Would this work?

[SemiaCloud]

Would it be possible to fly spaceshipone/spaceshiptwo into space - with whiteknight/whiteknight2 still attached?

[Bill Phil]

Nope.

You would need ONE BIG ARSE BOOSTER. (TBH, IDK the mass of whiteknight...)

[Kryten]

SS1 could barely reach space as it was, and there's a good chance SS2 actually can't, at least with the current engine.

[Kibble]

Its possible if you stick a big rocket on the back.

[SemiaCloud]

Thanks everyone!

[Tex_NL]

Its possible if you stick a big rocket on the back.

No it isn't.

If you would stick a big enough rocket to it WhiteKnight would not be able to take off.

[Deutherius]

No it isn't.

If you would stick a big enough rocket to it WhiteKnight would not be able to take off.

Nodoby said it has to take off under its own power (of the SSO/WK). It can just be strapped to a big rocket as a payload - think Space Shuttle or Buran. I wouldn't write it off as impossible. Impractical, on the other hand... Very much so.