An Ultra-High-Altitude Sun-Synchronous Orbit and the Perturbation due to the Earth Gravity

Paper number

IAC-05-E2.1.02

Author

Ms. Keiko Kuroshima, University of Tokyo, Japan

Year

2005

Abstract

This paper presents a very high altitude, sun-synchronous orbit around the Earth. Usual sun-synchronous property derives from the perturbation due to the non-spherical Earth gravity field and is not usable for high altitude orbits. There is a great demand for astronomy satellites like infrared telescopes carrying cryo-coolers, for which the frozen orbital geometry between the sun and the Earth is favored and at the same time, the distance from the Earth surface should be enough far to avoid the albedo heat flux from it. And the contemporary infrared telescopes are sometimes placed in Halo orbits or heliocentric orbits that trail or lead the Earth as Spitzer telescope indicates. 
 What this paper presents first is an alternate solution to the requirements. Taking the advantage of associated characteristics with circular orbits under two-body motion, there exists a Cart Wheel orbit available around the Earth. It revolves around the Sun with slight eccentricity and also slight inclination and maintains the constant distance with respect to the Earth. Since the period of it is just one year, it is regarded as an ultra-high altitude sun-synchronous orbit, whose orbital plane is fixed perpendicular to the Sun-Earth line. If it is stable, as long as those orbital properties remain frozen, it is highly practical and can replace most of the above mentioned astronomy satellites orbits. (The idea belongs to the JAXA proprietary rights.)
 However, such interesting characteristics are unfortunately not frozen but significantly perturbed due to the Earth gravity field, in other words, under multi-body motion. It is evident that the altitude of it inevitably needs very high. Besides, the periods of both in-plane and out-of-plane motion vary each other and the trajectory becomes a Lissajous causing the nodal line moved around. 
 This paper analytically presents how much the nodal line longitude shifts and the results are compared and examined with those via numerical integration. The agreement is found quite well. The paper also analytically gives how much fuel is needed to keep the nominal Cart Wheel orbit properties retained. As easily expected, the fuel amount required decreases as the altitude increases. The paper concludes that the Cart Wheel trajectory around the Earth is regarded as a kind of sun-synchronous trajectory and is found highly practical with affordable correction velocity increment. 

Abstract document

IAC-05-E2.1.02.pdf

Manuscript document

IAC-05-E2.1.02.pdf (🔒 authorized access only).

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