Jeffrey LewisBombs From Space

Christopher Stone, “a space/missile officer with Air Force Space Command-Reserve Component”, has written an article in the Space Review blaming “certain circles” and “political” reasons for the lack of orbital strike weapons.

Stone omitted, as a reason, the laws of physics, which presumably also hate our freedoms.

Fortunately, David Wright and Laura Grego have penned a response elucidating those relevant laws:

Briefly, for a space-based weapon to be able to reach a ground target rapidly, it must be positioned close to the ground, in low Earth orbit (LEO) at an altitude of several hundred kilometers. However, satellites in LEO move quickly with respect to the ground, and to ensure that one is in the right place at the right time, a constellation of many satellites would be necessary. Timeliness and number of satellites required play off of each other, but to be competitive with ground-based systems and have a response time of about 30 minutes, one would need some 100 satellites in orbit. Those 100 would provide for a single satellite to cover a target; to have two-on-one targeting or allow two nearly simultaneous attacks on nearby targets would require doubling the size of the constellation, and so on.

While Mr. Stone correctly notes that three satellites in geostationary orbits (GEO) can view the entire equatorial regions of the earth, GEO satellites are 100 times farther from the earth than LEO satellites—much too far to be able to strike the ground rapidly. In reality, space is already used for those tasks it is best suited to, and not those it isn’t. Basic physics dictates this.

Moreover, the intuitive appeal that bombing from space has for many people—that weapons can be “dropped” from above a target—is simply wrong. Objects in orbit stay in orbit unless there is a force to push them back toward the ground. Not only do orbiting ground-attack weapons require a large rocket to get them into space in the first place, they must carry large amounts of fuel (essentially another rocket) to accelerate them back out of their orbit and down to earth. Since launching mass into orbit costs oughly $10,000 per pound, such a constellation becomes very expensive. Moreover, since the weapons and their rockets are orbiting in space for years, reliability becomes a concern.

David and Laura were much more moderate in tone that I was, after Taylor Dinerman incorrectly reasoned that intercepting a missile in the boost phase would cause the warhead to “fall back on the nation that launched the missile”.

For the full scoop of orbital strike weapons and other flights of fancy, check out Wright, Grego and Gronlund, The Physics of Space Security.

Late Update: I overlooked a great report by the late Bob Preston and his colleagues at RAND.


  1. Ken Sitz (History)

    And what about ‘Space Frogmen’? The call for orbital strike weapons reminded me of the lurid pulp of Jeff Sutton’s “Bombs in Orbit” (Ace 1959). THEY never had this problem with their physics! 🙂
    Best Regards,

  2. yale

    In 1958, President Eisenhower approved the report of advisory Purcell Panel which stated:

    Much has been written about space as a future theater of war, raising such suggestions as satellite bombers, military bases on the moon, and so on. For the most part, even the more sober proposals do not hold up well on close examination or appear to be achievable at an early date. Granted that they will become technologically possible, most of these schemes, nevertheless, appear to be clumsy and ineffective ways of doing a job. Take one example, the satellite
    as a bomb carrier. A satellite cannot simply drop a bomb. An object
    released from a satellite doesn’t fall. So there is no special advantage in being over the target. Indeed the only way to “drop” a bomb
    directly down from a satellite is to carry out aboard the satellite a rocket launching of the magnitude required for an intercontinental
    missile. A better scheme is to give the weapon to be launched from the satellite a small push, after which it will spiral in gradually. But
    that means launching it from a moving platform halfway around the world, with every disadvantage compared to a missile base on the
    ground. In short, the earth would appear to be, after all, the best
    weapons carrier.

  3. yousaf (History)

    just fyi, the whole document yale refers to above can be found at pp. 118—>126 of:

    other fun doc’s in there too…

  4. Andy (History)

    You know, it would be a lot easier if they just put those things in a polar, low earth, geosynchronous orbit. All you’d need are some impulse engines to move your photon torpedoes around to where you wanted to fire them. I know it’s possible – I saw it on TV!

  5. Dick (History)

    With all due respect to David and Laura, perhaps the best discussion of the technical challenges associated with space-to-earth weapons was done a few years ago by RAND’s Project Air Force. It’s available for download at:

    The RAND report is written in a deliberately neutral tone. However, it’s worth noting that the report was sponsored by the late Lt Gen Roger DeKok, who was one of the Air Force’s smartest space generals.

  6. Buck Rogers

    George the Younger, with Big Dicks approval, could be sold on a combined GPS/Nuclear Rocket launching system by Boeing Aerospace used car sales experts. The rockets could be nuclear reactor powered with mrv heads.

  7. Haninah

    This may be a good time to cross-link to’s ongoing series about the hafnium bomb and other imaginary weapons.

  8. Monte Davis (History)

    Based on acquaintance with the SDI crowd twenty years ago as well as some Space Command people today, it seems to me that the Stone piece (and “high ground” arguments ever since 1957) are simply a military instance of the broader phenomenon of “selling space”: first comes the underlying impulse of We Gotta Get Out There and Do More, and on top of that a layer of rationalization: we gotta protect our milspace assets (or hit Tora Bora with “rods from god”)… we gotta get clean energy from SPSats or lunar He3… we gotta be ready to stop the planet-killer asteroid, etc.

    It’s not that these selling points are specious—as a cold-eyed space enthusiast, I believe most or all of them will come true eventually, and there’ll be “space lanes” with enough strategic importance to justify the Mahan-ish rhetoric. It’s just that because the underlying impulse is transcendent and…let’s say not irrational, but non-rational… the sellers don’t test them against the same criteria of cost, timing and ROI that are routinely applied to non-space initiatives.

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