Is Manned Space Flight Worth It?

[shakenbake]

Thanks for all the response, and of course I don't believe the foam is only as sophisticated as a coffee cup, only that something of the same physical mass can so befuddle NASA. There have been many scientific accomplishments in space, my question, as it now stands, is manned space flight worth the cost? Are we really achieving anything of late that could not just as easily be performed by robots? This debate has been going on at NASA for some time now. With the imminent and indefinate grounding of the shuttle fleet yet again, I'm sure it will only heat up.

Asterix;

Thanks for the clarification. You make very strong points and ask very importsnt questions. I guess that there will always be the, "Why does Man climb mountains?" or "Why do we men want to have sex with virgins?" types of questions. because, they are there!

 

[danmand]

Really? I think the Russians were very hush-hush about their own fiascos.

I think you are correct in that assumption. But the fact remain that they have have reliable technology for going to and from the space station.

 

[booboobear]

Travelling from one continental coast to another on a planet entirely suited to supporting life, is just a bit different from going out into what is essentially vast emptiness. .

The universe is far from vast emtiness , there are things out there that we can only dream about and many wonders.


The shuttle is however antiquated , I said this 20 yrs ago . Nasa needs to update propulsion systems now.

 

[Vietor]

Is art or music worth it? Is nanoscience worth it? Is cancer research worth it? Is pure mathematics worth it? Is astronomy worth it? I guess if you are starving to death, suffering from a disease that robs you of your access to higher cognition, etc., very little matters.

If, on the other hand, you are not so limited and you are able to think, dream and experience wonder, we must continue to aspire to space travel. More should be invested, not less. We should have a permanent station on the Moon. We should have a plan to visit Mars.

We know so little about the Universe. What is the dark matter, for instance, that contains most of the mass of the Universe? These are the pursuits that lift us from the nastier aspects of humankind. These are the pursuits that make us more than what we are.

 

[Asterix]

The universe is far from vast emtiness...

Actually booboo, it terms of travel, yes it is vast emptiness. Let's put it in perspective. If we consider the distance to the moon, the one place man has been to, as one unit, then Mars is 200 times as far from us. Pluto, at the edge of the solar system, is 14,850 times as far. The nearest star system, Proxima Centauri, is over 4.2 light years away, or about 24.7 trillion miles. This is equivalent to 10,400,000 times the distance between the earth and moon. To get to a star system we think might have planets even remotely like ours (Proxima Centauri most likely doesn't) is more than double that. Meanwhile propulsion science has not really changed much since the 1960's; rockets have simply gotten bigger. I don't think people realize the enormous distances involved, and the massive logistics problem of keeping a crew alive even to the edge of our own solar system. In addition, I think people take for granted the staggering amount of time it has taken for this planet, completely averse to supporting life for most of it's history, to reach the point we are at now. If the earth's history can be seen as a 24 hour day, humans didn't show up until 30 seconds to midnight. We are extraordinarily fortunate to be on the right planet at the right time.

 

[strange1]

...
I would imagine that this material is NOT really the same as styrofoam. The insuation must withstand a very high temperature, both on re-entry into the earth's atmosphere and also the high temperatures due to exposure to the sun's rays in outer space. With that said, it is an enormous task to design materials and structures for space flight. ...

1st, the external tank that was the source of the foam never reaches space. The main purpose for the insulation is the extremely cold liquid fuel inside the tank.

2nd, having seen and held samples of the insulation, there is not much observable difference to insulation foam that's used in houses (at least to the untrained eye). It's pretty amazing to see NASA's test footage of the how the foam can damage solid surfaces. The full scale test of about 1kg of foam absolutely shattered the leading edge.

3rd, on the topic of is it worth it, one of the key features of human development has been the search to do something new. As has been stated, the money invested in the space program has payed huge dividends in practical applications that have spun off from the research. A view of history would also show that when a culture is satisfied with where it is is also when that culture starts to decline (or at least other cultures surpass it).

 

[Asterix]

We already have the technological know-how to transform Mars into a habitable planet, it will indeed happen someday.

Really. Mars has perhaps a few % points of the magnetic field of earth, leaving it entirely vulnerable to having whatever meager atmosphere that still exists continually stripped away by solar winds. Care to back up this statement?

 

[incognito]

Is manned space flight worth it? Damn straight it is. As Captain Kirk even said "...risk, risk is our business gentlemen. Thats why we're aboard her."

 

[incognito]

BTW, terra-forming is still theoretical but possible but not with current technologies. Like Astrix said, Mars has a weak EM field and would not be able to
bear the punishment of the solar winds, nevermind an atmosphere. Also, a viable atmosphere needs just the right amount of gravity to keep it from floating away and i don't think Mars has sufficient gravity for it. I could be wrong though.

 

[Asterix]

If Mars had a significant magnetic field, it would have more than enough gravity to hold an atmosphere, though much less than ours. Currently Mars has an atmosphere about 2% our own, with a very low oxygen content.

 

[irlandais9000]

If Mars had a significant magnetic field, it would have more than enough gravity to hold an atmosphere, though much less than ours. Currently Mars has an atmosphere about 2% our own, with a very low oxygen content.

Magnetic fields are dependent on gravity, not the other way around. Gravity is a function of two things only, the mass of an object and how far you are from the center of gravity from that object. The more massive the object, the higher the gravitational force it exerts, and the farther away you are away from the object, the lower the gravity.

Titan, a moon of Saturn, is about half the mass of Mars, but still has an atmosphere one and a half times thicker than the Earth's, so Mars indeed has enough gravity to support an atmosphere.

 

[Asterix]

I'm sorry, but I believe you are wrong. Magnetic fields are mostly determined by core activity and iron content. If you think I am wrong do a little research. Many people confuse gravity with magnetic force.

 

[irlandais9000]

Really. Mars has perhaps a few % points of the magnetic field of earth, leaving it entirely vulnerable to having whatever meager atmosphere that still exists continually stripped away by solar winds. Care to back up this statement?

This is a distinct possibility without terraforming. However, terraforming would indeed make the atmosphere thicker. You check out the works of Robert Zubrin, a prominent researcher in this area.

Astronomers and physicists are in wide agreement on the theoretical possibility of terraforming. The devil is in the details. Some feel we can make it work, but some feel we will never be able to fine tune it to get the exact desired result. But whether it's fine tuned or not, the concept itself is sound.

Mars' atmosphere is mostly carbon dioxide. It is very thin, but it currently has enough to sustain plants. Right now, we could put greenhouses on Mars, and plants, which need carbon dioxide to survive, could grow.

The point of the plan is to build factories and mine substances on Mars, and burn them in the factories. These gases would create a greenhouse effect, and increase the temperature. Eventually the plants could be grown outside the greenhouses in equatorial regions. As the atmosphere becomes warmer, less hardy plants could be planted, and eventually trees. Eventually, the plants and trees will provide enough oxygen for animals to breathe.

And before someone here dismisses the greenhouse effect, keep in mind that the only debate about the greenhouse effect is how much it is, and how it works in combination with other factors. It is silly to deny the greenhouse effect, all one needs to do is sit in their car on a hot day with the windows closed to see what the greenhouse effect does. This comment isn't directed at you, Asterix, just to those on here who have denied it before.

 

[irlandais9000]

I'm sorry, but I believe you are wrong. Magnetic fields are mostly determined by core activitiy and iron content. If you think I am wrong do a little research. Many people confuse gravity with magnetic force.

Indeed, you are correct, they are determined by core activity and iron content. And, in an indirect way, magnetic fields depend upon gravity , as gravity is necessary in the first place. And you are right, people confuse gravity with magnetic force, I thought that was what you had done.

In your previous post, you stated "If Mars had a significant magnetic field, it would have more than enough gravity to hold an atmosphere". That was the statement I was addressing, and your statement appears to say magnetic fields cause gravity or affect it somehow. But a magnetic field does not determine or cause gravity in any way. The addition of a magnetic field would not give Mars a greater gravitational pull. Adding the field could affect the atmosphere by attracting and repelling different gases, but the field does not change the gravity of Mars itself.

 

[Asterix]

This is a distinct possibility without terraforming. However, terraforming would indeed make the atmosphere thicker. You check out the works of Robert Zubrin, a prominent researcher in this area.

Astronomers and physicists are in wide agreement on the theoretical possibility of terraforming. The devil is in the details. Some feel we can make it work, but some feel we will never be able to fine tune it to get the exact desired result. But whether it's fine tuned or not, the concept itself is sound.

Mars' atmosphere is mostly carbon dioxide. It is very thin, but it currently has enough to sustain plants. Right now, we could put greenhouses on Mars, and plants, which need carbon dioxide to survive, could grow.

The point of the plan is to build factories and mine substances on Mars, and burn them in the factories. These gases would create a greenhouse effect, and increase the temperature. Eventually the plants could be grown outside the greenhouses in equatorial regions. As the atmosphere becomes warmer, less hardy plants could be planted, and eventually trees. Eventually, the plants and trees will provide enough oxygen for animals to breathe.

The point is that without any appreciable magnetic field, Mars can't hold onto an atmosphere, gravity or no gravity. Both are required. All the technology in the world now or tomorrow, isn't going to change that. It's current atmosphere is less than 2% ours, and nearly all carbon dioxide. Any greenhouses would certainly have to be self contained. If you think there are not signifcant problems with such a concept, look into the failure of biosphere and the problems they had with the buildup of CO2. I'm not sure what the point of setting all this up on a barren planet would be, when the same could be done on any desert here on earth, with the benefit of there being oxygen and also 46 million miles closer. If we want a challenge as a culture it should be preserving what we've got. I think we should be prepared to live here for at least the next millenium, before we can realistically shop around for a new home. Refer to my post on distances in space.

 

[irlandais9000]

Any greenhouses would certainly have to be self contained. If you think there are not signifcant problems with such a concept, look into the failure of biosphere and the problems they had with the buildup of CO2.

At first, it would be self-contained, that's the whole point. It would be a gradual process. And as far as buildup of CO2, that would be fine, plants love it. Mars would not be habitable until generations of plants produced enough oxygen anyway.

 

[irlandais9000]

The point is that without any appreciable magnetic field, Mars can't hold onto an atmosphere, gravity or no gravity. Both are required.

Mars is already holding onto a significant atmosphere. Compared to ours, it is thin, but compared to most bodies in our solar system, there is a lot there.

 

[irlandais9000]

. If you think there are not signifcant problems with such a concept, look into the failure of biosphere

That's comparing apples and oranges. The biosphere was designed for human habitat. The terraforming of Mars would be designed for survival of plants (for the first several hundred years, anyway).

 

[irlandais9000]

Refer to my post on distances in space.

I am aware as anyone on the distances involved in space (not that any of us can realistically grasp the immenseness involved).

Mars is 1.5 AU from the Sun. Alpha Centauri is over 4 light years away. The center of our galaxy is 30,000 ly away, and Andromeda is 2 mill. ly away. The observable universe stretches around 15 bill. ly in every direction.

We may never get out of our stellar neighborhood, but we may someday explore nearby stars. NASA researched this as long ago as the 1960s with Project Orion, which would involve using a "scoop" that would gather up hydrogen atoms in space and use them for fuel as the ship moved along. The project could realistically be implemented within 100 years. Engineering difficulties are the problem, a major overhaul of theoretical physics is not needed.

Since Project Orion ships could move at around 10 percent of the speed of light, nearby stars could be reached in decades.

But seeing that you are aware of distances, I am sure you know that Mars is only a few months away with current technology.

 

[Asterix]

Mars is already holding onto a significant atmosphere. Compared to ours, it is thin, but compared to most bodies in our solar system, there is a lot there.

We have a different interpretation of what constitutes, "a lot there". Actually, I was wrong. The density of Mars' atmoshpere is less then 1% Earth's, not around 2% as I thought. I stand by my statement that without a global magnetic field, Mars can't hold onto a significant or sustainable atmosphere. With only a meager atmosphere, the temperature on Mars averages around -60 degrees celsius.

http://science.nasa.gov/headlines/y2001/ast31jan_1.htm