[X] My Assistant

[kwan3217]

Poking through the files at JPL NAIF, I found a couple of kernels for MSL. One is labeled cruise, and one is labeled EDL. Now since there is no target set yet, these are obviously preliminary, but they are still interesting for just seeing what EDL is like. this is the comment section of the EDL kernel:

MSL Sample EDL Trajectory SPK File (Central Landing Site (0.0 N, 45.0 E)
===========================================================================

Created by Fernando Abilleira, MSL MD/NAV. Comments added by
Boris Semenov, NAIF/JPL on Tue Feb 23 16:34:24 PST 2010.


Objects in the Ephemeris
--------------------------------------------------------

This file contains sample MSL (NAIF ID -76) EDL trajectory, from
atmospheric entry interface point to landing, for Type 1B, open of
launch period (11/25/2011), optimal launch time, central landing
site (0.0 N, 45.0 E), landing time 06-AUG-2012 11:35:46.7 UTC.

THIS FILE SHOULD BE USED FOR TESTING PURPOSES ONLY.


Approximate Time Coverage
--------------------------------------------------------

This file coverage is:

COVERAGE BEGIN TIME (TDB) COVERAGE END TIME (TDB)
------------------------- ------------------------
2012 AUG 06 11:30:58.537 2012 AUG 06 11:36:52.837


Pedigree
--------------------------------------------------------

This file was provided by Fernando Abilleira, MSL MD/NAV on
February 23, 2010. The original name of this file was
'day1_0.edlTraj.bsp'.


Contacts
--------------------------------------------------------

If you have any questions regarding this data contact

Boris V. Semenov, NAIF/JPL,
(818)-354-8136,
Boris.Semenov@jpl.nasa.gov

This particular kernel is just a list of positions and velocities at specific times, typically 0.1s apart. The attached CSV is a dump of the kernel at those times, plus some bonus stuff you can read about in the file.

And here it is:

 msl_edl.txt ( 566.51K ) Number of downloads: 1191

(Why can't I upload a CSV? Rename this to msl_edl.csv when you get it)


A couple of comments:
12 earth g's on entry! Phoenix peaked at 8.
It flies for a long time, starting to gain altitude at about 110s and not opening the chute until 250s

Of course I'll make an animation at some point, but I am actually more interested in this for analysis and backing out the aerodynamics model, so I can put it as a flyable model for Orbiter.

[kwan3217]

Something fun for those with Google Earth. Make sure you are on Mars and load this KMZ. It's my best current effort on an entry, descent, and landing dataset.

The entry state is the state at which Horizons says that the thing passes through 3522.2km distance from the center of Mars and 639.5km uprange of the target. I am landing about 12.2km downrange from the landing site, within the ellipse but only just barely. My code doesn't actually do any guidance, it just flies a reference trajectory I found described in one of the papers mentioned in the KMZ. A proper guidance system could surely land on the correct spot given this entry state.

My program does entry aerodynamics (with the heat shield) and descent aerodynamics (opening and riding the parachute) but does not yet separate and land. If you ride the tour, you will hit the ground at about 75m/s.

One of the fun things to do is to run a tour on the entry track. in Tools/Options/Touring, set the camera tilt to about 70deg, and the speed to 1.0. Then you can ride along with the vehicle.

I just noticed that entry tme is 5:11UTC, which will be 11:11pm MDT August 5 for me. It's a late night one, like the MER landers, not a mid-afternoon one like Phoenix.

Attached File(s)

 MSL_Entry_Simulation.kmz ( 9.63K ) Number of downloads: 423