View Full Version : Aerobraking Mars Orbiter Surprised Scientists

2006-Sep-21, 02:19 PM
The Mars Reconnaissance Orbiter (MRO) has completed aerobraking and its primary science phase will soon begin in earnest. MRO’s Project Scientist and members of the Navigation Team discuss the intricacies and challenges of aerobraking in Mars’ ever-changing atmosphere.

Read the full blog entry (http://www.universetoday.com/2006/09/21/aerobraking-mars-orbiter-surprised-scientists/)

2006-Sep-21, 06:00 PM
It is interesting how much the Martian atmosphere varies in term of density at the high altitudes. These aerobraking missions are the most detailed way we have of measuring this. I wonder how much variation an aerobraking mission around Jupiter would experience. I'm guessing it would be a lot less.

2006-Sep-21, 07:33 PM
On the other hand, didn't the probe that Galileo launched (don't recall if that probe had a name) enter the Jovian atmosphere in some kind of storm or hole such that there was almost no water detected? with the massive storms, I would imagine that Jupiter would have variance in density at high altitude.

2006-Sep-25, 07:28 PM
Being lucky enough to have watched storms fly around both planets, I am anxious to see what they find out over Mars, but am also thinking that the atmosphere over Jupiter would be more of a "Destruction Derby" challenge. Perhaps far enough out could go, but just a bit too close and massive gravity catches. Also, the obvious trails of varying speed atmosphere are very unstable. More than once I have seen storm cover (I can only guess) a third of a ring in one night. We kept going back to check on that and finally, after nearly crossing the full face of the ring, here comes the tail of the storm! Big dusty storms on Mars have blotted out any chance to study it far too often. Cheers and good luck to the studies!

2006-Sep-25, 10:03 PM
But the atmospheric density that MRO actually experienced was much different than what was predicted by the Mars GRAM.

At some points in the atmosphere, we saw a difference in the atmospheric density by a factor of 1.3, which means it was 30% higher than the model, said Han You, Navigation Team Chief for MRO. Thats quite a bit, but around the south pole we saw an even larger scale factor of up to 4.5, so that means it was 350% off of the Mars GRAM model.

Sounds exactly like the stuff Jerry has been on about, atmospheric densities just aren't modelled correctly, and I think Jerry's ideas get more and more supporting evidence.