Thursday, December 28, 2006

Tug of love proposed

In an earlier post I outlined the danger posed by the near-Earth asteroid Apophis, which it is thought may smash into our blue Earth in the year 2036.

According to a news item this week, NASA is on the case “drawing up a shortlist of ideas to be unveiled early next year for diverting” Apophis from its potentially disastrous course.

“NASA’s plan,” we’re informed, “is to engineer a minor shift in the asteroid’s trajectory that would make it miss Earth by a wider margin on this and all subsequent passes.”

The most favoured option to accomplish this appears to be the deployment of what’s known as a “gravitational tractor”. The principle is outlined in the article from the November/December issue of Australian Sky & Telescope magazine from which I drew for my previous post:

Park a spacecraft in close proximity to the asteroid, cant it’s highly efficient solar- or nuclear-powered ion thrusters to the side so their plumes don’t hit the object, and hover beside it for several months or more with long, continuous thrusting. Due to the spacecraft’s and asteroid’s gravitational attraction on each other, the vehicle effectively tows the rock along with it using gravity as the towline.

If we launched a tugboat to Apophis before the 2029 close approach, we would only need to move the asteroid a few hundred metres to miss the 2036 keyhole, rather than several thousand kilometres to miss the entire planet. The tiny change in the asteroid’s orbit could be accomplished with only a 1-tonne solar-electric-propulsion spacecraft similar to NASA’s low-cost Deep Space 1 mission.

According to this week’s news item,

Lu calculates that a 20-tonne craft gently firing its thrusters could safely deflect a typical 198m asteroid in about a year, assuming there was 20 years of warning to launch and get the blocker into position.

Lu’s approach is far more cautious than that proposed by Hollywood in films such as Deep Impact or Armageddon. In the latter, the character played by Bruce Willis dies leading a team of astronauts who drill into an Earth-bound asteroid to plant a nuclear weapon that destroys it, and him along with it.

Lu and others say such an approach would increase the threat by turning a single piece of rock into smaller chunks that could bombard the planet.

Indeed, let’s hope Lu’s smart ideas win the day over certain ham-fisted mainstream approaches. We must certainly resist the reflex to throw bombs at yet another problem.

5 Comments:

Blogger Caz said...

Well, yeah, just call Bruce Willis, darned obvious.

Ben Affleck can tag along, if he must, but he's probably not really needed, other than to make Bruce look good.

We're in safe hands.

29/12/06 11:24 PM  
Blogger Caz said...

Aaah, you've switched over to the new blogger!

I tried to (having resisted), thinking from the instructions that all you needed to do was start using your Google login.

Nothing so simple, of course.

I've NO idea how to move my blog over to the new blogger.

And before you ask, yep, I read all of the paltry instructions, and it didn't help me one iota. Any tips for me Jacob?

29/12/06 11:27 PM  
Blogger Jacob A. Stam said...

I just went through the hoops from the Blogger Dashboard. Part of the deal is that one has to sign up for a 'google account', which entails setting up an acct id with an email address and password.

Just follow the prompts from the Dashboard (you may need to log out & back in for the prompts to appear).

The process takes more than the "few minutes" claimed. I waited for about half an hour then gave up. I logged in later to find the process complete.

Let me know how you go...

29/12/06 11:35 PM  
Blogger Caz said...

No, Jacob, I've had a google account since gmail was in beta - early adopter.

I signed up using that log on, but NO BLOG - my blog was not there; it asked if I wanted to create a blog.

Baaahhhhhh!!!!!!!!!!!!!!!!

1/1/07 3:19 PM  
Blogger Jacob A. Stam said...

At this stage I can only offer the dubious advice to contact the Blogger help desk for a solution.

Then again, I'm not sure it's worth it to 'upgrade'. I haven't really had much of a chance to check out the 'new blogger', but so far I can't really see any compelling benefits to switch across.

In fact, it REALLY IS MORE TROUBLE THAN IT'S WORTH!!

Every time I go into the Blogger Dashboard to create a new, or edit an existing, post, I have to log in with my blogger id, and then it tells me I have to log in to my Google Account. I've told it to 'Remember me on this computer' countless times, but to NO AVAIL.

I even have to go through all this login shit to post a comment on my own bloody blog!!!

And every time I want to post a comment, I get a 'standard' IE dialog asking "Do you want to display the non-secure items?"

AAAAARRRRGGGGHHHHHHHH!!!!

My advice to would-be upgraders:

DON'T FUCKING DO IT!!!!

3/1/07 11:10 PM  

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