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Whisper Heard From Pioneer 10
Irishman writes "NASA has heard from the Pioneer 10 spacecraft for the first time since March. Unfortunately, it is too faint to get scientific data from the craft. CNN has the story here.
Considering that the craft is twice the distance from the Sun as Pluto is and that it has spent 30 years subjected to space, this is amazing! Now if only computer manufacturers could make equipment even remotely this sturdy."
Exactly. Pioneer 10 cost ~$200 million to design and build, plus another ~$150 million to launch and operate. Here's more information on it.
From the Pioneer Status web page:
Pioneer 10 distance from Sun : 81.86 AU Speed relative to the Sun: 12.228km/sec (27,355 mph) Distance from Earth: 12.10 billion kilometers (7.52 billion miles) Round-trip Light Time: 22 hours 25 minutes
There was one more Pioneer 10 contact on 12/5/02. The Deep Space Station (DSS) near Madrid (DSS-63) found the signal but could not lock onto the receiver, and so no telemetry was received. The signal level was just under the threshold value. The uplink from DSS-14 at Goldstone, sent 12/4/02 at a power level of 325 kw, confirmed that the spacecraft signal is still there (Round Trip Light Time = 22 hr 24 min).
Project Phoenix also picked up the signal from Pioneer 10 at Arecibo in Puerto Rico.
LARRY LASHER, PIONEER PROJECT MANAGER
(Copyright NASA)
In about 2 million years it'll be in the vicinity of Aldebaran. It was sent out originally as a deep space probe.
Sending out probes is cool when we can collect info, but it's not really useful if the data isn't able to be processed.Just finding it is useful information. From this, physicists can map its path and start to make observations of what space is actually like out there. They have used the some sparse readings in the past to investigate everything from cosmic rays to gravitational mechanics.
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"Now if only computer manufacturers could make equipment even remotely this sturdy."
It's called the Compaq Nonstop Himalaya. Each processor runs every calculation twice, in parallel, and compares the answers when done--if they do not match, it tries again. If they do not match again, the processor state is saved then restored in one of the "hotspare" processors. The memory uses a special, extra high-reliability (and extra slow) ECC algorithm. The server itself has integrated battery backup, variable speed fans which adjust for the death of other fans, and each system is immensely expandable without ever being rebooted or shut down.
An acquaintance of mine works for a company which has a Nonstop with an uptime of nearly ten years.
Remember the Tandem?
Note that the Nonstop isn't much more reliable than IBM's Z series mainframes, which basically never die either.
Ironic, isn't it, that a company famous for making desktops which are essentially crap, makes one of the most reliable servers on earth?
Er, back on topic, isn't Voyager significantly farther from the sun than Pioneer 10?
Computer Science is no more about computers than astronomy is about telescopes. --E. W. Dijkstra
Just for interest, Pioneer is powered by the decay of Plutonium 238. This isn't a reactor, the decay is natural.
Communications were maintained via (1) the omnidirectional and medium-gain antennas which operated together while connected to one receiver and (2) the high-gain antenna which was connected to another receiver. These receivers could be interchanged by command to provide some redundancy. Two radio transmitters, coupled to two traveling-wave tube amplifiers, produced 8 W at 2292 MHz each. Uplink was accomplished at 2110 MHz, while data transmission downlink was at 2292 MHz. The data were received by NASA's Deep Space Network (DSN) at bit rates up to 2048 bps enroute to Jupiter and at 16 bps near end of the mission.
Is the solar system larger than the orbit of Pluto? If so, what defines it?
I'm no expert, but I believe that the edge of the solar system is generally considered where the sun no longer has any influence. Beyond Pluto (Pluto is about 39.5 AU from the sun) the sun continues to have influence in the form of solar wind (thought to go out to around 100 AU). Many scientists also believe that many object exist outside the orbit of Pluto.
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It doesn't say anything of the kind. The RF power output of Pioneer is miniscule:
Two radio transmitters, coupled to two traveling-wave-tube power amplifiers, each produced 8 W of transmitted power at S-band. source
So, we are picking up a signal from either an 8W or 16W transmitter (not quite sure if they are both used at the same time), 12 billion kilometers away. We talk to the Pioneers by sending a 325,000W signal. More power, more distance before it attenuates below the noise floor. Pump out enough power in a tight enough beam, and there isn't any reason to believe that we couldn't send signals all the way to the nearest few stars. Round Trip Time would be a bit of a pain, not to mention the time it might take to translate on both ends, but not technologically infeasible.
Exactly how much power you would have to transmit to be heard depends on many factors, such as the frequency chosen (which might be attenuated or masked by interstellar phenomena), the sensitivity of the receiver, the size of receiving dish, the directionality of the beam, the length of the transmission, the properties of the error correcting codes, the mathematical properties of the transmission (whether it could be distinguished from physical processes even IF it is received) etc. etc. etc. So I can't give you a single answer.
Barring some freak gravitational occurrance, never.
DS1 is in a solar orbit and won't be leaving the solar system.
If you don't believe me, read the last log entry.
"From my cold, dead hands you damn, dirty apes!" - CH
Yes, plutonium 238 isn't a natural isotope. You don't want a natural isotope in this application, because you want a short halflife so that there is enough decay to make a significant amount of heat, which is converted to electricity through thermoprobes. The 92 year half life is perfect. We're about 1/3 of the way through a half life, so the pile will still be outputing 80% of the heat of the original pile. Unfortunatly the thermocouples have degraded, which has reduced the power output, however it's still much better than if they'd put a reactor onto the probe, which would have failed by now.
Nope, temperature is a measure of the energy of a system. For normal objects it manifests itself as the oscillation of the atoms making up that object. At absolute zero the atoms are motionless.
Infrared radiation is a mechanism of heat transfer. Hot objects radiate in more than just the infrared though. The infrared range just happens to be where the peak for black-body radiation for objects with typical earth temperatures lies. Hotter objects (such as an incandescent lamp) have peaks at higher frequencies such as the visible range and beyond.
"From my cold, dead hands you damn, dirty apes!" - CH
Imagine, please, that you have a pipe 1m in diameter stretching from just past Earth's atmosphere to the Alpha Centauri system. (Ignore the engineering difficulties, please.)
Can you guess how much all the contents of that pipe would weigh?
Less than a kilogram.
Considerably less than a kilogram.
I would tell you just how tiny, but you wouldn't believe me. I'll let you do the math: the observed density of the universe is 2.1 * 10**-29 kilograms per cubic meter. From here to Alpha Centauri is about 4.5 lightyears, and each lightyear is 9.5 * 10**15 meters.
So we're looking at a total distance of about 4*10**16m to Alpha Centauri. Multiply that by the cross-sectional area of our pipe (.6m) and you get... 2.4 * 10**16m**3 of volume.
Multiply that by the observed density of the universe and you get...
5 * 10**-13 kilograms.
Yeah. Like I said. Considerably less than a kilogram.
Your post shows a severe lack of understanding about space. One, it's freaking cold. Two, once you get past Saturn you can pretty much write off solar flares and activity. Three, sure, there are energetic cosmic rays--but they're here on Earth, too, so Earth's no better off. (No, our atmosphere doesn't protect us in any substantial way from cosmic rays.)
If you were to stand on Pluto and turn on a cell phone, the radio signal from your cell phone would be the brightest electromagnetic signal in the sky--by orders of magnitude.
Space is overwhelmingly small, dark and quiet. Yes, there is the occasional bit of matter which can be a real royal pain in the ass... but the odds of a collision are, well, astronomical.
I don't think you understand a damn word of what you just posted, and it astonishes me that you can get a +4 moderation for being totally flipping wrong.