Cassini-Huygens Maneuver Experience: Ending the Prime Mission

Goodson, Troy; Ballard, Christopher G.; Gist, Emily M.; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, P.

doi:10.2514/6.2008-6751

Cited by 8 publications

(7 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is a postencounter solution, which shows the actual encounter position in the B plane. For this cleanup maneuver contour plot example, using the 071120_053T38 (short) solution shows that the cost to cancel OTM134 [7] is approximately 0:7 m=s. This was in very close agreement with the integrated solution, which produced a value of approximately 0:8 m=s OTM134 cancellation cost.…”

Section: B Cleanup Maneuver Cancellation Contour Plotmentioning

confidence: 98%

Flyby Error Analysis Based on Contour Plots for Cassini Tour

Stumpf

Gist

Goodson

et al. 2009

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

The maneuver cancellation analysis consists of cost contour plots employed by the Cassini maneuver team. The plots are two-dimensional linear representations of a larger six-dimensional solution to a multimaneuver, multiencounter mission at Saturn. This realization and the use of the tool itself is just one of the many significant engineering achievements that have come from the Cassini project. After inserting the cost contour capability with an enhancement (taking account of asymptote changes), a tool that was originally only used for analysis could be used for operations once the accuracy of the plots was determined to be acceptable for operations. The plots have been used extensively since the enhancement. By using contours plotted in the B plane with B R and B T components, it is possible to view the effects on V for various encounter positions in the B plane. The plot is used in operations to help determine if the approach maneuver (ensuing encounter minus three days) and/or the cleanup maneuver (ensuing encounter plus three days) can be cancelled and is a linear check of an integrated solution. The plots have also been used to bias the targets of encounters to save V. Nomenclature B = B vector or B plane B R = vertical axis of the B plane B T = horizontal axis of the B plane C3 = excess velocity or characteristic energy G x;y = grid point value on the contour plot for an approach maneuver, m=s G x;y;c = grid point value on the contour plot for a cleanup maneuver, m=s i = leg index J x;y = V calculation of a B plane grid point for an approach maneuver, m=s J x;y;c = V calculation of a B plane grid point for a cleanup maneuver, m=s K = K matrix, a maneuver capability matrix M = the B plane mapping R = R vector of the B plane r o = nominal trajectory apoapsis maneuver location S = the incoming asymptote T = T vector of the B plane T n = nth encounter of Titan V1 = the magnitude of the velocity for a cleanup maneuver, m=s V2 = the velocity magnitude for an apoapsis maneuver, m=s B A = asymptote change B plane state vector B RT = grid variation vector B xy = the variations in the B plane with a perturbed trajectory B R y = y component of grid points in the B plane B T x = x component of grid points in the B plane r = difference in the apoapsis maneuver location for a perturbed trajectory V = change in velocity, m=s V REF = change in velocity given in the reference trajectory, m=s

show abstract

Section: B Cleanup Maneuver Cancellation Contour Plotmentioning

confidence: 98%

Flyby Error Analysis Based on Contour Plots for Cassini Tour

Stumpf

Gist

Goodson

et al. 2009

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

show abstract

“…Equation (10) can be rewritten in terms of the semimajor axis and the semilatus rectum by substitution of Eqs. (11)(12)(13):…”

Section: (9)mentioning

confidence: 99%

“…Goodson et al [28], Standley [29], and Wagner et al [30] describe the engineering operations and maneuver experience during the mission. The Cassini primary mission ended in July 2008 [11], with an extended mission planned until June 2010 [12].…”

Section: Background Of the Cassini-huygens Missionmentioning

confidence: 99%

“…Titan, being the most massive moon of Saturn, serves as the most effective gravity-assist body in the Saturnian system. Since its arrival at Saturn in July 2004, Cassini has performed over 40 flybys at Titan in its primary mission, which was completed in July 2008 [7][8][9][10][11]. Up to a total of 70 Titan flybys have been planned for its extended mission through June 2010 [12].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Saturn Impact Trajectories for Cassini End-of-Mission

Yam

Davis

Longuski

et al. 2009

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

Potential end-of-mission scenarios to be considered for the Cassini spacecraft must satisfy planetary quarantine requirements designed to prevent contamination of a pristine environment, which could include Titan and the other Saturnian moons. One assumed acceptable option for safe disposal of the spacecraft includes Saturn impact trajectories. Two classes of impact trajectories are investigated: short-period orbits characterized by periods of 6-10 days and long-period orbits with periods greater than 850 days. To impact Saturn with short-period orbits, a series of successive Titan flybys is required to increase inclination and decrease periapsis to within Saturn's atmosphere, while simultaneously avoiding the rings and mitigating V expenditures. To ensure that the spacecraft is not prematurely damaged by material in the rings, Tisserand graphs are employed to determine when the ring-plane crossing distance is within the F-G ring gap: the necessary geometry for the penultimate transfer. For long-period impact trajectories, solar gravity is exploited to significantly lower periapsis. Depending on the size and orientation of the long-period orbit, a maneuver (<50 m=s) at apoapsis must be added to ensure impact. For sufficiently large orbits with favorable characteristics, solar gravity alone drops the spacecraft's periapsis into Saturn's atmosphere. No maneuver is necessary after the final Titan flyby, providing an attractive "flyby-and-forget" option. Nomenclature a = semimajor axis, km or R S e = eccentricity h = specific angular momentum, km 2 =s h p = flyby altitude, km i rel = inclination relative to the gravity-assist body's orbit, deg J 2 = Saturn's oblateness coefficient m = number of gravity-assist body orbits about the central body n = number of spacecraft orbits about the central body p = semilatus rectum, km or R S R S = Saturn's radius, km (R S 60; 268 km) R T = Titan's radius, km (R T 2575 km) r = position vector from the central body, km or R S r = radial distance from center of Saturn to spacecraft, km or R S r a = radius of apoapsis from central body, km or R S r enc = radial distance of encounter from central body, km or R S r p = radius of periapsis from central body, km or R S r vac = radial distance of vacant node from central body, km or R S T = orbital period, day V = velocity vector relative to the central body, km=s V 1 = hyperbolic excess velocity vector, km=s v = velocity magnitude relative to the central body, km=s v 1 = hyperbolic excess velocity magnitude, km=s = pump angle, deg = flight-path angle, deg V = change in velocity magnitude, km=s = flyby bending angle, deg = flyby B-plane angle, deg = crank angle, deg = gravitational parameter, km 3 =s 2 = orientation of the spacecraft orbit relative to the sunSaturn line, deg Subscripts ga = quantity for the gravity-assist body sc = quantity for the spacecraft

show abstract

“…As depicted in the figure, the Cassini spacecraft made several flybys of Saturn's largest moon Titan to maintain the orbit, and flybys of other icy satellites such as Enceladus, Tethys, Hyperion, Dione, and Rhea. 7,8,9,10 After the Cassini spacecraft achieved its flyby milestones during the Prime Mission, adjustments to the reference trajectory were made to incorporate ephemeris updates and design changes based on the science discoveries. Table 1 lists the corresponding trajectory updates for each phase of the mission.…”

Section: Introductionmentioning

confidence: 99%

Updating the Reference Trajectory for the Cassini Solstice Mission

Valerino

2014

SpaceOps 2014 Conference

View full text Add to dashboard Cite

The Cassini-Huygens deep-space probe has successfully completed a four-year prime tour and a two-year extended tour of the Saturnian system. Now in a second extended phase called the Solstice Mission, the Cassini spacecraft will continue to gather data as directed by the reference trajectory until 2017. This paper describes the process of how a reference trajectory update is prepared and delivered to the Cassini Project by the navigation team during Solstice Mission flight operations. This paper also documents the timeline of products released and utilized, as well as the study to include an Enceladus occultation observation that occurs in 2016.

show abstract

Cassini-Huygens Maneuver Experience: Ending the Prime Mission

Cited by 8 publications

References 6 publications

Flyby Error Analysis Based on Contour Plots for Cassini Tour

Flyby Error Analysis Based on Contour Plots for Cassini Tour

Saturn Impact Trajectories for Cassini End-of-Mission

Updating the Reference Trajectory for the Cassini Solstice Mission

Contact Info

Product

Resources

About