Thursday Throughput for June 6, 2019
[ThTh1] Last week, Elon Musk’s company launched the first 60 satellites of the planned Starlink network, that should provide wireless internet all over the planet. Sounds good, right?
Well … not so fast. Satellites are of major concern to astronomers. It is not unusual to see the track of a satellite in an astronomical image. But with roughly 12,000 satellites planned, the potential impact is massive. The wide-field Large Synoptic Survey Telescope would have three of these things in a typical image. Even Hubble, in low Earth orbit and with a tiny field of view, would see a Starlink satellite in roughly one in a thousand images. Dozens or hundreds of these artificial stars could be visible to the naked eye on a given night.
Musk, as is his wont, has responded to these concerns by dismissing them rather cavalierly. I find his reassurances unreassuring. Among other things, he says telescopes should be in space, which is expensive, impossible in some applications and doesn’t actually solve the problem unless you put your space telescopes in very high (and expensive) orbits. Astronomers Alex Parker and Katie Mack respond to his claims. Having a little knowledge in this area, I would say they are likely far closer to the mark than Musk is.
(That’s not to mention the danger of collisions and Kessler syndrome. I’m sure Musk’s people will try very hard to keep their 12,000 satellites from crashing into each other. I’m less sure that other space agencies will be as diligent. And I’m positive random space debris and asteroids won’t be careful at all.)
I have very mixed feelings on Musk. On the one hand, he is laying out a vision of the future — frequent space flight, global internet, missions to Mars — that is bolder than anything we’re seeing from … anyone. Some of the things his companies have created, such as the Tesla and the Falcon rockets, are genuinely impressive. But he sometimes lets his vision get ahead of knowledge and has a tendency to casually dismiss concerns that experts in the field recognize. This is an example.
If Musk’s full system comes on line, this will potentially triple the number of satellite orbiting the earth. The simple fact is that no one has done the kind of careful study needed to figure out the impact of this constellation (least of all other telecom constellations being planned). And we should be doing that, both in terms of the night sky and in terms of the potential for collisions.
[ThTh2] Folks, you don’t need a PhD to do astronomy. Amateurs discover new stuff all the time.
[ThTh3] This is more in Oscar’s domain, but I couldn’t resist this amazing video.
This is the mass damper of the Taipei 101 skyscraper: it has a mass of 728 tons and a diameter of 5.4 meters. It helps stabilize the building in high winds and this is the record movement realized during typhoon Soudelor with 160 km/h winds https://t.co/e0MxA0iOG5 pic.twitter.com/riHgXD4Csr
— Massimo (@Rainmaker1973) June 2, 2019
[ThTh4] The United States has just finished an amazingly wet period of time. Is this related to global warming? Kinda hard to tell. I tend to shy away from the tendency to blame every odd weather phenomenon on global warming. But … we are doing a massive uncontrolled geo-engineering experiment and the effects of it are highly unpredictable.
[ThT5] When I started grad school, only a handful of small galaxies were known to orbit the Milky Way. But bigger telescopes have revealed more and more, changing our understanding of how the Galaxy formed.
I've updated my movie of the discovery history of Milky Way satellite galaxies.
It shows when in the past 100 years which dwarf galaxy was found. The view rotates around the MW (the white circle in the center).
blue: classical sats
red: SDSS discoveries
green: recent discoveries pic.twitter.com/2pp91d5LXH— Marcel S. Pawlowski (@8minutesold) May 31, 2019
[ThTh6] The more we find out about gut bacteria, the more important they get.
[ThTh7] Color me very skeptical of the claim that global warming will wipe us out by 2050. This sounds a lot like Ehrlich’s Population Bomb prediction and relies on estimates of global warming that are far in excess of what the IPCC says is the most likely range. I do think, however, that our global warming policy should take into account unlikely but potentially catastrophic scenarios. After all, our foreign policy is often guided by unlikely but potentially catastrophic scenarios.
[ThTh8] 2019 has now seen more measles cases in the US than in any year since 1994, which is when the Clinton Administration passed the Vaccines for Children Program that almost wiped the disease from the country. This is an ongoing national disgrace.
[ThTh9] The renewed interest in UFOs is interesting. But the ones coming out of the government files almost certainly have fairly mundane explanations.
3: that is quite a bit of movement, but a typhoon will do that.Report
ThTh3: I alternated between gaping in amazed delight and shuddering in terror at the idea of what that building must have been going through to produce that behavior in the mass damper. When they noted that the building was evacuated during the event I felt better. Modern architecture is so freaking cool. But Californian NIMBY’s say we can’t build anything over two stories in earthquake prone areas.
ThTh8: If there is a hell; the parents of these little plague kids should be rotting in it. This is an utter fiasco and a national embarrassment.
ThTh1: I am so divided on this. I mean the satellite network seems so extremely useful. I get the concerns though. Is this one of those science vs the masses things? Do the satellites being up there really screw up the science that much or is it more of an annoyance thing?Report
Regarding satellites, it’s one of those things where it’s be awful nice if perhaps, before we toss up a huge constellation of satellites, we could bring down a bunch of the useless ones that haven’t de-orbited on their own yet.Report
I like that idea. Similar to the effort to clean up Everest.Report
How hard is it though to do such a thing? I understand the velocities involved make it essentially like trying to catch flying bullets. Obviously there’s a reason all that junk in low earth orbit hasn’t decayed out of the sky already. I’m assuming, based on my miserable neophyte knowledge of space, that sending a device up to intercept one piece or one cloud of pieces of junk would be expensive but possible but that sending a device up to intercept many different clouds of junk on many different orbits is flat out impossible?Report
It’s hard. Because you can’t just use a big net. When thing collide, that just creates more debris. There has been talk of using a laser broom to ablate objects and push them down into the atmosphere.
Right now, the biggest concern is Envisat, a massive ESA satellite in a dangerous orbit that will be up there for 150 years. If I were appointed NASA head, one of my priorities would be mandating that every mission be equipped for deorbit and plans be drawn up to deorbit existing satellites.Report
If I were appointed NASA head, one of my priorities would be mandating that every mission be equipped for deorbit…
In the US, satellites are regulated by the FCC, not by NASA. The FCC has end-of-life requirements, either deorbit or graveyard orbits for geosynchronous satellites. Opinions differ on whether the Outer Space Treaty should be read to require a deorbit plan.
For private satellites, the OST places full liability for damage on the country in which the satellite owner operates. Recently there were stories in the news about a US company that couldn’t get an FCC license, but arranged to have their sub-cubesat devices launched by India. They were in serious trouble with the FCC because the US will be responsible for any damage they do. They may have been fined into oblivion — don’t know.
Cubesats generally are a problem. They mostly don’t have maneuvering thrusters, and as they are often launched as supercargo, may wind up in orbits other than those in their license.
Most countries have deorbit requirements. India and China are a problem because they don’t.Report
I’ve suggested a simple suborbital rocket that goes straight up, reaching apogee in front of the targeted satellite, and fires a pair of opposed horizontal rocket engines along the flight path. The rocket exhaust is two long plumes of rarefied atmosphere that create drag, yet not enough drag to dislodge anything on the satellite. It might take two or three such hops to bring one down, but suborbital launches of a re-usable vehicle shouldn’t be very expensive.Report
There have been a number of links on past Tech Tuesdays talking about technologies to de-orbit satellites. It’s a non trivial issue. It’s easier to have a satellite equipped with a means to de-orbit itself.
There are a lot of smart ideas out there, but resurrecting some old Reagan Era Star Wars ideas and putting a “Laser Cannon” in a high orbit, so it can zap older satellites out of orbit just sounds nifty. Targeting the laser is still a feat, but it’s one we can do well enough. I can just imagine that the award at JPL for an employee of the month is getting to be the junk gunner for a while.Report
StuffIn.Space, which lets you see all 20,000 satellites in real time. You can click on one to see its orbit and various parameters.Report
ThTh1 – Elon Musk is an idiot. He’s very smart, so his idiocy is the particular arrogant clever kind of idiocy that very smart rich people sometimes fall into, but he’s still an idiot.
ThTh7 – My understanding is that the IPCC report is unrealistically optimistic. It leaves out a couple of important feedback loops, notably the release of methane from melting permafrost.Report
I addressed that a few Th2’s ago. The methane bomb seems to be an exaggerated danger. The IPCC report has a number of scenarios, some of which are very pessimistic.Report
ThTh7 — I got e-mail from the Inslee campaign this morning. (Full disclosure: I sent Inslee money because I want the climate change issue to be as front and center as possible.) They had sent a letter to the Democratic National Committee asking that one of the debates be broadly climate focused: not just about renewable electricity, but how it should affect foreign policy, etc. The DNC response reportedly said that there would be no such debate. Further, it supposedly said that any candidates who took part in a non-DNC climate debate would be barred from all future DNC debates.
My son’s girlfriend works on climate models for NOAA/NCAR. She says that most of the known unknowns — things we know aren’t done well in the models — are things that make the outcomes worse.Report
I agree on Musk. Space X is great but damn if he is almost a cartoonishly sure he knows everything and everybody should love him rich narcissist. He is not going to cope well when he has serious setbacks and something big fails. That happens to everybody especially when they go big like he does. He is careless and clueless about things that get in his way.Report