NSF SAK Peak JA redacted Copy_signed.pdf

National Science Foundation 401 Dulaney Street • Alexandria, Virginia 22314

CUI//SP-CONTRACT

JUSTIFICATION AND APPROVAL

SUBJECT: Justification for Other Than Full and Open Competition for Structural Engineering and Liquid Mercury Removal and Remediation Services for the Dunn Solar Telescope (DST)

The purpose of this memorandum is to capture, in accordance with FAR Part 6 requirements, the circumstances and rationale supporting the use of other than full and open competition for a sole source contract award for emergency engineering and hazardous materials services.

This memorandum is a product of the known facts and circumstances during the period in which it was written.

Pursuant to the requirements of the Competition in Contracting Act (CICA) as implemented by the Federal Acquisition Regulation (FAR) Subpart 6.1 and consistent with the content requirements of FAR 6.104-1(a) the following facts and rationale justify the use of such authority.

6.104-1(a)(1): Agency and Contracting Activity.

The National Science Foundation, Office of Chief Financial Officer, proposes to issue a contract on behalf of NSF Office of Research Infrastructure (NSF ORI), on a basis of other than full and open competition, for the award of a 12-month contract for structural engineering, liquid mercury removal, and remediation for the Richard B. Dunn Solar Telescope (DST).

6.104-1(a)(2): Nature and/or description of the action being approved.

The intent of the U.S. National Science Foundation (NSF) is to do an immediate forensic engineering assessment of the structural integrity of the Dunn Solar Telescope and rapid hazardous materials remediation due to a large liquid mercury leak and the potentially imminent environmental and safety risks inside the telescope. The source of the leak is not yet addressed; therefore, time is of the essence to halt the leak, stabilize the structure, drain the remaining liquid mercury, remediate any environmental hazards, and conduct selective interior demolition of the interior elements of the tower (i.e., the mercury-containing vacuum tube and related components).

BACKGROUND

Description of the Dunn Solar Telescope

The DST, built by the US Air Force in 1969, is located at NSF’s Sacramento Peak Observatory. It took approximately 10 years to construct due to the complexity and scale of the project. The following provides a description of DST features:

DST extends to 136 feet above ground and 228 feet below ground.

Vertical vacuum tube for the telescope is enclosed within a concrete tower with 3-foot-thick walls and is supported by three oversized screws.

Interior vacuum tube weighs more than 200 tons and is suspended by a bearing that contains approximately 10 metric tons of mercury located 93 feet above ground surface.

A workstation lift is located on the interior wall. The workstation lift functions like an elevator, but it moves a workstation from the basement level to the main observation deck.

In addition to the telescope structure, the facility includes offices, data processing rooms, maintenance, and storage.

Minimal updates have occurred at the building, including in the basement where some of the fractured limestone remains in place.

The DST contains approximately 160 gallons (approximately 18,000 lbs) of liquid mercury used in the telescope’s bearings and seals. On January 5, 2026, a liquid mercury release was discovered inside the DST on the main floor worktable. Safety protocols were immediately implemented and the proper authorities notified. NSF immediately worked with the steward of the facility to engage hazardous materials remediators to clean up the mercury and identify the source of the leak.

As of January 15, 2026, hazardous materials experts had cleaned and properly disposed of approximately 186 lbs (84 kg) of the released elementary mercury from platforms located at the 30-foot and 70-foot levels. On January 16th, a crack was discovered at the weld between the existing mercury valve and the bottom of the bearing. Mercury appeared to have leaked from that area but was not actively dripping at that time. A container was placed beneath this area to catch any drips, and the facility was closed to personnel. At this time, the full cause and location(s) of the mercury release is unknown. The known crack has not been sealed, so this is an active situation. Given the age of the infrastructure, the root cause of the initial failure has not been determined. While one structural crack has been identified at the weld location, it is unknown whether additional cracks, material degradation, or structural weaknesses exist within the bearing assembly or related components.

Following identification of the structural crack, NSF engaged with the steward and operator of the DST to address the mercury clean up and identification of the leak source, which required a full structural assessment. The operator undertook efforts within its operational authority. As additional technical information became available, including initial engineering assessments, NSF, in mid-February 2026, determined that the scope, complexity, and risk profile of the required structural stabilization and full mercury removal exceeded the operator’s contractual capabilities and available resources. The required effort involves specialized forensic structural engineering expertise integrated with large-scale hazardous materials containment and environmental response services beyond routine facility operations.

Without knowing what caused the initial mercury crack beyond ailing infrastructure, the concern is that the crack may widen suddenly, or that additional undetected structural failures may occur, causing a catastrophic leak in which a portion or all the mercury in the bearing could be released in a very short time from a great height. The situation is both dangerous to personnel and a significant environmental hazard. An initial engineering assessment estimates that if the crack widens it may result in a catastrophic release of all he mercury, taking only five (5) minutes for the mercury to completely evacuate the bearings. Based on weight of the liquid mercury and gravitational force, a catastrophic release would result in approximately 18000 lbs of liquid mercury flooding the middle and lower portions of the facility.

Trying to contain such an unplanned release of mercury and protect personnel will be incredibly difficult in that mercury is approximately 13.5 times denser than water and has unique properties (e.g., it tends to move in elastic collisions, or bounces, as it falls) potentially creating much greater safety risks and costs for environmental clean-up within the telescope.

Multiple hazardous materials and safety experts and engineers are working on this issue, but the potential size of this release is unprecedented. DST facility has remained closed and sealed until further structural and safety assessments are made.

Given the anticipated costs for assessing and repairing vulnerabilities in this aging structure, and the safety and environmental risks associated with the approximately 160 gallons of liquid mercury used in the facility’s bearings and seals, NSF determined that the most prudent action is to stabilize the structure, completely drain the internal mechanisms of mercury, and remove any mercury and mercury-contaminated materials from the site as soon as possible.

This necessary action will effectively render the DST inoperable.

DST and its supporting infrastructure sit on National Forest System lands, managed by the U.S. Department of Agriculture, Forest Service (Forest Service), Lincoln National Forest, and Sacramento Ranger District. Upon notification of the release, the U.S. Forest Service requested that NSF remove all mercury and remediate the site.

In light of the ongoing risk presented by the unsealed structural crack and elemental mercury containment system, NSF initiated the acquisition process for specialized services under the authority cited herein.

6.104-1(a)(3): A description of the supplies or services required to meet the agency’s needs (including the estimated value).

The National Science Foundation requires specialized engineering, environmental, and technical services to assess, stabilize, and address conditions associated with the Dunn Solar Telescope (DST) and related telescope infrastructure, including the presence of elemental mercury and associated hazardous materials. The requirement includes structural evaluation, forensic analysis and reporting, development and implementation of stabilization and mitigation strategies, hazardous material management and removal, environmental compliance support, remediation activities, documentation, and related technical services necessary to ensure the safety, containment, and regulatory compliance of the site. The effort may include planning, engineering analysis, field execution, demolition of affected components, coordination with regulatory authorities, and other services within the general scope necessary to address structural stability and hazardous material risks at the site. The estimated value for these services will be $20,000,000.00

6.104-1(a)(4) An identification of the statutory authority permitting other than full and open competition.

Pursuant to 41 U.S.C. § 3304(a)(2) and FAR 6.103-2, the Government may limit the number of sources from which it solicits proposals when unusual and compelling urgency would result in serious injury to the Government if competition were not so limited.

As established in the prior section of this document, this is an active leak of liquid mercury with at least one structural crack that could result in rapid release of 18,000 lbs of liquid mercury from a great height. The risk of catastrophic failure presents an immediate threat to personnel and Government property. In addition, any such release would result in extensive contamination that would be tremendously costly to remediate in accordance with applicable regulations, given the significant detection, monitoring, cleaning, and decontamination efforts required. Due to mercury’s physical properties, it would disperse into fine droplets, spread widely, and accumulate in low points and inaccessible areas, further complicating and prolonging cleanup efforts. Time is of the essence.

Due to the highly specialized structural engineering, hazardous material containment expertise, and immediate mobilization capability required, the Government has determined that only Thornton Tomasetti can meet the Government’s needs within the timeframe necessary to prevent serious injury. Thornton Tomasetti possesses direct prior experience with comparable large-scale telescope stabilization efforts and is uniquely positioned to mobilize qualified engineering and hazardous material personnel without delay. Conducting a broader competition would result in unacceptable delays and materially increase the risk of catastrophic mercury release, risk to life and safety, and additional damage to the federal site.

6.104-1(a)(5) A demonstration that the proposed contractor’s unique qualifications or the nature of the acquisition requires use of the authority cited.

Given the active mercury leak, the unsealed structural crack(s), and the potential for catastrophic release, NSF requires a contractor that can begin work immediately with proven technical capability in both complex structural stabilization and mercury-related hazardous material management. Delays associated with identifying, qualifying, and mobilizing an alternate source would materially increase the risk of catastrophic failure and serious injury to the Government. Given the time sensitive nature of this procurement, Thorton Tomasetti is the only source that can meet the Government’s needs within the required timeframe and risk posture.

Thorton Tomasetti is the only contactor that NSF is aware of that possesses the specialized combination of forensic structural engineering expertise, experience with large scientific telescope infrastructure engineering involving extremely large telescopes, inhouse expertise in liquid mercury, and has the connections to engage all areas of the response and is available to begin working almost immediately in this remote location.

Thorton Tomasetti was a prime contractor for the response to the Arecibo telescope collapse, and they have in-depth knowledge of how to design and conduct advanced analyses for extreme events, to quantify vulnerability, identify risk and design mitigation methods. The firm has expertise regarding work at height and in supporting heavy structures (the interior telescope components held by the mercury bearing weigh approximately 200 tons) and also have a proven track record of efficient mobilization in partnership with an environmental response firm to conduct hazardous materials and waste removal.

6.104-1(a)(6) A description of efforts made to ensure that offers are solicited from as many potential sources as is practicable, including whether a notice was or will be publicized as required by subpart 5.2 and, if not, which exception under 5.202 applies.

Due to the unusual and compelling urgency associated with the active mercury leak and unsealed structural crack at the DST, NSF limited competition to the extent necessary to avoid serious injury to the Government. The immediate need to assess and stabilize the structure and prevent a catastrophic mercury release did not permit the time required to conduct a full and open competitive procurement. Given the active mercury leak, structural instability, and the potential for catastrophic failure of the telescope’s vacuum tube system, the time required to conduct competitive procedures would materially increase the risk of costly environmental cleanup within the telescope, structural collapse, and harm to personnel.

Accordingly, the delay associated with competitive procedures is not acceptable in light of the urgent and compelling circumstances described herein.

NSF considered potential sources capable of performing large-scale forensic structural analysis and hazardous materials response for complex scientific infrastructure. While other firms were contacted for limited engineering observations or hazardous materials remediation services, only Thornton Thomassetti demonstrated ability to immediately mobilize a coordinated structural and environmental response team; therefore, NSF determined that Thornton Tomasetti can meet the Government’s requirements within the required timeframe and risk posture.

A synopsis of this requirement will not be issued prior to award pursuant to FAR 5.101(b)(2), as compliance with the standard publicizing timeframes would result in unacceptable delay and increase the risk of catastrophic structural failure and a costly environmental cleanup within the telescope. In accordance with FAR 5.301 and 6.301, the required post-award notice and justification will be published.

6.104-1(a)(7) A determination by the contracting officer that the anticipated cost to the Government will be fair and reasonable.

The Contracting Officer’s signature on this document indicates that the Contracting Officer has determined that the anticipated cost to the government will be fair and reasonable. The Contractor shall be required to submit a proposal to be evaluated and negotiated by the Government. Prior to execution of the contractual extension, a proposal analysis will be carried out. The proposal analysis will ensure that the final agreed-to price for the contract action is fair and reasonable.

6.104-1(a)(8) A description of the market research conducted (see part 10) and the results or a statement of the reason market research was not conducted.

Consistent with FAR 10.001(b)(1), market research was conducted to the extent practicable under urgent circumstances. NSF considered firms known to possess experience in large-scale forensic structural engineering and hazardous materials response for complex scientific infrastructure.

Due to the active mercury leak, the unsealed structural crack, and the associated safety and environmental risks inside of the telescope, NSF did not have sufficient time to conduct extensive additional market research or issue a source sought notice prior to award. Instead, NSF relied on prior knowledge of industry capabilities, past performance information, and familiarity with firms that have performed comparable extreme-event structural response efforts involving large telescope systems.

Based on this limited but reasonable inquiry under the circumstances, NSF determined that Thornton Tomasetti has the demonstrated technical capability and immediate availability necessary to meet the Government’s requirements within the required timeframe.

6.104-1(a)(9) Any other facts supporting the use of other than full and open competition.

NSF has not identified any other facts supporting the use of other than full and open competition beyond those identified elsewhere in this justification.

6.104-1(a)(10) A listing of the sources, if any, that expressed, in writing, an interest in the acquisition.

No sources have expressed an interest to NSF in this requirement.

6.104-1(a)(11) A statement of the actions, if any, the agency may take to remove or overcome any barriers to competition before any subsequent acquisition for the supplies or services required.

The circumstances giving rise to this acquisition are associated with an emergent, hazardous condition involving the DST structure and elemental mercury containment. This requirement is driven by immediate safety and environmental concerns inside the telescope and is not expected to represent a recurring need.

NSF does not consider the current urgent action to create barriers to future competition. To the extent additional follow-on requirements arise after stabilization and remediation efforts are completed, NSF will assess the scope of those requirements and conduct market research to promote competition to the maximum extent practicable in accordance with the FAR.

6.104-1(a)(12) Contracting officer certification that the justification is accurate and complete to the best of the contracting officer’s knowledge and belief.

This justification is accurate and complete to the best of the undersigned contracting officer's knowledge.

See Next Page for Certifications and Signatures

Certifications & Signatures

Contractor Officer Certification; per FAR 6.104-1(a)(12): The contracting officer must certify that the justification is accurate and complete to the best of the contracting officer’s knowledge and belief.

In accordance with 6.104-1(a)(12), the undersigned contracting officer does certify that this justification is accurate and complete to the best of their knowledge and belief.

Kevin Giardini Date Contracting Officer Office of Chief Finanical Officer (OCFO) International Partnership Division (IPD)

Technical Certification; per FAR 6.104(b): Each justification shall include evidence that any supporting data that is the responsibility of technical or requirements personnel (e.g., verifying the Government’s minimum needs or schedule requirements or other rationale for other than full and open competition) and which form a basis for the justification have been certified as complete and accurate by the technical or requirements personnel.

In accordance with 6.104(b), the undersigned technical representative does certify that determinations that the services are “essential” are within the meaning of the cited authority, and that discussions of schedule and technical requirements are complete and accurate.

Carrie Black Date Title Office of Research Infrastructure

Approving Authority

I hereby concur with this justification for Other than Full and Open Competition

Patrick K. Breen Date Senior Procurement Executive and Division Director, Acquisition and Cooperation Support National Science Foundation

KEVIN K GIARDINI

Digitally signed by KEVIN K

GIARDINI

Date: 2026.04.22 07:46:30 -04'00'

CARRIE E

BLACK

Digitally signed by

CARRIE E BLACK

Date: 2026.04.22 08:33:09 -04'00'

PATRICK K BREEN

Digitally signed by PATRICK K

BREEN

Date: 2026.04.30 08:50:37 -04'00'