Shoot for the Moon: Would the USA’s Cold War plan to blow it out of our night sky really work? Fiona McBride

In 1958 – the year after the Soviet Union’s Sputnik became the first object to be launched into space by humankind – 60 years ago – the government of the USA began to work on a secret plan to assert their dominance on the stage of world power: by blowing up the moon. Known covertly as “project A119”, the intention was to make the military might of the USA abundantly clear to all on earth.

 Of course, the first question this raises is: would such a show of force actually be possible? Though it may look small from down here, and is supposedly made of green cheese, the moon is actually a seventy trillion megaton rock located four hundred thousand kilometers away. That’s quite a big thing to blow up, and a significant distance to send explosives. The explosion would have to have enough energy to not only break the moon into pieces, but also send them far enough away from one another that their gravitational fields – the attractive forces that act between all objects – wouldn’t be able to pull them back together. Otherwise, the single lump of geological matter we call our moon would simply be replaced by a pile of lunar rubble. It is estimated that such an explosion would be equivalent to the detonation of thirty trillion megatons of TNT; given that the Tsar Bomba – the most powerful nuclear bomb ever built – had an explosive power of fifty megatons, blowing up the moon would require six hundred billion of these. Humanity has neither the uranium supplies to build such a bomb, nor the rocket technology to get it there.

Other options include creating a “moon quake” to split apart the internal structure of the rock; this would need to be equivalent to a 16.5 on the Richter scale. The most violent earthquake recorded read just 9.5 on the Richter scale, so it’s unlikely that such a quake could be artificially produced on the moon. Alternatively, the moon could be zapped with a giant laser, however this would need to provide the same amount of energy instantaneously as the sun outputs every six minutes. Humans don’t really have the resources to power such a thing.

 It seems, therefore, that blowing up the moon to assert their dominance over the space and nuclear spheres wasn’t really an option for the USA in 1958 – or even sixty years later – due to a lack of both technology and resources. However, the idea of blowing a large crater in the moon, in order to produce a giant explosion to demonstrate to the world the might of the USA, and leave behind a crater visible from earth to remind them of it forevermore was also considered. This, too, was dismissed in 1959; the reasons for this are not clear, but perhaps those in charge of the project realised how utterly ridiculous their own idea sounded.

 But let’s just take a step back for a moment, and imagine if exploding the moon were possible: what would the consequences be here on earth? Would lumps of moonrock kill us all? What would life be like on a moonless planet?

So the moon has exploded. The first thing most humans notice is a big, bright cloud spreading out through the sky where the moon used to be. This is the light from the explosion illuminating the moon debris. Dust then covers the sky for a while, making daylight darker and air travel impossible for a few months. Our seas and lakes are still tidal – the sun exerts a gravitational pull on the earth that contributes to this, but does not move relative to the earth – so there will be no spring or neap tides – the water will rise to one-quarter the height of a spring tide and return to the same lower level each day. Fragments of moon start to fall to earth; some burn up as they enter our atmosphere; others hit the ground and wreak havoc where they land, though it is unlikely that this would be catastrophic for humanity, as they would move slowly in comparison to other astronomical objects that fall to earth, such as asteroids.

 Once the dust clouds have cleared, the next noticeable thing is a lot more stars. The moon is by far the brightest object in the night sky, so with it out of the way, nighttime will be darker and the stars much brighter by comparison. One –or more – smaller ‘moon replacements’ may also appear in the sky, if the explosion leaves some larger chunks of rock as well as debris and dust. Of course, this debris and dust continues to rain down on the earth whenever a piece falls out of orbit.

 Only after the majority of this debris has cleared – in perhaps a few thousand years – is the next major effect noticeable by humans: the earth will tip over. Gravitational interactions between the earth and the moon are what is currently preventing this; without it, the earth will tip on its axis, causing the poles to melt and an ice age to occur every few thousand years on whichever part of the planet is furthest from the sun at that point.

 So, although exploding the moon isn’t really possible – and certainly wasn’t in the 1950s – it wouldn’t have utterly catastrophic consequences for the earth, just bring significant change. However, as a show of force, it still seems somewhat excessive.

 

When can I live on the moon? Fiona McBride

Every civilisation that has ever existed on earth knew about the existence of the moon, long before any of us knew of any other civilisations and landmasses. So why aren’t we living there yet?

 The biggest issue preventing ancient – or more modern – civilisations from settling on the moon is the difficulty associated with getting there.  Despite millennia on earth, humans only made it to the moon in 1969, and we certainly didn’t get there in a boat. Indeed, travelling to and from the moon is still a significant barrier to colonisation: the Apollo moon mission cost an equivalent $107 billion in today’s money. However, massive advancements in aerospace technology have already reduced projected costs for getting humans to the moon, and shaved the time taken to get there down from three days to less than one day.  So, if humanity decides to focus on advancing this technology and making it cheaper, we could be on regular flights to the moon in just a decade or two.

 But getting there isn’t the only challenge to life on the moon: once we arrive, we have to survive. The moon has no atmosphere, so the fluffy blanket of air that keeps us on earth away from the majority of the sun’s deadly ultraviolet radiation and insulates us from the worst of the sun’s heat and the universe’s cold just isn’t there. This means a daily temperature range of -233 – 123 degrees centigrade, and killer sunburn during the hours of daylight. No atmosphere means no weather, but the moon still experiences frequent storms consisting of micrometeroids – tiny space rocks – that can be as large as golf balls. Earth’s atmosphere is also the ultimate reason that life exists on its lands and in its oceans: it provides oxygen. In order to survive on the moon in the longer term, we need to conquer all of these challenges. A smart way to do this might be to send robots and building materials ahead of the first human colony, so that the settlers could move into pre-built airtight pods providing oxygen and protection from the harshness of space. This isn’t so far beyond the current technological abilities: we already have lunar rovers capable of mapping out a suitable site for a moon settlement, and robots capable of construction, so the main challenge is again developing a cheap and efficient means of space travel to get these robots and building materials to the right place.

 Even with more efficient space travel, taking all of the resources necessary for longer-term human survival with us from earth just isn’t sensible or economical.  Evidence of ice has been found on the moon, and it has been hypothesised that there may be large amounts of water stored within its structure, however whether or not this is correct, and how to extract the water if it is there, need to be determined before any concrete plans for settlement are laid. Depending how much water there is, we either need to develop a means of splitting the H2O molecules to make pure oxygen, or find a way to extract the 40% oxygen from the sharp dust coating much of the moon’s surface. Additionally, surveys must be conducted to find out what other resources the moon has to offer – can we grow plants there? Is there something that could be used as fuel? Can we harness some of the heat from the active volcanoes as an energy source? Can we create some kind of atmosphere that will support tree growth, so we can recycle our air? This aspect of lunar colonization is probably the one we know least about at the moment, so we’re looking at a decade or two for those lunar surveys, plus some time to work out the chemistry involved – maybe thirty years total if humanity puts some thought towards it.

 So what will it be like to live on the moon, if and when we eventually get there? Well, given the killer ultraviolet rays, the extreme temperatures, and the micrometeoroid storms, you’ll probably want to send most of your time inside whatever the robots have built. The transmission rate for messages between earth and the moon is around one second, so it’s likely you’ll have wifi up there to keep you entertained. In terms of employment, there’s plenty of potential for science in and out of the settlement buildings, as well as lunar geography and geology, and even space photography. The new settlement will also need doctors, although anyone in need of specialist treatment will probably need to be shipped back to earth. There also remains much to be discovered about the effects on the human body of living in a low-gravity environment; anyone moving to the moon must bear in mind that they will essentially be a test subject for this.

 So, it seems that if we were to focus our collective scientific and creative minds on the subject, humans could be moving to the moon in as few as thirty years. But should we be putting energy into moving to the moon, instead of on limiting the damage we’re doing to our own planet? Space travel has led to the invention of a whole range of useful technologies – from CAT scanners and artificial limbs to Velcro – however if research and resources required to move us to the moon were instead dedicated to thirty years of increasing sustainability and promoting global development, perhaps staying on earth would become a more attractive option.

Clearing Up Our Space Junk – Matt Jones

Over the last sixty years or so, space exploration has been at the fore of the public’s imagination, and our desire to learn more about the universe we live in has led to the advancement of space technology. This has resulted in many test launches and experiments, during which a whole array of spacecraft and satellites have been sent into space. Consequently, we have slowly been contributing to an ever-growing jumble of junk that is now orbiting Earth. Although it’s out of sight, the University of Surrey are working to make sure that it is not kept out of mind. Later this year, they are launching a spacecraft on a mission called RemoveDebris, which will hopefully do exactly what is says on the tin before burning up into flames.

Broadly speaking, the term “space junk” refers to any man-made object in space that no longer serves a useful purpose. This definition encompasses objects such as used boosters, dead satellites and even Elon Musk’s Tesla Roadster, a sports car owned by the CEO of Tesla and SpaceX, which was used as a dummy payload for the test flight of the SpaceX Heavy Falcon earlier this month. Even though the car is technically space junk, it is following an orbit around the sun and so it poses little cause for concern. Unfortunately, the same cannot be said for the 7500 tonnes of junk that the European Space Agency have estimated orbits the Earth.

Having so much debris orbiting the Earth is a problem because even the smallest objects can cause a lot of damage. In 2016, a fleck of paint chipped a window on the International Space Station (ISS), which regularly has to move out of the way of bigger pieces of junk. Furthermore, a piece of junk just 10 centimetres long could devastate a satellite. This could have detrimental effects on communication and weather forecasting, making clearing our cluttered low orbit environment a joint responsibility.

Another dangerous aspect of the debris is the potential for a cascading collision effect known as the Kessler Syndrome. This is a scenario triggered by the collision of two large objects that then cause a self-sustaining chain reaction of collisions, producing more debris. The large inactive satellite Envisat, which is owned by the European Space Agency, has been listed as a potential trigger for a Kessler event. It weighs roughly 8 tonnes and it passes within 200 metres of two other pieces of catalogued space junk every year.

Research into ways of clearing up our space junk is therefore of immediate relevance and we will hopefully be able to learn a lot from the RemoveDebris mission, which is being led by the Surrey Space Centre at the University of Surrey.

The small RemoveDebris spacecraft – the size of a washing machine – was shipped to the Kennedy Space Centre in Florida in December. It will be launched into space later this year on a ISS resupply mission. Once at the ISS it will be unpacked by astronauts and deployed on its mission to experiment with techniques in which debris can be collected and removed from orbit.

In the first scheduled experiment a cubesat (a miniaturised satellite used for space research) will be ejected from the spacecraft. A net will then be ejected from the spacecraft to ensnare the cubesat. The development of this kind of capture technique could lead to space junk being hauled out of orbit by spacecraft in the future. The heat upon re-entry to the Earth’s atmosphere will cause the space junk to burn up.

The second capture experiment is due to test a harpoon system. In this experiment, a target, made out of the same materials as satellite panels, will be extended out by the spacecraft. A harpoon will then be fired at the target. If a successful hit is made, this will be the first harpoon capture in orbit.

The third experiment will test vision based navigation. In this experiment, another cubesat will be ejected from the spacecraft. Cameras on-board the spacecraft will be used to collect data, which will then be sent to Earth and processed on the ground. If successful this will validate the use of vision-based navigation equipment, and ground-based image processing, in the context of active debris removal.

Finally, at the end of the mission, the spacecraft will deploy a large drag sail. The sail is made out of a reflective material and uses radiation pressure exerted by photons of light from the sun to produce thrust in a phenomenon known as solar sailing. The sail will cause the spacecraft to gently de-orbit before it violently burns up upon re-entry into the Earth’s atmosphere so that, crucially, it doesn’t become space junk itself.

Whether the RemoveDebris mission is a success or not, it is important that we keep the ball rolling into the future. Clearing up our skies is a collective responsibility between governments and space agencies as the consequences of an essential satellite being damaged, or space missions being grounded, will affect us all. Space exploration has an inexhaustible ability to inspire and thrill us, so let us not call time early on this journey simply because of our inability to look after the planet we live on.

 

The Northern Lights – Naomi Brown

At the beginning of November, residents of Scotland and Northern England were
able to view a dazzling light show in the sky: the Northern Lights. But what
causes them and how can we predict when it will happen again?
The Northern Lights are a natural phenomenon where brightly, coloured lights
are seen across the night sky in the appearance of sheets or bands. They are
generally seen close the magnetic poles in an area called the ‘auroral zone’. The
best time to spot the auroras is when the Earth’s magnetic pole is between the
sun and the location of the person observing. This is called magnetic midnight.
The Northern lights are caused by gaseous particles in the Earth’s atmosphere,
colliding with charged particles, released from the sun’s atmosphere.  The
charged particles are carried towards Earth by solar winds. The particles are
deflected from the Earth’s magnetic field. However, at the poles, the field is
weaker allowing a few particles to enter the atmosphere. Hence this is why
auroras are more likely to be seen close the magnetic poles; making Iceland and
Northern Scandinavia common destinations for travellers searching for the
Northern Lights.
The colours of the Northern Lights are dependent on the type of gas molecule
involved in the collisions. Green is one of the most common colours seen and is
caused by collisions of oxygen molecules, whereas blue or purple auroras are
caused by nitrogen molecules.
Why can the northern lights sometimes be seen in places further from the
Earth’s poles e.g. the UK ? The answer is the spread of aurora oval due to
ageomagnetic storm. Geomagnetic storms are more common after the maximum
in the solar cycle, a repeating 11-year cycle. The most recent solar maximum
was in 2013.
The Northern Lights are notoriously unpredictable. There are many forecast
apps available such as “My Aurora Forecast”. One of the best websites to check
out when the auroras will be visible from where you are is the Aurora Service
(www.aurora-service.eu/aurora- forecast/). The site gives the Kp value
predicted for the next hour by using solar activity data obtained from a NASA
spacecraft, ACE. The ACE orbits 1.5 million kilometres from Earth: the prime
position to view the solar winds.
A common way to represent geomagnetic activity is the Kp index. Magnetic
observatories located all over the world use instruments to measure the largest
magnetic change every three hours. The recorded data from all these
observatories is averaged to generate Kp values, which range from 0 to 9. The
larger the value the more active the Earth’s magnetic field is due to geomagnetic
storms and the further the aurora oval spreads. If the Kp value is above 4, then it
is storm-level geomagnetic activity. These Kp values are useful in predicting
when auroras will be visible. To see the aurora from the UK, the Kp value would
have to be at least 6.

To get a great show, the conditions are important. Clear nights with no clouds
are best. It is also worth checking the moon cycle: the brightness of a full moon
drowns out the lights of aurora.