Data Analysis on Contour Probe
Marisa Briones
Milton Diaz
Maurice Fernandez
Danny Gunawan
Project
• Overview on Contour Probe
• Compute the distances of the perigee and
apogee to the center of the earth
• Simulate trajectory of the probe
• Design a sequence of speed changes in the
apogee and perigee which will result in a
circular orbit of radius 100,000 km.
Mission
NASA’s Contour Probe
To explore the nucleus of two, possibly
three comets.
Probe and Comet
Contour Probe
INSTRUMENTS
Four scientific instruments will take images and spectral maps of
the nucleus of comets and analyse the surrounding gas and dust,
providing the most detailed data on these mysterious, dynamic, and
ancient keepers of the solar systems original material.
Contour Remote Imaging Spectrograph
(CRISP)
Contour Forward Imager (CFI)
The Neutral Gas and Ion Mass Spectrometer
The Neutral Gas and Ion Mass Spectrometer will
measure the abundance and isotope ratios for
many neutral and ion species in the coma of each
comet during the flyby
Contour Dust Analyzer (CIDA)
Contour Dust Analyzer (CIDA)
The mission plan called for the probe to
meet up with comet Encke in 2003,
Schwassman-Wachmann 3 in 2006 and
perhaps comet d'Arrest in 2008.
• Launch: July 3, 2002 at 2:27 a.m. EDT
Lost Aug. 15, 2002
Scientists believe this picture shows
Contour broken in two pieces
Equations
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x=rcosf
y=rsinf
h=(GMa(1-e^2))^.5
p=a(1-e^2)
r=p/(1+e)
x*=(-h/p)sinf
y*=(h/p)(e+cosf)
r=(x^2+y^2)^.5
• v=(vx^2+vy^2)^.5
• v=(GM/a(1-e^2))^.5
*(1+e^2+2ecosf)^.5
• at apogee f = 180
• at perigee f = 0
• final velocity
v=(2GM/r)^.5 where
r=100,000km
Calculations
Using the orbital elements we calculated the following in
1,000km/1,000s:
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T=150s
M=6.2262rad
E=5.8603
f=4.8213
r=11.365km
p=1.2466km
h=70491km
e = 0.8915936
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x=.81547km
y=9.8432km
z=-5.6222km
vx=-6.519km/s
vy=-4.2446km/s
vz=1.7541km/s
Apogee & Perigee
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apogee=p/(1-e)=115km
perigee=p/(1+e)=6.5902km
distances to the center of the earth:
apogee - radius of earth = 115km - 6.378km
= 108.6 km
• perigee - radius of earth = 6.5902km 6.378km = .212 km
Orbital Simulation
• Using Dr. Varadi’s Orbital Simulation Software
we investigated the trajectory of the Contour
Probe.
• We used the original x, y, z values and velocity
values to simulate an orbit but the software did not
produce an orbit.
• We set y, z, vx, vz equal to 0 and the values for x
& y equal to: x=apogee & Vy=v=(GM/a(1e^2))^.5*(1+e)
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x=-115 km
y=0
Vx=0
Vy=-0.33825 km/s
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z=0
Vz=0
Sequence of Speed Changes
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We used the planar values for x, y, z, vx, vy, vz.
x=1.2353km y=11.298 km z=0
vx=5.6212 km/s vy=5.6563 km/s vz=0
We decreased the planar values for vx & vy by
97.2% because the absolute values were larger
than the escape velocity of the earth, which is
7.9km/s: vx=0.15739 km/s vy=0.15838 km/s
• At the apogee we increased the velocity through a
sequence of speed changes to create new perigees
and apogees until the ellipse had a radius of
100,000 km.
Sequences
• vx=0.01km/s
• vy=-0.4km/s
• We tripled the initial
values:
• vx=0.03km/s
• vy=-0.12km/s
• We did a 25% increase:
• vx=0.0325km/s
• vy=-0.13km/s
• We did a 0.65%
decrease:
• vx=0.032435km/s
• vy=-0.1274km/s
• These velocities gave
the absolute values of
x and y to equal to a
radius of 100,000 km.
Vx = -0.0484
Vy = 0.02488
Circular Orbit of Radius 100,000 km
• When we reached an ellipse with the
absolute value of x and y equal to 100,000
km, we tried to create a circular orbit with
this radius. The final velocity according to
the equation: v=(2GM/100)^.5 is 0.089286
km/s.
• We took the absolute value of v x and vy and
divided the final velocity by this value to
get k=1.63972.
Final Values
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x= -87.2773528989 km
y=-50.5478705216 km
By trial and error: vx= -0.037164 km/s
By k * vy: vy=0.04081 km/s
Conclusion
• The contour probe was lost August 15,
2002.
• From its orbital elements, there was no true
orbit.
• Through a sequence of speed changes, a
circular orbit of radius 100,000 km can be
simulated, but still problems with the
software do not produce the correct
simulation.
Acknowledgments
• Dr. Horn
• Dr. Varadi
• Dr. Shubin