The decision was based on spectral measurements by the orbiting Mars Global Surveyor, which showed an unusual concentration of haematite, a form of iron oxide.

• 决定建立在由围绕火星飞行的火星全球探测器所做出的光谱测量基础上，其中显示了不同寻常的赤铁矿（氧化铁的一种）含量。