Moon/Mars - just go !

  • Thread starter drag
  • Start date
  • #26
Nereid
Staff Emeritus
Science Advisor
Gold Member
3,367
2
Originally posted by enigma
Actually, propellants are such a small percentage of the cost, that they can be more or less neglected.

*SNIP

The cost per kilo of LH2 or LOX runs on the order of $1/kg when purchased in bulk quantities.

So, for the first stage of a [...] which has a mass of 26,760kg you can make the approximation that it cost around $1.9 Billion to develop and $144 Million to make the first one. Compare that with around $200,000 for the propellants.
That's around 10kg of propellant per 1kg of first stage.

Materials? Let's assume $10/kg and, being generous, another $10/kg for assembly.

Electronics? Likely but a fraction of the cost of the propellants; $100k tops.

That leaves the complex machinery (rocket engine, pumps), assembly, and overheads; overheads should be able to be brought down to ~<20%.

This toy calculation suggests that enigma is right to focus on getting to 'mass production'; a not unrealistic target per-launch cost of getting to LEO is $100 to $1,000/kg.
 
  • #27
enigma
Staff Emeritus
Science Advisor
Gold Member
1,752
13
You may be interrested in this, Nereid.

It is the lecture notes from a spacecraft design course on vehicle costing.
 
  • #28
2,193
2
Originally posted by russ_watters
Not to worry: no one (not us, not anyone else) is going to colonize the moon or Mars.
Curious. That's a very bold statement! Perhaps you would be willing to share your thoughts on this, as I cannot see how a single individual could ever make such a prediction of future events!
 
  • #29
russ_watters
Mentor
19,791
6,192
Originally posted by pallidin
Curious. That's a very bold statement! Perhaps you would be willing to share your thoughts on this, as I cannot see how a single individual could ever make such a prediction of future events!
Well, save for limiting that statement to my lifetime, I'm sticking to it. Space travel is so fabulously expensive that without a compelling reason to do it, we won't. With the technology likely to be available in the next 50 years, not a whole lot will change as far as the engineering limits on space travel. Even with the volume discount Nereid and Enigma are discussing, even just putting a colony (a colony means a semi-permanent base with at least a couple dozen people) on the moon would requie a substantial fraction of our GDP, indefinitely.

Want another prediction? China won't be putting a man on the moon.
 
  • #30
Nereid
Staff Emeritus
Science Advisor
Gold Member
3,367
2
Originally posted by enigma
You may be interrested in this, Nereid.

It is the lecture notes from a spacecraft design course on vehicle costing.
Thanks.

Seems to me we need some left-field thinking.

Do similar sorts of heuristic formulae apply for other large, complex machines (e.g. large commercial aeroplanes)? How have other industries managed to get the costs of unit production down? Is there anything that gives us a clue as to what the long-term unit cost of production could be (based on some general principles)?
 
  • #31
12
0
Originally posted by drag
I didn't continue the little argument we
had above, because it looks like a general
theoretical and partly even philosophical
discussion that won't lead anywhere. We'll
just have to wait and see.
(Besides, I know I'm right...:wink: )

Why read the article after you see the picture ? :wink:
It tells you ahead what you're about to read.
This has nothing what so ever to do with space exploration
programs and I see no reason to adress any meaning to this
irrelevant "critisizm".

Peace and long life.
Drag, you won't understand much if you draw conclusions based on one picture and are not willing to listen to other people's views.

What Bush is proposing is a farce. We can't go to Mars on a 1% a year incease in the NASA budget and by trying to save some bucks by abandoning the ISS and other research projects.

One of the purposes of the ISS was to learn to live and work in space long term so that we could go to Mars.

What Bush is proposing is short-sighted and unplanned. It suffers from the go-it-alone approach that has plagued the Bush administration from the start. The cost of a single country doing this on its own is staggering. It was difficult to even get the ISS running with the help of other countries.

One has to at least look at what the return is on a human Mars mission compared with the science and research that is going to be lost to pay for it.

The same thing happened it the 60's. It was a great sensational thing to go to the Moon, but many other projects got scrapped in the process. We would likely have single stage to orbit vehicles today if projects like the x-15 in the 60s didn't get scrapped because of the Moon mission.
 
  • #32
enigma
Staff Emeritus
Science Advisor
Gold Member
1,752
13
I agree with pretty much everything you just said, but single stage to orbit is a bad idea. The physics behind them simply don't work out...
 
  • #33
12
0
Yes, SSTO is not easy. Trying to add a significant amount of enthalphy to the gases with an airbreathing engine at hypersonic speeds is tough.

Nonetheless, there was a great deal of progress made during the X-15 program. It would have been great if that project and ones similar to it had been active from the 60s to the present.

The scrapped X33 program is another example of poor planning, They were essentially trying to build a space plane with technology that hadn't yet been proven out. It ended up as a waste of money. It shows what happens in a poorly planned project where the science and research aren't thought out first.
 
Last edited:
  • #34
37
0
To mars

NASA is a space exploration agency not a space construction agency. Whomever decided to begin building ISS did not understand the fundamental purpose of NASA because ISS is draining NASA. Therefore, I say COMMERCIALIZE ISS now. (Yes, commercialize you socialists. The government cannot continue to monopolize outerspace and space travel will not become popular until space is commercialized. Why do you think there is so much excitement about the X-prize? Why do think there is even an X-prize?)

Someone said that man will NEVER leave the solar system. True, with current propulsion, we won't. Voyager has not left the solar system and that was like 30 yrs ago. However, with wormholes and/or warp drive it would be difficult not to leave the solar system.
Current feasible propulsion designs (that I know of) are momentum transfer, inertial force deviation and project ORION. Momentum transfer is when a projectile is fired from a moon-based rail launcher and caught by the ship. The basic principle is conservation of momentum. Inertial force deviation is where there are a bunch of wheels that create a wicked centipetal force. Project Orion is probably the best, but the environmental NAZIS would never allow us to use it. :cry:

Others have expressed doubts about the mission to Mars. These people are defeatists who continually whine about something ...cost...Bush...ISS...BLAH, BLAH, BLAH and before that it was SDI ...bullet hit a bullet...starwars...laser beams... :zzz: . These people don't have a basic grasp on human history and how humans have always risen to a challenge.

After mars, the next horizon is asteriod mining. I am personally anxious to get my hands on some of those exotic ferrites. :biggrin:

I also read somewhere that the moon has some weird compound (Fe23Cr)? from asteriod impacts. :smile:

BTW Russ Watters, there are things today that did NOT behave according to the laws of Physics a century ago. A magnet balancing an object in midair was considered near heresy a while ago; yet, today there is the levitron. All quantum mechanics would defy the laws of physics a century ago, IT DEFIES THEM EVEN TODAY. Objects passing through walls, going faster than the speed of light, parallel universes. WERE YOU BORN IN A BARN?
 
Last edited:
  • #35
drag
Science Advisor
1,062
0
Greetings !
paults2 said:
Drag, you won't understand much if you draw conclusions based on one picture and are not willing to listen to other people's views.

What Bush is proposing is a farce. We can't go to Mars on a 1% a year incease in the NASA budget and by trying to save some bucks by abandoning the ISS and other research projects.
First of all, I'm all for the ISS.
Second, well... what can I say... Just give Burt
Rutan, for example, NASA's budget and he'll have
people on the Moon in a few years, ignoring
for the moment the fact that beyond being a visionary,
an inventor and an engineer, he's also a bussiness man
and there's no short range gain here.

Maybe, some of them won't make it. Maybe it'll be
a lot riskier, but hell, I'd go if I could and so would
others.

NASA acts in a completely different manner,
and it also has much greater responsibilities being
a government organization. A LOT of what they do
could be skipped and filled in later. Many plans
and programs could be changed or cancelled if
the objective was not overall incremental development
of the entire field, but rather a type of garage-style
competative thinking when you use the things
you already got and know. Of course, there's no
reason to act like that if you're just developing
the field and creating new technologies, but when
yuor mission is to go somewhere - actually implement
this stuff, no matter what the reason is, then that's the way you should act.

Take the X-33 program, for example, how many billions
did it cost ? Yeah, they learned many new things
(amongst the fact that it's a bad idea :biggrin:),
but the mission was to build a simpler - cheaper
and safer large surface to orbit reusable transport,
and that mission failed. Why ? Because they tried
to build something based on knowledge and
technologies they didn't have yet. Maybe if
they took much less money and built a simple
orbital freighter with a cargo hold and cheap
multistaged rockets, they would not feel as proud
as they would had they succeeded, but they
would accomplish their mission, greatly increase
practical capabilities in space and save a lot
of money for reseach of the same things they
tried to develop on the X-33, without the risk
associated with their actual implementation before
it's abvious that they'll work.

But, anyway, if the question is merely one of
exploration and development, of course it should
continue in any way possible, and I'm SURE there're
great new possibilities.

Live long and prosper.
 
  • #36
18
0
It is a terrible comentary on the state of our race to see educated people putting such hard limits on such unknown areas.

1. I happen to agree that physical Laws are not to be bended, but look at what you are calling a law. F=ma is a law (Newton's first if I am not mistaken), but E=mc^2 is not a law it is the THEORY of relativity. Why would one put them in the same category. The existance of gravity, and its relationship to mass is a Law, but we have no Law that keeps us from escaping the earths atmosphere.
A. as a side note : there is some doubt as to wether or not the law
of conservation of mass is actually true, but some experiments
with high energy collitions have hinted at matter converting to
energy. (which would make the law of conservation of energy
incorrect as well). There is no conclusive evidence, so I will not
say that it proves or disproves anything, but it dose lead one to
wonder, dose it not?

2. There are absolutly no physical laws that keep us from colonizing any planet we can reach (Moon (which I know isn't a planet, but it is a celestial body so it will work for my example), mars, even pluto if we really wanted to waste those resorses. the big barriors lay in another set of laws and an terribly annoying feild, Economics. The great thing about that feild is that it is not based on anything more than greed, so it is lible to change in the next 50 years (for better or worse I do not know) so it may or may not become more fesable then. Annother feild that is limiting colonization is the Technological feild. I know that a lot of people say that we have the technology to do it right now, but I would not agree with theim whole heartedly. I do beleive that the technologies we lack are not at all outside of our reach.
 
Last edited:
  • #37
37
0
Waste

Waste resources going to other planets? How many resources would we waste by going to Titan (a moon with a natural gas atmosphere and oceans)?

How many resources did we waste by going to the moon? You're life would be vastly different if it were not for the technologies developed in the space program.

F=ma is newton's second law
The first law is an object in motion says in motion and an object at rest remains at rest.

And anyone who has ever watched star trek knows that mass and energy are interchangeable. Regardless of whether the boson is found or not.
 
Last edited:
  • #38
37
0
Rock on Drag

A farce paul? People like you have criticized GWB for everything. Remember a while back GW said that America would give billions of dollars to fight aids in Africa. Did he? YES. Remember when GW said he would enforce the UN resolutions on Iraq? Did he? YES. The point is that GW does what he says and says what he means. What a difference from BC who said a lot, but did ABSOLUTELY NOTHING. I remember after terrorists attacked us in Mog, Somalia he said something like don't worry we are going to get these guys. Yet HE DID NOTHING. In fact he always said I am working harder on <fill in the blank> then I have ever done in my life. Yet he did nothing and look at where we are now.
 
  • #39
18
0
First of all I was saying that pluto was probably a bad choice of planets to visit. the resorses were not and would not be wasted on a moon mission, and they would also not be wasted on a mars mission. (secondly Titan is a very interesting topic. First of all the oceans are theorized to be made up of methel-ethane, which is not exactly natural gass, but it would still be a valuable resourse. However, I must also stress that it has not been proven. the atmosphere is so thick that the only reason that they beleive there to be oceans is because of large discolorations in the photos taken by one of our probes as it passed by. the Cassini probe has been launched and will be arriving in this very summer, and it's purpos, among other things, is to determine if there are oceans and what they are made of if they do exist. you can learn more about that at the NASA website.)

Thank you for correction my mis-quote of the order of newtons laws, I didn't have a refferance with me at the time.

I realize that Sci-Fi shows use a lot of real science to intigrate into there entertaining and stimulating plots, but they do tend to exadurate from time to time, or say things as fact that is now only theory. And I stress theory!! that means that it can be proven wrong still. we as men and women of science mus always keep an open mind to what the universe will through us next.
 
  • #40
russ_watters
Mentor
19,791
6,192
Allah said:
BTW Russ Watters, there are things today that did NOT behave according to the laws of Physics a century ago. A magnet balancing an object in midair was considered near heresy a while ago; yet, today there is the levitron. All quantum mechanics would defy the laws of physics a century ago, IT DEFIES THEM EVEN TODAY. Objects passing through walls, going faster than the speed of light, parallel universes. WERE YOU BORN IN A BARN?
Could you be more specific? A magnet balancing an object in midair doesn't seem that impressive - maybe a technology thing, but I can't think of what theory that existed 100 years ago it would have violated.

Also, objects passing through walls? What do you mean and what theory?

Objects going faster than the speed of light? Not possible under today's theories - can you be more specific?

After mars, the next horizon is asteriod mining. I am personally anxious to get my hands on some of those exotic ferrites.
Quick question: how much, per pound or kg, do you think an exotic ferrite need to be worth to make mining it economically viable with technology likely to exist in the next 50 years? $10,000 / lb? $100,000 / lb? Sorry, asteroid mining isn't happening in our lifetime.

And can the political talk - not the place for it.
 
  • #41
drag
Science Advisor
1,062
0
russ_watters said:
Could you be more specific? A magnet balancing an object in midair doesn't seem that impressive - maybe a technology thing, but I can't think of what theory that existed 100 years ago it would have violated.

Also, objects passing through walls? What do you mean and what theory?
I suppose Allah meant superconductors and stable magnetic
levitation. And abviously QM with that second remark.

But, that's all besides the point. Even today, as we speak, there
are new discoveries in physics. And yes, it doesn't seem like it
could make much of a difference, but people didn't think they'd
need a telephone at first, either.

Like I said this is not something that I believe we can discuss
in any productive manner, we just don't know what'll happen.
But, for one thing, if we let history be our guide, I think technology
will go very far, and in space as well. And, many of the REAL limmits
we recognize today may very well dissappear tomorrow.

Peace and long life.
 
  • #42
37
0
Russ

http://www.popsci.com/popsci/science/article/0,12543,577754,00.html

EARNSHAW'S THEOREM--stable magnetic levitation was thought impossible for 150 YEARS, until the 1990's.

Most of QM defies the laws of physics.
but in particular,

Particles under QUANTUM TUNNELING have been know to go faster than the speed of light and frequently pass through walls and other objects.
http://www.comcity.com/distance-time/The%20Speed%20of%20Quantum%20tunneling.html#4.3%20The%20speed%20of%20quantum%20tunneling [Broken]
http://www.physicspost.com/articles.php?articleId=173&page=1 [Broken]

Bell's Theorem developed like 40 years ago challenges most preconcieved notions about the universe. http://www.upscale.utoronto.ca/GeneralInterest/Harrison/BellsTheorem/BellsTheorem.html

As for AM, most of those asteroids have more iron in them then all the iron that has ever been mined from the Earth. All you would need is ONE! Technology-wise, Necessity is the mother of all invention, i.e. if we want we will get to it.

As for the political talk, I was simply defending my president against that flaming liberal paul.
 
Last edited by a moderator:
  • #43
Integral
Staff Emeritus
Science Advisor
Gold Member
7,201
56
As for AM, most of those asteroids have more iron in them then all the iron that has ever been mined from the Earth. All you would need is ONE! Technology-wise, Necessity is the mother of all invention, i.e. if we want we will get to it.
Humm... Let's see.... Just what is the core of the Earth composed of... iron? Now why in the world would we want to spend a nation into poverty to bring a small iron rock to a HUGE iron rock????

But even if you could find an economically sound method and had a use for (leo manufacturing?) Why would you have to send a man on the trip?

For all of the rhetoric in this thread there has not been a single viable reason presented why a man must to sent any further then LEO.

We can explore the solar system and even venture into deep space without a man ever leaving the surface of the earth. Any mission that includes a man changes the very nature of the mission. If the intent is gathering of scientific information, that will become secondary to keeping the men on the mission alive. Vital instrumentation will be left behind because men need air, food, and water. Then when the mission with men is safely on the surface of Mars, or where ever, sooner then later a situation will arise that the is NOT in the expertise of the small group sent. It will be necessary to communicate with the earth, where a committee of scientist will meet, they will analyze the transmitted data, and relay to the on site humans their decisions....

Does this process sound familiar? Is not this EXACTLY what is happening with the current Mars Rovers? So we have gained NOTHING by sending men, we have only spend huge sums of money to guarantee the safety of men who have no real purpose to begin with.

You must consider that in order to gain the expertise necessary to evaluate such data as will be gathered on these missions requires years of schooling. Who will be sent? Most NASA astronauts are pilots first and scientists ....

YIKES! Look at the time.... Gotta go!
 
  • #44
17
0
Robots are nice and all, but the real interesting thing about mars missions would be the permanence of it all.

If we can keep people alive on Mars for a year with some margin allowed for problems, why not push it and see how we inhabit other planets?

Either we go or we don't. If people don't go, humans at some point will cease to exist.

If we do go and we learn from it, humans will continue to exist as long as there is a star within reach.

We may even get to the point that we don't necessarily need power from stars to survive unaided.

Robots can't procreate. Humans can and enjoy it. If there is a way for people to live somewhere other than earth, people will compete for the opportunity.

By not going further than low earth orbit we are imprisoning our own species. I personally don't think that's a good thing.
 
  • #45
Integral
Staff Emeritus
Science Advisor
Gold Member
7,201
56
There can be no permanence for humans on Mars as long as there is no viable economic reason for being there. The expense of maintaining a permanent colony of tourists would be huge, how do you propose to pay for it?

Do you not think that it is wise to figure out how to make the journey with 100% confidence before committing huge amounts of money on a single shot mission. This is what is planned, there is no permanent colony in the works so why is that even mentioned. We can make many flights with robotic equipment, and gather more data then can be analyzed in the next decade without a man leaving the surface of the earth. When we can sent a robot to Mars with certaintly of its safe landing on the surface then perhaps we will have the knowledge and expreiance to send humans. Meanwhile, Robotics can discover if there is something of value out there and robotics can harvest anything of value that is found. A man in space can only consume air and food which must be sent with him, he can not do a single thing that cannot be done remotely. A sense of adventure or because it is there is simply not a good enough reason to waste piles of resources for a man in space.

I think it is completely foolish to dream of man in the stars as a solution to the problems we have here on earth when Physics is very clear....MAN WILL NOT JOURNEY to the stars.

Sure there could be some huge breakthrough that will change that, but until that breakthrough happens we MUST plan on being stuck on this rock till the sun novas. If a break through occurs it will not be done on a Martian colony but right here on earth in the office at some university.
 
  • #46
37
0
good pts

True, robots can send data back to earth better than a human could and men do consume resources and there are bigger problems back home... Similar arguments were made 400 years ago when America was discovered save robots of course. Why not simply send slaves? We would force them to consume almost nothing and they can report as well as any European can. The slaves can do anything that a European can do so why not send them?

I will continue to say that necessity is the mother of all invention. Since the dawn of man, if there was a river, sea, or ocean that we needed to cross then we built ships to do it. Space is the ultimate ocean and when we begin to understand the nuances of space travel, then space travel will become cheaper and easier. For example, I think it would be good to know how exactly radiation builds up on different hulls when a craft has been in space for years. However, I agree with you that a major breakthrough in propulsion will occur in a lab not in space. Still, the opposite seemed to occur in seafaring.

Man in the stars is a solution. It seems like there are a couple people here saying "omg, oil will be gone in 50 years and other bs," but Titan has an atmosphere and literally oceans made up of a compound very close to natural gas.

True the Earth has a molten iron core, but we do not want that iron. We want the exotic ferrites like Fe23Cr(?). Metals that do not exist on Earth would be extremely valuable to study and may lead to more breakthroughs.

The theme of your post is that we should not waste our time with space travel. Do you think that going to the moon was exciting? Do you think that a trip to Mars would be exciting? Well, many did and do (including me) and that influenced many to learn about space travel and the whole aerospace industry. In fact, technology has come out of the apollo space program that has been beneficial to society. http://www.sti.nasa.gov/tto/apollo.htm And face it man, Robot exploration is not exciting. If we did as you suggested, then fewer people would care about space exploration and we would indeed be doomed to existence on one planet.

I do not agree with you that we need 100% confidence for a mission because you can never have 100% confidence. There is always something to create uncertainty, like the weather at high altitudes is estimated not measured. However, I do agree with the notion that we need a very high level of confidence, which we have.

Again, I am going back to the 17th century. Jamestown was not economically viable for decades, but it was a starting point. A starting point is exactly what we need if we want to inhabit Mars.
 
  • #47
17
0
Aha, a starting point. Necessity is the mother of invention, huh?
As for mars, we've had the ability to go there for quite some time, its just the engineering of the details that improved over the time that we have had since the apollo program.

Mars is interesting because of the resources on the planet. Just about every scheme I've seen or heard of for landing there relies on self-sufficiency and living off the planet. Of course, a huge amount of equipment would need to be sent at first. However, if we design the martian craft right, we could go there cheaply (relatively) and continually.

What I personally think has going for it is this particular project: http://msnbc.msn.com/id/5025388/

This idea is radical and useful because it strays from the conventional notions that we have to use multiple stage rockets to get to space. This blimp gently floats as high as its buoyancy will take it, then takes over a week to get to orbital velocity using an ion engine.

What's even better is the cost to go to orbit. I saw predictions of the cost in another article as low as ONE dollar per TON per MILE. That means 1 ton of equipment orbiting at 200 miles LEO would cost $200 dollars by that prediction.

Of course, predictions can be particularly quirky and are known to be wrong, but even if the cost were 10, or 100, or 1000 times more than they predict, that is still the cheapest launch vehicle ever.

Another nice note from the article: "Powell intends to conduct an ion engine test at an altitude of 100,000 feet by the end of this year."

It seems like this is going to happen.

SpaceshipOne is proving that a lot of people DO have interest in putting money toward space. Mojave is booked up, and Paul Allen (Is that the right guy?) dumped something like 20 million dollars on the project. With the large amount of capital concentrated in the hands of a few people instead of smeared out across the whole population, large business owners could fund over a billion dollars for a PRIVATE mars program. The problem is the drive to do it, and the support of the rest of the population to encourage such a thing.

As the price to launch continues to fall, and with platforms such as the blimp that could potentially massively reduce the dangers of getting to LEO, we’re on the base of a wave moving toward martian shore. IT WILL HAPPEN. Unless people lose the dream and will to do such things, and as long as the USA continues to have large amounts of money concentrated into the hands of the capable, it will be our future.
 
Last edited:
  • #48
drag
Science Advisor
1,062
0
Greetings !
aeroegnr said:
What I personally think has going for it is this particular project: http://msnbc.msn.com/id/5025388/
Don'no... that dude sounds totally out there to me. You got'ta
bring your huge airship with cargo there - that is remotely possible,
but ion engines ? Sounds like a bad joke to me. The scale of
ion engines one would need... and where would all those many
MWatts and more come from. Nah... ain't gon'na happen.

As for LM's high altitude airship design, they're actually not the first
to think of it and design it, but they do have a financial advantage
over the Israelis for example. In the past few years the development
and cost reduction of solar panels, accumulators, helium containing
materials and other technologies enabled such designs. It seems very
likely at this time that rather sooner than later such high altitude
airships, carrying several tons of cargo in addition to their own
weight and cruising at high altitudes around 65-70,000 feet with
a huge cover radius would replace many if not most communication
settelites as well as fulfill many other purposes like navigation,
observation and more while reducing the need for settelites and
aircraft to do the same.

So basicly, if we wan'na see more space activity - we should
round up all of'em airship lovers and burn'em at the stake
before the slow businessmen realize the apparent advantages...:biggrin:

Live long and prosper.
 
  • #49
17
0
If he's trying an engine run before the end of the year, there must be something to it. As far as energy consumption goes, I'm looking up some facts now...

Another article:

http://www.space.com/scienceastronomy/solarsystem/deepspace_propulsion_000816.html

"Easy on xenon

Yet Deep Space 1's engine only consumes 3.5 ounces (100 grams) of xenon per day, taking about four days to use up just 1 pound (0.4 kilogram). Its solar panels generate just 2.5 kilowatts of power, the equivalent of 25 100-watt light bulbs."

From the Deep space 1 press kit:

Weight of 1080 pounds (490kg)
Power: 2400 watts

I dunno, it doesn't seem like it would take "megawatts" to power something to orbit. Sure, it'll take more time the less energy is used until a small amount atmospheric friction overcomes the power of the ion thruster, but it can be done.

Also, that DS1 was powered with solar energy. If the blimps use some kind of alternative power source, more thrust could be had along with a faster time to orbit.

But what is the respective mass of the blimp with payload? I doubt we're talking about a 1000 fold difference in power requirements.
 
  • #50
enigma
Staff Emeritus
Science Advisor
Gold Member
1,752
13
aeroegnr said:
What I personally think has going for it is this particular project: http://msnbc.msn.com/id/5025388/

This idea is radical and useful because it strays from the conventional notions that we have to use multiple stage rockets to get to space. This blimp gently floats as high as its buoyancy will take it, then takes over a week to get to orbital velocity using an ion engine.
I didn't see how they were planning on dealing with aerodynamic heating in the later stages of the ascent. You start hitting enough atmosphere to slow down a spacecraft at ~140 km. That thing flies at 35-45 km. What are they planning on doing to deal with the ~2K degree heat?
 

Related Threads on Moon/Mars - just go !

  • Last Post
3
Replies
61
Views
10K
Replies
25
Views
2K
  • Last Post
Replies
1
Views
3K
  • Poll
  • Last Post
3
Replies
70
Views
20K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
8
Views
1K
  • Last Post
Replies
2
Views
3K
  • Last Post
2
Replies
32
Views
6K
Top