The 60 Starlink satellites parading across the sky make an incredible sight, but some skywatchers wonder at what cost to the night.
It's a safe bet to say no one had ever seen anything like it — 60 satellites chugging across the sky in a straight line like some outer space choo-choo. We're grateful that Dutch satellite sleuth Marco Langbroek captured video. If nothing else, it will calm those who were convinced they were seeing a UFO. But as is nearly always the case, there was a more prosaic explanation: Elon Musk, SpaceX founder, sent the first volley of what will become a megaconstellation of 12,000 Starlink satellites to provide broadband internet service for under served areas of the globe.
A video of SpaceX Starlink satellites as viewed from the Netherlands on May 24, 2019.
That's right. 12,000. If all goes according to plan, SpaceX will send up fusillades of the satellites on its Falcon 9 rocket multiple times a year over until the entire constellation is complete, which will take about 9 years. Fortunately or not, depending on how you feel about sending this many machines into orbit, the incredible sight will be repeated 4–5 times again in 2019 alone. That means lots of opportunities to see the heavenly procession in case you were clouded out this time around.
Successful deployment of Starlink satellites in orbit. We see all 60 folded up tight. They will soon drift away from one another like the expanding bellows of an accordion to form the remarkable train in the sky.
During the initial orbit, the Starlink train passed over northwestern Europe at an altitude of just 440 km) and formed a neat line about 7° long that resembled a ticker tape (if anyone still remembers those) or the crawl under the talking heads on the nightly news. At the time, the satellites ranged in brightness from 1st to 3rd magnitude and were easily visible with the naked eye.
Since then, the satellites have been firing their thrusters to climb to an operational altitude of 550 kilometers with an orbital inclination of 53° — steep enough for most of the world to connect to the internet as well as see its orbiting providers.
I got my first look during a beautiful high pass on May 25th and couldn't believe my eyes. I first spotted the 60 satellites as a freaky thread of light rising straight up through Leo's tail. As it drew closer I could faintly make out dozens of tiny lights between 4th and 5th magnitude lined up like geese in flight. When low in the west, the group sight spanned some 10° (two fists) but closer to 20° when overhead. Incredibly, individual or clusters of the objects would briefly flare and fade — some as bright as magnitude 2 — which made the train sparkle like a frost-covered twig in sunlight.
Starlink satellite train with flaring on May 26th.
The view in binoculars was even more striking and looked exactly like the video, with satellites streaming by so quickly I could hardly count them. Over time, as they've reached altitude, the Starlink birds have faded considerably . . . and spread out. What used to take a few minutes for a pass now takes close to half an hour! During a 10:55 p.m. pass on May 28th, none were visible with the naked eye from my home (limiting magnitude 5 at the time), though I did see one or two flare to 4th magnitude in binoculars. Most glimmered between 6th and 8th magnitude and either appeared singly or in small bunches of two to four. I looked for nearly 20 minutes at a train more than 100° long.
If you like satellite watching, Starlink is a boon. But if you worry about humans polluting the sky with space junk, you've probably already slammed your fist on the table while reading this. Either way, the design life for the birds is around 5 years followed by a tidy and safe burn-up in the atmosphere. All are equipped with a satellite-avoidance technology to prevent crashes that might lead to the release of orbital debris.
Starlink satellites have a folding design that allows 60 at a time to be packed as tight as sardines in a Falcon 9. Once in orbit, each deploys a single solar panel to generate the electricity to power a krypton ion engine similar to the xenon ion engine used by NASA's Dawn spacecraft to travel to Vesta and Ceres. Although krypton is less efficient than xenon, it's also cheaper — a consideration if you plan to launch thousands of satellites.
Six more launches of 60 will be needed to initially activate the system. Because the satellites will communicate by lasers, the network is expected to provide higher internet speeds than what can be achieved on the ground with fiber optic cable. Light travels considerably faster across the vacuum of space than it does through glass fibers.
After 12 launches, the constellation will begin to provide significant coverage. The long-term plan will roll out in three phases with satellites launched into 53° orbits in three major orbital planes:
- ~1,600 satellites in a constellation at an altitude of 550 km
- ~2,800 objects at 1,150 km
- ~7,500 satellites at the lowest altitude of 340 km
How to See Starlink
The easiest way is to go to Heavens Above and select your location. Return to the main page and click on the Starlink leader and Starlink trailer links. These are the first and last satellites in what has now become a long procession. The leader is a several minutes ahead of the main group, so if you see just one or two at first, stick around. The others will follow along the same path.
Starlink Satellite Tracker is super-easy to use. Select your city from the drop-down list or input your latitude and longitude if your city's not on the list. You'll get a list of passes and where to look. The site also provides a live map showing Starlink's location. If you don't know your latitude and longitude, click here.
N2YO.com also shows passes and information for the Starlink Group. Just type Starlink in the Find a Satellite box. This will show the next pass. For a list of passes, click the10-day predictions link.
CalSky is another excellent site. Like the Heavens Above website, CalSky offers printable sky maps showing the satellite track. Sign in and select your city under the Setup link, then click the Satellites link. In the more detailed menu, click on Sat-Library. In the box at left, type Starlink for satellite name. Go back to the links under the heading and click Selected Satellite. In the yellow Satellite Menu box to the right, click Sighting Opportunities. Scroll down to see a list of local times, directions, and altitudes. Click Star Map to get a map of the path for a particular pass. The next time you come back you'll only have to click the Sighting Opportunities link — the site remembers the rest.
Be sure to go out a few 5–10 minutes beforehand to dark-adapt your eyes. Until the next launch, binoculars are essential for seeing these. Few if any are visible with the naked eye unless they flare. If you live near a big city it will be an even greater challenge, so try this: Check the Starlink path on a map and note when a pass takes it close to a bright star. Put that star in your binoculars then wait and watch for them to zip by. On May 28th I was lucky enough to have Polaris as my guide.
A Million Points of Unwanted Light?
Although the sight of five dozen satellites in a row will take your breath away, not a few of us are concerned about the volume of traffic over our heads. Yes, there's a lot of space up there. We get it. But in 9 years, when 12,000 of them will be crawling the skies like so many ants, will it detract from the sight of the stars at night? Some will say that most of the units will be too high to see with the naked eye, and my May 28th observation seems to be proving the point, but that lowest and most populated belt — the 7,500 at 340 kilometers altitude — will almost certainly be visible. Not just in bright twilight either. My May 25th sighting was made at 11:25 p.m.
If you're an astrophotographer, trails from Starlink may be unavoidable and require frequent and deft use of your photo program's cloning tool. For professional astronomers, imaging headaches undoubtedly lie ahead. For the visual observer, will it mean a constant reminder of machines on parade while seeking the solace of a dark sky?
In response to online concerns from amateur and professional astronomers, planetary astronomer Alex Parker tweeted his concerns that "If SpaceX launches all 12,000, they will outnumber stars visible to the naked eye," and estimates that "at midsummer midnight in Seattle about 500 of them will both be above the horizon and directly illuminated by the Sun."
Musk has already talked to his staff about making Starlink satellites less shiny. The team can also tweak the satellites' orientations to further reduce reflectivity if astronomers need to make sensitive observations. Musk has also addressed any potential conflicts with radio astronomers, tweeting that Starlink will "avoid use of certain lower Ku frequencies specifically for radio astronomy."
There are still many unknowns and a few troubling "knowns" as well. Starlink is only the first wave. Other companies plan to compete with SpaceX for your internet dollar by launching their own satellite networks. Amazon recently announced plans to launch a broadband internet constellation of 3,236 satellites called Project Kuiper in the near future. More are in the works including OneWeb and Telesat.
Despite the thrill of seeing a unique human-made wonder like Starlink and the understandable need for internet service in remote locations, some of us are worried just where this road is taking us. This statement from the International Dark-Sky Association (IDA) sums up many skywatchers' concerns in a nutshell.
Addendum, May 30: I just received this statement from the National Science Foundation's spokesperson Amanda Greenwell regarding radio astronomy and Starlink. It reads in part:
"NSF is committed to ensuring the scientific community’s access to vital portions of the radio spectrum required for research purposes. We have been working with SpaceX to finalize an agreement related to management of the affected portion of the radio spectrum and can provide more information after that agreement is finalized."