**Tell us what’s happening:**

My value is still far of the solution. And, how can I take update the object? I want to remove avgAlt and set orbitalPeriod.

How may I set a new property in arr?

**Your code so far**

```
function orbitalPeriod(arr) {
var GM = 398600.4418;
var earthRadius = 6367.4447;
for(let i=0;i<arr.length;i++){
let orbitalPeriod= Math.sqrt(4*Math.pow(Math.PI,2)+(earthRadius+arr[i]["avgAlt"]/(GM)))
delete arr[i]["avgAlt"];
return arr,orbitalPeriod
}
}
orbitalPeriod([{name : "sputnik", avgAlt : 35873.5553}]);
```

**Your browser information:**

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36`

.

**Challenge:** Map the Debris

**Link to the challenge:**