Dear Colleague,

NASA is pleased to call to the attention of members of the U.S. 
scientific community the release by the European Space Agency (ESA) 
of the Announcement of Opportunity (AO), "XMM-Newton Call for 
Observing Proposals", soliciting Guest Observing proposals for the 
fifth cycle (AO-5) observing program for ESA's X-ray Multi-Mirror 
Mission (XMM-Newton).  The subject Announcement solicits proposals 
for observations to be performed during a 12-month period commencing 
in May 2006.  Due to the nature of the NASA-ESA bilateral agreement, 
proposals from scientists affiliated with U.S. institutions only are 
solicited by this Letter; others are advised to contact ESA directly. 
U.S. scientists may propose either as Principal Investigators or as 
Co-Investigators on proposals with non-U.S. P.I.'s (foreign P.I. 
proposals). The AO may be accessed directly from ESA at the following 
address:

http://xmm.vilspa.esa.es/external/xmm_science/AO5/

The XMM-Newton Guest Observer Facility (GOF) at the Goddard Space 
Flight Center (GSFC) is the support center for XMM-Newton activities 
in the U.S.  Information of interest to U.S. observers, as well as 
general project information, can be found at the following address:

http://xmm.gsfc.nasa.gov/

A detailed description of the mission, including instrument 
capabilities and additional information pertaining to the proposal 
preparation and submission procedures, is also available via links 
from the XMM-Newton home page at that address.  (General questions 
concerning XMM-Newton and participation by U.S. investigators should be 
addressed to xmmhelp@athena.gsfc.nasa.gov.)  ESA will be responsible 
for conducting a peer review of all submitted proposals, including 
those from U.S. investigators, and determining the associated time 
allocation.  Current plans call for ESA to notify proposers and NASA 
of the results of the peer review in early January 2006.

As for Cycles 1-4, NASA has allocated funding for a Guest Observer 
(GO) program to support the analysis, interpretation, and publication 
of data obtained by U.S. proposers who are granted Open Time observing 
on XMM-Newton through the ESA AO. The level of funding available for 
any approved program will depend on the total funding available, the 
size and complexity of the investigation, whether the proposed budget 
is for a P.I. or lead Co.-I. (for foreign PI proposals), on the 
ultimate number of U.S. investigations approved by ESA, and possibly
on other factors.  Note that higher priority is assigned to U.S. 
P.I. proposals; funding for Co-I. participation in foreign-P.I. 
proposals is allocated at a reduced level (roughly one-half of the 
U.S. P.I. level for an equivalent proposal, an increase over previous 
AOs granted by the 2004 Senior Review).  We anticipate that 
approximately $5 M will be available for support of U.S. Guest 
Observers under AO-5.  Details regarding the timing and mechanism of 
NASA's solicitation for data analysis funding requests will be 
announced after the results of the ESA peer review have been released; 
please do not submit a budget with your observing proposal.

For additional technical or programmatic information regarding U.S. 
participation in the XMM-Newton mission, please contact:


Technical Information:          Dr. Steve Snowden 
                                Goddard Space Flight Center 
                                Code 662 
                                Greenbelt, MD  20771 
                                Tel:  (301) 286-8100 
                                Fax:  (301) 286-1684 
                                snowden@milkyway.gsfc.nasa.gov 

Programmatic Information:       Dr. Wilton Sanders 
                                Universe Division
                                Science Mission Directorate
                                NASA Headquarters

                                Washington, DC  20546
                                Tel:  (202) 358-1319
                                Fax:  (202) 358-3096
                                Wilton.T.Sanders@nasa.gov

Sincerely,

Dr. W. T. Sanders
US XMM-Newton Program Scientist