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Tuesday, 18 October 2016

Video round up on Schiaparelli and the Trace Gas Orbiter

Above: Mars.
Update: As of 18:00 GMT the TGO orbiter is safely in Mars orbit, but the lander seems to have vanished...

'Schiaparelli and the Trace Gas Orbiter.' It sounds like an experimental Italian jazz band doesn't it? It's actually a ground breaking European mission - part of a small fleet of them, titled 'ExoMars.'

The European Space Agecy has gotten spacecraft into orbit around Mars before, and on one occasion a British team tried to put a lander onto the surface - it was never heard from again, although it was found by the MRO spacecraft last year

But they've never managed to get a working lander on the surface - yet. This afternoon they hope to change that.
ESA is aiming to land a rover and an automated science platform in the early 2020's. That's where the Schiaparelli lander comes in: Although it's science payload is modest, it will give ESA a chance to practice getting something safely onto Martiian soil. 

Meanwhile the Trace Gas Orbiter will do a double mission, studying Mars' atmosphere (and looking for any biomarker gases like methane in particular) and acting as a relay satellite for future missions.
But don't just take my word for it* - take these ESA video's word for it instead.

The descent to Mars: 


The mission's milestones:

A flyover of the landing site:  

The lander should (hopefully) be on the surface by 1500 GMT. You can follow the landing live, here.

*Because I'm some random on the internet.

Monday, 17 October 2016

Answers for Authors: How do I conquer another planet?

How do I conquer another planet?

I have assumed that the asker is researching for a book they are writing. 

Although... they didn't specify that they were

So my back up assumption is that they don't have the means to carry any of the following out.

If I'm wrong... er. Sorry everyone?

Anyway: The only inhabited planet we have to use as a model for conquest is Earth, so let's approach this from the the perspective of an extraterrestrial looking to invade.
I'm the alien. I'm considering investing in a fleet of massive space battlecruisers, possibly even a Death Star or two. Terrifying bioweapons might be on my mind.


But... that's not what I actually need.

Why? Well, what will make the governments of Earth capitulate to my evil alien overlordship? And can I find a  method doesn't involve breaking my budget, because I'm fiscally responsible as well a pure tentacled evil? 

In fact... yes. There is a very simple method, one which mother nature herself has tried and tested. In fact it's so easy to do  the humans might just figure it out for themselves and blow their own planet up with it

I can just drop rocks on them.

'It can't be that simple' you're thinking? Well have a look at this feasibility study, prompted by NASA and being carried out by Made In Space Inc: They're looking at sending 3D printers to asteroids and turning the asteroid material into crude mechanical parts. Slowly, they could convert the asteroid into a huge (if basic) unmanned spacecraft. It could be very simple, and literally be powered by large springs - all because it doesn't need to climb any steep gravity wells like a ship leaving Earth does. 
Once converted it would gently steer around the solar system under commands from Earth*. Here's their concept design:

It would mean some major advances in 3D printing, but nothing unbelievable - Made In Space have already pushed the 3D space envelope, launching a 3D printer to the International Space Station and making tools with it there.

So far, so 'aint-it-cool'. But, while throwing 3D printing into the mix is new, there have been a lot of (fairly realistic) ways to change an asteroid's or comet's course already studied. To name just a few you could:
And these aren't just theories: NASA is, right now, in the process of designing and building a space mission that will  park an asteroid in an orbit around the Moon. Astronauts will explore it, and practise for missions to the moons of Mars.

Because it's pretty: Mars.

I'd say a steerable asteroid looks pretty possible with merely human technology.

That's great for the invasion: A tame asteroid would also make one hell of a weapon of mass destruction. Tens to millions of times the blast of a nuke, but no radioactive fallout. From cuts and bruises in Chelabinsk to the extinction of the dinosaurs, mother nature has given us a blueprint for a terrifying weapon.

As an invading alien, I've got technology centuries ahead of present day humanity's to work with. I also have lots of time, and lots of space rocks: The main asteroid belt has over 200 asteroids larger than 100 kilometres and 750,000 asteroids larger than 1 km. 

The Kuiper belt beyond Neptune contains thousands of icy objects over 100km wide, and trillions of smaller comets. With enough time I can weaponise almost all of them

As we looked at in 'What if the biggest NEO was going to hit us?' the human race would be stretched to knock aside any asteroid much bigger than 10 km on short notice. Once I've made a few thousand of them dance the fandango in Hubble's field of view** - or flattened a couple of cities with some smaller asteroids - humanity would face a stark choice: Surrender to me unconditionally, or face the end of life on Earth. Because I could literally pummel this planet to the point of sterilisation.

Comet 67-P would nicely

Brute power isn't the only advantage over an invasion with ships and troops: Humans do in fact have some weapons for in-space combat. But an invader who can throw half the asteroid belt need never come within range of a human jammer, kinetic impactor, or ASAT missile***. 

So to invade another planet - at least at Earth's sort of tech level - threatening to drop rocks seems far easier than  invading Star Wars style.

That's not the scary bit. The scary bit is how close humans are to having this ability ourselves. A weapon with many times a nuke's punch but  none of the radiation? We might see humans threatening each other with them long before we meet any aliens smart enough to do it.

* Because what could wrong with that?

** Not literally, because I'm an alien with no idea what the fandango is.

***By the way, I apologise to the scriptwriters of the first Independence Day movie: Their one original bit of plot - attacking the alien mothership with a computer virus - wouldn’t work: They’d never need to get that close to Earth. Not that that spoils the flim in the slightest – I have made gifs of Will Smith punching that alien on an endless loop, because I have a simple and violent sense of humour, as would, I suspect, the real aliens bombing us with remote controlled asteroid would.

Wednesday, 12 October 2016

The Universe in 101 words: How could life-like chemistry come from asteroids?

Image: A piece of meteorite, shot through with gem quality Olivine. Meteorites like this could only have come from worlds with molten cores, and geological activity - which means heat.

When the solar system was young and hot (and Donald Trump probably wanted to grope it) liquid water, melted from interstellar ice, seeped through the rocks of planetary embryos. It soaked carbon based molecules there... and changed them.

Most of those worlds died in giant collisions, and today the rubble falls as meteorites - and in them we’ve found the chemical components of DNA, proteins, and more. Lipid molecules, found in these meteorites, form into self replicating protocells in water - a clue to how life started perhaps. 

The road from chemistry to life might well have begun in space…

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Image: These dark masses are Bok Globules - clouds of gas and dust that cocoon growing star systems. The background is the thinner hydrogen gas of a nebula, heated to glowing by nearby stars.

Monday, 10 October 2016

Answers for authors: What would a battle in orbit be like?

Above: A full solar eclipse, seen from space. It has nothing to do with battles in space, it's just cool.

"What would a real battle in orbit be like?"

There are two ways to think about this question*:

What would two nations of Earth fighting in space be like?

What would Earth fighting off an invasion from extraterrestrials be like?

Let's look at the first one this post and save the alien invasion for next time - although bear in mind that much of what we're about to look at could apply to aliens with similar technology levels to Earth's.

As far as I can find out** no armed confrontation has ever taken place in space.  But there has been a hell of a lot of military activity in Earth orbit, and the information released on it gives us some material to work with

Why fight in space?  
Everything that gives modern western forces their technological and tactical edge uses space-based systems: Drone surveillance, Reaper drones, battlefield communications, guided smart bombs... even tanks depend on satellites. The images of Russian troop movements around Ukraine came from them, and the weapons that destroyed Saddam Hussein’s military wouldn’t have hit their targets without them
Even presidential phone calls rely on a small fleet of them — the Advanced Extremely High Frequency constellation

What kinds of examples can we look to?
Since it's a real field of warfare today, we have something to base our pace battle on - and a motivation for it: Dominate space and you can dominate the air, the land, and the sea. 
It's easier to find information on older military operations in space, so let's start with some fairly odd gems from the cold war:: 
  • The Soviet Almaz space station, built to orbit over American territory and take pictures, was fitted with an R23M cannon, in case any sneaky Apollo astronauts decided to board it and leave the cosmonauts hogtied with gaffa tape like floaty space pinatas. The design was abandoned, as the gun's recoil during test firings kept changing the space station's orbit.
  • Ronald Reagan initiated the 'Star Wars' program (officially called the Strategic Defense Initiative) - essentially a series of satellites and ground bases toting various advanced weapons - never really produced much, as the idea was way ahead of the era's technology. But it laid a lot of foundation for future military missions.
  • In the 1950's and '60's the US experimented with using nuclear weapons to wipe out enemy satellite arrays – a nuke produces no shockwave in space, but emits a pulse of rapidly changing electric and magnetic fields that cook the chips of any computer caught in the blast radius. The tests, called operation Fishbowl, were so successfully they created a miniature aurora, and took out six satellites... as well as most of the electronics on the island of Hawai below.
  • The Space Shuttles, those great symbols of peaceful American space exploration, were re-designed (on the insistence of the National Reconnaissance Office) to fly on highly secret military missions, often with military crew. On one occasion astronaut Ken Mattingly, who was also a rear admiral by the time he retired, was ordered to file false flight plans and travel documents to cover up taking the shuttle on a secret mission. 
In more modern times, and since the retirement of the Space Shuttle, in-space military shenanigans seem to have become more oriented around robotic missions. I say 'seems' because the world's military leaders aren't keeping me up to date on their deep space black ops for some reason. Even so, since tracking satellites and spaceships is a hobby anyone with a telescope can do, we know it still goes on:
  • The Russian satellite known as Kosmos 2499, and Object 2014-28e, was launched on a rocket meant to be carrying three communications satellites. Only later was it revealed to have been carrying 'object 2014-28e' as well. Once in orbit the mysterious satellite did something very odd: It chased down other Russian space satellites, and rendezvoused with the spent booster stage that placed it into orbit.  
  • US air force has been operating its small fleet of Boeing X37B unmanned mini-shuttles since April 2010, smashing records for length of time spent in space, and performing "classified missions in support of long term goals". It is certainly possible an X37B could chase down a satellite and damage it with a weapons in its payload bay.
  • In 2008 the Chinese decided to fly small satellite, called BX-1, close to the International Space Station. It then performed a mission in the space around a Chinese space station that had many of the hallmarks of an anti-satellite weapon test.
Is that a Virgin Galactic launcher, or a missile? The truth is it all depends on where you aim it, and Richard Branson is building a fleet of these so... be nice to him, OK? No stealing his lunch money or anything like that...
The problem is that there are also many totally peaceful uses for satellites that can do these things – for years space agencies around the wold have been developing small satellites that could rendezvous with, refuel, repair older satellites, and safely de-orbit dead ones. But as Bob Christy’, who used to track Soviet spy sats for the US, told Financial Times magazine:
“People talk about them being inspectors, but if you have the ability to manoeuvre up to another satellite in space to inspect it, you also have the ability to destroy it.”
Putting up a fight:
To add some defence to this potential space offence, Princeton university (among others) think it's certainly possible to fit countermeasures to satellites: Better manoeuvring thrusters, jamming devices, decoys, or even cannons like the old Soviet Almaz space station, are all rumoured to been tested. And a report (linked here), dating from the Reagan administration, lays out the approaches being considered at that time - including laser and particle based beam weapons.

A real incident to work from?
There has been an incident where one nation's anti-satellite weapon (accidentally) destroyed another nation's spacecraft: On January 11 2007, 865km above the Chinese mainland, a weather satellite was blown to smithereens by a missile fired from the Xichang spaceport. More than 2,300 pieces of shrapnel— each lethal to anything it hit — were released into orbit. Think a small version of the orbital debris storm in ‘Gravity’.

If you just went 'what?' go and watch the movie 'Gravity'. Go on, this is a blog post, it's patient. 

Done? Like that, but smaller – more of a space squall than a storm - but it took out the Russian BLITS satellite.

In effect the incident was ignored - and BLITS was so small and inexpensive the worst Russia was likely to do was sue. But it's a salutary lesson: A full on battle in Earth orbit would have a huge potential for collatoral damage

Sooner or later, every space fairing nation would lose.

Fighting in space and cyberspace:
But there's an element here that we're missing: Although blowing up or sabotaging enemy satellites is fun, cool, and looks great on your CV, the most energy efficient way to shut them down is to hack them.  Where it can be done not only can you deprive an enemy of the satellites use you can use it to send them misleading data – although you might want to hold off on the satellite readings of flying Scotsmen with laser powered bag pipes, for fear of giving your game away a wee bit.

A recipe for a realistic space battle?
So we know there is some gearing up being done, and the elements for an in-space battle are there -  but it looks like a battle in space isn't likely to be much like Star Wars, with space ships close enough to see each other exchanging bright beams of energy. Instead, some general possibilities seem to be:  
  • Nothing would happen for ages, and no other vehicles would be visible. Then you'd explode - hit by a missile, or debris moving too fast for the human eye to see, fired from the ground or another craft too far away to see. 
  • ASAT missiles would be fired at those craft in a low enough orbit to be hit, and clouds of debris (intentionally released and just from casualties) would pose a constant threat. If the battle went on for long enough, eventually just being in orbit would be seriously risky.
  • There might be chases, as a saboteur satellites tried to close with a target. Both would, again, be too distant for human eyes to see for most of the chase. The target might defend by trying to manoeuvre away, jam the attackers signals to ground, deploy decoys, or perhaps even use physical weapons like Almaz's  cannon to shoot it's pursuer to bits.
  • There could also be standing decoys, designed to fool ASAT weapons into hitting a worthless target, being deployed ahead of the battle.
  • Satellite constellations, ground stations, and other spacecraft like the X37B, would be trying to jam each other electronically
  • In an all out conflict nukes would be being set off as EMP weapons.
  • Hackers, probably working from the ground, would be trying to take control of, and subvert each others satellite networks 
Above: An X37B being checked after landing. The HazMat suits are because the hydrazine used in it's manoeuvring system is toxic by the way.  At least... I assume that's what it's for. Imagine if you farted in one of those things.
I'm not a soldier - so all I can say is that this is a possible image of war between modern day human forces in space. All of it would be trying to gain advantages for air, sea, or land forces. It would be battle of silent, often almost invisible and instantaneous, destruction. It would be largely fought between robotic satellites and remote controlled spacecraft, responding to pre-programmed instructions, or general commands from ground bases - Human reflexes and co-ordination simply aren't up to the speeds and distances involved, once vehicles got close to each other. The best thing a manned vessel in orbit could do is return to Earth immediately - out there it would be nothing more than a target.

But what about the green four eyed elephant in the airlock? What if we had to fight off an extra-terrestrial invasion?

I'll save that for next week.

*That's a big ol' lie,  there are zillions,  but keeping it to the two that pop into my brain fastest keeps the post to a readable length,  and gives us a blog sized entry to the topic. 

**That doesn't mean it's never happened, just that it was kept quiet if it did. 

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Tuesday, 4 October 2016

The Universe in 101 words: How could asteroids have liquid water?

4.5 billion years ago a swirling disk of dust orbited the newborn Sun, like an entourage around a pop princess*. 

The dust clumped, forming bigger and bigger objects - first fist sized, then asteroid sized, then hundreds of planetary embryos. Big ones had the gravity to pull in small ones, the impacts released heat, and everything was loaded with heat producing radioactive elements...

... so even tiny worlds, that are dead rock and ice today, were warm enough for molten cores, magnetic fields, volcanoes, tenuous atmospheres… 

…and, seeping through their rocks, the thing NASA is scouring the cosmos for: Liquid water.

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Sunday, 2 October 2016

Answers for Authors: What if the biggest NEO was going to hit us?

One use I put my physicist training to is answering questions sci-fi authors.  

I mean, the PhD has to be useful for something, right?
Following the impact of a spectacular meteorite in Australia on Tuseday, I thought I'd share ths one, and an abridged version of the write up* for it:
"What if the biggest NEO was going to hit us, and we only found out 16 months before impact?"
The biggest Near Earth Object is a 30km wide iron and stone asteroid by the name of 1036 Ganymed. That’s 125 times bigger by volume than the dinosaur killer, so we’re all in for really bad day if it hits Earth. 

Although only quite briefly, as the blast would actually boil oceans. 

Luckily for us it’s not on a collision course, as long as it stays on its current orbit. But what if something changed its orbit? What could we do?** I'd compile a list of what we should do, and send it to Bruce Willis:

"Dammit to hell John, why do you keep sending me weird lists about stuff?"

1: Do some recon.
Ideally you'd want to scout it with an unmanned, like the NEAR probe. But time is very short, so world wide scutiny using the biggest telescopes and radar dishes will have to do. 

2: Understand the 'enemy'. 
We actually already know 1036 Ganymed pretty well. It’s an S-type asteroid, composed of stone, iron, and possible certain amounts of other metals. It has an elliptical orbit that ranges from just outside Earth's to between Mars and Jupiter, and isvinclined at quite a high (26 degrees) angle to Earth’s. We don’t know if it’s a rubble pile or a solid rock, so we need to be careful how much force we use - giving any part of the asteroid more velocity than it’s escape velocity (which is estimated at about 19 meters/sec) risks shattering it, and turning one dangerous object into many without altering their overall course.

3: Work out the best way to move it:
NASA’s most realistic option for diverting an object greater than 500 meters across, with a short prep time, is good old nuclear weapons. 

Why? They pack a punch, they’re a well understood technology, and we have plenty of them. Bombs could be launched to intercept the asteroid, using heavy-lift rockets like the Atlas V, or NASA’s SLS booster. Set off with a proximity fuse, they wouldn’t need to land or match speeds with the target -  just get close and go off. 
The idea is very similar to a nuclear bomb driven engine called an 'Orion drive’ that was designed (and tested on a very small scale) in the 1950’s:

Above: The 'hot-rod',  a miniaturised prototype of the Orion launcher.

Do we have a 'go to' model for this situation? Unfortunately all of the modelling efforts I’ve been able to find have looked at moving much smaller asteroids than Ganymed. In fact one source says:
 “Devices in the nuclear stockpile have equivalent energy releases of megatons of TNT, but NEOs larger in diameter than about 10 kilometers are likely to require larger explosive energies, a regime for which devices have not been tested or simulated“ 

So we’ll have to take their conclusions about moving smaller asteroids, and scale things up in as reasonable a way as we can.

4: How much do we need to move it?
To change Ganymed’s course we need to change its speed. How much by? This is kind of a ‘how long is a piece of string‘ question, as Ganymed has been diverted onto a fictional orbit. But we can try and come up with some ball park figures, and get a rough idea – something plausible. Luckily for us there’s a very convenient simulator run by NASA/JPL, where you can see what various pushes and pulls on an Earth impacting asteroid would do. Here’s the link to the simulator. 

It only gives us the option of a few pre-loaded Earth impacting asteroid orbits to play with, none of which exactly matches the orbital parameters for Ganymed. But, since we’ve altered Ganymed’s orbit, an orbit that is close to Ganymed’s and hits Earth will do – and there is one like that (Sim8 on the menu, which has similar orbital period, semi-major axis, and eccentricity). If you’d like to have a go yourself here’s a link to Ganymed’s orbital parameters.  

In general the earlier you can get the shove in, the better.  If we could get there about 1500 days before impact we’d need to change Ganymed’s velocity by 1cm per second (against its direction of motion), to get it to miss Earth. Catch it an orbit earlier and that number drops to 0.4 cm/sec, and two orbits earlier gives us 0.3 cm/sec. 

But it’s going to hit on this orbit -16 months is less than half an orbit away. If we have to wait until it’s a year out - which is likely because armadas of bombs and rockets take time to build - we need 10 cm/sec for a miss.  Wait until 6 Months out and we need to give it 40cm/sec 

Someone with a better grasp of orbital mechanics than me might be able to get the 6-month scenario down to 20cm/sec. But I’ll be genuinely surprised if someone can budge Ganymed enough with 1cm/sec delta V so close to Earth (don’t let that stop you trying though, being wrong teaches me more!).
That doesn’t sound so bad, does it? 40 cm/sec is a granny’s shuffle. 

Granny, however, doesn’t weigh over a trillion tons. Not even a really big granny.

5: How much we actually can change Ganymed’s velocity, using nukes?
To quote ‘Defending Planet Earth: Near-Earth-Object Surveys and Hazard Mitigation Strategies:

...The high efficiency of the deposition and relatively deep penetration of neutrons reduce the necessary neutron yield to near 100 kilotons of TNT-equivalent.... To understand the action of a standoff nuclear explosion, and its ΔV capability, a member of the Mitigation Panel (David S.P. Dearborn, Lawrence Livermore National Laboratory) simulated the effect of a nuclear standoff detonation on homogeneous 1-kilometer-diameter NEOs with densities between 1.91 and 1.31 g/cm3. In these numerical models of a standoff burst about 150 meters above the NEO’s surface, about 40 seconds after the burst the NEO’s speed change ranged from 2.2 to 2.4 cm/s..... The minimum speed change for a highly porous NEO is controlled by the amount of totally vaporized material. In these models this minimum ΔV is about 0.8 cm/s for an explosion with a strong neutron output.
So for 1 km diameter object a 100 kiloton nuke, detonated at a range of 150 meters, will change its speed by 2.2 to 2.4 cm/sec. Ganymed has roughly 39000 times the mass of a 1km asteroid, so to get the same 2.4cm/sec change in velocity, we need around 39,000 100kt nukes! And, if it's a porous rubble pile, even that only gives us 0.8 cm/sec.

We could be in trouble here...

6: Start to panic and look for a really huge bomb.
We badly need to up the ante: Let’s build and field copies of the Soviet ‘Tsar Bomba’- the biggest nuke ever detonated, and use its never tested 100 megaton configuration. 100kt = 100,000 tons TNT equivalent, 100MT = 100,000,000 tons TNT equivalent, so the Tsar Bomba is 1000 times more powerful than the bomb in the initial calculation. 

Let’s assume that, using the right positioning above the asteroids surface, we get roughly 1000 times the thrust from that 1000 times bigger bang***. So, if Ganymed is solid, we need 39 Tsar Bomba’s to get 2.4 cm/sec velocity change. If Ganymed is a huge rubble pile we need 39 Tsar-Bomba’s to get a 0.8 cm/sec velocity change. 

7: How do we get the really huge bombs out there?
Earth finds out about the impact 16 months prior. We now know from the NASA simulation that how many bombs we need will rest on how fast we can get them out there. There’s zero chance we can reach Ganymed in time using normal missiles – they’re not at all designed for interplanetary flight. Tsar Bomba was a cylinder 2 meters wide, 8 meters tall, and weighing 27 metric tons. Using the most powerful rocket likely to be available in the near future (The American SLS launcher, which is still being developed), how soon can we get bombs out there? I could attempt the maths, but I’m … efficient.


I'm lazy, and the simulator has an ‘intercept mode’ that will tell you how much it mass a given type of heavy lift rocket can get to the asteroid, how many days before impact, and how far in advance we need to launch.

The best I could manage was an intercept 75 days before impact, using an SLS booster, taking 250 days to make the trip – so the bombs need to be launched 325 days before impact, which gives the world about 155 days to ready them. How many bombs do we need? That close, I could only clear Ganymede out of the danger zone by a 35cm/sec push in the VC and in the VN direction – a total velocity change of 49.4 cm /sec. If Ganymed is rubble.... 

49.4 / 0.8 = 61.75. 
61.75 times 39 is 2408. 

So that's 2408 bombs and rockets! 

Even if Ganymed is solid….. 
49.4/ 2.4 = 20.6. 
20.6 times 39 is 802.75 of them! 

Above: The detonation of Tsar Bomba. Imagine the power of hundreds of them.

So the plan is...?
We’ll need at least 800 Tsar Bombas, on 800 SLS (or some equivalent) boosters. 
That's... difficult to do with existing infrastructure levels. I mean, once SLS is up and running NASA might manage four launches a year, at  push, 

Can we up the bang level? Edward Teller proposed a 10 gigaton bomb (10,000,000,000 tons of TNT equivalent). That’s 100 times stronger than the Tsar Bomba. But there’s an upper limit on energy density, even for nuclear fuel, so a 1.3 gigaton device would weigh about 250 tons – and a 10 gigaton one would easily top 1000 tons. We’d still need several, maybe dozens of them. 

Now, as I said above: Someone who calculates rocket trajectories for a living might well know tricks I don't, do some better maths, and be able to cut those numbers by a half, by three quarters even.

That still means we need hundreds of the biggest bombs ever designed. 

Could we get thousands of tons of bomb out there in time? Not in the real, present day, world. But, in the world the story is set in, I have some suggestions for a work around:

  • A 5km body would be plenty devastating if it hit, and only weigh 125 times more than the 1km wide impactor in the simulation 'Defending Planet Earth: Near-Earth-Object Surveys and Hazard Mitigation Strategies'.

  • In the story the world has just undergone a period of tension and arms race. It is  that much more powerful launchers have been developed, to field incredibly powerful bombs like these – that might tie in with the Mars mission happening in the story.

  • There are designs for huge space launchers: The Orion drive we mentioned earlier, a system propelled by throwing small nukes out the back and setting them off, could have easily lifted 5000 tons. That’s plenty of room for a super nuke, and Orion could get it out there incredibly fast as well – it’s so powerful the kind of orbital mechanics the simulation employed here could be ignored. Another really huge (though not so huge as Orion) launcher is in the works: SpaceX's Big F***ing Rocket. Yes that's it's real name. It's launch capacity hasn't been released yet, so we can't do any calculations for it, but is likely to be 2-3 times that of SLS - and the engines are already being tested by SpaceX.
In the end the author came up with their own (frankly brilliant) plot workaround. I really do enjoy helping writers by setting up and solving problems like this. 
Although I stll have to wait for the book to come out to discover whether humanity gets saved.

* Just to be clear Don't try to save mankind with these figures - they were just to give the guy something ballpark realistic to work with!
**Aside from ‘we all scream and die’? 
** Why assume that? Well, a nuke in space as no shockwave, it’s just a huge flash of radiation. We still need to not shatter the asteroid, so we need to change the distance of the detonation to keep the radiant energy per square meter at the asteroids surface the same. That’s easy enough: Radiant intensity changes with the square of the distance to source, so now we have a bomb 1000 times stronger we need to increase the standoff distance by the square root of 1000, or roughly 31.6 times. The original distance was 150 meters. 0.150 times root 1000 equals about 4.75. So 4.75 km is our new standoff distance. Our distance from surface to source has increased by (root1000), so the surface area that is exposed to any given flux of radiation (ie, enough to vaporise rock and produce propulsion) has increased by (root1000) * (root1000) = 1000. So we have roughly 1000 times the surface area receiving the same radiant intensity as we had for the 100kt bomb calculations, and hence 1000 times the vaporising material and 1000 times the thrust. There’s the question of ‘does more of the bombs radiation miss the asteroid at the new standoff distance?’ 4.75km divided by 34km = 0.14. 0.15km divided by 1km = 0.15, so the proportional distance from bomb to target, an hence the proportional amount of radiation lost, is about the same.

Documents used (linked directly to in the text):

[1] National Research Council. Defending Planet Earth: Near-Earth-Object Surveys and Hazard Mitigation Strategies. Washington, DC: The National Academies Press, 2010. doi:10.17226/12842.Chapter: 5 Mitigation

[2] Page 32, Dwarf Planets and Asteroids: Minor Bodies of the Solar System, By Thomas Wm Hamilton

[3] Nuclear overkill: The quest for the 10 gigaton bomb 5 January 2016 Rakesh Krishnan Simha

[4] Nuclear Weapon Archive, B41 Bomb.