Presentations text content in ASEN 6008
ASEN 6008Interplanetary Mission DesignSpring 2015Kate DavisLaunch Considerations
One of the most required aspects of an interplanetary mission design.Until we invent teleportation or master the control of an Einstein-Rosen bridgeFrom a mission design perspective, the primary three concerns we have for choosing a launch site:Availability / costPerformance (closer to the equator = more performance)Range of orbital inclinations / departure asymptotes that may be reached
Courtesy of NASA:
, A. B., Snyder, G. C., and
, R. A.,
Interplanetary Mission Design Handbook, Vol. 1, Part 2
Earth to Mars Ballistic Mission Opportunities, 1990-2005
, JPL Publication 82-43, 1983.Slide6
As you recall:The right ascension and declination of the launch may be computed from the outgoing v-infinity vector, departing Earth
RLA and DLASlide7
The Departing Hyperbolae
RLA and DLASlide8
The Departing HyperbolaeThere are an infinite number of options. Though not all are created equal.
RLA and DLASlide9
The Departing HyperbolaeOne constraint: Launch vehicles may target departure hyperbolae with inclinations less than or equal to the launch site latitude without suffering performance penalties.The minimum inclination of the departure hyperbolae is equal to the declination of the launch asymptote
RLA and DLASlide10
The Departing HyperbolaeQuestion: what coordinate frame are these vectors in?
RLA and DLASlide11
V is some value between -23.4 and +23.4 degrees, depending on the situation.Transformation from an ecliptic frame to an equatorial frame of reference.Earth’s obliquityDLAequatorial describes the minimum inclination of a parking orbit used.If the parking orbit has a smaller inclination, then there will be launch penalties.
RLA and DLASlide12
In addition to desired inclination, there is another HUGE factor to consider when launching.Allowable Launch AzimuthsLaunching over inhabited regions is generally frowned uponMost people wouldn’t want an SRB landing in their front yard.
Launch Range ConsiderationsSlide14
Launch Range ConsiderationsSlide15
Launch Range ConsiderationsSlide16
Launch Range ConsiderationsSlide17
Launch Range Considerations
Which azimuth yields the highest performance for a launch vehicle?
Question 2What is the resulting orbital inclination?
What is the range of DLA values that don’t suffer a penalty? (Equatorial)Slide18
Assume: Launch from Florida into 28.5
deg inclined LEO parking orbit.Observe: θ at rightIf you wanted to target an equatorial DLA of 0 degrees, where would you perform the Earth-departure maneuver?If you wanted to target an equatorial DLA of 28.5 deg, where would you perform the Earth-departure maneuver?
How do you target RLA?
Launch at the right time!Pay attention to your launch vehicle provider.
Can the upper stage re-light?
Does the system require staging orbits? How many?Slide20Slide21Slide22Slide23Slide24Slide25