Donald Trump expected to slash Nasa's climate change budget in favour of sending humans back to the

originally posted by: Byrd

originally posted by: InachMarbank
I just started thinking about space program stuff pretty recently. Among other things, I can't seem to wrap my head around the gravitational intricacies of how satellites stay in orbit.

I have asked this kick off question before and run into a wall on a different site. Maybe the community here at ATS can help me see the light... Here goes...

What is the terminal velocity of an object falling in a vacuum?

Depends on the strength of the gravitational field. On the Moon, it's not going to be as fast as it would on something with the mass of Earth or of the sun.

Say, where the ISS is said to be, 210 miles altitude, where it is nearly a vacuum. Is there a terminal velocity from free falling at that altitude?
Seems the consensus is there is no terminal velocity in a vacuum...

While I love the idea of mankind finally, and rightfully, expanding into space - I'm not so sure it should be at the expense of climate change research.

Then again I guess that if we defund climate change then we'll definitely need to expand into space before we hotpot the planet!

originally posted by: worldstarcountry
a reply to: Christosterone

#ing bravo! It is about time we focus on space again, because the Chinese certainly never stopped. We cannot allow them to edge over our capabilities. I say we need to focus on constructing bases on the moon that would also be research stations. ISS can be evolved into a go between. Then we should have satellite laser weapons for the aliens that will eventually step up against us.

This, I can't stand! Saying and I quote " We cannot allow then to edge over our capabilities" is a mind-set that has kept us from truly advancing. Its all about beating the other country on this and that, but if we worked as a planet, our advancements would be far greater.

I don't care who is the first country to do this or that, as long as it benefits all of us, is the most important thing.

originally posted by: InachMarbank

Hey thanks for reply.
Yea reading in various forums, seems the consensus is there's no terminal velocity in a vacuum.
If you're free falling in a near vacuum, like the ISS is said to be, at an acceleration of 9.8 meters per second squared (gravity of earth) would you keep accelerating to infinity, because of insignificant air resistance???

Is it accelerating at said speed, or is that it's orbital velocity?

I think what's being said is that since space is a (near-absolute) vacuum, you can approach the speed of light. Gravity is what drags us down. Gravity is also what creates an orbit, or rather a perfect balance between forward momentum and the pull down of gravity.

In order to accelerate in orbit, you'd have to continue to balance the rate of forward thrust to gravity. I think this means you'd have to pull closer into earth as your speed increases. It also means you'd reach a point where the orbit was no longer sustainable.

At least, this is what my mind reasons, though I could be pretty far off here.

a reply to: Kryties

Define "hotpot". If you mean runaway greenhouse humans lack the ability to do that.

a reply to: raymundoko

That's not certain. We could perhaps warm up the ocean's depth to the critical point at which the methane hydrates dislocate and dissolve.

a reply to: SignalMal

Source a paper that says HUMANS can do that.

a reply to: raymundoko

What would you like me to look up?

Do you dispute the greenhouse effect? Or is it the range of climate sensitivity? Do you think we have less carbon to burn than is estimated?

I'm not understanding what exactly you want a source for.

a reply to: SignalMal

You made the unsourced claim humans have the ability to heat the ocean to a critical point causing methane hydrates to dislocate (assuming you mean dissociate) and "dissolve".

In any case I'm sure of the studies you are referring to and none of the purport what you claim. They all garner further research as models didn't match observations.

Here is a new article on the mismatch concerning methane.

Phys.org: Source of Greenhouse Gas Methane at Ocean

originally posted by: SignalMal
a reply to: raymundoko

What would you like me to look up?

Do you dispute the greenhouse effect? Or is it the range of climate sensitivity? Do you think we have less carbon to burn than is estimated?

I'm not understanding what exactly you want a source for.

I don't think he is disputing global climate change, but rather disputing the idea that human activity has definitively been found to be a major cause of global climate change.

I don't know the answer; all I'm pointing out is what I think he is trying to say.

I have seen studies that show that rising temperatures cause CO2 to be released from the oceans, which then raises temperatures even more -- but that original rise in temperature that starts the CO2/temperature cascade could have natural causes, such as a higher energy output by the Sun, which seems to occur on a cyclical basis.

Using clues to look back at Earth's climate over a long period of time, global temperatures had been seen to rise in the past, prior to human civilization. Plus, a rise in temperatures in the solar system in general has been measured (not just on Earth).

a reply to: Christosterone

I fear that, while idealogically a good idea, Mr. Trump has yet to be enlightened on a few things.
One is, we have been mining the moon (& possibly Mars also) for some time. By 'we' i mean a group of humans NOT under control of any government (officialy).

NASA is & has mostly been window dressing for the peeps, the real stuff goes on in total secrecy with a budget that can only be guessed at.
Holland wants to upgrade their army with 450 million over the next few years to counter the 'new russian threat'...hell you guys spend that in less than a day, as someone on the YT put it, we could fight a full-scale war with Russia for just 2 hours with that money.

If we had a few peeps together on this like Musk, Branson etc then we could get it done in less than a year, we will of course need all the tech tht is currently 'black' like the fusion reactors, particle beam stuff, FTL comms & travel, nanotech etc. Problem is everyone has their own agenda & they can't work together.
Shame really, for just 1 year's profit on the Cancer therapy pharma sugar scam ($70 Bn) they could be on the moon by next summer, harvesting all the helium-3 they would ever need for the next 300 years...........

Like i said, peeps need to be well informed before they go making rash decisions.

a reply to: Box of Rain

Close. I fully accept climate change and global warming.

What I don't accept is how much the media thinks man contributes and how bad it is for the planet.

I stand by the historical proof that life on earth has always been at the most prosperous when the global average temperature is 20c and 1-1.2k PPM co2.

Those are perfect levels for man as well, all we have to do is adapt to the coming changes.

Our money would be better invested in preparing for the future rather than trying to prevent it.

originally posted by: SignalMal

originally posted by: InachMarbank

Hey thanks for reply.
Yea reading in various forums, seems the consensus is there's no terminal velocity in a vacuum.
If you're free falling in a near vacuum, like the ISS is said to be, at an acceleration of 9.8 meters per second squared (gravity of earth) would you keep accelerating to infinity, because of insignificant air resistance???

Is it accelerating at said speed, or is that it's orbital velocity?

I think what's being said is that since space is a (near-absolute) vacuum, you can approach the speed of light. Gravity is what drags us down. Gravity is also what creates an orbit, or rather a perfect balance between forward momentum and the pull down of gravity.

In order to accelerate in orbit, you'd have to continue to balance the rate of forward thrust to gravity. I think this means you'd have to pull closer into earth as your speed increases. It also means you'd reach a point where the orbit was no longer sustainable.

At least, this is what my mind reasons, though I could be pretty far off here.

I think intro physics says the acceleration rate of a falling object in Earth's atmosphere is 9.8 meters per second squared.

And I read air resistance is what eventually stops the acceleration of a falling object (or the ground 😁)

For an example, a typical sky diver jumping from maybe a 1 mile altitude gets to a top speed of 120 mph. But when I watched the clip of Felix Baumgartner jumping from an altitude of around 25 miles, the estimate of his top speed seemed to peak at 729 mph, before his speed began to slow.

But I can't seem to figure out what the terminal velocity would be, for an object falling from an altitude of around 210 miles. It can't keep accelerating forever can it?

a reply to: intrptr

Not so true. The AF has nuclear rockets already on the book, but the no nukes in space treaty killed them. Look up NERVA project. Nuke powered thrust engines that could go to Mars in weeks.

originally posted by: dismanrc
a reply to: intrptr

Not so true. The AF has nuclear rockets already on the book, but the no nukes in space treaty killed them. Look up NERVA project. Nuke powered thrust engines that could go to Mars in weeks.

Nuclear engines are too heavy to get to orbit. Besides lets say they build them there, thats many flights Cost and fuel) to orbit carrying parts. Besides leaving a radioactive wake everywhere like the rovers on Mars and the Voyager probes, they don't land on Mars or lift off from Mars or reenter earths atmosphere after coming home. So multi stages, landers, re-entry vehicles are all still necessary. The same way they went before.

Design concepts and practicality are vastly different things. Heres a pic of nuclear powered jet engines that never go off the ground...

De Tredici photo gallery

originally posted by: InachMarbank

originally posted by: SignalMal

originally posted by: InachMarbank

Hey thanks for reply.
Yea reading in various forums, seems the consensus is there's no terminal velocity in a vacuum.
If you're free falling in a near vacuum, like the ISS is said to be, at an acceleration of 9.8 meters per second squared (gravity of earth) would you keep accelerating to infinity, because of insignificant air resistance???

Is it accelerating at said speed, or is that it's orbital velocity?

I think what's being said is that since space is a (near-absolute) vacuum, you can approach the speed of light. Gravity is what drags us down. Gravity is also what creates an orbit, or rather a perfect balance between forward momentum and the pull down of gravity.

In order to accelerate in orbit, you'd have to continue to balance the rate of forward thrust to gravity. I think this means you'd have to pull closer into earth as your speed increases. It also means you'd reach a point where the orbit was no longer sustainable.

At least, this is what my mind reasons, though I could be pretty far off here.

I think intro physics says the acceleration rate of a falling object in Earth's atmosphere is 9.8 meters per second squared.

And I read air resistance is what eventually stops the acceleration of a falling object (or the ground 😁)

For an example, a typical sky diver jumping from maybe a 1 mile altitude gets to a top speed of 120 mph. But when I watched the clip of Felix Baumgartner jumping from an altitude of around 25 miles, the estimate of his top speed seemed to peak at 729 mph, before his speed began to slow.

But I can't seem to figure out what the terminal velocity would be, for an object falling from an altitude of around 210 miles. It can't keep accelerating forever can it?

You're more or less correct, although it's a little more complicated than that. First of all the acceleration toward Earth is not uniform. As you get further away from the center of mass, the gravitational acceleration you experience from the body in question decreases. As I recall, the commonly quoted 9.8 m/s^2 acceleration of Earth's gravity is the acceleration it exerts at sea level. At 25 miles altitude above sea level, you would actually experience a little less acceleration, although I don't know the exact amount by which it decreases off the top of my head. At that altitude, he was not technically out of the atmosphere, but there is no appreciable air resistance, which is why he was able to accelerate to over 700 mph before he entered denser air, which slowed him down to our normal terminal velocity of around 120 mph.

In theory, if you were dealing with a body that had no atmosphere such as the moon or Mercury, there is no terminal velocity, however you won't continue to accelerate indefinitely because, obviously, at some point you will collide with the body. The maximum velocity you could attain would then be some function of what altitude you began to fall toward the body. Someone who knows a little more math than I do could probably figure it out in short order.

We need to set up a base on the Moon ASAP and start stress testing renewable energy technology. There isn't any oil or coal in space, but lots of sunlight.

Once we get solar and water reclamation sorted out there, colonization of Mars will be that much easier.

a reply to: Bluntone22

He certainly has quite a lot of influence over those things, wouldn't you agree?

Signing. VETO'ing. Having meetings with Congressional leadership. It's actually quite obvious he has enormous influence over such things.

originally posted by: seagull
a reply to: Bluntone22

He certainly has quite a lot of influence over those things, wouldn't you agree?

Signing. VETO'ing. Having meetings with Congressional leadership. It's actually quite obvious he has enormous influence over such things.

Yes.

And like I said in an earlier post, agencies such as NASA do not make their budget requests based solely on what they want. Instead, NASA and other agencies work closely with congress and the President's office in order to create a budget request that would be palatable to Congress and the President so it could be part of an overall federal budget that Congress might pass and the the President might accept.

So, yeah -- the President and Congress have a major influence on what NASA puts in their budget (i.e., how much money, and for what that money is earmarked).

originally posted by: face23785

originally posted by: InachMarbank

originally posted by: SignalMal

originally posted by: InachMarbank

Hey thanks for reply.
Yea reading in various forums, seems the consensus is there's no terminal velocity in a vacuum.
If you're free falling in a near vacuum, like the ISS is said to be, at an acceleration of 9.8 meters per second squared (gravity of earth) would you keep accelerating to infinity, because of insignificant air resistance???

Is it accelerating at said speed, or is that it's orbital velocity?

I think what's being said is that since space is a (near-absolute) vacuum, you can approach the speed of light. Gravity is what drags us down. Gravity is also what creates an orbit, or rather a perfect balance between forward momentum and the pull down of gravity.

In order to accelerate in orbit, you'd have to continue to balance the rate of forward thrust to gravity. I think this means you'd have to pull closer into earth as your speed increases. It also means you'd reach a point where the orbit was no longer sustainable.

At least, this is what my mind reasons, though I could be pretty far off here.

I think intro physics says the acceleration rate of a falling object in Earth's atmosphere is 9.8 meters per second squared.

And I read air resistance is what eventually stops the acceleration of a falling object (or the ground 😁)

For an example, a typical sky diver jumping from maybe a 1 mile altitude gets to a top speed of 120 mph. But when I watched the clip of Felix Baumgartner jumping from an altitude of around 25 miles, the estimate of his top speed seemed to peak at 729 mph, before his speed began to slow.

But I can't seem to figure out what the terminal velocity would be, for an object falling from an altitude of around 210 miles. It can't keep accelerating forever can it?

You're more or less correct, although it's a little more complicated than that. First of all the acceleration toward Earth is not uniform. As you get further away from the center of mass, the gravitational acceleration you experience from the body in question decreases. As I recall, the commonly quoted 9.8 m/s^2 acceleration of Earth's gravity is the acceleration it exerts at sea level. At 25 miles altitude above sea level, you would actually experience a little less acceleration, although I don't know the exact amount by which it decreases off the top of my head. At that altitude, he was not technically out of the atmosphere, but there is no appreciable air resistance, which is why he was able to accelerate to over 700 mph before he entered denser air, which slowed him down to our normal terminal velocity of around 120 mph.

In theory, if you were dealing with a body that had no atmosphere such as the moon or Mercury, there is no terminal velocity, however you won't continue to accelerate indefinitely because, obviously, at some point you will collide with the body. The maximum velocity you could attain would then be some function of what altitude you began to fall toward the body. Someone who knows a little more math than I do could probably figure it out in short order.

A satellite, for example the ISS, is said to be constantly falling, at an altitude that is almost a vacuum (miles between air particles).

And the ISS is also said to be moving basically forward around 17,000 mph, so when it falls it keeps missing the earth, because of the circle shape of the earth, and because of the forward travel speed.

So if it is constantly falling it couldn't possibly be constantly accelerating, could it?

I calculated, accelerating at 9.8 meters per second squared, would reach a speed of 17,000 mph in around 13 minutes.

And if its fall speed surpasses its forward speed, and keeps accelerating, wouldn't it eventually collide with the land or sea?

Since I can't find any reports of the ISS crash landing on earth, and I can find plenty of reports about the ISS in orbit, it must be there is a terminal velocity of this falling object, right?