Likely a questions for Bob Bruninga....
Since NMARS and RAFT have both re-entered the atmosphere, how is it FCAL and ANDE are still in orbit since they were lauched at the same time? I could understand a slight difference, but it's been weeks since they re-entered. Did they have a different trajectory or less drag than the first 2? Curious minds...
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[email protected] wrote:
I could understand a slight difference, but it's been weeks since they re-entered.
It's all about mass and aerodynamics (the *ballistic coefficient* is how engineers talk about the issue). RAFT and NMARS were deployed together and were both 5 inch cubes. NMARS deorbited earlier because it had a lower mass and was decelerated by the atmosphere more quickly. Think about throwing a baseball vs a whiffle ball ... if you throw both at the same velocity, the baseball will go much further.
FCAL and ANDE are both spheres so they slip through the atmosphere easier than the two cubesats. I can't speak to their mass, perhaps Bob can once he returns from his trip. My earlier analogy falls apart here ... I have never tried to throw a baseball and a *Rubik's* *Cube together*!
Since NMARS and RAFT have both re-entered the atmosphere, how is it FCAL and ANDE are still in orbit since they were lauched at the same time?
ANDE was a perfect sphere with no external drag components and weighed 50 kg. RAFT and NMARS were less aerodynamic cubes and both had extrnal whip antnenas an hopefully a 4 foot long wire HF antenna (though we think they were not fully deployed)...
So ANDE's mass is 15 times as much but it's cross section area is only 10 times larger and much smoother.