Wednesday, March 20, 2013

NASA Month: Interviews & Asteroids

All this month, I'm NASA! This means every weekday in March will feature a new post about NASA, and I'm hosting a giant giveaway in order to encourage people to spread the NASA love. For more information on the giveaway, check out this post.

Today, I have the great honor of interviewing Paul Abell, Lead Scientists for Planetary Small Bodies at NASA Johnson Space Center, and Amy Sisson, Science Fiction Writer and Librarian.  This time, I asked all about asteroids and their impact (haha, get it?) on our Earth. 


Interviews & Asteroids

Paul Abell, Lead Scientist for Planetary Small Bodies, NASA Johnson Space Center
Amy Sisson, Science Fiction Writer and Librarian
March 2013

1) How likely is it that a large asteroid or meteor--of the kind that wiped out the dinosaurs--will hit Earth again?

The object responsible for the Chicxulub impact that wiped out the dinosaurs 65 million years ago is believed to have been about 10 km (6.2 miles) in diameter. Fortunately, there aren’t too many near-Earth asteroids of this size still flying around out there, and the large asteroids in the asteroid belt are generally in stable orbits and aren’t a threat to us.

A screenshot of the Chelyabinsk asteroid
But an object doesn’t have to be that big to cause massive destruction. The object that exploded over Chelyabinsk in Russia just last month caused an awful lot of damage (but thankfully no deaths), and it was only about 20 meters (65 feet) in diameter. It exploded high up in the atmosphere before it could hit the ground, but even so it injured more than 1,500 people, and produced a shock wave with far more force than the nuclear bombs that were detonated at Hiroshima and Nagasaki during World War II. If this had happened at a lower altitude right over a big city like New York or Houston, the casualties would have been a lot worse.

On average, objects the size of the Chelyabinsk meteor will hit the Earth once every 100 years – which may make people think that “OK, we’re safe from that size object for another hundred years.” But the frequency of these impacts is on average. That means that one could hit us today and another one could hit us tomorrow, and then maybe we would go a couple of hundred years without a hit. This means we need to be on alert all the time, because we can’t predict when statistics are going to work in our favor and when they’re not.

2) What kinds of things does NASA have in place to protect Earth from such an event? Is the movie Armageddon a likely scenario or just crazy Hollywood?

Armageddon was crazy Hollywood, placing story and excitement over any resemblance to reality. The size, speed, and physical nature of the asteroid were very unrealistic, as was NASA’s fictional method of dealing with it. For starters, no country currently has a space vehicle that could send astronauts flying after a speeding asteroid that way.

But the movie did get two key factors right. First, they mentioned, and it’s true, that NASA simply does not have the funding to watch every part of the sky at all times. Even with unlimited money, asteroids are small, dark, and moving fast against the backdrop of space, making them difficult to spot. Ideally, NASA would like to build and operate a space-based telescope to help find the potentially dangerous asteroids that travel very close to or near our own orbit. Such a telescope would work 24 hours a day and could effectively look for asteroids coming from the general direction of the sun. This is something ground-based telescopes can’t do, because we can only use them at night.

Armageddon was also correct that if a massive asteroid is speeding towards us, we most likely won’t be able to just blast it with a nuclear bomb. In the movie, Bruce Willis and his team first drilled down into the asteroid so that the nuclear bomb would split it into two halves that would both miss the earth. That was fun for the movie, but it’s not the way NASA would do it. In reality, it would be better to use a nuclear bomb to simply nudge the asteroid off course slightly – but to do that, we would need to know about the asteroid well in advance, so that a little nudge while the asteroid is still far away would make it miss us by a safe margin. That’s where the funding for early detection comes in.

So yes, NASA thinks about this stuff all the time. What they don’t have is a space shuttle-like vehicle that can send people to an asteroid at the last minute, or even a rocket that could definitely target an asteroid with a nuclear bomb. They do have many theoretical scenarios in place, but what they will be able to do when the time comes will depend a lot on what funding and what technology is available at the time. Having as much advance notice as possible of an incoming asteroid is the key, and that means funding is required to try and survey all the near-Earth asteroids that are out there. There’s a saying: Asteroids are nature’s way of asking ‘How’s that space program coming along?’”

3) Is it possible in the future for astronauts to visit large asteroids? What might they discover?

It’s very possible for astronauts to visit large asteroids. In fact, in many ways it would be easier to do that than to send astronauts to Mars, or even back to the Moon. NASA has spent a lot of time and effort over the last few years developing the concept of a crewed mission to a near-Earth asteroid. Since asteroids are always moving, we can’t just fly from the Earth straight to an asteroid, so we have to understand their orbits and pick an asteroid that we can get to and from in a reasonable amount of time. NASA will need a space vehicle capable of supporting a four-person crew for a round trip that would last several months, with food, water, fuel, and shielding against solar and cosmic radiation.

What will they discover? To plan the mission correctly, they’ll need to have a good idea in advance whether the asteroid is rocky or metallic in its composition, so they’ll probably first send out a robotic spacecraft to check things out. Finding water (in ice form or trapped in rock) would be a terrific bonus, because water-rich asteroids can eventually be used to supply fuel and drinkable water to astronaut crews on even longer missions, such as to Mars. Learning how to get at and use that water can help NASA figure out ways to use similar resources on Mars’ two moons (Phobos and Deimos, which are both actually captured asteroids), which could help us get astronauts to the surface of Mars and to other destinations in the solar system.

But back to that asteroid… Well, there won’t be much gravity there, and there certainly won’t be razor-sharp shards of metal flying around the asteroid the way it happened in Armageddon. But even so, the first human trip to an asteroid will be equally exciting, and sure to result in scientific discoveries that haven’t even occurred to us yet.

This post is a part of the month-long celebration of NASA I'm hosting on my blog. In order to encourage people to celebrate NASA, I'm also hosting a giveaway!

One grand prize winner will receive all the books in the recent Breathless Reads tour, as well as ARCs of two anthologies and a signed Breathless Reads poster:

As well as swag from NASA, courtesy of Kate @ Ex Libris:

To celebrate NASA creatively: you could blog about why you like NASA, you could reach out to an astronaut for an interview, you could make space fan art, you could sing a song about NASA, you do a vlog, you make a list of all the ways NASA rocks...any of this counts! Just celebrate NASA in some awesome way, post it online, and include the link in the Rafflecopter. I even set that part of the entry open for multiple entries, so you could blog and vlog and Facebook and tumblr and Pinterest about NASA and they all count. The only requirements: post a link back to this contest, and put the full URL of the site in the Rafflecopter. Full details here.

To enter: be sure to read the full rules and terms of the contest here. Then fill out the Rafflecopter below:

a Rafflecopter giveaway

1 comment:

K M Kelly said...

I'm loving these NASA posts I keep seeing cropping up in the bloggosphere. I talk about NASA a bit on my own blog anyway since I'm rather into all things space, but since the competition is US only I won't join in formally, but I'm with you in spirit and looking forward to seeing more interesting posts on this subject :-)