Precocious Sauber driver Sergio Perez retired from last Sunday's Malaysian Grand Prix when an unidentified object penetrated the chassis of his car. The destructive path taken by the debris has been explained in vivid terms by Sauber technical director James Key:
"Sergio hit what he believed was a piece of wing or something, because it must have been big enough for him to see. It appeared to come off the car in front, which was a Toro Rosso, but subsequently we found out that they also found some damage on their car, so it looks like this piece was lying on the ground beforehand. What happened was pretty frightening. It damaged the front wing quite badly and it damaged the front of the floor. Then, it went through the side of the lower part of the chassis, in the boat area [on the underside of the nose], and pierced that. It went straight through the Zylon panel, straight through the chassis, and then into the ECU. It killed the ECU, which stopped the car, and then rolled along. It then went into the sidepod and then out the car – damaging the impact structures in the sidepod itself. So whatever it was it was either travelling very quickly, or it was very heavy and had a lot of momentum."
The Toro Rosso in front was that of Jaime Alguersuari, with whom Perez was battling for 13th place. The possibility that some ballast became detached from the Toro Rosso, has now been ruled out after the Italian team claimed that Alguesuari's car was perfectly intact at the end of the race. So what did cause Perez's retirement?
The first thing to note is that something fell off the rear of Vitaly Petrov's Lotus-Renault, going into turn 1 on lap 21. The object came to rest on the outside of the turn, and appeared to disappear shortly thereafter. It might have been retrieved by a wing-footed marshal, but it might also have been picked up by another car, and shed a few laps later in front of Alguesuari and Perez. However, as David Coulthard noted on the BBC commentary at the time, the object appeared to be a mere carbonfibre appendage, and thus unlikely to penetrate the chassis of another car.
Of more relevance, perhaps, is the fact that after his ECU was killed, Perez coasted to a halt on the inside of the circuit just after turn 14, on what was his 24th lap. This implies that the damage was incurred somewhere between the uphill hairpin of turn 9 and the downhill switchback of turns 12 and 13. And intriguingly, in the couple of laps before Perez retired, the right-hander of turn 11 appeared to become quite treacherous.
Nick Heidfeld, for one, left the road at turn 11 on lap 22, crossing the gravel before rejoining. It's possible that this excursion dragged something onto the margins of the track, or pulled some ballast off the Lotus-Renault. If so, however, there is no visual evidence of it during the couple of laps between Heidfeld's detour and Perez's retirement.
On lap 24, the other Sauber of Kamui Kobayashi lost 10th place to Mark Webber when the Japanese pilot slid wide at turn 11. Once again, there is no visual evidence of anything being pulled onto the racing line from the margins of the track. The only other car to pass through turn 11 before the arrival of Alguesuari and Perez on this lap was Rosberg, unseen by the television cameras. 'Britney' could conceivably have run wide over the kerb, flipping something onto the racing line. But if so, then Nico lost no time in the process, being 54secs behind the leader both before and after.
So, in the absence of further televisual evidence, or a confession of missing ballast from one of the teams, this seems likely to remain a mystery...