LAMBDA is a thematic data center focusing on serving cosmic microwave background (CMB) data to the research community. Data from the following missions are served: Wilkinson Microwave Anisotropy Probe (WMAP) COsmic Background Explorer (COBE) Infrared Astronomical Satellite (IRAS) Submillimeter Wave Astronomy Satellite (SWAS) CMB suborbital experiments. Community Requirements: CMB data is unlike other astrophysical data, consisting of: Intrinsically diffuse surface brightness photometry. Extremely faint signal levels: one part in 100,000 relative to the uniform background. Most users perform full sky analysis as opposed to partial sky or point source analysis. The nature of this data requires detailed knowledge of the instruments used in order to successfully use the data. The number of data sets in this field is not large; however, these data sets are becoming large and complex. This is a tendency that will increase as the polarization experiments currently being deployed begin producing data. WMAP Q-Band skymap, scaled from -200 to 200 µK from the 2.75K background Data is typically stored and supplied in FITS or ASCII format as appropriate. These are the standards for this type of data and therefore the most convenient for the users of the site. LAMBDA Staff: Gary Hinshaw (NASA, Director) Michael Greason (Adnet Systems) Britt Griswold (Infonetic) Paul Butterworth (Adnet Systems) Urmila Prasad (Adnet Systems) Janet Weiland (Adnet Systems) LAMBDA’s Implementation: Dell PowerEdge 4600, 2 Hyperthreaded 2.4GHz CPUs, 2GB RAM, 4.5TB disk space (configured as six RAID 5 filesystems). Backups: StorageTek SL-500 LTO-3 tape library using Legato Networker 7.3 (shared with WMAP) RedHat Enterprise Linux 4 ES Apache Web server ColdFusion 7 MySQL FTE’s The LAMBDA web site is constructed using the ColdFusion Markup Language (CFML), a scripting language. This confers several advantages: Consistent appearance and behavior across the entire site is maintained by consolidating formatting to a small collection of custom tags. Site maintenance is greatly simplified by this architecture. Development of new pages is greatly simplified. By encapsulating formatting into a set of tags, the author only needs to worry about individual page content. An easy to use database interface is built into the language, allowing the ready generation of dynamic pages. WMAP Product Web Page: The tables of data products may be collapsed and expanded to allow the user to make efficient use of screen real estate. It is generated from data in a MySQL database using a CFML custom tag; the page simply supplies arguments to the tag to select output. This page is representative of the data product listings and of the data download pages Analysis Tools: LAMBDA has developed several tools for the CMB community; it also provides links to a collection of tools developed by other research groups. A contributed software archive has also been opened (and is served from a web site at JHU) that facilitates the sharing of tools between members of the community. Screen shot of LAMBDA’s skyviewer tool. This tool permits viewing of HEALPix- formatted skymaps on a 3D sphere or in a Mollweide projection. LAMBDA’s strengths: It is a small, focused data center catering to a specific segment of the astronomical community. The specific needs of this important area of research are readily targeted, and changes in needs can be quickly adapted to. It is run by and has easy access to many of the leading researchers in the field of cosmology. It has a simple, easy to navigate design that can be readily modified as needs change. Some Problems: SPAM! An archive of questions received and responses is maintained; in the last few months, a flood of spam has necessitated the addition of a filter. Acquisition of data from small project scientists. Convincing scientists to allow their data (as opposed to simply the results) to be served is frequently difficult. In terms of manpower, LAMBDA is quite small. This isn’t a problem when dealing with day-to-day operations and maintenance; nor is it a problem during data ingest. However, it can make it difficult to deal with requirements imposed from outside. Science Archives in the 21 st Century: NASA’s Legacy Archive for Microwave Background Data Analysis (LAMBDA) Paul Butterworth, Adnet Systems Inc., Code 665, NASA/GSFC, Greenbelt, MD (301) ,