That would be a dream guest for many space collectors. He has only participated in one (mailed in items) signing and the base fee was as I recall $495 per autograph with extras for mission inscription, personalisation, inscription and a premium for crew completions and multi-signed items. Not sure how many would be able or willing to pay around £280 for one single autograph at a show !
Ah. I didn't know that. I'm guessing he'd only be invited if he charged a lot less than that Otherwise as you say, doubt he'd be too busy.
Hope they get him one day.
No problem. If Dave & Garry could get him to attend and charge a similar fee as Buzz Aldrin last year I'm sure there wouldn't be too much trouble in keeping JY busy!