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Science / Space Race

[November 16, 1966] A Grand Finale (Gemini 12)

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by Kaye Dee

As I write, it’s less than a day since the splashdown of Gemini 12 brought NASA’s second manned spaceflight programme to an overwhelmingly successful conclusion, demonstrating that the Space Agency has finally mastered the art of spacewalking. It’s incredible to think that it’s only been 20 months since the first manned Gemini mission was launched, but the packed schedule of ten flights has tested out all the techniques that the space agency needs to advance to its Apollo lunar programme.

Two for the Show

Gemini 12's Command Pilot was former Naval aviator Captain Jim Lovell (left in photo above). Making his second spaceflight, Lovell previously flew on the Gemini 7 long duration mission and now holds the record for the longest time spent in space by any astronaut or cosmonaut. Pilot for this mission was rookie astronaut USAF Major Edwin “Buzz” Aldrin, who performed an unprecedented three successful extravehicular activities (EVAs) during this flight. The only member of the astronaut corps to hold a Doctorate, Aldrin is a specialist in rendezvous and docking techniques, and on this mission he put that knowledge to very good use.

A “Halloween” Patch

Gemini 12 was originally scheduled to launch on October 31, so Lovell and Aldrin had considered a Halloween theme for their mission patch. They wanted to evoke Halloween with the use of orange and black colours and also planned to show their Gemini capsule launched on a witch’s broomstick instead of a rocket! However, with the launch rescheduled to November, only the Halloween colour-scheme remained of the original concept.

The final design features the Roman numeral XII at the top of the round patch, in the position it would be on a clock-face. Just like an hour hand, the Gemini spacecraft points to the XII, a reminder that this is the final flight of the Gemini programme. The crescent Moon on the left side of the patch symbolises the ultimate goal of the upcoming Apollo programme.

Training for Weightlessness

Gemini 12's main goal was to complete three EVAs that would demonstrate that NASA had finally cracked the problem of successfully carrying out spacewalking operations, a technique crucial to the Apollo programme.

The astronauts who attempted to perform spacewalks on Gemini 9, 10 and 11, had all reported that operating in orbit was much more difficult and tiring than the simulations conducted using the KC-135 weightlessness training aircraft. They also complained that there were few handholds on the exterior of the Gemini and Agena to help them move around in Zero-G. Consequently, a new approach to training was employed for Gemini 12, which I understand was suggested by Astronaut Aldrin himself, who is a keen scuba diver.


"Buzz" Aldrin practices installing a handrail between the Gemini capsule and Agena target vehicle, in an underwater training simulation

In addition to the KC-135 flights, Aldrin trained in a large pool containing a Gemini mockup. In the pool, special weights were added to the astronaut’s spacesuit to create “neutral buoyancy,” offsetting gravity so he would neither rise nor sink, and Aldrin spent several EVA simulation training sessions of more than two hours underwater.

As well as this new training technique, more handrails and handholds were added to the Gemini capsule, along with a waist tether that would enable Aldrin to turn wrenches and retrieve experiment packages without too much effort.

Dr. Rendezvous Saves the Day, Again!

After two delays caused by technical issues, the final Gemini mission lifted off on the afternoon of November 11 US time. On its third orbit, Gemini 12 prepared to dock with the Agena target vehicle, but problems with the Gemini's onboard radar threatened to make that impossible.

Luckily, Aldrin had already developed procedures for onboard backup rendezvous techniques in the event of radar failure. Drawing on his expertise, Aldrin used a sextant and his slide rule, measuring the angle between the horizon and the Agena. Once he had confirmed the information with his rendezvous chart, Aldrin calculated corrections with the spacecraft’s computer, enabling the rendezvous and docking to be successfully accomplished.

Rendezvous with the Sun

Despite the successful rendezvous, some anomalies with the Agena’s turbopump during launch led to Mission Control cancelling a planned boost to a higher orbit, like that conducted on Gemini 11. Instead, NASA took the opportunity to have the crew photograph a solar eclipse through the spacecraft windows at the beginning of mission day two.

Using the Agena’s secondary propulsion system, Gemini 12 changed orbits to place itself above South America at the right time and location to capture the first colour images of a total solar eclipse free from the interference of the Earth’s atmosphere. During the scant eight seconds that the astronauts could view the eclipse, they snapped four images that are expected to help scientists discover the secrets of the solar corona. The pictures were taken with film sensitive to ultra-violet light, which does not penetrate through the Earth's atmosphere.

Standing Up in Space

About two hours after photographing the eclipse, Aldrin commenced his first EVA, with his head and upper body exposed to space as he stood in the open hatch above his spacecraft seat. During this “stand-up EVA”, which lasted almost two and a half hours, Aldrin took the time to accustom himself to the space environment, which it was thought would better prepare him for his later spacewalk.

One of his first jobs was to install a handrail between his hatch and the docking collar of the Agena that would aid his movements during his day three spacewalk. Aldrin mounted a camera on the side of the spacecraft, with which he took a close-up picture of himself (above), the first shot of its type ever taken! He collected a micrometeorite experiment, and took photographs of the Earth as well as ultra-violet astronomical photography.

Aldrin’s photographic tasks were part of the 14 scientific, medical, and technological experiments planned for Gemini 12. Although five experiments could not be fully completed, those that were included: frog egg growth under zero-g conditions; synoptic terrain and weather photography; airglow horizon photography; and UV astronomy and dim sky photography.

Walking and Working in Space

Gemini 12 flight day three began with some minor fuel cell and manoeuvring thruster issues that would last for the rest of the mission. They did not, however, prevent the highlight of the flight from taking place: a planned two hour tethered spacewalk by Major Aldrin. Until Gemini 12, successfully performing work outside a spacecraft was the one Gemini objective that had eluded NASA, but Aldrin exceeded even the most optimistic hopes for this flight as he performed a record two hours, nine minute and 25 second EVA.

Attached to a 30-foot umbilical cord, Aldrin used the handrail he had installed the day before to assist in attaching a 100-foot long tether between the nose of the Gemini and the Agena. With the handholds, he did not experience the problems Gordon encountered on Gemini 11. Aldrin’s approach to his spacewalk was to go slowly and carefully, resting for two-minute periods between tasks. In fact, about a dozen two-minute rest periods were built into the EVA schedule to prevent Aldrin from becoming exhausted like previous Gemini spacewalkers. 

Moving to the spacecraft’s aft adapter, Aldrin supported himself with overshoe restraints and waist tethers to carry out a number of work tasks. He was able to fasten rings and hooks, connect and disconnect electrical and fluid connections, tighten bolts and cut cables. Aldrin then moved across to the Agena, where he worked at pulling apart electrical connectors and putting them together again. He also tried out a torque wrench designed for the Apollo programme.

At the completion of his spacewalk, Aldrin returned to his Gemini seat with no fatigue and all his tasks accomplished. This demonstrated that the use of neutral buoyancy training, available handholds and foot restraints on the spacecraft, and a slow and measured pace of work while in space, are the ingredients needed for future successful EVAs during the Apollo missions. 

Going for a Spin

The other major task for flight day three was a repeat of the gravity-gradient stabilisation/artificial gravity experiment performed on Gemini 11. Undocking from the Agena, Gemini 12 moved to the end of the tether connecting the two vehicles and then fired its thrusters to slowly rotate the combined spacecraft. Although they had some difficulty keeping the tether taut, the astronauts were able to use centrifugal force to generate a small amount of gravity during the four hour, 20 minute exercise, and achieve gravity-gradient stabilization. After releasing the tether connected to the Agena, Gemini 12 pulled away from the target vehicle and did not re-dock with it again.

One More Time

The last day of Gemini 12’s mission began with an attempt to sight two yellow clouds of sodium particles ejected by a pair of French Centaure rockets launched from the Algerian Sahara. This experiment was designed to measure high altitude winds. Although Lovell and Aldrin could not see the clouds, they did attempt to photograph them using directional instructions from the ground. We’ll have to wait until those films are developed to see if they were successful.

Shortly afterwards, as the spacecraft came over Australia, Gemini 12’s hatch opened for the final time, and Aldrin conducted a second stand-up EVA. Lasting 55 minutes, this brought Aldrin’s total spacewalking time up to a record five hours and 30 minutes! Most of this EVA occurred as Gemini 12 passed over the night side of the Earth, so that Aldrin could aim his camera at “hot young stars”, which have stimulated the curiosity of astronomers all over the world. He also took numerous ultraviolet photographs of stars and constellations.

Mission Accomplished

After a spaceflight lasting 94 hours, 34 minutes and 31 seconds, Geminin 12 made the second computer-controlled re-entry of the programme, splashing down safely in the western Atlantic just three miles from their target, near the recovery aircraft carrier USS Wasp.

Captain Lovell and Major Aldrin have now been recovered and are on their way back to the United States for post-flight debriefing. But we already know that the Gemini 12 mission has been a fitting grand finale to the Gemini project, clearly demonstrating that NASA has achieved all the goals it set for the programme: it has now mastered rendezvous and docking, direct ascent to orbit rendezvous, long-duration spaceflight equivalent to the time of an Apollo lunar mission, and – the trickiest of all, as they discovered – the art of spacewalking.

We should not forget that Gemini has been a team effort, directly involving more than 25,000 people from NASA, the US Department of Defence, other government agencies, universities and research centres, industry and tracking station partners overseas. Everyone involved should feel great pride in the way spaceflight has been advanced in an amazingly short time.

Very soon, the manned Apollo programme will commence, and we can all hope that it will lead to a successful landing on the Moon before the end of this decade. But we should not forget that its success will stand on the shoulders of the Gemini programme.

Postscript

But where are the Russians in the race to the Moon? No Soviet manned flight has been announced since Voskhod 2 in March last year. Has the USSR withdrawn from the race? That seems unlikely, but why do they appear not to have attempted rendezvous and docking missions? Perhaps they have decided to use a different method of reaching the Moon, such as direct ascent, using a massive multi-stage rocket, without the need for orbital rendezvous? After all, as far as we can tell, they still have larger and more powerful rockets than Western nations. Only time will tell, but I think there are still many surprises in store from the USSR before either the East or West wins the Space Race!

(Want more exciting space stories?  Join us for Star Trek tomorrow night at 8:30 PM (Pacific AND Eastern — two showings)!!)

Here's the invitation!



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Science / Space Race

[September 18, 1966] Soaring Higher (Gemini 11)

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by Kaye Dee

Back in July, Gemini 10 accomplished an incredibly ambitious mission, and I wondered then what the next Gemini flight could do to top it. Now we know. In its three-day mission, Gemini 11 carried out a packed program: it made a direct ascent to its Agena target vehicle, soared even higher than its predecessor, conducted two EVAs and 12 different experiments, created artificial gravity and even performed the first computer-controlled return to Earth. I’m exhausted just listing all these highlights!


Gemini-11 prime and backup crews (L to R): William A. Anders, backup crew pilot; Richard F. Gordon Jr., prime crew pilot; Charles Conrad Jr. (foot on desk), prime crew command pilot; and Neil A. Armstrong, backup crew command pilot

Anchors Aweigh!

You could almost say that Gemini 11 has been a US Navy mission, since both its crew are naval officers. The Command Pilot, Commander Charles “Pete” Conrad Jr., was selected in the second astronaut group in 1962. He was previously the Pilot for the then-record breaking Gemini 5 mission, spending almost 8 days in space. Making his first spaceflight, Gemini 11 Pilot L.t Commander Richard “Dick” Gordon Jr. was part of NASA’s third astronaut intake in October 1963. Both men were previously naval aviators and test pilots.

There’s also a nod to the crew’s US Navy background in their mission patch, which was designed in Navy colours of blue and gold. The major milestones of the mission are indicated by stars. The first orbit rendezvous with the Agena is indicated by the tiny star on the line representing the mission’s low Earth orbit, while the actual docking is marked by the large star on the left. The star at the top marks the plan to reach a record high apogee, and the star on the right signifies Astronaut Gordon's spacewalk. The three events symbolised by the three large stars are also depicted visually, with representations of the docked Gemini 11 and Agena, a gold line representing the high apogee orbit and a spacewalking astronaut. The Roman numeral XI soars above the Earth from the launch site in Florida.

Preparing for Apollo

An important goal of Gemini 11 was to prove the feasibility of the plan for direct ascent rendezvous on Apollo lunar missions, in which a returning Lunar Module will lift off from the Moon’s surface to rendezvous with the Command Module as it passes overhead. To practice this technique, Gemini 11 would attempt to rendezvous directly with its Agena target vehicle on its first orbit, rather than taking around four orbits, as has been the case on earlier Gemini flights. To achieve this manoeuvre, the Atlas-Agena target vehicle had to launch within the desired time, while the Gemini itself had only a two-second launch window!

Present and future in one picture. As Gemini 11 lifts off from the Cape Kennedy Air Force Station's Launch Complex 19, the first Apollo Saturn V rocket is on Launch Complex 39A at Kennedy Space Centre. This Saturn V is a non-flight Facility Verification Vehicle that is being used for pad fit checks

Although technical issues twice delayed the launch, Gemini 11 finally lifted off exactly on time 12 September (US time): its target vehicle had been launched an hour and 37 minutes earlier. Manoeuvres for Gemini to catch up with the Agena began quickly, and before its first orbit had been completed, Gemini 11 was flying in formation with its target and ready to dock. The actual docking was achieved nine minutes after rendezvous, just one hour and 34 minutes after liftoff. With an achievement like this, it’s amazing to think that the first rendezvous between two orbiting spacecraft occurred only nine months ago! Unlike Gemini 10, the Gemini 11 docking consumed less fuel than expected and both Commander Conrad and Lt. Commander Gordon conducted two docking exercises with the Agena, before a final manoeuvre established the docked spacecraft in a 178 x 188 mile orbit.


After a first orbit rendezvous, Gemini 11 is docked with its Agena. The target vehicle's antenna is seen extending upwards

“Ride ‘em Cowboy”

The first Extra-Vehicular Activity of the mission occurred 24 hours after launch, when Astronaut Gordon left the spacecraft to begin a spacewalk that was scheduled to last about 105 minutes, while he remained tethered to Gemini 11 by a life support umbilical line. After setting up a movie camera and retrieving a micrometeorite experiment, the next task involved fastening a 100-foot tether, stored in the Agena's docking collar, to a docking bar on the Gemini's nose. These would be used for experiments in passive stabilisation and the first creation of artificial gravity in space (see below!)


"Ride 'em cowboy," said Gemini 11 Command Pilot Conrad as Astronaut Dick Gordon rested on the Agena target vehicle. This view was taken over the Atlantic Ocean at approximately 160 miles above Earth

Like previous Gemini EVAs, working in space for an extended period proved more tiring than in the simulations and Gordon became exhausted, overstressing his spacesuit’s life support system. After attaching the tether, he stopped to rest, sitting astride the Agena, like a cowboy riding a bucking bronco. Heavy perspiration inside the suit obscured the astronaut’s vision, virtually blinding his right eye and the faceplate of his helmet became fogged due to heavy breathing. As a result, the EVA was terminated, with Gordon spending just 21 minutes outside the spacecraft. 

Reaching New Heights

On 14 September, more than 40 hours into the mission, the Agena target vehicle’s primary propulsion system was fired for 25 seconds to thrust the docked spacecraft to a maximum altitude of 853 miles, establishing a new manned spaceflight altitude record! The Gemini 11 crew were enthralled by the spectacular view from this unprecedented vantage point. They particularly commented on the blueness of the water and marked curvature of the Earth below them.


Conrad and Gordon reached the maximum altitude of their high orbit over the southern hemisphere. As they looked west over the western half of Australia, Conrad said "We're looking straight down over Australia now. We have the whole southern part of the world out one window. Utterly fantastic."

After two orbits at this record-breaking altitude, completed in 3 hours, 23 minutes, Conrad and Gordon once again used the Agena’s engines to drive the joined spacecraft back down to their original low Earth orbit.

Standing Up in Space

On flight day three, Astronaut Gordon performed the mission’s second EVA, a “stand-up" spacewalk like that conducted on Gemini 10. Positioned in the open hatch, standing on his seat, Gordon spent two hours and eight minutes photographing the Earth, clouds and stars, as part of the range of experiments to be performed during the flight. During this period, Conrad manoeuvred the spacecraft to point Gordon and his camera in whatever direction was required. Unlike his first EVA experience, Gordon found the “stand-up” spacewalk so peaceful that he actually fell asleep!


Astronaut Dick Gordon stands in the open spacecraft hatch during the Gemini 11 mission

Inflight Experiments

The photography that Gordon undertook during his “stand-up” EVA were part of a packed program of 12 scientific experiments planned for Gemini 11. These included photography of the Earth for research in geology, geophysics, geography, oceanography, and related fields, and photography of clouds to study the fine structure of the Earth's weather system. Other experiments focused on astronomy and upper-atmosphere studies, while three experiments had specific military applications. There was a biological experiment looking at whether weightlessness enhances the effects of radiation on human white blood cells and Neurospora crassa fungi. An interesting photographic experiment investigated the regions of the L4 and L5 libration points of the Earth–Moon system. These are zones trailing and ahead of the Moon's orbit that are gravitationally stable. It is theorized that there might be clouds of particulate matter, or even tiny mini-Moons, which it is theorised may be orbiting the Earth in these regions.

Making Artificial Gravity!

After the stand-up EVA, 50 hours into the mission, Gemini 11 commenced a fascinating experiment in creating artificial gravity. Undocking from the Agena target vehicle, the Gemini 11 spacecraft slowly manoeuvred to stretch out the tether that Gordon had connected between them during his first spacewalk, and then allow the two tethered spacecraft to slowly rotate around one another.

The movement of the tethered spacecraft was first erratic, but stabilised after about 20 minutes, so that the rotation rate could then be increased. The astronauts found it challenging to keep the rope tether between the spacecraft tight, but they were able to demonstrate the "passive attitude stabilisation" of two spacecraft connected by a tether.


While tethered to their Agena target vehicle, the Gemini 11 crew manoeuvred their craft to keep the tether taut between the two. By firing their side thrusters to slowly rotate the combined spacecraft, they were able to use centrifugal force to generate about 0.00015 g of artificial gravity

The circular motion at the end of the tether created a slight artificial “gravitational acceleration” within Gemini 11. This is the first time artificial gravity has been demonstrated in space, even though that gravitational force was only 1.5 one-thousandths that of Earth. After about three hours, the rope tether was released, and the spacecraft moved apart.

Final Rendezvous

Although a fuel cell failed after the artificial gravity experiment, the remaining fuel cells were able to satisfactorily cope, and just under five hours before planned re-entry, Gemini 11 made a final “flyby” rendezvous with the Agena. This last rendezvous had not been part of the original flight plan but was made possible because of the fuel efficiency of the earlier rendezvous and docking manoeuvres. The fact that this rendezvous was made without use of the rendezvous radar, which had malfunctioned, is a testament to the skill and training of the Gemini 11 crew.


Gemini 11's Agena target vehicle seen during the "flyby" rendezvous. The tether from the artificial gravity and passive stabilisation experiment can be seen still attached to the vehicle

Coming Home Under Computer Control

Gemini 11’s return to Earth was the first fully automatic splashdown in the history of the US space program. On 15 September, at the end of its 44th orbit, Gemini 11’s retro-rockets were fired and the automatic re-entry was accomplished by computer commands directly to the thrusters. On earlier Gemini missions, the Command Pilot took controls of the re-entry at about 75 miles up, using the spacecraft's offset centre of gravity to generate lift for changes in direction. For Gemini 11, these manoeuvres were accomplished by computer commands. This process proved successful, and the capsule splashed down only 1.5 miles from the planned position in the Atlantic Ocean. A helicopter from the USS Guam picked up Conrad and Dick Gordon, taking the astronauts to the recovery ship.


Command Pilot Conrad climbs from Gemini 11 minutes after its successful computer-controlled splashdown

Heading to a Grand Finale

With Gemini 11, NASA demonstrated that it has has well and truly mastered rendezvous and docking. But the difficulties encountered by Lt Commander Gordon on his first EVA, and the problems that occurred on the spacewalks in previous missions, show that Extra-Vehicular Activity remains a challenge to be conquered. EVA is vital to the success of the Apollo programme, so Gemini 12, the final mission in this programme, will have spacewalking as its primary objective: it will be a grand finale indeed if Gemini 12 can demonstrate that the problems of EVA, like those of rendezvous and docking, have been successfully solved.




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Science / Space Race

[July 24, 1966] Doubling Up (Gemini 10)

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by Kaye Dee

A few days ago, Gemini 10 returned from the most ambitious US spaceflight to date. It literally took the Gemini programme to new heights and has firmly cemented the United States’ lead over the Soviet Union in the race to the Moon. Featuring not one, but two orbital rendezvous and two EVAs, Gemini 10 was a complex mission designed to increase NASA’s experience with these two techniques vital to the success of the Apollo lunar programme.

Designed by astronaut John Young’s wife Barbara, the Gemini 10 patch is simple, but highly symbolic. It features the Roman numeral 10 and two stars representing the two rendezvous attempts; Castor and Pollux (the two brightest stars in the constellation Gemini); and the two crew members. A stylized rendezvous is also depicted.

Crew for a Complex Mission

The Command Pilot for Gemini 10 was US Navy Commander John Young (left in the picture below), making his second spaceflight after acting as the Pilot of Gemini 3. Sitting in the right-hand seat as Pilot was US Air Force Major Michael Collins. A member of NASA’s third astronaut group, he is the first astronaut born outside the United States: his father is an Army officer and was stationed in Rome at the time of Collins’ birth.

Critical Timing

Blasting off on July 18, Gemini 10 was the first dual launch of a target vehicle and a manned Gemini flight to occurr exactly as planned. Launch timing was crucial, as Gemini 10 had only a 35-second window if it was going to rendezvous with two Agena targets in different orbits. The launch of the first rendezvous target, Agena 10, could not be delayed by more than 28 minutes, or it would result in a two-day wait until the second Agena already in orbit (originally launched for Gemini 8) would again be in position for the dual rendezvous plan to succeed. Agena 10 lifted off just two seconds late. One hundred minutes later it was followed by Gemini 10, launching exactly on time.

An amazing timelapse photo of Gemini 10's launch, showing the supporting rocker arm tower falling away

First Rendezvous

Despite the perfect launch, the path to Gemini 10’s first rendezvous was not completely smooth. An error made by John Young during the second burn – needed to rendezvous with the Agena about 160 miles above the Earth – required two additional burns to correct. By the time Gemini 10, on its fourth orbit, rendezvoused and docked with Agena 10, 60% of its fuel had been consumed. This placed constraints on the remainder of the mission, leading to the cancellation of several scheduled scientific experiments and additional docking practice.

Fortunately, the docking itself was successful and Mission Control decided to keep Gemini 10 docked to the Agena as long as possible. The target vehicle carried 3,400 pounds of fuel, some of which could be used for attitude control of the docked vehicles.


Docked to the nose of Agena 10, Gemini 10 Pilot Michael Collins took this impressive photograph of the Agena's engine firing as it boosted them to a record altitude

Rocketing to New Heights

Most of that fuel was needed for the second phase of Gemini 10’s mission. About seven and a half hours after launch, an 80 second burn of the Agena engine hurtled Young and Collins to an altitude of 474 miles, the farthest anyone has so far been from the Earth. This new record completely eclipses the previous record of 310 miles set by Voskhod 2 last year.

As the Gemini was docked nose-to-nose with the Agena, Young and Collins were flying ‘backwards’ as the rocket thrust them towards the higher altitude in a wild ride. Despite their unique vantage point, much of the view from the crew’s windows was blocked by the bulk of the Agena in front of them, so Young and Collins took very few photos: instead, they concentrated on their spacecraft’s instruments, especially the radiation dosage. The crew was particularly concerned about the radiation levels at their record-breaking altitude, as the lower edge of the inner Van Allen radiation belt was only about 150 miles above them. Fortunately, their instruments showed that the radiation levels at that altitude posed no danger to human life.


One of the few photos taken by the Gemini 10 crew at their record altitude, showing the curvature of the Earth. The Straits of Gibraltar are visible, with Europe to the left and North Africa to the right

Speaking of radiation, while Gemini 10 was orbiting aloft, France tested another nuclear weapon at Mururoa Atoll in the South Pacific. Although the astronauts were high too high above the blast zone for radiation to be an issue, Young and Collins were warned not to look at its blinding flash as they passed overhead.

When is a Spacewalk not a Spacewalk? When It’s a “Standup EVA”!

The Gemini crew began their second day in space with the news that they had enough fuel to complete the next phase of their mission, the rendezvous with Gemini 8’s Agena target vehicle. Another wild ride, pushed by Agena 10, lowered the Gemini to a new orbit with an apogee of 237 miles. Now the crew began to prepare for the mission’s first EVA, which would not see an astronaut actually leave the spacecraft. 

As an orbital sunset approached, Collins opened his hatch, exposing both astronauts to the space environment to perform a “standup EVA”. Standing in his seat with the upper part of his body outside the spacecraft, for a view unconstrained by its small windows, Collins commenced a photographic study of stellar ultraviolet radiation. He took 22 images of the southern Milky Way, scanning from Beta Crucis to Gamma Velorum (though, unfortunately, few of the images have proved scientifically usable). As Gemini 10 passed from night back to day, Collins also photographed a colour patch on the exterior of the spacecraft, to see if film could accurately reproduce colors in space. This task was cut short, though, when both Collins and Young experienced an eye irritation that caused their eyes to tear, making it difficult to see. As I write this article, the cause of this irritation is still uncertain, although it is thought to be a leak of lithium hydroxide in the environmental system.

Second Rendezvous

Gemini 10’s third day in space was its most complex and hazardous, commencing with the rendezvous with Agena 8. For the final time, Agena 10 fired its engine, to bring the docked spacecraft within 70 miles of Agena 8. At this point Gemini 10 discarded the Agena, which remains in orbit for use as a target by a future Gemini mission. Gemini 10 continued under its own power, for the first time in almost 48 hours, to reach Agena 8.

The former Gemini 8 target, having been in space since March, was essentially dead, without any power. Commander Young completed the critical final stage of rendezvous without the help of bright running lights and target radar, while trying to conserve enough fuel to let Collins take a one-hour spacewalk. He successfully guided the Gemini to within 10 feet of Agena 8, maintaining station close to the target vehicle without docking. This unique rendezvous simulated the rescue of astronauts from a spacecraft that had lost all electrical power.

A “Working” Spacewalk

With enough maneouvring fuel still available, Collins’ second EVA was now Go! Dubbed a “working spacewalk”, this EVA involved activities around the exterior of Gemini 10 and a traverse across to Agena 8. Like Gene Cernan on Gemini 9, Major Collins experienced difficulties in conducting his EVA tasks, demonstrating the need for more hand- and footholds on the exterior of future space vehicles. Nevertheless, he retrieved a micrometeorite collector from the exterior of the Gemini, containing experiments from Britain, Israel and West Germany. Unfortunately, this collector was later lost in space, apparently floating out of the spacecraft before the final hatch closing. 

Another micrometeorite collector was located on Agena 8. After one failed attempt to retrieve it, Collins used an experimental nitrogen-propelled “jet gun”, the Hand-Held Maneuvering Unit, to propel himself back to the Agena. This time he successfully retrieved the micrometeorite experiment, which is of particular scientific interest because of its long duration in orbit. There are no photos of the spacewalk available, but these training images give some idea of the complexity of the operations. However, low propellant quantity curtailed the spacewalk after only 39 minutes, instead of the originally planned hour. The crew experienced some difficulty in closing the hatch, due to the snake-like 50-foot umbilical used for Collins’ spacewalk and it was later jettisoned, along with the chestpack used by Collins and some other equipment an hour later. 

Return to Earth

About 63 hours into the flight, Young and Collins awoke to homecoming day, completing some final experiments, mostly involving photography of the Earth. Then, 70 hours and 10 minutes after liftoff, re-entry commenced and Young steered Gemini 10 to a pinpoint landing in the Atlantic only three and a half miles from the aiming point. The crew of the prime recovery vessel, the USS Guadalcanal, watched the spacecraft hit the water, as did millions of television viewers via the Early Bird satellite (though not us here in Australia, as we do not yet have access to satellite communications: it’s coming soon, though!).


For the first time the children of the recovery ship crew were allowed to be aboard to watch the splashdown and recovery. Here they join the party celebrating Gemini 10's safe return from a record-setting mission

Gemini 10 was certainly a mission for the record books: I can’t wait to see what further developments Gemini 11 will bring in just a couple of months’ time.




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Science / Space Race

[March 18, 1966] Taking Gemini for a Spin (Gemini 8)

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by Kaye Dee

As the race for the Moon heats up, the Gemini program is moving forward at a cracking pace –three months ago, Gemini VII completed its record breaking long-duration mission and NASA’s latest manned space mission, Gemini VIII launched just two days ago on March 16 (US time). By co-incidence, this was right on the 40th anniversary of the first successful launch of a liquid-fuelled rocket by American physicist Dr. Robert Goddard.


Goddard and his first liquid fuel rocket, launched forty years to the day before Gemini VIII. Developing a liquid-fuelled rocket was the necessary first step to making spaceflight a reality

But are things moving too fast? This latest Gemini flight was one of NASA’s most ambitious to date, slated for a 3-day mission to carry out the first rendezvous and docking and the United States’ second spacewalk. However, it was prematurely cut short after about 10 and a half hours, due to an in-flight emergency.

What was Supposed to Happen

Gemini VIII was intended to carry out the four rendezvous and docking manoeuvres originally planned for Gemini VI (the goals of that mission had to be changed due to the loss of its Agena target vehicle and instead it rendezvoused with Gemini VII). Being able to rendezvous and dock two spacecraft is a technique that is vitally important for the success of the Apollo programme, so NASA needs to be sure that it can reliably carry out these manoeuvres.


Gemini VIII approaches its Agena target vehicle in preparation for docking, practicing one of the crucial technologies of the Apollo programme

NASA also needs to gain more experience with extra-vehicular activity (EVA), or spacewalking, which is another crucial technique needed for Apollo. So far, the Gemini programme’s only EVA has been the one carried out by Ed White during the Gemini IV mission in June last year. Astronaut David Scott was scheduled to perform an ambitious spacewalk of over two hours, operating at the end of a 25-foot tether. He was supposed to retrieve a radiation experiment from the front of the Gemini's spacecraft adapter and activate a micrometeoroid experiment on the Agena target vehicle. Then it was planned to test a space power tool by loosening and tightening bolts on a work panel attached to the Gemini.

The most exciting part of the spacewalk would have taken place after Mission Commander Neil Armstrong undocked from the Agena for the first time. Major Scott would have tested an Extravehicular Support Pack (ESP), which contained its own oxygen supply and propellant for his Hand-Held Manoeuvring Unit. A 75-foot extension to his tether would have enabled Scott to carry out several manoeuvres in conjunction with the Gemini and Agena vehicles, while separated from them at distances up to 60 feet.

Very Experienced Rookies


Neil Armstrong (front) and David Scott departing the suit up trailer on their way to the launch pad. Behind Scott is Chief Astronaut Alan Shepard, the first American in space.

Gemini VIII’s crew are both first-time astronauts, but they have a wealth of flight experience between them. Mission Commander Neil Armstrong is the first American civilian in space, and a highly experienced test pilot. Before being selected for NASA’s second group of astronauts, Mr. Armstrong was a Naval aviator during the Korean conflict and then an experimental test pilot with NASA’s predecessor the National Advisory Committee for Aeronautics, which he joined in 1955. He developed a reputation as an excellent engineer, a cool-headed clear-thinker, and an outstanding test pilot with nerves of steel, all of which helped him survive a number of dangerous flight-test incidents. Included in his experience are seven flights aboard the X-15 hypersonic research aircraft.

Gemini VIII Pilot David Scott is a major in the US Air Force, and the first member of the third astronaut group to make a spaceflight. Scott saw active duty in Europe before gaining both a Master of Science degree in Aeronautics/Astronautics and the degree of Engineer in Aeronautics/Astronautics from MIT in 1962. He joined the US Air Force Test Pilot School at Edwards Air Force Base in 1962 and was selected as an astronaut in October 1963. 

A Spectrum of Objectives


Gemini VIII's mission patch. Look closely at the spectrum to see the text.

Now that mission patches seem to have become a standard part of each Gemini flight (after being introduced by the Gemini V crew), Armstrong and Scott designed their mission patch to feature a colour spectrum, which is shown as being produced by the light of two stars – Castor and Pollux, the two brightest stars in the constellation of Gemini – refracted through a prism. The spectrum symbolises “the whole spectrum of objectives” that they planned to accomplish on Gemini VIII, which included various science and technology experiments in addition to the docking and spacewalking activities. Looking closely at the spectrum, you can see that its lines have been drawn to represent the astronomical symbol for the constellation Gemini, as well as the Roman numeral VIII.

Things Go to Plan

The original Gemini VIII plan was for a three-day mission and at first everything seemed to be going perfectly. One hundred minutes before Gemini VIII, an Atlas rocket lifted off from Launch Pad 14 at the Cape carrying the Agena target vehicle. Unlike Gemini VI, this time the launch was successful, placing the Agena into a 161 nautical-mile circular orbit. Once it was certain that the Agena was safely in orbit, Gemini VIII lifted off from the nearby Pad 19: its launch, too, went without any problems.


A composite image combining the lift-off of the Atlas Agena and Gemini VIII

After an orbital “chase” of more than three and a half hours, Armstrong and Scott had their target in sight: they could visually spot it when they were about 76 nautical miles away. Then, at 55 nautical miles, the computer completed the rendezvous automatically.

Before docking with the Agena, the astronauts spent 35 minutes visually inspecting it, to ensure that it had suffered no damage from the launch. Then Armstrong started to move towards the Agena at 3.15 inches per second. In a matter of minutes, the Agena’s docking latches clicked: the first docking by a manned spacecraft had been successfully completed! Mission Commander Armstrong described the docking as “a real smoothie” and said that the Agena felt quite stable during the manoeuvre. NASA has now proved that it can achieve a critical technique needed for the Apollo Moon landings.

Things Don’t Go to Plan

The docking may have been a smoothie: however, what followed was anything but! Mission Control seems to have had some suspicions that the Agena's attitude control system could malfunction (my friends at Woomera say there was a possibility that the Agena’s onboard computer might not have the correct program stored in it), because the crew were reminded of the code to turn off the Agena’s computer and advised to abort the docking straight away if there were any problems with the target vehicle.


A close-up view as Gemini VIII approaches its Agena target vehicle.

As Gemini VIII lost radio contact with Houston (in a part of its orbit where it was out of range of any of the tracking stations on the ground), the Agena began to execute one of its stored test programs, to turn the two docked spacecraft. That’s when the emergency began! While the full details of the emergency are not yet known, it seems that the Agena started to roll uncontrollably, causing the docked spacecraft to gyrate wildly, making a full rotation every 10 seconds. The situation seems to have been pretty desperate, to judge from some communications picked up by monitors at the Radio Research Institute of the Japanese Postal Services.

Armstrong has reported that he used the Gemini capsule’s orbital attitude and manoeuvring system (OAMS) thrusters to stop the tumbling, but the roll immediately began again. As he struggled to control the rotating vehicles Armstrong noticed that the OAMS fuel dropped quickly, hinting that perhaps the problem was with the Gemini, rather than the Agena.


Diagram showing the location of the OAMS thrusters and the Re-entry Control System thrusters (incorrectly identified as "Reaction Control System")

Then They Get Worse!

Armstrong and Scott decided to undock from the Agena, apparently concerned that the high spin-rate might damage the spacecraft or possibly cause the Agena, still loaded with propellant, to rupture or explode. It turns out, though, that the Agena’s mass must have been actually damping the rotation, because as soon as Gemini VIII undocked it began to tumble even more rapidly, making almost a full end over end rotation per second! The issue was definitely with the spacecraft, and it was an extremely dangerous one. At that rate of spin, the astronauts’ vision became blurred and they have said they were in danger of blacking out!


CapCom Jim Lovell (left) and astronaut Bill Anders following reports from Gemini VIII during the crisis

It was only at this point that Gemini VIII came back into contact with Mission Control, via the tracking ship USNS Coastal Sentry Quebec, stationed southwest of Japan. Armstrong sure is a quick thinker, though. He disengaged the OAMS system and used the re-entry control system (RCS) to finally halt the spin and regain control of Gemini VIII. However, doing this used up almost 75% of the re-entry manoeuvring fuel.

Emergency Abort!

Gemini mission rules dictate that a flight has to be aborted once the RCS is activated for any reason. With so much of the RCS fuel already consumed, and with no guarantee that the tumbling might not occur again, Flight Director John Hodge (on his first mission as Chief Flight Director, too!), quickly decided to abort the mission and bring Gemini VIII back to Earth.

Hodge decided to bring Gemini VIII home after one more orbit, so that secondary recovery forces in the Pacific could be in place. Re-entry occurred over China, out of range of NASA tracking stations, but US Air Force planes spotted the spacecraft as it descended towards its landing site about 430 nautical miles east of Okinawa. Three para-rescuers were dropped to attach a flotation collar to the capsule and stay with the astronauts until the recovery ship arrived. 


Armstrong, Scott and their para-rescuers waiting for the arrival of the recovery ship

Initial reports are that, though exhausted, the crew were in good health when they landed, and they opened the Gemini hatches, ate some lunch, and relaxed in the sun with the para-rescuers while waiting for the recovery ship Leonard F Mason to arrive. Maybe the lunch wasn’t such a good idea, as I’ve heard that the crew and their rescuers were all a bit seasick by the time the ship reached them three hours later.

NASA officials met with the Gemini VIII crew in Japan for a preliminary debriefing, and Armstrong and Scott, together with Gemini VIII are now on their way back to the US. Hopefully, an accident investigation will soon reveal exactly what went wrong and why, causing NASA’s first in-flight emergency. But what we already know is that Armstrong and Scott behaved with cool competence in an extremely stressful and dangerous situation and NASA’s emergency procedures enabled the astronauts to be brought home quickly and safely. Everyone involved should be congratulated for demonstrating that even a crisis can be an important stepping-stone on the road to the Moon! 


Safe and sound aboard the U.S.S. Leonard F. Mason




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