Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
Space Science

Successful Launch of ESA's Herschel and Planck 121

Posted by CmdrTaco
from the round-and-round-they-go dept.
rgarbacz writes "Today at 13:12 GMT, the ESA launched successfully new and long-awaiting spacecraft: Herschel, the infrared telescope with a 3.5m mirror, and Planck, the CMB mapper. The spacecraft were carried by the Ariane-5, which lifted off from Kourou in French Guiana. They will stay in L2 to perform the research. This launch is one of the most expensive and important missions of the European Space Agency. Planck will measure the CMB with an accuracy more than 10 times better than the previous mission, WMAP. Because of this high sensitivity, both spacecraft are cooled to temperatures close to absolute zero by on-board liquid helium; staying in L2 is very helpful to maintain this state. Both spacecraft are designed to observe the Universe at its infancy: Herschel by observing the first stars and galaxies (whichever came first), and Planck by scrutinizing the first photons that were set free, making up the cosmic microwave background radiation."
This discussion has been archived. No new comments can be posted.

Successful Launch of ESA's Herschel and Planck

Comments Filter:
  • Re:SuperAccurate (Score:4, Informative)

    by Anonymous Coward on Thursday May 14, 2009 @10:54AM (#27951995)

    The correct term would be inaccuracy. Calling it accuracy is misleading, but very common.

  • L2? (Score:3, Informative)

    by bradgoodman (964302) on Thursday May 14, 2009 @10:56AM (#27952025) Homepage
    What is "L2"?
  • FFS (Score:1, Informative)

    by 1u3hr (530656) on Thursday May 14, 2009 @10:59AM (#27952073)
    "new and long awaiting spacecrafts....both spacecrafts are cooled...Both spacecrafts are designed"

    Plural of "spacecraft" is "spacecraft".

    English, do you speak it?

  • by whathappenedtomonday (581634) on Thursday May 14, 2009 @11:00AM (#27952077) Journal
    Herschel is supposed to complete its mission in three years, Planck in only 15 months. After the helium supplies have evaporated, their missions end. They won't be repaired / serviced, because they are too far away to be easily reached with a shuttle. That's what local news here say.
  • Re:L2? (Score:5, Informative)

    by Morphine007 (207082) on Thursday May 14, 2009 @11:00AM (#27952083)
  • Re:L2? (Score:5, Informative)

    by Ornedan (1093745) on Thursday May 14, 2009 @11:01AM (#27952095)

    Lagrange point. Location where the gravitic pulls of some objects cancel each other out. In this case, it's Earth and Moon.

  • Re:L2? (Score:3, Informative)

    by Anonymous Coward on Thursday May 14, 2009 @11:02AM (#27952105)

    Lagrange point 2, one of the 5 locations in space around an orbiting body where the gravity wells from the major surrounding bodies cancel each other out, providing a sort of "still point" in space.

    http://en.wikipedia.org/wiki/Lagrange_point

    Ah how, how, how, how....

  • Blame rgarbacz (Score:5, Informative)

    by mangu (126918) on Thursday May 14, 2009 @11:02AM (#27952113)

    It seems like the summary writer didn't understand TFA. Quoting from ESA:

    Planck is designed to 'see' the microwaves and, in practice, it will detect them by measuring temperature. That temperature is already known to be about 2.7K (which is very cold, about 270C, near absolute zero). It has been measured to be 2.726K all over the sky to three decimal figures. This degree of accuracy in the measurement may seem good enough, but much more precise measurements are needed.

    The older measurements that Planck is trying to improve already are accurate to 0.1%.

    It seems like someone got confused with the coincidence that the temperature of the universe, 2.7 K, is about 1% of the temperature of freezing water, 270 K.

  • Re:FFS (Score:3, Informative)

    by johannesg (664142) on Thursday May 14, 2009 @11:06AM (#27952173)

    "new and long awaiting spacecrafts....both spacecrafts are cooled...Both spacecrafts are designed"

    Plural of "spacecraft" is "spacecraft".

    English, do you speak it?

    Actually Herschel and Planck are _two_ of the most expensive and important missions. But maybe we are being too hard on the author of this piece, who may not have english as his native language.

    Indeed, the working language of ESA is something known as "franglais". It sounds like french and has grammar like french, but uses mostly english words. From experience, a communication like the article summary is actually pretty good by ESA standards...

  • by Anonymous Coward on Thursday May 14, 2009 @11:06AM (#27952181)

    During the launch commentary they mentioned that the scopes are launched with a 3 year supply of helium. I'm pretty sure repair missions to L2 would be pretty impractical.

  • Re:L2? (Score:3, Informative)

    by Morphine007 (207082) on Thursday May 14, 2009 @11:26AM (#27952439)
    Sorry, GP ... I just realized that posting the wiki link like that was basically akin to saying "L2wikipedia, noob", but it wasn't intended that way: The article doesn't actually say that the "L2" where the spacecraft are "staying" is actually the L2 Lagrange Point. Basically, as the wiki mentions and as others have stated, it's one of the 5 well known points where gravitational forces between the sun, moon and earth all cancel each other out. So the satellites can basically "hover" in the exact same position (relative to the earth and the sun) without having to move. For these particular satellites, that allows them to always stay in the earth's shadow, and, when their positioning (relative to the sun) allows for them to study a particular area in space, they won't have the earth periodically passing between them and whatever they're studying.
  • by imsabbel (611519) on Thursday May 14, 2009 @11:34AM (#27952531)

    Well, that's because the space is too hot.

    Even without the sun.

    They are trying to measure the CMB. If you are not colder than outer space, most of the radiation would just come from the telescope itself...

  • by whathappenedtomonday (581634) on Thursday May 14, 2009 @11:42AM (#27952653) Journal
    "In order to study the coolest places in the Universe the Herschel instruments must be cooled to just above absolute zero. A large cryostat surrounds the instruments maintaining an operational temperature of 1.7 K for a nominal mission lifetime of 4 years." ESA has some great info on their site. [esa.int]
  • by m50d (797211) on Thursday May 14, 2009 @11:43AM (#27952687) Homepage Journal
    I realize we, as in all space agencies, use helium or something else to keep these instruments cold, but why can't we use the coldness of space to do the same thing?

    Because what they're trying to measure is, in some senses, the temperature of space itself - the ~3K CMB. So they need the detector to be colder than that.

    Isn't there some way to use one or more of the three forms of heat transfer to keep the instruments cold enough to work without having to rely on a limited source of helium?

    No. The radiative coolers (can't really use conduction or convection in space) will keep the craft cold enough for the low frequency instrument to work, even after the helium* runs out, but to get the 0.1K that the high frequency instrument needs, there's no (good) alternative to this active cooler.

    * Well, not after the helium in its own refrigerators runs out. But it's not actively venting that, so we only have leakage to worry about there.

  • by FireFury03 (653718) <slashdot@CHEETAHnexusuk.org minus cat> on Thursday May 14, 2009 @11:52AM (#27952791) Homepage

    I realize we, as in all space agencies, use helium or something else to keep these instruments cold, but why can't we use the coldness of space to do the same thing?

    Space isn't really "cold", or rather, the terms "cold" and "hot" lose much of their meaning when you're talking about incredibly low densities like you have in space.

    If you have an atmosphere then you transfer heat by radiation and conduction. You can cool your instruments by putting them in the shade (so they don't get the radiated energy from the sun) and ensuring the atmosphere is cool so that it will conduct the heat away. The atmosphere on Earth is actually not a great conductor, but because it is a fluid you can keep the air moving so that as soon as some of the heat has been conducted to the surrounding air you move that (warmer) aid out of the way and replace it with cool air - this can be done naturally by convection or by forcing the air to move with a fan.

    In space you have practically no atmosphere, so the heat transfer is almost entirely by radiation - your instruments are essentially in a giant vacuum flask. Your satellite needs to reflect away the energy radiated by the sun, and the cosmic microwave background radiation, etc. and also radiate away its own heat (remember, these satellites contain lots of electronics and like all electronics they will generate heat). This is a pretty tall order - surfaces that radiate well are also really good at absorbing energy. - I imagine it's much cheaper and lighter to send up a load of liquid helium and dissipate the heat by letting it boil away.

  • by mmontour (2208) <mail@mmontour.net> on Thursday May 14, 2009 @11:59AM (#27952887)

    I realize we, as in all space agencies, use helium or something else to keep these instruments cold, but why can't we use the coldness of space to do the same thing?

    According to this PDF [nationalacademies.org] the Planck mission does not use liquid helium coolant (although Herschel does). Also the upcoming James Webb telescope will not use it.

  • Re:L2? (Score:1, Informative)

    by Anonymous Coward on Thursday May 14, 2009 @12:20PM (#27953163)
    That's L1, the most obvious balance point. L2 is on the other side of Earth, away from the sun. Imagine an object the mass of the Sun plus the mass of the Earth, and imagine that this combined object is located at the center of gravity of the Sun-Earth system. Orbit this imaginary object with a period of one year, and your location will be slightly outside Earth's orbit. L3 is exactly the same principle, just on the opposite side of the Sun. L4 and L5 are trickier to explain.
  • by borizz (1023175) on Thursday May 14, 2009 @12:49PM (#27953439)
    Space radiates. If we were to put a black body in space at absolute zero, after a while it would be about 2.7 Kelvin. This is because of the cosmic microwave background (which is what they're trying to measure here).

    If you have a distractor (radiation from the craft itself) as big as the thing you're trying to measure, you won't get good results.
  • by Anonymous Coward on Thursday May 14, 2009 @12:50PM (#27953457)

    The NASA/GSFC Solar Dynamics Observatory (SDO) also uses RTEMS on some of its support processors. The main processor on SDO runs the closed source VX/Works OS.

  • Re:L2? (Score:4, Informative)

    by hcg50a (690062) on Thursday May 14, 2009 @01:35PM (#27954171) Journal

    Actually, it's the Earth and the Sun. It's on the Earth-Sun line, behind the earth (from the sun's point of view), and orbits the sun once a year. They put it here because it's easier to shield the satellite from both the Sun and Earth.

    The L2 point for the Earth-Moon system is on the Earth-Moon line, behind the moon, and orbits the earth once evry 29.5 days.

"Pascal is Pascal is Pascal is dog meat." -- M. Devine and P. Larson, Computer Science 340

Working...