Hi, I've read that SOHO (SOlar and Heliospheric Observatory) is orbiting around the L1 point. I remember this point being unstable (that is, that something in orbit will diverge from stability). How are the corrections made for this orbit ? Does it really cost a tiny amount of fuel, or is the fuel somehow transfered to SOHO regularly, like it is for the ISS ? Or is there a metastable state in between that I don't know about ? Thanks.