wall street makes a call to action and how to move an asteroid

This article was printed by the wall street journal
and I thought it may be of interest to this group.

While most of it is about Mars, towards the end it
talks about asteroid protection. This has been a
topic I have been giving a heck of a lot of thought to
recently.

Often times we have looked at the prime motivator for
boot-strapping (to steal tangoman's concept) our
development to be SPS. But as has been discussed in
the past, SPS has a rather small rallying cry.
Asteroid threats however are very real, and heck it
even has many movies about it. (how many movies show
SPS?). Its voice is louder and perhaps this is the
best rally flag to gather under, especially in terms
of opening up the new frontier.

Lets think a bit on this for a bit. Just how do we
move an asteroid (i had to actually calculate all this
for a class recently). Easy, just strap an engine to
it and push it. Lets start with a 500 meter asteroid
with a mass of 1.3 x 10^11 kg (thats only a density
of 2 gm/cm^3). Lets also say its moving at 35 km/s
and by some stroke of luck, we detect that its ging to
hit us in 3000 days (a big leap that our current
asteroid finders cannot currently make).

Now when this asteroid hits us at the current speed,
we are talking about an explosion of 19,100 Megatons
of TNT. Not a number to lauhg at as that is about 1
million times the energy of the hiroshima bomb.

Now in order to move this asteroid 100,000 km sideways
before it impacts us in order to save our sorry butts,
we have to apply a delta v of approximately 0.39 m/s.
Lets say we use a relatively efficient LH2/LOX engine
iwth an Isp of 460 s. To produce the amount of thrust
needed, we would need to 11,200 metric tons of fuel!

Lets say we were able to ferry fuel to orbit for only
$4,300/kg. This would mean it would take $48.2
billion! While this would make lockmart and boeing
estatic, we are talking a hefty bit of change.

Even if we were to use a nuclear bombs to move it
(assume an Isp of 1 million), it would still take
5,150 kg bomb at 100% efficiency to move the asteroid!

The only other alternative is the use in situ
resources. Assuming the asteroid was a CM2 or some
other carbonaceous chondrite with water, we could land
a processing facility on there to make the required
fuel. Assuming that the asteroid was 10% water, and
our propcessing plant was able to process about 240
tons of material per day, we could produce enough fuel
to move the asteroid safely away in 500 days, thus
saving all of our lives.

Should this be the argument we are looking at to
finally get something going? Currently, we don't have
the capabilities to create such a facility or even to
detect the oncoming asteroid threat. Fulfilling this
plan to me makes a heck of a lot more sense than
arguing over whether or not SPS is needed. And it
certainly makes an easier sale.

Just my thoughts for the day after reading the wall
street article and listening to Paul and Tangoman go
back and forth.

Ryan Z

The complete text of Begley's column appears below.

Space Program Needs More Little Green Men And Less
Green Cheese
By Sharon Begley
943 words
12 December 2003
The Wall Street Journal

PEERING INTO the heavens on a starry night, you can't
help but be
struck by the single most obvious trait of that
"depthless spatter"
(as John Updike called it in a recent poem): It does
not lack for
destinations.

But you wouldn't know that from the rumblings out of
Washington. It
has been 10 months since the tragic loss of the space
shuttle
Columbia, and four months since the Accident
Investigation Board
called for a national debate on U.S. space goals.
There hasn't been
much of one; instead, officials have been meeting
behind closed doors
as part of an interagency review of space policy,
asking how, or even
whether, the U.S. should reach for missions more
glorious than joy
rides that go around in circles (via the space shuttle
and
International Space Station).

What's now emerging is more than dismaying. It looks
like President
Bush will propose little more than a riff on President
Kennedy's
vision of 42 years ago: Destination Moon.

Next week marks the 100th anniversary of the first
powered flight in a
heavier-than-air machine, Orville Wright's 12-second
flight over the
dunes of the Outer Banks, with brother Wilbur running
alongside. With
that derring-do in mind, surely we can reach higher
than lunar
repeats. Measured by its value to science or to the
soul, or by how
it can inspire discovery or the imagination, the moon
might as well
be green cheese.

SURE, ITS LUSTER grew a bit in October, when China
flew its first
astronaut into space and Chinese officials spoke of
hopes for lunar
bases. There's nothing like the interest of other
travelers to make a
destination hot. And indeed, moon missions might shed
light on how
the inner planets formed. But when it comes to moving
the national
spirit, aeronautical engineer Robert Zubrin, president
of the Mars
Society, has it right. "How can you inspire young
people with
something that repeats what their grandparents did?"
he asks.

Not to take anything away from the science of planet
formation, but it
doesn't hold a candle to collecting clues about
whether we are alone
in the universe and, if not, whether our kind of
biology is the only
way to build living things. For that, it's Destination
Mars.

There, astronauts could comb the surface for fossils
and drill down to
groundwater to search for extant life. Mars has or had
the right
chemicals,liquid water, a temperate climate, minerals
and enough time
for life to get going. If turning chemistry into
biology is harder
than that, the universe is likelier to be lonelier
than many suspect.
But if there is or was life on Mars, we would learn
whether the
carbon-and-DNA-based variety is the only recipe or, as
Dr. Zubrin
puts it, "whether we are simply one esoteric example
of a far vaster
and more interesting tapestry."

Finding the answer need not break the bank. Since
1989, Dr. Zubrin
has been refining his "Mars Direct" proposal, which
would let
astronauts reach the red planet on the cheap and stay
for 1.5 years
by living off the land and atmosphere. Mars has
copious quantities of
carbon, nitrogen, hydrogen and oxygen, the stuff of
food, water and,
most important, rocket fuel. A chemical-processing
unit, delivered by
an unmanned craft months before astronauts set off,
could manufacture
fuel on Mars for the return home. Not having to haul
propellant
allows payload and other savings that slash the cost
of a Mars
mission. It wouldn't be the $400 billion estimate that
NASA gave the first President Bush, but less than $30
billion, says
Dr. Zubrin

ANOTHER WORTHY PROJECT would target the threat of
asteroids. The Jet
Propulsion Lab lists 47 of these space rocks whose
orbits have "a
nonzero probability" of sending them crashing into our
defenseless
planet in the next 100 years, killing millions. In a
private,
grassroots effort called Project B612 -- named for the
tiny asteroid
on which "The Little Prince" in Antoine de
Saint-Exupery's novel
lands -- engineers, physicists and others are looking
for ways to
improve our odds.

"The main goal would be to change the orbit of an
asteroid
sufficiently to avoid an impact with Earth," says
astrophysicist Piet
Hut of the Institute of Advanced Study, Princeton,
N.J., co-founder
of B612.

The technology to send a spacecraft to a 100-yard
diameter asteroid,
then nudge it off course, is straightforward.
Astronauts (the job is
too complex for robots) would set up a device called a
mass driver
that throws rocks off the asteroid, propelling it in
the opposite
direction. "When we discover an asteroid with our name
on it, so to
speak, we will be prepared," says Dr. Hut.

Wherever we go, the point is to make the manned space
program
destination-driven rather than technology-driven
(whether we should
have a manned program at all is a debate for another
day). That's not
how NASA does it. Instead, planners settle on a flight
technology and
then look for where it can take us. Right now,
influential officials
are pushing nuclear-electric propulsion. Building a
space platform at
the orbital point called L1, where the gravity of
Earth and the moon
precisely balance, turns out to be one way to test it,
launching
nuclear-propelled spacecraft to the moon.

Nuclear may have a role to play, but let's find out by
first choosing
where we want to go.