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Astronauts Begin Final Spacewalk To Repair Hubble
An anonymous reader writes "Astronauts John Grunsfield and Andrew Feustel began the fifth and final spacewalk of their Hubble Space Telescope repair mission this morning at 8:20AM. During their spacewalk the two will install the second battery group replacement in an equipment bay above the Wide Field Camera 2 and next to the compartment where the first battery set was installed on the second spacewalk. Each of the battery module weighs 460 pounds and contains three batteries. The batteries provide electrical power to support Hubble's operations during the night when there's no sun to power the solar arrays."
I'm willing to bet that the batteries don't weigh anything right now. ;) Of course using "mass" as a verb is just taking the piss, so I won't do that. I'm sure someone will.
No kidding!!! What do you say at this point?
Doing my final upgrade on my system with AGP. You just know this is it :(
-- if you mod me down, I will become more powerful than you can possibly imagine
Check it out on NASA TV if you haven't had the chance yet. Viewing Hubble the way the astronauts see it is a neat experience.
It's actually Wide Field Camera 3 now. It has been exchanged in the first spacewalk.
Let me just say, thanks NASA for the astronaut helmet cams! That footage lets me live out my astronaut fantasies without all the space-induced nausea and military training.
stuff |
Seems like it would have been a perfectly valid statement if they added ".... on Earth." to the end of the sentence.
Would you prefer they only talk about the mass of objects in space? (something that wouldn't make sense to the majority of their readers)
Whereas, "460 pounds" makes sense to everyone (well, everyone using the imperial system) even if it's technically incorrect.
There are two possibilities:
1. "Science" Journalist studied journalism in journalism school. He writes ok; but his only science credentials involve being able to "rewrite in his own words" NASA press releases.
2. Science Journalist is a perfectly decent dude, and submitted a story with a mass in kilograms value. He was then smacked down by an editor for violating "standards" that require using imperial measures in the US. Since, as everybody knows, a kilogram is 2.2lbs universally, a simple multiplication brought the copy into compliance with correct standards.
http://twitter.com/Astro_Mike
one of the astronauts is live blogging on twitter from the shuttle
They fixed everything they supposed to during the first four space walks except for part of an instrument that was to far gone. They fixed some things that werent even deisgned to be serviced.
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Well, technically the batteries weigh the same while on Earth as they do while orbiting it, they're just falling at the same rate as the shuttle, astronauts and Hubble, so they appear weightless. Are you "weightless" while skydiving?
I don't care why you're posting AC
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I've been listening to and occasionally watching all the space walks streaming live on NASA TV while at work. Thats one video site they havent banned yet. I'm listening to the fifth space-walk now. The view is straight down at earth behind the shuttle.
Every once in a while I hear them count off. I think they are counting seconds they apply a tool, but I haven't been paying close attention.
Technically the batteries have the same mass while on Earth as they do while orbiting it. The weight in orbit is zero. (which is the point the above are making)
See here: http://en.wikipedia.org/wiki/Mass_versus_weight
wot no sig
Well, technically the batteries weigh the same while on Earth as they do while orbiting it, they're just falling at the same rate as the shuttle, astronauts and Hubble, so they appear weightless. Are you "weightless" while skydiving?
Not exactly. Weight=Mass*Gravity, therefore as gravity decreases weight decreases (assuming the mass of the batteries didn't change).
Are you "weightless" while skydiving?
Only briefly. Once you hit terminal velocity, there is no longer any sensation of falling (no acceleration). For the vast majority of your dive, you "weigh" the same as you do on the ground. Instead of being held up by the floor or a piece of furniture, you are held up by a (relative to you) fast-moving updraft.
If it redirects you to the "no player found" page (as it did for me), try:
mplayer -playlist 'http://playlist.yahoo.com/makeplaylist.dll?id=1369080&segment=149773'
(The original link is http://www.nasa.gov/55644main_NASATV_Windows.asx , but MPlayer doesn't seem to be able to handle multiple levels of playlists.)
As one who (perhaps from Kubrick's 2001) had a sense of EVA actions being slow, deliberate things, it's neat to see that the work's going practically as smoothly as if it was being done in a lab.
Okay, but you're talking about the lack of the sensation of weight.
I wasn't confusing mass with weight, but you still need to exert force to support an object in a gravitational field, and the measure of that force is its weight. The fact that we're in free fall and the object is weightless relative to us doesn't change that.
(IANAAP, so correct me if I'm wrong).
I don't care why you're posting AC
Considering the Hubble's orbit is 96-97 minutes, When exactly would it be night for the hubble? Or do the batteries click on and off every other 45 minutes? That's one heck of a recharge/discharge cycle.
_ _ _ Go for the eyes Boo! GO FOR THE EYES!
Thanks much.
> Seems like it would have been a perfectly valid statement if they added ".... in bed." to the end of the sentence.
Fixed that.....
Weight is the force resisting gravity. If you're in orbit, you're no longer resisting it, so you don't have any weight.
No kidding!!! What do you say at this point?
Is the audio feed delayed? What happens if an astronaut lets loose an f-bomb when a tool goes drifting off?
Have gnu, will travel.
You're resisting gravity by moving tangentially at the same rate as you are falling toward the center of the body you're orbiting. So your weight would be the amount of force necessary to maintain your tangential velocity.
I don't care why you're posting AC
but the ipod and iphone can not?
I had fun thinking about that example, it's not obvious. To understand it, realise that the skydiver reaches constant (terminal) velocity eventually, and therefore is no longer experiencing acceleration due to gravity. The force that stops him accelerating is the air resistance, which has become exactly equal (and actually physically equivalent) to his weight. A skydiver at terminal velocity is no more weightless than a man lying on his face a lift which is descending at constant speed. Another good example is neutral buoyancy. You're not weightless in that case, it's just the bouyancy is exactly equal to your weight. It's an even harder thing to get your head around because in that case the supporting force is much gentler and more evenly spread out.
The astronauts are different, because they're not experiencing any opposing force. They're in a pure free fall, under constant acceleration due to gravity. Perpendicular to the tangent of their orbit, to be exact. That constant, equal acceleration of all the objects is what makes free fall so different to other experiences.
No kidding!!! What do you say at this point?
The last space walk is suppose to last 6 hours.
That is incredibly dangerous to be outside for that length of time in such primitive suits.
I wish them good luck however, and pray they return safely.
God speed!!
-Hackus
Got Geometrodynamics? Awe, too hard to figure out? Too bad.
To elaborate on that, the ship stays in orbit by virtue of not resisting gravity! The pseudo-force (numerically equal to the ship's weight, but not the same force) from the gravitational attraction is what curves the ship's orbit. Without that force pulling the ship inwards (like the force on the string when you whirl a yo-yo above your head), it'd be a straight line.
No kidding!!! What do you say at this point?
Why would the OP link is story to some obscure third party blurb site when a direct link to WWW.NASA.GOV would make far more sense.
You could even watch live at the Nasa site:
http://www.nasa.gov/multimedia/nasatv/index.html?param=public
Sig Battery depleted. Reverting to safe mode.
3. Science Journalist knows that any reasonably intelligent person will understand the implied "... on the surface of the Earth" appended to the phrase "weighs X pounds," and really doesn't care about that tiny minority of readers whose chief joy in life is showing off how clever they are by telling everyone, in a breathless OMG-I'm-the-first-person-to-notice-this-EVAR tone, that mass and weight are not the same thing.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Hmmm. Was duracell used on that electric wrench?
I prefer the "u" in honour as it seems to be missing these days.
Option 4: They know that pounds are a unit of mass, in addition to weight, and are thus actually smarter than the pedants on slashdot.
HA HA JUST KIDDING HOW COULD THAT BE?!
The enemies of Democracy are
So, in orbit your weight depends on the density of matter around you, and would be zero in a perfect vacuum?
That doesn't sound right.
Also, defining a force perpendicular to gravity as resisting gravity makes little sense.
The enemies of Democracy are
I think you need to read this.
"I have never let my schooling interfere with my education." --Mark Twain
460 pounds. That makes it 208.656755845 kilograms, right?
Astronaut floating in shuttle "Ahhh they are pretty light up here."
"... but they are massive."
Which is actually pretty close to a real quote from an astronaut from ages back.
Those batteries are not going to be easy to move around, just because they are in freefall.
The enemies of Democracy are
There's also a 1200k stream available: http://playlist.yahoo.com/makeplaylist.dll?id=1368163
modern imperial system
That, sir, is an oxymoron.
I put forth a compelling argument for the United States to join the world with the International System of Units. Forward this to your friends who still think that ounces (fluid ounce or international avoirdupois ounce? British or U.S. fluid ounce? Apothecary ounce?), pints, and inches are the way to go.
Dr Superlove 300ml. I use my powers for awesome
The really clever thing about this was, they never went to the moon six times, they tried not to go to the moon actually seven times, 'coz one time they failed in their attempt not to go the moon, but luckily the three astronauts survived their attempt at not going to the moon.
It's called an elephant's trunk whereas it is in fact, an elephant's nose, a nose by any other name would smell as sweet