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Change In Experiment Will Delay Shuttle Launch
necro81 writes "A $1.5 billion gamma ray experiment, the Alpha Magnetic Spectrometer, that was to have launched aboard the space shuttle Endeavor to the International Space Station in July, has undergone a last minute design change that will change the launch date, pushing back the end of the shuttle program by at least several months. The change replaces the original liquid helium-cooled superconducting magnet with a more conventional one, which will reduce the risks involved (superconducting magnets can be problematic — just ask CERN) and will greatly extend the useful life of the spectrometer (the liquid helium coolant would have boiled away within a few years of launch). Although the conventional electromagnet is only 1/5th as strong, its increased lifespan should allow for substantially more science to be conducted, especially considering the ISS's extended mission life. As the change is still underway, the impact to the final shuttle schedule is not fully known."
IAASIE (I am a space instrumentation engineer) and I really find such a major last minute decision hard to believe, seeing how long and detailed the flight model / integration tests are...
I wonder if this delay extends the set of contingencies (such as reboost, de-orbit, or repair) for the experimental unmanned space plane currently on orbit. The recent X37B liftoff was on a much lower inclination than the ISS's and "is designed to fly at altitudes between 110 and 500 nautical miles, or 126 to 575 statute miles" according to SpaceflightNow. This puts it within reach of Endeavor. The last time a supersecret bird went awry, they had to shoot it before it fell to keep it from raining hydrazine and beryllium on populated areas ... or so they said.
Obi-Wan: "I felt a great disturbance in the Force, as if millions of voices suddenly cried out in terror and were sudden
Just throwing a question out there: What's holding back the use of high critical-temperature superconductors in applications like the AMS magnet? Helium cooling is a vital, yet difficult and expensive proposition for many high-profile physics projects, to say nothing of innummerable NMR and MRI magnets out there. I realize that as ceramic-type substances, cuprate superconductors aren't as easily drawn into wire as the niobium alloys commonly used, but it seems like those technical challenges are worth dealing with in order to cool with liquid nitrogen rather than liquid helium. Particularly the superfluid helium that was planned for AMS- that stuff abhors a container. Is there some other physical limitation to cuprates that I'm missing, or is it just that the multi-decade nature of the big projects have kept them from adopting newer materials?
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
AMS is one of the poster children for a capability that will be lost with the retirement of the shuttle, a capability many insist we don't need - intact equipment return.
The original plan was, when the cryogens ran out, to return AMS to Earth and rerun the pre launch calibration checks (essentially using a particle accelerator to shoot particles through the AMS) - not only allowing us to learn about the effects of the orbital environment, but also being able to apply the knowledge of those effects to the analysis of the science data collected on orbit.
There was no reason to use a manned launcher to orbit the Hubble.
For the cost of the repair mission and all the other worthless manned flights they could have put up 10 Hubbles.
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If an object radiates away all its energy because it's in space, it doesn't get cold because space is cold. It gets cold because there's nothing there to radiate energy back into the object.
You can say that the stuff in space that isn't just empty space has a temperature, but it's so spread out that radiation becomes the dominant mode of heat transfer, and it has such little mass and is so cool that its black body radiation is meaningless. It is effectively not there for this interaction.
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