The recent announcement by NASA that there is evidence of salty, liquid water seeping out of the ground on Mars is both exciting and scientifically puzzling at the same time. As a member of the science team for the High Resolution Imaging Science Experiment (HiRISE) camera on board the Mars Reconnaissance Orbiter (MRO), I’ve been hearing about these possible seeps, or Recurring Slope Lineae (RSL), for several years now.
The RSL are relatively darker, small (5 meters or less across), streaks that appear during the warm season on Mars, expanding downslope for a time, before fading as colder conditions set in later in the year. The atmosphere on Mars is very low density compared to Earth. As a result, surface temperatures and pressures are also relatively low, thereby making conditions enabling the occurrence of liquid water difficult to envision. So while the possibility that the RSL are the result of water seeping out of the ground appears consistent with their occurrence and form, how this might happen has been much harder to explain.
Nevertheless, a paper published in the journal Nature Geoscience on September 28 of this year (Ojha et al.) reports that data from HiRISE and the Compact Reconnaissance Imaging Spectrometer for Mars instrument, also onboard MRO, from four different RSL locations reveals hydrated salts are present when the features are most extensive. As reported in the paper, these salts, probably occurring as perchlorate and chlorate, are interpreted to strongly support the interpretation that the RSL are the result of liquid water at the surface.
The discovery is exciting because it means the liquid water survives at and just beneath the surface of Mars today. Could this also mean that conditions that might be habitable also occur? Moreover, access to liquid water for astronauts traveling to Mars in the future means that vital resource may not have to be carried with them from the Earth. That would help reduce and/or free up some of the payload required to get to Mars.
The presence of these salts suggests the water is a brine and helps explain how it could remain liquid under present surface conditions. However, it does not solve the mystery of why the water is where it is or how it got there. If the RSL are related to groundwater seepage, it is not certain why they occur where they do versus where they do not. For example, some occur on the sides of the central peak of an impact crater named Horowitz which is a mountain of sorts that is isolated from rocks outside the crater. So how does the water get there? Why do they occur on some slopes, but not on others relatively nearby? So while the evidence points strongly to the RSL being due to seeps of briny, liquid water, a number of mysteries about their formation and occurrence remain to be solved.
The RSL continue to be the target of study and new data from MRO will undoubtedly lead to additional hypotheses and interpretations regarding their origin so stay tuned!
John Grant is a geologist in the Center for Earth and Planetary Studies at the National Air and Space Museum. He is a member of the Science Team for the Mars Science Laboratory Curiosity, Mars Exploration Rover Opportunity, and HiRISE camera on the Mars Reconnaissance Orbiter. He also co-chairs the community process of selecting the landing sites for the Mars 2020 rover.
In a way, every day is Ask An Archivist Day. The National Air and Space Museum Archives receives queries from our online request form at every hour of the day from all over the world. But October 1 marks the beginning of American Archives Month, in which archival institutions throughout the United States celebrate their holdings and the work archivists do preserving, cataloging, caring for, and making accessible our history. To kick off this month of events, archivists around the country are taking to Twitter to respond to questions tweeted with the hashtag #AskAnArchivist.
From 1:00 pm to 2:00 pm on Thursday, October 1, Elizabeth Borja and Brian Nicklas (EDIT: Brian Nicklas will no longer be available to answer questions) from the Archives will be on the Museum’s Twitter account and eager to respond to any and all questions you have about archives, archival work, and archivists themselves. Just tweet @airandspace and add the hashtag #AskAnArchivist!
Please be aware that there may be some questions that will require too detailed an answer for us to complete within the limits of the 140 character Twitter format. For example, what drawings and manuals do you have for the P-51 Mustang? For a question like this, we would need to create a custom search order form for you. Also, some questions may require additional research in our collections. For these queries, we may refer you to our online request form. We’ve also answered many basic questions about our collections on our FAQ. These notes aside, no question is too serious or not so serious! Let’s get a head start….
Serious Question: How did you come to work at the National Air and Space Museum?
Every staff member has his or her own story. I (Elizabeth Borja) was an undergraduate majoring in History and Biology when I took a student job at an archival repository at my university. I already enjoyed research in primary sources as part of my history program. While processing and arranging historical documents at the archives, I discovered them in a new light. I then completed a dual Master’s program in History and Library Science, with a concentration in archives and records management. As an employee of History Associates Incorporated, I established and maintained the archives for the History Office of the Department of Homeland Security. I’ve been with the National Air and Space Museum for six years now as the reference and outreach coordinator.
My colleague, Brian Nicklas, attended the Aeronautical Studies program at Embry-Riddle Aeronautical University. He then returned to Washington, DC, and continued to write freelance aerospace articles. He was in the National Air and Space Museum’s Archives so frequently to do research, he was asked to volunteer and then to apply for an upcoming opening. Over the past 27 years with the Museum, Brian’s background in both air and space topics has helped him to work between aerospace professionals on the outside and our collections. Recently, Brian authored American Missiles: The Complete Smithsonian Field Guide.
Together, Brian and I are the main reference staff for the Archives. We are the voices that answer the phone when you call, the names you will see signed at the bottom of the letters accompanying responses to research queries, and the faces you’ll see in the reading room or at Museum events such as Innovations in Flight Day, Women in Aviation Family Day, or the Steven F. Udvar-Hazy Center Open House.
Not So Serious Question: If your archives had a soundtrack, what songs would be on it?
I could probably make an archives-related playlist from Traveling Wilburys songs alone. Handle with Care is exactly how one should work with archival materials. Cool Dry Place is the ideal location one should store archival collections. Wilbury Twist is what an archivist does when trying to get a box off a tall shelf onto a cart while standing on a ladder, and if she’s not coordinated, it’s the End of the Line.
Serious Question: How does the Archives staff interact with the rest of the National Air and Space Museum?
Our collections span the history of flight from ancient times to the present day and we do try to collect materials related to artifacts in the overall Museum collection. Archivists work closely with museum curators, restoration specialists, exhibits designers, special events coordinators, and education specialists to provide materials that will help them with whatever they need. For example, the Archives have provided drawings that have helped restoration staff not only create new parts for aircraft in the Restoration Hangar but to get an airplane through the Museum and into an elevator. Much of the material in the Hawaii by Air exhibition came from the Archives collections. Chief of Museum Learning Tim Grove spent many hours in the Archives preparing for the Pioneers of Flight gallery and was inspired by his research to write First Flight Around the World, a children’s book about the Douglas World Cruiser.
Not So Serious Question: What is the funniest thing you’ve found in the Archives?
From snowman caricatures of Austro-Hungarian Emperor Franz Joseph I and Germany’s Kaiser Wilhelm II to World War I era bunny ears, there are definitely moments of levity in our collections. My favorite may be a photograph a researcher found of Orville Wright getting a piggyback ride. According to the documentation that accompanied the photograph, Orville often went out to fly in business clothes and shoes, whereas the mechanics wore hip boots. This test flight of a flying boat had landed in Ohio’s Miami River, so a mechanic carried Orville piggyback-style and put him in the plane so he wouldn’t get his feet wet.
We look forward to seeing what you #AskAnArchivist!
Elizabeth C. Borja is an archivist in the National Air and Space Museum’s Archives Department.
You may have heard about the “supermoon eclipse” that will happen this Sunday, September 27. Sounds pretty exciting! But what does it mean?
Let’s start with the “supermoon” part. The Moon’s orbit around the Earth is not a perfect circle; it’s an ellipse, which means that the distance between the Moon and the Earth changes over the course of a month. When the Moon is in the part of its orbit that brings it closest to Earth, the perigee, it appears larger in our sky. A full Moon that occurs during perigee is known as a “supermoon” in popular culture because it looks bigger.
But don’t worry, you won’t need your sunglasses at midnight. A supermoon appears only 14% wider and 30% brighter than a “micromoon,” when the Moon is at apogee, the farthest point in its orbit. The difference between perigee and apogee is just 48,280 kilometers (30,000 miles), which sounds like a lot until you realize that’s a mere 12% of the average distance from Moon to Earth.
Enough with the numbers, let’s see how it looks! Here’s a visual comparison that was featured as NASA’s Astronomy Picture of the Day in 2014. This image consists of two photos taken by Stefano Sciarpetti, with a micromoon shown in front of a supermoon. See the size difference? It’s not much, and it’s really hard to notice when you’re standing outside looking at a Moon suspended in an ink black sky.
But still, it’s fun to know that we will have a supermoon during this weekend’s total lunar eclipse! This one is the last in a series of four eclipses that have been spaced six months apart over the past two years. After this Sunday, there won’t be another total lunar eclipse until 2018! And unlike some recent eclipses that happened at ridiculous hours of the night, this one is nicely timed in the evening from about 9:00 pm to 12:30 am EDT, with totality (when the Moon is entirely within the Earth’s shadow) from 10:11 pm to 11:23 pm EDT. The supermoon eclipse will be visible from most of North and South America, Europe, and Africa. For any young children in your life, our Science in Pre-K educators wrote up this great conversation about the eclipse.
If you’ll be near the Museum that night, stop by our Phoebe Waterman Haas Public Observatory to view the eclipse with us! We will be open from 8:00 pm to midnight, weather permitting, with our telescopes pointed at the Moon and other fun astronomical sights. Check the Observatory’s Twitter feed the day of the event for closure notices and weather updates.
Shauna Edson is an astronomy education specialist at the National Air and Space Museum
The new Boeing Milestones of Flight Hall has to be one of the most challenging spaces that an exhibition team could design. It has multiple conflicting functions. As the entrance to one of the world’s busiest museums, it must accommodate millions of visitors each year. In some ways it’s a giant hotel lobby, a sorting chamber where people go in many directions and must be able to quickly figure out how to get to where they want to go. Signage must be excellent. The welcome desk, or concierge desk to keep the hotel analogy, must be easy to find with clear sight lines to indicate its location.
The Hall must also serve as an introduction to the Museum. Although we don’t have an official orientation area, we must somehow convey the themes and content of the rest of the Museum in a way that will excite visitors about the prospect of exploring our more than 21 exhibition galleries. We must offer a taste of the stories that we tell and the historical people that visitors will find throughout the Museum.
The Milestones of Flight Hall was designed to be awe-inspiring and must continue that tradition. It features some of the Museum’s most popular artifacts, from the Spirit of St. Louis, to the Bell X-1, and the first American jet airplane, the Bell XP-59A Airacomet. We are definitely keeping those in place and upping the power punch with the addition of the Apollo Lunar Module and an addition sure to make a certain group of visitors very happy, the Starship Enterprise studio model from the Star Trek television series (1966-1969). Any of these artifacts could easily be the star of its own exhibition. One iconic artifact that once hung front and center in the Hall, was the 1903 Wright Flyer. Museum staff moved it into a temporary exhibition, The Wright Brothers & The Invention of the Aerial Age, to celebrate the centennial of flight. The exhibition presents the airplane at eye level and tells the rich and fascinating story of the artifact. The exhibition proved so popular that it became a long-term exhibition.
And thus one of the main challenges of the space: How much information can we include about each icon when each one could fill their own exhibition? As an educator, I want to engage people with each artifact’s story, to provide historical context, and to offer various interactive experiences sure to keep visitors engrossed for a long time. Yet, remember the sorting chamber? People can’t stay too long because more people will be coming and going through the doors. Finding the right amount of information is a huge challenge. There is much historic video footage to include with each artifact. We want to show each one in action. Then there is the challenge of the natural light pouring in from above. I love the natural light in the space, but it is not terribly conducive for video displays.
To help layer information, the Milestones of Flight team has developed a digital wall, text panels with labels, video, and a new mobile experience. Labels will encourage visitors to make connections, to meet some of the many people in history who interacted with the artifacts, and to look closer at how the artifacts are designed.
On top of all of these challenges, the space is used many times each year for special evening events. It’s transformed by night into an appealing venue for dinners and programs. It can accommodate about 400 seated guests, a stage, and room for live music. Its layout must be flexible to accommodate these functions.
Meeting the demands of the space has required numerous meetings and long discussions. In the end, we hope to meet those challenges and find balance so that the Boeing Milestones of Flight Hall can continue to inspire each visitor to look up and marvel at the gleaming machines that have soared into the sky.
Tim Grove is chief of Museum Learning at the National Air and Space Museum.