Slashdot Mirror

← Back to Stories (view on slashdot.org)

Astronauts Begin Final Spacewalk To Repair Hubble

Posted by CmdrTaco on from the wave-while-you're-up-there dept.

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."

30 of 94 comments (clear)

  1. The batteries weigh what? by Sockatume · · Score: 5, Interesting

    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?
    1. Re:The batteries weigh what? by barzok · · Score: 2, Funny

      Or you could say "the batteries have a mass of <whatever> kilograms"

      Because no one would have a clue WTF the Imperial unit of mass is.

    2. Re:The batteries weigh what? by Jamamala · · Score: 5, Informative

      According to my back-of-an-envelope calculations, I get their true weight to be 1729N.

      F=GMmr^-2
      =G * Mass of earth * mass of box * (Earth's radius + Hubble orbit height)^-2
      =(6.67x10^-11 * 5.9742x10^24 * 208.7) * ((6378 + 559)x10^3)^-2
      =1729.20 N

    3. Re:The batteries weigh what? by pete-classic · · Score: 2, Informative

      Um, it's the pound. Doesn't everyone know that? 2.2 lbs to the kilo.

      While weight certainly means the force created between two masses due to gravity, it is almost always used interchangeably with mass in practice.

      -Peter

    4. Re:The batteries weigh what? by blueg3 · · Score: 4, Informative

      Pound-mass or slug, your choice.

    5. Re:The batteries weigh what? by vlm · · Score: 4, Informative

      Um, it's the pound. Doesn't everyone know that? 2.2 lbs to the kilo.

      While weight certainly means the force created between two masses due to gravity, it is almost always used interchangeably with mass in practice.

      Still messed up. Trying to compare a metric unit of mass to a imperial unit of weight using a conversion factor that only works at roughly sea level on earth.

      Metric unit of weight - Newton N
      Metric unit of mass - Gram g

      Imperial unit of weight - Pound lb (you know, like Pound Sterling being a pound of silver?)
      Imperial unit of mass - Slugs

      --
      "Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
    6. Re:The batteries weigh what? by pete-classic · · Score: 2, Informative

      Did you click the link? No one uses slugs. Pounds are commonly used to express mass as well as force (weight).

      Since there is a mass version of the pound, and it is defined in terms of kilos the conversions actually work perfectly in any (or no) gravitational field. (Though the conversion factor is exactly 2.20462262, not 2.2.)

      Seriously, click the link.

      Don't get me wrong in all of this. I advocate the metric system. But I don't understand the seemingly willful misunderstanding of the modern imperial system.

      -Peter

    7. Re:The batteries weigh what? by Maddog+Batty · · Score: 4, Insightful

      Only true if the HST + shuttle were stationary and balanced on a very tall table rather than being in orbit. As they are actually in free fall, effective gravity is zero and hence the weight is zero too.

      (Yes I do understand that gravity is acting on the HST + shuttle to keep it in orbit but there is no force required to support them which is the definition of weight)

      --
      wot no sig
    8. Re:The batteries weigh what? by Xzisted · · Score: 3, Funny

      What is the equivalent of that in unladen swallows?

      --

      Honesty may be the best policy, but apparently by elimination, dishonesty is the second best policy.
    9. Re:The batteries weigh what? by geekmux · · Score: 2, Funny

      According to my back-of-an-envelope calculations, I get their true weight to be 1729N.

      F=GMmr^-2
      =G * Mass of earth * mass of box * (Earth's radius + Hubble orbit height)^-2
      =(6.67x10^-11 * 5.9742x10^24 * 208.7) * ((6378 + 559)x10^3)^-2
      =1729.20 N

      Ah, but I see you failed to calculate the mass of your envelope...

    10. Re:The batteries weigh what? by jmn2519 · · Score: 4, Funny

      African or European?

    11. Re:The batteries weigh what? by vlm · · Score: 2, Interesting

      modern imperial system

      That, sir, is an oxymoron. Like "Military Intelligence" or "Deafening silence" or "clean coal"

      The "mass pound" and "weight pound" may be equal at sea level in a certain location or whatever, but probably not equal at any other gravitational potential, which must make for some confusing equations and explanations. Therefore, Why the willful misunderstanding? Because its icky to have the same name for inertial mass and gravitational weight/force.

      Thank you Peter for the info. Always a pleasure to converse with another five-digit UID, in our social class above the unwashed masses of six and seven digit UIDs.

      --
      "Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
    12. Re:The batteries weigh what? by pete-classic · · Score: 2, Informative

      There's no question that it's a kludge.

      The "mass pound" and "weight pound" may be equal at sea level in a certain location or whatever, but probably not equal at any other gravitational potential

      There's no "may" about it. For the Math to work they can only be equal at exactly 1G. The thing is, we never really use the "weight pound" in practice. I mean, if someone asks you what you weigh do you ask for a reference altitude (or gravitational force)? Absurd.

      Put it this weigh (yuk-yuk), if you want to buy a pound of bananas, are you looking for half a kilo of bananas? Or four and a half newtons of bananas?

      Always glad to rise above the hoi polloi ;-)

      -Peter

    13. Re:The batteries weigh what? by frieko · · Score: 2, Insightful

      You're wrong, GP is right. Weight is the amount of force needed to hold an object stationary, or equivalently, the amount of gravity acting on the object. Regardless of the actual amount of opposing force. You don't look up at a falling anvil and think, "whew, good thing it's weightless!"

  2. Watch it live by Audiophyle · · Score: 5, Informative

    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.

  3. Not above the WFC2 by Zpin · · Score: 5, Informative

    It's actually Wide Field Camera 3 now. It has been exchanged in the first spacewalk.

  4. Astronaut helmet cams by 192939495969798999 · · Score: 4, Insightful

    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 |
    1. Re:Astronaut helmet cams by Paperweight · · Score: 5, Funny

      That's the only thing holding you back?

  5. Re:Proof... by Anonymous Coward · · Score: 3, Insightful

    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.

  6. Re:Proof... by fuzzyfuzzyfungus · · Score: 3, Insightful

    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.

  7. First tweets from space by alen · · Score: 4, Informative

    http://twitter.com/Astro_Mike

    one of the astronauts is live blogging on twitter from the shuttle

  8. Comment removed by account_deleted · · Score: 5, Funny

    Comment removed based on user account deletion

  9. Re:Proof... by multisync · · Score: 2, Insightful

    Whereas, "460 pounds" makes sense to everyone (well, everyone using the imperial system) even if it's technically incorrect

    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
  10. Comment removed by account_deleted · · Score: 2, Informative

    Comment removed based on user account deletion

  11. I love NASA TV by peter303 · · Score: 3, Interesting

    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.

    1. Re:I love NASA TV by LordKaT · · Score: 3, Informative

      mms://209.73.189.79/bcpenc252181?StreamID=81684353&pl_auth=56e0ca2df8a3b81fa447c77c49dbf0f1&ht=120&pl_b=00CEBE2C2D18A488577820B4444A1179CB&CG_ID=1369080&Segment=149773

  12. Re:Proof... by Maddog+Batty · · Score: 4, Informative

    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
  13. Re:Watch it live (on Linux too) by achurch · · Score: 3, Insightful

    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.

  14. Re:Proof... by multisync · · Score: 2, Informative

    Technically the batteries have the same mass while on Earth as they do while orbiting it. The weight in orbit is zero.

    Okay, but you're talking about the lack of the sensation of weight.

    If there is no contact with any surface to provide such an opposing force then there is no sensation of weight (no apparent weight). This happens in free-fall, as experienced by sky-divers (until they approach terminal velocity) and astronauts in orbit, who feel "weightlessness" even though their bodies are still subject to the force of gravity: they're just no longer resisting it. The experience of having no apparent weight is also known as microgravity.

    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
  15. The Hubble has replaceable batteries by aaandre · · Score: 2, Funny

    but the ipod and iphone can not?