Re: asteroids with orbit between earth and sun

Hi Michal,

Yes, there are asteroids which come close to the Earth and also close to the Sun. Asteroids which come close to the Earth are called "Near Earth Asteroids", or NEAs, and they are usually divided up into three classes, Amors, Apollos, and Atens. Amor asteroids approach the Earth's orbit from the outside, Apollo asteroids cross the Earth's orbit, and Aten asteroids approach the Earth's orbit from the inside. It sounds like the Apollo class of asteroids is the one you're interested in. http:// www.seds.org/nineplanets/nineplanets/asteroids.html contains a nice description of the asteroid classes, as well as links to lists of NEAs, at http://cfa- www.harvard.edu/cfa/ps/lists/Atens.html , http://cfa- www.harvard.edu/cfa/ps/lists/Apollos.html and http://cfa- www.harvard.edu/cfa/ps/lists/Amors.html . NASA has a program to look for NEAs, called the Near Earth Asteroid Tracking project, which can be found at http://neat.jpl.nasa.gov .

I'm not sure that an NEA which approached the Sun would be all that helpful for studying the Sun, though. You could use the asteroid to provide some mass for shielding to help protect your spacecraft from Solar radiation, but in order to use it you'd first have to rendezvous with the asteroid. I think this would likely take a lot more fuel than you'd save. You'd probably be better off building a bigger, better protected spacecraft and sending it directly without the asteroid. There are already a number of spacecraft which study the Sun (from a safe distance). You might be interested in http://soho.nascom.nasa.gov/ mission , for example. I'm not sure I've understood how you suggest using the asteroid to study the Sun. If you want to talk about it further, you can reach me by email at StevenLevin@we.mediaone.net or send a follow-up question through the Mad Scientist Network.