Category Archives for Space

NASA Is Too Good At Science

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NASA released a plan the other day to build a manned space station orbiting the moon. I’ve already seen a lot of talk about how bad a plan it is. And it is a pretty poor plan – but not for the reasons everyone says. A lunar orbiting base isn’t stupid in and of itself. It’s only a bad idea because of how NASA’s doing it. The critics say that this won’t produce enough science. They have it exactly backwards. This station produces too much science – like everything else NASA does.

Understand something important: NASA is really, really good at science. They do a lot of wonderful work. I have friends and family who do some of this work for NASA, and it’s brilliant. But NASA’s focus on science prevents the agency from focusing on what should be its primary mission: making access to space regular, easy, and cheap.

The biggest cost contributor, launch costs, will already fall dramatically over the next ten years. The private space race and companies like Space-X, Virgin Galactic, and Blue Origin, are already winning that battle. Space-X’s rocket system is already far cheaper than competitors, and as they make it more and more reusable it will become even cheaper.

But launch costs still won’t become “trivial.” As such, we’ll need to ensure that we’re using the mass we launch effectively. And the best way to do that – as I’ve noted before – is to build space infrastructure.

That is what NASA’s primary mission should be. Private industry will likely redo everything NASA does on the infrastructure front – and do it better and cheaper. Eventually. But planting the seed of that infrastructure would have huge payoffs.

One core piece of that infrastructure, as I’ve also discussed before, is that a system should be in place for earth-moon transit. And that system should largely consist of a ferry that travels only between two space stations – one in Earth orbit, and one in Lunar orbit. We already have a station in Earth orbit, so NASA’s new lunar orbit station could fulfill the role for the second part of that, right?

Possibly. But it would be a pretty crappy system if we built it that way, even by government standards. Both stations really need to serve two purposes, and only two purposes:

  • They need to be good transfer points to move people, cargo, or better yet, a space equivalent of standard shipping containers from one vehicle to another.
  • They need to be good supply depots, storing air, water, food, and most importantly fuel.

Basically, we need two giant truck stops in the sky.

The ISS is horrible at both of these tasks. It wasn’t built for it – because it was built to do science. And NASA’s new lunar orbit station looks poised to be built for science, also. As others have complained, there’s not enough science it could do to justify the cost.

But if we built it to support infrastructure, then the future science done – not by it, but by those who use it as a layover – could more than justify the cost.

Alas, NASA is too good at science to follow the better path.

Russia Tests Anti-Satellite Weapon

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Who shot down DMSP-13?

CNN tells us tonight that Russia has recently tested an anti-satellite weapon.

The US tracked the weapon and it did not create debris, indicating it did not destroy a target, the source said.

The Russian test, coming as President-elect Donald Trump prepares to enter the White House next month, could be seen as a provocative demonstration of Moscow’s capability in space.

Russia has demonstrated the ability to launch anti-satellite weapons in the past, including its Nudol missile.

Emphasis is mine, and not in the original article. I remain suspicious that DMSP-13 was shot down by the Russians, although it is clearly unconfirmed at this point. Nevertheless, we know that Russia and China both badly want anti-satellite technology. They have invested quite a bit of money and time into various technologies for it. They know quite well that US space technology puts them at a huge strategic disadvantage. Both nations desperately want to eliminate that advantage if at all possible.

CNN strongly implies that Putin used this test to demonstrate capability and intimidate the incoming President Elect. I remain convinced that Russia has done so before, more than once. I have zero doubt that they will do so again.

What’s the right move for the US? Developing countermeasures is expensive and clunky, so that’s probably what we will do. What we should do is focus on lowering launch costs so that we can replace satellites so cheaply that destroying them is of little gain. The current “commercial space race” is already meeting success on that front. We should do all we can to speed the process. Of course, a little bit of space infrastructure wouldn’t hurt, either.

Orbital Insertion and Space Combat Tactics – Part 4

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One issue that is almost universally ignored in science fiction these days is the role of orbital mechanics in space combat tactics. Science fiction space combat tends to be written or visualized as if the spacecraft involved have nearly infinite energy and thrust available. Occasionally this is due to the writers or visual effects technicians consciously simplifying things for viewers. Unfortunately, however, most of the time it’s simply due to the writers being woefully ignorant of the subject.

In Part 1 we showed that any reasonable account of space combat in near-to-medium-future hard sci-fi must account for orbital mechanics. In Part 2 we discussed that pros and cons of higher orbits and lower orbits. In Part 3 we examined cases where our two spacecraft occupied dissimilar orbits. In our final part, we’ll discuss various considerations related to actual maneuvering between orbits.

As we noted back in part 1, the fundamental reason that we must consider orbital mechanics is the massive energy requirements necessary for raw point-to-point travel in space. Current technology and technology that can be extrapolated from known and proven physics are not capable of breaking past these limits. This same factor imposes limits on orbital maneuvering.

There are three fundamental factors that will drive maneuvering of combat spacecraft: mass, thrust, and fuel. All three of these factors are intrinsically related. More fuel means more mass. More mass requires more thrust to move it. More thrust requires more fuel.

At the same time, there are unavoidable trade-offs in modern propulsion technology. To put it bluntly, the more efficient a propulsion method is, the less thrust it produces. Solar sails and ion drives are highly efficient, but they produce low thrust. This makes them possibly great for long distance travel but very poor choices for the quick maneuvering desired by military vessels.

It seems likely that military craft will mostly rely on such non-chemical propulsion for major drive components (ie, for interplanetary travel). Nuclear power seems a particularly likely choice, just as it is on today’s major naval vessels – and for the same reasons. Nuclear power is very efficient, providing quite a bit of energy for a given fuel mass. Unlike many other propulsion sources, however, it can also provide high thrust. This allows for relatively short transit times, such as military vessels will require.

However, even nuclear propulsion is likely to be poorly suited for fast maneuvers. It is highly likely that chemical rockets will be used for maneuvering thrusters. Based on known technology and physics, quick maneuvering is likely to stay the domain of chemical rockets for some time – and chemical rockets require lots of fuel. Lots of fuel means lots of mass. It also means that the spacecraft must be very careful in how that fuel is used, because once it’s gone it’s gone.

A further consideration is that large drive engines also have great potential to be used as weapons – especially nuclear propulsion engines. This was the second reason that the battleships described in “The Fourth Fleet” had main drive engines both fore and aft. This allowed the ships to use them not just for propulsion but also as the main weapon system. An important consideration, however, is that use of this weapon system will also impact the navigation of the vessel itself.

It is also worthy of note that the design choices described herein will be hugely expensive, thus likely limiting this kind of vessel only to major spacefaring powers. As with modern navies, lesser powers will be forced by economics to limit themselves to less expensive military spacecraft. And also much like the world of today, these vessels are extremely unlikely to be common among private owners.

In Part 1 we showed that we must account for orbital mechanics. In Part 2 we discussed orbits of differing altitude and velocity. In Part 3 we’ve discussed retrograde orbits and non-aligned orbits. Here in Part 4 we discussed maneuvering itself in more detail and also discussed some ways in which this will impact spacecraft design.

This series is the beginning of the discussion, not the end. Any discussion that takes place before such warfare is necessarily speculative. Yet we already know many factors that must effect the discussion. Though this discussion will continue for decades and centuries after space warfare becomes common, we are well served by beginning it now.

Orbital Insertion and Space Combat Tactics

Orbital Insertion and Space Combat Tactics – Part 3

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One issue that is almost universally ignored in science fiction these days is the role of orbital mechanics in space combat tactics. Science fiction space combat tends to be written or visualized as if the spacecraft involved have nearly infinite energy and thrust available. Occasionally this is due to the writers or visual effects technicians consciously simplifying things for viewers. Unfortunately, however, most of the time it’s simply due to the writers being woefully ignorant of the subject.

In Part 1 we showed that any reasonable account of space combat in near-to-medium-future hard sci-fi must account for orbital mechanics. In Part 2 we discussed that pros and cons of higher orbits and lower orbits. However, we assumed that both spacecraft occupied the same orbital plane and that they were both orbiting in the same direction. What happens if we change these assumptions?

The first obvious choice is to consider two spacecraft orbiting in opposite directions but in the same plane (aka a retrograde orbit). Assuming that the two spacecraft are orbiting at the same altitude (and hence the same velocity), these spacecraft will only encounter each other twice on each orbit, and then only briefly.

Let’s consider for a moment two spacecraft occupying a Low Earth Orbit – say around 250 miles (such as the International Space Station). Such an orbit makes a full cycle every 92 minutes, which means that the two spacecraft would only be able to engage each other once every 46 minutes. The duration of the engagement would depend upon the range of each vessel’s weaponry. It should be readily apparent that long range weapons are of great advantage in almost all space encounters. They clearly show their advantage here.

In this particular scenario, weapons with a high burst rate but a long down time become tactically useful. For example, an energy weapon that requires a long time to charge but packs a major punch when fired might actually be practical in this case – provided it can be charged in less time than it takes to encounter the adversary again.

Likewise, shielding that holds up well to burst fire but doesn’t do well under sustained bombardment would be very useful here. The real world offers scant examples of this, but science fiction is littered with various energy shields that exhibit this exact characteristic. Just like our hypothetical energy weapon above, these shields could recharge in between engagements and provide protection.

A military ship equipped with these kinds of weaponry, then, might deliberately choose to enter a retrograde orbit relative to its opponent. On the other hand, a vessel with poor burst capability but built to take a beating might prefer to match orbits and slug it out.

Polar Orbit

Polar Orbit

Alternatively, our spacecraft might choose to enter an orbit with an entirely different angle of declination compared to our opponent. The extreme example would be to have one craft in a polar orbit while the other vessel occupies an equatorial orbit. In this case, the orbits would be angled at 90 degrees to one another.

It is critical to observe that even though the orbits intersect each other twice on every pass, due to orbital timing the spacecraft themselves might never actually encounter each other on these orbits. This is true whether the relative angle is 90 degrees or 1 degree.

This kind of configuration would favor a spacecraft that has both plenty of fuel for maneuvering and a very advanced navigational computer. Very careful maneuvering – consisting of burns to speed up and slow down ones orbit (and by consequence, raise and lower the orbit) could precisely control the timing of the orbital intersections. Depending upon the goals of the maneuvering craft, this could be used to either ensure that the two craft do meet or to ensure that they don’t. Of course, if the adversary also has high maneuvering capability and desires the opposite goal then the game is now on to see which captain can outsmart the other!

Equatorial Orbit

Equatorial Orbit

This kind of scenario absolutely requires a strong navigation computer. What you will not see here is the typical Hollywood scene of a captain standing on the bridge ordering a maneuvering burn “now!” Instead, humans would instruct the computer on the desired goals and the computer would control the timing of the burns. Human beings would not be able to manually control the burns so as to achieve such delicate timing.

This scenario would also favor two distinct kinds of vessels. Spacecraft with major weaponry designed to disable or destroy an opponent instantly or very quickly would find this kind of approach advantageous. Likewise, poorly armed but highly maneuverable spacecraft would find this configuration an ideal way to avoid encountering an enemy altogether. Although there are many others who might adopt this, one might find it useful to think of the first group as “pirates” and the second group as “smugglers.”

Finally, we must also consider highly elliptical orbits. Like angled orbits, elliptical orbits alter the timing and locations when two spacecraft would actually encounter one another. The timings and breakdowns become very complex. Are both orbits elliptical or is one circular? Are the two elliptical orbits aligned or are they angled with each other? Or are they in the same plane, but skewed? The possibilities quickly become very complex, but the considerations are essentially the same as discussed above with orbits of differing angles. Once more, an advanced navigation computer becomes essential to even have a prayer of tactically controlling the encounter.

In Part 1 we showed that we must account for orbital mechanics. In Part 2 we discussed orbits of differing altitude and velocity. Here in Part 3 we’ve discussed retrograde orbits and non-aligned orbits. In Part 4 we’ll discuss maneuvering itself in more detail.

Orbital Insertion and Space Combat Tactics

Orbital Insertion and Space Combat Tactics – Part 2

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One issue that is almost universally ignored in science fiction these days is the role of orbital mechanics in space combat tactics. Science fiction space combat tends to be written or visualized as if the spacecraft involved have nearly infinite energy and thrust available. Occasionally this is due to the writers or visual effects technicians consciously simplifying things for viewers. Unfortunately, however, most of the time it’s simply due to the writers being woefully ignorant of the subject.

Figure 1

Figure 1

We left Part 1 with a discussion of the lunar transit orbit shown in Figure 1. Specifically, we showed that we must account for orbital mechanics. Here in Part 2 we will examine specific orbital decisions and how they effect our space combat tactics.

Transit Speed is our baseline. A spacecraft traveling through this orbit at Transit Speed will, left alone, continue into a “figure eight” orbit. A civilian spacecraft traveling an energy efficient path might adopt something like this approach. Depending on the goals of the civilian craft, it would most likely follow the standard Apollo model described in Part 1 and execute a burn somewhere around Point 4 to transition into a solid lunar orbit.

Keep in mind that these positions are relative and in constant flux. An enemy spacecraft in lunar orbit could be at any point along that orbit. However, that position is eminently predictable for a non-maneuvering spacecraft. If we know its position at time t, we can calculate its position at time t + x. But predictable doesn’t mean convenient. It may well be that the timing of our own orbital insertion coincides with the enemy craft being positions near Points 5 and 7. In this case, our military craft would also have to execute a burn to insert itself into a true lunar orbit as well or else it would never actually encounter the enemy vessel.

The timing of this burn carries a great deal of significance, however, and it’s greatly dependent upon our spacecraft’s velocity along the transit path through Point 3. At Transit Speed or above, we’ll have to execute a breaking burn to slow the craft down. At Low Speed, we’ll have to execute an acceleration burn to speed the craft up.

Beyond that, however, is another consideration. Merely inserting ourselves into the same orbit as our adversary isn’t enough. This point is key: any two spacecraft traveling in the same orbit are necessarily traveling at the same velocity. If their velocities are not the same, their orbits will change. This is counter-intuitive to many, but it is a necessary mathematical consequence of orbital mechanics. The military consequence of this is that once two spacecraft are in the same orbit, their relative positions on that orbit will never change.

Suppose for example that I insert myself into lunar orbit at Point 4. At the time I insert into orbit, my opponent is at Point 8. Unless one of us executes another maneuver, we will continue to orbit in that same relative position to each other – separated by more than a third of the circumference of the orbit – until our orbits decay. We will never encounter each other.

There are two solutions to this problem. The first is to adjust our velocity during the transit through Point 3. Speeding up or slowing down here will adjust the timing of our arrival, and by timing it appropriately, we can then ensure that we enter orbit close enough to our adversary to engage. The downside to this approach is that our opponent will see us coming and has a chance to adjust his own orbit to throw our timing off.

The other option is to enter a higher or lower orbit than our adversary. Here, we face another trade off that has tactical significance. Just like a modern air battle, we will find that altitude and speed are our friends. All else being equal, a higher altitude orbit is better. Likewise, all else being equal a faster orbit is better.

Unfortunately, all else is not equal and we can’t have both. The mathematics of orbital mechanics is a brutal dictator that we cannot escape. The catch is that absolute velocity and relative speed of motion are not the same things in orbit. If I move into a lower orbit, my absolute velocity will be increased. This is necessary to offset the higher force of gravity at the lower altitude. I will actually complete an orbit in less time than my higher orbiting adversary. The reason is apparent: even though I am actually traveling more slowly, the distance I must cover to complete an orbit is far less than that of a higher orbit.

As an example, the International Space Station orbits in Low Earth Orbit (LEO) at roughly two hundred and fifty miles and completes an orbit in 92 minutes. By comparison, a geostationary satellite orbits at an altitude of roughly twenty-two thousand miles and completes one orbit in 24 hours.

If I want to catch up to my adversary, then, one solution is to insert myself into a significantly lower orbit than him, come around behind him, and then raise back up into his orbit. This requires inserting myself at the correct orbit point, decelerating (perhaps substantially, depending upon my transit speed) to enter the low orbit, and then accelerating again at the correct time to enter his orbit.

This maneuver has distinct advantages over simply re-timing my insertion into his own orbit. First, it’s less predictable. That means that our adversary has a harder time responding to it. Second, it leaves us with more leeway to correct for any evasive maneuvers our opponent does do. Third, assuming that we’re orbiting in the same direction, it allows me to come up behind him. Yes, in space he can easily turn to face me without sacrificing his orbit.

But that maneuver does actually sacrifice some maneuverability. This is one reason, among many, that the battleships I described in my story “The Fourth Fleet” had main drive engines on both the fore and the aft of the ship. In addition to being able to accelerate or decelerate without turning, the ships maintained an ability to change to either a higher or a lower orbit without turning. Designing a craft this way would be hugely expensive, much like today’s supercarriers, but it would have huge military advantages.

The final maneuver that we could attempt would be to insert myself into a higher orbit than my adversary and let him catch up to us. Then we could descend into his orbit to engage. With a typical ship configuration, however, this could mean letting him approach our rear or sacrificing orbital maneuverability. However, the configuration I just described above could easily handle this without such a sacrifice. In a situation where, say, I was inserting myself into orbit at Point 4 while my opponent was at Point 5, this might allow me to engage him much faster than otherwise.

This puts my opponent is a position of having a higher apparent relative speed, but it leaves me in a higher altitude orbit and with a higher actual velocity, both of which might be advantageous if used properly. One way that a higher orbit is tactically advantageous is that projectile or missile weapons don’t have to accelerate to reach our opponent – instead they would decelerate, and correct timing might mean that they don’t even have to do that. Kinetic weapons (bullets, shells, railguns, etc) might especially benefit from this, as the higher absolute velocity of a higher orbit would impart a higher raw kinetic energy into our projectile. Meanwhile, these same factors would work against our opponent, reducing the kinetic energy of his projectile weapons and requiring extra acceleration for them to even reach our orbital altitude.

As noted above, the exact way in which these factors trade off tactically is dependent upon the design of both our own spacecraft and our adversary’s. In some ways, we can design the craft to neutralize disadvantages of one position or another (energy weapons, such as lasers, would not suffer from the kinetic energy or acceleration problems imposed by a lower orbit). We can also design our spacecraft to amplify the benefits of one position or another (heavy use of railguns, for instance, could capitalize the benefits of a ship designed to operate at a higher orbit), although we must keep in mind that this would also have the effect of amplifying the drawbacks of poor positioning.

In Part 1, we spelled out why we must account for orbital mechanics in space combat tactics. Here in Part 2, we saw how decisions of particular orbits have a large effect on those tactics. In Part 3 we’ll examine some alternative orbits and see how those can drastically alter the tactical situation.

Orbital Insertion and Space Combat Tactics

Orbital Insertion and Space Combat Tactics – Part 1

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One issue that is almost universally ignored in science fiction these days is the role of orbital mechanics in space combat tactics. Science fiction space combat tends to be written or visualized as if the spacecraft involved have nearly infinite energy and thrust available. Occasionally this is due to the writers or visual effects technicians consciously simplifying things for viewers. Unfortunately, however, most of the time it’s simply due to the writers being woefully ignorant of the subject.

There are a few cases where orbital mechanics can be safely ignored. Obviously, they can be ignored for atmospheric combat. Modern science fiction fans are intuitively familiar with atmospheric combat thanks to watching hours worth of dogfights in film and television. Although many of the details would make a hardened fighter pilot squirm, our intuitions of the basic physics of how these fights occur more or less conforms to reality. They can also be safely ignored when we’re discussing ships traveling in interstellar space (although there are other issues there, mainly the massive velocities of the spacecraft themselves). And in some cases of two “mother ships” occupying very near orbits, we can handwave away orbital mechanics if the fight is focused on “fighter ships” surrounding them. The mechanics still don’t go away, but for the purposes of entertainment we can safely pretend that they do.

Otherwise, orbital mechanics are crucial to space combat tactics. The definitive primer on orbital mechanics for science fiction writers is Ken Burnside’s magnificent essay “The Hot Equations.” Anybody looking to study the matter seriously should start there. Rather than retread ground he has already covered, my intention is to break new ground and discuss some of the implications of the physics discussed by Mr. Burnside.

My endeavor here will be far more modest in scope than Mr. Burnside’s. I wish to discuss merely one element of an entire tactical encounter: orbital insertion. Mr. Burnside has already lain much of the groundwork that we’ll need. Rather than walk through all of his logic, I wish to begin merely by recapping some of his relevant conclusions.

  1. Change in velocity (delta-V) is a finite resource, and it’s of huge importance militarily.
  2. Hiding a spacecraft (stealth technology in space) is essentially impossible because of the heat generated by the thing (even under minimal power) compared to the unrelenting background cold of space.
  3. Because that heat is detectable as infrared light, range of detection is limited really only by the strength of the sensors. In other words, sufficient sensors can detect a spacecraft at a range close enough to infinity as to not matter, militarily speaking.
  4. Thrust is necessary to effect delta-V. In other words, if a spacecraft wishes to alter course, it must emit thrust of some kind.
  5. Thrust is detectable. If that spacecraft changes course, it can’t hide the fact from its adversaries.
  6. You can’t make a battleship look like a rowboat in space. The heat signatures will give away the game.

Let’s begin by synthesizing these ideas together into their logical conclusions. Orbital mechanics require that course corrections (requiring detectable thrust) be made, very often at distances that are detectable in time for adversaries to effectively counter-maneuver. Let’s look at why this is.

Figure 1

Figure 1 represents a lunar transfer orbit of the type used by the Apollo missions. Keep in mind that this is, in space terms, a small distance to travel. Nevertheless, it can illustrate many of our points quite nicely.

For those unfamiliar with the basics of orbital mechanics, here’s how it basically worked for Apollo. The circles represent the Earth (the larger circle in the lower left) and the moon (the smaller circle in the upper right). The Apollo spacecraft launched on board a giant Saturn V rocket from Point 1 and first entered into a Low Earth Orbit (LEO), represented by the circle around the Earth.

At the appropriate time and place – Point 2 – the Apollo spacecraft executed another engine burn. Here on Earth, that would have been equivalent to simply pointing the car in a given direction and then hitting the gas. The car goes straight until you hit something or run out of gas. Space is different. The spacecraft goes straight until either you hit something or some gravity source operates on it. In this case, the gravity source is the moon – and rather than going straight, the Apollo craft was now on a “figure eight” orbit that orbited both the Earth and the moon. In Figure 1, that orbit would go from Point 2 to Point 4, around the moon to Point 8, then back to the Earth at Point 9 and around to Point 2 again. Assuming no orbital decay (which is a big assumption, and very likely incorrect) it would perform this orbit again and again and again. Apollo 13 actually did almost exactly that, performing only mild course correction burns, in order to get the astronauts home as quickly as possible after the spacecraft was damaged.

But Apollo 13 wasn’t designed to do that. The intention was to do what Apollos 8, 10, and 11 had done, and what the later Apollo missions would do. In the successful missions, another “braking” burn was performed at Point 4 on the chart to slow the spacecraft down. Doing so altered the orbit, and transferred it into a pure lunar orbit – the circle you see around the moon. But without the burn, you get the figure eight orbit.

Had the Apollo craft been traveling at different speeds, the results would have been radically different. Just a bit faster or slower, and the craft still would’ve traveled past the moon and swung around back toward Earth – but its aim would have been off. It would have missed the Earth, reached escape velocity again, and been slung off into interplanetary space.

If it had gone a lot faster, it wouldn’t have even swung back toward Earth. Its path would have arced a bit, thanks to the moon’s gravity, and then it would have just kept going – once more headed for interplanetary space. Had it been going fast enough, the moon’s gravity would barely have even warped its trajectory.

The speed of the spacecraft during the transit stage (roughly point 3 on the chart) is of critical importance. Let us consider six categories of speed:

  1. Very Low Speed – the spacecraft is unable to escape Earth orbit and never transits to the moon at all.
  2. Low Speed – the spacecraft does not have enough velocity to enter a full figure eight orbit, and will likely crash into the moon.
  3. Transit Speed – the spacecraft is paced exactly right for a figure-eight orbit.
  4. High Speed – the spacecraft will swing around the moon and return, but at too high speed to re-enter Earth orbit
  5. Very High Speed – the spacecraft will have its trajectory warped by the moon, but will continue beyond it rather than orbiting it at all.
  6. Ludicrous Speed – the moon’s gravity has an imperceptible effect on the spacecraft’s trajectory.

For our purposes, we can ignore Very Low Speed, as it won’t even allow us to maneuver to fight an enemy spacecraft near the moon. We can also safely ignore Ludicrous Speed for all “hard” science fiction scenarios. Any technology that could be built on currently understood physics or engineering can neither accelerate to Ludicrous Speed nor decelerate from it in anything we would consider a reasonable, militarily significant time.

From a military standpoint in a reasonable hard sci-fi scenario, we must therefore assume a spacecraft operating at Low Speed, Transit Speed, High Speed or Very High Speed. We must also assume that the craft will ultimately need to either a) match orbit with an enemy spacecraft in order to fight it, b) make a flyby close enough to launch a barrage at the enemy, or c) enter an eccentric orbit designed to close with the enemy more than once for repeated barrages.

In nearly all cases, this will require our hero spacecraft to make further burns and expend delta-V. The speed at which the craft makes the transit and its decisions of when, where and how quickly to expend delta-V has massive tactical implications. Writers of hard science fiction – and potential future space combat officers – would do well to keep these in mind.

In part 2 we will begin to examine the ramifications of these decisions.

Orbital Insertion and Space Combat Tactics