DARPA STTR DPA26TZ06-DV006: Localization, Characterization, and Modeling of Freestream Disturbances in Hypersonic Wind Tunnels
Quick Answer
DPA26TZ06-DV006 is a DARPA STTR Direct to Phase II topic under the DoW 2026 STTR Broad Agency Announcement, Release 6. DARPA wants diagnostics that can measure flow and acoustic disturbances in the parts of a hypersonic wind tunnel where you cannot put a window: the driver, the reservoir, and the nozzle throat. Then it wants those measurements tied, through multi-fidelity simulation, to the freestream noise that contaminates the test section downstream. The award is $750,000 over 12 months with a $1,250,000 option over 12 months. The topic opens September 23, 2026 and closes October 21, 2026 through the Defense SBIR/STTR Innovation Portal.
The scientific problem is old and specific. Laufer established in 1964 that nozzle-wall turbulent boundary layers radiate downstream-directed Mach waves, making them a principal source of freestream noise. But in high-enthalpy and hypervelocity impulse facilities the noise field may be further enhanced by complex upstream dynamics that are not optically accessible. Standard optical techniques such as FLEET, focused laser differential interferometry, and Rayleigh scattering all require optical-grade line-of-sight window access, which may not withstand the extreme pressures, temperatures, or geometric constraints of the driver, reservoir, or nozzle throat.
Why it matters operationally: hypersonic ground test data is only as good as the tunnel's noise floor, and boundary-layer transition on a test article is exquisitely sensitive to freestream disturbance. If you cannot say where the noise comes from, you cannot correct for it, and every transition measurement carries an unquantified facility signature.
This topic is unusual in the release for two reasons. It is the only one with an OUSW Research and Engineering Critical Technology Area designation, Scaled Hypersonics. And its option period is larger than its base, $1,250,000 against $750,000, which means the majority of the money is behind a facility integration campaign that DARPA can decline to fund.
Topic At a Glance
Topic number: DPA26TZ06-DV006
Title: Localization, Characterization, and Modeling of Freestream Disturbances in Hypersonic Wind Tunnels
Agency: Defense Advanced Research Projects Agency (DARPA)
Solicitation: DoW 2026 Small Business Technology Transfer Broad Agency Announcement, Release 6, DARPA Proposal Submission Instructions
Program type: Direct to Phase II (DP2). This topic is soliciting Direct to Phase II proposals only
Technical volume format: Standard, 35 pages. Feasibility documentation is a 10-page volume, the technical proposal shall not exceed 20 pages, and the Phase II commercialization strategy shall not exceed 5 pages
Base award: $750,000
Base period of performance: 12 months
Option: $1,250,000 over 12 months
OUSW (R&E) Critical Technology Area: Scaled Hypersonics
Component Technology Priority Area: Hypersonics
Projected CMMC level requirement: Level 1
Export control status: ITAR restricted. The technology within this topic is restricted under the International Traffic in Arms Regulation, 22 CFR Parts 120-130, or the Export Administration Regulation, 15 CFR Parts 730-774
Feasibility gate: a 10-page volume providing written evidence of upstream flow and acoustic modeling, plus a proof-of-concept or benchtop demonstration of a confined-space diagnostic
Target regions: driver, reservoir, nozzle throat and walls, meaning the locations where optical access is restricted or unavailable
Base end state: Critical Design Review, with a benchtop diagnostic demonstrated at 100 kHz frequency response and structural and thermal certification by the target facility operators
Option end state: diagnostic suite integrated in a live facility at minimum Mach 5, with upstream fluctuations correlated to downstream freestream noise and a notional mitigation plan
Technical and Business Assistance: DARPA will provide up to $25,000 for the Direct to Phase II
Topic Q&A: DSIP Topic Q&A is not available for DARPA topics. Technical questions go to SBIR_BAA@darpa.mil by October 14, 2026
Topic open date: September 23, 2026
Proposal deadline: October 21, 2026. DARPA will not accept late proposals
Submission portal: DSIP at dodsbirsttr.mil
Keywords: hypersonics, wind tunnel noise, upstream disturbances, nozzle throat, driver-gas acoustics, non-optical diagnostics, high-frequency sensors, acoustic mitigation, fiber-optic probes, reflected-shock tunnels, expansion tubes
The Feasibility Bar, Which Is the First Thing to Check
This topic is soliciting Direct to Phase II proposals only. Proposers must submit a 10-page feasibility volume providing written evidence of two things.
Upstream flow and acoustic modeling
Successful modeling of upstream disturbance generation and propagation, for example driver-gas acoustic focusing, shock-tube boundary layer interactions, or nozzle throat shear layer acoustics.
Three example phenomena are named, and they correspond to three different facility classes. Driver-gas acoustic focusing is an expansion tube and tunnel problem. Shock-tube boundary layer interaction is a reflected-shock tunnel problem. Nozzle throat shear layer acoustics applies to all tunnels. Pick the phenomenon you have actually modeled, and be clear which facility class your model addresses, because that choice constrains the facility you will target in Phase II.
Confined-space diagnostic feasibility
Proof-of-concept or benchtop demonstration of a diagnostic method, for example fiber-optic-coupled probes, ultra-high-frequency flush-mounted sensors, acoustic emissions arrays, or shear sensors, demonstrating a frequency response and the physical ruggedness required to operate in high-pressure and high-temperature or non-optically accessible environments.
Note the two attributes: frequency response and physical ruggedness. Both must be demonstrated, not asserted. The Month 8 base milestone sets the specific bar at 100 kHz, which is a reasonable indication of what "high-frequency" means here, so a diagnostic with a few tens of kilohertz response has a gap to close.
What the gate screens for, and what makes this topic different
Notice what the gate does not require. There is no facility integration, no Mach number, no tunnel data. It asks for a model and a benchtop diagnostic. Compared to the other two topics in this STTR release, this is the most accessible feasibility bar, and it is well matched to a small diagnostics company partnered with a university hypersonics group.
The document also says the modeling and diagnostics work should come from "Collaborative proposals from Small Business Concerns," which is consistent with the STTR structure: the disturbance physics and simulation naturally sit with the research institution, and the sensor hardware with the small business.
Two Appendix A rules apply. Work submitted within the feasibility documentation must have been substantially performed by the proposer or the Principal Investigator, which on a university-partnered proposal means being careful about whose modeling results you are submitting and confirming that the arrangement satisfies the rule. And if the technology is subject to intellectual property, you must own the IP or have obtained license rights prior to proposal submission, with documentation in the Technical Volume.
What DARPA Is Actually Looking For
The objective
Develop and demonstrate a robust methodology to localize, characterize, and model upstream noise and flow disturbances in hypersonic wind tunnels, specifically targeting high-risk, hard-to-access regions upstream of the test section, for example the driver, reservoir, nozzle throat and walls, where traditional optical access is restricted or unavailable.
Performers must implement novel non-intrusive or minimally intrusive diagnostics coupled with multi-fidelity simulation strategies to accurately trace the evolution of unwanted thermo-fluid-dynamic disturbances from their point of origin to the test section.
The phrase "from their point of origin to the test section" is the whole topic in six words. This is a source localization and propagation tracing problem, not a noise measurement problem. Measuring test section noise is already routine. Saying which upstream feature produced it is not.
The problem
Hypersonic ground-test facilities are critical for evaluating aerodynamic forces, aerothermodynamic heating, and boundary-layer transition behavior on high-speed flight vehicles. However, conventional hypersonic wind tunnels are plagued by high-intensity freestream noise present in the test section.
Because these disturbances build, focus, and propagate downstream, the fundamental understanding of their evolution may require a potentially deep analysis within the upstream components of the facility.
Historically, Laufer established that nozzle-wall turbulent boundary layers radiate downstream-directed Mach waves, making them a principal source of freestream noise. However, especially in high-enthalpy and hypervelocity impulse facilities, the noise field may be further enhanced by complex upstream dynamics that are not optically accessible.
The three named focus areas
DARPA lists examples of focus areas, explicitly not limited to these, organized by facility type.
Nozzle throats and walls, in all tunnels. The extreme thermal and velocity gradients in the nozzle throat pose an opportunity for disturbance generation and initiation of turbulence over the nozzle walls. However, severely restricted throat geometry and high heat flux make optical diagnostic access virtually impossible. Diagnostics on tunnel walls are also very challenging, although there are examples of previous successful attempts.
Reflected-shock tunnels. Reservoir entropy, pressure fluctuations, and driver-gas contamination originate from the complex interaction between the reflected shock wave and the shock tube wall boundary layer. Furthermore, upstream diaphragm particulate-laden flow acts as a continuous source of premature model transition downstream.
Expansion tubes and tunnels. These are subject to driver-gas acoustic focusing, where upstream driver unsteadiness is focused directly into the test gas when sound speed ratios fall into unfavorable ranges. This is exacerbated by secondary diaphragm rupture wave systems propagating from upstream.
Read this list as a menu with consequences. Each focus area implies a different target facility, a different sensor environment, and a different partner. The nozzle throat is the universal option and the most brutal environment. The reflected-shock reservoir problem is the most well-characterized in the literature and the one with the most existing collaborators. The expansion tube acoustic focusing problem is the most specialized and has the fewest candidate facilities in the country.
Note also the particulate point in the reflected-shock bullet. Diaphragm particulate-laden flow causing premature model transition is a contamination problem rather than an acoustic one, and it is cited to a specific paper on shock-tube cleanliness. If your diagnostic can detect or characterize particulate, that is a differentiated capability worth calling out, since the topic frames it as a continuous source of downstream transition.
Why optical diagnostics do not solve this
Characterizing these regions is exceptionally difficult because standard optical diagnostic techniques such as Femtosecond Laser Electronic Excitation Tagging, Focused Laser Differential Interferometry, and Rayleigh scattering require optical-grade line-of-sight window access, which may not withstand the extreme pressures, temperatures, or geometric constraints of regions such as the driver, reservoir, or nozzle throat.
This is the market gap and you should state it in these terms. The hypersonics diagnostics community has excellent optical tools and no way to use them where the noise is born.
The two technical pillars
To bridge this gap, this STTR topic focuses on the development of specialized diagnostics, informed by multi-fidelity computational flow models ranging in scope from system-scale to component-specific. Collaborative proposals from Small Business Concerns must address the following technical pillars.
Upstream noise characterization and modeling. Modeling facility-specific noise generation phenomena such as transient or statistically steady boundary-layer effects, driver-gas acoustic focusing, and diaphragm bursting, starting from the most upstream location ultimately responsible for noise contamination of the test section.
Diagnostics for non-optical zones. Developing and demonstrating novel non-intrusive or minimally intrusive diagnostic systems for flow and acoustic characterization, capable of operating without traditional optical windows. Promising approaches include but are not limited to flush-mounted high-frequency pressure and thermal sensor arrays, micro-bore fiber-optic probes, laser-based acoustic sensing, and hybrid data-assimilation techniques that computationally reconstruct upstream flow states from sparse wall measurements.
The last item on that list is worth attention. Hybrid data-assimilation techniques that reconstruct upstream flow states from sparse wall measurements is a fundamentally different approach from putting a better sensor in a harder place: it accepts that you can only measure at the wall and uses the model to infer the interior. Both routes are invited. A proposal that combines them, using sparse rugged wall sensors plus assimilation into a component-scale model, sits exactly where the two pillars meet, and the topic's framing of diagnostics "informed by multi-fidelity computational flow models" suggests that is the intended shape.
Phase II Requirements
The Phase II effort will be divided into three key tasks.
Task 1: Upstream Noise Modeling and Source Characterization. Refine computational models of the targeted wind tunnel's upstream environment, focusing on detailing how disturbances generate in the driver and reservoir and focus and propagate through the throat.
Task 2: Upstream Diagnostic Suite Development. Build and calibrate a rugged, high-frequency flow and acoustic diagnostic system tailored for non-optical or highly confined spaces, for example micro-fiberoptic probes or flush-mounted acoustic arrays. Compare the novel diagnostic system developed for this task against low-order system-scale or component-specific high-fidelity predictive models.
Task 3: Facility Integration and Baseline Upstream Characterization. Deploy the diagnostic suite developed in Task 2 on the targeted wind tunnel to map baseline fluctuations directly within the upstream driver, reservoir, or throat. The measurements will correlate and support the refinement of Task 1 efforts.
Note that "the targeted wind tunnel" appears in Tasks 1 and 3, definite article. This is a facility-specific program. You are not building a general-purpose product in Phase II, you are instrumenting one tunnel, and the selection of that tunnel is a Month 4 milestone criterion. Which facility you name, and whether its operators have agreed, is likely the single most consequential decision in your proposal.
The Milestone Schedule
Phase II Base Period, 12 months
The Phase II base effort will focus on designing and validating the laboratory-scale prototype of the upstream diagnostic system and completing the engineering and integration plans for the upstream noise-mitigation hardware.
Month 4: Diagnostic System Architecture and Preliminary Design. Deliverable: Preliminary Design Review document and Upstream Diagnostic Specification Report. Criteria: selection of target wind tunnel facility completed; integration layout for upstream diagnostics, for example sensor ports and fiber-optic bypasses, finalized; preliminary numerical models of upstream mitigation hardware and observed environment completed. Associated tasks: 1 and 2.
Month 8: Diagnostic Calibration and Component Assembly. Deliverable: Confined-Space Diagnostic Calibration and Benchtop Testing Report. Criteria: successful benchtop demonstration of the diagnostic tool under simulated high-pressure and high-temperature conditions, showing a frequency response of at least 100 kHz and the ability to capture fluctuations through restricted-access ports. Associated task: 2.
Month 12: Baseline Diagnostic System Critical Design Review. Deliverable: CDR document, Upstream Structural and Thermal Safety Analysis, and Final Base Report. Criteria: final engineering drawings for upstream noise-mitigation hardware approved; structural and thermal safety and tunnel compatibility certified by target facility operators for high-pressure zones; integration interface finalized. Associated tasks: 1 and 2.
Phase II Option Period, 12 months
The Phase II option will focus on facility integration, mapping the baseline noise directly from the upstream components, and demonstrating a quantifiable reduction in freestream noise downstream.
Month 18: Facility Installation and Baseline Mapping. Deliverable: Baseline Upstream Characterization and Integration Report. Criteria: successful integration of the diagnostic suite into the target facility's upstream components, meaning reservoir, throat, or driver; baseline fluctuation measurements completed under nominal run conditions at minimum Mach 5, with and without existing noise mitigation strategies if present in the selected tunnel. Associated task: 3.
Month 24: Upstream-to-Downstream Noise Source Correlation. Deliverable: Upstream Source Localization and Propagation Analysis Report. Criteria: detailed spatial and temporal mapping of the flow path completed, successfully correlating fluctuations measured upstream, for example driver-gas acoustic focusing or throat shear-layer noise, with the resulting freestream acoustic noise in the downstream test section. Notional mitigation plan developed for observed flow characteristics.
Reading the schedule, including the thing that will decide your fate
The Month 12 criterion is the one to organize your entire base year around: structural and thermal safety and tunnel compatibility certified by target facility operators for high-pressure zones.
That is a third-party approval you do not control, for hardware you propose to install in a high-pressure section of someone else's national test asset. Facility operators at a major range or a university hypersonics laboratory are appropriately conservative about penetrations and instrumentation in the driver or reservoir, and the certification depends on their structural analysis review cycle, their safety board, and their run schedule.
The practical implication is that your target facility relationship must exist before you submit, not be developed during the base year. An existing collaboration agreement, a letter of intent from the facility, or a research institution partner who operates the tunnel is worth more than any technical claim in your proposal. If your research institution partner owns and operates the target facility, you have solved the hardest problem in the program on day one, and you should say so in the first page of your technical volume.
Note also a scope item that appears in the milestones but not in the three tasks: "upstream noise-mitigation hardware." Month 4 requires preliminary numerical models of it, and Month 12 requires final engineering drawings for it approved. The three Phase II tasks describe modeling, diagnostics, and facility integration, with no mitigation hardware task, and the option period objective mentions "demonstrating a quantifiable reduction in freestream noise downstream" while the Month 18 and Month 24 criteria ask only for measurement, correlation, and a notional mitigation plan.
So the document points in two directions on mitigation: engineering drawings for mitigation hardware are a base deliverable, but no task funds its design and no milestone requires demonstrating that it reduces noise. This is worth a question to SBIR_BAA@darpa.mil before October 14. In the meantime, the defensible approach is to scope mitigation as design and analysis only, consistent with the Month 12 drawings deliverable and the Month 24 notional plan, and to state that reading explicitly so a reviewer knows you saw the tension rather than missed it.
One more detail: the base period milestones fall at Months 4, 8, and 12, and the option milestones at Months 18 and 24. There is no Month 15 milestone, so the option period effectively runs Months 13 through 24 with reporting at its midpoint and end.
Phase III Dual Use
Military applications
High-fidelity aerodynamic and aerothermodynamic characterization of hypersonic weapons systems, glide vehicles, and interceptors across Major Range and Test Facility Bases, such as the Arnold Engineering Development Complex.
Understanding the mechanisms for tunnel noise generation directly translates to higher-fidelity ground-test data, more accurate boundary-layer transition prediction, and accelerated flight-test qualification.
The named customer is useful. AEDC and the broader MRTFB enterprise are identifiable organizations with test and evaluation budgets, and "accelerated flight-test qualification" is the benefit statement a program office responds to, because flight test is the expensive alternative to trustworthy ground test.
Commercial applications
Commercial space launch vehicle design, thermal protection system testing, and academic and commercial aerospace wind tunnel facility diagnostic upgrades.
The rugged, non-optical high-frequency diagnostic systems developed under this topic have immediate commercial application in monitoring turbulent combustion chambers, gas turbine engines, and high-pressure chemical reactors where optical access is similarly restricted.
That second paragraph is the more valuable commercial story and it is easy to skim past. The transferable product is not the hypersonics methodology, it is the sensor: a rugged, high-frequency, non-optical diagnostic that works in hot, high-pressure, optically inaccessible volumes. Combustion chambers, gas turbines, and chemical reactors are large, non-defense, recurring-revenue markets with the same physical constraint. If your commercialization strategy leads with tunnel diagnostic upgrades alone, you are describing a market of a few dozen facilities worldwide. Leading with industrial high-temperature sensing is a materially bigger case.
Export Control and the University Partnership
The technology within this topic is restricted under the International Traffic in Arms Regulation, 22 CFR Parts 120-130, which controls the export and import of defense-related material and services including export of sensitive technical data, or the Export Administration Regulation, 15 CFR Parts 730-774, which controls dual use items.
Offerors must disclose any proposed use of foreign nationals, their countries of origin, the type of visa or work permit possessed, and the statement of work tasks intended for accomplishment by the foreign nationals, in accordance with the Announcement.
Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US export control laws.
Why this needs early attention
Hypersonics is among the most export-controlled technical areas in aerospace, and university hypersonics laboratories are staffed substantially by international graduate students and postdoctoral researchers. This is an STTR, so a single partnering research institution must perform at least 30 percent of the work.
Resolve this before you submit. Identify which institution personnel will perform which tasks and their citizenship or visa status, since Appendix A requires that disclosure in the technical volume. Engage the institution's export control and research compliance office in the first week. Settle the Fundamental Research determination, since DARPA requires you to either separate Fundamental Research tasks into their own statement of work or identify them within the prime statement of work, and that determination interacts directly with the ITAR restriction and with DARPA's stated right to impose publication restrictions.
A note on the CMMC designation
The projected CMMC requirement for this topic is Level 1, which sits oddly beside the ITAR restriction. The DARPA STTR front matter states that firms engaging in Controlled Unclassified Information, Export Controlled, or ITAR work for DARPA must have CMMC Level 2 self-assessment certification, and Appendix A states that those engaging in ITAR or CUI work must have Level 2 CMMC certification.
Compare topic DV005 in this same release, which is also ITAR restricted and carries a projected CMMC Level 2 (Self) requirement. The Level 1 projection on an ITAR-restricted topic is worth clarifying with DARPA. The prudent planning assumption is Level 2 self-assessment, since that is what the general CMMC language requires for ITAR work regardless of the topic-level projection, and a Level 2 posture satisfies both readings.
Funding, Cost Structure, and DARPA Mechanics
The award
$750,000 over a 12 month base, plus a $1,250,000 option over 12 months, for $2,000,000 across 24 months if the option is exercised.
This is the only topic in either DARPA Release 6 document where the option is larger than the base, and it is a 62 percent share. The structure follows the technical logic: the base is design and benchtop work, the option is a live facility campaign that costs real tunnel run time. But it also means the Government reserves the right to award all, some, one, or none of the options based on available funding and the performer's technical performance, and in this case that decision governs most of the program value and all of the interesting data.
Two implications. Design the base year so the option decision is easy, which here means hitting the 100 kHz benchtop demonstration cleanly and, above all, delivering the facility operators' structural and thermal certification on time. And be realistic that $750,000 over 12 months for two tasks plus a facility relationship is a modest budget, so the base year plan should be lean and focused rather than exploratory.
The resources made available under each topic will depend on the quality of the proposals received and the availability of funds.
Contract type
Multiple awards are anticipated. DARPA may award FAR-based Government contracts, firm-fixed-price or cost-plus reimbursement, or Other Transactions for Prototypes agreements under the authority of 10 U.S.C. 4022, subject to approval of the Contracting Officer or Agreements Officer respectively. Note that the companion DARPA SBIR Release 6 instructions cite 10 U.S.C. 4021 for the same instrument type.
The Government Contracting Officer reserves the right to select award instrument type regardless of what was proposed and to negotiate all terms. DARPA reserves the right to remove a proposal from award consideration if the parties fail to reach agreement within a reasonable time or if the proposer fails to provide requested additional information within three business days. Complete the DARPA SBIR/STTR Pre-Award Checklist before selection.
DARPA will apply publication or other restrictions if it determines the research presents a high likelihood of disclosing performance characteristics of military systems or manufacturing technologies unique and critical to defense, and any such award will require DARPA permission before publishing. On a hypersonics topic with a university partner, treat this as likely rather than hypothetical and raise it with your institution early.
Templates are mandatory
Templates for Volume 2 Technical Volume and Volume 3 Cost Volume are provided as attachments to the announcement at dodsbirsttr.mil, and use of these templates is mandatory. The Volume 3 Direct to Phase II Cost Proposal Template is an Excel spreadsheet on the DARPA Small Business site.
Cost substantiation
All proposed costs should be accompanied by documentation substantiating how the cost was derived: paystubs or a DCMA rate agreement for direct labor, historical invoices or a current contract for consultants, and historical invoices, current quotes, or market research for materials and equipment. You need not propose the cheapest supplier but should explain the choice.
All subcontractor and consultant costs must be detailed at the same level as prime contractor costs and substantiated with Subcontractor Pricing Considerations under FAR 15.404-3(b), entered in the Explanatory Material section of the cost proposal form. Subcontractors should send unsanitized cost proposals directly to SBIR_BAA@darpa.mil.
Three cost centers on this topic deserve documented rates. The research institution subaward, since it performs at least 30 percent of the work. Tunnel run time in the option period, which is billed by the shot or by the day depending on the facility and needs a rate basis from the operator. And high-bandwidth data acquisition, since 100 kHz-class measurements across a sensor array generate a real instrumentation and storage requirement.
If subcontractors will be performing Fundamental Research, you must either provide a separate statement of work for that work or identify those tasks within the prime statement of work. Cost sharing is permitted but not required and is not an evaluation factor. Title to property acquired with Government funds vests with DARPA unless transfer is determined more cost effective, which matters if your plan includes purchasing significant sensor or acquisition hardware.
Technical and Business Assistance
The Small Business Innovation and Economic Security Act Section 7 mandates agencies to offer TABA. DARPA will provide up to $25,000 for the Direct to Phase II.
Note what this document does not say. Unlike the companion DARPA SBIR Release 6 instructions, it does not state that TABA is in addition to the cost ceiling and not subject to profit or fee. Do not assume the SBIR language transfers. TABA requests will be reviewed by the respective contracting office or specialist at time of award.
For this topic, export control counsel and industrial market development are the two highest-value uses, the latter because the commercial case runs through combustion, turbine, and reactor sensing rather than through wind tunnels.
Questions and the FAQ
DSIP Topic Q&A will not be available for these DARPA topics. Technical questions must be submitted by October 14, 2026, by email to SBIR_BAA@darpa.mil with the topic number in the subject line, including the name, email address, and telephone number of a point of contact. All questions must be in English.
Questions submitted within seven calendar days of the proposal due date may not be answered. DARPA posts a consolidated Frequently Asked Questions document under the topic number summary on its Small Business site, updated on an ongoing basis until one week prior to the proposal due date.
DSIP technical support is available Monday through Friday, 9:00 a.m. to 5:00 p.m. Eastern, at DoDSBIRSupport@reisystems.com with a copy to SBIR_BAA@darpa.mil.
DARPA will not accept any late proposals.
Proposal format details
The Technical Volume must be a single PDF including graphics. Virus check before uploading. Do not lock or encrypt. Do not embed active graphics such as videos or moving pictures. Number all pages consecutively. Font no smaller than 10-point on 8.5 by 11 inch paper with one-inch margins. The header on each page should contain your company name, the topic number, and the DSIP-assigned proposal number, and may sit in the one-inch margin.
The Proposal Cover Sheet must include a technical abstract of no more than 3000 characters. Do not include marketing material, which will not be evaluated.
Classification, marking, and registrations
All proposals must be UNCLASSIFIED or CUI. No classified information. No proprietary information on the Proposal Coversheet in Volume 1, which may be released publicly if selected for award. Proprietary or CUI content may go in the Technical Volume, marked with the appropriate CUI Control Block on the first page. The Cost Volume should be marked CUI for PROPIN. Volumes 4 through 7 marked as appropriate based on content.
Titles, abstracts, anticipated benefits, and keywords of selected proposals undergo DARPA Policy and Security Review and may be revised or redacted, with final versions potentially appearing on the DoW SBIR/STTR awards website and sbir.gov/awards.
Maintain an accurate and active SAM.gov entity registration. Given the ITAR restriction, confirm your CMMC posture in SPRS as discussed above. DARPA points to sprs.csd.disa.mil/nistsp.htm and Project Spectrum at projectspectrum.io.
On venture capital ownership
The DARPA STTR Release 6 instructions contain no provision addressing majority ownership by venture capital operating companies, hedge funds, or private equity firms. The companion DARPA SBIR Release 6 instructions do include such a provision, explicitly permitting it under three conditions.
Do not read the SBIR provision across to this document. Eligibility for STTR awards is governed by the DoW STTR Program BAA and the SBA SBIR/STTR Policy Directive. If your ownership structure raises the question, resolve it before investing in a proposal.
Evaluation and selection
All proposals will be evaluated in accordance with the evaluation criteria listed in the DoW STTR Program BAA. Proposals that do not comply with the requirements detailed in this BAA and the research objectives of the corresponding topic are considered non-conforming and will not be evaluated nor considered for award.
Appendix A adds a second trap: proposals that do not adequately substantiate prior Phase I-equivalent feasibility for the components addressed will be deemed non-responsive and will not be evaluated for award.
The Government will evaluate each proposal in its entirety, documenting strengths and weaknesses against each criterion, and determine overall selectability. Proposals are not evaluated against each other but on their own individual merit. A selectable proposal is one where strengths outweigh weaknesses with no accumulated weaknesses requiring extensive negotiations or a resubmitted proposal.
Awards will be made to proposers whose proposals are most advantageous to the Government, consistent with the DoW STTR Program BAA criteria and availability of funding.
Notification of selection or non-selection within 90 calendar days of BAA close, by email to the Corporate Official on the Proposal Cover Sheet. DARPA will provide a technical evaluation narrative for each proposal, and an informal feedback session may be requested at sbir@darpa.mil at DARPA's sole discretion.
Company Commercialization Report information will not be considered during evaluations.
Protests regarding the selection decision go, as prescribed in FAR 33.106(b) and FAR 52.233-3, to DARPA Contracts Management Office, 675 N. Randolph Street, Arlington, VA 22203, by email to CMO_SBIRProtests@darpa.mil and sbir@darpa.mil.
Post-award support
DARPA provides Transition and Commercialization Support Program services to Phase II awardees upon contract execution at no cost. Awardees may also be eligible for the Embedded Entrepreneurship Initiative, invitation-only at DARPA's sole discretion, typically no more than $310,000 per awardee over the duration of the award, supporting a Senior Commercialization Advisor relationship, investor working group connections, and hiring an embedded entrepreneur to execute a Go-to-Market strategy. Your commercialization strategy section is used to assess EEI suitability, and EEI selection happens independently after award selection.
The References
Twelve, and they are the most demanding reading list in either DARPA Release 6 document. They also sort neatly into the three focus areas, which tells you how to read them.
The foundation. Laufer, "Some Statistical Properties of the Fluctuations in the Boundary Layer of a Supersonic Nozzle," Physics of Fluids, 1964. This is the nozzle-wall Mach wave radiation result that the topic description builds on.
Quiet tunnels and the state of the art. Schneider, "The Development of Hypersonic Quiet Tunnels," Journal of Spacecraft and Rockets, 2008. Hornung, "Performance of and Noise in High-Enthalpy Wind Tunnels," AIAA Paper 93-0185, 1993.
Transition in impulse facilities. Parziale, Shepherd, and Hornung, "Observations of Hypervelocity Boundary Layer Transition on a Cone in a Shock Tunnel," Journal of Fluid Mechanics, 2014.
Reflected-shock tunnel physics. Davies, "The Interaction of the Reflected Shock with the Boundary Layer in a Shock Tube and its Influence on the Duration of Hot Flow in the Reservoir," Aeronautical Research Council CP-881, 1966. Hannemann, Schnieder, Reimann, and Martine Schramm, "The influence and the delay of driver gas contamination in HEG," AIAA 2000-2593.
Particulate contamination. Jewell, Parziale, Leyva, and Shepherd, "Effects of Shock-Tube Cleanliness on Hypersonic Boundary Layer Transition at High Enthalpy," AIAA Journal, 2017.
Expansion tube physics. Trimpi, "A Preliminary Theoretical Study of the Expansion Tube," NASA Technical Report, 1962. Paull and Stalker, "Acoustic waves in shock tunnels and expansion tubes," 18th International Symposium on Shock Waves, 1991. Dufrene, Sharma, and Austin, "Design and Characterization of a Hypervelocity Expansion Tube Facility," Journal of Propulsion and Power, 2007. Furukawa et al., "Visualizing the Secondary Diaphragm Rupture in an Expansion Tube," Shock Waves, 2007.
Wall diagnostics precedent. Kasper et al., "Pressure fluctuations beneath instability wavepackets and turbulent spots in a hypersonic boundary layer," Journal of Fluid Mechanics.
Two observations. First, the Kasper reference is the one the topic points to when it says diagnostics on tunnel walls are challenging "although there are examples of previous successful attempts." That is your precedent for flush-mounted wall sensing, and citing it while explaining what you add is a strong opening for the diagnostics pillar. Second, Paull and Stalker 1991 is the acoustic focusing mechanism, and the sound speed ratio condition it identifies is the physics behind the expansion tube focus area. If you target that focus area, that paper is load-bearing.
Timeline and What to Do When
The dates
Topic opens: September 23, 2026
Technical question deadline: October 14, 2026, to SBIR_BAA@darpa.mil with the topic number in the subject line
Proposal deadline: October 21, 2026. DARPA will not accept late proposals
Selection notification: within 90 calendar days of BAA close
Base period: 12 months from award
Option: 12 additional months if exercised
A working backward plan
Before September 23. Choose your focus area and your target facility, in that order, and secure the facility relationship in writing. This is the highest-value pre-submission action available on this topic, because the Month 12 criterion requires certification by the facility operators and the option period requires physical integration into their tunnel. Commit your research institution partner, ideally one that operates the target facility. Work the ITAR and export control question with their compliance office immediately, identifying personnel, citizenship or visa status, and assigned tasks. Settle the Fundamental Research determination and raise DARPA's publication restriction language. Verify your benchtop diagnostic's frequency response against the 100 kHz Month 8 bar and its ruggedness under simulated high-pressure and high-temperature conditions. Assemble your upstream modeling evidence for the specific phenomenon you will target. Resolve IP ownership or licensing, since documentation goes in the Technical Volume. Confirm your CMMC posture, planning to Level 2 self-assessment given the ITAR restriction. Download the mandatory Volume 2 and Volume 3 templates. Read the FAQ and keep rechecking it. Read Laufer 1964, Kasper, and the references for your chosen focus area. Decide your contract type. Confirm SAM registration.
September 23 through October 5. Draft the 10 page feasibility volume first, covering both required elements: the upstream modeling evidence and the confined-space diagnostic demonstration. Include the reference list on the last page, counting toward the limit, and the one-page commercialization potential summary. Then draft the 20 page technical proposal against Appendix A's sections, with the statement of work as a substantial portion, organized around Tasks 1 through 3 and the five milestones. Name your target facility and its operator agreement early and prominently. Address the mitigation hardware scope question explicitly. Include the foreign citizens disclosure. Send your questions to SBIR_BAA@darpa.mil, including the mitigation scope question and the CMMC level question.
October 6 through October 14. Build the cost volume in the mandatory Excel template across the 12 month base and 12 month option. Get the research institution's budget at prime-level detail with Subcontractor Pricing Considerations. Get a documented rate basis for tunnel run time in the option period from the facility operator. Price high-bandwidth data acquisition, sensor fabrication, the benchtop high-pressure and high-temperature test rig, structural and thermal analysis labor for the certification package, and computational resources for the multi-fidelity modeling. Draft the 5 page transition and commercialization strategy against Appendix A's nine elements, leading with industrial high-temperature sensing rather than tunnel upgrades alone.
October 15 through October 18. Assemble Volume 5 with data rights assertions, IP documentation, CVs, subcontractor pricing considerations, and any optional letters of intent, particularly from the target facility operator, AEDC, or an MRTFB organization, to substantiate specific transition claims. Complete Volume 6 training and the Volume 7 foreign affiliations webform, which the Corporate Official must submit before certification is possible. Run compliance: single unlocked PDF, no embedded video, 10-point minimum font, consecutive page numbers, correct header, 3000 character abstract, CUI marking, mandatory Excel cost template, no marketing material.
October 19 through October 20. Submit and certify in DSIP, and confirm the mandatory supporting documents actually uploaded, since a completed submission in DSIP does not indicate that they did.
Frequently Asked Questions
What is DARPA STTR topic DPA26TZ06-DV006?
DPA26TZ06-DV006 is a DARPA STTR Direct to Phase II topic titled "Localization, Characterization, and Modeling of Freestream Disturbances in Hypersonic Wind Tunnels," released under the DoW 2026 STTR Broad Agency Announcement, Release 6. The objective is to develop and demonstrate a robust methodology to localize, characterize, and model upstream noise and flow disturbances in hypersonic wind tunnels, targeting hard-to-access regions upstream of the test section such as the driver, reservoir, and nozzle throat and walls, where traditional optical access is restricted or unavailable.
How much funding is available?
The base award is $750,000 over 12 months, with a $1,250,000 option over 12 months, for a maximum of $2,000,000 across 24 months if the option is exercised. This is the only topic in either DARPA Release 6 document where the option is larger than the base. DARPA will also provide up to $25,000 in Technical and Business Assistance for the Direct to Phase II.
When is the proposal deadline?
The topic opens September 23, 2026 and proposals are due October 21, 2026 through the Defense SBIR/STTR Innovation Portal at dodsbirsttr.mil. DARPA will not accept late proposals.
Can I submit a Phase I proposal?
No. This topic is soliciting Direct to Phase II proposals only.
What must my feasibility volume show?
Two things, in a 10-page volume. Successful modeling of upstream disturbance generation and propagation, for example driver-gas acoustic focusing, shock-tube boundary layer interactions, or nozzle throat shear layer acoustics. And a proof-of-concept or benchtop demonstration of a diagnostic method, for example fiber-optic-coupled probes, ultra-high-frequency flush-mounted sensors, acoustic emissions arrays, or shear sensors, demonstrating the frequency response and physical ruggedness required for high-pressure, high-temperature, or non-optically accessible environments.
What frequency response do I need?
The feasibility requirement does not state a number, but the Month 8 base milestone requires a benchtop demonstration showing a frequency response of at least 100 kHz along with the ability to capture fluctuations through restricted-access ports. Plan against 100 kHz.
Why can't optical diagnostics do this already?
Standard techniques such as FLEET, focused laser differential interferometry, and Rayleigh scattering all require optical-grade line-of-sight window access, which may not withstand the extreme pressures, temperatures, or geometric constraints of the driver, reservoir, or nozzle throat. That is the gap the topic exists to fill.
Which upstream regions does DARPA care about?
Three focus areas are named as examples, not limits. Nozzle throats and walls in all tunnels, where extreme thermal and velocity gradients generate disturbance and initiate wall turbulence but restricted geometry and high heat flux make optical access virtually impossible. Reflected-shock tunnels, where reservoir entropy, pressure fluctuations, and driver-gas contamination arise from reflected shock interaction with the shock tube wall boundary layer, and where diaphragm particulate-laden flow causes premature model transition. And expansion tubes and tunnels, subject to driver-gas acoustic focusing when sound speed ratios fall into unfavorable ranges, exacerbated by secondary diaphragm rupture wave systems.
What are the three Phase II tasks?
Task 1, upstream noise modeling and source characterization, refining computational models of the targeted tunnel's upstream environment. Task 2, upstream diagnostic suite development, building and calibrating a rugged high-frequency diagnostic for non-optical confined spaces and comparing it against low-order system-scale or component-specific high-fidelity predictive models. Task 3, facility integration and baseline upstream characterization, deploying the suite on the targeted tunnel to map baseline fluctuations in the driver, reservoir, or throat.
Do I have to name a specific wind tunnel?
Effectively yes. Selection of the target wind tunnel facility is a Month 4 milestone criterion, and Tasks 1 and 3 both refer to "the targeted wind tunnel." More importantly, the Month 12 criterion requires structural and thermal safety and tunnel compatibility certified by the target facility operators for high-pressure zones, which is a third-party approval you cannot obtain without an existing relationship.
What is the hardest milestone?
Month 12, because it requires certification by facility operators of structural and thermal safety and tunnel compatibility for high-pressure zones. That approval depends on someone else's safety review process and run schedule. A proposal whose research institution partner operates the target facility has a decisive advantage here.
What does the option period require?
Integration of the diagnostic suite into the target facility's upstream components with baseline fluctuation measurements at minimum Mach 5, with and without existing noise mitigation strategies if present in the selected tunnel, by Month 18. Then by Month 24, detailed spatial and temporal mapping correlating upstream fluctuations with the resulting downstream freestream acoustic noise, plus a notional mitigation plan.
Am I expected to build noise mitigation hardware?
The document is not fully consistent on this. The Month 4 criterion requires preliminary numerical models of upstream mitigation hardware, and Month 12 requires final engineering drawings for it approved. But none of the three Phase II tasks covers mitigation hardware design, and the Month 18 and Month 24 criteria ask only for measurement, correlation, and a notional mitigation plan, even though the option period objective mentions demonstrating a quantifiable reduction in freestream noise. Ask DARPA at SBIR_BAA@darpa.mil before October 14. The defensible reading is design and analysis only, consistent with the drawings deliverable and the notional plan.
Do I need a research institution partner?
Yes. STTR awards require a formal partnership with a single partnering research institution, with the small business performing at least 40 percent of the work and the research institution at least 30 percent. The DARPA instructions direct proposers to the DoW STTR Program BAA for these general requirements. This topic does not prescribe the role split, but the natural division puts the disturbance physics and multi-fidelity modeling with the institution and the sensor hardware with the small business.
Is this topic ITAR restricted?
Yes. The topic states the technology is restricted under ITAR, 22 CFR Parts 120-130, or EAR, 15 CFR Parts 730-774. Offerors must disclose any proposed use of foreign nationals, their countries of origin, visa or work permit type, and the statement of work tasks they will perform. Foreign nationals proposed to perform on this topic may be restricted.
How does ITAR interact with a university hypersonics lab?
This is the practical problem to solve first. Hypersonics is heavily export controlled and university hypersonics groups are typically staffed substantially by international students and postdocs, while the institution must perform at least 30 percent of the work. Identify personnel and status, assign tasks accordingly, engage the institution's export control office immediately, and settle the Fundamental Research determination, which interacts with both the ITAR restriction and DARPA's stated right to impose publication restrictions.
What CMMC level applies?
The projected requirement stated for this topic is Level 1, which sits oddly beside the ITAR restriction, since both the DARPA STTR front matter and Appendix A state that firms engaging in ITAR, Export Controlled, or CUI work for DARPA must have CMMC Level 2 certification. The comparable ITAR-restricted topic in this release, DV005, carries a projected Level 2 (Self) requirement. Worth clarifying with DARPA; the prudent planning assumption is Level 2 self-assessment.
How long can my technical volume be?
The standard format is 35 pages. The feasibility volume is 10 pages, the technical proposal shall not exceed 20 pages, and the Phase II commercialization strategy shall not exceed 5 pages and should be the last section of the Technical Volume. Appendix A states the commercialization strategy will not count against the proposal page limit, so confirm with DARPA how the three numbers combine if it affects your layout. Font must be at least 10-point.
Can I ask questions through DSIP Topic Q&A?
No. DSIP Topic Q&A is not available for DARPA topics. Technical questions go by email to SBIR_BAA@darpa.mil by October 14, 2026, with the topic number in the subject line and a point of contact name, email, and phone number. DARPA maintains a consolidated FAQ on its Small Business site.
What contract types can DARPA award?
FAR-based firm-fixed-price or cost-plus reimbursement contracts, or Other Transactions for Prototypes agreements under the authority of 10 U.S.C. 4022. Note that the companion DARPA SBIR Release 6 instructions cite 10 U.S.C. 4021 for the same instrument type.
Will DARPA restrict publication?
Possibly, and on a hypersonics topic it is worth planning for. DARPA states it will apply publication or other restrictions if it determines the research presents a high likelihood of disclosing performance characteristics of military systems or manufacturing technologies unique and critical to defense, and that any such award will require DARPA permission before publishing. Raise this with your university partner early.
Are venture capital backed companies eligible?
The DARPA STTR Release 6 instructions contain no provision on majority ownership by venture capital operating companies, hedge funds, or private equity firms, unlike the companion DARPA SBIR Release 6 instructions, which explicitly permit it under three conditions. Do not assume the SBIR provision applies here. Check the DoW STTR Program BAA and the SBA SBIR/STTR Policy Directive, or ask DARPA before October 14.
How much cost documentation do I need?
All proposed costs should be accompanied by documentation substantiating how the cost was derived, such as paystubs or a DCMA rate agreement for labor, contracts or historical invoices for consultants, and quotes, invoices, or market research for materials and equipment. Subcontractor and consultant costs must be detailed at prime-level and substantiated with Subcontractor Pricing Considerations under FAR 15.404-3(b). Subcontractors send unsanitized cost proposals to SBIR_BAA@darpa.mil. For this topic, get a documented rate basis for tunnel run time from the facility operator.
How will my proposal be evaluated?
Against the evaluation criteria in the DoW STTR Program BAA. Proposals are evaluated individually on their own merit rather than against each other. A selectable proposal is one where strengths outweigh weaknesses with no accumulated weaknesses requiring extensive negotiation or resubmission. Non-conforming proposals, and proposals that do not adequately substantiate prior Phase I-equivalent feasibility, are not evaluated at all.
Will I get feedback if not selected?
Yes. DARPA will provide a technical evaluation narrative for each proposal submitted, and an informal feedback session may be requested by email at sbir@darpa.mil, granted at DARPA's sole discretion.
What is the commercial market?
Commercial space launch vehicle design, thermal protection system testing, and academic and commercial wind tunnel diagnostic upgrades. More significantly, the rugged non-optical high-frequency diagnostic systems have immediate application in monitoring turbulent combustion chambers, gas turbine engines, and high-pressure chemical reactors where optical access is similarly restricted, which is a much larger market than wind tunnels.
Who do I contact with questions?
Technical questions go to SBIR_BAA@darpa.mil with the topic number in the subject line, by October 14, 2026. Administrative questions about the DARPA program and these instructions also go to SBIR_BAA@darpa.mil. DSIP technical support is DoDSBIRSupport@reisystems.com with a copy to SBIR_BAA@darpa.mil. Feedback session requests go to sbir@darpa.mil.
Positioning Advice for Companies Considering This Topic
Secure the target facility before you write a word. The Month 12 criterion requires structural and thermal safety and tunnel compatibility certified by the facility operators for high-pressure zones, and the entire option period is a campaign inside their tunnel. This is the one thing in the program you cannot buy with technical excellence. A signed collaboration agreement, a facility letter of intent, or a research institution partner that operates the tunnel is worth more than any diagnostic claim. Name the facility on page one.
Pick one focus area and commit. Nozzle throat, reflected-shock reservoir, or expansion tube driver acoustics are three different physics problems in three different facility classes with three different sensor environments. A proposal that gestures at all three reads as unfocused and, worse, cannot name a single target facility credibly. Choose the one where you have both modeling evidence and a facility relationship.
Bring the sensor and the model together, not separately. The topic frames diagnostics as "informed by multi-fidelity computational flow models," and it explicitly invites hybrid data-assimilation techniques that reconstruct upstream flow states from sparse wall measurements. That combination, rugged sparse wall sensing plus assimilation into a component-scale model, sits exactly where the two technical pillars meet and is the most defensible answer to a problem where you fundamentally cannot instrument the interior.
Demonstrate ruggedness, not just bandwidth. Two attributes are required at the gate and at Month 8: frequency response and physical ruggedness under simulated high-pressure and high-temperature conditions. Most sensor proposals will lead with bandwidth. Showing survival data, thermal drift characterization, and a mounting concept that a facility safety board would accept is the differentiator, and it happens to be exactly what the Month 12 certification will hinge on.
Budget the certification package as real engineering. Structural and thermal safety analysis for a penetration into a high-pressure driver or reservoir is a stress and thermal analysis deliverable reviewed by a third party, not a paperwork item. Staff it, price it, and schedule it against the facility's review cycle rather than against your own calendar.
Design the base year for the option decision. Sixty-two percent of the money is in the option, and DARPA can decline it. The base year has three milestones and two of them, the 100 kHz benchtop demonstration and the operator-certified CDR, are the option decision. Keep the base plan lean and focused on those two things rather than exploring the design space.
Ask the mitigation hardware question. The milestones require preliminary models and then approved final engineering drawings for upstream noise-mitigation hardware, while no task funds its design and no milestone requires proving it reduces noise. Send the question to SBIR_BAA@darpa.mil, scope it as design and analysis in your proposal, and say plainly that this is your reading. Showing that you read the document carefully is itself a signal.
Lead your commercialization strategy with industrial sensing, not wind tunnels. There are a few dozen relevant hypersonic facilities worldwide. There are thousands of combustion chambers, gas turbines, and high-pressure reactors with the same optical access problem, and DARPA named them itself. That inversion turns a niche instrumentation product into a real market, which is what the commercialization strategy is scored on.
Solve the ITAR and university problem in week one. Hypersonics plus a foreign national disclosure requirement plus a university performing at least 30 percent of the work is the most likely reason a strong team here fails to submit. Personnel, status, task assignment, compliance office, Fundamental Research determination, publication restrictions. Do it first.
Cite Kasper and Laufer, and the references for your focus area. Laufer 1964 is the foundation the topic builds on and Kasper is the wall-diagnostics precedent the topic alludes to when it says there have been previous successful attempts. Positioning your approach against those two, then against the specific references for your chosen focus area, demonstrates the awareness of the state of the art that Appendix A explicitly requires you to persuade reviewers of.
Say what "localization" means quantitatively. The topic asks you to trace disturbances from their point of origin to the test section. A proposal that states a spatial resolution or a source discrimination capability, even approximately, is making a testable claim. One that promises to "correlate upstream and downstream measurements" is not. The Month 24 criterion asks for detailed spatial and temporal mapping, so define what detail you expect to achieve.
Do not import the SBIR document's provisions. Three concrete differences matter: the OT authority citation is 4022 here rather than 4021, there is no venture capital ownership provision, and the TABA language omits the statement that TABA sits on top of the cost ceiling. If you are bidding both programs this cycle, read both documents.
