The Lunette Space Mission: Using a Nanosatellite for High Resolution Mapping of the Far-Side Lunar Gravity Field
- Paper number
IAC-07-B4.2.03
- Author
Mr. Benoit Larouche, University of Toronto Institute for Aerospace Studies, Canada
- Coauthor
Dr. Robert E. Zee, University of Toronto, Canada
- Coauthor
Mr. Henry Spencer, University of Toronto Institute for Aerospace Studies, Canada
- Coauthor
Prof. Jafar Arkani-Hamed, University of Toronto, Canada
- Year
2007
- Abstract
Understanding the Moon’s gravity field is important for navigation in support of future lunar missions and also for accurate topographical mapping and mineral exploration. Near side gravity maps have resolutions to about 10-20 mGal due to the ability to perform ranging measurements from Earth as a lunar orbiter passes over the near side. The far side gravity field has so far been inferred through model fitting based on observations from Earth of entry and exit as lunar orbiters pass over the far side and can be 5-10 times worst. The far side gravity model could be refined significantly; if two low altitude satellites were to measure relative range rate over the far side of the Moon. This is the basis of the Lunette mission, a low-cost approach to high resolution lunar gravity mapping through the use of nanosatellite technology, currently the subject of a Phase A study at the Space Flight Laboratory (SFL). Lunette has been selected as a payload for the European Student Moon Orbiter (ESMO) project under the Student Space Exploration and Technology Initiative (SSETI) programme of the European Space Agency’s Education Department in ESTEC. The Lunette concept is a 7 kg payload, including a 6 kg “nanosatellite” that will separate from ESMO in Lunar orbit, and a 1 kg radio-tracking payload that will remain on the parent satellite. The nanosatellite will include a propulsion system, with a 100m/s ΔV capability, along with a high-performance attitude control system with 1.5 arc-minute pointing stability. The propulsion system provides active formation flying, increasing the orbital life of the nanosatellite and permitting alterations to its orbit to improve science data. The attitude-control system permits accurate maneuvers and prevents contamination of the range-rate data by satellite rotations. The main scientific aim of the Lunette mission will be accomplished by collecting the relative speed between ESMO and the deployed nanosatellite. Lunette will carry an S-band coherent radio transponder, and the stay-behind electronics package will have a tracking beacon, a receiver, and a return-signal analyzer. The beacon will transmit a tracking signal, which the transponder on the nanosatellite will receive, and re-transmit. The re-transmitted signal will be received and analyzed to measure the 2-way Doppler shift, from which the range rate between the two satellites can be inferred. Preliminary analysis suggests that using existing and SFL-developed equipment in a 100km circular orbit can achieve a full-globe precision of at least 20mGal, comparable to the nearside quality of the LP75G map released at the end of the Lunar Prospector primary mission. A reliable global map of this precision would be a major scientific accomplishment, rendering all other lunar gravity maps obsolete.
- Abstract document
- Manuscript document
IAC-07-B4.2.03.pdf (🔒 authorized access only).
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