. 24/7 Space News .
SPACE TRAVEL
A QandA on the Demo-2 mission
by Jimi Russell for GRC News
Cleveland OH (SPX) Aug 07, 2020

departing now ...

When the SpaceX Crew Dragon docked with the International Space Station during the Demo-2 mission, it was a historic day for NASA and our nation as we returned the launch of American astronauts on American rockets from American soil to the orbiting laboratory. As Crew Dragon approached the space station, one thing may have gone unnoticed - a narrow rubber seal that plays a critical role in safely connecting Crew Dragon with our home in space.

We caught up with Pat Dunlap and Bruce Steinetz who led efforts at NASA's Glenn Research Center in Cleveland to develop a new, robust seal for the Commercial Crew Program (CCP) and other future spacecraft.

Can you give us a little history of the seal development leading up to its selection for the Commercial Crew Program?

Bruce: NASA's Johnson Space Center (JSC) approached us a little over 15 years ago, requesting our expertise to help develop a new seal for what would become the NASA Docking System (NDS). This system is compliant with the International Docking System Standard (IDSS) and has become a standard design for future American or international spacecraft (e.g. ESA (European Space Agency) and the Japanese Space Agency) to dock with the space station, supporting the international charter of the laboratory.

We developed several designs of the docking system seal for JSC and developed full-scale test hardware to evaluate the seals under representative operating conditions. Eventually, as we matured our design, we worked as a team with Boeing, the prime contractor for the NDS, to evaluate the final seal.

Why are these docking seals important?

Pat: These seals prevent breathable air from escaping through the connection between the visiting spacecraft and the station. This connection is a heavily loaded somewhat dynamic structural interface and the seals must perform flawlessly during docking approach and while docked to the ISS. Because they're orbiting 250-plus miles up, and the visiting spacecraft can stay docked months at a time, it's critical that the seals have very low leakage to minimize the amount of make-up supply air needed to maintain cabin pressure on the laboratory.

The seal we developed is a little over four feet in diameter, which is large enough to allow the crew and some cargo to transfer from the visiting spacecraft to the station. The seal has two redundant sealing surfaces or interfaces and had to be narrow enough to fit in the limited space available on the docking interface. It also had to be strong and resilient to withstand the extreme environment of space. Through development testing on the ground, we were able to prove that our design leaked less air per day than what would fill a standard pop can (about 12 oz or 330 ml). That is a really low leak rate for a seal of that size that also has to survive the challenging environment of space.

What were some of the seal design challenges that had to be addressed?

Pat: We had to evaluate the seal at every possible condition - both environmental and mechanical - that it would experience during flight. We also had to look at reusability.

We chose to make the seal out of silicone, a rubber-like material that can withstand the extreme temperatures experienced in space. It also had to survive exposure to damaging ultraviolet rays that are more severe on orbit than on the ground, without the leak rate increasing significantly. The seal material also couldn't be overly sticky so it wouldn't adhere to the metal sealing surface on the station side of the connection.

We tested multiple, smaller versions of different designs first to make sure they met all the requirements before testing full-scale versions of the final seal design for the docking system. Prior to the flight with SpaceX, we also tested small prototype seals in space, including some that were on the station for more than 18 months. Those prototypes were exposed to the harsh environment of space and were then brought back for additional testing.

How did you work with SpaceX to use this seal?

Bruce: The team at SpaceX developed their own unique docking system for Crew Dragon, but it needed to be compatible with the docking systems on the station. They worked with our counterparts at JSC to make sure the docking system worked with the interface standard and used some of the original NDS hardware, including our seal. The seal was first launched into space in March 2019 on SpaceX's uncrewed Demo-1 mission, during which it worked well.

Who else worked on this with NASA Glenn?

Bruce: We've worked with many outstanding partners on this project for the last 15 years with support from JSC. We worked locally in Cleveland and around Ohio with commercial partner Vantage Partners, LLC., who supported the detail design and test hardware development phases.

We also had great contributions from the University of Akron, the University of Toledo, and the Ohio Aerospace Institute. Those team members were instrumental in the concept formulation and in the development and testing of candidate materials and seals.

We selected Parker Hannifin's Composite Sealing Systems Division in San Diego to fabricate the seals for NASA and our spaceflight partners. It is noteworthy that sufficient funding was provided to Parker which allowed them to procure a large press to mold the seal in one operation. This approach eliminated joints in the seal that had been problematic during development of earlier space station seals.

What does it feel like to see something you've worked on for so long finally being used during a historic mission like SpaceX Demo-2?

Bruce: It is exhilarating to see all of our team's hard work pay off and contribute to such a historic mission! As one of the agency's research centers, NASA Glenn often has the opportunity to work on advanced technologies, but many of them don't get selected for flight. This is one of those very fortunate times where we had a good idea and were able to carry it through the many twists and turns of the development process and see it fly and become standard bill-of-equipment for future flights.

Pat: I've been lucky enough during my career at NASA to work on several projects where the seal we developed actually ended up flying. It's always rewarding to see something that you worked on help contribute to the success of a mission like this.

What's next for your team?

Pat: We plan to continue to work alongside SpaceX and the CCP to make sure the seal works well for upcoming missions, including for Boeing's CST-100 Starliner spacecraft. Future Artemis missions on the Orion spacecraft will be using the NASA Docking System, and the human landing systems for the Artemis program are looking into using it, too, when they land the first woman and next man on the Moon.

With that in mind, we're also starting a new project to evaluate the effects of lunar dust on seal performance and working on ways to make the seals more dust tolerant. We're excited that our seal will help enable all of these future missions!


Related Links
Commercial Crew Program
Space Tourism, Space Transport and Space Exploration News


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


SPACE TRAVEL
Power, bones, bubbles and other Weightless action on the Space Station
Paris (ESA) Aug 07, 2020
European science progressed at a slower pace on the International Space Station in the past month. As a series of spacewalks to power up the space habitat came to an end and two of its passengers left for home Earth, intriguing bubbles puzzled researchers and left them wanting to know more. b>The longest foam br> /b> More bubbles, please. The Space Station has witnessed the longest science run with foams for the Foam-Coarsening experiment. This research mixed varying amounts of water and soap in ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

SPACE TRAVEL
A QandA on the Demo-2 mission

Power, bones, bubbles and other Weightless action on the Space Station

Roscosmos teases names of next year's ISS tourist group flight

Take Me to Mars

SPACE TRAVEL
Russia wants to return to Venus, build reusable rocket

SpaceX completes test flight of Mars rocket prototype

SpaceX launched 10th Starlink batch

Spaceflight and Benchmark sign green propulsion deal for Sherpa launcher

SPACE TRAVEL
NASA scientists leverage carbon-measuring instrument for Mars studies

Rice researchers use InSight for deep Mars measurements

NASA's MAVEN observes Martian night sky pulsing in ultraviolet light

Lava tubes on Mars and the Moon are so wide they can host planetary bases

SPACE TRAVEL
China seeks payload ideas for mission to moon, asteroid

China marching to Mars for humanity's better shared future

From the Moon to Mars: China's long march in space

Tianwen 1 probe to soon blast off for Mars

SPACE TRAVEL
Exolaunch awarded contracts to deliver Swarm Satellites into orbit on Falcon 9

SES selects SpaceX for launch of new C-Band satellites

SES selects ULA to launch two C-Band satellites to accelerate C-Band clearing

Hisdesat And XTAR Complete Transaction For XTAR-EUR Satellite

SPACE TRAVEL
Scientists find way to track space junk in daylight

At Aerospace: How Internships Went Virtual

First laser detection of space debris in daylight

Transforming e-waste into a strong, protective coating for metal

SPACE TRAVEL
Hubble uses Earth as a Proxy for identifying oxygen on exoplanets

VLBA finds planet orbiting small, cool star

Surprisingly dense exoplanet challenges planet formation theories

Deep sea microbes dormant for 100 million years are hungry and ready to multiply

SPACE TRAVEL
Ammonia sparks unexpected, exotic lightning on Jupiter

Shallow Lightning and Mushballs reveal ammonia to Juno scientists

NASA's Webb Telescope Will Study Jupiter, Its Rings, and Two Intriguing Moons

NASA Juno takes first images of Ganymede's North Pole









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.