If you’re like me, you’re aware that GPS satellites exist as
do various surveillance satellites but you probably have no idea where they’re
located (orbital height above sea level) or what this means in terms of war in
space and satellite survivability.
Most people assume that all orbiting objects exist at more
or less the same altitude but this is not the case. There are various bands of orbits at various
heights out to around the geosynchronous orbit at 36,000 km (22,500 mi). Further than that is the so-called graveyard
orbit where satellites are parked at the end of their operating lives if they
are not de-orbited.
The two main orbital bands of interest for us are:
As a point of comparison, the Earth is around 4000 miles in
radius (center of the Earth to the surface of the oceans)
Space has become a crowded place.
A National Interest website article suggests that China has the
capability to achieve anti-satellite kills at orbits out to Geosynchronous
altitudes (35,786 km / 22,236 mi).[4]
One of the implications of the crowding of orbits is that when
war with China comes and anti-satellite weapons are used by both sides, the
number of objects (debris) in orbit will increase by orders of magnitude likely
resulting in a cascade of collisions (at orbital speeds, any collision is
probably totally destructive) with surviving satellites resulting in ever more
debris and ever more collisions. In
other words, at some point, a chain reaction will occur which will destroy all
satellites in a given orbit.
Legitimate uses are also contributing to the crowding.
Space is a lot more complex, in terms of military use and
combat, than most of us realize and the implications of combat in space are
poorly understood by almost all of us.
- Low Earth Orbit (LEO) (<2000 km / 1,200 mi)
- NavStar GPS Orbit (20,180 km / 12,540 mi)
US Space Command, which currently is responsible for monitoring the heavens, is tracking some 41,000 pieces of space junk bigger than 10 centimeters … [1]
… NASA, tracks over 25,000 objects larger than 10 cm in LEO, the estimated number between 1 and 10 cm in diameter is 500,000. The amount of particles bigger than 1 mm exceeds 100 million.[3]It’s becoming even more crowded by the debris fields of anti-satellite (ASAT) tests. Russian and Chinese ASAT test debris accounted for 20% of orbital collision warnings in 2022.[1]
… the 700 to 900 kilometer band of LEO, a region that is increasingly crowded due to advent of mega-constellations such as SpaceX’s Starlink communications satellites. That orbital altitude also is being used by the Space Development Agency for its planned Transport Layer of 300 to 500 high-speed, high-volume communications birds.[1]LEO confers interesting capabilities and limitations.
Unlike geosynchronous satellite, satellites in LEO have a small field of view and so can observe and communicate with only a fraction of the Earth at a time. This means that a network (or "constellation") of satellites is required to provide continuous coverage. Satellites in lower regions of LEO also suffer from fast orbital decay and require either periodic re-boosting to maintain a stable orbit or launching replacement satellites when old ones re-enter.[3]As a reference and point of interest, the 20-Feb-2008 shootdown of satellite USA-193 by a SM-3 Standard missile launched by USS Lake Erie occurred at an altitude of around 250 km (155 miles).
https://breakingdefense.com/2023/06/debris-from-asat-tests-creating-bad-neighborhood-in-low-earth-orbit-analyst/
https://en.wikipedia.org/wiki/Global_Positioning_System
https://en.wikipedia.org/wiki/Low_Earth_orbit
https://nationalinterest.org/blog/buzz/how-china-could-win-war-against-america-kill-satellites-85176
I think another important thing to understand is the lack of total area surveillance and just what current satellites are or are not capable of. A good example being the assumption that a CVBG cant "hide" in the Pacific- when in fact, in order for the Chinese to constantly surveil just the SCS, itd take thousands of satellites to have constant real time coverage with any kind of targeting-quality, never mind the Phillipine Sea or larger areas of the Pacific. Nobody, US included, has that ability. So while there are satellites that might read a newspaper headline from space- the notion of being able to watch other nations every move- especially at sea- just isnt realistic. Not yet anyway. This isnt somthing I realized until doing some reading and research for a post here a year or so ago...
ReplyDelete"The grave's a fine and private place": space isn't though. Too transparent.
ReplyDeleteSubmarines - they inhabit a private place, largely, don't they?
Starlink lower than stated in the quote, around 550 km.
ReplyDeletehttps://www.starlink.com/technology
Their future expansions will be in even lower orbits.
The lower orbits allow their satellites to be cheaper and have lower latency. There is little need for redundancy or over engineering since the satellite will fall out of the sky in a few months if it fails. A failure in the 1000 km orbit can have catastrophic implications. They've also spent a lot of effort making sure the satellites will burn up and parts won't crash on earth.
Of course drag is a concern, as you mentioned. SpaceX developed better thrusts that can use cheaper reaction mass. Many satellites have Hall-effect thrusters that use electricity from solar panels to accelerate a noble gas like Xenon and propel the satellite via Newton's third law. Xenon is really expensive so SpaceX figured out how to use Krypton. That was still too pricey so now they use much more available Argon in the V2 satellites.
Better thrusters -> more capability to handle lower orbits. And debris get swept quickly in these orbits so they'll stay cleaner. The international space station has a very low orbit for this reason, it reduces crew risk.
Just like the mainstream doesn't understand space they also don't realize how dramatically the technology has changed in the last five years. The old rules are completely obsolete. The implications are staggering and it is the US that dominates the technology because of SpaceX. Take a peak at this chart if you don't believe me:
https://ourworldindata.org/grapher/yearly-number-of-objects-launched-into-outer-space
For the military the obvious route is to move all capabilities to low orbit on constellations of cheap satellites that will be more robust to enemy attack and interference.
I think they still need to be robust enough to survive the sort of attack (like an EMP attack or maybe radiation from nuclear burst) that might take out a whole bunch of them at once.
DeleteI think that is a harder question than you think. If we are talking a $1 billion satellite In geosynchronous orbit that takes years to build and launch, then yes. And it is more exposed to space weather there, anyway.
DeleteA $200,000 satellite in LEO might be different because you can just launch more and the enemy will struggle to blind more than a fraction of your capability at once because of the number of satellites and their dispersal across so many orbits.
Remember, SpaceX’s goal is to launch hourly. Others will follow.
Remember, an EMP strike affects everything within line of site of the source. That could be a LOT of satellites.
DeleteI think you are giving EMP some powers it does not have. Its effects even in line-of-sight scenarios are highly variable. That is because radiation diminishes rapidly, especially when there is some atmosphere providing mass for particles to collide with. There is a band of LEO satellites above the atmosphere and below the Van Allen belts that is most vulnerable.
DeleteYou can read more about this here:
https://apps.dtic.mil/sti/tr/pdf/ADA531197.pdf
Please note the difference in damage probability between the lower orbit ISS and the other satellites. And also see that many affects take weeks or months to lead to failure, which is fine if you have a capability to rapidly launch satellites.
EMP bursts are not free and you can put cheap satellites in orbits that will be expensive to destroy.
No worries! ...Only 66 percent of 18-24 year-olds are firmly convinced of our planet's spherical shape.
ReplyDeletehttps://www.sciencealert.com/one-third-millennials-believe-flat-earth-conspiracy-statistics-yougov-debunk
The youngest Millennials are 27 in 2023 so these would be Gen Z.
DeleteThis is one of the reasons the Space Force was created. Instead of a mishmash of jobs USAF (which is dominated by F-35 worshipers not Space) or part of the Joint cluster...er, Joint command SpaceCom which works as perfect as every other joint command we have a specific branch focusing on the challenges . For the new guy they aren't doing too bad. Since getting spun up, they have started programs looking at hardening satellites against space debris, getting small rocket companies to work on mobile small satellite launchers (less vulnerable to attack on the ground), and reducing launch costs for military launches.
ReplyDeleteLong term, they are looking avoiding the Kessler Syndrome (What NASA calls the chain reaction collisions you described) as well as enemy interception by using cislunar space--orbits between the Earth and Moon beyond GEO. While not there yet, if SpaceX's Starship becomes reality, its performance makes not only cislunar possible but its payload capacity of 100 tons means you can deploy as many as 5-10 replacement GPS satellites at once or literally a couple hundred small LEO sats.
I do wonder if what Musk really wants to do is launch Starship from a dormant volcano to swallow other space ships whole while stroking a Persian cat, but so long as he still launches US satellites cheap I'm ok with that.
There is a good argument that we are already in the early stages of Kessler. A few dozen ASAT missions will seriously accelerate it. Eventually, it may get to the point where LEO is completely unusable, and even launching through it to higher orbits will be extremely high risk.
DeleteWhy are we worried about satellites and Kessler syndrome? Just shoot them down. We fought WW2 without satellites. We survived until the 80s without satellites.
ReplyDeleteBecause sadly, we are quite dependent on them....
DeleteComNavOps doesn't seem to think so. That's an opinion he's expressed in the past.
Delete"We survived the 80's without them"
Deletetwo things wrong with that:
First, the military has been dependent on satellite intelligence since the 1970's for intel on Russia and China. We have been using satellite meteorology for just as long. We have grown dependent because it was effective. It was not cheaper or easy till only in the last decade or so. Before that it was expensive, difficult, but the need outweighed it. The first nav sat was in 1978. The GPS network was being developed and launched in the 80's not because it was cool, but because inaccurate navigation through older means has gotten people killed in wartime. We shouldn't have gotten dependent, but it was and is a legit need. For that matter people are still crashing ships WITH GPS.
Secondly, you are not just talking about military dependence--you are talking about the entire modern economy of the USA. Space based communications, imagery, and remote sensing are primary drivers now.
The weather forecast--which effects everything from crops to when to jump into a shelter to storms that can wreck a naval fleet--satellites. In the war with Russia, a relatively new satcom service-Starlink-has been vital due to interference from other forms of communication by Russian jamming, severing landlines, and other effective EW.
Trading stocks, govermment and civilian email, even hell your refrigerator nowadays is part of the internet which is 40% space-based and will be 80% space based in a decade or two due to bandwidth needs.
We find fresh underground resources from satellite sensing.
And as for the military, for all the use of drones for ISR, observing China or Russia itself is satellite based. When that old-fashioned spy tells the CIA about what which general is about to be sacked by Putin, its probably on an encrypted satellite phone.
The list is practically endless.
Yes, the Navy needs to be less satellite dependent, but the final frontier isn't something we can simply dismiss.
My dude, are you actually daring to argue that ComNavOps is wrong? Perish the thought!
Delete"ComNavOps doesn't seem to think so. "
DeleteYou may be misunderstanding my view, a bit. We are 100% dependent on satellites BUT WE SHOULDN'T BE. It's become a dependency and, like all dependencies, it weakens us.
We need to be able to operate without satellites and then, if they're occasionally available, all the better. Satellites should supplement our capabilities not replace our basic skills.
"One of the implications of the crowding of orbits is that when war with China comes and anti-satellite weapons are used by both sides,"
ReplyDeleteThat's a big and expensive assumption that we'll jump straight to destruction when degradation, disruption, and denial are cheaper, and destroying a com sat used by your enemy may also destroy the same com sat your banks/allies/industry are using to communicate. This reality actually forced some space thinkers into considering a Mahanian approach to space warfare, with satellites as proxies for ports.