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James Kerman
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Posts posted by James Kerman
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Welcome to the forum, @johnmorris.
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2 minutes ago, panzerknoef said:
Banned for making a sentence longer than 2 words.
Autobanned.
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Photos or it didn't happen.
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For a rendezvous I will usually get my inclination to 0.1° for a 'medium gravity' body like the Mun. This will help you later on and is good practice for when you begin docking.
I make either Pe or Ap the same as my target and wait for the target to ensure a close encounter - in your example you will be at least 3.4km away from an intercept without adjustment. Once I'm within 50 - 80km of my target I set a maneuver node at the point I matched either the Ap or Pe and play around until I get the intersect within 1km (if you have matched planes you will only need to burn either prograde or retrograde to fine tune the encounter). With a fairly close orbit like yours the speed of the encounter should be around 20-30m/s but even if its higher, remember that a Kerbal EVA pack has about 500m/s Dv (quite a lot for orbital maneuvers).
Once you are within 2.2km of your target, switch to it using the [ key and EVA your stranded Kerbal. At this point I look for the rescue vehicle and 'select as target'. From here on it's all about the nav ball so switch it into target mode if it isn't already. You should see a target
or anti-target 
symbol in addition to the standard vector symbols. All you need to do is match up the target symbol with your prograde symbol 
and you are now headed towards the rescue vessel at the speed indicated on the top of the navball. You will need to make some small adjustments and then slow your Kerbal down when you get really close.
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Welcome to the forum @Galane. Pistachios are probably not the only nuts called Kerman.
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6 minutes ago, kerbiloid said:
I never argued that they had some rafts or primitive boats.
My mistake, apologies.
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20 minutes ago, MPDerksen said:
Is there a repository, thread or other resource that shows examples of some various craft?
Most of us use https://kerbalx.com/. It's a really well thought out site where most of the membership shares vessels.
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Welcome to the forum, @Scorpion14.
If you have the steam install you can try verifying the integrity of the game online:
Quote- Restart your computer and launch Steam
- From the Library section, right-click on the game and select Properties from the menu.
- Select the Local files tab and click the Verify integrity of game files... button.
- Steam will verify the game's files - this process may take several minutes.
https://support.steampowered.com/kb_article.php?ref=2037-QEUH-3335
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Welcome to you too, @colonoscopy.
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17 minutes ago, MPDerksen said:
don't I need to time it so that when I've crossed that distance, Minmus will be there?
Just to expand on @5thHorseman's advice - The higher altitude your Ap, the slower you are going so your vessel will linger for quite a while in relatively the same spot, behind Minmus, making an encounter easier.
I like to enter the sphere of influence of minmus after Kerbin apoapsis (on the way back down to kerbin) so that I can course correct at Ap. A little trick I use when performing a course correction here is to lower my engine thrust (right click on engine, reduce bar on the thrust limiter). This is a useful method whenever you want to make fine corrections.
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4 minutes ago, MPDerksen said:
Please explain what you mean by this.
When you have your vessel in low Kerbin orbit, go to map view and click on Minmus and select as target. You should see two dotted lines to minmus An (ascending node) or Dn (descending). These are the two points in your current orbit that intersect the orbital plane of minmus. If you burn for the moon at these points you should be able to intersect Minmus without a inclination burn.
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I always burn for minmus on either the ascending or descending node. You will probably need to make your apoapsis higher than minmus and you should get an intercept. It costs about 930 Dv. When you are at kerbin AP correct your inclination (your velocity will be at its lowest and that is when an inclination burn is cheapest).
As for rescue missions (in career) I use a basic pod/hitchhiker/heatshield arrangement that also fulfills the 5 man station contract requirement and either use the extra seats to level up crew or I loiter in the area to collect more stranded kerbals.
My method of landing (not the most efficient) is a burn to kill most of the velocity a little earlier than a suicide burn then, at about 100m and 20-30ms, I tap shift until speed slowly decreases or X if I slow down too fast. I usually land under 1ms. One thing to remember is that if you are holding retrograde the SAS resets to stability assist under 1ms.
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8 hours ago, kerbiloid said:
I'm not sure if the Native Australians had canoe 20ky (or how much) years ago.
Probably far earlier than that. It is accepted by historians that prehistoric humans must have used canoes to migrate from Sunda (now Southeast Asia) to Sahul (New Guinea and Australia) about 40,000–50,000 years ago.
QuoteThe oldest inferred watercraft of 44,000-50,000 years ago, was sufficient to bring numerous ‘immigrants’ to Sahul, but was presumably not capable of supporting colonisation of the Pacific Islands at that time. Those early settlers travelled on land and probably by coastal navigation to occupy the entire Sahul landmass in a relatively short time. By 40,000 years ago the main parts of this land were occupied and a little later Tasmania (then part of the mainland). The Solomon Islands and Buka Island, some 180km distant from the then occupied New Ireland and New Britain, were reached about 30,000 years ago. This was nearly three times the distance of the initial crossing from Sunda to Sahul. The new island communities must have retained, and in time replaced, their boats as it was vital to keep the connection with other people for the long term viability of the islands’ populations.
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Further reading has led me to think a possible explanation is the beginnings of something like the Laschamp event. How effective would 5% of the magnetosphere be at blocking solar and cosmic radiation?
QuoteThe Laschamp event was a short reversal of the Earth's magnetic field. It occurred 41,400 (±2,000) years ago during the last ice age and was first recognised in the late 1960s as a geomagnetic reversal recorded in the Laschamp lava flows in the Clermont-Ferrand district of France.[1] The magnetic excursion has since been demonstrated in geological archives from many parts of the world. The period of reversed magnetic field was approximately 440 years, with the transition from the normal field lasting approximately 250 years. The reversed field was 75% weaker, whereas the strength dropped to only 5% of the current strength during the transition. This reduction in geomagnetic field strength resulted in more cosmic rays reaching the Earth, causing greater production of the cosmogenic isotopes beryllium 10 and carbon 14.[2] The Laschamp event was the first known geomagnetic excursion and remains the most thoroughly studied among the known geomagnetic excursions.[3]
I have found some data (from 2009) showing the strength of the magnetosphere over time.
Image Credit: U.S. Geological Survey -
The World Magnetic Model will be updated on 30th January 2019 due to magnetic north shifting away from Canada and towards Siberia. The most current model from 2015 was expected to be accurate until 2020 however researchers are making an unprecedented early change to account for this shift.
Image Credit: World Data Center for Geomagnetism/Kyoto Univ.QuoteUpdate, 9 January: The release of the World Magnetic Model has been postponed to 30 January due to the ongoing US government shutdown.
Something strange is going on at the top of the world. Earth’s north magnetic pole has been skittering away from Canada and towards Siberia, driven by liquid iron sloshing within the planet’s core. The magnetic pole is moving so quickly that it has forced the world’s geomagnetism experts into a rare move.
On 15 January, they are set to update the World Magnetic Model, which describes the planet’s magnetic field and underlies all modern navigation, from the systems that steer ships at sea to Google Maps on smartphones.
The most recent version of the model came out in 2015 and was supposed to last until 2020 — but the magnetic field is changing so rapidly that researchers have to fix the model now. “The error is increasing all the time,” says Arnaud Chulliat, a geomagnetist at the University of Colorado Boulder and the National Oceanic and Atmospheric Administration’s (NOAA’s) National Centers for Environmental Information.
The problem lies partly with the moving pole and partly with other shifts deep within the planet. Liquid churning in Earth’s core generates most of the magnetic field, which varies over time as the deep flows change. In 2016, for instance, part of the magnetic field temporarily accelerated deep under northern South America and the eastern Pacific Ocean. Satellites such as the European Space Agency’s Swarm mission tracked the shift.
By early 2018, the World Magnetic Model was in trouble. Researchers from NOAA and the British Geological Survey in Edinburgh had been doing their annual check of how well the model was capturing all the variations in Earth’s magnetic field. They realized that it was so inaccurate that it was about to exceed the acceptable limit for navigational errors.
Wandering pole
“That was an interesting situation we found ourselves in,” says Chulliat. “What’s happening?” The answer is twofold, he reported last month at a meeting of the American Geophysical Union in Washington DC.
First, that 2016 geomagnetic pulse beneath South America came at the worst possible time, just after the 2015 update to the World Magnetic Model. This meant that the magnetic field had lurched just after the latest update, in ways that planners had not anticipated.
Second, the motion of the north magnetic pole made the problem worse. The pole wanders in unpredictable ways that have fascinated explorers and scientists since James Clark Ross first measured it in 1831 in the Canadian Arctic. In the mid-1990s it picked up speed, from around 15 kilometres per year to around 55 kilometres per year. By 2001, it had entered the Arctic Ocean — where, in 2007, a team including Chulliat landed an aeroplane on the sea ice in an attempt to locate the pole.
In 2018, the pole crossed the International Date Line into the Eastern Hemisphere. It is currently making a beeline for Siberia.
The geometry of Earth’s magnetic field magnifies the model’s errors in places where the field is changing quickly, such as the North Pole. “The fact that the pole is going fast makes this region more prone to large errors,” says Chulliat.
To fix the World Magnetic Model, he and his colleagues fed it three years of recent data, which included the 2016 geomagnetic pulse. The new version should remain accurate, he says, until the next regularly scheduled update in 2020.
Core questions
In the meantime, scientists are working to understand why the magnetic field is changing so dramatically. Geomagnetic pulses, like the one that happened in 2016, might be traced back to ‘hydromagnetic’ waves arising from deep in the core1. And the fast motion of the north magnetic pole could be linked to a high-speed jet of liquid iron beneath Canada2.
The jet seems to be smearing out and weakening the magnetic field beneath Canada, Phil Livermore, a geomagnetist at the University of Leeds, UK, said at the American Geophysical Union meeting. And that means that Canada is essentially losing a magnetic tug-of-war with Siberia.
“The location of the north magnetic pole appears to be governed by two large-scale patches of magnetic field, one beneath Canada and one beneath Siberia,” Livermore says. “The Siberian patch is winning the competition.”
Which means that the world’s geomagnetists will have a lot to keep them busy for the foreseeable future.
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Welcome to the forum, @SamTheShark. Congratulations on your first landing.
The good news is that a vessel that can land and return from the moon is more than capable of doing the same on Minmus.
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2 hours ago, Nuke said:
i have to say i liked the original title better.
Sorry about that, Mate, It was just a little "tounge in cheek" humor however I changed it because I got to thinking someone might post a video and I don't want to encourage that.
The Australian Broadcasting Corporation has released some scientific commentary about The Cow (I believe from the 233rd meeting of the American Astronomical Society in Seattle):
QuoteDr Raffaella Margutti of Northwestern University in Chicago and Her team (responsible for the image above) were also following the Cow, using 16 telescopes around the world to study radio waves, gamma rays, and a spectrum not usually used to study supernovae: hard X-rays, which are 10 times more powerful than normal X-rays. Unlike a regular supernova, the Cow has very little material swirling around it, which it enabled the team to peer straight into its heart.
"The most striking feature in the Cow is what we find in the hard X-rays," Dr Margutti said. These powerful X-rays indicated that lying deep within the core of the Cow was a central engine that continued to pump out energy for at least 100 days after the blast. This kind of long-lasting energy source is not known in normal supernovae or gamma rays, but could occur as material swirls around a compact object such as a newly forming black hole or fast-spinning magnetar. "The big question we're trying to find out is why in the first place we have a little amount of mass." Dr Margutti said the blast could have been created by the death of a massive blue supergiant star, many times the mass of the Sun."They should explode, but we don't see them," Dr Margutti said. "There is a possibility that those types of stars just go directly into a collapse without producing even a little bit of an explosion."Dr Margutti said the radio data indicated the Cow was not created by a pre-existing black hole stripping a star.Dr Tara Murphy and her PhD student Dougal Dobie of the University of Sydney used the CSIRO's Australia Telescope Compact Array at Narrabri in New South Wales to observe radio emissions created by the blast's shockwave. "What we can see is that the shockwaves were travelling about a 10th the speed of light and we saw the brightness of this source in radio keep increasing over time," Dr Murphy said.
The increasing brightness was also observed in shorter wavelengths by team leader and Caltech astronomer Anna Ho and her colleagues, using telescopes in Hawaii and Chile. "The fact it was getting brighter with time and particularly in higher frequencies shows there must be something that was still powering the explosion pumping energy into this material," Dr Murphy said. "It wasn't just this explosion that happened and then was fading away, there must be something that was still there that makes it different from the typical supernova we see." She said the radio data pointed to the presence of a magnetar at the core of the supernova.
Whatever it is, it does not fit any of the models, said Dr Daniel Perley, an astronomer from Liverpool John Moores University in the UK who led another of the international teams. "It has very different properties from anything we've seen before," Dr Perley said. When word got out that a strangely bright object had been spotted in our cosmic neighbourhood by the ATLAS telescopes on June 16, astronomers scrambled to observe its rise and fall using a global network of telescopes. "It may well be the most intensely observed astronomical source ever," Dr Perley said. "The only thing that competes would be the gravitational wave detection from a year-and-a-half ago," he said, referring to the observation of fireworks created by the collision of two ancient stars. Dr Perley and his team used optical telescopes to follow the Cow every night for more than a month. The focus now is to find more objects like the Cow to definitely work out how they were formed, Dr Perley said. "This shouldn't be one of a kind," he said. "There were some events that had similar properties that were seen in previous surveys, but no-one really recognised them ... and they were never followed up in real time or even discovered in real time. "So, now we know what to look for, we're pushing forward to find more and to get more data."
Dr Brad Tucker, of the Australian National University, did not study the Cow but has investigated supernova events detected by Kepler and now, the TESS telescope. Of all the hypotheses put forward by the teams, he leans towards the creation of a black hole by a failed supernova. "I don't know if the data favours this one way or the other. But the reason I like that is it's simple — it doesn't require any special physical mechanism. "We know that black holes exist, but we've never been able to pinpoint the birth of a black hole. "We know blue supergiants exist and explode. We know they explode at different regimes. What's not to say that this could create a black hole? "Every time we see a blue supergiant, something is weird about it." Less likely, he thought, was the idea of a tidal disruption event. "If it's not a supernova we always say, 'Is this a tidal disruption event?' and you take a look at it and generally the answer is 'no'," Dr Tucker said. "But again, these are things we're just finding more and more of and just trying to understand. "We're narrowing down and ruling things out, but what we can definitively say is there is another type of explosion or type of star that goes bang in the night that we're just starting to uncover."
https://www.abc.net.au/news/science/2019-01-11/cow-cosmic-blast-supernova-black-hole-magnetar/10703320 *Quotes have been reorganized.
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On June 16th 2018 the Asteroid Terrestrial-impact Last Alert System telescope in Hawaii detected a flash of light at least 10 times brighter than a typical supernova. The event was dubbed AT2018cow and has been puzzling astronomers for the past 6 months.
Image Credit: https://www.northwestern.edu/
QuoteSo exactly what is the Cow? Using data from multiple NASA missions, including the Neil Gehrels Swift Observatory and the Nuclear Spectroscopic Telescope Array (NuSTAR), two groups are publishing papers that provide possible explanations for the Cow's origins. One paper argues that the Cow is a monster black hole shredding a passing star. The second paper hypothesizes that it is a supernova - a stellar explosion - that gave birth to a black hole or a neutron star.
Researchers from both teams shared their interpretations at a panel discussion on Thursday, Jan. 10, at the 233rd American Astronomical Society meeting in Seattle.
A Black Hole Shredding a Compact Star?
One potential explanation of the Cow is that a star has been ripped apart in what astronomers call a "tidal disruption event." Just as the Moon's gravity causes Earth's oceans to bulge, creating tides, a black hole has a similar but more powerful effect on an approaching star, ultimately breaking it apart into a stream of gas. The tail of the gas stream is flung out of the system, but the leading edge swings back around the black hole, collides with itself and creates an elliptical cloud of material. According to one research team using data spanning from infrared radiation to gamma rays from Swift and other observatories, this transformation best explains the Cow's behavior.
"We've never seen anything exactly like the Cow, which is very exciting," said Amy Lien, an assistant research scientist at the University of Maryland, Baltimore County and NASA's Goddard Space Flight Center in Greenbelt, Maryland. "We think a tidal disruption created the quick, really unusual burst of light at the beginning of the event and best explains Swift's multiwavelength observations as it faded over the next few months."
Lien and her colleagues think the shredded star was a white dwarf - a hot, roughly Earth-sized stellar remnant marking the final state of stars like our Sun. They also calculated that the black hole's mass ranges from 100,000 to 1 million times the Sun's, almost as large as the central black hole of its host galaxy. It's unusual to see black holes of this scale outside the center of a galaxy, but it's possible the Cow occurred in a nearby satellite galaxy or a globular star cluster whose older stellar populations could have a higher proportion of white dwarfs than average galaxies.
A paper describing the findings, co-authored by Lien, will appear in a future edition of the journal Monthly Notices of the Royal Astronomical Society.
"The Cow produced a large cloud of debris in a very short time," said lead author Paul Kuin, an astrophysicist at University College London (UCL). "Shredding a bigger star to produce a cloud like this would take a bigger black hole, result in a slower brightness increase and take longer for the debris to be consumed."
Or a New View of a Supernova?
A different team of scientists was able to gather data on the Cow over an even broader range of wavelengths, spanning from radio waves to gamma rays. Based on those observations, the team suggests that a supernova could be the source of the Cow. When a massive star dies, it explodes as a supernova and leaves behind either a black hole or an incredibly dense object called a neutron star. The Cow could represent the birth of one of these stellar remnants.
"We saw features in the Cow that we have never seen before in a transient, or rapidly changing, object," said Raffaella Margutti, an astrophysicist at Northwestern University in Evanston, Illinois, and lead author of a study about the Cow to be published in The Astrophysical Journal. "Our team used high-energy X-ray data to show that the Cow has characteristics similar to a compact body like a black hole or neutron star consuming material. But based on what we saw in other wavelengths, we think this was a special case and that we may have observed - for the first time - the creation of a compact body in real time."
Margutti's team analyzed data from multiple observatories, including NASA's NuSTAR, ESA's (the European Space Agency's) XMM-Newton and INTEGRAL satellites, and the National Science Foundation's Very Large Array. The team proposes that the bright optical and ultraviolet flash from the Cow signaled a supernova and that the X-ray emissions that followed shortly after the outburst arose from gas radiating energy as it fell onto a compact object.
Typically, a supernova's expanding debris cloud blocks any light from the compact object at the center of the blast. Because of the X-ray emissions, Margutti and her colleagues suggest the original star in this scenario may have been relatively low in mass, producing a comparatively thinner debris cloud through which X-rays from the central source could escape.
"If we're seeing the birth of a compact object in real time, this could be the start of a new chapter in our understanding of stellar evolution," said Brian Grefenstette, a NuSTAR instrument scientist at Caltech and a co-author of Margutti's paper. "We looked at this object with many different observatories, and of course the more windows you open onto an object, the more you can learn about it. But, as we're seeing with the Cow, that doesn't necessarily mean the solution will be simple."
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Welcome back to the forum and the game @Puddle Jumper.
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Juno has captured images of a volcanic plume on IO.
Image credits: Southwest Research Institute
QuoteLight from the plumes and fires of Io on Earth’s darkest night
Dec. 31, 2018 — A team of space scientists has captured new images of a volcanic plume on Jupiter’s moon Io during the Juno mission’s 17th flyby of the gas giant. On Dec. 21, during winter solstice, four of Juno’s cameras captured images of the Jovian moon Io, the most volcanic body in our solar system. JunoCam, the Stellar Reference Unit (SRU), the Jovian Infrared Auroral Mapper (JIRAM) and the Ultraviolet Imaging Spectrograph (UVS) observed Io for over an hour, providing a glimpse of the moon’s polar regions as well as evidence of an active eruption.
https://www.swri.org/press-release/light-from-volcanoes-io-juno-jupiter-moon
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8 hours ago, ThatGuyWithALongUsername said:
the dark side of the Moon
I blame Pink Floyd (great album, unfortunate title).
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31 minutes ago, Fluffy crocodile said:
So i have a contract that wants me to transefrr crew between vessels near kerbin. I have transfered crew in soace near kerbin but it does not work. Any help?
The transfer needs to happen between 2 different vessels and requires an orbital rendezvous. The easiest way is to rescue a kerbal from orbit (you will only have to launch 1 rocket).
This illustrated guide really helped me with RV and docking:
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Welcome back, Mate.
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11 hours ago, GRS said:
Yeah whatever, i dont see any Indonesia subforum, and i dont know what to do.
Welcome to the forum, Mate.
You could try posting here:
or anti-target 
symbol in addition to the standard vector symbols. All you need to do is match up the target symbol 
and you are now headed towards the rescue vessel at the speed indicated on the top of the navball. You will need to make some small adjustments and then slow your Kerbal down when you get really close.
Hayabusa 2 on its way back to earth
in Science & Spaceflight
Posted
Division F (Planetary Systems and Bioastronomy) of the International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (hereafter IAU WG) has begun naming features on Ryugu: