Subject: Discussion on GG at JPL From: Anna Nobili Date: Mon, 13 Sep 2010 01:09:09 +0200 To: "Slava G. Turyshev" CC: Michael Shao , Alberto Anselmi Dear Slava, In a message you sent me today on another subject, which I read at about midnight, you write: “Tomorrow we will have our review at JPL at which will decided on whether or not JPL will invest in our Explorer proposal. Mike and I will have 2 hours to discuss all the possible scenarios. Could you send me some material that would cover the following areas: 1. Science 2. Experimental concept 3. Instrument design 4. Mission design 5. Cost It would be nice to have idea what can be done at TAS-I? Can we ask for drag free spacecraft similar to GOCE? (By the way what are the drag free requirements?) What total amount of likely Italian contribution can we discuss? Is it 30 or 40 M euros? How and when this can be decided? I am making presentation using some pdf documents from previous workshop. However, not all the documents are available (i.e., presentation made by Alberto, for instance)... Slava” I am quite worried because there is no way I can prepare for you in such a short time a good presentation for the meeting, which on the other hand is very important. However, I can try to give you some material - I cannot send it by email – too big; I am uploading it on the GG webpage at the following address http://eotvos.dm.unipi.it/temp/ForSlava12Sept2010/ so, go there and download the files you will find. I would start with the presentations by Alberto (Synthesis of GG Study) and Gisueppe (error budget) at our February workshop . PDF files are on the webpage http://eotvos.dm.unipi.it/Workshop2010/index.html You will find the corresponding PPT files on the address above (the ppt file of Alberto’s talk is damaged but I have the one he gave in Rome at ASI on June 21 2009 when you came) The full ppt file with all presentations given by TAS-I on June 18 2009 at the final meeting TASI GG Final Presentation 090618_master.ppt contains in particular the presentation of GG drag free control (by Gianfranco Sechi, starting at slide 43). Concerning drag free control, I have sent you (my email of July 2009) a summary of the requirements GG thruster requirements @ 1 Hz.pdf It is taken from the full document by Sechi, which I have also sent you by email on July 30 FromScientificRequirementsToDFCRequirements.pdf You can use as a summary report of the study (to help you in going through the slides) the printed one (with the nice cover by Alice) available in PDF at http://eotvos.dm.unipi.it/PA2/index.html As a nice recent general presentation (including results from GGG), I upload the GG presentation I gave at the GPhys Colloquium in Paris at the end of June TalkGPhys2010.ppt The total cost, as you know is 70 ME (excluding launch) You ask: “Can we ask for drag free spacecraft similar to GOCE?” Be VERY CAREFUL: the GG spacecraft is ad hoc and has nothing to do with GOCE spacecraft (which was far more expensive…). You can say that the drag free control of GG has been designed by the same people who designed the DFC of GOCE (the key person is Gianfranco Sechi), hence expertise accumulated with GOCE is available for GG Concerning what can be done at TAS-I, I would say: DFC, thermal control, spacecraft “spinning top” in carbon fiber (involving the small company from Ferrari), payload assembly As for ASI contribution, I think that we should make the exercise Mike described in his message of July 30; and then ask ASI and see how much it is prepared to fund, and that should be put down in a letter signed by the President. I think if we submit GG to EXPLORER for 100 M$ (not 200) and manage to convince ASI to put up to 30 ME, plus FEEPs from ESA, that would make GG quite competitive. However, please be aware that 30 ME from ASI might be too much; I do not know at present Ciao Anna *********************************************************************** Anna M Nobili tel +39 050 2214632 Dipartimento di Fisica "E. Fermi" mobile +39 347 2522634 Universita' di Pisa Largo Bruno Pontecorvo 3 I-56127 Pisa, Italia nobili@dm.unipi.it LABORATORY: INFN, Sezione di Pisa(San Piero a Grado) Via Livornese 1291 I-56010 San Piero a Grado, Pisa tel +39 050 2210408 "Galileo Galilei" (GG) Project and "GG on the Ground" (GGG experiment) webpage http://eotvos.dm.unipi.it Anna Nobili homepage: http://eotvos.dm.unipi.it/homenobili.html ***********************************************************************