DTIC ADA529673: Planetary Defense. Department of Defense Cost for the Detection, Exploration, and Rendezvous Mission of Near-Earth Objects

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by  Defense Technical Information Center

PLANETARY DEFENSE
Department of Defense Cost for the
Detection, Exploration, and Rendezvous
Mission of Near-Earth Objects
LT COL ROSARIO NICI, USAF
1ST LT DOUGLAS KAUPA, USAF
EARTH IS ON a collis ion Crat ers on Earth do not last long due to
course! Microm et eori tes weather and geologic al erosion. Geolog ists
regul arly streak into the at­ have, however, pinpointed some very old cra­
mosp here causing little more ters. A NEO slammed into Quebec 214 mil-
than a fiery flash. However, lion years ago, leaving a 100-kilometer-w ide
larger near-Earth objects scar known as the Manicouag an Crater (fig.
(NEO) can have a more dra­ 1). In central Austral ia 70 million years later,
matic effect on the Earth. Recently scien tists ano ther NEO created a 22-kilometer-d iameter
pres ented evidence in which an astero id, at crat er (fig. 2). Evidence suggests the demise
least a mile in diamet er, hit the ocean 35 mil- of the dino saurs occurred 65 million years
lion years ago southeast of what is now Wash­ ago with the impact of an astero id 10 kilome­
ingt on, D.C., shaping the Chesapeake Bay.1 ters in diamet er. Named the K/T event, the as­
Tod ay such an impact would cause devast a­ tero id struck with the force of 100 million
tion on a global scale. The mitigat ion of such megat ons of TNT, creati ng a crater 180 kilo-
a natural disast er necess it ates an intern at ional met ers wide off the coast of the Yucat an Pen-
planet ary defense. This artic le provides a back- ins ula in Mexico. Even North America was
ground of the threat of NEO-Earth impacts visi ted by a NEO nearly 50,000 years ago,
and addresses planetary defense taskings and crea ti ng Arizon a’s Meteor Crater (fig. 3).2
Dep artm ent of Defense (DOD) costs for the
next 20 years as part of an intern at ional effort
to detect and learn more about NEOs.
Background
A NEO is a natural object (aster oid, short-
or long-period comet, or a meteor stream) of
any size that will come close to or cross
Earth’s orbit, or even impact the Earth. In
the past 15 years, research on NEOs has dra­
matic ally increased as astronom ers and ge­
olog ists real ize the Earth is nothing more
than a billiard ball in a cosmic pool game.
Our world was struck in the past and will be
struck in the future. Figu re 1. Manicoua gan Cra ter, Que bec
94
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1. REPORT DATE 3. DATES COVERED
1997 2. REPORT TYPE 00-00-1997 to 00-00-1997
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
Planetary Defense. Department of Defense Cost for the Detection,
5b. GRANT NUMBER
Exploration, and Rendezvous Mission of Near-Earth Objects
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
Air and Space Power Journal,155 N. Twining Street,Maxwell REPORT NUMBER
AFB,AL,36112-6026
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11. SPONSOR/MONITOR’S REPORT
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13. SUPPLEMENTARY NOTES
14. ABSTRACT

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PLANETARY DEFENSE 95
Fig ure 2. Wolf Creek Cra ter, Aus tra lia Figu re 3. Meteor Crater in Arizona (Reprinted with
perm iss ion of Univers ity of Arizona Press from
Tom Gehrels, ed., Haza rds Due to Comets and As­
Today there are 140 known impact sites on tero ids [Tucson: Univers ity of Arizona Press, 1994],
the Earth with many hundreds awaiting verifi­ 430.)
cat ion.3 Figure 4 illust rates the major sites.
sta tions may be impacted, degradi ng their
Earth, however, is not the only planet tor­
so lar arrays or damagi ng opti cal sensors.5
mented by orbital debris. In July 1994, Jupi­
Some NEOs nearly reach the Earth’s sur -
ter was struck by Comet Shoemaker-Levy 9.
face. From 1975 to 1992, nuclear detonat ion
The comet passed too close to the gas giant,
de tect ing satel lites recorded 136 atmos pheric
break ing apart due to the immense gravity
and then scarring the planet in several loca­
tions shown in figure 5. If even one of the
kilometer- wide fragments had hit the Earth,
the result would have been catastrophic,4 as
shown by the computer model in figure 6.
Met eor streams occur when the Earth
passes through the orbital path of debris left
beh ind by comets. The debris can range in
size from a centim et er to a millim et er in di­
amet er. Though these streams pose no threat
to humans on the surface, satell ites and space
Figu re 4. 140 Earth Impact Sites (Reprinted with
perm iss ion of Univers ity of Arizona Press from Tom
Geh rels, ed., Haza rds Due to Comets and Aster oids
[Tuc son: Univers ity of Arizona Press, 1994], 430.)
Figu re 5. Impact Scars on Jupi ter
96 AIRPOWER JOURNAL SUMMER 1997
In 1989, astronom ers discove red an aster­
oid labeled 1989FC after its closest approach
to Earth. This illust rates a disturb ing fact.
Cur rently only astronom ers on shoestring,
acad emic budgets are trying to locate and
track NEOs, making estim ates of NEO popu­
la tions very imprec ise. Through the end of
1992, 163 NEOs had been detected and cata­
logued, repre sent ing only 5 percent of the
es ti mated 2,000 to 5,000 NEOs larger than
one kilomet er.11 Scien tists believe a Tun­
guska event will occur every century and a
kilo ton (K/T) event every 25–26 million
years based on the density of impact craters
on the moon.12
Il lus trated in figure 8 is the equivalent
yield in megatons of TNT based on a NEO
with a density of 3 grams/centi me ters (CM3)
and a veloc ity of 20 kilomet ers per second
(km/sec). The shaded area to the left repre­
Figu re 6. Simulat ion of Shoemaker-Levy 9’s pro­ sents the NEO size that will burn up or ex­
jected impact on Earth plode in the atmosp here, though blast
ef fects like Tunguska still could produce
dama ge to the surface. Near the one-
blasts in the megatons-of-T NT range.6 NEOs
kilometer size, NEOs could produce global
can also cause damage to the Earth without
reach ing the surface.7 In 1908, an astero id or con se quences, though there is some uncer­
tainty in the threshold size required as
comet exploded in the atmosp here near Tun­
shown in the dashed verti cal lines.
guska, Sibe ria. Though no crater formed, the
shock wave from the explod ing body devas­ Global disas ters will result if a large
tated 2,000 square kilomet ers of forest.8 If (1-km) NEO impacts the Earth, perhaps kill­
this NEO had reent ered a few hours later, it ing as much as 25 percent of the human
could have destroyed Moscow with a force popu la tion.13 This is largely due to the indi­
one thousand times greater than the Hi­ rect effect of the impact. A land impact pro­
roshima and Nagasaki atomic detonat ions.9 duces fires and earthquakes, while an ocean
In 1992, a brilliant astero id streaked im pact produces tsunam is measur ing several
through the night sky in Peekskill, New hund red meters in height, and perhaps even
York, during several high school football hyper canes, which are runaway hurri canes
games. This event was caught on a camcor­ that inject large amounts of sea water and
der at one of the games, and the astero id aero sols into the atmosp here, causing major
dama ged a car.10 The Tunguska blast area is global climate changes.14 Both will have
twice as big as New York City and three blast ef fects flatten ing nearby structures
times as large as Washing ton, D.C. with the possi bil ity of a global winter
Lucki ly, not all NEO “near hits” cause emerg ing. Global winters are when large
dama ge, but they do illus trate the fact the amounts of ash and dust enter the atmos­
Earth is not immune to their destruct ive ef­ phere, blocking sunlight from reaching
fects. Recorded on a videocame ra in 1972, an pho to syn the siz ing plants. Crops will die
ast ero id grazed Earth’s atmosp here near and world starva tion may result. Also,
Wyom ing’s Grand Teton Mountains and world wide tempera tures would plummet
skipped back out into space (fig. 7). for months, perhaps years.15
PLANETARY DEFENSE 97
Figu re 7. An as ter oid skips through the at mos phere, only one of many “near hits” re corded.
Figu re 8. Avera ge Impact Inter val Versus Size (Reprinted with permiss ion of Nat ure Magaz ine from Clark R.
Chapm an and David C. Morris on, “Impacts on the Earth by Aster oids and Comets: Assessi ng the Hazard,”
Nat ure 367 [6 January 1994]: 37.)
98 AIRPOWER JOURNAL SUMMER 1997
Figu re 9. Mass Extinct ions in Geologic al Record (Reprinted with permiss ion of Plenum Press from C.R.
Chapm an and David C. Morris on, Cosm ic Catast rop hes [New York: Plenum Press, 1989])
Sci en tists have compared mass extinc­
years per global devas tat ing impact, as
tions with major impact craters found on
shown by the horizont al line in figure 10.
Earth and discove red a striking compari son
The probabil ity of a strike in any one year is
as seen in figure 9.16 The K/T event could
1 in 500,000 assumi ng the strikes are com­
have begun the demise of the dino saur era.
pletely at random. Assumi ng 25 percent of
The Manicoua gan Crater in Quebec may
the world’s popula tion could die as a result,
have also helped to end the Trias sic Era by
the risk of death is 1 in 4. Thus, in any one
throwi ng tons of sky-darkening dust into
year per person, the risk of death is approxi­
the air.17
mately 1 in 2,000,000. Over a 75-year life-
If a NEO impacted the Earth today, what
time, the risk is nearly one in 25,000.18
would the estim ates of fatali ties be? Should
Please real ize that the probabil ity of a NEO
we even be concerned? Figure 10 portrays
im pact ing the Earth and causing global dis­
proj ected fatali ties per event. The dash line
as ters is very slim, yet the conseq uences if
repr es ents an ocean impact while the solid
one did impact would leave us with this esti­
line portrays a land impact.
mated risk of death. Furtherm ore, you are
In figure 10, we see the curved line repre­
probab ly wonder ing when the last person
sent ing increased fatali ties with increased
was killed by a NEO. Refer ring back to the
NEO size, yet the time scale on the left indi­
Tung uska blast, the expe di tion that re-
cates longer times between larger NEO aster­
searched the blast found trees, reindeer,
oid diamet ers. In other words, small NEOs
teepees, and nomadic arti facts partly incin­
near 50 meters in diame ter impact the Earth
era ted.19 It is still unknown if anyone did
much more frequently than larger ones.
die.
Howe ver, small NEOs could produce another
Tung uska blast. Therefore, one needs to un­ By now you are thinking we’re predict ing
ders tand the probabil ity of death by any size that the sky is falling. We are not trying to
NEO. The relative probabil ity of death by an scare the reader into spending billions of
ast ero id impact is shown in table 1. dol lars to save the Earth. Rather, we ask for
How does one arrive at a number of 1 in money to be spent wisely on assessi ng the
25,000? Scien tists estim ate there are 500,000 threat, learning more about NEOs, and
PLANETARY DEFENSE 99
Figu re 10. Estim ated Fa tali ties Per Event (Re printed with per mis sion of Nat ure Magazine from Chap man and
Morr is on, “Impacts on the Earth by Astero ids and Comets: Assessi ng the Hazard,” Nat ure 367 [6 January
1994]: 37).
track ing and catalogui ng NEOs. No NEO is armed forces, under the hier ar chy of inter-
curr ently predicted to hit the Earth. Yet ests, for cases of strict humani tar ian con-
somed ay there will be one, as the prob abil- cern.21 Thus, respondi ng to the NEO threat
ity is finite. So who will take a leading role? could be seen to fall under this policy.
The US govern ment, through the DOD, is In the past few years, several differ ent or­
obl ig ated to protect the lives and safety of ganiz at ions in addi tion to DOD began to as-
its citizens.20 Further, the US may use its sess the NEO threat. Astronom ers working at
Ta ble 1

Prob abil ity of Death by an Aster oid

Source : “Im pacts on the Earth by As ter oids and Com ets: As sess ing the Haz ard,” Na ture 367 (6 Janu ary 1994): 39
100 AIRPOWER JOURNAL SUMMER 1997
coll eges have discove red NEOs by several The military has also written about the
metho ds, such as by using telescopes NEO threat. Air Univer si ty’s Spacecast 2020
equipped with cameras to photog raph small re ported on the Air Force’s future and
sec tions of the sky at two differ ent times looked at the NEO threat in “Prepar ing for
nearly an hour apart. The astronom ers then Plane tary Defense.”28 Research was con­
com pare the two photos to observe if any ducted at Air Command and Staff College on
smudge or streaks occurred, thus repres ent­ the same topic.29 The chief of staff of the Air
ing a NEO passing by the Earth. However, it Force tasked Air Force Space Command to
is very tedi ous and time consumi ng to peer acc omp lish a mission area assess ment for
at photo graphs with a micros cope looking de fense of Planet Earth, which should be
for such movement. Furtherm ore, if a streak fini shed in fiscal year 1997.30 Thus, to date
does appear, the astronom ers must first there has been some atten tion given to the
check to see if the streak is not a satel lite fly­ NEO threat. However, the authors believe in
ing overhead or a known astero id or comet. or der to accur ately assess the threat, we need
Ano ther method is to use charge-coupled de- to follow several taskings as elaborated in
vices (CCD) detec tor telescopes.22 This the next section.
method utilizes comput ers to analyze elec­
tronic photog raphs for any streaks that oc­
cur that are not previ ously known, such as
Taskings
sate ll ites or NEOs that have not already been
det ected. The CCD method is much quicker, A planetary defense should include every-
though more expen sive. Altog ether, this is thing that could mitigate a NEO-Earth colli­
only a limited search due to the astrono­ sion. What does one need to know or do
mers’ restricted academic budgets. be fore one can mitigate the damagi ng ef­
In 1990, the American Insti tute of Aero­ fects of a NEO colli sion with the Earth?
nau tics and Astro nau tics (AIAA) issued a po­ Should any of these tasks be accomp lished
si tion paper concerni ng the threat of NEOs conc urr ently? The followi ng list of tasks an­
af ter Apollo astero id 1989FC made the clos­ swers the previ ous two questions.
est approach to the Earth ever detected.23
Stimu lated by this AIAA paper, Congress rec­ Co or di na tion is required to system ati cally
og nized the impact hazard of NEOs and in cover the sky. Several astronom ers from
1991 asked the National Aeronau tics and around the world are surveyi ng the sky, al­
Space Admin istra tion (NASA) to convene a though not in a joint effort. Who will do
de tec tion and inter cep tion workshop. The conf irm at ions and follow-up orbit deter mi­
Subc omm itt ee on Space of the Commit tee nat ion? Can we use the Air Force’s tracking
on Science, Space, and Technolo gy, US syst ems to help detect NEOs?
House of Repres ent at ives, received the sum- De tec tion is required. What should be the
mar ies and held hearings on the threat of lim it ing NEO size detected? How fast should
large Earth-orbit-c rossing aster oids on 24 this occur, within 10 or 20 years? The re-
March 1993.24 Ironically, Shoemaker-Levy 9 quirem ent for timely complet ion of detec­
was discove red about this time. Due to the tion affects the deci sion concern ing sky
im pend ing impact on Jupit er, Congress di­ cove ra ge versus limit ing NEO size and mag­
rected NASA to develop a program and a ni tude. What are the sources of NEOs?
budget estim ate for catalog ing NEOs in 10 Should we detect possib le NEOs, ones that
years.25 NASA’s report encoura ges collabor a­ are currently not near Earth’s orbit but that
tion of the inter na tional commu nity and might become ones? Furtherm ore, how of -
the US Air Force.26 However, Congress only ten should we recheck previ ously scanned
asked NASA to give a cost estim ate, and cur­ ar eas?
rently NASA has no plans to spend new Sci ence covers the mater ial charact eriz a­
money on tracking NEOs.27 tion of the object. What does one need to
PLANETARY DEFENSE 101
Cost
Cur rently planetary defense is not item­
ized in the DOD budget. As with any organi­
za tion, priori ties set the budget. The
app reh ens ion from those not in DOD may
be that any planetary defense could be just
an other excuse for an arms race since the
cold war is over. The real ity from the con­
gres sional perspec tive is that the money for
any efforts specifi cally itemized for plane­
tary defense should come out of DOD’s cur-
rent budget.31
Fig ure 11. Ex plo ra tion of a NEO in the Fu ture Given that the funding is from DOD, sup-
port should be given to those academic re-
search programs that are currently
know about the object in order to mitigate cond ucti ng NEO detec tion, research, and
any damage effects? Can one simulate NEO tech nol ogy develo pm ent and to the Air
com po si tion on Earth and “test” these Force Space Command, which has spent
NEOs? Can we deflect the orbital paths of over $100 million on the technol ogy to im­
NEOs or is destroy ing NEOs and sufferi ng prove the current space surveill ance mission
the remnants impacti ng the Earth the only of the ground based electrical-optical deep
op tion? space system (GEODSS). Space Command’s
Exp lor at ion of NEOs may be a means to rel entl ess efforts of quality and continu ous
com bine the require ment to rendez vous imp rovem ent should be lauded. Not only is
with a NEO for scien tific study while provid­ there an improvem ent in the accu racy of de­
ing the orbital dynam ics know-how for de­ tect ing man-made debris in Earth orbit, but
struct ion or deflec tion. Missions to NEOs also the enhanced tracking of NEOs for a
will prove helpful in planetary defense. plane tary defense is now feasib le. Clearly,
the humani tar ian search for NEOs would be
De struc tion and Deflec tion may be the
a hallmark for efforts to transform military
only ways to prevent damage to the Earth.
as sets into civil ian endeavo rs. Furtherm ore,
Op era tion concepts and options should be
cur rent improvem ents in the GEODSS can
planned and practiced before they are re­
be utilized to improve envir onm ent,
quired to be used to avoid a catast rop he.
weather, and remote sensing, as well as to
Har vest ing is a spin-off of deflec tion. crea te smaller, faster, more intel li gent hard-
Would Earth be lucky if an NEO was ap ­ ware. However, tracking NEOs is not the
proach ing? Could a NEO be “captured” into only solu tion for protec tion. We need to
Earth orbit and then mined to provide re- learn more about NEOs and be prepared to
sources in space? avoid a future colli sion.
Warni ng of the “Big One” is only good if Over the next 20 years, NEO detec tion,
the outcome (global devast at ion) is avoid- exp lor at ion, and rendezv ous missions need
able. Warning of “small” NEOs may save to take place. In a recent Air Command and
countl ess lives and prevent destruct ion due Staff College study, Larry D. Bell and others
to tsuna mis, forest fires, and earthquakes. pro vided an excell ent in-depth look at
Also, warning to prepare for a meteor search systems, their advant ages and disad­
stream may save valuable space assets. vant ages, a system archi tec ture, and cost.32
102 AIRPOWER JOURNAL SUMMER 1997
Figu re 12. Projected Cost for a Potent ial Plane tary De fense Ef fort
De tec tion includes searching for NEOs, quire the interc ept or to orbit the target
maint aini ng a NEO catalog, esti mat ing NEO. The bottom line is that the estim ated
popu la tions of NEOs, and recurr ing opera­ cost for a planetary defense is near $14 mil-
tions and support. Explor at ion consists of lion per year for detec tion, $23 million per
det erm ini ng the NEO origins, under stand ing year for explo ra tion, and $75 million per
how their orbits change due to the planets year for rendezv ous missions avera ged over
or collis ions, and resolvi ng the compos it ion the next 20 years. Figure 12 reflects the
and density of NEOs. Are they solid or rub­ breakd own of the budget each year if we be-
ble objects orbit ing together? Flybys or gin today. These estim ated costs were final­
ground-b ased research will be the van- ized with comments from Mr Nick
guards. Missions like Galileo, Clementine 1 Fuhrm an, science advi sor to the Committ ee
and 2, NASA’s near-Earth astero id rendez­ on Science, US House of Repre sen ta tives,
vous (NEAR) system, and use of the Arecibo and Dr. Bill Tedes chi of the Sandia National
and Goldstone radar systems will increase Labo ra tory.
our knowledge of NEOs. Finally, rendezv ous A limited mitigat ion system that would
miss ions practice the meeting of NEOs be­ cost approxim ately $1 billion over three
yond the Earth’s orbit, testing methods to years is not included above.33 A differe nt es­
de flect or destroy an NEO. These are the tim ate sets costs at $120 to $150 million per
prac tice, small-scale mitiga tion missions in year for two mitigat ion missions to either
case we need to perturb or destroy a NEO de stroy or deflect non-Earth impacti ng
months or even years before an Earth colli­ NEOs over a 10-year period.34 The United
sion occurs. The science missions may re- States will perhaps need an impact scare to
quire observ at ions from Earth or flybys of push Congress to approve a mitigat ion pro-
the target, whereas rendezv ous missions re- gram because any system with the capa bil ity