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Narrow Escape

Fifty-one years ago this month, NASA Astronaut Neil A. Armstrong narrowly escaped with his life when he was forced to eject from the Lunar Landing Research Vehicle in which he was training. Armstrong punched-out only 200 feet above ground level and spent just 4 seconds in the silk before safely landing.

The Lunar Module (LM) was the vehicle used by Apollo astronauts to land on and depart from the lunar surface. This unique spacecraft consisted of separate descent and ascent rocket-powered stages. The powered descent phase was initiated at 50,000 feet AGL and continued all the way to landing. The powered ascent phase lasted from lunar lift-off to 60,000 feet AGL.

It was recognized early in the Apollo Program that landing a spacecraft on the lunar surface under vacuum conditions would be very challenging to say the least. To maximize their chances for doing so safely, Apollo astronauts would need piloting practice prior to a lunar landing mission. And they would need an earth-bound vehicle that flew like the LM to get that practice.

The Lunar Landing Research Vehicle (LLRV) was the answer to the above. The LLRV employed a turbojet engine that provided vertical thrust to cancel five-sixths of its weight since the gravity on the Moon is one-sixth that of Earth. The vehicle was also configured with dual lift rockets to provide vertical and horizontal motion. LLRV 3-axis attitude control was provided by a series of 16 small thrusters.

The LLRV was described by one historical NASA document as being “unconventional, contrary and ugly”. Known as the “Flying Bedstead”, the LLRV was designed for the specific purpose of simulating LM flight during the terminal phase of a lunar landing. The LLRV was not easy to fly in the “low and slow” flight regime in which it operated. The type was aesthetically unattractive in the extreme.

A pair of LLRV’s were constructed by Bell Aerosystems and flight tested at what is now the NASA Dryden Flight Research Center starting in October 1964. These vehicles were subsequently shipped to Ellington Air Force Base in Texas by early 1967. A number of flight crew, including Neil Armstrong, began LLRV flight training shortly thereafter.

Neil Armstrong made his first LLRV flight on Monday, 27 March 1967 in LLRV No. 1. (This occurred two months after the horrific Apollo 1 Fire.) Armstrong continued flight training in the LLRV over the next year in preparation for what would ultimately be the first manned lunar landing attempt in July of 1969

On Monday, 06 May 1968, Armstrong was flying LLRV No. 1 when the vehicle began losing altitude as its lift rockets lost thrust. Using turbojet power, Armstrong was able to get the LLRV to climb. As he did so, the vehicle made an uncommanded pitch-up and roll over. The attitude control system was unresponsive. The pilot had no choice but to eject.

Neil Armstrong ejected from the LLRV at 200 feet AGL as LLRV No. 1 crashed to destruction. The pilot was subjected to an acceleration of 14 G’s as his rocket-powered, vertically-seeking ejection seat functioned as designed. Armstrong got a full chute, but made only a few swings in same before safely touching-down back on terra firma. His only injury was to his tongue, which he accidently bit at the moment of ejection seat rocket motor ignition.

A mishap investigation board attributed the LLRV mishap to a design deficiency that allowed the helium gas pressurant of the lift rocket and attitude control system fuel tanks to be be accidently depleted. Thus, propellants could not be delivered to the lift rockets and attitude control system thrusters.

Neil Armstrong and indeed all of the Apollo astronauts who landed on the Moon trained in improved variants of the LLRV known as the Lunar Landing Training Vehicle (LLTV). This training was absolutely crucial to the success of the half-dozen Apollo crews who landed on the Moon. Indeed, there was no other way to adequately simulate moon landings except by flying the LLTV.

Posted in Aerospace, History

Skylab Rescue

Forty-six years ago this month, astronauts Pete Conrad, Joe Kerwin and Paul Weitz became the first NASA crew to fly aboard the recently-orbited Skylab space station. Not only would the crew establish a new record for time in orbit, they would effect critical repairs to America’s first space station which had been seriously damaged during launch.

Skylab was America’s first space station. The program followed closely on the heels of the historic Apollo lunar landing effort. Skylab provided the United States with a unique space platform for obtaining vast quantities of scientific data about the Earth and the Sun. It also served as a means for ascertaining the effects of long-duration spaceflight on human beings.

A Saturn IVB third stage served as Skylab’s core. This huge cylinder, which measured 48-feet in length and 22-feet diameter, was modified for human occupancy and was known as the Orbital Workshop (OWS). With the addition of a Multiple Docking Adapter (MDA) and Airlock Module (AM), Skylab had a total length of 83-feet.

Skylab was also outfitted with a powerful space observatory known as the Apollo Telescope Mount (ATM). This unit sat astride the MDA and was configured with a quartet of electricity-producing solar panels. The OWS had a pair of solar panels as well. The entire Skylab stack weighed 85 tons.

The Skylab space station (Skylab 1) was placed into a 270-mile orbit using a Saturn V launch vehicle on Monday, 14 May 1973. Upon reaching orbit, it quickly became apparent that all was far from well aboard the space station. The micro-meteoroid shield and solar panel on one side of the OWS had been lost during ascent. The other OWS solar panel was stuck and did not deploy as planned.

With the loss of an OWS solar panel, Skylab would not have enough electrical energy to conduct its mission. The station was also heating up rapidly (temperatures approached 190 F at one point). The lost micro-meteoroid shield also provided protection from solar heating. Sans this protection, internal temperatures could rise high enough to destroy food, medical supplies, film and other perishables and render the OWS uninhabitable.

NASA engineers quickly went to work developing fixes for Skylab’s problems. A mechanism was invented to free the stuck solar panel. A parasol of gold-plated flexible material, deployed from an OWS scientific airlock, was then fashioned and tested on the ground. This material would cover the exposed portion of the OWS and provide the needed thermal shielding.

The onus was now on the Skylab 2 crew of Conrad, Kerwin and Weitz to implement the requisite fixes in orbit. On Friday, 25 May 1973, the Skylab 2 crew and their Apollo Command and Service Module (CSM) were rocketed into orbit by a Saturn IB launch vehicle. They quickly rendezvoused with Skylab and verified its sad condition. It was time to get to work.

The first order of business was to try to free the stuck solar panel. As Conrad flew the CSM in close proximity to Skylab, Kerwin held Weitz by the feet as the latter leaned out of the open CSM hatch and attempted to release the stuck solar panel with a pair of special cutters. No joy in spaceville. The solar panel refused to deploy.

The Skylab 2 crew next attempted to dock with Skylab. They tried six times and failed. The CSM drogue and probe was not functioning properly. The crew had to fix it or go home. With great difficulty, they did so and were finally able to dock with Skylab. The overriding objective now was to enter Skylab and successfully deploy the parasol thermal shield.

With Conrad remaining in the CSM, Kerwin and Weitz sported gas masks and cautiously entered Skylab. The temperature inside of the OWS was 130 F. Fortunately, the air was found to be of good quality and the pair went to work deploying the thermal shield through a scientific airlock. The deployment was successful and the temperature started to slowly fall.

It would not be until Thursday, 07 June 1973 that the stuck solar panel would finally be freed. On that occasion, Conrad and Kerwin donned EVA suits and spent 8 hours working outside of Skylab. Their initial efforts with the cutters were unsuccesful.

Undeterred, Conrad and Kerwin improvised and were able to cut the strap that restrained the solar panel. Then, heaving with all their might, the pair finally freed the solar panel. In obedience to Newton’s 3rd Law, as the solar panel deployed in one direction, the astronauts went flying in the other. Happily, they were able to collect themselves and safely reenter the now adequately-powered Skylab.

Skylab 2 went on to spend 28 days in orbits; a record for the time. This record was quickly eclipsed by the Skylab 3 and Skylab 4 crews which spent 59 and 84 days in space, respectively. Skylab was an unqualified success and provided a plethora of terrestrial, solar and human factors data of immense importance to space science. These data played a vital role in the design and development of the ISS.

Skylab was abandoned following the Skylab 4 mission in February of 1974. The plan was to reactivate it and raise its orbit using the Space Shuttle when the latter became operational. Unfortunately, a combination of a rapidly deteriorating orbit and delays in flying the Shuttle conspired against bringing this plan to fruition. Skylab reentered the Earth’s atmosphere and broke-up near Australia in July of 1979.

Posted in Aerospace, History

Single Combat Warrior

Fifty-eight years ago this month, United States Navy Commander Alan Bartlett Shepard, Jr. became the first American to be launched into space. Shepard named his Mercury spacecraft Freedom 7.

Officially designated as Mercury-Redstone 3 (MR-3) by NASA, the mission was America’s first true attempt to put a man into space. MR-3 was a sub-orbital flight. This meant that the spacecraft would travel along an arcing parabolic flight path having a high point of about 115 nautical miles and a total range of roughly 300 nautical miles. Total flight time would be about 15 minutes.

The Mercury spacecraft was designed to accommodate a single crew member. With a length of 9.5 feet and a base diameter of 6.5 feet, the vehicle was less than commodious. The fit was so tight that it would not be inaccurate to say that the astronaut wore the vehicle. Suffice it to say that a claustrophobic would not enjoy a trip into space aboard the spacecraft.

Despite its diminutive size, the 2,500-pound Mercury spacecraft (or capsule as it came to be referred to) was a marvel of aerospace engineering. It had all the systems required of a space-faring craft. Key among these were flight attitude, electrical power, communications, environmental control, reaction control, retro-fire package, and recovery systems.

The Redstone booster was an Intermediate Range Ballistic Missile (IRBM) modified for the manned mission. The Redstone’s up-rated A-7 rocket engine generated 78,000 pounds of thrust at sea level. Alcohol and liquid oxygen served as propellants. The Mercury-Redstone combination stood 83 feet in length and weighed 66,000 pounds at lift-off.

On Friday, 05 May 1961, MR-3 lifted-off from Cape Canaveral’s Launch Complex 5 at 14:34:13 UTC. Alan Shepard went to work quickly calling out various spacecraft parameters and mission events. The astronaut would experience a maximum acceleration of 6.5 g’s on the ride upstairs.

Nearing apogee, Shepard manually controlled Freedom 7 in all 3 axes. In doing so, he positioned the capsule in the required 34-degree nose-down attitude. Retro-fire occurred on-time and the retro package was jettisoned without incident. Shepard then pitched the spacecraft nose to 14 degrees above the horizon preparatory to reentry into the earth’s atmosphere.

Reentry forces quickly built-up on the plunge back into the atmosphere with Shepard enduring a maximum deceleration of 11.6 g’s. He had trained for more than 12 g’s prior to flight. At 21,000 feet, a 6-foot drogue chute was deployed followed by the 63-foot main chute at 10,000 feet. Freedom 7 splashed-down in the Atlantic Ocean 15 minutes and 28 seconds after lift-off.

Following splashdown, Shepard egressed Freedom 7 and was retrieved from the ocean’s surface by a recovery helicopter. Both he and Freedom 7 were safely onboard the carrier USS Lake Champlain within 11 minutes of landing. During his brief flight, Shepard had reached a maximum speed of 5,180 mph, flown as high as 116.5 nautical miles and traveled 302 nautical miles downrange.

The flight of Freedom 7 had much the same effect on the Nation as did Lindbergh’s solo crossing of the Atlantic in 1927. However, in light of the Cold War fight against the world-wide spread of Soviet communism, Shepard’s flight arguably was more important. Indeed, Alan Shepard became the first of what Tom Wolfe called in his classic book The Right Stuff, the American single combat warrior.

For his heroic MR-3 efforts, Alan Shepard was awarded the Distinguished Service Medal by an appreciative nation. In February 1971, Alan Shepard walked on the surface of the Moon as Commander of Apollo 14. He was the lone member of the original Mercury Seven astronauts to do so. Shepard was awarded the Congressional Space Medal of Freedom in 1978.

Alan Shepard succumbed to leukemia in July of 1998 at the age of 74. In tribute to this American space hero, naval aviator and US Naval Academy graduate, Alan Shepard’s Freedom 7 spacecraft now resides in a place of honor at the United States Naval Academy in Annapolis, Maryland.

Posted in Aerospace, History
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