Mission to Mars (15 page)

That chapter in the space exploration history books is closed. Today, I call for a unified international effort to explore and utilize the moon, a partnership that involves commercial enterprise and other nations building upon Apollo.

For the United States, other finish lines await.

Asteroids may be rich in resources but may also threaten Earth
.

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Illustration Credit 4.11
)

There is an important question we all need to face in the immediate future—and that is sustainability. Earth’s population is now at over seven billion people. In terms of consumption, the resources obtainable on our globe to provide for that quickly growing number of humans are untenable. At the same time, while we do our utmost to sustain our global security, there are questions about the environmental distress humanity is placing on our planet’s ecosphere.

Do we compete for the diminishing resources remaining on Earth—an inward, closed system? Or, alternatively, do we work together in utilizing the limitless resources and opportunities available in outer space—an open and expansive system?

Well, to me, the best option is obvious.

There is history behind events that have menaced life on Earth. It is also inescapable that there are new threats we cannot predict. One clear step we can embark on is to enhance the survivability of our species. We can explore and settle new worlds, establishing fresh footholds and new beginnings. This is made possible by evoking bit by bit movement, once again as exemplified by the Mercury, Gemini, and Apollo progression of programs, letting us transit farther into space and accumulate the know-how to land humans on Mars.

Mapping the belt of asteroids or near-Earth objects (NEOs)

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Illustration Credit 5.1
)

That is precisely what is behind my Unified Space Vision, which preserves U.S. leadership in space exploration and human spaceflight. The USV brings in concert exploration, science, development, commerce, and security elements. That security component I view as one that signifies
both
U.S. defense and a cosmic counterpart: planetary defense of Earth from near-Earth objects, or NEOs.

Planetary defense of home planet Earth means getting to know the enemy—and I am not talking about down-to-earth squabbles between nations. I’m highlighting here a celestial fear factor stemming from asteroids and comets.

NEOs have been nudged by the gravitational attraction of nearby planets into orbits that allow them to enter Earth’s solar system neighborhood. We should learn more about these extraterrestrial wanderers in both scientific and practical terms. I believe my USV essentials of exploration, science, development, commerce, and security fit well with NEOs.

In recasting the U.S. space exploration program in April 2010, President Obama called upon NASA, early in the next decade, to carry out piloted flights to test and validate the systems needed for exploration beyond low Earth orbit. He expected, by 2025, new spacecraft intended for long journeys that would permit America to begin the first ever crewed missions beyond the moon into deep space—starting with sending astronauts to an asteroid for the first time in history. Those deep space assaults are prologue to placing humans in orbit around Mars, returning them safely to Earth, with a human landing on Mars to follow.

In stepping up to Obama’s space plan, NASA has begun planning an asteroid mission as the first part of a “capability-driven” approach to explore multiple deep space destinations, acknowledging that the space agency’s ultimate destination for human exploration is Mars.

Success requires viable asteroid targets. NASA has identified two accessible space rocks—asteroids 2009 HC and 2000 SG344, NEOs for space travelers to examine in the 2023–2025 time period. But getting there is technology demanding, supported by advanced in-space propulsion, a deep space exploration module that provides adequate habitation for crews, radiation protection, and autonomous operations. A dedicated crewed NEO mission will check out and validate new deep space systems. What is most important, in my point of view, is to ramp up our ability for NEO exploration crew members to perform at demanding destinations while, at the same time, advance our technological skills with each step forward.

So let’s look at the exploration, science, development, commerce, and security pieces that are tied to NEOs.

Number one is that near-Earth objects have thumped our world over the ages, and assuredly will in the future. NEOs can shake up but also shape our life-sustaining ecosystem. To assure the survival and guarantee the movement of humanity into space, I feel it is vital we come to terms with NEOs that may have Earth within their crosshairs. Doing so harnesses the technological muscle to not only
encounter
but also
counter
these objects, and it also allows us to use space objects as resource and exploration stepping-stones to Mars, thereby helping to extend the human presence into space.

Earth on the receiving end of a large asteroid

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Illustration Credit 5.2
)

Over the eons, it has been a celestial slugfest. Comets and asteroids have struck Earth since its formation 4.5 billion years ago, bringing seeds of life to Earth early in its history and shattering life by altering the globe’s ecosystem, such as hypothesized as the cause for the extinction of dinosaurs.

First of all, I’m not saying you should lose sleep worrying about a giant space rock hitting our world. However, experts that I’ve listened to advise that, while the chances of a destructive impact here on Earth in the near future are small, they are not zero—and the consequence of a hefty NEO colliding with the planet would be extreme.

Itokawa, a large asteroid surveyed by Japan’s Hayabusa probe, contrasted with the International Space Station

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Illustration Credit 5.3
)

For the moment, put aside that mental image of movie star Bruce Willis and his team wrestling with a massive space rock in the hit film
Armageddon
. It turns out that smaller “airbursters” are the more disconcerting sky-slamming flotsam from space. They can cause localized destruction and may infringe upon our air space with surprisingly little warning time.

For example, the 1908 Tunguska event is a saga in which a rocky impactor detonated over remote Siberian real estate, knocking down about 500,000 acres of forest. Supercomputer simulation work led by Sandia National Laboratories principal investigator Mark Boslough suggests that the incoming
object was roughly 130 feet in diameter. The object broke up in a cascading way, leading to a rapidly expanding fireball and subsequent blast wave that hit the ground, stirring up a wind strong enough to actually blow over trees. Because smaller asteroids approach Earth statistically more often than larger ones, efforts to detect smaller NEOs would appear to be in order. It is estimated that these smaller objects could impact Earth on average every 2 to 12 years.

More recently, in October 2009, a fireball blast in daylight was observed and recorded over an island region of Indonesia. That atmospheric entry of a small asteroid, perhaps just 33 feet across, rocked their world with a projected energy release of about 50 kilotons, equal to some 110,000 pounds of TNT explosive. Eyewitnesses reported a bright fireball, accompanied by an explosion and a lasting dust cloud.

You can easily visit an impact site of an iron asteroid by traveling to the Barringer meteorite crater, known popularly as Meteor Crater, near Winslow, Arizona. It was formed some 50,000 years ago in flat-lying sedimentary rocks of the southern Colorado Plateau. When that cosmic interloper grooved into Earth tens of thousands of years ago, more than 175 million metric tons of rock were hurled into the sky and redeposited on the crater rim and the surrounding terrain in a matter of a few seconds.

There is an ongoing debate as to the downfall of dinosaurs at the end of the Cretaceous geologic period, 65 million years ago, and the growing consensus is that a mega-asteroid impact caused their mass extinction. That viewpoint stirred up a comment by science-fiction writer Larry Niven: “The dinosaurs became extinct because they didn’t have a space program. And
if we become extinct because we don’t have a space program, it’ll serve us right!” That is insight, and I can’t say it much more directly than Niven has.