Sunday, March 21, 2021

MRBD- The flight Shepard and Craft hated

The following is an excerpt from the book "Growing up with Spaceflight- PROJECT MERCURY" and is protected by Copyright 2015 Wes Oleszewski, no part may reproduced without expressed permission or the author.


When asked what kind of fuels it took to get the United States to the Moon, few average folks can give the correct answer. Those who are space-buffs or who actually are a part of the aerospace industry can usually name off the propellants such as LOX, RP1, LH2 and assorted hypergolic fuels. Although they are correct, they often leave out one critical fuel without which no human would ever have set foot on the lunar surface. The “fuel” that was required in the greatest quantity was... political fuel.

On March 24, 1961, an event took place that, through completely unintended consequences, would open wide the political fuel valves. It was the flight monikered as “MR-BD.” Completely unknown to those outside the program, yet destined to significantly affect the space history books, this single launch caused a good deal of animosity inside Project Mercury. Thus, it became an event that is often overlooked, and deliberately shunned by NASA itself because MR-BD caused the dominos of history to fall away from the favor of the United States and into the direction of the Soviet Union. People working on Project Mercury soon saw its effect as causing their immediate embarrassment in the press and in the eyes of the public. The result of the MR-BD colored the USA as being in "second place" in the “space race.”

Because the MR-BD mission was injected into the flight schedule, Alan Shepard’s flight was pushed back nearly two months. That allowed the Soviets to place Yuri Gagarin into orbit two weeks ahead of Shepard’s flight, and, in the eyes of the world, “win” the glory of having put the first man into space. To many at NASA, the MR-BD was seen as an unnecessary schedule slip that cost them the prize of being first. 

 With the hindsight of a historian, however, MR-BD can be viewed very differently.

MR-BD was an acronym that stood for “Mercury Redstone – Booster Development." It was an extra flight that famed German rocket scientist Wernher von Braun and his team insisted must be placed into the schedule of the Mercury Redstone test flight series leading toward Alan Shepard’s suborbital mission. In the original schedule, Shepard’s MR-3 mission was supposed to launch during the third week of March. If the Soviets did not pull a red rabbit out of their hat Shepard would become the first man in space and thus “win” the space race for the United States. The problem was that all three of the previous unmanned Mercury Redstone launch attempts had run into a series of small problems with serious and, in two cases, embarrassing consequences.

When the first Mercury Redstone, MR-1, attempted to launch it had a mismatch in a two-pronged plug that pulled out of the base of the booster at the instant of liftoff. That plug was designed so that when it pulled out, as the booster began to lift from the launch ring, one prong, being one-half-inch shorter than the other, would disconnect first. On all previous Redstone's that had not been a problem because none of them had been wired the same as the manned version. In this case, the two prongs disconnected 20 milliseconds apart. Although that time span seems extremely brief to a human, in the area of electronics where electrons flow at the speed of light, 20 milliseconds is a very long time. The Mercury Redstone’s automatic system sensed the difference and shut the engine down. With that, the booster simply set back down onto the launch ring. But the electronic brain was still working and it saw this as a normal shutdown, as if the vehicle was in flight, so it automatically jettisoned the escape tower! With the escape tower gone and no acceleration being sensed, the capsule’s programming told it to go into recovery mode and it then deployed the main and reserve parachutes which popped out like corks. To say that this was embarrassing would be something of an understatement.

MR-1A was the next attempt and although it appeared to fly normally, later data analysis would show a critical problem. The carbon vanes that jutted into the exhaust flame to steer the Redstone showed an unexpected vibration. The frequency and the magnitude of that vibration grew very near to the predicted lifespan of the servo motors which moved the vanes. Loss of one of them could have easily resulted in the loss of vehicle control. It was determined that the vibration was caused simply by “…the lowered second bending frequency of the Mercury-Redstone booster-capsule configuration.”

MR-2 was next and would carry Ham the chimp. At first the flight looked normal, but for reasons that were unapparent at the time, the booster was ascending too steeply and depleting its fuel at a higher than normal rate. This was caused by the thrust controller’s servo control valve being stuck in the full open position. The result was that the propellant fully depleted at exactly 137 seconds into the burn. That was 5.5 seconds before schedule and .5 seconds prior to where the integrating accelerometer was set to arm. The Abort Sensing Implementation System (ASIS) sensed the anomaly and commanded an abort, firing the escape tower and pulling the Mercury spacecraft and Ham the chimp away from the booster. Instead of an expected maximum 12 G acceleration, Ham got hit with abort-level acceleration. He splashed down 137 miles farther downrange than planned and took about 17 G’s in the process.

Although NASA officials later displayed a healthy Ham as proof of a successful flight, the fact was that this had been an abort, pure and simple. The flight was actually aborted during boosted flight by the triggering of the ASIS. The fact that the chimp had survived was actually immaterial. Had Shepard or any other of the seven Mercury astronauts been onboard that flight, the Soviets, as well as American critics of the program (some of the most vocal of whom were actually advising President Kennedy), would have been quick to point out that all NASA had done was boost the capsule to the point where the mission was aborted by the automatic system designed to save the astronaut’s life.

In the wake of the growing laundry list of little failures, the von Braun team decided that another unmanned flight was required to test the fixes for the problems. Members of the Space Task Group, which if you will recall were the engineers charged with building the foundation of NASA’s manned space efforts, chose to ignore the von Braun team’s list of launch vehicle issues. The STG deemed the problems to be minor. Thus, the STG recommended to NASA headquarters that Shepard’s MR-3 mission should “go” according to its original schedule and launch in March. Even decades later, former members of the STG hold to their original position. In his autobiography "Flight" former Mercury flight director Chris Kraft states

“The Germans were embarrassed by the Redstone’s performance on MR-2, and by their failure to predict its fuel flow.”

Of course he ignores the fact that a stuck servo control valve nullified any fuel flow predictions made by “…the Germans…” or anyone else. One thing he does get right, however, is his statement that the STG gang was “furious” when von Braun insisted on another test.  Shepard himself recalled in his autobiography "Moon Shot" that the problem was a simple relay and nothing more, which is also far from being factual.

In fact, in their March 20, 1961, memorandum addressing the problems with the first three Mercury Redstone flights, the STG itself cited a total of nine different issues as presented by the von Braun team at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama. They were: 1) Rudder and carbon vane vibration, 2) Instrument compartment vibration, 3) Thrust controller, 4) H202 tank pressure regulator, 5) Cutoff arming timer, 6) Roll abort sensor, 7) H202 system controller, 8) Man-hole LOX leak, and 9) Velocity integrator. It is easy to see that the issue was a chain of malfunctions that caused the flight of MR-BD to be placed into the schedule. NASA Headquarters agreed. MR-BD would fly in late March of 1961.

So put off was the STG over this decision that they refused to allow the von Braun team to designate the flight as MR-2A or MR-3 and, again according to Kraft’s book, they forced “the Germans” to use MR-BD as the moniker. They also refused to allocate an actual flight version of the Mercury capsule and denied the use of a live escape tower. Instead the MR-BD was topped with a used boiler-plate Mercury capsule from the Little Joe 1B mission and an inert escape tower. Nearly a half century later, Kraft still referrers to the MR-BD as being “…von Braun’s unnecessary Redstone test.”

In aviation, or aerospace, the way that you prevent an accident or a catastrophe is when you see a chain of circumstances or failures that may lead to the accident; you break the chain. You recognize the related issues as they add up and correct the problems. In the case of MR-BD that is what the folks at MSFC did. The flight of MR-BD went off smoothly as every one of the fixes made by the von Braun team worked. Now the stage was set for the first manned Mercury Redstone flight.

By delaying the schedule, the MR-BD inadvertently played directly into the hands of the Soviets. On April 12, 1961, they launched Gagarin’s Vostok spacecraft and claimed the title of having put the first man into space. They had the illusion that this milestone would be a morale-buster for the United States and those people in the West. The Soviets, however, were badly mistaken. 

There is nothing Americans hate more than losing, and coming in second is considered as just being the first one to lose. America’s new president, John F. Kennedy, had campaigned on the notion that the United States was falling behind the Soviets in many areas, especially spaceflight. It was an easy point to make considering the indifferent posture the Eisenhower administration took toward manned spaceflight. Yet, the shockwave that went through the American public due to the Vostok mission’s success now gave Kennedy the perfect opportunity to fulfill his campaign rhetoric.

Across the United States the idea that “the Russians are beating us” became entrenched among the public at large. In Congress, members heard from their home districts as the “What are you going to do about it?” questions came from every corner. Kennedy now had the political fuel needed, not only to set the course of the United States toward the Moon, but also to gain the public inertia required to actually accomplish that goal over time.

Had the STG, Chris Kraft, Alan Shepard,, gotten their way and had Shepard flown before Gagarin, Americans would likely have thrown up their collective hands and said “We Won! The space race is over!” And it may very well have been the end as the political fuel to go beyond Project Mercury would have quickly evaporated.


Thus, MR-BD, just by happenstance, was a very key link in the chain of events that led to United States astronauts actually getting to the Moon. It served to open the valve that allowed the political fuel to flow, and Vostok provided the spark that ignited Kennedy and propelled a nation. Although often missed as an easily overlooked footnote, the unintended consequences of that single mission would ensure that toddlers like me, and perhaps you, would have a space program to grow up with. 

The Growing up with Spaceflight books can be found at Amazon
Or at, where you can get them autographed and personalized.

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