Image:From Mission Concept to Mars Orbit.pdf

From Wikipedia, the free encyclopedia

Image
File history
File links

From_Mission_Concept_to_Mars_Orbit.pdf‎ File size: 232 KB, MIME type: application/pdf

[edit] Summary

Mars Express, ESA's first mission to orbit another planet, was launched on 2 June 2003 and arrived at Mars on 25 December 2003. Since orbit insertion it has successfully imaged more than 45% of Mars in infra-red and visible spectrums at resolutions of 10-100m/pixel, and returned extensive spectrometric science data for the planet’s atmosphere and surface, and Mars’ moon Phobos. The nominal mission ended November 2005 and a first extension will be completed end October 2007. Mars Express has also demonstrated data-relay capability for uplink/downlink to NASA MER rovers. The original mission operations concept was constrained partly by the resources available from a spacecraft designed within a very tight “flexi-class” mission budget. The major trade-off was between exploiting each pericenter pass for science, and the original concept of a single, daily, communications pass over the New Norcia ESA 35m deep-space antenna. An agreement was reached with NASA to provide pass-time on 34m and 70m antennas of the deep-space network, to provide additional downlink time and minimize pericenters lost for science. A fault in the power system, detected only after launch, left Mars Express limited to a maxi mum availability of 70% of design power for the entire mission. With long eclipses of up to 92 minutes and Mars aphelion power generation capability of less than 500W this generates a perpetual trade-off between support for the 65W X-band transmitter and science instrument operations. This paper seeks to examine the relationship between the mission operations concept and the operational flexibility that has been required to meet (and largely exceed) the mission objectives within the new envelope of constraints (power, downlink, fuel) and opportunities (additional ground stations, resources etc). The flexibilities provided by the original operations concept are identified and discussion is made of how these have been “stretched” to cope with the evolving mi ssion. Several aspects of the mission concept have been modified in light of flight experience. One significant change was the move from a “coverage” (mapping) science mission to a “target & coverage” science concept, based on improved knowledge of the mission's capabilities and on scientific opportunities foreseen by the science teams. Paradoxically this shift occurred at a time when the availability of three ground stations started to allow a full coverage over the nominal mission. Why these modifications have been made and the impact on the mission both in terms of cost and mission objectives is also discussed. The success of the Mars Express mission is largely to the flexibility provided by the original mission operations concept. This flexibility was partly enforced by the physics of Mars’ orbital missions (significantly eccentric solar orbit and relative distance to Earth ensuring significant variation on both power and data-downlink capabilities over the nominal mission), and partly due to rigorous and complex constraint checking at missionplanning level. Significant lessons can be learned from Mars Express in this respect; it is important to understand for any mission how the flexibilities provided by the operations concept could be used to cope with changes in system-level margins due to failures, anomalies or changes in the mission requirements late in the design stage or even in flight.

[edit] Licensing

This work is copyrighted and unlicensed. It does not fall into one of the blanket fair use categories listed at Wikipedia:Fair use#Images or Wikipedia:Fair use#Audio_clips. However, it is believed that the use of this work in the article "European Space Agency":

To illustrate the object in question
Where no free equivalent is available or could be created that would adequately give the same information
On the English-language Wikipedia ([1]), hosted on servers in the United States by the non-profit Wikimedia Foundation ([2]),

qualifies as fair use under United States copyright law. Any other uses of this image, on Wikipedia or elsewhere, may be copyright infringement. See Wikipedia:Fair use and Wikipedia:Copyrights.

To the uploader: this tag is not a sufficient claim of fair use. You must also include the source of the work, all available copyright information, and a detailed fair use rationale.

[edit] rational of fair use

   The paper linked here is claimed to be used under fair use as:
   # It is used to show an example of ESA's work.  
   # it is a scientific general puropose material
   # the paper is only being used for informational purposes.
   # Its inclusion in the article adds significantly to the article because

File history

Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version.
Click on date to download the file or see the image uploaded on that date.

(del) (cur) 16:14, 22 February 2007 . . Rusocer (Talk | contribs) . . 0×0 (238,043 bytes) (Mars Express, ESA's first mission to orbit another planet, was launched on 2 June 2003 and arrived at Mars on 25 December 2003. Since orbit insertion it has successfully imaged more than 45% of Mars in infra-red and visible spectrums at resolutions of 10-)