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131 votes
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Why destroy Juno at the end of the mission?

In order to assure that it cannot crash into Europa or other possible ocean moons and potentially contaminate them with Earth organisms. Juno is qualified to survive the radiation environment up to ...
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70 votes
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Why wasn't an RTG used on the Juno spacecraft?

That is precisely it. Plutonium-238, which is used in the creation of radioisotope thermoelectric generators (RTGs) is very difficult to come by. There are plenty of news articles on this, from ...
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64 votes
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Is Jupiter bright enough to be seen in color by the naked eye from Jupiter orbit?

The distance from Jupiter to the Sun is about 4.95 to 5.46 AU (Astronomical Unit, the distance of Earth to Sun). So the intensity of sunlight at Jupiter is about 1/25 of the intensity at Earth. This ...
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62 votes

Why destroy Juno at the end of the mission?

Why is it necessary to destroy the spacecraft? It's because life might well exist on some of Jupiter's moons. Despite the best efforts to assemble the spacecraft in extremely clean conditions, and ...
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55 votes
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Why are photos from Juno such low resolution?

Short answer: JunoCam is not a scientific instrument; It was put onboard solely to get some neat pictures. It is not necessary for the scientific mission, and is mostly there just for public interest....
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55 votes
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Why does this image of Jupiter look so strange?

As @Hobbes mentioned it is not an image of an entire hemisphere but it has been distorted to allow for wide angle vision. That's why it looks so strange. The image is a composite made by Kevin M. ...
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43 votes
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How does a spacecraft know that it is in orbit?

The Juno spacecraft has no means to directly measure and compute that it is in orbit. It did not send any such confirmation message. All it sent was an FSK tone indicating that it had completed the ...
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37 votes

Why wasn't an RTG used on the Juno spacecraft?

Another interesting note is that this mission more than any other mission to the outer solar system can use solar power. Why? Juno is in a polar orbit, and will continually be in the sun. Solar panels ...
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27 votes

Is Jupiter bright enough to be seen in color by the naked eye from Jupiter orbit?

Jupiter is very bright and is one of the brightest things in the night sky when it is visible. Through even a small telescope (such as my own 100mm telescope) shades of dark brown, beige, cream and ...
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22 votes
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Why does NASA's Juno spacecraft only have a one year primary mission?

While many missions have been able to continue beyond their design lifetimes (Cassini and the Mars Exploration Rovers being prominent examples), the type of mission and orbit Juno must undertake to ...
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21 votes

How does a spacecraft know that it is in orbit?

Using attitude determination devices, (including doppler shift of radio signal from Earth), it can determine* its location and velocity relative to Jupiter, and from that data, and knowing Jupiter ...
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20 votes

How long does it take for a signal to travel between Earth, and Juno at Jupiter?

Using NASA's Eyes measuring the distance from Jupiter to Earth at this moment (5th Jul 2016, 11:50 CEST) is 48 light minutes, 21.39 light seconds, and that would be the time Juno's communications ...
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18 votes
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How is JunoCam different from a normal CCD camera?

JunoCam used different technologies than does the typical framing camera one buys at a store. A typical digital color camera uses a Bayer filter pattern, a row of alternating tiny blue and green ...
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17 votes

How long does it take for a signal to travel between Earth, and Juno at Jupiter?

EDIT: based on @Beska's comment, I went back and calculated the difference including light time. In other words, you have to use Jupiter's position roughly 48 minutes ago to state the travel time. ...
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14 votes

Why wasn't an RTG used on the Juno spacecraft?

I had the opportunity to tour JPL a few months ago and asked this exact question to our tour guide. The solar panels on it are enormous and typically, spacecraft going beyond the asteroid belt are ...
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13 votes

Why destroy Juno at the end of the mission?

You can't re-purpose Juno after its mission as: Its instruments are designed for a specific mission profile, if you sent it elsewhere it wouldn't be able to produce good science. Its solar panels won'...
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13 votes
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Why does the Juno spacecraft flyby Earth on the way to Jupiter?

No, the Atlas 551 is not powerful enough to send Juno to Jupiter. From this article on NASA's website: The Juno spacecraft was launched from Kennedy Space Center in Florida on August 5, 2011. ...
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12 votes
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Will Juno record its deorbit?

You won't see Jupiter's atmosphere from the "inside". The entry and destruction of the vehicle is very fast, and occurs relatively high in the atmosphere. Way, way above any clouds. There would not be ...
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11 votes
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When can we (public) expect to see the first optical images of Jupiter from the Juno spacecraft?

There's an interesting Planetary Society article about this: What to expect from Junocam We won't be able to see spectacular views of Jupiter's belts and zones from Jupiter orbit until the very end ...
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9 votes

How was Juno's arrival set up to be on the evening of July 4th?

There have been four major US planetary probe events on (or scheduled for) 4th July. This compares to approximately a hundred "major events" for US planetary probes. At least one (Viking) was somewhat ...
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9 votes

Juno to Jupiter Budget

Was that option considered in detail? Almost certainly not. This question is based on the false assumption that staffing levels remain more or less constant across all phases of flight. This is not ...
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9 votes
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Is there any publicly available logging, or "Wayback Machine" for DSN Now activity?

I have been looking into this as well. As I have been told by one NASA employee, there is no easy way to get old data, but there is a way if you're willing to go through lots of data. NASA saves old <...
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9 votes

Why wasn't an RTG used on the Juno spacecraft?

Phiteros' answer states the fact that plutonium is in scarce supply and PearsonArtPhoto's answer points out that Juno's mission profile allows it to use solar panels. These issues are legitimate and (...
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9 votes

The plane of the orbit of Juno around Jupiter is not the ecliptic plane. How did it get into this plane?

The plane of the orbit around the Sun is not directly related to the planet-relative plane of the hyperbola on approach to Jupiter, or correspondingly the orbit around Jupiter after orbit insertion. ...
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9 votes
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Who built Juno's chipsets?

BAE Systems is one supplier for the command and data handling processor. https://en.wikipedia.org/wiki/RAD750 The RAD750 is a radiation-hardened single board computer manufactured by BAE Systems ...
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9 votes

Does NASA use Newtonian model of gravity for plotting the course of Juno or general relativity?

Not only does it use Einstein's Theory of Relativity, it's actually going to use Jupiter's huge mass to do a test that hasn't been done yet, on how it affects rotating objects. As it's expected to ...
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9 votes
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Why does Juno use "mixed oxides of nitrogen" oxidizer for propulsion? Which ones?

MON according to Wikipedia: Mixed oxides of nitrogen (MON) are solutions of nitric oxide (NO) in dinitrogen tetroxide/nitrogen dioxide (N2O4 and NO2). The addition of a small amount of nitric ...
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8 votes
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Juno Mission. How better resolution will the optical images be to previous missions?

Juno-cam is designed to achieve about 15km/pixel resolution, at 4300 km, and proportionately less at greater distance. At closest approach it may achieve 3km/pixel This compares with Galileo that ...
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8 votes

How does a spacecraft know that it is in orbit?

First a clarification. If one insists that "knowing" requires self awareness and intelligence, then the Juno spacecraft of course doesn't "know" anything. Rather than getting hung up on the silliness ...
8 votes
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When will Juno send us some pictures from it's tight orbit?

http://www.planetary.org/blogs/emily-lakdawalla/2016/06090600-what-to-expect-from-junocam.html The first major day for pictures should be August 27th, but image release shouldn't start occurring ...
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