Data Analysis on Contour Probe

Marisa BrionesMilton Diaz

Maurice Fernandez

Danny Gunawan

Project

• Overview on Contour Probe

• Compute the distances of the perigee andapogee to the center of the earth

• Simulate trajectory of the probe

• Design a sequence of speed changes in theapogee and perigee which will result in acircular orbit of radius 100,000 km.

NASA’s Contour ProbeTo explore the nucleus of two, possibly

three comets.

Mission

Probe and Comet

Contour Probe

Four scientific instruments will take images and spectral maps ofthe nucleus of comets and analyse the surrounding gas and dust,

providing the most detailed data on these mysterious, dynamic, andancient keepers of the solar systems original material.

INSTRUMENTS

Contour Remote Imaging Spectrograph(CRISP)

Contour Forward Imager (CFI)

The Neutral Gas and Ion Mass Spectrometer willmeasure the abundance and isotope ratios for

many neutral and ion species in the coma of eachcomet during the flyby

The Neutral Gas and Ion Mass Spectrometer

Contour Dust Analyzer (CIDA)

Contour Dust Analyzer (CIDA)

The mission plan called for the probe tomeet up with comet Encke in 2003,

Schwassman-Wachmann 3 in 2006 andperhaps comet d'Arrest in 2008.

• Launch: July 3, 2002 at 2:27 a.m. EDT

Lost Aug. 15, 2002

Scientists believe this picture showsContour broken in two pieces

Equations

• 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 velocityv=(2GM/r)^.5 wherer=100,000km

CalculationsUsing the orbital elements we calculated the following in

1,000km/1,000s:

• T=150s

• M=6.2262rad

• E=5.8603

• f=4.8213

• r=11.365km

• p=1.2466km

• h=70491km

• e = 0.8915936

• x=.81547km

• y=9.8432km

• z=-5.6222km

• vx=-6.519km/s

• vy=-4.2446km/s

• vz=1.7541km/s

Apogee & Perigee

• 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 ContourProbe.

• We used the original x, y, z values and velocityvalues to simulate an orbit but the software did notproduce 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(1-e^2))^.5*(1+e)

• x=-115 km Vx=0

• y=0 Vy=-0.33825 km/s

• z=0 Vz=0

Sequence of Speed Changes• 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 by97.2% because the absolute values were largerthan the escape velocity of the earth, which is7.9km/s: vx=0.15739 km/s vy=0.15838 km/s

• At the apogee we increased the velocity through asequence of speed changes to create new perigeesand apogees until the ellipse had a radius of100,000 km.

Sequences

• vx=0.01km/s

• vy=-0.4km/s

• We tripled the initialvalues:

• 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 gavethe absolute values ofx and y to equal to aradius of 100,000 km.

Vx = -0.0484Vy = 0.02488

Circular Orbit of Radius 100,000 km

• When we reached an ellipse with theabsolute value of x and y equal to 100,000km, we tried to create a circular orbit withthis radius. The final velocity according tothe equation: v=(2GM/100)^.5 is 0.089286km/s.

• We took the absolute value of v x and vy anddivided the final velocity by this value toget k=1.63972.

Final Values

• x= -87.2773528989 km

• y=-50.5478705216 km

• By trial and error: v x= -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 trueorbit.

• Through a sequence of speed changes, acircular orbit of radius 100,000 km can besimulated, but still problems with thesoftware do not produce the correctsimulation.

Acknowledgments

• Dr. Horn

• Dr. Varadi

• Dr. Shubin