Travel time from Moon to Earth... via Mass Driver

Fri, 2012-03-02 17:20

#2

Arenamontanus Arenamontanus's picture

Re: Travel time from Moon to Earth... via Mass Driver

BlackJaw wrote:
My player will be taking a trip to Earth in a mass driver shot, then blowing the semi-hollowed asteroid into sections and emerging in Highdive suits to make their way to the surface. Question: How many days, hours, or minutes will this trip take?

Ah, travelling economy has never been more exciting. Lunar escape velocity is 2.4 km/s, so the initial velocity will be a bit higher. However, the time could be arbitrarily long if you give it *just* enough speed to get through one of the Lagrange points... So the real answer is "it depends". One way of approximating this is to recall that Apollo took three days to coast from Earth to Luna. That is probably a good upper bound. If the Luna mass driver fires it so it leaves near Luna orbit at around 10 km/s, it would take about 8 hours to hit.

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Fri, 2012-03-02 17:56

#3

OneTrikPony OneTrikPony's picture

Re: Travel time from Moon to Earth... via Mass Driver

[Edit] Damnit! A-mont beat me AND did the calculus. Touche' :D [/Edit] You mean like a bombardment mass driver or a shipping mass driver? A bombardment mass driver is going to throw that rock so hard anything probably won't survive. A shipping mass driver will only get you to Low Earth Orbit at best. The distance will be about 386000 Km. You'll need a minimum Delta V of 2.5 km/sec to get to Low Earth orbit, but bombardment mass drivers are probably more like 10 km/sec. Simple division, (that doesn't account for earth's gravity well) will get you there in either 45 hours, or 11 hours if you don't mind dropping rock encapsulated corpses.

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Fri, 2012-03-02 19:09

#4

BlackJaw

Re: Travel time from Moon to Earth... via Mass Driver

How many Gs is that kind of acceleration? My understanding is that a biomorph could survive a shocking number of Gs if you suspend the body in a fluid of similar density to human tissue, including filling the lungs, throat, etc. I'm guessing most of my group would be happy to just use synths, but I'd like to open up the option of having biomorphs.

Fri, 2012-03-02 20:13

#5

Arenamontanus Arenamontanus's picture

Re: Travel time from Moon to Earth... via Mass Driver

BlackJaw wrote:
How many Gs is that kind of acceleration?

Depends on how long the mass driver is. If it is X km long and produces a velocity of V km/s, then the acceleration is 100 V^2/(2X) G (use V=AT, X=0.5AT^2 and that a km is 1000m and 1G is almost 10 m/s^2). For V=10 km/s and X=10 km you get an acceleration of 500G. Doesn't sound that comfortable. A longer driver with X=100 km is just 50 G, which I suspect a solidly packed morph ought to handle well. It is just 20 seconds of acceleration, after all...

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Fri, 2012-03-02 21:38

#6

Decivre

Re: Travel time from Moon to Earth... via Mass Driver

Arenamontanus wrote:
A longer driver with X=100 km is just 50 G, which I suspect a solidly packed morph ought to handle well. It is just 20 seconds of acceleration, after all...

Worst case scenario, you black out for a few minutes. You only need to be awake for shortly before atmospheric impact anyways. An automated medical injection intended to forcibly wake you would do the trick.

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Fri, 2012-03-02 23:36

#7

NewAgeOfPower NewAgeOfPower's picture

Re: Travel time from Moon to Earth... via Mass Driver

Arenamontanus wrote:
BlackJaw wrote:
How many Gs is that kind of acceleration?
Depends on how long the mass driver is. If it is X km long and produces a velocity of V km/s, then the acceleration is 100 V^2/(2X) G (use V=AT, X=0.5AT^2 and that a km is 1000m and 1G is almost 10 m/s^2). For V=10 km/s and X=10 km you get an acceleration of 500G. Doesn't sound that comfortable. A longer driver with X=100 km is just 50 G, which I suspect a solidly packed morph ought to handle well. It is just 20 seconds of acceleration, after all...

A synth would be fine, probably past ~100gs, no need for sedatives... I have extreme doubts about a flat or even a splicer surviving 50gs unharmed... They might be 'alive' but would probably suffer dropped lungs/diaphragms, damaged internal organs, etc. Bomb test shock patches are usually set to 50 gs/ 100gs, as 50gs causes severe trauma, and 100g is usually an instant kill...

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Sat, 2012-03-03 00:19

#8

OneTrikPony OneTrikPony's picture

Re: Travel time from Moon to Earth... via Mass Driver

Here's the relevant data: http://www.projectrho.com/rocket/mission.php#id--Effects_of_Acceleration... 50 G's (transverse) is pushing the bounds of serious injury to biomorphs, especially to the eyes (retinal detatchment), lungs and brain stem, assuming a really good acceleration couch. I remember reading Joel Haldeman talking about the packed in high pressure fluid scheme in his novel "forever war" for maneuvers at 50 G and above but even then people were rupturing internally. EP solves this for biomorphs with the High G Adaptation bioware. I'm skeptical that synths endure high G maneuver any better than tough biomorphs with DUR 40+. All characters resist the same damage from falling or kinetic attacks. [edit] Is anyone else skeptical about 100km long 10km/s mass drivers on Luna? For one thing; there's not much need to accelerate any thing to 10km/s because 1.6km/s will get you into orbit and 2.5km will get you anywhere else in the L-LA system. In the second place; there's not much need to lift anything that is G-force sensitive via mass driver when much of your manufacturing is on site nano-fab. It would be handy, and desirable in the Lunar hydrogen economy, to soft-launch shuttles but that is easily accomplished using the Lunar skyhook track that already exists.

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Sat, 2012-03-03 04:53

#9

Arenamontanus Arenamontanus's picture

Re: Travel time from Moon to Earth... via Mass Driver

http://www.bordeninstitute.army.mil/published_volumes/harshEnv2/HE2ch33.pdf also has plenty of information. Yes, 50 G is not going to be nice to squishy biomorphs. My solution would be an injection of stabilizing nanomachines. I imagine it weaving a web of strong nanofibres throughout the body, keeping everything in place. Sure, you cannot move or function well when it is in place, but it also keeps you from rupturing. For the duration it maintains life functions at a low level, then dissolves the fibres and restarts things. Might work extra well on a hibernoid. 100 km drivers? Yes, there might not be a big market for very fast launches. But if mass drivers are used to do cheap passenger launches to lunar orbit then there is a reason to make them long: passengers are not going to be acceleration-resistant. A 10 km driver will give you 31 G to reach lunar escape velocity. If we say the limit is 10 G, then the driver has to be at least 30 km. So it is not too implausible that the driver is fairly long if it has to gently launch some cargo. And if it is throwing rocks at Earth it still makes sense to make it long, since the lower accelerations mean the material strains get easier to handle.

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Sun, 2012-03-04 02:40

#10

OneTrikPony OneTrikPony's picture

Re: Travel time from Moon to Earth... via Mass Driver

so you don't think that they can just ramp up the current a bit on the ramps and spurs they already use for the skyhook track to soft launch things into orbit? Seems to me that the long, straight track and all of it's associated sidings should be able to be multi-purposed for more than just carrying the skyhook and associated cargo. I guess, even in that case, you'd want some big systems to soft-launch stuff into polar orbits. LOL! I like the nano-web idea but the first visual that came to me was a vivisection ala' a Tom&Jerry cartoon. :D

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Mon, 2012-03-05 19:20

#11

BlackJaw

Re: Travel time from Moon to Earth... via Mass Driver

I'm explicitly talking about automated Weapons of Mass Destruction built during The Fall and still in operation. They are mentioned in the Earth sections of Sunward, although I think they are missing in the Luna sections. Asking if they are cost effective or if there is a market for them is somewhat off topic. That the existing cargo launchers might be retooled for this use is also a bit off topic. The weapons aren't given many details. I'm not clear if they are on the moon or in orbit near it. It's also implied that capture asteroids to fling them, which is different than digging them out of the moon to launch. Honestly, I think the idea of a weapon mounted on the moon so it can only be fired towards the earth, and where it can dig up it's own ammo as needed, makes more sense... but it's also then an instillation that TITANs could have shot back at with some ease. Another idea might be some kind of combo: Diggers on the moon produce ammo, while orbital launchers can move about... although this might be over thinking it.

Mon, 2012-03-05 23:10

#12

OneTrikPony OneTrikPony's picture

Re: Travel time from Moon to Earth... via Mass Driver

Sorry BlackJaw, I didn't mean to derail, (haha pun!) your thread. IIRC the bombardment of earth with rocks launched by mass drivers on the moon is a current event circa AF10. You're right those "guns" exist. It's just my opinion that they accelerate too hard to be of any utility to would-be stowaways. So, I was thinking about cargo launchers that don't hit so hard. You're also correct that these mass drivers are on the surface of Luna. There is a specific mention of a smaller settlement, either Fenyman or Clever Hands, that has their own mass driver. It's just my opinion, but mass drivers in orbit around Luna are probably not cannon and also probably not a good idea; newtonian physics and all that. I'm not saying they couldn't exist just that I've never read about them and I can't think of any reason for them. Like Arenamontanus said; the transit time would be about 8 hours, in that case. I hope I was more than less helpfull in this post. :)

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Mea Culpa: My mode of speech can make others feel uninvited to argue or participate. This is the EXACT opposite of what I intend when I post.

Tue, 2012-03-06 13:22

#13

BlackJaw

Re: Travel time from Moon to Earth... via Mass Driver

Sorry, I didn't mean to get insulting or angry. Everyone is being very helpful. The reason to use the weapon-grade mass launchers instead of some other method (including reconfigured cargo launchers) is that the cordon around Earth expressly allows the weapon attacks through, while everything else tends to get shot to hell. As a GM, I'm actually digging the idea that the players will all take a massive crushing attacking at launch and have only 8 hours to repair/heal from it before having to deal with a bail-out in re-entry using High Dive Suits. The next question, I guess, is what kind of damage will this acceleration deal to them? It would obviously ignore armor, and will inflict wounds, possibly killing them (which isn't a permanent effect in Eclipse Phase, so it's not a big concern.) What kind of numbers should I be looking at. Should I allow some kind of Som check to reduce the damage? Alternative idea: The players don't start on the rock. They meet it in transit and hop on board as it goes by. In this scenario, they use an anti-matter fast courier to accelerate up to the rock's speed (or close to it as it passes by), thus allowing them to sort of meet the acceleration without having to do it so quickly it kills them all.

Tue, 2012-03-06 17:10

#14

Madwand

Re: Travel time from Moon to Earth... via Mass Driver

The "meet in transit" idea probably won't work for a weaponized mass driver shot, because the delta-v would probably be too high even for a courier, and the rendezvous would be detected (there is no stealth in space) and the rock targeted by the automatic defenses. Any weaponized mass driver would probably inflict so much damage to a biomorph on lauch it would be utterly destroyed; nothing left but very flat jelly. A specially designed synth has a chance. A few cortical stacks surrounded by specially packed feedstock and protean swarms could survive launch; the protean swarms could then construct a synth body around the stack on the trip. Note that the mass driver shots probably aren't very large; both because the people firing them don't want to waste energy; and a few hundred kilos of rock is probably more than enough to destroy a small city at those speeds. You might be able to fit *one* specially-packed cranial stack+feedstock per shot, so you are going to need one shot for each member of the party you are going to send. This brings us to our last and largest problem; decelleration. Frankly, I can imagine nothing the PCs can do will save them upon arriving at their destination; they simply can't pack enough energy to decellerate enough to not be vaporized. tl;dr: This won't work via weaponized mass driver shot. It could work via a cargo launch shot; but that carries it's own list of problems. Decelleration at the end is still a problem. Your PCs best bet is a spaceship.

Tue, 2012-03-06 18:27

#15

Decivre

Re: Travel time from Moon to Earth... via Mass Driver

BlackJaw wrote:
Alternative idea: The players don't start on the rock. They meet it in transit and hop on board as it goes by. In this scenario, they use an anti-matter fast courier to accelerate up to the rock's speed (or close to it as it passes by), thus allowing them to sort of meet the acceleration without having to do it so quickly it kills them all.

Probably the best option. People looking to get to Earth probably free-fall at slightly faster trajectory to meet up with the projectile from a ship. With a decent amount of training, this would take minimal effort, and a 7-minute window (assuming they meet the projectile a minute into flight) is plenty of time to prepare for landing. The other option is slinging the projectile; using a craft to tow the projectile towards the Earth, then releasing it to let it do damage. This process would be cheaper than the production of mass drivers, easier to pull off, and exponentially safer for stowaways wishing to cling to that projectile. Sure, the speed of the projectile will be miniscule in comparison... but it's the mass that does the real damage anyways.

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Tue, 2012-03-06 18:26

#16

BlackJaw

Re: Travel time from Moon to Earth... via Mass Driver

Madwand: So what you're saying is that the whole cool idea spelled out in Sunward in multiple places is impossible. Somehow, I don't buy that. The Berringer Crater was made by a 50 meter nickel-iron meteorite traveling at 12km per second. Apollo 10 has the speed record for a maned vehicle at just over 11km per second (11,107 meters a second) The Stardust sample-return capsule was the fastest man-made object ever to reenter Earth's atmosphere (12.4 km/s) I think the plan sounds fairly possible to me given Eclipse Phase level technology. A ship beings accelerating past the moon more or less headed towards Earth. As it passes the moon, the lunar mass driver fires, launching a rock at around 12 km/s. The ship and the rock end up on gently crossing paths, allowing the crew to transfer onto the rock without their direction changing more than a fraction of a degree. The ship is traveling towards earth, and is made with stealth materials. It's engines are firing, but they are firing away from earth so it's not visible. It's a black speck noticeable only as stars being blotted out behind it. As stealth as ships get in space, and hard to spot given the amount of debris floating around Earth in Eclipse Phase, let alone standard orbital and lunar activities & ships.

Tue, 2012-03-06 18:40

#17

Madwand

Re: Travel time from Moon to Earth... via Mass Driver

What actually matters when doing damage is energy, which goes up with the square of velocity, but only linearly with mass. Your best bet for long-range bombardment is going to be a high-speed, low-mass mass driver launch. A spaceship is a very inefficient platform when using it's engines to accelerate a mass driver launch, unless the spaceship itself is the projectile. This is because the ship not only requires the extra energy to move itself AND the projectile, it also has to decellerate, accelerate on the return voyage, then decellerate again to get back to it's starting point. Assuming the mass of the projectile is the same as that of the ship, that's five times the energy needed to simply fire a mass driver. This is ignoring many other innefficiencies of using a spaceship. Finally... if you WERE to use a spaceship to do this, it would be very, very obvious. High-energy uses of space engines are very, very visible. Your target would know the rock is incoming, and many details about the ship that launched it, well in advance of the rocks arrival. This is a good way to get shot down. Read this for further details: http://www.projectrho.com/rocket/spacewardetect.php#nostealth Oh, yes... and I'm suggesting that a weaponized mass driver fires MUCH faster than 12 km/sec.

Tue, 2012-03-06 19:35

#18

BlackJaw

Re: Travel time from Moon to Earth... via Mass Driver

Ah, so you're talking about smaller, faster, projectiles... which would be too fast to catch up with, too fast to safely get off from before impact, and too small to ride on anyway. Yes: That ruins the whole idea. Which is why I'm going with bigger, slower ones so I can use the cool idea laid out in Sunward, even if it isn't how things would likely be done. I here by fully acknowledge that this is getting out of reasonable and into unreasonable in order to justify a cool mission. Moving on: The idea I had wasn't to use the ship to accelerate the mass driver shot, but to meet up with it in flight. The shot is still being fired by one of the automated anti-TITAN mass drivers on Luna. The stealth thing: Well I guess they see it coming... which could be interesting. I had hopped the dark bodied spacecraft antics seen in Singularity Sky, a novel by Charles Stross, were close enough to reality to be viable here, but your link seems to indicate that heat radiation would be too much of an issue. I'll just have to wave the PLOT wand and declare the killsat cordon to be hard coded to allow the mass driver shots through. All this allows me to: 1) Have the players make a cool piloting check/navigation check to meet up with the mass driver shot in transit. 2) Make a freefall check to transfer themselves and their gear to it. 3) Attempt to survive re-entry in a High Dive suit while a mass driver impact goes off under them. Sounds like a fun opening to a mission to me.

Tue, 2012-03-06 19:42

#19

Arenamontanus Arenamontanus's picture

Re: Travel time from Moon to Earth... via Mass Driver

BlackJaw wrote:
Alternative idea: The players don't start on the rock. They meet it in transit and hop on board as it goes by. In this scenario, they use an anti-matter fast courier to accelerate up to the rock's speed (or close to it as it passes by), thus allowing them to sort of meet the acceleration without having to do it so quickly it kills them all.

I like it. The rock velocity is likely well within even fairly normal spacecraft delta-v levels (if it is around 12 km/s), and if it is weapons-grade around 100 km/s the courier can still catch up with it. Visibility will be obvious, but this is where spin doctoring can make all the difference: "And in today's most expensive and pointless stunt, interplanetary playboy Jin Hinakura caught up with Mass Load 4335 to paint graffiti on it. He caught up with it using a chartered courier, wrote 'Look out, Titan fuckers!', and left before it plunged down on Earth. His ex-wife Cindy DeLamara commented that he should have stayed on the load." Damage for being on an accelerated cargo: 50 G is likely survivable, https://en.wikipedia.org/wiki/John_Stapp#Works_on_effects_of_deceleration but beyond that the forces start getting nasty. Consider that the weight of the 300 gram human heart will exert 150 N of force at 50 G, distributed across perhaps 30 square centimetres. That will be 50 times normal arterial blood overpressure - it will not be beating properly, if at all. I think just handing out a lot of Wound levels is the proper approach...

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Tue, 2012-03-06 19:50

#20

CodeBreaker CodeBreaker's picture

Re: Travel time from Moon to Earth... via Mass Driver

BlackJaw wrote:
Yes: That ruins the whole idea. Which is why I'm going with bigger, slower ones so I can use the cool idea laid out in Sunward, even if it isn't how things would likely be done. I here by fully acknowledge that this is getting out of reasonable and into unreasonable in order to justify a cool mission. .

Pfft. While I think we should try and keep our science hard, I am a firm believer in the Rule of Cool. If something is fun, isn't too wacky, and triggers an imaginative scene, include it. The setting is already filled with RoC stuff. I don't think having players cowboying a rock down the gravity well will be the straw that breaks the camels back

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Tue, 2012-03-06 20:27

#21

Decivre

Re: Travel time from Moon to Earth... via Mass Driver

Madwand wrote:
What actually matters when doing damage is energy, which goes up with the square of velocity, but only linearly with mass. Your best bet for long-range bombardment is going to be a high-speed, low-mass mass driver launch.

You forget to take into account gravity. A high mass slow projectile will accelerate as it approaches Earth simply by merit of this. On the converse, a low mass fast projectile will accelerate very little. Plus, there is the obvious advantage of being able to stow away on the larger projectile safely. You are forgetting that little bonus.

Madwand wrote:
A spaceship is a very inefficient platform when using it's engines to accelerate a mass driver launch, unless the spaceship itself is the projectile. This is because the ship not only requires the extra energy to move itself AND the projectile, it also has to decellerate, accelerate on the return voyage, then decellerate again to get back to it's starting point. Assuming the mass of the projectile is the same as that of the ship, that's five times the energy needed to simply fire a mass driver. This is ignoring many other innefficiencies of using a spaceship.

You are assuming it needs to return the way it came. A ship used for this sort of mission, perhaps coming from the belt and heading toward Venus, could easily tow said asteroid along the way, untether it once the ship reaches a distance where impact is assured, then continue on its voyage with little course correction so long as everything is planned out appropriately. A towing ship does not need to solely tow... in fact, this could be a handy side-job for a courier working for Firewall before it goes back to its normal routine.

Madwand wrote:
Finally... if you WERE to use a spaceship to do this, it would be very, very obvious. High-energy uses of space engines are very, very visible. Your target would know the rock is incoming, and many details about the ship that launched it, well in advance of the rocks arrival. This is a good way to get shot down. Read this for further details: http://www.projectrho.com/rocket/spacewardetect.php#nostealth Oh, yes... and I'm suggesting that a weaponized mass driver fires MUCH faster than 12 km/sec.

The issue isn't obviousness. Firing a mass driver is already blatantly obvious. In fact, you can't get much more obvious than firing a mass driver. The orbital defense grid doesn't seem all that pre-occupied with bombardment... otherwise, it would have assaulted the Moon quite a while ago. So subtlety of the attack isn't the necessity. What is necessary if sneaking back to Earth is hiding the presence of stowaways, a process far easier with a larger projectile (especially one from the belt, where you might find it pocked and hollow) than a smaller one.

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Tue, 2012-03-06 23:05

#22

OneTrikPony OneTrikPony's picture

Re: Travel time from Moon to Earth... via Mass Driver

Some quick thoughts: 1. The interdiction cordon around earth does allow bombardment masses through without attacking them. you can find that in sunward. 2. It is already cannon that one scheme for dropping in on earth is riding one of these masses down. you can find that in sunward (I'm 90% certain of this although there are caveats concerning the intelligence of this method in that same text) 3. In the EP universe there *Can Be* stealth in space, despite what science tells us and the limits of any imagination based on science (so far). This is established by the rules in Panopticon. While I don't personally agree with some of this stuff, and it will cause tech-savy players to go 'whafuc?' a GM is kind of limited by what the books allready tell players they can do without application of nerfing houserules. Blackjack; I say you're good to go with your adventure as written. If it were me, I'd decide how much G for velocity I wanted the launchers to produce then I'd sketch out the math to see if they look like something I think would exist to decide if the stowaway option is viable in my game. To decide how much G I wanted the driver to produce I'd look at the character's resources and decide how much work they need to do to survive it. It's a great way to decide how much of their resources you're going to take away from them. Same thing with meeting the rock in transit. Look at Panopticon and use the sensor and stealth rules to decide if it's viable then decide how much it will cost your characters to charter a courier and if they might have to egocast some where else to actually meet it. (by my scratch, it will take a courier ship with a thrust of .2G 16 hours to make 12km/s so they may need to embark from the L2 point or take some coincidental orbit that will allow them to run up to speed) Perhaps they can use the Lunar Cyclers somehow. My 4th point is; By cannon you're not doing anything that is entirely implausible or breaks the setting. You just need to decide how hard and expensive you want this to be for your players depending on how well adjusted they are to the tech and the setting and the resources their characters can access. I've been playing a reclaimer for over a year now we have yet to take a crack at getting to the surface so I'm highly interested in how you set up your adventure and how it works out. Please keep us posted.

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Mea Culpa: My mode of speech can make others feel uninvited to argue or participate. This is the EXACT opposite of what I intend when I post.

Wed, 2012-03-21 01:16

#23

Pyrite

Re: Travel time from Moon to Earth... via Mass Driver

From an earlier comment I feel the need to point out that while death is not that big a deal in Eclipse Phase, a real risk of death at the first stage of the mission like this leads to the chance of someone showing up to make a single roll and then they may as well go home. You've got to pitch them softballs at the session opener. Unless the actual ride is the culmination of the previous session, all centered around making this crazy scheme actually happen. But then you risk your players coming up with something more practical and less crazy.

—

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Wed, 2012-03-21 03:15

#24

BlackJaw

Re: Travel time from Moon to Earth... via Mass Driver

I actually ran this already. It was part of the finale of an arc I was running. Before I describe how it went down, I'd like to thank everyone that responded with advice, math, and constructive criticism. The players seemed to think that it was an impressive stun that also helped spell out just how much of a hail Mary mission they were being sent on. Here's how it went down: This is the 9th & final mission in a story arc, but at this point the players need to get to Earth and locate a beacon (that they aren't even sure still works.) The cordon around Earth scrambles the radio signals from the beacon, so they are having to make their best guess about where to go. Worse, they need to get there so ASAP, for the fate of Trans-humanity is hanging in the balance. Normally if Firewall was going to risk a trip to Earth, they'd spend months mapping & plotting the kill-sat coverage over the target area, then fire off a spread of automated probes to land and setup shop, then Farcast via Neutrino beam down to which ever probe made it's way to the surface. It's works (the Reclaimers do it) but it takes time, and the players don't have that kind of time. They have days, maybe a week, not months. It's time for a long shot; literally. Their friendly Firewall Vector (Proxy level hacker) has control of one of the lunar mass drivers. The weapon has a wide range of capabilities, from firing small rocks very fast to firing big rocks at "slower" speeds. It's all part of the system's ability to put the right size explosion in the right place at the right time. Considering the distances traveled between the Earth & Moon, and the orbits and rotation of each, this flexibility sounded at least reasonable at the time. The Vector sets the weapon to fire a good sized (50 meter) rock at a speed of 12km/second to land near (not on) Mumbai, which is the player's target destination. The weapon is set to fire at a known time, so the flight of the asteroid is all calculated out in advance. These settings were defined by the Vector for his purposes, not as standard system settings. Still, the mass driver acceleration is still too fast for morphs and their gear to get through safely. So... the players have got their hands on a courier ship (Firewall regularly does this kind of thing for them when it's justified, renting a ship under assumed names, etc.) , which they whip around Luna as they accelerate up to just about 12km/second. They do this using the weapon's firing solution and some teamwork on the navigation and piloting checks. These are skills they are good at, and as I bet, they didn't screw up. They succeeded with something like a double Excellent, and had an easy time making the Free Fall (or piloting, depending on systems) check to get their morphs onto the rock because of it. The (now reported stollen) ship, on autopilot, decelerates as it curves around Earth, and eventually returns to the general Earth/Lunar area it started in. Somewhere a Firewall cover ID drops lots of credits into a numbered Extropian Bank Account. For bodies most of the team used Steel Morphs (modded for combat) wearing High Dive suits. One player opted for his favored robot-spider body, and he had previously succeed on a difficult time limited engineering check to get a High Dive suit set of upgrades onto it. He did have a steel morph on back-up in case he failed, of course. They were all also carrying about a backpack worth of gear & weapons (worn on their chest as part of the High Dive suit, which they swapped to their back once they landed) including armor mod applicators and stealth cloaks... stuff that would probably burn off their high-dive suits if applied before landing. The suits effectively limited just how much gear they could bring with them on this perilous mission. As cover for the ship connecting passing the mass-drive-rock, one of the players was sleeved in a Worker Pod with emergency far-caster, also in a high dive suit. Her character concept from way back is actually a (crazy) suicide artist whose (illegal) XP recordings of unique and creative deaths are her main income. Most of the team avoided her on the ride to Earth, but she also had visual editing software running on her cyberbrain so she couldn't see or interact with them on the trip anyway. Her host of creativity/acting skills and Async powers helped as well. Her fork got some stunning (gruesome) XP of riding a mass driver shot to Earth (to sell on the black market) and the public in general would have an excuse for why a (stolen) shuttle interacted with a mass driver shot. I offered the player a steel morph to complete the mission with the team as well, but she sadly couldn't stay that long. As the mass-driver-shot reached the Earth Cordon, the players got very tense. Firewall had told them that the Kill-Sats might not like the setup. The players made infiltration checks and used stealth gear while the kill-sats moved out of the way, but kept their sensors and weapons trained on the rock. I made a couple of dice checks, half to freak them out, but I was willing to back it up with a few pot-shots from the kill-sats (I'd argue, for game-fun purposes, that the kill-sats programming wouldn't let it blow up the white-listed mass driver shot, but it could try to shoot the tag-alongs with smaller weapons). It didn't come to that, thanks to the players trying not to stand out, and the kill-sats pulling back. As GM, I got the tension I wanted and decided not to push it. When the rock hit the upper atmosphere, the players (other than the suicide artist) bailed out and made use of their High Dive suits. This worked well, until the mass driver shot hit the ground and sent out a massive explosion. The players with good Free Fall skill checks did fine, and the rest used Skill Wires. One player got blown off course and slammed into the ruins of a high-rise office building in Mumbai, taking some damage and loosing some gear. He then had to infiltrate his way through a TITAN destroyed city to meet up at the intended landing site. (I used the impact blast from the not too far off mass driver impact as a reason for why most of the flying drones and nanite clouds weren't in full swing yet, and also to help them with being hard to spot in general. From there they made their way to their way towards a locator beacon and the rest of the mission (which is off topic, but involves being swallowed by a destroyer... which tends to cause mental stress.)