigger “wings” on the Starship for example. But the underlying physics is the same - you scrub off some speed in the atmosphere, and you scrub off some with rockets. Mars will be more rocket than Earth - I wonder if they’ll do a long burn before they even enter the atmosphere to get the speed down to something sensible.
I don’t see how they will be able to land safely on an unprepared surface, maybe they’ll land a load of unmanned ships to get supplies down, and then land humans in a more conventional disposable capsule. The humans then get the concrete mixer out.
You won't do a burn before hitting the atmosphere because there is no way you could carry enough propellant to make much of a difference.I don’t see how they will be able to land safely on an unprepared surface, maybe they’ll land a load of unmanned ships to get supplies down, and then land humans in a more conventional disposable capsule. The humans then get the concrete mixer out.
The Starship belly flop is around about 80-100m/s on earth, Mars atmosphere is more like 1% of that of earth which would equate to about 700m/s on Mars. However that velocity is super sonic which would increase drag. Thus actual terminal velocity is more like 340m/s.
This will need more fuel to slow down in but the difference isn't quite a great as you may think as the gravity drag is lower on mars. e.g. a space craft slowing at 1.5g on earth slows at 2.2g on Mars for the same thrust.
Regarding safety there are a few solutions I can see:
1: Escape capsules, for a human mass object most likely sensible method is a parachute and airbags. Given the issues with the Starship flip some sort of Zero-Zero ejector seat would be needed to get the paracute and airbag up to a deployment altitude. Alternatively a
2: Pre-prepared landing zone, I think the idea will be that the human carrying craft will arrive to a relatively infra structure rich environment.
3: Mutual support, its likely that you would want the space craft to be spaced a decent distance apart on landing but wait for the astronauts is likely to be a fully pressurized electric rover. Ergo if anyone ejects they will assisted by their colleagues from another craft in a time-span of minutes.
4: Under carriage: I bet by the time we get a martian landing the starship will have some sort of wide track spider like undercarriage.
Edited by Talksteer on Tuesday 2nd March 15:24
"SpaceX has concluded fatigue on an engine cover caused one of the nine Merlin 1D first stage engines on the company’s most recent launch to shut down early during ascent, leading to the loss of the booster during an offshore landing attempt in the Atlantic Ocean, an official said Monday."
https://spaceflightnow.com/2021/03/01/component-fa...
https://spaceflightnow.com/2021/03/01/component-fa...
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