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I'm writing a soft scifi novel that has its fair share "fi" but every now and then I feel it important to acknowledge some "sci."

In this scenario, a spaceship is in orbit and about to land on Earth. It's also in communication with Earth, and under observation. But some characters want to "abandon ship" and land on Earth undetected -- or at least have a head start before they're detected.

I'd prefer not to use "cloaking" as an answer (though I'm not above that if it's the only option haha!). I was thinking they could board an escape pod and just "Indiana Jones" their way to Earth. But is this at all plausible in context of existing technology?

Edit: I was unclear about the nature of this spaceship. It's not alien tech; just super cutting edge (a cut above realistic, basically). There's wiggle room in its capabilities, but I'd like to keep it as believable as possible.

Another note: I decided not to choose a winning answer! All of these answers and comments are so helpful, I won't chose any as the best. But thanks to all of you for contributing!

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    $\begingroup$ Are these pods built in features to the Space Ship? Also and I want to be really sure about this, the Ship is a reasonably modern day human built space craft and not relying on super science or alien tech in anyway? $\endgroup$ – hszmv Jun 11 at 18:15
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    $\begingroup$ How big is the pod, and what counts as "detected" ? We don't see small asteroids until they light up in the atmosphere; if your pod can "glide" and soft-land, and add in some stealth-radar coatings, it wouldn't be too hard to land in some remote location. $\endgroup$ – Carl Witthoft Jun 11 at 18:16
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    $\begingroup$ One meter wide? Sure. Two meters? Most likely. Ten meters? Maybe. Fifty meters? No way. On the other hand, if it comes ballistic from deep space it may well be mistaken for a meteoroid. $\endgroup$ – AlexP Jun 11 at 18:18
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    $\begingroup$ So far, you've said that this is an "escape pod," not a purpose build "sneak pod." There will be no stealth features built in because the builders want it to be seen. The pods purpose is to be "step 1 of being rescued." $\endgroup$ – ShadoCat Jun 11 at 19:39
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    $\begingroup$ The odds are not quite zero of your team being mistaken for a nuclear first strike and triggering nuclear war. $\endgroup$ – Emilio M Bumachar Jun 12 at 17:03

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If I remember my sci-fi correctly, I think one of the more accepted methods of doing this is using the 'hide a tree in a forest method'. In other words, just hide the escape pod within a meteor shower, and use atypical methods, such as deploying the equivalent of a BASE parachute at the last possible moment, or something of that nature.

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    $\begingroup$ I like this idea. Especially if the ones who want to leave the ship is some kind of rouge faction. The bulk of the crew is occupied with securing the craft preparing for the meteor shower, so the faction can sneak away to the escape pod and hide in the shower on the way down. They may be gone undetected from both sides for quite a while. A daring escape! $\endgroup$ – Bex Jun 12 at 7:06
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    $\begingroup$ A meteor shower will cover your re-entry from a visual standpoint, but you've still got radar to deal with. A re-entering escape pod looks nothing like a meteor on radar, but it does look rather a lot like a re-entering ballistic missile. $\endgroup$ – Mark Jun 12 at 21:55
  • $\begingroup$ Depends on the profile on the pod, really. A normal pod, no. On the flip side, if you custom build the pod for the purpose... $\endgroup$ – Halfthawed Jun 12 at 21:57
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    $\begingroup$ If you come in over land, scientists will detect this "meteor" and will scout around where it would have landed. Meteorites are worth a lot of money. But if you come in over the ocean, no one will bother looking for it. Their listening stations will detect the sonic booms, but beyond that no one will care much. $\endgroup$ – Ryan_L Jun 12 at 23:33
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    $\begingroup$ "If they follow standard Imperial procedure they'll dump their garbage before they go to lightspeed." $\endgroup$ – AndreKR Jun 13 at 7:26
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Putting aside whether the "escape pod" has enough delta-V to break orbit, depending where they reenter it's very possible. I'd put the mother craft in a polar orbit, so they can reenter over the extreme southern Pacific, near the "pole of inaccessibility", and pass over Antarctica during the hottest part of the trip, then land in the extreme southern Atlantic near Elephant Island. With good timing (put the Pacific part during daylight, ideally near local noon), they might be visually seen by as few as several hundred people -- most of whom are in no position to immediately report the "bright meteor" passing near them.

No, not a convenient location, but one might be able to push it as far north as the Falklands (to have a nearby airport), since the last part of the landing isn't very visual -- land in the dark with a no-longer-meteoric spaceship, even large parachutes might go completely unnoticed.

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  • $\begingroup$ Thanks a lot! I edited my question, as I forgot to add that the ship would be under observation from Earth. $\endgroup$ – cal Jun 11 at 18:34
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    $\begingroup$ There are probably some ways to decrease the net brightness. An ablative hull that kept the temperature lower would dump heat at the expense of leaving a lot of stuff in a trail. As well, entering at a time when the sun is in people's eyes. Also, using a pod with very little radar signature will help. Also, some jim-jam to convince people you are still aboard, such as relayed signals or recordings or such. $\endgroup$ – puppetsock Jun 11 at 18:42
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    $\begingroup$ There's poor radar coverage south of Hawaii -- virtually nothing pointed at the sky that could see an orbiting craft. Reenter at noon and virtually no one will see, and over Antarctica, there's virtually no one to see. $\endgroup$ – Zeiss Ikon Jun 11 at 18:47
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    $\begingroup$ You don't need much delta-v to change the orbit sufficiently to reenter the atmosphere. Compare How could a 90 m/s delta-v be enough to commit the space shuttle to landing? on Space Exploration. Full disclosure: My own question. $\endgroup$ – a CVn Jun 12 at 14:51
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    $\begingroup$ To just get down, yes, very little dV is needed (I'm a pretty decent KSP player). To get down in a fairly precise location, and minimize your meteoric footprint, requires more dV and a steeper reentry profile (which also keeps the heat soak from cooking the occupants, though they take more Gs during descent). $\endgroup$ – Zeiss Ikon Jun 12 at 15:42
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  • Is the ship under observation for routine traffic control or other purposes?
    If people on Earth are serious about watching, and if they are already observing the ship, breaking contact will be difficult. Aircraft like the Cobra Ball or Cobra Eye might be deployed to fill gaps in the ground coverage.
    If it is routine, Earth might rely on secondary radar and transponder, and a non-transponding pod has much better chances.
  • Are Earth nations cooperating?
    Large parts of Earth are governed by nations without sophisticated air defenses.
  • Is the capsule stealthy or deliberately visible?
    An emergency escape capsule may be designed with colorful parachutes, automatic and redundant transponders, dye markers in case of water landing, etc.
  • Consider historical lost aircraft cases.
    Steve Fossett got lost in a small aircraft over the United States, a country with quite sophisticated air traffic control. MH370 was even larger, but over the ocean.
    On the other hand, a reentry with aerobraking means a visible trail. North Korean missile tests were visible to civilians in Japan.
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    $\begingroup$ Aerobraking can be done over large bodies of water to reduce the number of witnesses. Lithobraking can also be a very efficient way to shed KE. $\endgroup$ – Aron Jun 12 at 5:04
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    $\begingroup$ @Aron even if your passengers could survive slamming into rock at mach 10 ... and the impact didn't trip seismographic detectors across the country ... you still make quite a light show before you even reach ground. $\endgroup$ – John Dvorak Jun 12 at 11:59
  • $\begingroup$ @JohnDvorak I was actually thinking more like slamming into the ocean and creating a massive tsunami. $\endgroup$ – Aron Jun 12 at 15:37
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    $\begingroup$ @Aron water is surprisingly unyielding at any appreciable speed. At mach 10, water and rock are the same thing. In old KSP, collision with water behaves the same as collision with ground, except it left no debris. And that's pretty much what happens in real life, too. $\endgroup$ – John Dvorak Jun 12 at 15:40
  • $\begingroup$ A significant difference between OP's scenario and Fosset & MH370 is that Five Eyes, the Chinese, Europeans, Japanese, etc (and just about every astronomer om the planet) will all be watching this space ship about as intently as possible. $\endgroup$ – RonJohn Jun 12 at 18:05
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It's going to be very difficult to remain undetected. In fact, it's possible to see the dragon space capsule, which a reasonable size for the escape capsule, with naked eyes alone. Amateur satellite trackers could very well see the separation or the fact that there are two objects where there is supposed to be one and report it on twitter. Military/traffic control space surveillance systems radars could also detect that there are two objects when there is supposed to be one and immediately call up the people aboard said spacecraft to ask them what's going on. A super cutting edge spacecraft or one with people on it is likely to be a prime target for space surveillance. Space surveillance is likely to become more important as space technology advances.

However, the US's current space surveillance network does not have extensive coverage though, there is minimal coverage in the southern hemisphere. A hand wave for detection by large government space surveillance radars is that they may not wish to reveal how good their radar systems are, so they may delay reporting of the separation. A bigger problem is keeping the escape pod separation secret from those onboard. This will create lots of sound and change the mass of spacecraft. The change in mass will be immediately apparent as soon as the spacecraft maneuvers.

There are other ways for the characters to abandon ship discreetly even if the escape pod is detected. One is to make an unscheduled delivery to earth. We may have some refrigerator fail necessitating an experiment or extremely valuable medicine to be returned to earth before it gets too hot. One of the spacecraft's engine's could have an 'accident' meaning the escape pod has to be ejected so that the spacecraft can safely land. The spacecraft may dispose of some garbage before landing using a now unnecessary escape pod.

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In addition to the fact that it will almost certainly be seen in flight there's the fire of re-entry that you can't hope to conceal even if you put stealth systems on it--it's not the capsule that you're seeing, but the plasma it leaves behind. This will be obvious to the naked eye so the only way you can hope to get down unseen is to ensure there are no naked eyes--burn in over Antarctica. Unfortunately, unless your escape pod is also an aircraft (I would expect some glide capability but that's not enough) that means you're going to put down in a very unsafe place (either on the ice or on the seas around it.)

Note that if the craft they are departing from is military in nature (the presence of escape pods suggests this) getting from the ship to atmosphere undetected might very well be possible--such a craft very well might put some stealth features on an escape pod. Combine that with departing during darkness and they should be able to remain hidden until they hit atmosphere.

Your question doesn't make it clear exactly what their objective is, either--are they trying to conceal their existence, or avoid being located? Because in the latter case the answer might very well be to parachute from the pod at 40,000'. The escape pod continues it's journey and suffers a parachute "malfunction", the smashed bits sink to the ocean floor. Meanwhile the people are drifting down under chutes with a good glide ratio and could end up 30 miles from where they jumped. You'll need stealthy gear but that's not that hard--all the main components of a chute are already basically transparent to radar, it's the hardware you need to worry about, as well as the oxygen bottle (they can be made of fiberglass, metal is not essential there) needed for the jump. Doing this will severely limit what they can bring with them, though, due to the need to be stealthy. (The jump altitude is because even pure oxygen is useless above 44,000'--it's suits or die. Once they're below that they have to dump cabin pressure and get out and they'll be falling pretty fast so I'm giving them a few thousand feet to do it in. With a fully automatic system you could jump from a bit higher altitude but I have a hard time imagining why anyone would build such a system and nothing jury-rigged would be stealthy.)

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  • $\begingroup$ Has oxygen-only ever been tested by anyone? The average human's lungs can withstand a 2-3 psi pressure differential and a human in good physical condition needs somewhat less than 2psi partial pressure of oxygen to remain conscious. I'd think nitrogen embolism (bends) or hypothermia from evaporating skin moisture would be the biggest issues, but it might well be possible to overcome them without a full suit with sufficient acclimatization and tolerance for pain... $\endgroup$ – Perkins Jun 13 at 21:56
  • $\begingroup$ @Perkins High altitude jumpers have to pre-breathe even with ordinary military jumps. Hypothermia wouldn't be an issue, easy enough to wrap up enough--I rejected suits for what they're made of, not for being bulky. Where are you getting the lung strength from? $\endgroup$ – Loren Pechtel Jun 14 at 0:13
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    $\begingroup$ I'm not sure how well simple insulation would help with the hypothermia since much of the heat loss would be evaporative cooling. Lung strength studies are commonly discussed on SCUBA forums. The general recommendation is not to risk more than 1.5PSI so as to leave a safety factor because lung health and conditioning make a large difference, but average maximum exhalation pressure of healthy adult men seems to be 2.5 to 2.75 psi if I'm interpreting the numbers correctly. thorax.bmj.com/content/thoraxjnl/47/11/961.full.pdf $\endgroup$ – Perkins Jun 14 at 1:02
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One thing about human space flight in the present day is that Mission Control monitors everything and I do mean that. If you ever watched the film "Apollo 13" you'll recall the scene where Mission Control reports about some minor spike in Jim Lovell's vital signs, which is the straw that breaks Lovell's cabin fever, and he rips of the signal monitors ("I don't need the entire western world to know that my god damn kidneys are functioning"). Space Craft are going to be monitored for all sorts of trouble and anything out of the ordinary will get noticed.

Another Problem is that, an escape pod is typically used as an abandoned ship device... the priorty of which isn't "Where to Land" but "Get away from the space ship". It's likely that the pod is alarmed so that if put into emergency seperation mode, it's going to start sending out "Houston, Problem!" signals to NASA. It's probably also going to start a broadcast Mayday signal which is the International Aviation code for priorty communications to anything watching air plane traffic and clearing runways and landing areas for emergency landings. Despite its airplane like shape, the shuttle orbiter (the plane looking part of the entire stack known as the Space Shuttle) never really flew... to quote one famous space man, the orbiter was more "Falling with Style". An escape pod will likely have batter power and rations to survive in the wilderness for some time, and broadcast a signal to the search teams. This would likely be an unencrypted signal as these emergencies aren't really concerned with which nation finds you, so long as someone does. Shuttle aborts include a number of abort to locations, based on position (Spain and Easter Island are two I recall immediately). As well as water ditch (attempted during The Challenger Disaster, but by the time the crew knew something was wrong, it was too late) and the only abort ever used, Abort to Orbit (essentially they cannot achieve the mission orbit but can enter a lower orbit just fine). The best way to ditch SAR teams would be to have the pod come down in a remote area with very little hope to find people and then hope the team in the pod can ellude SAR operations.

Your best bet is to determine where you want the ditch to be, and then get the team's math nut to calculate the window for pod jettison to make the landing. NASA is going to be aware that something is off (They may not know specifically that it's a secret mission but there will be a lot of noise). This may require the services of someone who knows which wires to cut to disable the alarms and tracking features as well as how to override the landing functions (most orbital landings are computer controlled as again, the Orbitor is falling with style.

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Short answer

Your craft can't even land on Earth, and the defectors explode on re-entry, or they get stuck in space forever and starve to death.

If you suspend reality, the answer you're looking for is:

Merely by initiating an unannounced landing you already have a headstart. I tried like to hell to find astronaut recovery times, but I couldn't track any down; which to me implies that pre-planning reduces the time so low that it's not even worth talking about. Recovery teams have already been positioned near the estimated landing zone to shorten recovery time. For the Apollo 11 mission, the recovery ship was only 7 miles away from splashdown (ctrl+f and type "7 miles"). If you land in a relatively remote region, it would probably take days to find you. If your team was comprised of experienced trackers, they could use their skills to avoid making tracks themselves, and possibly even avoid capture altogether.

EDIT: I just realized days later that I totally forgot to mention, de-orbiting only takes minutes, while it could take hours, even days, to reach your landing spot, depending on the pursuer's method of travel

Long answer

If you are really serious in acknowledging the "sci" of sci-fi, then the real question you need to ask yourself is, can the escape pod even land on Earth in the first place. There some factors that need to be accounted for before you even worry about stealth (in order of appearance):

  • Does the craft have enough fuel to de-orbit? An escape pod using "modern" technology, no matter how cutting-edge it is, would have one purpose, keeping the occupants alive as long as possible so they can be rescued. They would not waste space with engines, fuel storage, flight controls, and navigation. The ejection system might be able to de-orbit the craft, but what if it can't? You are either stuck in high orbit around Earth and will need rescue, or you are stuck in low earth orbit and need rescue, which, while the orbit does decay, it could take years and the occupants would be dead long before then
  • Does the craft have systems to deal with re-entry heat? It's very easy to burn up when entering our atmosphere. Air resistance is not a joke, it will kill you quickly and easily
  • Does the craft have lift surfaces to provide aerodynamic control, ie wings and ailerons? You might get away with having no propulsion, but unless you're really lucky, you will need these to land in a good place and avoid hitting things, which would kill you. Probably not, because "modern" early-tech escape pods would be little more than a pressurized can with a bunch of food in it, and a communications device, or perhaps even just a transponder
  • Can the craft even survive crash landing
  • Are the occupants skilled enough to disable the automatic SOS that is sure to activate immediately after the pod is engaged?

The operation you're describing would require a highly-specialized, purpose-built craft.

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  • $\begingroup$ That would depend on the design of the escape pod. For example, the ISS could use the docked Soyuz capsules as "escape pods" in the event of an emergency, and those are capable of landing. If this is a limited spacefaring setting (so no major interstellar civilization), it's reasonable to assume these "escape pods" are designed for landing as there won't be many other ships around in space to come pick them up. $\endgroup$ – Troyen Jun 12 at 20:58
  • $\begingroup$ I disagree, if the craft was capable of that much, it would not be called an "escape pod". Even if the something happened at the ISS, the astronauts would not say they used an "escape pod". Escape craft only have 2 functions, escaping danger and rescue. If it was capable of anything more it would have a different designation. If this is the case then the question is fundamentally flawed and needs to be edited and clarified. I think we need more info on the rest of the world that has been created before we can start making too many assumptions. $\endgroup$ – DreadedEntity Jun 12 at 21:17
  • $\begingroup$ Thanks for the insight, guys :-) $\endgroup$ – cal Jun 14 at 18:53
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One other way to get in undetected would be to shoot a great big empty escape pod slowly over an area that is heavily covered in radars, and then send a small pod down somewhere remote. The first escape pod would attract all the attention of the satellites and radars, and they might not notice a little tiny blip off in some dark corner.

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This is an interesting question that made me want to look into the B-2 stealth bomber, but then dicovering that the B-21 Stealth Bomber is coming and very top secret.

https://youtu.be/Tokg7iIvfQk

The above link talks about the B-21 Stealth bomber, and indicates that its own radar capabilities sort of "fill in the gaps" for ground based radar. It can only be detected by infrared sensors at extremly close proximity. The narrator describes it as basically having to search the entire sky looking through a straw. Could it be as simple as having a stealth escape pod which could spoof it's own visibility reporting? Such an elite ship that you descibe could potentially also be the best data collection asset that the ground has to fill in line of sight needed to even track it. Good old fashioned sabotage is always plausable if you were to be launchging from the only thing that could potentially detect the launch. Perhaps timed with a solar flare or some other kind of celestial phenomenon that may give a decent blackout period with an unsuspicious cause for a system black out, the escape pod launches. Introducing some sort of software virus to the motherships system to loop back applicable telemetry prior to the launch/and blackout can keep the launch indefinately indetectable. Sort of like playing a loop of routine security camera footage during the heist.

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  • $\begingroup$ Such techniques could be used against search radar, but the incandescent ball of plasma caused by compressive heating of the air in front of the pod is going to be rather hard to miss as it lights up a substantial chunk of the EM spectrum... $\endgroup$ – Perkins Jun 13 at 22:00
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Telescopes for observing the spacecraft typically have a narrow depth of focus as the magnification increases. If the escape pod can manage to be undetected when it detaches from the spaceship, the further it moves away from the plane of the spacecraft, the harder it is to recognize as an escape pod -- it gets all fuzzy and blurry.

So if the spaceship can rotate so the escape pod is occluded from view of the telescopes until it is out of the imaging plane it will be hard to see.

Also, any telescopes watching it will be tracking the spaceship, so if the escape slows or speeds up it will not be in the field of view of the telescopes watching the spaceship.

Lastly, radar. That's a hard one unless the escape pod is actually hard to detect naturally. As has been pointed out they are made to be found, but maybe that is by the radar reflectors and transponders that are installed in them. If that is the case, removing the reflectors and turning off the transponders can help get the escape pod through the radar net. Then, maybe, they time their departure to coincide with an increase in the space junk field.

From my research for a short story I wrote, the orbital debris is tracked and cataloged, and tied to the launch or vehicle that created it. The catalog is available at NASA if you wanted to pick and reference a specific glob of space metal that escapes pod uses to hide from radar.

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Depending on your level of technology, you might be able to drop vertically, rather than at an angle as re-entry currently does. By use of propulsion and suitable craft design you might be able to do this fairly stealthily.

The mother ship is in orbit (so travelling at, say 17,000 mph ground speed). In order to re-enter, todays craft end up hitting the upper atmosphere at something like that speed, the friction slows them down, and eventually parachutes (or I guess retro-rockets) slow down the decent enough for a touch down that doesn't kill the people inside. It's quite a spectacle to watch, and covers a relatively large amount of the globe.

However, if your escape pod were to use propulsion to reduce its ground speed to near zero, whilst maintaining altitude, then it "only" has about 100km to fall to land on the ground. That fall could further be managed by propulsion such that it caused no excessive heating in the craft (so no 'burning meteor' in the sky), and further more the view of it would be constrained to a relatively small amount of the surface of the earth. This does pre-suppose that you have a means of propulsion that uses a very compact source of fuel and doesn't create a visible 'jet' of propellant like chemical rockets do. You'd also probably want to coat your craft in stealth material and whatnot to thwart radar and other tracking systems.

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1) If the pod is small enough from the viewing perspective, it should escape most forms of detection meant for large ships. So you can try the idea of minimal radar cross-section, basically a needle shaped escape pod.

2) If there is some form of energy fluctuation detection, then you can use randomized impulse thrust to guide the pod. Or even better a one time thrust in the vicinity of the large ship to mask the energy fluctuation.

3) The large ship itself should create a blind spot depending on where the observers are positioned.

4) Disguise the pod as trash can ejected in space, but that depends on status of space garbage in your story. Cuz currently, there are lot of space debris surrounding earth.

5) How about having the people dive individually wrapped in some heat shielding material while carrying some small thrusters/jetpack ? A good way to build tension on who would survive, kill some people, set up some sacrifice scenes, etc. They should be able to land in the ocean undetected because of the tiny size.

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  • $\begingroup$ "How about having the people dive individually wrapped in some heat shielding material while carrying some small thrusters/jetpack ? A good way to build tension on who would survive, kill some people, set up some sacrifice scenes, etc." This is great :-) I couldn't help smiling -- not because it's funny, but because you hit the nail on the head about what goes through a writer's mind. "Hey, who do I want to die/survive in order to move the plot or audience..." Thanks for the feedback! I'm so appreciative of everybody's eagerness to share ideas. $\endgroup$ – cal Jun 12 at 11:57

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