posted 04-07-2004 06:58 PM               

Also testifying were Wayne Van Citters, Director of the Division of Astronomical Sciences, National Science Foundation; Lindley Johnson, Program Manager of the NASA NEO Observation Program; Grant Stokes, Associate Head of the Aerospace Division of the MIT Lincoln Laboratory and chair of the recent NASA Science Definition Team on sub-km NEOs; and Michael Griffin, Head of the Space Department of the John Hopkins University Applied Physics Lab.

Though Senator/Astronaut Bill Nelson appeared briefly to submit written questions to those testifying, only Chairman Brownback was present for the entire session.

Testimony focused on the threat and promise of NEOs. Based on recent studies focusing on global-devastation (extinction risk) sized asteroids (1 kilometer or over), there are believed to be 1100 (down from a previously believed 2000) candidate NEOs, of which approximately 700 have been identified and tracked. The remaining 400 still need to be located.

While impacts of a < 1km NEO are thought to occur once every 100,000 years or so, the chances of a smaller but still region-devastating impact are greater. For each of the 1100 large NEOs, there are believed to be 100 additional NEOs of sizes 100 meters or greater. These smaller sized asteroids have an impact rate of 1 for every few hundred to 1000 years. An asteroid 100 meters wide would probably never reach the ground but would explode in the air similar to the 1908 Tunguska impact or the 1947 impact over Siberia.

At current, neither NASA or the National Science Foundation track these smaller asteroids. They are only detected when they pass close to the Earth, giving us possibly as little as a day to prepare for an impact should it be on a direct course.

One the recommendations made to Congress today was that NASA be directed to fund a detection effort to catalogue at least 90% of these smaller NEOs. This could be accomplished by a space-based observatory or over longer periods using ground-based equipment.

Something to consider (that was raised by one of those testifying): while we much better know the chances of being hit by lightening, a majority of humans will never be struck. Yet, we know its a certainty that eventually a 1km or larger NEO will strike and unless we are prepared to act, then all human life will end.

At current, scientists estimate that we would need three decades warning to successfully identify, plan, and implement a mission to deflect an asteroid on an Earth impact trajectory.

The U.S. government exists primarily to protect its citizens from harm. At current, there are no active programs in planning or implementation to deflect an asteroid impact.

Which brings us to Lu's and Schweickart's testimony. Lu raised the point that when it comes to deflecting asteroids, we know very little and the best way to learn is to go study them. He said that our first attempt to purposely move an asteroid should not wait until we must move one to save our lives. There are too many unknown variables.

Not that we are talking about moving an asteroid by that much -- only a couple of centimeters would suffice if applied approximately a decade before the projected impact. Yet our chemical rockets -- such as what was used to launch Lu on the Space Shuttle and Schweickart on the Saturn V would not suffice. Fortunately, NASA is already developing the solution: Project Prometheus.

The B612 Foundation (through Lu's and Schweickart's testimony) called today for Congress to direct NASA to design and launch a Discovery-class mission that would significantly alter the orbit of an asteroid in a controlled manner by 2015. Why 2015? Lu explained that this date corresponded with when the first operational uses of Project Prometheus -- NASA's nuclear-powered propulsion effort -- would be ready. The Jupiter Icy-Moons Mission is currently planned to launch in 2012. Altering the technology developed for that mission should not be too difficult and could set the stage for a follow-on crewed mission (for which Lu said he would eagerly volunteer).

Schweickart explained that in addition to the safety benefits of such a mission, such a craft would also pave the way towards tapping the great resources that are withheld within the asteroids. He envisioned a day when a NEO impact threat was detected and instead of declaring an emergency, NASA (or whatever agency) would simply contract the services of the Ace Mining Company to nudge the asteroid in their normal course of work. All the raw materials needed for our exploration and settlement of the solar system can be found in the asteroids, he said.

Lu noted that such a mission would mark the first time humans would become active participants in the shaping of their solar system instead of interested observers.

Brownback focused most of his questions on trying to understand the threat, its timeline and at one point, what international cooperation existed (answer: not much; there seems to be an attitude that if NASA / the U.S. is doing this already then why not simply allow us to continue and only help when asked or needed). The senator noted that Representative Rohrbacher had introduced a bill in the House that covered some of the requests made of the Senate during the hearing and that Brownback would be looking at a similar introduction on his side of Congress.