42

To reduce the force of the impact on landing the heat shield was designed to separate and be held on by a skirt that acted as an airbag. From the NASA list of Mercury illustrations: Figure 46: Impact attenuation When the heat shield was released the impact skirt would fill with air, but when the heat shield hit the water the air being forced out the holes ...


31

It wasn’t originally intended for the astronauts to be matched 1-to-1 with the flights; four additional crewed Mercury-Redstone (suborbital) and three more Mercury-Atlas (orbital) flights were planned but canceled. The additional suborbital missions were canceled to put a man in orbit sooner, and the last orbital missions were canceled as NASA shifted focus ...


26

I'll preface my answer with the comment that it was a different time and the way that experimental animals, even primates, were treated was different than today. tl;dr the chimpanzee was trained to press levers upon the illumination of light signals to avoid receiving electrical shocks. Details follow: Subject 61 (aka Ham for Holloman Aerospace Medicine) got ...


23

Yes, visiting some of the famous (American) capsules is possible. Larger accumulations of capsules, excluding mock-ups and never-flown equipment, can be found at the following places in the US. National Air and Space Museum (Smithsonian Institution), Washington, DC: Mercury-Redstone-3 [suborbital], "Freedom 7" (Shepard) Mercury-Atlas-6, "Friendship 7" (...


22

To my knowledge, only two of the candidates that failed the tests did later become astronauts and flew on missions for NASA: Jim Lovell According to the Wikipedia article on Project Mercury: Navy Lt (later Capt) Jim Lovell, who was later an astronaut in the Gemini and Apollo programs, did not pass the physical tests. Lovell flew on 4 different ...


21

Alan Shepard is 1.80 John Glenn is 1.79 To quote Mercury Seven wikipedia page: Because of the small space inside the Mercury spacecraft, candidates could be no taller than 5 feet 11 inches (180 cm) and weigh no more than 180 pounds (82 kg). Now, to your question: when did that end? the answer is: it didn't. The requirements have been just ...


20

In the Apollo era, landing guidance had gotten quite precise and there wasn't a "huge flotilla" waiting; Apollo 8's recovery force was the largest, with 6 ships waiting for it in each of two landing zones, but groups of 2-3 were more common. The recovery ships were usually positioned a couple of miles away from the designated landing point, and the ...


18

The Mercury selection process started on February 2, 1959 with the first meeting at the Pentagon, so I will keep 1959 as the rank evaluation year, which results in the following ranks. (*) denotes some uncertainty in the rank (see remarks below the table). Name Branch Rank in 1959 PG Date of birth 1. Malcolm Scott Carpenter Navy Lieutenant* O-3 May 1, 1925 ...


17

You are referring to the materials protecting from insulation and the outer layers of space suits. Look carefully, they have not seen much change since the Apollo era. In Mercury, the suits were still at an rather early stage of development. They were intended as pressure-suits protecting the astronauts from decompression in case there was a leak in the ...


15

Project Mercury used imperial units of measure. For example, the Mercury spacecraft main instrument panel indicated altitude in FT (feet):        The Mercury spacecraft main instrument panel from Project Mercury Indoctrination, May 1959 (Source: NASA. Click for full size) They used statute miles as a measure of distance in ...


14

I am unsure if this reference is tight enough for your criteria, but this article written by Ben Evans at AmericaSpace appears to have a detailed accounting of the launch. Unfortunately, I cannot find what Mr. Evans's references for the accounting are. In any case, the article is highly entertaining. There's a paragraph towards the bottom of the article ...


13

Understanding of re-entry heating at the time led to that decision. Around the time that Mercury was being designed, there was a huge problem in the field of ballistic missile design (which had a sister problem in the field of spacecraft design): at hypersonic speeds the noses of ballistic missiles would melt. The original thinking at the time was that the ...


11

The Post Flight Mission Report for Grissom's flight compares key parameters for the two manned suborbital missions (Shepard's MR-3 and Grissom's MR-4): The corresponding document for John Glenn's orbital flight gives its orbital velocity. Assuming the Glenn number is inertial velocity, the percentages are 28.7% and 29.5%. In metric figures, MR-3 reached ...


11

The Apollo 10 Command Module is on display at the Science Museum in London. (pic from beenthere-donethat.org.uk)


11

According to NASA's mission report on Mercury-Atlas 6, the following ground stations in the Mercury network offered voice communication and spacecraft telemetry (in order of eastward travel): Atlantic Missile Range (i.e. Cape Canaveral) Bermuda Mid-Atlantic Ship Canary Islands Kano, Nigeria Zanzibar Indian Ocean Ship Muchea, Australia Woomera, Australia ...


10

(This is adapted from my question/answer at Day-to-day tasks of human computers, ala Hidden Figures movie - History of Science and Mathematics Stack Exchange) I was also fascinated by the film Hidden Figures, and a related article from New Scientist magazine "Gifted and black: The brilliant woman who got the US into space". Compressible Flow In the ...


10

This was to test the change in the chimp's reaction time from the ground to space. It was a human analog experiment--i.e. the results of the test were used to make estimations of how human reaction time would change in spaceflight. Ham's average reaction time on the ground was .8 second, and during flight he averaged .82 second. The assessment was that he ...


10

On the left in front of Cooper & Grissom is, I believe, a model of an Agena rocket stage, used as the basis for the Gemini-Agena Target Vehicle, which was the uncrewed rendezvous-docking target for some of the Gemini missions. This photo, from 1963, is over two years before the GATV flew, so doesn't reflect the final design. Here's a diagram of the GATV ...


9

These are vernier thrusters! They're small (relative to the main engine) rocket engines used to finely control the heading and alignment and form part of the Mercury-Atlas' attitude & roll control system. These days, systems tend to use gimbaling of the main motor to maintain attitude control; but if you couldn't gimbal, introducing changes in the ...


8

To my knowledge, Mercury Project used keyed CWI (Continuous Wave Interrupted) FM (frequency modulated) system, or FMCWI, capable of receiving Morse code over the UHF (Ultra High Frequency) and voice over HF (High Frequency) channels. This would be a completely analogue system, so we can't really speak of cryptographic algorithms. That doesn't mean comms were ...


8

During Project Mercury, NASA's communication network was new, and many of the ground stations did not have dedicated voice communications links back to Houston, so each site needed its own CAPCOM, as described in this QA. During Gemini the network was upgraded; many of the ground stations could provide direct voice links to Houston, but others could not, as ...


8

The goal of Project Mercury as stated in 1958 was to put a man into orbit safely. In order to do that, NASA wanted to send animals, first. The Russians had done exactly that, and NASA preferred using a chimpanzee instead of a dog. The X-15 had to be piloted, you couldn't put an animal into it. Thus, the Mercury capsule was needed to put a chimpanzee into ...


8

Al Worden’s 1971 Corvette and Alan Bean’s 1969 Corvette When it comes to information on Corvette, it's best to take a gander at the Corvette Museum has to say. Starting with Alan Shepard and the Freedom 7 capsule launch on May 5, 1961 to the final flight of Apollo 17 on December 11, 1972, GM wanted it's sports car to be associated with NASA. So they made a ...


7

He was not exactly a Mercury washout, but Deke Slayton was selected as one of the original Mercury 7, and was scheduled to take the fourth Mercury flight (second orbital, following John Glenn) but was grounded due to a heart condition. He famously went on to become chief of the astronaut office, being responsible for crew selection throughout Gemini and ...


7

This article on health concerns for space tourists includes a photo of Wally Schirra performing the lung capacity test: . He appears to be blowing into a tube but it's unclear if there's a ball balancing somewhere, and by all appearances he's being tested solo. I'd be very surprised if such tests were ever administered to a group at once.


7

All of the Apollo Command Modules are on display as follows: Apollo 6 - Fernbank Science Center, Atlanta, Georgia Apollo 7 - Frontiers of Flight Museum, Dallas, Texas Apollo 8 - Chicago Museum of Science and Industry, Chicago, Illinois Apollo 9 - San Diego Air and Space Museum, San Diego, California Apollo 10 - Science Museum, London, England ...


7

They did slow the capsules down, and, thereby, cause the thermal loads on their heatshields to be lower and their splashdown points to be closer to the Cape, but the Mercury heatshield could easily withstand far higher heating loads than these (given that it would have to protect the Mercury-Atlas capsules during reentry from full orbital speeds - and ...


6

Apollo had an onboard guidance computer, with its own clock. From Wikipedia: The AGC timing reference came from a 2.048 MHz crystal clock. The clock was divided by two to produce a four-phase 1.024 MHz clock which the AGC used to perform internal operations. The 1.024 MHz clock was also divided by two to produce a 512 kHz signal called the master frequency;...


6

The rest of the current American crewed capsules. Mercury Capsules MR-3 Freedom 7 | JFK Library, Boston, MA MR-4 Liberty Bell 7 | Kansas Cosmosphere and Space Center Hutchinson, Kansas MA-6 Friendship 7 | National Air and Space Museum Washington D.C. MA-7 Aurora 7 | Museum of Science and Industry Chicago, Illinois MA-8 Sigma 7 | Kennedy Space Center ...


6

NASA probably learned a lot of lessons following the development of Gemini. Astronaut Gus Grissom (170cm) was instrumental in the cockpit layout and design, and they even nicknamed the spacecraft the Gusmobile, since it's rumoured he was the only one able to fit into it (I read somewhere that it wasn't just Gus who fit, but that a majority of the original ...


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