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HAM in a Can

Fifty-four years ago this month, NASA successfully conducted a critical flight test of the space agency’s Mercury-Redstone launch vehicle which helped clear the way for the United States’ first manned suborbital spaceflight. Riding the diminutive Mercury spacecraft into space and back was a 44-month old male chimpanzee by the name of HAM.

Project Mercury was America’s first manned spaceflight program. Simply put, Mercury helped us learn how to fly astronauts in space and return them safely to earth. A total of six (6) manned missions were flown between May of 1961 and May of 1963. The first two (2) flights were suborbital shots while the final four (4) flights were full orbital missions. All were successful.

The Mercury spacecraft weighed about 3,000 lbs, measured 9.5-ft in length and had a base diameter of 6.5-ft. Though diminutive, the vehicle contained all the systems required for manned spaceflight. Primary systems included guidance, navigation and control, environmental control, communications, launch abort, retro package, heatshield, and recovery.

Mercury spacecraft launch vehicles included the Redstone and Atlas missiles. Both were originally developed as weapon systems and therefore had to be man-rated for the Mercury application. Redstone, an Intermediate Range Ballistic Missile (IRBM), was the booster for Mercury suborbital flights. Atlas, an Intercontinental Ballistic Missile (ICBM), was used for orbital missions.

Early Mercury-Redstone (MR) flight tests did not go particularly well. The subject missions, MR-1 and MR-1A, were engineering test and development flight tests flown with the intent of man-rating both the converted launch vehicle and new manned spacecraft.

MR-1 hardly flew at all in that its rocket motor shut down just after lift-off. After soaring to the lofty altitude of 4-inches, the vehicle miraculously settled back on the launch pad without toppling over and detonating its full load of propellants. MR-1A flew, but owing to higher-than-predicted acceleration, went much higher and farther than planned. Nonetheless, MR flight testing continued in earnest.

The objectives of MR-2 were to verify (1) that the fixes made to correct MR-1 and MR-1A deficiencies indeed worked and (2) proper operation of a bevy of untested systems as well. These systems included environmental control, attitude stabilization, retro-propulsion, voice communications, closed-loop abort sensing and landing shock attenuation. Moreover, MR-2 would carry a live biological payload (LBP).

A 44-month old male chimpanzee was selected as the LBP. He was named HAM in honor of the Holloman Aerospace Medical Center where the primate trained. HAM was taught to pull several levers in response to external stimuli. He received a banana pellet as a reward for responding properly and a mild electric shock as punishment for incorrect responses. HAM wore a light-weight flight suit and was enclosed within a special biopack during spaceflight.

On Tuesday, 31 January 1961, MR-2 lifted-off from Cape Canaveral’s LC-5 at 16:55 UTC. Within one minute of flight, it became obvious to Mission Control that the Redstone was again over-accelerating. Thus, HAM was going to see higher-than-planned loads at burnout and during reentry. Additionally, his trajectory would take him higher and farther downrange than planned. Nevertheless, HAM kept working at his lever-pulling tasks.

The Redstone burnout velocity was 5,867 mph rather than the expected 4,400 mph. This resulted in an apogee of 137 nm (100 nm planned) and a range of 367 nm (252 nm predicted). HAM endured 14.7 g’s during entry; well above the 12 g’s planned. Total flight duration was 16.5 minutes; several minutes longer than planned.

Chillingly, HAM’s Mercury spacecraft experienced a precipitous drop in cabin pressure from 5.5 psig to 1 psig just after burnout. High flight vibrations had caused the air inlet snorkel valve to open and dump cabin pressure. HAM was both unaware of and unaffected by this anomaly since he was busy pulling levers within the safety of his biopack.

HAM’s Mercury spacecraft splashed-down at 17:12 UTC about 52 nm from the nearest recovery ship. Within 30 minutes, a P2V search aircraft had spotted HAM’s spacecraft (now spaceboat) floating in an upright position. However, by the time rescue helicopters arrived, the Mercury spacecraft was found floating on its side and taking on sea water.

Apparently, a combination of impact damage to the spacecraft’s pressure bulkhead and the open air inlet snorkel valve resulted in HAM’s spacecraft taking on roughly 800 lbs of sea water. Further, heavy ocean wave action had really hammered HAM and the Mercury spacecraft. The latter having had its beryllium heatshield torn away and lost in the process.

Fortunately, one of the Navy rescue helicopters was able to retrieve the waterlogged spacecraft and deposit it safely on the deck of the USS Donner. In short order, HAM was extracted from the Mercury spacecraft. Despite the high stress of the day’s spaceflight and recovery, HAM looked pretty good. For his efforts, HAM received an apple and an orange-half.

While the MR-2 was judged to be a success, one more flight would eventually be flown to verify that the Redstone’s over-acceleration problem was fixed. That flight, MR-BD (Mercury-Redstone Booster Development) took place on Friday, 24 March 1961. Forty-two (42) days later USN Commander Alan Bartlett Shepard, Jr. became America’s first astronaut.

MR-2 was HAM’s first and only spaceflight experience. He quietly lived the next 17 years as a resident of the National Zoo in Washington, DC. His last 2 years were spent living at a North Carolina zoo. On Monday, 19 January 1983, HAM passed away at the age of 26. HAM is interred at the New Mexico Museum of Space History in Alamogordo, NM.

Posted in Aerospace, History

Navaho Flight Test Milestone

Fifty-seven years ago this month, a XSM-64 Navaho G-26 flight test vehicle flew 1,075 miles in 40 minutes at a sustained speed of Mach 2.8. It was the 8th flight test of the ill-fated Navaho Program.

The post-World War II era saw the development of a myriad of missile weapons systems. Perhaps the most influential and enigmatic of these systems was the Navaho missile.

Navaho was intended as a supersonic, nuclear-capable, strategic weapon system. It consisted of two (2) stages. The first stage was rocket-powered while the second stage utilized ramjet propulsion. The aircraft-like second stage was configured with a high lift-to-drag airframe in order to achieve strategic reach.

While there were a number of antecedents dating back to 1946, the Navaho Program really began in 1950 as Weapon System 104A. The requirements included a range of 5,500 miles, a minimum cruise speed of Mach 3 and a minimum cruise altitude of 60,000 feet. The payload included an ordnance load of 7,000 pounds delivered within a CEP of 1,500 feet.

North American Aviation (NAA) proposed a 3-phase development plan for WS-104A. Phase 1 involved testing of the missile alone (the X-10) up to Mach 2. Phase 2 covered the testing of the two-stage launch vehicle (the G-26) up to Mach 2.75 and a range of 1,500 miles. Phase 3 would be the ultimate near-production vehicle (the G-38). Only Phase 1 and Phase 2 testing took place.

The Navaho missile-booster vehicle measured 84 feet in length and weighed about 135,000 pounds at lift-off. The launch weight for the booster was 75,000 pounds; most of which was due to the alcohol and LOX propellants. The missile empty weight was 24,000 pounds.

On Friday, 10 January 1958, Navaho G-26 No. 9 (54-3098) lifted-off from LC-9 at Cape Canaveral, Florida. Climbing out under 240,000 pounds of thrust from its dual Rocketdyne XLR71-NA-1 rocket motors, missile-booster separation occurred at Mach 3.15 and 73,000 feet. Following air-start and take-over of twin Wright XRJ47-W-5 ramjets, generating a combined thrust of 16,000 pounds, the Navaho missile initiated a near triple-sonic cruise toward the Puerto Rico target area.

As the Navaho missile approached the environs of Puerto Rico, the vehicle was commanded to initiate a sweeping right-hand turn back towards the Cape. Unfortunately, the right intake experienced an unstart and a concomitant, asymmetric loss of thrust. Underpowered and without a restart capability, the vehicle was subsequently commanded to execute a dive into the Atlantic.

Flight No. 8, although only partially successful, flew longer and farther than any Navaho flight test vehicle. Only G-26 Flight No. 6 flew faster (Mach 3.5).

Although three (3) flights would follow G-26 Flight No. 8, all would suffer failure of one kind or another. In point of fact, the Navaho Program had been canceled on Saturday, 13 July 1957. The final six (6) Navaho flights were simply an attempt to extract the most from the remaining missile-booster rounds. Over 15,000 NAA employees lost their jobs the day Navaho died.

Navaho was cancelled primarily due to the ascendancy of the Intercontinental Ballistic Missile (ICBM). Very simply, an ICBM could deliver nuclear ordnance farther, faster and more accurately than a winged, unstealthy strategic missile. Navaho’s relatively numerous technical issues and programmatic delays simply served to drive the final nail into a long-prepared coffin.

While few today remember or even know of the Navaho Program, its technology has had a profound influence on all manner of aerospace vehicles up to the present day. Interestingly, the Space Shuttle launch vehicle concept bears a strong resemblance to the Navaho missile-booster combination. That is, a winged flight vehicle mounted asymmetrically on a longer boost vehicle.

Posted in Aerospace, History

Final Flight: Cactus 1549

Six years ago this month, US Airways Flight 1549 successfully ditched in the Hudson River following loss of thrust in both turbofan engines. Incredibly, all 155 passengers and crew members survived.

US Airways Flight 1549 lifted-off from Runway 4 of New York’s LaGuardia Airport at 18:25:56 UTC on Thursday, 15 January 2009. The Airbus 320-214 (N106US) was making its 16,299th flight. Call sign for the day’s flight was Cactus 1549.

Captain Chesley B. Sullenberger III and First Officer Jeffrey B. Skiles were in the cockpit of Cactus 1549. Donna Dent, Doreen Welsh and Sheila Dail served as flight attendants. Together, these crew members were responsible for the lives of 150 airline passengers.

Following a normal take-off, Cactus 1549 collided with a massive flock of Canadian Geese climbing through 3,000 feet. Numerous bird strikes were experienced. Most critically, both CFM56-5B4/P turbofan engines suffered bird ingestion. As Captain Sullenberger suscinctly described it later, the result was “sudden, complete, symmetrical” loss of thrust.

Quickly assessing their predicament, Captain Sullenberger instinctively knew that he could not get his aircraft back to a land-based runway. He was flying too low and slow to make such an attempt. He would have to ditch his 150,000-pound aircraft in the nearest waterway; the Hudson River.

The story of what ensued following loss of thrust is best told by Captain Sullenberger himself. The reader is therefore directed to chapters 13 and 14 of his post-mishap book entitled “Highest Duty”. The bottom line is that the aircraft was successfully ditched in the Hudson River roughly three and half minutes after loss of thrust in both engines.

Once the aircraft was on the water, the crew members evacuated all 150 passengers in less than 4 minutes. People either got into life rafts or stood on the aircraft’s wings. It was very cold. Air temperature was 21F with a windchill factor of 11F. The water temperature registered at 36F.

First responders from the New York Waterway quickly came to the aid of Cactus 1549. A total of fourteen vessels responded to the emergency with the first boat arriving within four minutes of the aircraft coming to a stop.

Many selfless acts of compassion and exemplary displays of valor were observed during Cactus 1549 rescue operations. This was true for those amongst the ranks of the rescuers and rescued alike.

Happily and to the great relief of the US Airways flight crew, there was no loss of life resulting from the emergency ditching of Cactus 1549. Now known as “The Miracle on the Hudson”, the events of that harrowing experience on a winter day in NYC will be forever remembered in the annals of aviation.

For their professional efforts in handling the Cactus 1549 in-flight emergency, Chesley Sullenberger, Jeff Skiles, Donna Dent, Doreen Welsh and Sheila Dail received the rarely-awarded Guild of Air Pilots and Air Navigators Master’s Medal on Thursday, 22 January 2009.

In part, the Master’s Medal citation read: “The reactions of all members of the crew, the split second decision making and the handling of this emergency and evacuation was ‘text book’ and an example to us all. To have safely executed this emergency ditching and evacuation, with the loss of no lives, is a heroic and unique aviation achievement.”

To which we say: Amen!

Posted in Aerospace, Final Flight, History