Index The Garwin Archive

                    _____ ___________ ____ ___ _______


                            Richard L. Garwin

                          IBM Research Division
                     Thomas J. Watson Research Center
                               P.O. Box 218
                        Yorktown Heights, NY 10598

                              (914) 945-2555

                      Adjunct Professor of Physics,
                           Columbia University;

                         Adjunct Research Fellow,
                       Kennedy School of Government
                           Harvard University)

                             December 3, 1988

                        WAYS OUT OF THE ARMS RACE
                Second International Scientists Conference
               "From the Nuclear Threat to Mutual Security"

                             London, ENGLAND

       ABSTRACT. Widespread myths distort our understanding and in-
       hibit  valuable programs to apply space to civil and to non-
       weapon military purposes.   Six so-called  "&Delta.V  myths"
       are  discussed  in this paper, three of the dealing with SDI
       and space weapons, and three relevant to reusable launchers,
       space stations, and laser-powered  satellite  launch.    Two
       non-&Delta.V  myths  (survivability of defensive satellites,
       and the utility of manned space  flight)  complete  the  se-
       lection.   Scientists have a special role to play to educate
       the public and decision makers if we are to make  safer  and
       more rewarding public choices in our use of space.

       326>STMP            112188STMP DRAFT 11             12/15/88
              Views of the author, not of his organizations


       A perceptive American saying goes, "It isn't  so  much  what
       you  don't know that can hurt you; it's the things you think
       you know that are not so."  One modern example is the set of
       myths and taboos that have arisen in recent decades  in  re-
       gard  to  the  use of space for civil and military purposes.
       These rise above simple misconceptions, and  spread  through
       political  and  journalistic  channels, often with resulting
       benefit to some special interest but with detriment to  both
       efficiency  and economy.  Some of these myths drive the arms
       race by, for instance, exaggerating the threat that would be
       posed by nuclear weapons in  orbit,  or  the  capability  of
       space-based  defenses.    But if we are able to find our way
       out of the arms race it will be good also to be clear headed
       about non-weapon and civil uses of space.

       While the Strategic Defense Initiative (SDI)(1)  is  associ-
       ated  with  some of these myths, others impede our civil and
       military non-weapon use of space.  That myths are not benign
       can be seen in the case of the SDI.   According to  Paul  H.
       Nitze,  President  Reagan's  chief arms control advisor, and
       President Reagan himself,(2) to be considered for deployment
       SDI must be (1) militarily effective, (2) adequately surviv-
       able,  and  (3) cost-effective  at the margin.  If not, then
       SDI can compel an offensive arms race rather than quench it;
       it can provoke nuclear war rather than prevent it.    There-
       fore,  even  the attractive myth (if such it were) of effec-
       tiveness, survivability, and  low  cost  for  SDI  would  be
       downright dangerous.

       On  the civil side, NASA has focused on the space shuttle as
       the most efficient launcher to low earth orbit (LEO), and on
       a space station  for  performing  science  and  other  space
       missions of the early 21'st century.  At $10 billion and $30
       billion respectively, a wrong guess could be disastrous.  In
       fact,  the erroneous claims about the cost and efficiency of
       the space shuttle as launcher have already had a  disastrous
       effect  on the US civil and military space programs, punctu-
       ated and slightly only slightly worsened by  the  Challenger
       catastrophe  of  January, 1986.  Indeed, had it not been for
       the destruction of the  space  shuttle  Challenger,  the  US
       might  still be saddled with the sacred cow of the high-cost
       space-shuttle-only access to space.

       What can we say, with generality and simplicity,  about  SDI
       and  shuttles  and  space stations?   I will discuss in some
       quantitative detail two general kinds  of  myths--  &Delta.V
       myths  and  non-&Delta.V myths (that is, myths that do or do
       not involve centrally the "delta-V" or change of velocity of
       a payload or satellite).  I leave for the final  section  of
       this paper the discussion of the origin of such myths and an
       attempt to evaluate their cost.  The list follows:

       1.  &Delta.V myths.

           a.  Offensive-defensive mass ratio in SDI.

           b.  Railguns vs. rockets for space-based intercept.

           c.  The pop-up anything for boost-phase intercept.

           d.  The problem of reusability of satellite launchers.

           e.  The myth of the equatorial space station.

           f.  Laser-launch of rockets and satellites.

       2.  Non-&Delta.V myths.

           a.  Survivability  of  satellites  for  defense  against
               ballistic missiles.

           b.  Man in space.

       3.  Lessons learned.

         DELTA-V MYTHS.

       All existing or planned satellite launchers or rockets oper-
       ating in space are propelled by the continued  expulsion  of
       mass  from the vehicle at high speed, communicating an equal
       and opposite impulse  to  the  vehicle.(3)  Essentially  all
       rockets  thus  far  function  by  creating hot gas in a com-
       bustion chamber, and expanding the gas through a nozzle into
       the vacuum of space, to form a directed  jet,  thereby  con-
       verting  with  almost  100% efficiency the thermal energy of
       the gas to kinetic energy of the gas along the axis  of  the
       nozzle.  What is the efficiency of conversion to kinetic en-
       ergy  of  the  payload in orbit?   Asssume a small amount of
       mass &Delta.M is ejected to the left from  the  vehicle,  at
       exhaust velocity Ve.  Eq. 1
                     dP/dt = 0 = +Ve&Delta.M + M&Delta.V        (1)

       states  that  the overall momentum P of the universe remains
       constant, in that the sum of the  momentum  of  the  ejected
       mass  and  the increased momentum of the spaceship of mass M
       (due to its increased velocity as a result of the  expulsion
       of  the gas) remains zero in the reference frame moving with
       the spacecraft before the mass was ejected.  Eqs. 2

                       dV/dM = -Ve/M, dV/Ve =  -dM/M,           (2)

          &Delta.V/Ve = -&Delta.ln M; Mo/Mf = e&Delta.V/Ve

       relate the  increase  of  spacecraft  speed  with  the  mass
       ejected,  and the initial mass of the rocket Mo to the final
       mass Mf, with the velocity gain &Delta.V and the exhaust ve-
       locity Ve.  Apparent from this equation, as is  well  known,
       is  that  velocities  very much greater than Ve can't be ob-
       tained in a single-stage rocket because of the mass  of  the
       "tanks"  and  of  the rocket nozzle, which must be sized for
       the rocket launch mass and initially massive propellant flow
       rate.   Accordingly, long-range  missiles  and  rockets  for
       launching satellites to low earth orbit (LEO) are staged, so
       that  large  tanks and engines are discarded early in flight
       rather than being carried to the final high speed.   By  the
       use  of  this "rocket equation" one can follow in detail the
       staging process, including the use of fuels  with  different
       "specific  impulse"  on successive stages, nozzles with dif-
       ferent expansion ratio, and different tankage mass fraction.

       That would carry us too far afield here, and I  summarize  a
       very useful reference(4) by asserting that Eq. 2  represents
       the  required  mass  ratio well enough if Ve is reduced from
       the 3 km/s typical of good solid-fuel rockets to  an  effec-
       tive Ve' of 2.5 km/s, to compensate for the lack of explicit
       consideration of penalties due to tankage and engine mass.

       The  specific  impulse of a propellant, Isp, is defined as a
       time--  the  reciprocal  of  the  mass  expulsion  rate   of
       propellant  supporting  unit  mass  against  gravity  at the
       Earth's surface, in the rocket arrangement  provided.    The
       rate  of  expulsion E of mass required to support a constant
       mass M is dP/dt = Mg = EVe, from which it is clear that

       Isp == M/E = Ve/g.

       Furthermore, a rocket can do no better than  to  expand  the
       hot  gas  from  its combustion chamber "fully" so that it is
       essentially a cold stream moving at speed Ve along the  axis
       of the rocket nozzle.  To do this requires a relatively long
       nozzle,  with  a  large area ratio, so that the pressure and
                               ____ ______
       hence the internal energy of the gas is reduced  and  almost
       all of the initial thermal energy is converted into directed
       kinetic energy.  Thus the performance of a rocket is bounded
       by  the  conversion  of  all  of  the chemical energy of the
       propellant per gram, Ec,

       into kinetic energy of the uni-directional cold-gas stream

       as determined by 1/2 Ve2 = Ec.

       Taking a nominal 1000 cal/g energy content(5) for  high  ex-
       plosive  (which  has  properties  not necessary for a rocket
       fuel),  one  can  compute  the  Ve  for  high  explosive  as
       2.893 km/s.

       We are now ready to explore the &Delta.V myths.

         Offensive-defensive Mass Ratio.

       Since  before  there  were  ICBMs, thought has been given to
       antiballistic missile systems (ABM) involving orbiting  kill
       vehicles.    Clearly,  an  orbiting vehicle striking an ICBM
       booster or warhead in space would do so with collision speed
       comparable with orbital speed of 8 km/s.  We have just  seen
       that  high-explosive  energy per gram corresponds to a speed
       of 2.9 km/s, so that an orbiting mass without warhead strik-
       ing a stationary object of larger size would deliver  to  it
       (8/2.9),  or about 7.6 times the energy of an equal mass of
       stationary high explosive.   Thus, space-based  interceptors
       can kill effectively with their kinetic energy alone-- hence
       the name Kinetic Kill Vehicles or KKV.

       The SDI Organization (SDIO) as recently as November  1988(6)
       emphasizes  that the destruction of ICBMs and SLBMs in boost
       phase is critical and can be carried out  only  by  orbiting
       KKVs  (space-based  interceptors  or  SBI),  until directed-
       energy weapons (DEW) are available at some later date.   The
       SDIO  program goal, however, has been to provide KKVs with a
       homing "head" of 5 or 10 kg mass.  Even if the SDIO were  to
       achieve  its goal, such a system would not satisfy the Nitze
       criteria of cost-effectiveness at the margin, and  hence  it
       would  not  be a desirable system to deploy, as indicated by
       the following analysis:(7) The rocket equation is  important
       in  determining the mass of the defensive system required to
       counter a current offense.    For  instance,  discussion  of
       'near-term  deployment'  of  SDI would achieve the essential
       boost-phase intercept within the boost-time T of  the  ICBMs
       by  basing the SBI on space garages.  Those garages in their
       90-minute orbits of the Earth which are in the  vicinity  of
       the  Soviet  Union could contribute an SBI out to a distance
       from the garage of T multiplied by &Delta.V, and although by
       appropriate choice of orbit the density of garages over  the
       Soviet  Union  could be increased about a factor 3 from that
       of uniform coverage of the Earth's surface,  that  is  about
       the  best  that  could be done.  Since the area which can be
       reached by an SBI from  a  garage  is  proportional  to  the
       square  of this outreach distance, the minimum number of ga-
       rages goes inversely as the square of the SBI velocity-gain.

       If there is a homing warhead mass Mf  required  (at  present
       15 kg  for the small homing warhead of the US aircraft-based
       ASAT, after the two-stage rocket falls away which brings  it
       to  orbital altitude), the initial mass of the SBI housed in
       the garage is given again by Equation 2,  in  terms  of  the
       homing  warhead mass and the required velocity gain from the
       garage.  One can reduce the mass of a given  SBI  by  having
       only  a small velocity gain, but then a lot of SBI will have
       to be placed on orbit in many garages  in  order  to  ensure
       that  the required areal density of SBI will be available to
       handle the boosters.  Because the boosters in flight are not
       spread uniformly, one must  provide  an  SBI  areal  density
       which  at  every point can equal this maximum required.  The
       number of SBI on orbit thus increases as the  reciprocal  of
       the  area  to  which an SBI can be dispatched from its space
       garage, so that the total mass of SBI on orbit has an  expo-
       nential factor from Equation 2, and an inverse square factor
       in velocity gain as just indicated.

       SBI   area   coverage:      If  Ao = &pi.n(T&Delta.V),  and
       n &approx. (1/&Delta.V),

       mass on orbit  = Mf n e&Delta.V/Vc, proportional to (e&De(3)

       Equation 3 shows that the mass on orbit is  minimized  at  a
       velocity  gain  equal  to  twice the escape velocity or some
       6 km/s.  Actually, since the SBI must descend from their or-
       bital altitude to intercept the boosters, far more  SBI  are
       required than indicated.

       Calculations(8) show that only 13% of the orbiting  SBI  can
       in any way attack either the SS-18 booster or its post-boost
       vehicle,  (2.5%  in  boost  phase, 10% against the MIRV bus)
       while only 2.3% could attack the Soviet SS-25.  Furthermore,
       if the Soviets continue with the 10-warhead  SS-24  but  use
       instead  a  6-warhead  'minibus' only 1.9% of the KKVs could
       attack the SS-24, compared with  9.5%  against  the  current
       version SS-24.

       In  summary, a 15-kg homing kill vehicle would require about
       300 kg SBI housed on the garage, with a garage  mass  total-
       ling  some  500 kg per SBI (including the SBI itself).  This
       is more than the weight of a nuclear warhead  (some  300 kg,
       including  reentry vehicle), and if 10 percent of the SBI in
       flight can reach a booster or RV, this is  the  minimum  re-
       quired  against  a  10-MIRVed missile to be effective in de-
       stroying boosters carrying 10 MIRVs instead of warheads.

       With only 2% of the SBI capable  of  boost-phase  intercept,
       even   a   10-warhead  booster  cannot  be  destroyed  cost-
       effectively in this way, and a single-warhead offensive mis-
       sile certainly cannot be.

         The Myth of the Rail-gun Advantage Over the Rocket.

       A "rail gun"  is  simple  in  concept--  an  electromagnetic
       launcher in which the projectile slides between two metallic
       rails  and  conducts  a  large  current  between  them as it
       slides; the accelerating force is  provided  by  the  inter-
       action  of  the  current with the magnetic field provided by
       that same current in the rails.   The SDIO has  funded  rail
       gun development and power supplies for space-based intercept
       as  an  alternative to rocket propulsion, and in a speech in
       October, 1984, Gen James A. Abrahamson stated that "chemical
       propulsion" (rockets) would prevail up to  speeds  of  about
       5 km/s,  but  that  the  region above 5 km/s belonged to the
       rail gun.  What must the rail gun  accelerate  in  order  to
       help  do  the  SDI  job?   If it is to operate at a range of
       2000 km  (call  it  2 megameters  or  2 Mm),  and   if   the
       projectile  flies  at  10 km/s,  it will take 200 seconds to
       reach its target.   During that  time,  an  ICBM  moving  at
       7 km/s  would have moved 1400 km, so that it is very clearly
       necessary to project a homing head and not  an  inert  "bul-
       let."   In comparison with the rocket-propelled head, no as-
       pect of the rail gun propulsion would allow the head  to  be
       made  smaller and lighter than the rocket head.  In fact, if
       rail-gun acceleration is to be limited to 10 g (so that the
       force on a 10-kg homing head would be "only" 1000 tons  dur-
       ing acceleration), the rail gun would be 50 m long.  A typi-
       cal rocket-propelled SBI would have an acceleration of 20 g,
       so that the force on the homing head would be less by a fac-
       tor  5000.   Clearly, the high acceleration forces of a rail
       gun pose serious design constraints on the  homing  technol-
       ogy.   Furthermore, multiple SBIs can be launched simultane-
       ously from  an  orbiting  garage,  whereas  the  substantial
       investment of a rail gun and power supply would be amortized
       over  sequential launch of multiple homing projectiles, with
       the necessity to re-aim the rail gun between  shots.    Fur-
       thermore, the rail gun must supply the 500 MJ kinetic energy
       of  the  homing  head (10 kg; 10 km/s) in about 10 millisec-
       onds, or at a delivery rate of 50 GW.  If the rail gun  were
       30%  efficient,  the power supply to the rail gun would have
       to supply 170 GW in pulsed power.

       SDIO has been  looking  at  homopolar  generators  or  other
       mechanical-electrical  devices  to  provide  such high-power
       pulses--  a  subject on which I worked long ago.(9) In fact,
       SDIO  has  reported  approvingly  to  have  reached   1 km/s
       circumferential speed in flywheels for storing energy, to be
       delivered in this way.

       How  significant an achievement is kinetic energy storage in
       steel (for example) at 1 km/s?   To propel  a  10 kg  homing
       head at 10 km/s would require (at 100% conversion and accel-
       eration  efficiency) all of the kinetic energy in a flywheel
       of mass 1 ton, (assuming that all of the flywheel is  moving
       at  the 1 km/s).   Assuming a 30% efficiency between kinetic
       energy loss of flywheel and kinetic energy  gain  of  homing
       head, and assuming that only 30% of the total kinetic energy
       of  the  flywheel  is  available (15% reduction in speed), a
       flywheel of 11 tons would be needed to propel a single  hom-
       ing  head of mass 10 kg.  Furthermore, to shoot at a rate of
       1 per second, would mean an average power during the engage-
       ment of some 170 MW from  the  prime  source  of  electrical
       power and into and out of the staging flywheel.  In a sense,
       however,  these are details; these are all problems incurred
       by the rail gun-- none of them problems for the mature tech-
       nology of rocket propulsion.   What persuaded  SDIO  leaders
       that the range above 5 km/s "belongs to the rail gun"?  Per-
       haps  Eq. 2  provides  a  hint, since rocket payloads become
       small at speeds high compared with the rocket exhaust veloc-
       ity of 2.5-3 km/s.  How small is shown in the following  Ta-
       ble 1,  in which the first row is the final velocity Vf; the
       second &alpha. is the ratio of final velocity to rocket  ex-
       haust  velocity Ve.   The third row is the mass ratio m from
       the rocket equation,

       | TABLE 1:  For final velocity Vf achieved by rocket  pro- |
       | pulsion                                                  |
       |                                                          |
       |           with exhaust velocity Ve = 3 km/s, the payload |
       | fraction                                                 |
       |                                                          |
       |           is  &mu. and the fraction of fuel total energy |
       | present                                                  |
       |           in the payload kinetic energy is &epsilon..    |
       |                                                          |
       |     Vf     3      6      9      12     15     18 km/s    |
       |                                                          |
       |     &alpha.       1      2      3      4      5      6   |
       |                                                          |
       |     &mu.   37%    13.5%  5.0%   1.83%  0.67%  0.248%     |
       |                                                          |
       |     &epsilon.     59%    62%    47%    30%    17%    9.1 |
       |     %                                                    |
       |                                                          |

       while the fourth row is the energy efficiency in  converting
       to  kinetic  energy of payload the internal energy of a mass
       of propellant equal to the initial mass of the  rocket  less
       the final payload.  Eq. 4 shows the relevant formula,

                  &epsilon. == (K.E.)/(P.E.) = 1/2 MfVf2/1/2 Ve2
                                                    (Mo-Mf)    (4)

       with numerical values tabulated in the fourth row of the Ta-

       It  is doubtful that the rail gun can convert electrical en-
       ergy into kinetic energy of the homing head  with  an  effi-
       ciency  greater  than  30%, and it is likewise doubtful that
       the thermal energy of fuel (or rocket propellant powering  a
       space-based turbine) can be converted into electrical energy
       with  an  efficiency  much above 30%.   Taking the composite
       conversion efficiency (9%) from satellite-based fuel to  the
       kinetic  energy  of  the  homing  head, we see that ordinary
       chemical rockets have far better  conversion  efficiency  at
       homing  head speeds up to 18 km/s, where the rocket converts
       9% of the energy of all its propellant to kinetic energy  of
       a homing head that has a mass only 0.25% that of the initial
       rocket mass.

       Even  if homopolar generators and rail guns weighed and cost
       nothing, the rocket would win the competition below 18 km/s.
       The more one works on rail  guns  (even  successfully),  the
       less effective one's space-based defense.

         The Pop-up Anything.

       In  his (favorable) comments on defense against nuclear war-
       heads carried on strategic ballistic  missiles,  Dr.  Edward
       Teller  has often remarked that "one can't base a defense in
       space, because satellites are costly to put up  and  can  be
       shot  down  in  advance  of  an  attack."(10)  In  fact, the
       Lawrence Livermore National Laboratory  (Dr.  Teller's  home
       base)  has long been working on x-ray lasers to be pumped by
       powerful nuclear explosions, with the purpose of  destroying
       missiles  in  boost  or  post-boost phase; if these nuclear-
       pumped x-ray lasers are not to be based in space,  they  are
       to  be  "popped up" from their safe havens on earth or under
       the oceans.  In April, 1983(11) I showed  that  because  the
       earth  is  round,  very  severe  requirements are put on the
       rocket that carries the x-ray laser warhead  to  its  firing
       position.    The  actual transparency shown 04/13/83 will be
       presented to the conference.  In brief, if the booster  must
       be attacked by the time it reaches its burnout height A, and
       the interceptor is based at range R measured on a great cir-
       cle  along  the earth's surface, and if we assume that there
       is no atmosphere and the interceptor instantly achieves  its
       final  velocity,  the  mass  ratio (ratio of required launch
       mass to x-ray laser  mass)  for  the  interceptor  is  still
       impressively large.  Other critical assumptions in the Table
       are that the booster reaches 7 km/s in a total of 200 s (av-
       erage acceleration 3.5 g), of which 120 s

       | TABLE  2:   For a ground-based directed-energy defensive |
       | weapon to climb high enough to attack  Soviet  ICBMs  in |
       | their boost phase requires large boosters for the defen- |
       | sive  payload  and  would  subject  the payload to large |
       | forces.                                                  |
       |                                  RANGE from ICBM launchpo|
       | nt                                                       |
       |                                     to defensive launcher|
       |                                                          |
       |                                6000    5000    4000    30|
       | 0 nmi                                                    |
       |                                                          |
       | Altitude defensive weapon*     2960    2050    1260     6|
       | 0 nmi                                                    |
       | must reach in 120 sec                                    |
       |                                                          |
       | Mass of defensive missile       2.1 MT   19,000   330    |
       | 4 tons                                                   |
       |  assuming instant burn**                                 |
       |                                                          |
       | Mass of defensive missile      .....    .....   270 KT  4|
       | 0 tons                                                   |
       |  assuming constant acceleration**                        |
       |                                                          |
       | Acceleration required            78      54      33      |
       | 7  g's                                                   |
       |  assuming constant acceleration                          |
       |                                                          |
       | *Assumes 100-nmi clearance  of  the  line-of-sight  from |
       | earth's  surface, and that offensive booster has reached |
       | 200 nmi height.                                          |
       | **Payload mass = 500 kg;  specific impulse = 300 sec.    |
       |                                                          |
       | Source: Author; from Ballistic Missile  Defense,  Edited |
                              _________ _______  ________
       | by A.B. Carter and D. Schwartz (1984).                   |

       is  available for the flight time of the interceptor.  Under
       those circumstances, for a booster  burnout  height  of  300
       miles  (pardon the units), the mass ratio of the interceptor
       is 150,000, so that for an x-ray laser weighing  1 ton,  the
       interceptor  would weigh 150,000 tons at launch.  This large
       mass  ratio  is  determined  by  the   necessity   for   the
       interceptor  to  fly  out a distance P in order to reach the
       horizon plane of the booster at the time of booster burnout;
       by simple geometry, the interceptor would have to  fly  2630
       miles in 120 s, if the interceptor were initially based 6000
       miles from the ICBM launch.

       If one abandoned basing the interceptor on US soil and moved
       it  to  a  submarine at 3000 mile range from the silo launch
       site, the interceptor would have to fly only  650  miles  to
       see  the  booster  at 200-mile altitude burnout, and the re-
       quired mass ratio (for instant-burn interceptors)  would  be
       only 20-- 20 tons for a 1 ton x-ray laser payload.

       Interceptors  of  infinite acceleration are not very practi-
       cal, and they would in any case burn up in going through the
       dense atmosphere even at the 5 mi/s speed of the last  exam-
       ple.      If  one  assumes  constant  acceleration  for  the
       interceptor, then the mass ratio is the square of that shown
       in Table 2, since the final speed of the interceptor is dou-
       ble  the  speed  required  for  instant  burn,  if  the  two
       interceptors  are  to  arrive at their firing point with the
       same delay.  Furthermore, x-ray laser weapons  don't  exist,
       and  one must ask about available countermeasures to the of-
       fense   if   x-ray   lasers   and   their   high-performance
       interceptors  were  produced and deployed.   From the begin-
       ning, it has been obvious  that  reducing  the  duration  of
       boost  phase  would  be a highly effective counter to pop-up
       anything.  For instance, if instead of 120 s  to  reach  its
       firing  point, the pop-up had only 60 s (perhaps from a 90 s
       ICBM boost time, less a 30 s delay for observation, communi-
       cation, and interceptor launch), the mass ratios in the  Ta-
       ble would once again be squared.

       These considerations are summarized in the statement by Cory
       Coll, director SDI systems analysis, Livermore National Lab-
       oratory,  (quoted  by R.J. Smith, SCIENCE, 11/08/85) "In the
       end, the pop-up x-ray laser is simply not feasible against a
       fast-burn booster.  Fast-burn boosters rule out pop-up  any-

         The Problem of Reusable Launchers (Not Necessarily For

       The goal of the US space shuttle program was a capability to
       launch  a  payload  East  out of Cape Canaveral, Florida, of
       65,000 lb maximum, of approximately 300,000 lb put into  or-
       bit  as  shuttle  structure, engines, maneuvering fuel, crew
       and crew support systems, and the like.  Thus only about 20%
       of the orbital mass is payload, and to begin with, the  sys-
       tem  must  be five times cheaper per unit mass into LEO just
       to break even with expendable boosters  launching  the  same

       If  one considers scaling the propulsion system of the shut-
       tle for an expendable launcher, the  "large  external  tank"
       containing  liquid  hydrogen and liquid oxygen would be five
       times smaller (and use five times less hydrogen and oxygen),
       and the expendable boosters would be five times smaller (and
       use five times less solid fuel).  No matter how  many  times
       the  solid-rocket boosters (SRB) are to be reused in the ac-
       tual shuttle, each use expends five times the fuel  required
       to  launch  the same payload on an expendable.  And each use
       incurs costs of returning the rockets to  the  factory,  in-
       specting and refurbishing, and the like.

       But  the deficiencies of the shuttle have not yet been fully
       enumerated.  Another aspect is the much more severe  payload
       loss  due to "earth rotation" in the case of the shuttle.  A
       near-equatorial launch site allows a  greater  payload  into
       LEO  than would be the case from a stationary earth, because
       the eastward velocity of the earth's surface,
         VE(&lambda.) = (40,000/86,400) cos&lambda. km/s

       need not be supplied by rocket propulsion.  This amounts  to
       some 0.4 km/s at Cape Canaveral, Florida.

       Specifically, the satellite speed is given by Eq. 5,

                     (VLEO)2/RE = g,   VLEO = 7.94 km/s.        (5)

       As  a  function of latitude &lambda. and orbital inclination
       &alpha.  the required velocity gain from the  moving  launch
       site is given by

       &Delta.VLEO(&lambda.,&alpha.) = VLEO  - VE(&lambda.) cos((6)

       Most  satellites in LEO are in polar or near-polar orbit, so
       that they can observe the entire surface of the earth as the
       earth turns under the circular orbital track.  For polar or-
       bit, we have &Delta.V = VLEO &approx. 7.94 km/s,

       compared with the &Delta.V required of 7.54 km/s needed  for
       least-energy launch eastward from Cape Canaveral.

       For an expendable booster, this difference of 0.4 km/s means
       an off-load &Delta.M from the payload Mp, so that

       (Mp-&Delta.M)/Mp = e-&Delta.V/Ve.   With &Delta.V = 0.4 km/s
       and Ve = 3 km/s,

       this amounts to &Delta.M/Mp = 0.4/3 = 13%  for  polar  orbit
       with an expendable booster.

       For the shuttle, however, this same fraction of reduction of
       mass  to  orbit  applies  now  not to the payload but to the
       gross or total mass into orbit, and the payload reduction is
       not 13% of 65,000 lb (8400 lb) but  13%  of  300,000 lb,  or
       39,000 lb.   A 13% loss of payload for an expendable booster
       becomes a 60% loss of payload for the shuttle into polar or-

       Indeed, the shuttle normally launches into  orbits  of  very
       low  altitude  above  the surface of the earth.  The shuttle
       suffers severe penalties if it is to carry a payload into  a
       higher  orbit  (hence longer life against atmospheric drag).
       Now that the Soviet Union has  followed  the  United  States
       down  the  mind-altering  path of space shuttles, I quote my
       own  words  broadcast(12)  during  the  first  flight of the
       space-shuttle Columbia:

                 "I feel that there is nothing to be done with  the
                 shuttle that couldn't be done better with expenda-
                 ble  boosters...    The shuttle, like the Concorde
                 aircraft, is a technical marvel  and  an  economic
                 disaster...   a real detriment to our military ca-

       In the current era of glasnost, we have also the comments of
       R.Z. Sagdeev on the Soviet shuttle approach:(13)

                 "  outstanding  technological  achievement...
                 but  it  had  absolutely no scientific value.   It
                 went up; it came down.  My personal view  is  that
                 American  experience  with  the  shuttle indicates
                 that from the point of view  of  cost  efficiency,
                 the  shuttle  is in deep trouble.  It is much sim-
                 pler and cheaper to fly a payload with any kind of
                 expendable vehicle."

         The Myth of the Equatorial Space Station.

       In the United States during the decade of the 1960s, as  the
       Apollo  program  to  put an American on the moon within that
       decade and to bring him back safely was drawing to a  close,
       NASA  was  looking  to  its  next major and popular project.
       NASA wanted a space station, but the costs  were  apparently
       too  high, and it accepted the shuttle program instead.  The
       arguments advanced in support of the space  station  in  the
       1960s  were much the same as they are now, although with ex-
       perience, we now have a substantially  better  understanding
       that,  in  my opinion, should reduce even further our desire
       for such an investment.

       A space station would be a near-earth base  from  which  one
       could  refuel, refurbish, and occasionally provide staff for
       satellites.  Furthermore, one could conduct  scientific  ex-
       periments,  carry out militarily significant activities, and
       the like.  Never mind that even in the 1960s,  these  things
       could  be better done with the remote involvement of men and
       women.  In the 1990s, performance of the very best  individ-
       uals  has improved marginally, but the performance of commu-
       nication and  automated  systems  has  improved  enormously,
       thereby  further tipping the choice toward keeping people on
       the ground.  The role of people in space is left for a later
       section; we now address a &Delta.V myth regarding the  space

       More  recently, Lennard A. Fisk, Associate Administrator for
       Space Science and Applications, NASA, has explained that  in
       the era of the space station, "... a polar-orbiting platform
       associated  with  the  station would be ideal for a proposed
       major mission to study the Earth and its resources."(14)

       For reasons indicated in  the  previous  section  about  the
       shuttle,  the  space  station  elements  are  expected to be
       launched eastward from Cape Canaveral into an orbit the  in-
       clination  of  which  is  thus equal to the latitude of Cape
       Canaveral (about 28 degrees).   Into polar orbit,  the  same
       number  of  shuttle  launches could carry less than half the
       payload.  What, then, is the nature of the "association"  of
       the polar orbiter with the space station?  If the two are at
       similar  altitude,  then  it might be practical to phase the
       satellites in their orbits so that they came close  together
       twice  each  revolution.   But is it practical to go from an
       equatorial platform to a polar platform for servicing, refu-
       eling, or modifications?  Of course, it is  always  possible
       to  supply  a  person  into orbit via an expendable booster.
       The United States did  that  in  the  Mercury,  Gemini,  and
       Apollo  programs.   In this paper, we have paid a lot of at-
       tention to the crucial question of  velocity  gain  and  the
       minimum  mass  ratio  thereby  imposed by rocket propulsion.
       For visiting a polar-orbiting platform directly from  Earth,
       one  would  need  8 km/s velocity gain to go up to the plat-
       form, and about 0.2 km/s to come down, since return from or-
       bit to the Earth can readily be  accomplished  by  firing  a
       small  retro-rocket in order to have the orbit graze the at-
       mosphere about half a revolution ("rev") later.  The  Soviet
       Union's  unmanned  first  shuttle test has now shown what we
       have always known-- that automated and accurate return  from
       orbit  is possible.  Thus ground-based servicing for the po-
       lar orbiter is possible with a total velocity gain  of  some
       8.2 km/s.  How about servicing from the space station?

       Avoiding  irrelevant conceptual complications, we consider a
       space station in pure equatorial orbit, and assess  transfer
       from  that  orbit to a polar orbiting satellite.  To go from
       the 8 km/s eastward velocity of  the  space  station  to  an
       8 km/s  northward  velocity of the polar orbiter can be done
       in various ways, three of which are now considered.  Concep-
       tually, the simplest is to brake the orbital  speed  with  a
       rocket,  and  then to increase it in the northward direction
       (Path A).  This would mean a rocket-induced velocity  change
       of  16 km/s,  and  is obviously far from optimum.  Path B (a
       quarter circle in velocity space) corresponds to maintaining
       the magnitude of the speed at all times, while adding veloc-
       ity perpendicular to the  existing  instantaneous  velocity.
       The  transfer  vehicle  remains  in  orbit, but the velocity
       change required is &pi./2  times  orbit  velocity,  or  some
       12.57 km/s.   Path C (a straight line in velocity space) ob-
       viously involves a velocity change &sqrt.2 times orbital ve-
       locity or about 11.3 km/s.

       If a person is assigned to go from the space station to  the
       polar  orbiter  and  back  again via path C, he or she would
       need provision for a velocity change of 22.6 km/s.   Includ-
       ing  the  launch  to  the  space station to begin with (some
       8 km/s), the velocity gain associated with this caper  would
       be  some  30.6 km/s or a mass ratio of some 27,000, assuming
       an effective exhaust velocity of 3 km/s for the  rocket  en-
       gines  involved.    Considering that the same job could have
       been done from the ground to the polar orbiter and back with
       a velocity gain of 8.2 km/s (and a mass ratio of  15.4),  it
       is, to say the least, not at all clear how the space station
       would be involved with the associated polar orbiter.

         Laser-powered Launch of Satellites.

       Ground-based  lasers  might  be used to launch satellites or
       deep-space probes.  Powerful lasers on the ground would heat
       inert propellant material in the rocket as it rises  through
       the atmosphere and into space.  The propellant might be con-
       tained  in a heating chamber and expelled through a standard
       rocket nozzle, or repeated intense laser pulses could ablate
       (evaporate) it from a flat plate at the base of the rocket.

       To minimize the absorption of laser light  as  it  traversed
       the  atmosphere,  such a system might involve a relay satel-
       lite in geosynchronous orbit and a number of  focusing  mir-
       rors   in   low  earth  orbit,  in  order  to  provide  most
       flexibility for delivering energy to the rocket  powered  by
       the ground-based laser.  It is not the pressure of the light
       itself,  but  the driving of material off the rocket at high
       speed, that would provide recoil momentum to the  body  just
       as in normal rocket propulsion.

       Consider  the  approach  involving  an  ordinary "combustion
       chamber" into which laser light is fed, to heat an  effluent
       material.    Hydrogen gas, provided with an additive for ab-
       sorbing light, would be an efficient propulsion medium,  but
       such  a  system  has  no  element of advantage over ordinary
       rocket propulsion.  For launch of satellites  to  low  earth
       orbit, there can be no energy saving over the normal rocket,
       which achieves near-maximum efficiency of energy utilization
       (some 30% of the propellant energy) in providing kinetic en-
       ergy  of payload.  Providing the energy from the ground does
       little to reduce the mass or cost of  the  rocket,  compared
       with  providing  both  expulsion mass and chemical energy in
       the fuel, so there is no possibility of recovering the  cost
       of the laser system.

       An  approach with more promise is to illuminate a flat plate
       of specially designed ablative material with carefully timed
       pulses of intense laser light.  Successive pulses might dif-
       fer in wavelength so as to continue to deposit energy in the
       blown-off material so that it  can  achieve  blowoff  speeds
       perpendicular  to  the  ablating  plate-- kinetic energy per
       gram blown off-- large compared with the thermal  energy  at
       any  containable temperature.  This approach, however, would
       be useful only for speeds far in  excess  of  satellite  and
       ICBM needs.

       In  the velocity regime that might be used for space defense
       against ballistic missiles, there is  no  potential  benefit
       associated  with laser propulsion.  Nevertheless, supporters
       of such an approach have called  for  funding  related  work
       within the SDIO budget.

       The  deployment of laser-powered launch systems would result
       in a significant (but vulnerable) ABM capability,  not  from
       the  propulsion  of  interceptors but from the potential for
       direct destruction of missile boosters by the intense  laser
       light.  For instance, to launch 10 tons into low-earth orbit
       (8 km/sec  velocity  gain) in 320 seconds (during which time
       the vehicle would have  moved  under  constant  acceleration
       some  1,300  kilometers)  would  require the transfer to the
       payload of some 320 gigajoules of kinetic energy;  that  is,
       the payload would have to gain kinetic energy at the rate of
       1 gigawatt  (GW).  This is the power output of a large civil
       nuclear power station.

       The lasers proposed directly for space  defense  would  have
       power  outputs on the order of 0.1 GW, and not 1.0 GW.  Fur-
       thermore, one can hardly conceive of  a  laser-rocket  effi-
       ciency  much  better  than  50 percent,  and even that would
       require a 2 GW laser source if all the laser light traversed
       the atmosphere without scattering or loss.  If one assumes a
       tenfold loss of laser light in traversing the atmosphere and
       spilling over at the relay mirrors, a laser of  20 GW  would
       be required as a source.  In fact, it would be remarkable to
       obtain a laser efficiency (conversion of electrical power to
       laser  light)  of  30 percent,  which  would require a prime
       electrical power input of  some  70 GW  during  launch,  and
       hence  a laser enormously overpowered even for the space de-
       fense role.

       Such an enormous program would offer no possibility of bene-
       fit for satellite launch, since ordinary rocket fuel  energy
       is converted to satellite kinetic energy at 31 percent effi-

         NON-&DELTA.V MYTHS.

       Of the two remaining myths to be discussed, neither involves
       the  rocket  equation for velocity gain &Delta.V.  The first
       has hardly achieved myth status, since it was  debunked  be-
       fore  it  was  offered, but I discuss it here because it may
       arise again before naive audiences.  The second myth is  the
       very  serious one elevating beyond reality the contributions
       of people in space.

         The Myth of Survivability of Defensive Satellites in "Non-
       Keplerian" Orbits.

       In an exchange between Congressman Les  AuCoin  and  General
       Abrahamson  on pages 612 and 642 of "HAC, DOD Appropriations
       for 1987, Part 5" regarding space mines, General  Abrahamson
       suggests  a  "very interesting kind of concept is a tethered
       satellite ... so long ... that it exceeds the range  of  ef-
       fectiveness  of  a nuclear burst."  Since a nuclear burst is
       likely  to kill satellites at a distance of 100 km,(15) this
       is quite a long tether, indeed.  But this proposal  is  nei-
       ther new nor effective.(16)

            "...  For instance, in principle a satellite could  de-
            part continuously by 100 km from an elliptical orbit by
            attachment via a 200-km-long tether to a similar satel-
            lite-- the two rotating about the center of the tether.
            Two space mines could do the same.

            "Ultimately,  as  the feared effectiveness of defensive
            systems increased,  the  space  mines  would  be  semi-
            autonomous,  so that any attempt by the quarry to disa-
            ble the space mines or to evade them  would  result  in
            the  destruction  of  the  quarry.   This certainly in-
            creases the volatility of space and of the nuclear con-
            frontation in general, but would surely be regarded  as
            preferable  by  either superpower to allowing the other
            side to disarm it by effective space defenses."

       The idea, however, that a powerful nation is  going  to  lie
       down  and play dead while the other side "protects" its sat-
       ellites by increasing their mass and deploying each one on a
       200-km tether is just not persuasive.  Does SDIO  understand
       the  critical  vulnerabilities that they introduce for them-
       selves with these tethers?  For instance, if  we  imagine  a
       pair  of  satellites  each  weighing 1000 kg, separated by a
       200-km tether and rotating once every 16 minutes (1000  sec-
       onds),  each satellite is tugged by 0.36 g, and the force on
       the tether is about 360 kg.   Assuming that the  tether  can
       operate  at  a  stress equal to that in high-strength steel,
       but is only as dense as plastic  (100,000 psi,  and  density
       1.0),  it  would  need a cross-sectional area of 0.05 sq cm,
       and the tether itself would weigh one ton.

       Without having done the experiment, it is difficult  to  say
       exactly, but it is highly likely that a tether under tension
       would  be  severed  by collision with a tether of 1/10th the
       diameter, striking it at orbital speeds.   In  the  predomi-
       nantly  polar  orbits  which  would  be used for space-based
       ballistic missile defense, satellites  are  as  often  going
       south  over  a given point on Earth as they are going north,
       and a reasonable collision speed would be up  to  twice  the
       orbital speed of 8 km/s-- for instance 11 km/s.

       One  might  imagine that the satellites are deployed over an
       orbital altitude band of 500 km.   Imagine  that  the  other
       side deploys some inert smaller satellites (weighing only 1%
       as much, and connected by a tether only 1/10th the diameter)
       but  spinning  at  the same rate.  (This is only an example.
       It will be even easier to defeat this system than  indicated
       here.)  If the tethers were always arranged for maximum vul-
       nerability  (for instance, as the satellite moves forward in
       its path, the tether of  one  satellite  might  be  vertical
       while the tether of the satellite coming the other way might
       be  horizontal),  then  the  pass would be sure to sever the
       tethers if the center of the  second  tether  were  anywhere
       within a 200-km square (40,000 sq km).  If one imagined low-
       altitude equatorial tether cutters, the defensive satellites
       would  cross  the Equator every 45 minutes-- so 36 times per
       day.  The 40,000 km circumference of the Equator, times  the
       500-km  altitude  band  assumed  for  these satellites has a
       total of 20 million sq km, and a  single  200-km-long  anti-
       tether tether would (with most vulnerable orientation) sweep
       out  36 times 40,000 or about 1.44 million sq km per day.  A
       single anti-tether tether would thus destroy a single defen-
       sive satellite pair in about 14 days, on the average.

       In fact, at times the satellite tethers are  oriented  along
       the  line  of flight, and the anti-tether tether is oriented
       in the wrong direction as well, so the collision rate proba-
       bly has to be reduced by  about  a  factor 10  to  obtain  a
       proper  average.  Nevertheless, for the 100 anti-tether sat-
       ellites ("ATS") which could be launched with the same launch
       capability as a single defensive pair, any defensive  satel-
       lite  would last only a day or so.  But the ATS need have no
       smarts at all-- they are a lot cheaper than  real  defensive
       satellites  which  must  be  equipped with sensors, rockets,
       communications, and the like.

       In reality, each "anti-tether tether"  could  simply  be  10
       kilograms  of wire-- 10,000 one-gram bits each 0.25 mm diam-
       eter and 20 m long, with no satellites attached.

       No doubt many throughout  the  world  would  accept  General
       Abrahamson's  claim  that space mines are no problem because
       SDI defensive satellites can  (and  will?)  be  deployed  in
       pairs  at the ends of tethers so long that they exceed twice
       the lethal range of a space-mine nuclear warhead.

         The Mystique of Man in Space.

       The dreams of an individual childhood,  the  dreams  of  our
       species-- of soaring in the air like the birds or roaming in
       space  free of the ever-felt bonds of the earth's pull-- ac-
       count in part for the large US and Soviet manned space  pro-
       grams.    But  there are less innocent causes as well, among
       them the recognition that careers and money are to  be  made
       by  providing people something that appears inherently good,
       without bothering them about the true cost, the cost of dis-
       carded alternatives ("opportunity cost"), and  the  degrada-
       tion of the national ability to make decisions.

       It  was indeed interesting and a major accomplishment in the
       1960s to confirm that the human species can survive  in  the
       zero-g  environment  of space (properly supplied with atmos-
       phere and temperature) and to extend  that  finding  to  un-
       interrupted  stay  of  a year or more, as has now been done.
       But not one person thus far has paid his  or  her  way  into
       space; nor has the overall manned program repaid its cost in
       any  way  but entertainment value on television.  It is easy
       enough to point to moments in which an  astronaut  has  done
       something  useful  or valuable, such as the recovery and re-
       pair of a satellite that has failed  to  boost  itself  into
       GEO,  but  there  is no possibility of eliminating all fail-
       ures, and it is much cheaper to provide  appropriate  backup
       elements   on   satellites   (or  redundant  satellites  and
       launchers) than to maintain a manned  satellite  program  as
       thus far defined.

       Certainly  in near-earth orbit the resupply, repair, and re-
       covery of satellites can be achieved more cheaply  and  more
       reliably  by unmanned vehicles and remote-manned activities.
       Satellites to be returned to earth in the payload bay of the
       shuttle must be designed specifically for  that  portion  of
       their  life cycle, including the re-folding and secure stor-
       age of solar panels.  They could more  readily  be  equipped
       with an ablative heat shield for unmanned reentry to the at-
       mosphere, with remote guidance to a soft landing on a track-
       mounted  sled  or to a parachute landing further softened by
       the vertical retro rockets in use for the past  two  decades
       for air-delivered military equipment.  Furthermore, recovery
       from  LEO  after  normal life of 5-10 years will, one hopes,
       bring back of a satellite of old technology, and there is  a
       very real question whether the progress of technology is not
       such  to make it uneconomic to re-use such an old satellite.
       If one were presented with  a  free  10-year-old  video  re-
       corder, would one really want to upgrade it to modern stand-
       ards, or would it be cheaper to start fresh?

       Of  course,  people  in space would be a necessity for space
       colonies, but space colonies will be a great economic  drain
       on  earth-based  life,  without  any possibility of moving a
       significant fraction (even  1%)  of  people  from  Earth  to
       space.    Arguments that space colonies can prosper and sup-
       port themselves involve an unsupported assumption of 17% an-
       nual growth in productivity, without  any  consideration  of
       political organization and without comparison with putting a
       similar  isolated colony into even the most inhospitable re-
       gions on Earth, such as the oceans or the deserts.

       Another argument for a vigorous manned space program is  the
       necessity  to  "maintain  the  momentum" of the manned space
       program itself.  Why?  The first eight years of manned space
       flight led to the Apollo landing on the moon  and  the  safe
       return of the astronauts to Earth.  No matter how long a hi-
       atus  without  manned space flight, how is it possible (with
       ever advancing general progress of technology) that we would
       not be ready to fly again, and more effectively?   In  fact,
       constant  practice within budget constraints largely results
       in preserving old and diminished  capabilities  rather  than
       the  modern,  effective  space-flight  capability that would
       emerge if we restarted the program when we had a use for it.


       I say "lessons to be learned," because they have not already
       been learned.  The first lesson is that we pay a  very  high
       price  to  maintain  these myths, far beyond the cost of the
       particular program.

       The second lesson is that there is  a  continued,  important
       role  for  scientists.    Neither the Challenger disaster of
       January 1986, nor the Chernobyl disaster of April  1986  re-
       quired deep scientific insight to observe that something had
       gone  wrong.   But in both cases, the hazards existed before
       the disaster, and was reasonably  accessible  to  scientific
       inquiry.    In both cases, in my opinion, the entrenched bu-
       reaucracy prevented the voices of scientists and other know-
       ledgeable critics from being heard, although the problem  of
       cost-ineffectiveness  of  the space shuttle program, and the
       hazard of suppressing the evolution and  continued  procure-
       ment  of  expendable  boosters was far simpler to state than
       was the task of analyzing the hazard of the  combined  phys-
       ical   and  management  deficiencies  in  the  case  of  the
       Chernobyl-type power reactors in the Soviet Union.    Scien-
       tists should vigorously report the truth, and this should be
       welcomed by their colleagues and by society.  Even a program
       that is "merely wasteful" is denying wealth to people and is
       damaging the ability to make proper decisions.

       Returning  to  the  arms race, we note that in many cases it
       takes participation of both sides to become a  real  hazard,
       as  can be seen in interpersonal relations.  As small a mat-
       ter as inadequate calibration or judgment of the  effort  on
       the other side (or "worst-case analysis") can over the years
       and  successive  budget  cycles result in a threatening arms
       race.  This might be avoided if one side  is  vastly  richer
       than  the  other and can afford much "greater" security, but
       if both sides are comparable and look to  compensate  "capa-
       bilities"  and  not  intentions  on the other side, one will
       eventually see, on both sides, vast  military  machines  for
       which  there is no rational reason, which will therefore in-
       spire fear and instability on the other side.

       We have in these myths the danger of jargon and of rhetoric.
       Many honest, loyal people are involved in  the  continuation
       of  these  programs.   In the modern world of persuasion and
       advertising, they are asked to turn  their  talents  to  the
       support  of  the program of their organizations, and they do
       this very well-- with public relations and  lawyerly  skills
       that  must  be  admired, but with results that can be disas-
       trous.  In the SDI program, we now see that the  promise  of
       President  Reagan to "share the technology" of strategic de-
       fense with the Soviet Union has officially become a  commit-
       ment  "to  share  the  fruits  of  technology."    As I have
       commented,(17) "sharing the fruits of technology" can be un-
       derstood  as  the  mutual  occupation of a peaceful world in
       which one side has nothing to fear from the nuclear  weapons
       of  the other side, because of an impenetrable shield, while
       the other side (with useless nuclear weapons) has nothing to
       fear because the protected side has no "reason  to  attack."
       More  simply, in feudal days, both lord and serf "shared the
       fruits of the wealth" of the lord.   The lord did  this  di-
       rectly, and the serf lived whatever kind of life was optimum
       as  directed by the leadership of society.  Human beings owe
       their society honesty and candor, and they  should  be  very
       cautious  before  using their talents to deceive or mislead,
       especially in the service of a program of  their  government
       or society.

       The code of honor of the United States Military Academy for-
       bids  not  only lying but also "quibbling," which is the use
       of words in such a way  that  they  give  a  misleading  im-
       pression  of assurance, threat, etc.  If we all perceive the
       reality, then we can all turn  our  attention  to  improving
       this  world.   At present, the myths of space technology in-
       hibit our putting an end to the extension of the  arms  race
       into  space, and they deny modern societies the full produc-
       tive civil and military (non-weapon) uses of space.

       1   Created to pursue President Reagan's goal of  a  techno-
           logical  program  to render nuclear weapons impotent and
           obsolete, as stated in his speech  of  March  23,  1983.
           The  SDI  was  officially formed one year later, and Lt.
           Gen. James A.  Abrahamson selected to head it.
       2   As stated in National Security Decision  Directive  172,
           discussed  in  The  Strategic Defense Initiative, US De-
                          ___  _________ _______ ___________
           partment of State Special  Report  No. 129,  June  1985,
           p. 4.
       3   Thus far untested in space is propulsion within the  in-
           ner solar system by the momentum of sunlight itself, re-
           flected  from  vast  "solar  sails".    See R.L. Garwin,
           "Solar Sailing-- A Practical Method of Propulsion Within
           the Solar  System,"  Jet  Propulsion,  March  1958,  28,
                                ___  ___________
           No. 3, pp. 188-190.  Also, L. Friedman, Starsailing: So-
                                                   ____________ ___
           lar  Sails  and  Interstellar Travel, John Wiley & Sons,
           ___  _____  ___  ____________ _______
           Inc, (1988).
       4   Spacecraft  Propulsion  Systems--  What They Are and How
           They   Work,"   by   Robert   H.   Frisbee,   Foundation
           Astronautics  Notebook-6,  World  Space Foundation, Jan-
           ____________  ___________
           July 1983.
       5   One cal = 4.186 joule.
       6   Speech  of  Lt. Gen. James A. Abrahamson to the National
           Press Club, November 15, 1988.
       7   From R.L. Garwin, "Defensive and  Offensive  Weapons  in
           Space,  and  Civilian  Space Technologies," Presented at
           the Third  International  Conference  of  the  USPID  on
           "Technology,  the  Arms  Race,  and  Arms  Control,"  at
           Castiglioncello, September 26, 1987 (to be published).
       8   Chris Cunningham, Tom Morgan, and Phil Duffy, 'Near-Term
           Ballistic  Missile Defenses' Strategic Defensive Systems
           Studies Group of the Lawrence Livermore National Labora-
           tory, (1987).
       9   "The Production of Axially  Symmetric  Magnetic  Fields,
           and   New   Power   Sources   for  Large  Betatrons  and
           Synchrotons," R.L.Garwin, (Thesis for the B.S. in  Phys-
           ics at Case Institute of Technology.)  May 15, 1947.
       10  Quoted, for example, in National Geographic, March 1984,
                                   ________ ___________
           page 363.
       11  Arms Control Symposium panelists:  H.A. Bethe,  D. Kerr,
           R.L. Garwin,  E. Teller,  April 13, 1983, Los Alamos Na-
           tional Laboratory (40th Anniversary commemoration)
       12  MacNeil-Lehrer Report, "The Space Shuttle and  Defense,"
           April 13, 1981.
       13  Quoted by J.N. Wilford in The New York Times of November
                                     ___ ___ ____ _____
           22, 1988.
       14  Quoted in The New York Times of May 3, 1988.
                     ___ ___ ____ _____
       15  The SDI goal (paper supplied by Major Simon  P.  Worden,
           Special Assistant to the Director SDIO, re Near-term SDI
           Architecture Study, 1986) is to harden satellites to re-
           sist a 1 megaton nuclear burst at 100 km.
       16  For  instance,  H.A.  Bethe  and I wrote the above inset
           section for our chapter  (draft  of  11/19/84)  for  the
           "Weapons  in Space" book of the American Academy of Arts
           and Sciences, published 1985.
       17  Symposium on "New Defense Technologies and the Strategic
           Balance," Southern Methodist University, Dallas,  Texas,
           September 1986.