Solar Racing Basics: Map

Finishing up the analysis of my Solar Racing Basics Poster (see this tag), the central portion of the poster shows the route of the World Solar Challenge (although there will be no WSC until 2023). The race traditionally starts in Darwin and finishes in Adelaide, with nine compulsory 30-minute control stops in Katherine, Daly Waters, Tennant Creek, Barrow Creek, Alice Springs, Kulgera, Coober Pedy, Glendambo, and Port Augusta (solid white dots on the map). There is also rest time between 17:00 and 8:00 each night.

To read more about the route, see this detailed post.

Click to zoom / Image credits: Agoria Solar Team (wind tunnel), American Solar Challenge (chassis), Solar Team Eindhoven (Cruiser car), (battery & motor), Vattenfall Solar Team (race strategy), public domain (lower right 3), Anthony Dekker (remaining 7).

Solar Racing Basics: Media

Click to zoom / Public domain image

Continuing the analysis of my Solar Racing Basics Poster (see this tag), documenting the construction and racing of the car is important for the sponsors, for the fans, and for the team itself. Teams that want good sponsorship need a good media subteam. Good media helps a team convince potential sponsors that they are legitimate, and can provide a quid pro quo to existing sponsors. Solar Team Twente from the Netherlands is an example of a team with good media. In particular, they have a website and six kinds of social media:  .

Often the media subteam includes a specialist photographer, such as Jorrit Lousberg (Vattenfall/Delft), Hans-Peter van Velthoven (Vattenfall/Delft), Bart van Overbeeke (Eindhoven), Jerome Wassenaar (Twente), or Joseph Xu (Michigan).

In addition, media subteams will often “place” stories in local newspapers. It’s big news in Springfield, population 24,000 (to pick an imaginary example), that a young man or woman from the town is off to race a solar car on the other side of the world. Equally, it’s big news for Dutch-language media in Australia, such as SBS, that Dutch solar car teams have arrived in the country (and ditto for Italian, Turkish, and several other languages).

Media can also act as damage limitation in a crisis. In 2017, the Persian Gazelle 4 car from the University of Tehran was heavily damaged in transit, and was unable to race, leaving the team with very little to show for all their hard work. In 2019, NunaX from Vattenfall/Delft Solar Team was totally destroyed by fire during the race, but the team could still point to the copious media of the car and say, with justified pride, “we built that”:  .

It is, of course, important that teams not make classic media errors, such as constantly changing social media “handles,” retiring social media channels without proper announcement, not keeping the website up to date, or posting embarrassing photographs that you wouldn’t want a potential sponsor to see.

To read more:

Current NASA DSN tasking

My visualisation of current NASA Deep Space Network tasking as per (click image to zoom). Several Mars orbiters are lending a hand to transfer Perseverance imagery from the Martian surface, while other space science is going on as normal.

The chart is for 2 PM Australian time, with the Sun overhead in Tidbinbilla, Australia, and Mars overhead in the 7 PM evening sky in Goldstone, California. The respective skies looked like this (click to zoom):

Later in the afternoon, as Mars rose in the sky, Tidbinbilla began to share the load of Martian traffic. As Jupiter and the Sun rose over Madrid, MDSCC prepared to take over traffic from Juno.

Mars Perseverance

NASA Mars Perseverance mission (click to zoom): top left: Mars Reconnaissance Orbiter photographs Perseverance descending by parachute, top right: onboard camera photographs Perseverance on final descent by jet-pack, bottom left: onboard camera looks out at Mars, bottom right: artist’s impression of Perseverance on Mars.

NASA’s Mars Perseverance mission, launched last July, landed on Mars yesterday. As well as the Perseverance rover, there is a small robot helicopter called Ingenuity. The landing site was the Jezero crater. We look forward to lots of interesting data, so keep an eye on

Planet Narnia: a book review

Planet Narnia: The Seven Heavens in the Imagination of C. S. Lewis (2008) by Michael Ward

More than a decade ago, on a blog that no longer exists, I reviewed Planet Narnia: The Seven Heavens in the Imagination of C. S. Lewis by Michael Ward (written a few years before Ward converted to Catholicism). Ward’s thesis was that C. S. Lewis wrote The Chronicles of Narnia based on a secret plan linking the seven novels to the seven classical planets (Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn). This plan was allegedly so secret that Lewis shared it with none of his friends.

People are still reading Planet Narnia, so it’s worthwhile re-stating my opinions, especially since I’ve done some recent analyses that are relevant.

While Ward’s book has been widely praised, not everybody has agreed with his thesis. In an interview, Lewis’s stepson Douglas Gresham stated, “A very nice man and a friend of mine, Michael Ward, has recently written and published a book all about how the Narnian Chronicles are all based on the seven planets of the medieval astronomical system. I like Michael enormously, but I think his book is nonsense.

Devin Brown is one scholar who is critical. Brenton Dickieson is another. In fact, in a letter to a child, Lewis himself is quite clear that there was no plan: “The series was not planned beforehand as she thinks. When I wrote The Lion I did not know I was going to write any more. Then I wrote P. Caspian as a sequel and still didn’t think there would be any more, and when I had done The Voyage I felt quite sure it would be the last, but I found I was wrong.

There is something terribly seductive about correspondence theories like Ward’s. Plato, for example, argued that the atoms of the “four elements” (Earth, Air, Fire, and Water) corresponded to four of the Platonic Solids. Earth atoms were cubes, because cubes can be stacked to form shapes. Water atoms were icosahedra, because water flows and icosahedra are the roundest of the Platonic Solids. Fire atoms were tetrahedra, because fire burns, and that’s obviously a result of the sharp points on fire atoms. And by now we’re basically just assuming the hypothesis, so we simply state that air atoms are octahedra. Plato was a great philosopher, but that isn’t how reasoning is supposed to work.

In a similar vein to Justin Barrett’s “Some Planets in Narnia: A Quantitative Investigation of the Planet Narnia Thesis” (Seven, vol. 27, Jan 2010), I have explored the frequencies of 20 words or word groups associated with the seven planets (I allow for variations in word endings). The 20 bar charts show the frequencies, adjusted for the total word count of each book (but the small white numbers show actual counts). The bars list the seven Narnia books in order of internal chronology (i.e. The Magician’s Nephew first). The stars mark the book that Michael Ward thinks is associated with the relevant planet; the star is black if the relevant bar is indeed the highest.

One might add the exclamation “By Jove!,” which occurs only twice in the supposedly “Jovial” The Lion, the Witch and the Wardrobe, but 5 times in Prince Caspian and 4 times in The Silver Chair. Looking at the chart, we start well with two “hits” linking the Sun with The Voyage of the Dawn Treader, but then there are only four more hits (and most of those can be explained purely on the basis of plot). All up, 6 hits out of 20, when we would have expected 20/7, or just under 3. This is not statistically significant.

It is also worth noting that we know how Lewis wrote when he was making connections to the planets. For example, Lewis’s Perelandra is based on Venus, and Lewis throws in 7 references to the metal associated with her: “coppery” (3×), “copper-coloured” (3×), and “coppery-green” (1×). There are no such references in Out of the Silent Planet, and just one in That Hideous Strength (and that is in a reference to Venus: “I have long known that this house is deeply under her influence. There is even copper in the soil. Also – the earth-Venus will be specially active here at present.”). However, there is only one mention of copper in The Magician’s Nephew, which Ward claims is also linked to Venus (“The feathers shone chestnut colour and copper colour.”). That is to say, an important Lewisian reference to Venus is not present in any significant way in The Magician’s Nephew.

Now Ward gets around these and other problems by claiming that Lewis didn’t always follow the plan: “Nevertheless, for all its apparent ungraciousness, we can bear in mind that Lewis was unlikely to have been perfectly successful in carrying out his own plan” (p. 233). But if Lewis didn’t follow the plan, one questions what kind of “plan” it was.

Hope, Love, and Faith (photo: Anthony Dekker)

In his story “The Honour of Israel Gow,” G. K. Chesterton writes: “I only suggested that because you said one could not plausibly connect snuff with clockwork or candles with bright stones. Ten false philosophies will fit the universe; ten false theories will fit Glengyle Castle. But we want the real explanation of the castle and the universe.” In that spirit, I offer an alternate theory (the core of which was developed collaboratively) which I also blogged about more than a decade ago. Not that I think that my theory is necessarily right, just that it’s a better theory than Ward’s, and therefore casts doubt on his proposal. A theory should, after all, explain the facts better than any alternative theory.

And my theory is this: that the seven Narnia stories are linked to the Seven Virtues: Love, Faith, Hope, Prudence, Temperance, Fortitude, and Justice. This fits what we know about composition. Of course, if you thought you were writing just one Christian children’s book, it would be about Love. Of course the next two books written would be about Faith and Hope. Of course the four “cardinal virtues” would come last. So how does this work?

I get 11 “hits.” That’s 11 out of 25, because I discarded 5 options while producing the chart, but the match is still extremely significant, with p < 0.04%. Shields are a common Christian symbol of Faith (Ephesians 6:16) and they are mentioned especially often in Prince Caspian, which I associate with that virtue (and see also the line “We don’t forget. I believe in the High King Peter and the rest that reigned at Cair Paravel, as firmly as I believe in Aslan himself.”).

Anchors are a common Christian symbol of Hope (Hebrews 6:19) and they are mentioned especially often in The Voyage of the Dawn Treader (and see also “But Reepicheep here has an even higher hope… I expect to find Aslan’s own country. It is always from the east, across the sea, that the great Lion comes to us.”). The Horse and His Boy is full of bravery in the face of fear, i.e. of Fortitude (e.g. “And now at last, brave girl though she was, her heart quailed. Supposing the others weren’t there! Supposing the ghouls were! But she stuck out her chin (and a little bit of her tongue too) and went straight towards them.”).

The Silver Chair has Puddleglum to demonstrate Prudence, and the final judgement in The Last Battle demonstrates Justice. It is really only for The Magician’s Nephew that I have failed to make my case, but there one can take Uncle Andrew and Jadis as examples of the absence of Temperance (as in “… he thinks he can do anything he likes to get anything he wants.”).

Hope and anchors have a long association. This flag was embroidered by Jane, Lady Franklin for one of many expeditions searching for her lost husband (photo credit)

To quote Chesterton again: “Ten false philosophies will fit the universe; ten false theories will fit Glengyle Castle.” Another theory for the Narnia books that has been suggested to me is that they correspond to the seven liberal arts, with the first three books written corresponding to the Trivium (Grammar, Logic, and Rhetoric, in that order) and the last four books written corresponding to the Quadrivium (Arithmetic, Geometry, Music, and Astronomy).

We can count words as before, except that the category “long words” (corresponding to Rhetoric) includes all words of 11 or more letters, such as “crestfallen,” “unmitigated,” or “waterspouts.” We get 8 “hits” this way (2 more than for Ward’s theory). Allowing for discarded options, this is statistically significant, with p < 2%. The pairings of The Lion, the Witch and the Wardrobe with Grammar and Prince Caspian with Logic are rather unconvincing, but I think that this theory is still better than that of Michael Ward.

One can even find characteristic colours in the books, with the words “green,” “white,” “blue,” and “black” occurring particularly often in The Magician’s Nephew (52), The Lion, the Witch and the Wardrobe (59), The Voyage of the Dawn Treader (26), and The Silver Chair (39), respectively.

Chesterton (or, rather, Father Brown) concludes with what is really the fundamental principle of science: “But we want the real explanation of the castle and the universe.” And I don’t think that Michael Ward has the real explanation of the Narnia books. Indeed, even if one assumes that the Narnia stories follow a plan, there are better candidates for a plan than the one that Ward suggests.

Goodreads rates Planet Narnia 4.3 out of 5, because (judging by the comments) people largely seem to believe Ward’s argument, which I find so unconvincing. However, I can really only give his book two stars:

* *
Planet Narnia by Michael Ward: 2 stars

Solar Racing Basics: Sponsorship

Click to zoom / Public domain image

Continuing the analysis of my Solar Racing Basics Poster (see this tag), the cost of logistics, and of building a car, mean that sponsorship is critical. There are three main kinds:

  • Cash sponsorship from companies
  • In-kind sponsorship (free or reduced-price products and services) from companies
  • Crowdfunding (donations)

Major cash sponsors are often acknowledged in the name of the team, e.g. Vattenfall, Agoria, or Top Dutch (the latter is a marketing campaign for the three northern provinces of the Netherlands). Alternatively, major cash sponsors can be acknowledged in the name of the car, e.g. Covestro Sonnenwagen from Sonnenwagen Aachen, thyssenkrupp blue.cruiser from Bochum, or Unlimited (Western Sydney University motto) from Western Sydney Solar Team.

In-kind sponsors often appreciate positive media coverage of the product or service, or photographs of the product or service in use.

Crowdfunding can be particularly promising when a team effectively represents a nation, region, or state, e.g. Agoria (Belgium), EcoPhoton (Malaysia), STC (Thailand), Hyadi (Mexico), or Top Dutch (three northern provinces of the Netherlands).

Click to zoom / Image credits: Anthony Dekker (Agoria’s sponsor logos on the side of their car and Western Sydney’s Unlimited 3.0 painted in their university’s colour)

To read more, see these posts from from team Arrow:

Solar Racing Basics: Logistics

Click to zoom / Public domain image

Even though the World SolarChallenge has been cancelled for 2021, I thought it worthwhile to continue the analysis of my Solar Racing Basics Poster (see this tag). There is an old military saying that “amateurs talk about tactics, but professionals study logistics.” The logistics of bringing a car and a team to Australia can be surprisingly difficult, and if you can’t do that, it really doesn’t matter how good the car is. Issues include:

  • Complexities of international freight (especially when batteries are classed as “dangerous goods”)
  • Australian customs and biosecurity regulations
  • Tickets and visas for the team
  • Covid-related regulations
  • Renting equipment and support vehicles in Australia
  • Having enough people legally permitted to drive in Australia (especially driving rental vehicles and trucks)
  • Accomodation in Australia (including tents for the Outback during the race)
  • Food in Australia (especially food in the Outback)
  • Insurance (of various kinds)
  • Other issues noted in the official Team Manager’s Guide

This comment from the Belgian team in 2017 highlights the complexity of just one issue:

“ ‘Voor mij is het de eerste keer dat ik voor zo een uitdaging sta,’ zegt logistiek manager Pieter Galle uit Leuven. ‘Het batterijpakket versturen is de grootste uitdaging voor het team. De batterijcellen die wij gebruiken zijn vaak niet toegelaten op vluchten. Om deze toch te kunnen versturen moeten er veel veiligheidsmaatregelen getroffen worden. Gelukkig heeft DHL Global Forwarding, in samenwerking met Deufol als verpakker van de goederen en batterijen alles tot in de puntjes kunnen regelen, zodat wij ons met het team volledig op het wereldkampioenschap konden concentreren.’ ”

(Translation: “ ‘It’s the first time I’ve faced a challenge like this,’ says logistics manager Pieter Galle from Leuven. ‘Transporting the battery pack was the biggest challenge for the team. The batteries we use are often forbidden on flights. To be able to send them, many safety measures need to be taken. Fortunately, DHL Global Forwarding, in cooperation with Deufol our packer, has managed all the details, making it possible for us to focus our attention on the world championship.’ ”)

To read more, see this post from Solar Team Twente and this 2016 solar car conference presentation.

Perelandra: a book review

Perelandra (1943) by C. S. Lewis (1996 cover by Kinuko Y. Craft)

Having blogged about Out of the Silent Planet and That Hideous Strength, the first and last novels of the “Space Trilogy” or “Cosmic Trilogy” by C. S. Lewis, I should also mention Perelandra, the middle volume.

While Out of the Silent Planet is science fiction, Perelandra is better described as religious fantasy (with portions of what could be called supernatural horror). However, in a 1962 discussion with Kingsley Amis and Brian Aldiss, Lewis states that “The starting point of the second novel, Perelandra, was my mental picture of the floating islands. The whole of the rest of my labors in a sense consisted of building up a world in which floating islands could exist. And then, of course, the story about an averted fall developed. This is because, as you know, having got your people to this exciting country, something must happen.” When Aldiss responds “But I am surprised that you put it this way round. I would have thought that you constructed Perelandra for the didactic purpose,” Lewis replies “Yes, everyone thinks that. They are quite wrong.

The basic idea of the floating islands of vegetation on the ocean of Perelandra (what we call Venus) may have came from the novel Last and First Men by Olaf Stapledon (XII§4), after mankind has chosen to exterminate the native civilisation of Venus (something that Stapledon seems to approve of, but which Lewis explicitly criticised in Out of the Silent Planet): “Man now busied himself in preparing his new home. Many kinds of plant life, derived from the terrestrial stock, but bred for the Venerian environment, now began to swarm on the islands and in the sea. For so restricted was the land surface, that great areas of ocean had to be given over to specially designed marine plants, which now formed immense floating continents of vegetable matter.

In Chapter 3 of Perelandra, when Elwin Ransom first arrives on Venus, there are some wonderful descriptive passages, which go far, far beyond Stapledon’s bald statement: “It seems that he must have remained lying on his face, doing nothing and thinking nothing for a very long time. When he next began to take any notice of his surroundings he was, at all events, well rested. His first discovery was that he lay on a dry surface, which on examination turned out to consist of something very like heather, except for the colour which was coppery. Burrowing idly with his fingers he found something friable like dry soil, but very little of it, for almost at once he came upon a base of tough interlocked fibres. Then he rolled round on his back, and in doing so discovered the extreme resilience of the surface on which he lay. It was something much more than the pliancy of the heather-like vegetation, and felt more as if the whole floating island beneath that vegetation were a kind of mattress. He turned and looked ‘inland’ – if that is the right word – and for one instant what he saw looked very like a country. He was looking up a long lonely valley with a copper-coloured floor bordered on each side by gentle slopes clothed in a kind of many-coloured forest. But even as he took this in, it became a long copper-coloured ridge with the forest sloping down on each side of it. Of course he ought to have been prepared for this, but he says that it gave him an almost sickening shock. The thing had looked, in that first glance, so like a real country that he had forgotten it was floating – an island if you like, with hills and valleys, but hills and valleys which changed places every minute so that only a cinematograph could make a contour map of it.

It’s a great pity that Venus is nothing like that at all.

Lewis wrote Perelandra while a Fellow at Magdalen College, Oxford.

Much of the rest of the book consists of conversations about theology and moral philosophy between Ransom, the scientist Weston (who first appeared in Out of the Silent Planet), and Tinidril, one of the two “people” on Venus. Tinidril corresponds to Eve in the Bible, so that we get a sort of alternate history of the “Temptation of Eve.” Weston is possessed by a “Force” that turns out to be Satan or a demon. As a former academic myself, it is interesting to see Lewis’s ascending hierarchy of potential moral failings:

“RANSOM: ‘Does that mean in plainer language that the things the Force wants you to do are what ordinary people call diabolical?’
WESTON: ‘My dear Ransom, I wish you would not keep relapsing on to the popular level. The two things are only moments in the single, unique reality. The world leaps forward through great men and greatness always transcends mere moralism. When the leap has been made our “diabolism” as you would call it becomes the morality of the next stage; but while we are making it, we are called criminals, heretics, blasphemers. …’
‘How far does it go? Would you still obey the Life-Force if you found it prompting you to murder me?’
‘Or to sell England to the Germans?’
‘Or to print lies as serious research in a scientific periodical?’
‘God help you!’ said Ransom.

The chart below shows a chapter-by-chapter frequency analysis of various names and words in the book (some obvious synonyms were also used in counting words, and characters mentioned but not appearing are included). There is also a chapter-by-chapter polarity (sentiment) analysis at the bottom of the chart.

When one considers the theological subject matter, the conflict with the Un-man, and the underground scenes towards the end, the novel is a little reminiscent of Dante’s Inferno, but the final chapters are far more like the Paradiso. Aspects of the conflict between Ransom and Weston recall the interaction between Frodo and Gollum in The Lord of the Rings, while other aspects of Perelandra are like visiting the Elves. It is not a simple book.

Goodreads rates the novel as the best of Lewis’s trilogy, giving it 3.99 out of 5. I’m giving it five stars, but readers not interested in theology or moral philosophy would no doubt rate it lower.

5 stars
Perelandra by C. S. Lewis: 5 stars

Out of the Silent Planet: a book review

Since Mars is on my mind right now…

Out of the Silent Planet (1938) by C. S. Lewis (1996 cover by Kinuko Craft)

C. S. Lewis is famous for the Narnia novels, but more than a decade before they were written, he published Out of the Silent Planet. Lewis was to write two sequels (I have blogged about the last volume, That Hideous Strength). However, Out of the Silent Planet is essentially science fiction, while the sequels are better described as fantasy.

Considered as a work of science fiction, Out of the Silent Planet was a pioneering novel. It followed (and was influenced by) novels by H. G. Wells, David Lindsay, and Olaf Stapledon, but preceded the work of Brian Aldiss, Arthur C. Clarke, and other British science fiction authors of the “Golden Age.” Lewis’s novel was one of the first to sound a cautious note about human colonisation of other planets. In his 1958 essay “Religion and Rocketry,” Lewis describes the rather sad results that human colonisation could have: “We know what our race does to strangers. Man destroys or enslaves every species he can. Civilized man murders, enslaves, cheats, and corrupts savage man. Even inanimate nature he turns into dust bowls and slag-heaps. There are individuals who don’t. But they are not the sort who are likely to be our pioneers in space.

Lewis’s word hnau (sentient being) was borrowed by James Blish in his alien-contact novel A Case of Conscience. In Out of the Silent Planet, Lewis brings colonisation to a halt after three deaths; Ursula K. Le Guin’s novel The Word for World Is Forest is one of many where exploitative colonisation runs its course. Several ideas in the 2009 film Avatar can be traced back to classic novels that were, in turn, ultimately inspired by Lewis.

In Out of the Silent Planet, Lewis introduces not one, but four, sentient species living in harmony with each other: the hrossa (farmers and poets), the séroni (scientists and philosophers), the pfifltriggi (artists, miners, and engineers), and the eldila (angels, essentially).

The scientist Weston actually recommends exterminating the inhabitants of the planet to make room for humans, claiming “Your tribal life with its stone-age weapons and beehive huts, its primitive coracles and elementary social structure, has nothing to compare with our civilization – with our science, medicine and law, our armies, our architecture, our commerce, and our transport system which is rapidly annihilating space and time. Our right to supersede you is the right of the higher over the lower. Life … is greater than any system of morality; her claims are absolute. It is not by tribal taboos and copy-book maxims that she has pursued her relentless march from the amœba to man and from man to civilization.” (this was an idea seriously suggested in the 1920s and 1930s, but one which was perhaps seen for what it was after World War II). The businessman Dick Devine simply wants to exploit the inhabitants for profit. Only the hero, Elwin Ransom, is interested in them for who they are.

Lewis wrote Out of the Silent Planet while a Fellow at Magdalen College, Oxford.

The science in Out of the Silent Planet is surprisingly good, considering that Lewis’s area of expertise was English literature. No doubt Lewis ran his ideas past the scientists at Magdalen College. There are some clangers in Lewis’s discussion of gravity onboard the spacecraft, and he no doubt knew that the theory of Martian canals was obsolete (although Robert A. Heinlein and Ray Bradbury were still using the idea of canals in the 1940s and 1950s). Lewis does an excellent job of explaining the impact of low gravity on Martian life, of pointing out that space is not “dark and cold,” and of describing the need for oxygen on the Martian surface.

He learned from the sorn that he was right in thinking they were near the limits of the breathable. Already on the mountain fringe that borders the harandra and walls the handramit, or in the narrow depression along which their road led them, the air is of Himalayan rarity, ill breathing for a hross, and a few hundred feet higher, on the harandra proper, the true surface of the planet, it admits no life.

Bringing in a specialist linguist (Elwin Ransom) to decipher the Martian language is a neat trick (and one repeated in Poul Anderson’s The High Crusade). Lewis’s friend J. R. R. Tolkien may have been an inspiration for this character.

Lewis’s naming of the planets. Out of the Silent Planet is set on Malacandra (Mars).

Lewis’s special interest was Mediaeval and Renaissance literature. In Out of the Silent Planet he is taking the cosmology of Dante’s great trilogy (see my discussion of the Inferno, Purgatorio, and Paradiso) and putting it through a Copernican Revolution, while retaining the Christian worldview. Naïve correspondences with Dante should be resisted, however, since Lewis was not originally intending to write a trilogy. If one absolutely must draw links, Out of the Silent Planet would probably correspond to the Purgatorio, with its emphasis on permissible vs wrongful desires.

Goodreads rates this ground-breaking novel 3.92. I’m giving it four and a half stars.

4.5 stars
Out of the Silent Planet by C. S. Lewis: 4½ stars

Solar Racing Basics: Race Strategy

Click to zoom / Image credit: Vattenfall/Nuon/Delft Solar Team

Continuing the analysis of my Solar Racing Basics Poster (see this tag), it’s important to remember that the “best” car doesn’t always win the race. The work of the strategy subteam in the “chase vehicle” is also critically important. During the race, this subteam constantly calculates the best speed for the conditions, taking into account weather, road conditions, and existing battery charge. This includes deciding where it is worth speeding up to avoid upcoming bad weather. Making the right decision can be critical – the chart below (click to zoom) summarises the Challenger Class of the 2017 World Solar Challenge:

Road distance in this chart is from left to right, and the vertical axis shows how fast teams are (higher is slower, and the faint dashed lines show specific speeds). Teams 15 (Western Sydney University) and 88 (Kogakuin) were keeping up with the leaders, but made what in hindsight was the wrong decision when bad weather loomed, losing 6 or 7 hours as a result. Making the right decision under these circumstances is very difficult, however, and relies on good weather prediction services (or, as some teams have done in the past, on taking a meteorologist along).

Click to zoom / Image credits: NASA (unsettled weather across central Australia, 2013) and Vattenfall/Nuon/Delft Solar Team (interior of their chase vehicle for the 2011 World Solar Challenge)

In the Cruiser class, race strategy also includes deciding how many passengers to carry (more points, but more weight), and how much to recharge from the grid at stage stops (more energy, but fewer points). That makes Cruiser strategy an even more difficult problem.

To read more, see this post on Challenger strategy which I wrote in 2018.