Meteor showers present spectacular skywatching alternatives for observers on the bottom as meteoroids — grains of cosmic mud left by comets — expend, producing sensible “taking pictures stars” as they enter Earth’s environment.
The subsequent huge meteor bathe to grace our skies is the Perseid meteor bathe which is predicted to peak round Aug. 11-12.
However when a meteor bathe douses Earth, does it pose any risk to satellites, spacecraft or astronauts on the Worldwide Area Station (ISS)?
Normally, completely not, mentioned Invoice Cooke, head of NASA’s Meteoroid Setting Workplace at Marshall Area Flight Heart in Alabama.
“In case you are contained in the ISS, meteoroids pose zero threat,” Cooke instructed Area.com.
How the ISS is protected against meteoroids
Astronauts are shielded from meteoroids as a result of the ISS is provided with a “Whipple bumper.” Named after its inventor, Fred Whipple — who developed the “soiled snowball” mannequin that describes the make-up of comets — the defend options sheets of steel with Kevlar between them. The defend would not deflect meteoroids, nevertheless it breaks them up, dispersing their power into the defend.
“The chances of a meteoroid penetrating the area station are vanishingly small — you may consider the area station because the tank of low Earth orbit,” Cooke mentioned. “In the event you have been an astronaut on EVA [extravehicular activity, i.e., a spacewalk] and also you went outdoors the area station, you’d see all these little pips and dents within the hull.”
Nevertheless, solely about half of these dents are attributable to meteoroid strikes. On the ISS’ altitude of between 230 and 285 miles (370 to 460 kilometers), half of the impacts are attributable to area junk as a substitute, and infrequently, the ISS must maneuver to keep away from area junk.
In truth, meteor showers pose hardly any downside to the ISS, in response to Cooke. Statistically, it’s the sporadic background of meteoroids — the bits of cosmic mud which might be all the time there, unassociated with any bathe — that contribute 90% to 95% of the hazard, significantly to spacewalking astronauts who do not have that bumper shielding. That is why, earlier than any spacewalk, Cooke’s workplace points a meteoroid forecast to make sure there is no such thing as a heightened threat of an accident.
What are meteor storms?
The strongest annual meteor bathe, the Geminids, which peak in December, poses solely about 60% the danger of the sporadic background, in response to Cooke. “Solely throughout a meteor storm or outburst are the meteor charges considerably elevated,” he mentioned.
A meteor storm, or meteor outburst, is an amped-up meteor bathe with doubtlessly greater than a thousand meteors seen within the sky per hour. Meteor showers happen when Earth passes by the path of mud left by a comet. Earth encounters these numerous trails on the identical factors in its orbit every year, which is why every meteor bathe happens on the identical time every year. Nevertheless, we get a meteor storm when Earth passes by a denser patch of mud than ordinary.
Only some meteor showers expertise storms. The Leonids, which peak in November, have a number of consecutive years of storms spaced 33 years aside. The final Leonid storms have been between 1998 and 2001, so the following are scheduled to happen within the early 2030s, when Earth will encounter that significantly dense clump of mud from comet Tempel-Tuttle.
Much less predictable are the storms of the Draconid meteor bathe, which peaks in October. Ordinarily, the Draconids present a reasonably drab spectacle, as they’re composed of predominantly faint and slow-moving meteors, however in 1933, a Draconids storm resulted in 6,000 meteors per hour. The final storm, in 2018, produced a relatively meager 150 meteors per hour.
Then, there’s the Perseid meteor bathe, which peaks in August and might randomly surge for a number of hours; the newest such outburst was in 2021.
Storms and outbursts are “batten-down-the-hatches kinds of deal,” Cooke mentioned. Whereas the area station’s bumper defend nonetheless protects astronauts inside, spacewalks are postponed and different satellites and spacecraft should take precautions. For instance, the Hubble Area Telescope reorients itself so it’s not wanting on the meteor bathe radiant (the route the meteors are coming from). Cooke likened it to “the nuclear assault place, together with your rear dealing with the radiant.’
The chance of meteor showers to satellites
The chance to any given satellite tv for pc is minimal as a result of individually, they’ve a small cross-section, a number of tens of sq. meters. As compared, the ISS’ photo voltaic arrays alone span 114,000 sq. ft (10,600 sq. m), and even that’s dwarfed by the large expanse of the night time sky.
“Once I lay on my again, wanting up on the night time sky, I am taking in roughly 30,000 sq. kilometers [12,000 square miles] of environment that the meteors are burning up in,” Cooke mentioned. “Now examine that to tens of sq. meters. So the percentages of a meteor hitting a satellite tv for pc are small.”
The chance shouldn’t be zero, nevertheless. On uncommon events, satellites have been hit, though the one satellite tv for pc ever to be completely taken out by a meteor bathe was an Olympus communications satellite tv for pc throughout a Perseid outburst in 1993. A couple of others have recorded anomalies ensuing from a small impression, and one or two have even been knocked on their aspect by a meteoroid strike.
“For instance, an NOAA satellite tv for pc was hit a number of years in the past, and that satellite tv for pc type of acquired bumped just a little bit; it tilted ahead so its digicam was now not wanting on the Earth, and we needed to get it again pointing the best approach,” Cooke mentioned.
How one can assist
The Meteoroid Setting Workplace’s monitoring of meteor showers relies on observations from the bottom, the place meteor charges are counted, alerting scientists to any impromptu outbursts that might have an effect on satellites or spacewalkers. Meteor observations can come from skilled radar, such because the Canadian Meteor Orbit Radar, which is managed by researchers on the College of Western Ontario, and the Southern Argentina Agile Meteor Radar.
Newbie astronomers also can present observations. For instance, the World Meteor Community consists of over a thousand cameras worldwide, whereas organizations such because the American Meteor Society, the UK Fireball Alliance, the British Astronomical Association and the International Meteor Organization all settle for studies from newbie astronomers.
So, the following time you depend taking pictures stars throughout a meteor bathe, notice what number of you see, what time and date they happen, their coloration, how vibrant they’re, and the route wherein they journey. (A good telescope might help you get a extra detailed view.) Then, submit your report back to one of many above organizations. Your observations may contribute to defending a satellite tv for pc or a spacewalking astronaut.
General, low Earth orbit is fairly protected from meteors.
“This notion of meteor showers being this swarm of particles that blows satellites to kingdom come — that is all Hollywood,” Cooke mentioned. “That by no means occurs.”
