How would a space nuclear explosion affect satellites?
Recently there was an anniversary of nuclear space tests. On July 9, 1962, the USA carried out Operation Starfish – a high-altitude explosion of a nuclear charge. The power of the explosion was 1.4 Mt, the height of the explosion was about 400 km, the place of the explosion was near Johnston Island in the Pacific Ocean.
What is the relevance of this topic?
The relevance lies in the dramatic change in the military-political situation that has occurred over the last couple of decades. The world has become much more turbulent.
A couple of months ago, Russian and French media, including through the publication of interviews with high-ranking politicians, discussed scenarios for a potential exchange of nuclear strikes between France and Russia.
Ukraine has lifted many nuclear taboos. These include systematic strikes on nuclear power plants, strikes on radars of the nuclear attack warning system, etc.
The United States is seriously discussing the need to transfer nuclear weapons (NW) to Germany and Japan.
Israel, a country whose strategic situation is catastrophic, has nuclear weapons. Apparently, Iran has nuclear weapons. And Pakistan. Saudi Arabia once paid for Pakistan's nuclear program in exchange for the obligation to hand over nuclear charges upon request. And so on.
In general, there are many people who, for completely different reasons, can carry out a cosmic nuclear explosion.
It is noteworthy that the topic was started to be warmed up by such a publication as Scientific American. I repeat, this is a publication that is read in order to know what needs to be discussed today in a decent pseudo-scientific society.
So what happens if, or rather when, a nuclear explosion occurs in space?
It is clear that those satellites that are near the explosion will be destroyed. But what will happen to the rest? Let's figure it out.
There are many myths around the topic – in both directions – both about supercriticality and about explosion safety. Therefore, in attempts to understand something, let's rely on undoubted facts.
It is obvious that the plasma dynamics from a high-altitude nuclear explosion is a complex nonlinear nonlocal problem. It cannot be solved theoretically. And no non-nuclear experiments can fully model what is happening.
First fact. Nuclear weapons have not been tested in space for six decades.
The second fact. It was not possible to obtain full scientific data during the tests. And there were few satellites at that time. And the equipment used did not fully allow measuring the effects being studied. And so on. And, of course, the full scientific data obtained then have not been published.
Here, for example, is an experimental one article from 2006. Experimental – because only then were scientific data from different satellites properly calculated and synchronized, which made it possible to describe some of the consequences of the explosion much more accurately than before.
A collection of papers from American symposia on the “Starfish”, translated into Russian and published in 1964 – https://elib.biblioatom.ru/text/operatsiya-morskaya-zvezda_1964/p0/
The speakers repeatedly emphasize that the sensor equipment was imperfect and many parameters were measured indirectly and very approximately. For example, by the rate of degradation of solar batteries.
The third fact. Many satellites were damaged by the effects of the nuclear explosion.
For example – US Navy navigation satellite Transit 4B. Moreover, the explosion occurred on July 9, and the satellite stopped working on August 2. It is important that the satellite had a nuclear power source SNAP 3. That is, the satellite equipment was designed to withstand radiation.
Thus, artificial radiation belts were formed. They affected the satellites for months. And a number of them were put out of action.
The question is where exactly these radiation belts were located. I couldn't find any clear answers to this question. Let's assume that I didn't search well, but I think there are other reasons – see the second fact. So let's approach it from a different angle.
The South Atlantic Magnetic Anomaly is the region where the inner radiation belt comes closest to the Earth's surface, dropping to an altitude of 200 kilometers. This results in an increased flux of charged particles in the region and exposes satellites (including the ISS) to higher than normal levels of ionizing radiation.
How did the Sea Star affect the charged particle flows in the area of this anomaly?
I did not find an answer to this question.
However, there are statistics on failures of satellite electronics in this area under normal conditions.
Picture from books “Radiation effects on spacecraft materials”, Novikov L.S., 2010.
Above – places where single failures in the satellite's dynamic memory occurred. (Orbit – 700 km). Below – proton flow of the radiation belt.
So, we have found out that if a cosmic nuclear explosion occurs, then due to the existence of the South Atlantic Magnetic Anomaly, many even low-orbit satellites will spend part of their time in an artificial radiation belt.
And what negative phenomena are there when staying there? What damaging factors?
First – this is the very fact of the satellites being in the radiation belt.
I will again refer to the Scientific Research Institute of Nuclear Physics of Moscow State University. Book “Interaction of spacecraft with the surrounding plasma”, author – Lev Simonovich Novikov.
The satellite passes the South Atlantic Anomaly in a few minutes. This is more than enough time for it to become electrified to equilibrium with the surrounding plasma.
At the same time, most low-orbit satellites are not adapted to work in such conditions. They must operate in plasma with a temperature of about 1000 K and a Debye length of about a centimeter. And suddenly they find themselves in plasma with a temperature of tens of keV. The satellite bodies are not hermetically sealed; non-conductive materials are widely used. And that means – hello differential electrification – when one part of the satellite has one potential, and the other – another; and that means – there will be breakdowns.
In addition, there will be a noticeable flow of charged particles with energy in MeV-s. This means that breakdowns can occur not only between individual elements of the satellite, but also inside non-conducting elements. Their results are called Lichtenberg figures – see photo below.
The second damaging factor – high-energy charged particles.
This factor has an impact Firstly on electronics.
IN Wikipedia articlededicated to the South Atlantic Magnetic Anomaly, lists a number of high-profile cases of failure of spacecraft electronics caused by this factor.
The most interesting thing is what they write about the use of ordinary personal computers on the Shuttles. It is interesting because such civilian electronics are too often installed on low-orbit satellites. In addition, the trend of placing computing power on satellites for processing information directly in orbit is currently actively developing.
The text dedicated to the Shuttle's onboard computer is no longer on the NASA website. But copy in internet archive preserved. The excerpt below explains why the Shuttle's old, slow GPCs (pictured) can't be replaced with new laptops.
_________
A ThinkPad 760XD laptop experiences two to three memory changes due to radiation during a Shuttle mission to the ISS. That number increases to 30 for a mission to NASA's Hubble Space Telescope. That's because Hubble orbits about 150 miles above the station, where the Earth's magnetic field shields it from radiation less well.
The developers also discovered that the laptops would fail when the shuttle passed through the South Atlantic Anomaly.
_________
And all this is inside the Shuttle. The satellite's electronics are much less protected.
Optics
Naturally, high-energy particles will affect not only computers, but also, for example, camera matrices. This will not only result in “sparks” on the pictures, but also a gradual degradation of the matrices.
In addition to matrices, ionizing radiation will also destroy optics – effects of coloring and clouding of glass, as well as reduction of transparency. The values of critical doses for some materials are given in book L.S. Novikova “Radiation effects on materials of spacecraft”.
Solar panels
Yes, modern solar panels have higher radiation resistance than old silicon ones. The question is how much higher. From the data cited by Novikov in the same book, it follows that the maximum permissible dose of modern solar panels is about an order of magnitude higher (slightly less than an order of magnitude, 5-8 times). That is, if from one explosion 60 years ago satellites stopped working after 20 days, then now the same satellites will stop working after 200 (if the radiation belt remains that long). But now satellites are different. Again, the factor of commercial benefit – why does a satellite need an extra resource? What share of energy from solar panels can a satellite lose and remain operational? And then, who said that there will be one explosion?
Again, the performance of remote sensing satellites is largely limited by their capabilities and the speed of information transfer to Earth. Less energy means less transmission time.
And if the satellite itself will calculate the images, then synergetic effects will arise – degradation of the optical system, calculation errors, reduction of energy for calculation, reduction of energy for information transmission. How much will the efficiency of such a system decrease?
So what happens after a nuclear explosion in space?
Based on what has been written above, we can assume that the scenario will be as follows.
Satellites located near a nuclear explosion will be destroyed immediately.
In a few days, some satellites crossing artificial radiation belts will fail. The reason for the failure is their inability to withstand the effects of high-temperature plasma.
Satellites that are properly designed from the standpoint of electrophysics will continue to operate. But due to the presence of a high-energy particle flux, their solar batteries, electronics, and optical systems will degrade. If the satellite's orbit is unsuccessful, these factors will disable it in a few dozen days. If it is more successful, the satellite's active life will be shortened.
What protective strategies can be taken?
The first of the obvious ones is to make “tanks” – spacecraft that are well protected from negative factors.
The second obvious strategy is to lower the satellite's flight altitude as much as possible. Yes, it won't live long. But none of the “cheap” satellites will live long. And in ultra-low orbits, the negative factors have a weaker effect. And the Earth is visible better.
Is this the reason why the West has recently been actively developing the direction of creating #VLEO satellites?
The third strategy is to use higher orbits. There, satellites have to operate in an environment that already has the negative factors that arise after a nuclear explosion in space. Therefore, for many orbits, the difference in external conditions after a nuclear explosion will not be qualitative, but quantitative.
In any case, the cost of using space is rising sharply.
And the cost will increase only because there is only the possibility that someone will use a space nuclear explosion for some purpose – the product of the probability of an event and its damage to military and other critically important systems is too large.
