NIST Experts Help Preserve 250 Years of American History

As we celebrate the United States’ 250th anniversary this year, NIST experts are working to preserve our nation’s history for the next 250-plus years. Among other historic preservation efforts, NIST engineers and scientists created a bespoke time capsule with artifacts from around the country. As required by law, the time capsule will be buried in Philadelphia on July 4, 2026, and should remain underground until 2275.

This is a formidable challenge, but luckily, NIST experts have extensive experience in historic preservation. Our researchers have helped preserve the Declaration of Independence, the Magna Carta and many other artifacts in the last few decades.

Taking Measure interviewed some of the researchers working on these efforts, including Fabrication Technology Office chief Michael Berilla, mechanical engineers Jay Nanninga and Jacob Ricker, and research chemist Jay Hendricks.

Tell us a bit about what NIST is doing to preserve important American historical artifacts.

Michael Berilla: Right now, we’re doing three major preservation projects.

• We’re working with the Library of Congress, the National Park Service and the America 250 Commission to create a time capsule in honor of America’s 250th anniversary this year.
• We’re also helping Westchester County, New York, encase its copy of the Declaration of Independence, known as the Holt broadside. The Holt broadside is one of the copies of the Declaration of Independence that 18th-century newspaper publisher John Holt prepared for government officials throughout New York. While 500 copies were made, only five are known to have survived. We’re creating a custom encasement designed to protect the document so that it can remain on display for the public at the Westchester County Archives.
• Our third project is helping the Library of Congress research how materials degrade in different environments. We’re creating a test capsule that will speed up the natural degradation of books and papers, so their experts can learn even more about preserving documents for very long-term storage.

What does the Philadelphia time capsule look like?

Berilla: The time capsule is a tube that’s less than a meter in diameter and height. It’s about two feet in diameter and three feet tall. The capsule is made of stainless steel. It’ll be about 400 kilograms (or 900 pounds) when finished. Inside, the capsule has stackable, small shelves to hold the stored items.

We designed a bell jar that sits on top of the time capsule. That bell jar is even heavier than the capsule itself. It will naturally trap air, and the air inside pushes out anything trying to get in. The most important thing we need to keep out is water, as that would damage or destroy the items inside. Philadelphia would have to be almost two meters (six feet) underwater for water to enter this chamber.

Jay Hendricks: Many years ago, before there were dive suits, people would go underwater using a bell. The diver would basically stand underneath it and breathe in a pocket of air. You can test this by submerging a glass of water in a bathtub. If you push it down, you see the bubbles stay there in the glass. It’s a similar type of physics we’re designing around here.

What’s going inside the time capsule, and how did that affect the design?

Berilla: Some of the items in the time capsule include crystals from the New Year’s Eve ball drop in Times Square, a signed joint letter from Congress, books, a cellphone, a coin-toss coin from an NFL game and a message in a bottle.

Additionally, each state and territory submitted a variety of papers and small items that represent the locality. Nevada provided gaming chips, for example, while Michigan sent its famous Petoskey stones. The Northern Mariana Islands provided a locally crafted glass bead necklace and a clamshell.

Jay Nanninga: We have high-quality documents to put in the time capsule, along with items that could damage them. The gavel, for example, might be covered with varnish that could wear off on the papers over time. So, experts at the Library of Congress have been very helpful in determining which types of boxes to use for the different items. Then, we created a secondary container for even more protection of the documents.

Hendricks: Stainless steel hasn’t been around long enough for it to be buried for 250 years. We assume it’ll fare better than regular steel, but we don’t know for sure. So having multiple layers of containment is so important. We feel confident that the innermost container will survive the test of time and exposure to the elements.

What is your role in the Library of Congress study on the aging of documents?

Nanninga: For this study, we created a low-oxygen chamber, known as an anoxic chamber, that the researchers will use to speed up the aging of documents. It’s a tube with a quartz viewport at one end. So, they can attach a laser and a laser sensor, then shine it inside at the document they are “aging.”

How is NIST assisting in preserving the Holt broadside for Westchester County, New York?

Jacob Ricker: The easiest way to preserve a document is to put it in a dark room where no one can see it. But that’s not what we want to do here. We want to create a case that people can use to view the document, and that’s a challenge. Our research group has expertise in making vacuums (creating tight seals) and sensors.

So, we're working with the local preservationists in New York to seal the environment of the document encasement. We’ll pump in argon gas, along with some humidity. This allows us to keep out an excessive amount of oxygen, which could dry out the document and make it brittle.

But our work doesn’t stop there. We’ll have many sensors that will monitor all aspects of the environment inside that encasement. If there’s a significant change in weather pressure, for example, that could cause a leak, and we don’t want that. We have a small computer inside the encasement that continuously records important data about its environment. The computer will alert the preservationists if there’s an issue. We can investigate and see what to do from there.

Why is NIST the best organization to preserve so many historic artifacts?

Nanninga: I think the variety and depth of expertise is what makes NIST successful. I would be challenged to find a machine shop that has a gas specialist and a vacuum specialist just down the hall. We have the right people at NIST who have the skills to take on these complex projects.

What does it mean to you to be a part of preserving American history?

Nanninga: I was a construction worker in my previous career before returning to school to become a mechanical engineer. I had the opportunity to come to NIST, and it was life-changing. I now have this fairy-tale design job that continues to amaze me every day. I tell my wife about what I’m doing, and she’s amazed by the work that this whole office does.

Berilla: I completely agree with that. I feel like every few months, we’re coming up with a new project that’s so new and interesting to be a part of. I have three young kids, and when I tell them about this, they understand it and think it’s cool. So, the idea of being a part of something historical that represents the entire country is really exciting.

Ricker: This is one of the things I love most about working at NIST. Every day, we get to work on exciting projects. We get to do some of the coolest research in the world, and to honor our country like this, it’s just a wonderful opportunity.

Hendricks: It’s been incredibly rewarding to work on all of these types of efforts over the years. It’s so fun to walk into a museum and say, “You know what, I helped put that together.” To use the science and technology that we studied in school and practice here in our lab to do something as meaningful as preserving our country’s history, it’s such an honor to be a part of that.

Behind the America250 Time Capsule (Captions)