Author Topic: MSL Q&A  (Read 75777 times)

Offline Jim

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Re: MSL Q&A
« Reply #220 on: 08/13/2013 05:33 PM »
Imagine being on a falling hexagon and throwing a 150 kg weight overboard.

Now imagine being on the same falling hexagon and throwing (6) 25 weights overboard in a hexagonal pattern.

I'm imagining... were the ballasts ejected all at the same time?
Yes

The spacecraft was balanced for the cruise.  It spun for stability.
Since the entry vehicle was going to use a lifting entry, it needed to have an offset cg and so weights were ejected before entry.  However, JPL wanted to have a balanced vehicle for parachute deployment, so after entry more weights were ejected to bring the vehicle back into balance.

Offline ClaytonBirchenough

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Re: MSL Q&A
« Reply #221 on: 08/13/2013 05:39 PM »
Yes

The spacecraft was balanced for the cruise.  It spun for stability.
Since the entry vehicle was going to use a lifting entry, it needed to have an offset cg and so weights were ejected before entry.  However, JPL wanted to have a balanced vehicle for parachute deployment, so after entry more weights were ejected to bring the vehicle back into balance.

I get all that but I'm still having trouble understanding why 6 ballasts were needed...

Thanks for all the replies BTW.
Clayton Birchenough
Astro. Engineer and Computational Mathematics @ ERAU

Offline Jim

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Re: MSL Q&A
« Reply #222 on: 08/13/2013 05:41 PM »
Yes

The spacecraft was balanced for the cruise.  It spun for stability.
Since the entry vehicle was going to use a lifting entry, it needed to have an offset cg and so weights were ejected before entry.  However, JPL wanted to have a balanced vehicle for parachute deployment, so after entry more weights were ejected to bring the vehicle back into balance.

I get all that but I'm still having trouble understanding why 6 ballasts were needed...

Thanks for all the replies BTW.

To spread out the mass distribution and the attachment loading. 

Offline ClaytonBirchenough

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Re: MSL Q&A
« Reply #223 on: 08/13/2013 05:44 PM »
To spread out the mass distribution and the attachment loading. 

Ok, thanks.

Is there an image showing the two sets of ballasts by any chance? I searched but couldn't find any...  :-\
Clayton Birchenough
Astro. Engineer and Computational Mathematics @ ERAU

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