Optical Navigation for Lunar Exploration Missions

Paper number

IAC-06-C1.7.05

Author

Dr. Markus Landgraf, European Space Agency (ESA), Germany

Coauthor

Dr. Gerhard Thiele, European Space Agency/EAC, Germany

Coauthor

Dr. Detlef Koschny, European Space Agency (ESA)/ESTEC, The Netherlands

Coauthor

Mr. Bogdan Udrea, European Space Agency (ESA)/ESTEC, The Netherlands

Year

2006

Abstract

The navigation on a lunar transfer trajectory is nominally achieved by
measuring the range and Doppler- shift of the telemetry link between
the spacecraft and the ground-station. For this reason the existence
of the link is mission critical and robotic missions fail when the
telemetry link is permanently lost, for example when the on-board
transceiver fails. For human missions, however, there is the
possibility to make use of the crew's capability of determining the
orbit by observing the apparent positions of the Moon and the Earth in
front of the star background. Here a method of manual orbit
determination for human lunar exploration missions is
presented. Optical navigation using measurements with a sextant
between landmarks and background stars has been tested by the Gemini,
and used by the Apollo Astronauts. In the Apollo missions, the use of
optical navigation was also used to determine the attitude of the
spacecraft prior to critical manoeuvres. Here we present a simpler
method that can easily be performed in an operational environment and
in an even more simplified version without the use of a computer:
measuring the time of occultation (eclipse) of stars by the Moon or
the Earth. From these measurements the crew can determine the amount
of dispersion of their spacecraft's state vector from the nominal
state either by using simple navigation algorithms on laptop computers
or lists of epochs tabulated before the mission. The analytical
sensitivity analysis shows that for example the periselenium altitude
can be determined with this method to better than 1km with a
measurement 24h before the periselenium arrival if the accuracy of the
measured time of occultation is equal or better than 1s. Examples for
the application of this navigation approach are presented for lunar
transfer and return trajectories as well as for Earth orbit. It is
proposed to demonstrate the operational feasibility of the method in
an experiment on board the International Space Station.

Abstract document

IAC-06-C1.7.05.pdf

Manuscript document

IAC-06-C1.7.05.pdf (🔒 authorized access only).

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