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1500 questions
22
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1 answer
How are hair and beard lengths maintained in space?
From the question What are the regulations governing (against) beards in space? we know that hair and beard length are not regulated on the ISS. For the most part pictures indicate both men and women keep their hair maintained.
I know when using…
James Jenkins
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How does a spacecraft know that it is in orbit?
After a 5 year long journey in space, Juno finally reached and started orbiting Jupiter. How does the probe actually know that it is in orbit, so that it can send confirmation message like 'Welcome to Jupiter!' ?
For the purposes of this question,…
A_D
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22
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2 answers
Nuances of the terms (mean / osculating / Keplerian / orbital) elements
I've been assuming that osculating, Keplerian, and orbital elements are all synonyms, with mean orbital elements just being these averaged over some time. However occasional comments make me suspect that there are some subtleties I'm missing. Could…
Voriki
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Is converting moon dust into oxygen a viable option for sustainability?
On the about page for Project Morpheus, the possibility of converting moon dust into oxygen is mentioned:
It was manufactured and assembled at JSC and Armadillo Aerospace. Morpheus is large enough to carry 1,100 pounds of cargo to the moon – for…
JohnB
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22
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Do Astronauts lose finger nails in space?
I recently heard that space suit gloves can cause Astronauts to lose their finger nails. We have an answer that includes a link to a 2010 article that says
in extreme cases, detach from their nailbeds or fall off entirely
The article is on a site…
James Jenkins
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22
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2 answers
How full is the geostationary belt?
The geostationary ring clearly seen in the above picture looks alarmingly crowded. How full is it? How much space does a satellite in that orbit require to operate safely? Surely, (other) geosynchronous orbits will also need to be taken into…
coleopterist
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22
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4 answers
Would a ball bounced in a centrifuge return to the floor?
In other words, does the centrifugal force inside a centrifuge only work to simulate gravity when an object is "attached" to the reference frame inside the centrifuge?
1G at sea level is normally about 9.8 m/s^2, correct?
However Centrifugal Force…
IT Bear
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21
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2 answers
How precise must be the antenna orientation to communicate with a deep space probe?
I guess that everyone is familiar with the problem of aligning a TV satellite dish: some degrees off and the signal you desire is gone.
How sensitive is communication with deep space probes to this problem? Is it addressed with special solutions or…
Federico
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Could the Soviets have rounded the Moon before Apollo? Why didn't they?
Neither the USSR nor Russia has ever sent a cosmonaut beyond low Earth orbit. In the 1960's it would've been very challenging for them to land a cosmonaut on the Moon, and their attempts were aborted. But didn't they have the ability to send a…
LocalFluff
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21
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1 answer
How could we observe the Oort cloud, if it exists?
The oort cloud has long been hypothesized as being around a light year away from the sun, but no observations have yet been made. Is it completely impractical with current science to make such an observation, or are there techniques we could try to…
berry120
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3 answers
Why do ion thrusters frequently use xenon as the reaction mass?
From skimming the Wikipedia article on ion thrusters, I notice that xenon is frequently (though not exclusively) used as the reaction mass in systems that have actually been deployed - Deep Space 1, Hayabusa, SMART-1, and Dawn, for example.
What are…
senshin
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21
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8 answers
Why isn’t the “JRTI” barge larger?
The barge that SpaceX's Falcon 9 was trying to land on is creatively called "Just Read The Instructions"(hereafter known as JRTI).
I've been told that SpaceX is using the barge to avoid a land based landing (aka a "landing") near a populated area…
Coomie
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21
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3 answers
What are the differences between a standard Merlin engine and the Merlin Vacuum engine?
I know that there's a difference between SpaceX's Falcon 9 1st stage engines and the 2nd stage engine, since that stage is specifically tuned for vacuum. Wikipedia also says that the Merlin Vacuum Engine is larger than the standard Merlin 1D. That…
Thane Brimhall
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Puncturing space suit during EVA. What would happen?
What would happen, if the space suit of a spacewalking crew was punctured during the extravehicular activity (EVA)? What are the chances of this happening? Has this already happened to anyone in the history of space exploration?
Jom
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7 answers
Can ion thrusters be scaled up?
All ion thrusters are quite small. Having read through the more approachable information about them, as they use physics pretty beyond me, I don't understand what it is about them that makes it necessary they be so small. Are they fundamentally…
kim holder
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