Carbon-Carbon for NASA Re-Entry Heatshields
AMENDMENT ONE:
The requested due date for submittal of capabilities for this RFI is extended to the date and time indicated in the synopsis.
GENERAL INFORMATION:
To date, NASA has utilized carbon phenolic (CP) heatshields for its most demanding reentry missions, Pioneer Venus (PV) and Galileo (mission to Jupiter). It has been more than 30 years since NASA has flown a mission requiring CP TPS materials, and therefore industry's capability to support CP fabrication for NASA re-entry vehicles now and in the future is unclear.
In an effort to find alternatives to heritage reentry materials and/or systems, the NASA Ames Research Center (ARC) is seeking information on current industrial capabilities to provide Thermal Protection System (TPS) technologies for highly reliable robotic probe missions for solar system sample returns to Earth. Multiple TPS concepts are being investigated for approximately 1.0- to 2.0-meter diameter sphere-cone geometries. The purpose of this Request for Information (RFI) is to gather information on CARBON-CARBON (C-C) TPS material technologies, including material properties, current manufacturing base, current flight applications, spacecraft integration techniques, and efforts required to fabricate large heat shields. Because of the high reliability requirements of this mission class, information is also sought on manufacturing process control maturity and techniques, as-built heat shield inspection techniques, and historical qualification test history.
The intent of this RFI is to obtain data from industry in order for NASA to assess and prepare a manufacturing and maturation plan to mature C-C for NASA re-entry probes to a technology readiness level (TRL) 6 in time to support several proposed missions.
For high-reliability missions, NASA seeks to manufacture heat shields made of a C-C composite. This RFI describes the requirements in support of the initial planning phase of a C-C heat shield development for future NASA missions. NASA needs to understand current manufacturing capabilities including tools, machinery, processes and expertise, sustainability, and, if capabilities have atrophied, what would it take to revive the capabilities. To this end, information is requested from vendors that can help NASA understand their current capability to provide all elements of C-C composites including raw materials, manufacture of test articles, material testing capabilities, full-scale manufacturing demonstration units (MDUs), and eventually flight hardware. This exercise is critical in the development of processes and vendors qualified to provide flight hardware.
As this is an RFI, it should be understood that NASA makes no explicit or implied commitment for future procurements in this area.
This RFI describes the requirements in support of the initial planning phase of heat shield development for NASA's most challenging future reentry missions. NASA's long-term goal is to have a well-established industrial capability ready and available to manufacture heat shields for its multiple exploration missions across the next several decades.
SCOPE and OBJECTIVES:
Responses to this RFI should address the specific questions outlined below, as applicable to the concept described above.
1. What is your past experience in providing C-C heat shields, aeroshells, and hot structures?
A. Describe your experience making flight hardware. If you have only provided elements of flight components, please specify.
B. Personnel experienced in making C-C (number of personnel and number of years of experience)?
C. Associated product assurance certifications and processing equipment necessary to do so?
2. Do you have thermal / structural / physical material property test data (or a database including coefficients of variance) available that NASA could review? Properties of interest include:
A. Physical
i. Carbon fiber source (ENKA, NARC, etc.)
ii. Density of processed material (g/cm3)
iii. Heat of Formation (kJ/kg)
iv. Material elemental composition
B. Thermal
i. Thermal conductivity - as a function of temperature and ply- or fiber-orientation (e.g., through-thickness and in-plane, x-y-z, etc.) as appropriate (W/m*K)
ii. Specific Heat - as a function of temperature (J/g*K)
iii. Emissivity - as a function of temperature
iv. Oxidation mass-loss rates (e.g., B-prime) - as a function of temperature and pressure
C. Structural
i. Temperature-dependent shear, tensile, and compressive strength and modulus in appropriate ply- or fiber-directions
ii. High-strain rate mechanical properties if available
iii. Knock-down factors for damaged material, e.g. "open-hole" allowables
D. If you do not have the above properties, can you direct NASA to other sources where they may be available?
3. C-C material types
A. What kind of C-C materials can you manufacture? For example, 2D flat layups, 2D tape-wrapping (TW), 3D weaving, polar weaving, 2D "needling" techniques for improved through-thickness strength, etc.
B. [If applicable:] Do you see any difficulty in manufacturing a TW heat shield for a 60 deg. conical section with a 20 deg. ply angle? What experience do you have in tape wrapping? Can you make flat 20 deg. shingle angle test coupons of approximately 6-8 mm thickness?
C. [If applicable:] For 3D-type C-C materials, up to what size billets can you manufacture? What fiber/tow sizes can be used in the weaving process (x-y-z directions)?
D. Can you manufacture 3D CC parts such as curved ribs or stiffners? If so what size and shape have you made?
E. Please describe other aspects of the C-C variants you are capable of producing (e.g. different heat-treatments, tow sizes, etc.).
4. C-C manufacturing capabilities and experience
A. What thicknesses of C-C parts have you manufactured? Are there any limits to thickness or significant challenges that arise above or below certain thicknesses?
B. Given the heat shield OML geometry shown in figure 1, have similar geometries been manufactured in the past? Are there any concerns with fabricating this type of geometry utilizing your C-C capabilities?
C. Within this size range of 1.0- to 2.0-meter diameter, what capabilities do you currently have for C-C manufacturing
i. For example, do you have the mandrel, tape-wrapping machines, weaving equipment, etc., in place or do you need to design and acquire it?
ii. If the equipment is not currently running, what would be required to restore operational capability?
iii. Do you need to scale up the equipment? If so, what would certify the new scaled equipment mean in terms of cost and schedule?
iv. If you do not have operators currently trained, what would it take to get them trained?
v. How long and how much funding would be required to acquire equipment and train personnel to produce a full-scale Manufacturing Demonstration Unit (MDU)?
D. Up to what scale (base diameter) and cone angle (example 45 deg. versus 60 deg.) could you manufacture with existing infrastructure?
E. Can you make full scale Manufacturing Demonstration Units (MDUs) (between 1.0- and 2.0-meter diameter and 45- to 60-degree cone angle)? Describe the specific equipment that would be utilized for this task.
F. What is a "standard" material sample size of C-C that you can currently produce? What is the lead time for samples of that nature?
5. C-C manufacturing raw materials
A. What are the sources of your raw materials and how would you ensure their traceability?
B. Please describe the current industrial supply base for the raw materials for your C-C manufacturing. Are there any supply limitations or industrial base concerns?
C. What is the probability of providing sustained supplies of the raw materials for a future NASA mission, and are alternate supplies available?
6. C-C structural concepts, joints, and substructure interfaces
A. What methods have you used to attach C-C to various substructures and/or to different types of C-C (e.g., 2D TW frustum abutting a 3D nose cap)? To which substructure materials have you attached them? Are there any strength-loss considerations with different attachment techniques?
B. For hot structure concepts does it consist of a thick face sheet, some kind of rib stiffened structure, a multilayered approach (similar to face sheets over a honeycomb), etc. How are these structures fabricated? Are there limitations to size or shape of the parts?
C. For cold structure concepts, do you have experience with or recommendations on integration with specific insulator materials? Please provide details and examples as relevant.
D. Would the concept be manufactured as a single piece heatshield with a continuous Outer Mold Line (OML) with no seams? If the concept consists of multiple pieces with a seam at the OML describe the seam design (or design options) for that seam. (Example: Are the parts co-processed together?). Describe what kind of thermal (arcjet) and structural testing has been performed on any of the seam designs. Describe the manufacturing and integration processes for a multi-component heat shield.
7. C-C material reliability, robustness, and characterization
A. Do you have data describing the performance of your C-C material to high-velocity particle impacts (e.g., similar to orbital debris impacts)? What level of damage is observered? How would this damage affect the ability of the C-C material to undergo a re-entry heat pulse?
B. What types of Non-Destructive Evaluation (NDE) techniques are available to assess manufactured C-C parts? What types of defects can be identified using these NDE methods?
C. Are repair techniques possible for any C-C defects identified? Or do new parts need to be manufactured?
D. To what levels (e.g., heat flux and pressure in arcjet tests, laser heating, etc.) have your C-C materials been tested to? Are there any environment limitations that should be considered in use of your C-C for re-entry systems?
8. If awarded a contract, how long would it roughly take to build a 1-2m Manufacturing Demonstration Unit (MDU) from raw material procurement to final OML machining and integration?
A. Are there any specific cost/schedule drivers between 1-m and 2-m i.e. perhaps you can currently fabricate parts 1-m in diameter but would require an infrastructure upgrade if parts were bigger than 1.5-m, etc.
9. If different materials are uses for different parts of the heat shield (say the spherical nose cap versus the flank) be sure to address the questions above for all materials as appropriate.
A drawing which shows a notional 60-degree blunt-cone heat shields required by NASA with a base diameter between 1 and 2 meters is available via email from the Contracting Officer noted below, upon email request.
Interested firms are requested to submit their capability statements and responses to the questions above, as well as any comments on the acquisition approach via email to the Contracting Officer, Marianne.Shelley@nasa.gov no later than the date and time indicated in the synopsis at the Federal Business Opportunities (www.fbo.gov) procurement website. Please submit your information via email in Microsoft® Word or Adobe PDF formats.
All notices pertaining to this RFI will be posted at this Federal Business Opportunities website.
This preliminary information is being made available for planning purposes only, subject to FAR Clause 52.215-3, entitled "Request for Information or Solicitation for Planning Purposes." This is a request for information only and does not constitute a commitment, implied or otherwise, that NASA Ames Research Center (ARC) will take procurement action in this matter. Further, neither NASA ARC nor the Government will be responsible for any cost incurred in furnishing this information. NASA ARC is issuing this RFI to gain a better understanding of industry capabilities and to assess the current state of the technology.
Detailed requirements for a future acquisition have not been finalized, nor have the specifics for the acquisition strategy been determined. NASA intends to use the results of this market research to aid in the making of these final decisions. Any future procurement resulting from this RFI is contingent upon the availability of appropriated funds.
Although all comments received will be carefully reviewed and considered for inclusion in a later action, the initiators of this request make no commitment to include any particular recommendations.
Following this initial feedback, NASA may conduct one-on-one meetings with potential contractors. These meetings will allow for exchange of information and will provide an opportunity for potential offerors to provide feedback on the Government's requirements and its acquisition approach.
All information received in response to this RFI that is marked "Proprietary" will be handled and protected accordingly. As applicable, NASA may provide Proprietary information to its support service contractors who are under an obligation to keep third-party Proprietary information in confidence. By submitting a response to this RFI, the responder is deemed to have consented to release of Proprietary information to such NASA support service contractors.
Marianne Shelley, Contracting Officer, Phone 6506044179, Email marianne.shelley@nasa.gov
