Science and Nature

Did Static Electrical energy — No longer Gus Grissom — Blow the Hatch of the Liberty Bell 7 Spacecraft?

The myth that a pioneering astronaut lost his nerve at the cessation of his first lag to living 60 years ago — which resulted in the loss of his spacecraft and his terminate to drowning — stains the ancient past of U.S. human spaceflight.

On July 21, 1961, the U.S. launched its 2nd human into living, advancing Mission Mercury, The USA’s response to Soviet living domination. The 15-minute suborbital flight by astronaut Gus Grissom went off with out a hitch. Grissom skilled about five minutes of weightlessness, examined an improved autopilot, peered via a big spacecraft window to invent navigational observations, and in the kill splashed down in the Atlantic Ocean.

The Mercury astronauts had lobbied for a like a flash-exit exploding hatch for his or her craft. Grissom’s would possibly possibly be the most most principal flight to test that hatch invent. After splashdown, the pointers known as for him to deploy recovery aids, which integrated a whip antenna accepted to inform with coming advance recovery helicopters. A backup helicopter filmed vital of the recovery sequence.

Once a recovery helicopter bent onto his spacecraft, the knowing became for Grissom to arm and detonate the exploding hatch. A sling would be lowered, and he would be hoisted aboard the recovery helicopter because it hauled each man and machine relief to a recovery ship.

Then all once more, things didn’t plug in step with knowing. The recovery of Grissom’s ship, dubbed Liberty Bell 7, would change into basically the most perilous phase of his flight. As the recovery personnel approached, the spacecraft’s hatch upfront blew, forcing Grissom to abandon his flooding capsule. This left him struggling in the ocean for several minutes as his spacesuit took on water. Grissom survived the ordeal. But a myth that he blew the hatch early, causing Liberty Bell 7 to sink into the ocean, began to build.

The loss of Liberty Bell 7 — the worst thing that can also happen to an astronaut, attempting death — dogged Grissom and his family for the the rest of his transient life. Grissom, who went on to assert the maiden flight of project Gemini earlier than he perished with his two crewmates in the Apollo 1 hearth in 1967, referred to the ordeal because the “hatch crap.”

But if Grissom didn’t deliberately and even unintentionally bump the armed hatch detonator, what precipitated Liberty Bell 7’s hatch to blow?

NASA managers, anxious to plug on to John Glenn’s orbital flight, tried however failed to identify the true motive of the so-known as premature hatch actuation. They merely revised recovery procedures to specify the hatch needs to be armed after the helicopter hooks onto the spacecraft. In doing so, they exonerated themselves from lacking a key mission aim: qualifying (human ranking) the flightworthiness of the explosive hatch. Given the failure to fulfill that mission aim, we and others contain picked up the thread, analyzing stipulations at the positioning where the incident befell — stipulations on the day of the flight that NASA investigators were unable to repeat.

In accordance to contemporary digital image enhancements and a re-examination of the ancient file, it is our competition that the 2nd American to flee in living, U.S. Air Power Col. Virgil Ivan “Gus” Grissom, didn’t — and became no longer capable of, by practising and temperament — effort at the cessation of his otherwise winning flight. That sage has persevered for decades, superior by the creator Tom Wolff in his e-book and the movie, The Trustworthy Stuff.

We post a markedly different interpretation of the flight of Liberty Bell 7 and its conclusion, in accordance with a frame-by-­frame re-examination of the most effective-quality transfer of the unusual recovery photos, kindly supplied by archivist Stephen Slater. The digital imaging ways we contain utilized to this movie cowl principal aspects beforehand unavailable. They verify the recollections of the person closest to Grissom’s spacecraft at the excessive 2nd: U.S. Marine Corps Lieutenant John Reinhard, who became located at the aspect door of the prime recovery helicopter. Our enhanced photos has even jogged the memory of any other eyewitness, U.S. Marine Corps Lieutenant James Lewis, pilot of the most most principal helicopter despatched to get well Grissom and Liberty Bell 7.

In accordance to the accessible evidence, we cessation that electrostatic discharge generated at some level of the in the kill unsuccessful attempt to get well Grissom’s spacecraft most likely precipitated the premature detonation of the explosive hatch.

Here’s what we deem transpired in the exiguous more than 11 minutes between splashdown and hatch detonation:

After landing in the Atlantic Ocean roughly 300 miles (480 kilometers) east of Cape Canaveral, Florida, Grissom evenly proceeded down his pointers. He undid his harnesses, disconnected his biomedical sensors, and, in step with the contemporary recovery course of, rolled up a neck dam to seal his stress suit in anticipation of coming into the water.

Grissom’s neck dam is clearly considered on this post flight photos from the recovery ship, USS Randolph, as he takes a congratulatory name from President Kennedy. (Credit: NASA/Andy Saunders. Offer: Stephen Slater)

Overjoyed that he became in correct situation after splashdown, and, in step with air-to-ground communications, exhibiting no indicators of hurt, vital less effort, Grissom decided to arm the hatch. First, he eradicated the hatch restraining wires and a custom survival knife that became hooked up to the door, inserting the latter in his survival pack. He then eradicated a quilt and safety pin to arm the mechanically operated hatch detonator, whose plunger required about 5 pounds (2.3 kilograms) of force to be caused after the safety pin became eradicated.

He then ready for the arrival of recovery helicopters by deploying recovery aids, in conjunction with a dye marker and a 22-foot-prolonged (6.7 meters) excessive-frequency whip antenna for speaking with the most most principal recovery helicopter, Hunt Club 1. Once the hatch sill became hoisted above the water line, the knowing became for Grissom to blow the hatch and lift a ready horse collar.

Grissom awaits recovery — the 22-foot whip antenna is clearly considered on this stacked, processed image. (Credit: NASA/Andy Saunders. Offer: Stephen Slater)

Hunt Club 1 became piloted by Lewis. Crewman Reinhard became stationed at a aspect door and ready to lower the whip antenna in step with a up to date course of. Reducing the prolonged antenna would allow Lewis to plug in unobstructed, so Reinhard would possibly even then hook onto the spacecraft after Grissom detonated the hatch.

A raw soundless frame from the recovery photos exhibiting Hunt Club 1 coming advance Liberty Bell 7. (Credit: NASA/Andy Saunders. Offer: Stephen Slater)

Reinhard’s diagram for the job, usually known as a cookie cutter, became a jury-rigged affair — in fact a tree-­pruning pole geared up with cutters actuated by pyrotechnics that were accepted with the inspire of engineers at what is now the U.S. Navy’s red meat up facility at Dahlgren, Virginia. (A search of Dahlgren’s archives for principal aspects of the diagram came up empty). The invent enabled Reinhard to reach out of the aspect door of Hunt Club 1 with the prolonged pole and lop the antenna, which would possibly even otherwise interfere with the recovery helicopter.

Reinhard, who died in July 2020, steered researcher Rick Boos in the unhurried 1990s that when he reached down to snip the antenna, he seen an electrostatic arc. “Gus acknowledged that he became ready and we slid over,” Reinhard steered Boos. “After I touched the antenna, there became an arc.” Reinhard explained that the cookie cutter integrated two blades with two explosive squibs. On the identical time he seen the electrostatic discharge, he recalled, “each [squibs] had long past off with out my activating them, and they were on two separate switches!” Pressed by Boos to clarify his commentary, Reinhard became unequivocal: “After I touched the antenna there became an arc, and each cutters fired. On the identical time, the hatch came off. It’ll be that some static price living [the hatch] off.”

Whereas Reinhard didn’t thought the hatch in fact blow, he did leer the hatch skipping several toes from the spacecraft, followed seconds later by Grissom, who managed to wedge his manner out of the slender hatch opening. The 5-foot 7-high-tail (1.7m) astronaut had eradicated his helmet as water poured into his spacecraft, grabbed the supreme aspect of his cockpit cowl panel, and deserted ship. He later acknowledged he had “by no come moved sooner.”

Hunt Club 1 became no longer grounded, as would later become a requirement under U.S Navy and Cruise Guard pointers for sea rescues. Notably, Reinhard became no longer basically the most attention-grabbing one to experience most principal static discharge at some level of this kind of course of. Peter Armitage, who helped develop Mission Mercury recovery procedures in conjunction with the cookie cutter, noteworthy in a NASA oral ancient past interview that his un-gloved hands got a jolt at some level of a take a look at bustle when he touched a boilerplate Mercury spacecraft, vital to the amusement of the Marines fresh. This ability such discharges were a standard, anticipated incidence. Hence, Reinhard’s recollection of static discharge at this 2nd is no longer in quiz.

To corroborate Reinhard’s recollections, we have enhanced and analyzed the unusual recovery movie photos. The HD transfer became enlarged, enhanced, stabilized, and inspected for any circulation terminate to the capsule as Hunt Club 1 approaches, which would possibly even cowl the hatch blowing out. The most efficient circulation seen on this entire sequence appears to be like in 17 consecutive frames (covering 0.7 seconds) and moves upward and away from the listing spacecraft (these are no longer movie artifacts, as artifacts would most efficient appear on occasional, random frames).

The enhanced, stabilized photos (performed alternately forward then backward) also has movie artifacts eradicated. It presentations circulation from the positioning of the hatch — ascertained from a later frame exhibiting Grissom’s egress. (Offer photos: NASA/Stephen Slater. Reprocessing: Andy Saunder)


Unruffled frames from the enhanced video. Left: a frame initially of the sequence. Trustworthy: one amongst the next frames exhibiting that you would possibly possibly take into accounts hatch and ocean spray. (Credit: NASA/Andy Saunders. Offer: Stephen Slater)

Regardless of noteworthy enhancement, it is no longer doable to positively resolve that right here is the hatch. It does appear to personal a runt, ranking murky living amongst a more frequent murky living. This is indicative of the hatch blowing out amongst spray from the ocean, because the brink of the hatch would contain been below the water line because Liberty Bell 7 became listing at this level in the photos. This corroborates Grissom’s later commentary: “I heard the hatch blow … looked up to ogle blue sky … and water birth to spill over the doorsill.” It is miles also telling that this circulation, which would possibly no longer be a movie artifact, starts at the remark space of the hatch, as confirmed by superimposing a later frame exhibiting Grissom’s egress, and moves in an upward and outward course.

The placement of the hatch will also be obvious as Grissom exits the capsule in these later, stacked and enhanced frames. The snipped antenna is clearly considered. (Credit: NASA/Andy Saunders. Offer: Stephen Slater)

If right here is the hatch, then what is going down with Hunt Club 1 at this real 2nd? Single frames cowl exiguous, in particular for the reason that events were shot on runt-structure movie from gigantic distance and into the Solar. The enhanced movie, nevertheless, unearths the shadows in the silhouetted aspect of Hunt Club 1. We achieved this by stacking the 17 frames that encompass the irregular circulation, along with an additional few frames on both aspect to quilt approximately 1 2nd of elapsed time. This stacking course of vastly enhances detail and remarkably, for the most most principal time, unearths Reinhard standing in the doorway of the recovery helicopter with a pole outstretched toward the capsule.

A single, enhanced frame unearths exiguous of the silhouetted aspect of Hunt Club 1. Trustworthy: 26 stacked, enhanced frames of the movie cowl Reinhard in the doorway with a pole outstretched toward the capsule. (Credit: NASA/Andy Saunders. Offer: Stephen Slater)

A straight line following the course of the considered share of the pole became superimposed past where it becomes less considered. The highway intersects the precise space above the capsule where the antenna became lower:

Left: A straight line drawn from Reinhard’s correct hand along the highway of the pole, intersects an living above Liberty Bell 7 where the antenna became lower (confirmed inset). Trustworthy: A later frame in the sequence presentations the scale of the separate “shepherd’s hook” pole. (Credit: NASA/Andy Saunders. Offer: Stephen Slater)

Along with the cookie cutter talked about above, Reinhard’s different diagram became a pole often usually known as a “shepherd’s hook,” which would possibly be accepted to snag the recovery ring on Liberty Bell 7. Scaling a later frame that presentations the scale of the separate shepherd’s hook pole confirms that, if each poles are of an analogous dimension, Reinhard would possibly even undoubtedly contain reached the antenna at this 2nd.

Our conclusion from the contemporary image enhancement and evaluation is that Reinhard became nearly undoubtedly cutting the antenna at the remark 2nd that upward and outward circulation is seen from the positioning of the hatch in 17 consecutive enhanced frames. Grissom is considered exiting the spacecraft 5.2 seconds later.

We deem the recovery operations generated a static shock because the cutter contacted the antenna. The timeline of events, seen in the newly enhanced photos, also appears to be like to verify Reinhard’s version of events.

The electrostatic discharge became enough to inadvertently activate the pyrotechnic devices on the cutter. But would possibly even it even contain activated the explosive hatch?

The hatch became secured to the doorsill by seventy (70) ¼­-high-tail-diameter (3.6 cm) titanium bolts with 0.06-high-tail (0.2 cm) holes drilled into each dart to present a former level. A serene detonating fuse became installed in the channel between the inner and outer hatch seals. When ignited, the explosion precipitated the weakened bolts to fail, blowing the hatch.

The topic matter details sheet for mercury fulminate highlights its sensitivity to static electricity.

In accordance to salvage expert Curt Newport, who recovered Liberty Bell 7 in 1999, the detonator percussion caps that served as a triggering mechanism seemingly contained mercury fulminate. Industry specs supplied to us by Newport warn that the inherently unstable compound “can detonate” in the presence of static electricity. Extra, a NASA handbook on the invent and qualification of spacecraft pyrotechnics makes several references to static electricity as a safety scenario. The handbook also urges designers to “quit inadvertent initiation” of spacecraft pyrotechnics by “electrostatic discharge.”

Utterly different Mercury spacecraft parts were topic to rigorous reliability testing in efforts to enact “five nines,” or 99.999 percent reliability. Robert Voas, who assisted with early astronaut practising, steered us the exploding hatch became a “Johnny-come-no longer too prolonged ago thing that had by no come been examined by any other flight.” Voas continued: “My witness of this incident is that it became produced by the barely final­ minute alternate in going to an explosive door … you would possibly possibly like to, indubitably, engineer the door. It be principal to hold in thoughts every merchandise on that spacecraft became topic to the reliability program.”

Grissom made one mistake: arming the hatch earlier than the hatch sill became safely above the water line. This seemingly mirrored his unfamiliarity with the hatch mechanism and inadequate recovery practising. The one and possibly most efficient identified field take a look at of the exploding hatch befell on July 10, 1961, with astronaut Grissom staring at. The take a look at became performed exiguous more than every week earlier than Grissom’s scheduled originate date, extra indicating what Voas concluded became a rushed constructing and testing program for the contemporary hatch, as nicely as inadequate practising in recovery procedures.

It is telling that the Liberty Bell 7 recovery procedures were by no come all once more accepted. Restoration steps for later Mercury flights explicitly stipulated that the detonator would possibly even soundless no longer be armed unless a recovery helicopter bent on and lifted the hatch sill above the water line.

Fellow astronauts took to coronary heart the exhausting lesson of Grissom’s terminate to drowning, as he struggled to pause afloat amid Hunt Club 1’s in fact intensive prop wash. (Grissom had rolled up his neck dam to take care of seawater from seeping into his stress suit, however forgot — or by no come had a bet — to terminate an oxygen inlet on his suit, which precipitated him to immediate lose buoyancy in the ocean swells.)

On all later Mercury flights other than one, the astronauts take care of to blow the hatch whereas on the deck of the recovery ship. Wally Schirra sustained a lower to his gloved hand from the plunger recoil, an hurt Grissom didn’t contain. Via the years, Schirra time and all once more pointed to this reality as proof that Grissom didn’t touch, deliberately or unintentionally, the hatch detonator (or, as living veterans known because it, the “rooster swap”).

The advice that Grissom worried at the cessation of his flight is patently absurd. Why, after flying a ballistic trajectory atop a Redstone rocket, experiencing weightlessness for five minutes, pulling as many as 10 Gs at some level of re-entry, staring at a triangular rip in his most most principal recovery parachute — why would Grissom effort? If anything else, bobbing in the heat Atlantic, 60 years ago this week, the astronaut completely would contain been relieved to contain survived his flight. Grissom will also be considered in the recovery photos swimming toward his spacecraft, guiding the recovery personnel to hook the recovery line, even giving the double thumbs up whereas treading water.

Grissom presents the thumbs-up to Hunt Club 1 on this stacked, enhanced image at some level of recovery operations. The dye from the dye marker canister is also considered in the encompassing waters.
(Credit: NASA/Andy Saunders. Offer: Stephen Slater)

We confirmed our results to Hunt Club 1 pilot Jim Lewis, who since the day of Grissom’s flight had recalled a determined situation. His response?

“My accepted impact of events became that the hatch blew as I became finishing our come to Liberty Bell 7, however Andy Saunders’s awesome work on the recovery movie has in fact made me re-witness my memory banks,” Lewis acknowledged in an email alternate. “In accordance to this work, Reinhard need to contain lower the antenna a mere 2nd or two earlier than I got us ready for him to connect our harness to the capsule lifting bale. It would appear that the hatch would possibly even nicely contain blown at this 2nd, something that this intensive background study appears to be like to corroborate.”

It is acknowledged that static electricity follows the direction of least resistance. If that’s the case, we posit that an electron ­stuffed vortex generated by helicopter prop wash seemingly generated an arc that detonated the unqualified exploding hatch that became with out warning examined and installed on Liberty Bell 7.

As the recovery photos becomes clearer, so too contain the waters, which contain been muddied for six decades by rumour and speculation over one amongst NASA’s most enduring mysteries. Gus Grissom, in the placement we fresh right here on the 60th anniversary of his flight, can at final be fully exonerated from blame for upfront blowing the hatch of Liberty Bell 7.


The authors resolve to acknowledge the tireless study from Rick Boos (who died this year because of considerations from COVID-19).

George Leopold (Twitter: @gleopold1) is the creator of Calculated Threat: The Supersonic Life and Cases of Gus Grissom.

Andy Saunders (Twitter: @AndySaunders_1 and Instagram: andysaunders_1) is an imaging specialist and creator of the upcoming e-book Apollo Remastered, now accessible for pre-repeat, right here. That you just would be able to signal in for additonal updates on the e-book at ApolloRemastered.com.

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