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OneWeb successfully launches 34 more satellites into orbit
- dmitrygr 7y agobetween this and Elon's stuff, how long till it is impossible to do astronomy or safely launch anything into space?
- kilroy123 7y agoIdeally with space based telescopes. Hopefully launching things up into orbit becomes dirty cheap and it's not so unreasonable.
- aruggirello 7y agoThese satellites are going to damage real science that is already costing us billions (and what's more perverse, do it for a profit). Professional astronomers already warned us about the issue, and IMHO there's no reason to think we know better. Of course we're launching telescopes into space (like the James Webb, planned for 2021 [1]), but those won't be able to replace science done by the larger terrestrial telescopes. For reference, the ELT, which is currently being built in Chile, will be 74 meters high, 86 meters wide (with a Ø 39.3 meters primary mirror), and weighing 5,000 tonnes. [0] https://en.wikipedia.org/wiki/European_Extremely_Large_Telescope https://en.wikipedia.org/wiki/European_Extremely_Large_Teles... [1] https://en.wikipedia.org/wiki/James_Webb_Space_Telescope https://en.wikipedia.org/wiki/James_Webb_Space_Telescope
- bouncycastle 7y agoSurely someone who builds an 86 meter wide telescope is able to spend a few bucks on image processing software, that even today's hand held mobile devices could do in real time...
- dmurray 7y agoMost astronomy is done with computers. It should be easy for a computer to ignore or subtract all known satellites. If you only get 900 exposures of some new comet instead of 1000, that's still plenty. And we'd need many orders of magnitude more satellites to make 10% of astronomical photos unusable. I hear the astronomy argument all the time, but I just don't believe it. If satellites are ever cheap and plentiful enough to make that kind of difference, the astronomers can launch a thousand Hubble-style space telescopes and timeshare on those.
- stareatgoats 7y agoI believe GP was talking about the ever growing space debris. https://www.esa.int/Safety_Security/Space_Debris/Space_debris_by_the_numbers https://www.esa.int/Safety_Security/Space_Debris/Space_debri...
- Mountain_Skies 7y agoThese satellites should be in low enough orbits that any junk from them burns up in the atmosphere as their orbits decay. Maybe there could be an issue from collisions in low orbit pushing objects into higher orbits but those likely would be erratic orbits with low points that still subject it to decay.
- deleted 7y ago[deleted]
- greglindahl 7y agoOneWeb's constellation is high enough that it'll take a lot more than 25 years for any satellite that fails to deorbit itself to decay. On the way down, these debris will cross the ISS orbit and the most popular sun-synchronous orbits. Starlink is lower, but still above the ISS and the SSO at 282km.
- henrikeh 7y agoAll astronomy can’t be done from space. Space has many issues such as maintainability, heat, reflector sizes and the list goes on. I have friends and former colleagues who do astronomy. I’ll trust the experts who’s profession are actually impacted.
- monk_e_boy 7y agoThey are mostly a problem at sunrise and sunset when they catch the sun and reflect it. Astronomy isn't much good then anyway.
- monk_e_boy 7y agoHow am I getting downvoted? How can satellites reflect the sun when they are in shadow? And who is pointing their telescope up at sunrise? No one!
- 34679 7y agoIf you spread 50,000 cars over the surface of the planet, how much of the Earth's surface do you think would be blocked from view by the ISS? Because we have millions of cars scattered all across the Earth and from space, you can't even tell they're there. >how long I'd say at least until there are more satellites than cars. In other words, not gonna happen.
- _Microft 7y agoThis is a poor comparison. The contrast of a cars to the background of Earth is low, ofcourse we can not see any. Remove Earth and let these cars fly on orbits 500km below ISS and, oh boy, would you suddenly see car roofs and windows glinting in the dark everywhere. Amazing for satellite watchers and annoying for astronomers were e.g. Iridium flares. See [0][1]. Worst case for Iridium flares was them being about 50x as bright as planet Venus. Starlink satellites have the advantage of orbiting far lower which puts them into Earth's shadow on part of their orbits. Around midsummer, though, satellites in an orbit at 550km, like Starlink's lowest shells, will be lit by sunlight as soon as they cross northwards over ~ 45° latitude (their orbits have an inclination of 53°, so they definitely do this). I'm going out on a limb here but they might interfere with infrared observations because of emitted heat (being exposed to bright sunlight every half orbit heats them up). Parent poster was most likely also referring to the Kessler Syndrome [2] when talking about safety. [0] https://youtu.be/MTGVuPr9Epg?t=100 https://youtu.be/MTGVuPr9Epg?t=100 [1] https://en.wikipedia.org/wiki/Satellite_flare#Iridium_flares https://en.wikipedia.org/wiki/Satellite_flare#Iridium_flares [2] https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome
- 34679 7y agoWhat percentage of the sky do you envision will be occupied by man made objects?
- Veedrac 7y agoVery small, but that's not a useful measure. For astronomy, remember that bright, fast-moving objects will leave sizable streaks in images that halo a lot[1]. OTOH, intensity varies with time and satellite height. With regards to how much space we have, note that a satellite is taking up an orbit, not a point, and it's a lot harder to fit things in those safely, since they have a tendency to overlap. [1]: https://nationalastro.org/news/starlink-satellites-imaged-from-ctio/ https://nationalastro.org/news/starlink-satellites-imaged-fr...
- mrfusion 7y agoHow long until the most remote and poorest populations in the world can access jobs and the worlds collective knowledge on the internet? That’s a much better question to ask, mr negative.
- ksrm 7y agoMost of these people already have at least 2G cellular coverage.
- mrfusion 7y agoSpreading FUD. Spacex has the most advanced satellite management and deorbiting systems ever made. Fully approved by the fcc.
- ceejayoz 7y agoThat accounts for access to space. Like it or not, there are astronomers pretty pissed off about Starlink & co. https://twitter.com/superasassn https://twitter.com/superasassn has been pretty open about it, for example. https://twitter.com/89Marvaz/status/1196356715270291456 https://twitter.com/89Marvaz/status/1196356715270291456 as well.
- aivisol 7y agoDo you have any details about this? As an amateur astronomer I am concerned about increased number of objects in orbit and their eventual fate. How the quality of deorbiting system measured? Have they deorbited any yet and their success rate is higher than others? Also I had no idea FCC approves satellite guidance systems, I thought they mostly supervise radio spectrum.
- greglindahl 7y agoEvery country is supposed to regulate space debris, and in the US, that happens to have been assigned to the FCC. BTW, many people in the industry thinks that the international standard of 25 years needs to be strengthened.
- mrfusion 7y agoI came across this. Someone tried to put the facts together from original sources. If you read the links report back. I’d be curious what your opinions are. https://pay.reddit.com/r/spacex/comments/fc9rqq/rspacex_discusses_march_2020_66/fl8rp8g/ https://pay.reddit.com/r/spacex/comments/fc9rqq/rspacex_disc...
- pietroq 7y agoLet's put this to rest for once and all. The average radius of Earth is 6,371 km. Initial sats will be at 550 km height (many will be higher, many somewhat lower, but does not make much diff.) So the surface of the 6,931km radius globe is ~603,672,875 km2 (~604 million square kilometers). Don't have exact size for a Starlink sat, but a good upper bound is 3 x 2 m, i.e. 6 m2 = 0.000006 km2. Let's say there will be 40,000 such sats at peak, so altogether they occupy 0.24 km2 area. Altogether, they will occupy 0.00000003976% of the sky. QED.
- ourlordcaffeine 7y agoLooks like you've never done astronomy. A single satellite passing through the shot can saturate the sensor and ruin a multi hour exposure.
- zaroth 7y agoThe satellite would not be passing through the shot for the entire exposure. If you had software to detect and delete frames with a satellite moving through them, how many frames from a multi-hour exposure would have to be deleted? I assume it can even be done digitally in post-production, but even if you had to actually close the aperture ahead of the satellite crossing through your frame, we know exactly where the satellites are going to be so we could calculate when they would enter and exit the frame.
- greglindahl 7y agoWe studied this technique in the graduate-level observation class I took 30 years ago. It is not trivial for a lot of reasons, especially for modern wide-field telescopes with multiple satellites in the field of view at all times.
- zaroth 7y agoI appreciate the expert feedback. A lot of very complex things often seem trivial from an outside perspective. I think everyone can agree this will be at least somewhat a burden on astronomy and will at least marginally increase the cost in obtaining certain imagery. I guess it’s possible that there are certain types of images which may even become prohibitive or impossible to obtain, but I personally haven’t read a scientific analysis making this claim. I also think most everyone is agreeing that we attack this problem from both sides. Limit the reflectivity of the satellites and work on enhancing software to mitigate the effects. In the end there is a tremendous benefit to society both from astronomy as well as having affordable worldwide broadband internet. I’m not going to go so far to say that we need to sacrifice one for the other, but I think the capabilities and opportunities provided by Starlink to billions of people are too great to pass up. Even if there is a significantly increased cost to perform certain observations. Even if it means some observations can only be made from orbit in the future. Even if some observations become entirely impossible? Hopefully that can be avoided.
- jws 7y agoI propose: LEO satellites are not a problem for astronomy. • Atmosphere distorts observations. • Astronomers do not like distortion. • Astronomers like dark backgrounds. • For a satellite to be illuminated, it must be visible to the sun. a - - - - - b/ \ | E| SUN \ / - - - - - Here is the Earth (E), the Sun, and two satellites in low earth orbit, a and b. The dashed lines are the earth’s shadow. LEO satellites are really low, like 1/20th of a diameter of the earth. That means that in order to be illuminated in a night sky, they have to be on the dark side of the Earth (left of center here), but not so far that they have dipped into the shadow. “a” is in position for that, but “b” is not. Illuminated, dark side satellites are all in a band around the Earth at the twilight line. Astronomers don’t like lit skies, so they wait until local dark. Once you get to local dark, the twilight lit satellites are off toward the horizon where you don’t want to observe because there is a huge pile of atmosphere. If you are making a cool picture of Orion rising out of a desert lake, well, yeah, you may need to edit out some satellites depending on the time of year, but astronomers can do their job just fine.
- benbristow 7y agoWhen will this be available to the general public? I've heard of so many different "internet from space/the sky" schemes from Google Loon to SpaceX to this but I've never once been able to connect to a node to give it a whirl. I'm sure it's a difficult technical challenge but it does seem to be taking a long time!
- dforrestwilson 7y agoLikely never. OneWeb is about to go bankrupt. Launching is a way for SoftBank to still claim spectrum rights.
- _Microft 7y agoGP might want to look here: https://www.bloomberg.com/news/articles/2020-03-19/softbank-s-oneweb-is-said-to-mull-bankruptcy-as-cash-dwindles https://www.bloomberg.com/news/articles/2020-03-19/softbank-...
- axaxs 7y agoAs an additional data point, I live in the area and they just furloughed a lot of employees last week. Not sure the exact percentage, though.
- Veedrac 7y agoStarlink has launched 360 satellites, and they originally wanted to start limited service after launching 420 sats, so we're possibly only months away from them starting service if things go well.
- scandum 7y agoOneWeb will be worse than fiberoptics while Starlink will be better than fiberoptics. This suggests OneWeb is pretty much doomed to fail.
- new_realist 7y agoThere’s no way Starlink will be better than fiber. You have to pay a 25 ms penalty just to play, and then you have the cost of each hop, of which there are many.
- eutropia 7y agoMusk is selling precisely that to NYSE-London traders. Speed of light in a vacuum is considerably (I think 40%) faster than speed of light in glass fiber optics
- new_realist 7y agoLike I said, there is a latency barrier to get in and out of the atmosphere due to RF modulation. Only NYC to Tokyo will be close, but that’s generous, as it doesn’t take into account intersatellite routing delays. Whereas, NYC to London by fiber is a single hop.
- new_realist 7y agoFurther, note that Starlink’s current batch of satellites don’t have laser links, so data can’t hop from satellite to satellite. It’s up and then back down immediately. We’ll have to wait for v2 or v3.
- cagenut 7y agohighly recommend you watch these two latency modelings: https://www.youtube.com/watch?v=QEIUdMiColU https://www.youtube.com/watch?v=QEIUdMiColU https://www.youtube.com/watch?v=m05abdGSOxY https://www.youtube.com/watch?v=m05abdGSOxY
- new_realist 7y ago
- dreamlayers 7y agoOn Saturday March 21st I was at the tip of Canada's Point Pelee National Park, approximately 41.909055, -82.509154. At 9:12 EDT (1:12 AM UTC on the next day), I saw a an approximate disordered line of satellites passing above Orion. They were all going at the same speed and in a very similar direction, west to east close to parallel with the belt of Orion. But they were all on slightly different almost parallel tracks. The spacing was more regular, though also a bit irregular.
- greglindahl 7y agoThere are a couple of websites out there that give you future and past locations of "Starlink trains", which is what you probably saw. This site https://findstarlink.com/ https://findstarlink.com/ does arbitrary locations but not times in the past. As does this one https://james.darpinian.com/satellites/?special=starlink https://james.darpinian.com/satellites/?special=starlink ... presumably if you looked around a bit more than I just did you could find one that does historical viewings.
- chkaloon 7y agoI just spent a week at a remote Alaska village 120 miles from Nome to help with the Iditarod. The villages there rely on rural broadband, which is essentially a single satellite-fed community receiver which pushes signal out to access points at each house. Very expensive, slow, high latency, and nasty data caps. It will be interesting to see how these efforts change that monopoly and as a result those communities.
- greglindahl 7y agoGood news, there are several satellite constellations on the way to break that monopoly, including some small ones that just address Alaska.