MSL Cruise Phase Options

[nprev]

Okay, we're off and running! Please post all comments relating to MSL's transit to Mars here.

[djellison]

Also VERY cool would be any MAHLI picture from inside of the spacecraft during the cruise phase ... as was done with Phoenix RAC camera.
Do we know if MSL team has intention to do such a test shot?

Don't know if they plan to - but I would have thought they would... inflight-cal is a useful post-launch checkout. I wouldn't expect them to actuate the lens cover - but they could certainly power up the white-light LED's and take a picture inside the backshell. It would, I think, show the steering actuator for the front left wheel in its stowed position.

Is the cruise stage's spin in real-time?
Great attention to detail if so!

No - it's canned at 2rpm ( the nominal cruise spin rate) Remember, 'Eyes...' uses a combination of predicted and reconstructed data. Getting 'live' data thru from a flight project in these ITAR laden times is a mountain that even I'm not even going to attempt.

I am not sure how accurate the model is but it looks like there is only one thruster jet on the cruise stage for course corrections, I would have thought 2 would be more reliable.

Using this image as reference:
http://www.jpl.nasa.gov/images/msl/20111110/pia15026-43.jpg

Assuming you meant the thruster at about 5 O'clock...that's not a thruster you're looking at. That's the star-tracker.

There are 8 thrusters - two clusters of 4. In that image they are at about 1 O'clock and 7 O'clock, covered with a red remove before flight fixture. They're tiny.

Could you provide a link ? I think Doug mentioned this before. I've only read that MAHLI would do time-lapse type frames...

If you google MAHLI. The very first link takes you to the MSSS page that includes a link to 'reference material'.
Documents like this : http://www.msss.com/msl/mahli/references/E...l_MarsMicro.pdf : and this : http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1197.pdf should fill you in. I've heard annecdotal comments that using MAHLI for DD surveys is possible, as it's the widest FOV camera (apart from MARDI, which obviously isn't going to be looking for DD's) with the movie ability. Mastcam 34 is roughly Pancam FOV, and Mastcam 100 about 1/3rd of that - whereas MAHLI is, if my math is right - about 30 x 23 deg FOV. The question would be - is it worth the large energy spend to move the arm into an elevated position for such a survey. It's not something I'd expect to see happening early on, that's for sure.

D

[MarsEngineer]

There are 8 thrusters - two clusters of 4. In that image they are at about 1 O'clock and 7 O'clock, covered with a red remove before flight fixture. They're tiny.

D

Doug has it right. The two thruster clusters on either side of the cruise stage used by MSL are nearly exactly the same used on Mars Pathfinder and MER.

Each thruster can provide about a pound of push when needed. This configuration is very handy (if I do say so myself ) for doing "balanced" turns(*) that do not impart unwanted changes in the trajectory. Considering MSL is so big compared with these other mars missions, it is amazing that these little thrusters are all we need to keep the solar arrays pointed roughly to the sun and the antennas roughly toward the Earth. It is even more amazing that they can also refine MSL's flight path to stay on course (obviously MSL's TCMs take more time to accelerate the same amount as MER or MPF because MSL is several times more massive).

* we use the word "turn" to denote a rotation of the vehicle, not a left or right turn of the flight path. The latter we call TCMs - trajectory correction maneuvers.

-Rob

PS Doug, Nice tool!!!!!