Currently contracted until 2014 Interlagos could well have its contract renewed until 2020 but only if major changes are made to the circuit including its saftey features and moving the paddock and pits complex to the straight after the initial Senna S complex.
Bernie Ecclestone already confirmed last year that he wants to see the Brazillian Grand Prix stay on the calancer and no mention has been made of any other circuit other than Interlagos being in the running.
With the plans and requirements now released though Interlagos will need to be bought up to the standards of new circuits with expanded pits and paddock which should be located after turn three. This will allow for the main, current pit, straight to be moved inwards from the outer wall.
Currently the pit straight starts far back before turn 15 where it curves before straightening out, with little space to the outside of the straight before a major road it hasn’t been possible to add more than a small escape area. this escape area was added last year following the death of a driver in a Stock Car Race, there was a similar incident in 2007 in both cases the cars hitting the barrier and bouncing back into the line of oncoming cars. A major incident in the 2003 Brazilian Grand Prix on the straight led to minor injuries for Fernando Alonso, hitting debris strewn across the track from Webber hitting the barrier.
It is likely when changes are made the straight will be moved to where the current pits are but should replicate the famous curved entrance with the current straight likely to become a tarmac run off area though a gravel trap may be chosen as Interlagos is often used for motorbike racing. Whether these changes will be possible without closing the track and the Brazilian grand Prix being missing from the calendar for one year isn’t clear but they may follow the example of Silverstone and complete work in stages with the new pits and paddock built while the current pits remain in use.