It's a fascinating thing, you know, we're kind of interested in astrobiology because, you know, asteroids could have conceivably been the... the mechanism for bringing life to Earth. But as, they estimate, I... I think the figure seems to change from time to time, but they estimate there are a couple of thousand, let's say, near… near Earth objects that could… that are a kilometer or larger. A kilometer… an impact by a kilometer would destroy a large percentage of the world's population. And the… so a near Earth object is a asteroid or, I guess, they'd include comets as well, that come between the orbit of the Earth and the moon. And if you detect those, and then you take measurements on multiple orbits of the near Earth object, you can make, you can predict, with very high accuracy, the probable course, because, you know, it's straight Newtonian physics. I don't think there's any relativistic physics, because they're not going that fast. So, they've detected, they think, maybe 80, 85% of the kilometer or larger. Now, they recently got authorization, in the last few years, to track stuff that’s something over a hundred thousand, I mean.. a hundred – I forgot the level — I mean, you know, it's less…less than a kilo… less than a kilometer.... and that's a couple of hundred thousand. Now, the way they do that, there's a sort of central registry, and professional or amateur, astronomers will detect these near Earth objects and then other, mostly amateurs, are enlisted to follow their orbits and make the appropriate measurements. And that's all pooled in a big database that the Air Force runs.
[Q] So, when you say there's a hundred thousand, you mean there's a hundred thousand objects that would qualify for a… ?
Yeah, less than a kilometer. But big enough to... if they struck a city, you know, it would destroy the city. But it wouldn't cause a world-wide cataclysm, but it would… it would probably have world-wide effects, you know, if it's a few hundred… a few hundred meters... 300 meters, I think is the bottom limit, something like that. Okay, well, so astrobiology is kind of interested in them because a lot of the history of the Earth, of early life, was dependent on these missile strikes. And characteristic, of the… of the Mars geology are many, many impact sites. And that's true for many objects in space, so, you know, we… we kind of want to understand the dynamics of that. But one of the reasons - and some of the astronauts have taken a real interest in that - Rusty Schweickart, one of the early astronauts, he's focused on that project. And the notion is they… they might be able to have an interventional… interventional act that… that would change the orbit. You see, usually they can find these things 10, 15, 20 years before their… the possible impact, so that means you have a long time to effect any change. And also, if you just, change the orbital… velocity, or change the orbit, just slightly, you know, but over the course of eight, ten years... it could be… it could be changed such that it wouldn't hit the Earth. So you don't have to have a huge explosion and, you know, blow it up, or anything. So, there are various strategies that have been proposed. One of them, which is… is not going to happen, I mean it shouldn't happen, is to blow it up, because instead of having one big potential impact, you have a lot of ones… a lot of them, and it's difficult to predict their orbits. So… but there's a possibility of a gravitational tug. You know, you fly a spaceship up and… and with the gravitational pull, then you gradually sort of pull it away, just by, you know, it's kind of following. The other thing is actually tether it, you know, to attach a motor to it, to land, or do it… do it probably robotically. And they’re actually planning missions... there have been missions to asteroids. About four or five years ago, we had an orbital mission on an… on an asteroid called Eros, and it orbited it for about a year, you know, at a very close orbit and a very slow one. I think it's about the size of Bermuda, right, Eros.
[Q] Could you ever land on it?
They did land. It was a robotic landing. They had a soft landing, which was unexpected. And I was at headquarters then, you know, I was with the Associate Administrator for Space Science. He was out of his mind, you know, to think, I mean, he was so freaking excited! They… they hadn't expected a soft landing. And they actually photographed it, right down to the landing. Then everybody said, okay, there was… there was a little juice left, you know, they had some power left, and they said, we'll lift it off again, right? And we'll get an image of the impact. Nobody’d ever seen that! You know, just an impact, just after it’d been made. Well, it turns out that they couldn't, you know, it was not feasible to do that. But there was this, you know, great excitement about it. Now, there's... there are plans for a… for a human landing. Way in the future, I'd say — it's not… it's not a high priority. But they're… they're, there's another mission, I think it's in orbit now; it's en… en route to do some orbital investigations, both the Europeans and the Japanese... the Japanese, they had a really risky mission. They were going to have a landing and a… and a capture – you know, collecting material, and a lift off, dispatching the, collecting the vehicle, parachute it back to earth. It didn't work. I mean, the Japanese have had a tough time, actually, with their space program. They've just recently had a good launch, a good success. But it's tough doing this stuff. You know, everybody's all crazy about these, this private enterprise they… they shout and think, that's what NASA did 40 years ago, they had a sub-orbital flight with a person in it, you know, that was the period of John Glenn and everything. But there… there's a lot of... in… in this meeting, there's going to be quite a strong focus on… on private enterprise to provide small… small launch vehicles, inexpensive ones, and... and have them do it, not, you know, as a business of some sort. You know, it's a major topic of conversation now, the idea that free enterprise will be able to take over much of this, which is, I think, you know, possible. But it takes a lot of imagination and boy, a lot of capital, and a lot of risk. It's a lot easier to invest in bonds.
