Status Report

NASA Request for Information for Medium Sun Sensors for the Global Precipitation Measurement Core Observatory

By SpaceRef Editor
June 26, 2008
Filed under , ,

Synopsis – Jun 25, 2008

General Information

Solicitation Number: RFI-GPM-Medium-Sun-Sensors
Posted Date: Jun 25, 2008
FedBizOpps Posted Date: Jun 25, 2008
Original Response Date: Jul 24, 2008
Current Response Date: Jul 24, 2008
Classification Code: A — Research and Development
NAICS Code: 334511 – Search, Detection, Navigation, Guidance, Aeronautical, and Nautical System and Instrument Manufacturing

Contracting Office Address

NASA/Goddard Space Flight Center, Code 210.Y, Greenbelt, MD 20771


This notice is issued by the NASA/GSFC to post a Request for Information via the internet to seek industry comments and input regarding the availability of Medium Sun Sensors (MSS) for the Global Precipitation Measurement (GPM) Core Observatory attitude control system. This document is for information and planning purposes and to allow industry the opportunity to verify reasonableness and feasibility of the requirements, as well as promote competition.

The GPM mission is one of the next generation satellite-based Earth science constellation missions that will study global precipitation (rain, snow and ice). GPM Core Observatory will be carrying both a dual frequency radar instrument and a passive microwave radiometer. The Core Observatory will serve as a calibration standard for the other members of the GPM constellation. The mission life requirement of GPM is 3 years, with the goal of 5 years.

GPM is a scientific observatory, carrying instruments designed to characterize the precipitation over the globe on a continuous basis. Scientists must control, very precisely, where each instrument on the observatory is pointing so that data can be geo-located for future analysis. As the instruments’ fields-of-view move from target to target, knowledge of where data was taken must be accurately recorded as the observatory moves through space.

The Medium Sun Sensor may be packaged in a single housing or as multiple sensor heads affixed to a mounting structure, where the mounting structure interfaces with the spacecraft. The MSS will be used to determine the position of the sun in the local x-y coordinate plane, which is the plane orthogonal to the MSS mounting surface.

In order for GPM to comply with NASA’s end-of-life disposal requirements in the most efficient manner, the Core Observatory will be designed to demise (burn up or melt away) upon atmospheric re-entry to the greatest extent possible. The debris casualty area allocated to the MSS is 0 m2, meaning that the MSS are required to completely demise during re-entry. This is not expected to be an issue with a component the size of the MSS, but it must be examined.

The GPM Project is planning an acquisition strategy for two flight MSS. Some fundamental information is requested from industry to assist the GPM project with the development of an acquisition strategy for the MSS. Through this RFI, the GPM Project wishes to identify MSS requiring none to minimal non-recurring engineering (NRE) costs that will meet the GPM observatory performance needs and satisfy the total demiseability guidelines for the GPM mission.

The following are requirements for the MSS:

Description Requirement Accuracy +/- 2 degrees (per axis, 3 sigma) Field of View (half cone angle) 17.5 degrees Tolerance: +/- 2.5 degrees Power 0W(1) Temperature Range (operating)-40*C to +93*C Mass (including all brackets and baffles)<500 g Size (including all brackets and baffles)Fits within 5x5x5 inch cube 1 - MSS is to be a current source only with no external power required.

With regard to alignment: the MSS sensors will require placement, knowledge and stability tolerances of +/- 0.2 degrees each. An alignment cube, with surfaces normal to less than 5 arcsec, will be used for MSS alignment to the spacecraft. It is desirable to have the alignment cube delivered as part of the MSS. If it cannot be, the spacecraft may be able to provide an alignment cube on the MSS mounting bracket.

The GPM Project encourages all industry sources with expertise in providing sun sensors to respond to this RFI. The responses should demonstrate technical feasibility, operational robustness and reliability. Sources with relevant information to this RFI are encouraged to respond by submitting a white paper that includes the following information:

Background and Description of Proposed Approach: Describe in detail the specific components being proposed for GPM Project’s consideration. Describe the current state of development, past use, types of interfaces, and expected performance. Please address any modifications to existing designs necessary to meet the GPM requirements, and describe the qualification approach to ensure success.

Component specification: Provide the component specification and the requested performance data. These topics should either be addressed in a white paper or submitted as a separate document. Information for each sensor should include:

(1) Estimates of sensor accuracy, noise levels, biases, susceptibility to Earth Albedo, and all other error sources affecting the output signal quality. (2) Capabilities for aligning the MSS given the above information. Include discussion of including the alignment cube as part of the design. (3) Descriptions of the algorithms used to determine sun angle from the sensor output. This should include whether or not a “sun presence” status can be provided. In other words, can it be determined if the light seen by the sensors is from the Sun or another source. If this status can be provided, the upper limit on FOV may be changed since stray light would be less of an issue. (4) Materials list. The list will be used to determine if the hardware contains significant amounts of materials which do not demise easily, such as stainless steel and titanium. (5) Mass (kg) and dimensions (cm) for the MSS. Drawings requested. (6) Minimum natural frequency (Hz). (7) Steady-state power consumption (W). (8) Description of all electrical interfaces. Please describe if/how the component interfaces with redundant vehicle electronics. Provide component interface control document, if available. (9) Static load, random vibration and shock qualification levels. (10) Thermal qualification levels (degrees C) for operating, cold start, and survival limits requested. (11) Estimate of electromagnetic interference and electromagnetic compatibility. (EMI/EMC) per MIL-STD-461C (12) Tolerance to total ionizing dose (TID) at the part level (krad). (13) Immunity, at the parts level, to single event effects (SEE) and single event latch-up (SEL). (14) State of component development. A list of heritage missions using that component is requested. If the currently available components differ from these heritage units, please briefly describe the design changes. (15) Component design lifetime (years), both in storage and on orbit. (16) Number of hours of failure free operations on orbit. Please note any operational difficulties and mention subsequent design corrections.

Provide an estimate of the cost and schedule to deliver two flight MSS. Note any cost associated with non-recurring engineering efforts or required improvements, such custom-made baffles.

If more convenient, respondents are welcome to provide information by submitting separate attachments, such as interface control documents or electronic data files. NASA will not publicly disclose vendor proprietary information obtained in response to this RFI. To the full extent that it is protected pursuant to the Freedom of Information Act and other laws and regulations, information identified by a respondent as “Proprietary or Confidential” will be kept confidential.

GSFC is seeking capabilities from all potential sources for the purposes of determining the appropriate level of competition. This is not a solicitation announcement. If a solicitation is released, it will be synopsized in FedBizOpps and on the NASA Acquisition Internet Service. It is the potential offeror’s responsibility to monitor these sites for the release of any solicitation or synopsis. This RFI is for planning and information purposes only and it is not to be construed as a commitment by the Government to enter into a contractual agreement, nor is the Government obligated to pay for the solicited information. Respondents will not be notified of the results of the evaluation. Respondents deemed fully qualified will be considered in any resultant solicitation for the requirement.

Technical questions should be directed to: Russell Roder; Code 596; Tel. (301) 286-3436; Fax (301) 286-3823; E-mail:

Procurement related questions should be directed to: Ms. Ann Kearney, Code 210.Y, E-mail:

Comments and questions regarding this RFI are encouraged and solicited. Responses are due by July 24, 2008, and may be sent via electronic mail (in either Microsoft Word or ADOBE PDF format), regular mail, or fax to:

Ms. Ann Kearney, Mail Stop 210.5, Goddard Space Flight Center, Greenbelt, MD 20771; Telephone 301-614-5604; Fax 301-614-5619; email If you respond via regular mail or fax, please provide an electronic copy in the above formats in addition to the printed version of your submission.

When responding please reference RFI-GPM-Medium Sun Sensors

An ombudsman has been appointed — See NASA Specific Note “B”.

The solicitation and any documents related to this procurement will be available over the Internet. These documents will reside on a World Wide Web (WWW) server, which may be accessed using a WWW browser application. The Internet site, or URL, for the NASA/GSFC Business Opportunities home page is It is the offeror’s responsibility to monitor the Internet cite for the release of the solicitation and amendments (if any). Potential offerors will be responsible for downloading their own copy of the solicitation and amendments, if any.

Any referenced notes may be viewed at the following URLs linked below.

Point of Contact

Name: Ann L. Kearney
Title: Contracting Officer
Phone: 301-614-5604
Fax: 301-614-5619

SpaceRef staff editor.