Space Combat is still a combat encounter using Characteristic and Skill Tests -- just on a different playing field. The initiative is different and the question "what action do I take?" is brought to the foreground, but the core rules of how they are performed remains the same. During this combat, the character's personal characteristics are still being tested (i.e. Firing the cannons of the ship is a Ballistic Test by the character directing the cannons // The pilot usually has to make a Pilot (Space Craft) Skill Test to fly the ship in advanced ways). The same restrictions on these tests apply: no more than a +/- 60 modifier to any test.
You've already quoted the most crucial part of this.
The maximum total bonus that can be applied to a test is +60. Conversely, the maximum total penalty that can be applied to a test is –60.
~Rogue Trader Core Handbook: Page 244
There is, of course, also these:
The maximum modifier that can be applied to a Skill Test or Characteristic Test is +60 or –60. ~Deathwatch, Final Sanction: Page 10
The maximum modifier that can be applied to a Skill Test or Characteristic Test is +60 or –60. ~Black Crusade, Broken Chains: Page 10
The maximum modifier that can be applied to a Skill Test or Characteristic Test is +60 or –60. ~Only War, Eleventh Hour: Page 10
There isn't much room for interpretation here. Fantasy Flight Games has kept this core mechanic constant throughout their Warhammer 40k titles (The only exception to this may be Dark Heresy 2nd Edition. I haven't gotten the chance to look through it yet, so I can't be 100% sure), thus if playing by RAW then yes, 60 is the limit in either direction.
The only way out of this I can see would be what Skeith said earlier -- using a Fate Point to get +10 extra.