With the next solar maximum on the horizon – where solar activity peaks – new space players are operating in an environment unlike what they have seen before, according to authors of a recently published editorial in the journal Space Weather.
Increased solar activity leads to intensified space weather, which can be disruptive to satellites and rocket launch operations. New space companies have operated almost exclusively in periods of weak or very weak solar activity, but this is now returning to a more “normal” level.
“The last time the sunspot number was higher than it is now, SpaceX was a 6-month-old company, Rocket Lab was still 4 years from being founded, and the first standardized CubeSats were still 1 year from being launched,” the authors write.
The SMC asked local experts to explain the science behind space weather and comment on implications of a solar maximum for our aerospace industry.
Dr George Buchanan, Guidance, Navigation, and Control Team Lead – Neutron, Rocket Lab, comments:
“With the rise of smaller and higher-performance satellites in low earth orbit comes increased sensitivity to solar radiation.
“Traditionally satellites are expected to last for decades, use radiation hardened electronics to protect against space weather, and are in higher orbits which already see more harsh environments.
“In the last decade the proliferation of cheap, high-performing, consumer-grade electronics has led to a rapid increase in the number and capability of satellites, which are predominantly placed into low earth orbit where there is still noticeable atmospheric drag even at a solar low (this is partially done to reduce their orbital lifetime and minimise space junk).
“With increased solar activity comes increased tropospheric and exospheric density, and Rocket Lab has already experienced instances of customers requesting higher orbits to increase orbital lifetime due to this increased density.
“Solar phenomena are not unknown to space companies, of course, and smaller satellites with reduced redundancy and smaller transistor sizes see electrical upsets even at a solar low.
“Various common techniques are used to mitigate the impact of these upsets. However, high sun activity is likely to have outsized impact on these smaller satellites, whether that is interrupted operations or permanent damage.
“The current solar cycle has risen faster than expected, and so space weather has rapidly become an area of interest for new space companies.”
Conflict of interest statement: None
Craig Rodger, Beverly Professor of Physics, University of Otago, comments:
“Sunspots are one of the most visible aspects of the roughly 11-year solar cycle – and the solar cycle is a very important indication of how disturbed the Sun is.
“Sunspots are cooler regions of the solar surface, and hence appear darker than their surroundings. They have magnetic fields which are more than one thousand times more intense than the Sun’s global average field, and are locations where the magnetic field which is normally inside the Sun pokes outward.
“Typically we see a clean pattern of highs and lows in sunspot levels, recurring every 11-years. When sunspot numbers are high, we call it “solar maximum”, and the Sun is more active in all senses – so more background X-ray output, extreme ultraviolet output, and more explosions in the form of solar flares and solar tsunami (coronal mass ejections). When sunspot numbers are low, a time called “solar minimum”, the Sun is much less active and variable – essentially, it is a time of “solar boring”.
“Increased solar activity will lead to more aurora visible over New Zealand, which is a good thing! But it will lead to more space weather events, changes in the near-space environment which can be disruptive to satellites and other technologies (including communications systems and even power grids).
“Right now, we are in the increasing phase, coming out of a deep solar minimum heading towards solar maximum. There is a bit of an argument right now as to when solar maximum is expected, but it is probably 1-2 years away.
“The space age started with the launch of Sputnik 1 in October 1957. This was around the peak of solar cycle 19, and the monthly sunspot average number was 360. During most of the space age the solar cycles peaked at monthly values well over well over 200 sunspots, with some months getting close to 300. The last solar cycle was pretty weak, with the peak in early 2014 being only 146. The current solar cycle has increased faster than predicted, with higher numbers. A couple of months ago in June/July, the peak was about 160 – which is higher than the peak last solar cycle, and the largest sunspot number since September 2002, when the monthly sunspot number was 188.
“It is true that the new space launch companies are operating in an environment which is different from what they have seen before, which is why the editors of AGU’s space weather are pointing this out. Having said that, the current conditions are still quite a lot quieter than was experienced for most of the space age. The modern era, say from 2008, has been rather boring in comparison with 1957-2007.
“We are just starting to see some events this year which are more intense and interesting, but not on the scale of earlier times. We’ll have to see if this solar cycle is more like late 80’s/early 90’s, which was about twice the magnitude, the late 1950’s, which was about two and half times the magnitude, or a bit of a fizzer, like 2012-2014.
“On the plus side, we are getting more and better aurora over New Zealand.”
Conflict of interest statement: “I receive NZ government funding to undertake my research (working alongside the NZ energy industry), and also to operate equipment in Antarctica (working with AntarcticaNZ). I am paid by the University of Otago. I have some national and international science leadership roles.”
Loic Catuhe, Radio Frequency System Engineer, Rocket Lab, comments:
“Once a rocket lifts-off and ascends through the lower density layers of Earth’s atmosphere, it is less protected against the various fluxes and outbursts of the Sun as it reaches space.
“Charged particles emitted from the Sun can interact with a rocket’s electronics and radio frequency signals. These particles create charged plasma in the high-altitude atmospheric layer called the ionosphere which can affect the sub-systems rockets require for positioning; in particular, Global Positioning System (GPS) signals.
“As this phenomenon is dynamic and related to solar fluxes, large events like the geomagnetic storms seen more frequently at certain phases of the solar cycle can lead to the functional loss of these positioning systems.
“Thermal effects linked to unusual atmospheric heating during such events may also change the drag profile of rocket launches, which could impact how satellites are delivered to orbit.
“Understanding of these solar behaviours and impacts as well as their forecast has a direct link to the reliability and performance of global rocket launches.”
Conflict of interest statement: None