To celebrate the 45th anniversary of the Apollo 13 mission, Universe Today is featuring “13 MORE Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.
During the first two days of the Apollo 13 mission, it was looking like this was going to be the smoothest flight of the program. As Capcom Joe Kerwin commented at 46:43 Mission Elapsed Time (MET), “The spacecraft is in real good shape as far as we are concerned. We’re bored to tears down here.”
Everything was going well, and in fact the crew was ahead of the timeline. Commander Jim Lovell and Lunar Module Pilot Fred Haise had entered the Aquarius Lunar Module 3 hours earlier than the flight plan had scheduled, wanting to check out the pressure in the helium tank – which had given some erroneous readings in ground tests before the launch. Everything checked out OK.
Opening up Aquarius early may have been one more thing that saved Apollo 13, says NASA engineer Jerry Woodfill.
“The first time the hatches between both vehicles are opened is a time consuming process,” Woodfill told Universe Today. “It’s as though a bank teller is requested to provide a customer access to a safety deposit box behind two locked vault doors.”
The removable hatch in the Odyssey Command Module had to be tied down and stowed before entering the tunnel for access to the second door, the lander’s entry hatch. Time was required for pressure equalization process so that the tunnel, command ship and lander were at one uniform pressure.
Often, there was a putrid, burnt insulation odor when the hatch to the LM was first opened, as previous crews described, so normally time was allowed for the smell to dissipate. All of these tasks were dealt with by about 55 hours MET, much earlier than originally planned. For some reason, the LM Pilot even brought the lander’s activation check list back into the command ship for study, though activation was scheduled hours away.
“Perhaps, this would be Fred Haise’s bedtime book to read preparing himself for sleep,” Woodfill said.
But first, the crew provided a 49-minute TV broadcast showing how easily they moved about in weightlessness in the cramped spacecraft.
Then, it happened. Nine minutes later, at 55:54:56 MET, came the explosion of the oxygen tank in the Service Module. Despite ground and crew efforts to understand the problem, confusion reigned.
13 minutes after the explosion, Lovell looked out one of Odyssey’s windows and reported, “We are venting something out into space,” and quickly the crew and ground controllers knew they were losing oxygen. Without oxygen, the fuel cells that provided all the power to the CM would die. Tank 2, of course, was gone with the explosion and the plumbing on Tank 1 was severed, so the oxygen was bleeding off from that tank, as well.
At one hour, 29 seconds after the explosion, the new Capcom Jack Lousma said after instructions from Flight Director Glynn Lunney, “[The oxygen] is slowly going to zero, and we are starting to think about the LM lifeboat.” From space, astronaut Jack Swigert replied, “That’s what we have been thinking about too.”
At that point, only fifteen minutes of power remained in the Command Module.
“Fifteen minutes more and the entire assemblage might have been a corpse with no radio, no guidance, no oxygen flowing into the cabin to keep Lovell, Haise and Swigert alive,” said Woodfill. “Certainly, it was fortuitous circumstances that led to opening the LM early. Simply consider how much time it would have taken to remove both hatches, stabilize and inspect the tunnel and lander interior. Add to this the time required to power up the lander’s life support systems. As it was, they had an open pathway into a safe haven, a lifeboat, called the lunar lander, crucial to survival.”
If the LM had not been opened, the crew would have likely run out of time before the Command Module’s batteries died, which would have created several problems.
As we discussed five years ago in one of the original “13 Things” articles, all the guidance parameters which would help direct the ailing ship back to Earth were in Odyssey’s computers, and needed to be transferred over to Aquarius. Without power from the fuel cells, they kept the Odyssey alive by using the reentry batteries as an emergency measure. These batteries were designed to be used during reentry when the crew returned to Earth, and were good for limited number of hours during the time the crew would jettison the Service Module and reenter with only the tiny Command Module capsule.
“Those batteries were not ever supposed to be used until they got ready to reenter the Earth’s atmosphere,” said Woodfill. “If those batteries had been depleted, that would have been one of the worst things that could have happened. The crew worked as quickly as they could to transfer the guidance parameters, but any extra time or problem, and we could have been without those batteries. Those batteries were the only way the crew could have survived reentry. This is my take on it, but the time saved by not having to open up the Lunar Module helped those emergency batteries have just enough power in them so they could recharge them and reenter.”
By 58:40 MET, the guidance information from the Command Module computer had been transferred to the LM guidance system, the LM was fully activated and the Command and Service Module systems were turned off.
Mission Control and the crew had successfully managed the first of many “seat of the pant” procedures they would need to do in order to bring the crew of Apollo 13 back home.
To celebrate the 45th anniversary of the Apollo 13 mission, Universe Today is featuring “13 MORE Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.
Very quickly after the explosion of Oxygen Tank 2 in Apollo 13’s service module, it became apparent the Odyssey command module was dying. The fuel cells that created power for the Command Module were not working without the oxygen. But over in the Aquarius lunar lander, all the systems were working perfectly. It didn’t take long for Mission Control and the crew to realize the Lunar Module could be used as a lifeboat.
The crew quickly powered up the LM and transferred computer information from Odyssey to Aquarius. But as soon as they brought the LM communications system on line another problem developed.
The Apollo 13 crew couldn’t hear Mission Control.
The crew radioed they were getting lots of background static, and at times, they reported communications from the ground were “unreadable.”
Additionally, the Manned Space Flight Network (MSFN) tracking stations around the world were having trouble “hearing” the Apollo 13 spacecraft’s radio broadcasting the tracking data.
“Without reliable knowledge of where the vehicle was or was going might result in disaster,” said NASA engineer Jerry Woodfill.
What was going on?
The dilemma was that two radio systems were using the same frequency. One was the transmitter from the LM’s S-band antenna. The other was the broadcast from the spent third stage of the Saturn V, known as the S-IVB.
As part of a science experiment, NASA had planned for crashing Apollo 13’s S-IVB into the Moon’s surface. The Apollo 12 mission had left a seismometer on the Moon, and an impact could produce seismic waves that could be registered for hours on these seismometers. This would help scientist to better understand the structure of the Moon’s deep interior.
In Apollo 13’s nominal flight plan, the lander’s communications system would only be turned on once the crew began preparing for the lunar landing. This would have occurred well after the S-IVB had crashed into the Moon. But after the explosion, the flight plan changed dramatically.
But with both the Saturn IVB and the LM’s transmitters on the same frequency, it was like having two radio stations on the same spot on the dial. Communications systems on both ends were having trouble locking onto the correct signal, and instead were getting static or no signal at all.
The Manned Space Flight Network (MSFN) for the Apollo missions had three 85 foot (26 meter) antennas equally spaced around the world at Goldstone, California, Honeysuckle Creek, Australia and Fresnedillas (near Madrid), Spain.
According to historian Hamish Lindsay at Honeysuckle Creek, there was initial confusion. The technicians at the tracking sites immediately knew what the problem was and how they could fix it, but Mission Control wanted them to try something else.
“The Flight Controllers at Houston wanted us to move the signal from the Lunar Module across to the other side of the Saturn IVB signal to allow for expected doppler changes,” Hamish quoted Bill Wood at the Goldstone Tracking Station. ”Tom Jonas, our receiver-exciter engineer, yelled at me, ‘that’s not going to work! We will end up locking both spacecraft to one up-link and wipe out the telemetry and voice contact with the crew.’”
At that point, without the correct action, Houston lost telemetry with the Saturn IVB and voice contact with the spacecraft crew.
But luckily, the big 64 meter Mars antenna at Goldstone was already being switched over to help with the Apollo emergency and “their narrower beam width managed to discriminate between the two signals and the telemetry and voice links were restored,” said Wood.
That stabilized the communications. But then it was soon time to switch to the tracking station at Honeysuckle Creek.
There, Honeysuckle Creek Deputy Director Mike Dinn and John Mitchell, Honeysuckle Shift Supervisor were ready. Both had foreseen a potential problem with the two overlapping frequency systems and before the mission had discussed it with technicians at Goddard Spaceflight Center about what they should do if there was a communication problem of this sort.
When Dinn had been looking for emergency procedures, Mitchell had proposed the theory of getting the LM to switch off and then back on again. Although nothing had been written down, when the emergency arose, Dinn knew what they had to do.
“I advised Houston that the only way out of this mess was to ask the astronauts in the LM to turn off its signal so we could lock on to the Saturn IVB, then turn the LM back on and pull it away from the Saturn signal,” said Dinn.
It took an hour for Mission Control in Houston to agree to the procedure.
“They came back in an hour and told us to go ahead,” said Mitchell, “and Houston transmitted the instructions up to the astronauts ‘in the blind’ hoping the astronauts could hear, as we couldn’t hear them at that moment. The downlink from the spacecraft suddenly disappeared, so we knew they got the message. When we could see the Saturn IV downlink go way out to the prescribed frequency, we put the second uplink on, acquired the LM, put the sidebands on, locked up and tuned away from the Saturn IVB. Then everything worked fine.”
Dinn said they were able to “pull” the frequencies apart by tuning the station transmitters appropriately.
This action, said Jerry Woodfill, was just one more thing that saved Apollo 13.
“The booster stage’s radio was de-turned sufficiently from the frequency of the LM S-Band so that the NASA Earth Stations recognized the signal required to monitor Apollo 13’s orbit at lunar distances,” explained Woodfill. “This was altogether essential for navigating and monitoring the crucial mid-course correction burn which restored the free-return trajectory as well as the set-up of the subsequent PC+2 burn to speed the trip home needed to conserve water, oxygen and water stores to sustain the crew.”
You can hear some of the garbled communications and Mission Control issuing instructions how to potentially deal with the problem at this link from Honeysuckle Creek’s website.
As for the S-IVB science experiment, the 3rd stage crashed successfully on the Moon, providing some of the first data for understanding the Moon’s interior.
Later, on hearing that the stage had hit the Moon, Apollo 13 Commander Jim Lovell said, “Well, at least one thing worked on this mission!”
(Actually, in spite of the Apollo 13 accident, a total of four science experiments were successfully conducted on Apollo 13.)
In early 2010, NASA’s Lunar Reconnaissance Orbiter spacecraft imaged the crater left by the Apollo 13 S-IVB impact.
Thanks to space historian Colin Mackellar from the Honeysuckle Creek website, along with technician Hamish Lindsay and his excellent account of the Honeysuckle Creek Tracking station and their role in the Apollo 13 mission.
To celebrate the 45th anniversary of the Apollo 13 mission, Universe Today is featuring “13 MORE Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.
Understandably, it was chaotic in both Mission Control and in the spacecraft immediately after the oxygen tank exploded in Apollo 13’s Service Module on April 13, 1970.
No one knew what had happened.
“The Apollo 13 failure had occurred so suddenly, so completely with little warning, and affected so many spacecraft systems, that I was overwhelmed,” wrote Sy Liebergot in his book, Apollo EECOM: Journey of a Lifetime. “As I looked at my data and listened to the voice report, nothing seemed to make sense.”
But somehow, within 53 minutes of the explosion, the ship was stabilized and an emergency plan began to evolve.
“Of all of the things that rank at the top of how we got the crew home,” said astronaut Ken Mattingly, who was sidelined from the mission because he might have the measles, “was sound management and leadership.”
By chance, at the time of the explosion, two Flight Directors — Gene Kranz and Glynn Lunney — were present in Mission Control. NASA engineer Jerry Woodfill feels having these two experienced veterans together at the helm at that critical moment was one of the things that helped save the Apollo 13 crew.
“The scenario resulted from the timing,” Woodfill told Universe Today, “with the explosion occurring at 9:08 PM, and Kranz as Flight Director, but with Lunney present to assume the “hand-off” around 10:00 PM. That assured that the expertise of years of flight control leadership was conferring and assessing the situation. The presence of these colleagues, simultaneously, had to be one of the additional thirteen things that saved Apollo 13. With Lunney looking on, the transition was as seamless as a co-pilot taking the helm from a pilot of a 747 passenger jet.”
Woodfill made an additional comparison: “Having the two Flight Directors on hand at that critical moment is like having Michael Jordan and Magic Johnson on a six-man basketball squad and the referee ignoring any fouls their team might make.”
“Gene was on the team before me and he had had a long day in terms of hours. …And shortly before his shift was scheduled to end is when the “Houston, we’ve got a problem” report came in. And at first, it was not terribly clear how bad this problem was. And one of the lessons that we had learned was, “Don’t go solving something that you don’t know exists.” You’ve got to be sure … So, it was generally a go slow, let’s not jump to a conclusion, and get going down the wrong path…. We had a number of situations to deal with.”
The “not jumping to conclusions” was equally expressed by Kranz when he told his team, “Let’s solve the problem, but let’s not make it any worse by guessing.”
The presence of Kranz and Lunney, simultaneously, is especially obvious reading Gene Kranz’s book, Failure Is Not an Option.
“Kranz captures the wealth of “brain power” present at the moment of the explosion,” said Woodfill. “Besides both Kranz and Lunney, their entire teams overlapped. Yes, there were two squads on the floor competing with the dire opponents who threatened the crew’s survival.”
The crew’s survival was foremost in the minds of the Flight Directors. “We will never surrender, we will never give up a crew,” Kranz said later.
Perhaps, the most obvious evidence of how fortuitous the presence of both Kranz and Lunney was, Kranz recorded on page 316-317 of his book. The pair refuses to accept the more popular but potentially fatal decision (a direct abort) to speed the crew’s return to Earth using the damaged command ship’s engine. The direct abort would have been to jettison the lander and fire the compromised command ship’s engine to potentially quicken the return to Earth by 50 hours.
Mattingly recalled those early minutes in Mission Control after the explosion.
“The philosophy was ‘never get in the way of success,’” said Mattingly, speaking at a 2010 event at the Smithsonian Air and Space Museum. “We had choices, we debated about turning immediately around and coming home or going around the moon. In listening to all of those discussions, we never closed the door about any option of getting home. We didn’t know yet how we were going to get there, but you always make sure you don’t take a step that would jeopardize it.”
And so, with the help of their teams, the two Flight Directors quickly ran through all the options, the pros and cons, and – again – within 53 minutes after the accident they made the decision to have the crew continue their trajectory around the Moon.
Later, when Jim Lovell commented on viewing the damaged Service Module when it was jettisoned before the crew re-entered Earth’s atmosphere — “There’s one whole side of that spacecraft missing. Right by the high gain antenna, the whole panel is blown out, almost from the base to the engine,” — it was indeed an ominous look at what might have ensued using it for a quick return to Earth.
By the end of the Lunney team’s shift about ten hours after the explosion, Mission Control had put the vehicle back on an Earth return trajectory, the inertial guidance platform had been transferred to the Lunar Module, and the Lunar Module was stable and powered up for the burn planned the would occur after the crew went around the Moon. “We had a plan for what that maneuver would be, and we had a consumable profile that really left us with reasonable margins at the end,” Lunney said.
“We had many problems here – we had a variety of survival problems, we had electrical management, water management, and we had to figure out how to navigate because the stars were occluded by the debris cloud surrounding the spacecraft. Basically we had to turn a two day spacecraft into a four and a half day spacecraft with an extra crewmember to get the crew back home. We were literally working outside the design and test boundaries of the spacecraft so we had to invent everything as we went along.”
A look at the transcripts of the conversations between Flight Controllers, Flight Directors and support engineers in the Mission Evaluation Room reveals the methodical working of the problems by the various teams. Additionally, you can see how seamlessly the teams worked together, and when one shift handed off to another, everything was communicated.
Lunney explains:
“The other thing I would say about it is, and we talked about Flight Directors and teams, equally important was the fact that, during those flights, we had this Operations team that you have seen in the Control Center in the back rooms around it and we sort of had our own way of doing things in our own team, and we were fully prepared to decide whatever had to be decided. But in addition to that, we had the engineering design teams that would follow the flight along and look at various problems that occurred and put their own disposition on them. …That was part of this network of support. People had their certain jobs to do. They knew what it was. They knew how they fit in. And they were anticipating and off doing it.”
Without the leadership of the Flight Directors, keeping the teams focused and on-task, the outcome of the Apollo 13 mission may have been much different.
“It is the experience of these two, Kranz and Lunney, working together which likely saved the crew from what might have been certain death,” said Woodfill.
In our original series 5 years ago on the “13 Things That Saved Apollo 13,” the first item we discussed was the timing of the explosion. As NASA engineer Jerry Woodfill told us, if the tank was going to rupture and the crew was going to survive the ordeal, the explosion couldn’t have happened at a better time.
An explosion earlier in the mission (assuming it would have occurred after Apollo 13 left Earth orbit) would have meant the distance and time to get back to Earth would have been so great that there wouldn’t have been sufficient power, water and oxygen for the crew to survive. An explosion later, perhaps after astronauts Jim Lovell and Fred Haise had already descended to the lunar surface, and all three crew members wouldn’t have been able to use the lunar lander as a lifeboat. Additionally, the two spacecraft likely couldn’t have docked back together, and without the descent stage’s consumables left on the Moon (batteries, oxygen, etc.) that would have been a fruitless endeavor.
Now, for our first article in our subsequent series “13 MORE Things That Saved Apollo 13,” we’re going to revisit that timing, but look more in detail as to WHY the explosion happened when it did, and how it affected the rescue of the crew. The answer lies with the failure of a pressure sensor in Oxygen Tank 2, an issue unrelated to the uninsulated wires in the tank that caused the explosion.
Most who are familiar with the story of Apollo 13 are acquainted with the cause of the explosion, later determined by an accident investigation committee led by Edgar Cortright, Director of the Langley Research Center.
The tank had been dropped five years before the flight of Apollo 13, and no one realized the vent tube on the oxygen tank was jarred out of alignment. After a Count Down Demonstration Test (CDDT) conducted on March 16, 1970 when all systems were tested while the Apollo 13 spacecraft sat atop the Saturn V rocket on the launch-pad, the cold liquid oxygen would not empty out of Oxygen Tank 2 through that flawed vent pipe.
The normal approach was to use gaseous oxygen to push the liquid oxygen out of the tank through the vent pipe. Since that wasn’t working, technicians decided the easiest and quickest way to empty the liquid oxygen would be to boil it off using the heaters in the tank.
“In each oxygen tank were heaters and a paddle wheel fan,” Woodfill explained. “The heater and fan (stirrer) device encouraged a portion of the cold liquid 02 to turn into a higher pressure 02 gas and flow into the fuel cells. A fan also known as the cryo-stirrer was powered each time the heater was powered. The fan served to stir the liquid 02 to assure it was uniformly consistent in density.”
To protect the heater from being overly hot, a switch-like device called a relay turned off heater power anytime the temperature exceeded 80 degrees F. Also, there was a temperature gauge which technicians on the ground could monitor if temperature exceeded 80 degree F.
The original Apollo spacecraft worked on 28 volts of electricity, but after the 1967 fire on the Launchpad for Apollo 1, the Apollo spacecraft’s electrical systems had been modified to handle 65 volts from the external ground test equipment. Unfortunately Beech, the tank’s manufacturer failed to change out this tank, and the heater safety switch was still set for 28 volt operation.
“When the heater was powered up to vent the tank, the higher voltage “fused” the relay contacts so that the switch could not turn off power when the temperature of the tank exceeded 80 degrees F (27 C),” said Woodfill.
Additionally, the temperature gauge on the ground test panel only went to 88 degrees F (29.5 C), so no one was aware of this excessive heat.
“As a result,” said Woodfill, “the heater and the wires which powered it reached estimated temperatures of around 1000 degrees F. (538°C), hot enough to melt the Teflon insulation on the heater wires and leave portions of them bare. Bare wires meant the potential for a short-circuit and an explosion since these wires were immersed in the liquid oxygen.”
Because the tank had been dropped, and because its heater design had not been updated for 65 volt operation, the tank was a virtual bomb, Woodfill said. Anytime power was applied to those heaters to stir the tank’s liquid oxygen, an explosion was possible.
At 55:54:53 Mission Elapsed Time (MET), the crew was asked to conduct a stir of the oxygen tanks. It was then that the damaged wires in Oxygen Tank 2 shorted out and the insulation ignited. The resulting fire rapidly increased pressure beyond its nominal 1,000 psi (7 MPa) limit and either the tank or the tank dome failed.
But back to the quantity sensor on Oxygen Tank 2. For a reason yet to be understood, during the early part of the Apollo 13 flight, the sensor failed. Prior to launch, that Tank 2 quantity sensor was being monitored by the onboard telemetry system, and it apparently worked perfectly.
“The failure of that probe in space is, perhaps, the most important reason Apollo 13’s crew lived,” said Woodfill.
Here’s the explanation of why Woodfill makes that claim.
Woodfill’s research of Apollo 13 indicated that standard operating procedure (SOP) had Mission Control request a stirring of the cryos approximately every 24 hours. For the Apollo 13 mission, the first stir came about 24 hours into the mission (23:20:23 MET). Ordinarily, the next cryo stir would not be called for until 24 hours later. The heater-cryo stir procedure was done to assure accuracy of the quantity gauge and proper operation of the system through the elimination of O2 stratification. The sensor read more accurately because the stir made the liquid oxygen more uniform and less stratified. After the first stir, 87 % remaining oxygen quantity was indicated, a bit ahead of expectations. The next stir came about a day later, about 46:40 MET.
At the time of this second heater-cryo-stir, Oxygen Tank 2’s quantity sensor failed. Post mission analysis by the investigation committee indicated the failure was not related to the bare heater wires.
The loss of ability to monitor Oxygen Tank 2’s quantity caused mission control to radio to the crew: “(Because the quantity sensor failed,) we’re going to be requesting you stir the cryos every six hours to help gage how much 02 is in tank 2.”
However, Mission Control chose to perform some analysis of the situation in Tank 2 by calling for another stir, not at 53 hours MET but at 47:54:50 MET and still another at 51:07:41 . Because the other oxygen tank, Tank 1, indicated a low pressure, both tanks were stirred at 55:53.
“Count the number of stirs since launch,” Woodfill said. “1. at 23:20:23, 2. at 46:40, 3. at 47:54:50, 4. at 51:07:44 and 5. at 55:53. There were five applications of current to those bare heater wires. The last three occurred over a period of only 8 hours rather than 72 hours. Had it not been for the non-threatening failure of Tank 2’s quantity probe and the low pressure in O2 Tank 1, this would not have been the case.”
Woodfill explained that anyone who has analyzed hardware failures understands that the more frequent and shorter the period between operations of a flawed component hastens ultimate failure. NASA performs stress testing on hundreds of electrical systems using this approach. More frequent power-ups at shorter intervals encourages flawed systems to fail sooner.
The short circuit in Oxygen Tank 2 after the fifth heater-cryo-stir resulted in the explosion of Apollo 13’s Oxygen Tank 2. Had the normal sequence of stirs been performed at 24 hour intervals, and the failure came after the fifth stirring, the explosion would have occurred after the lunar module, the life boat, was no longer available.
“I contend that the quantity sensor malfunction was fortuitous and assured the lander would be present and fully fueled at the time of the disaster,” Woodfill said.
5 heater actuations at 24 hours periods amounts to a MET of 120 hours.
“The lunar lander would have departed for the Moon at 103.5 hours into the mission,” Woodfill said. “At 120 hours into the mission, the crew of Lovell and Haise would have been awakened from their sleep period, having completed their first moon walk eight hours before. They would receive an urgent call from Jack Swigert and/or Mission Control that something was amiss with the Mother ship orbiting the Moon.”
Furthermore, Woodfill surmised, analysis of Swigert’s ship’s problems would likely be clouded by the absence of his two crewmates on the lunar surface. Added problems for Mission Control would have been the interruption of communications each time the command ship went behind the Moon, interrupting the telemetry so crucial to analyzing the failure. When it became evident, the cryogenic system would no longer produce oxygen, water, and electrical power, those command module emergency batteries would have been activated. Likely, Mission Control would have ordered an abort of the lunar lander earlier, but, of course, that would have been futile. Had the tiny lander’s ascent stage rendezvoused and docked with the depleted CM, all the life supporting descent stage consumables would remain on the Moon.
“The nightmare would have the Apollo 13 crew saying their last farewells to their families and friends,” said Woodfill. “One can only speculate how the end might have come.”
And there likely would not have been Apollo 14, 15, 16 and 17 — at least not for a very long time.
Another aspect of the timing of the explosion that Woodfill has considered is, why didn’t the tank explode on the Launchpad?
Following the March 16 CDDT, no additional “power-up” or tests were planned. However, it is not uncommon for pre-launch re-verification to be performed.
“One such re-check might easily have been these heater circuits since they had been used in a non-standard way to empty the oxygen from the cryo tanks after the Countdown Demonstration Test (CDDT) weeks earlier,” Woodfill said. “Such re-do’s often occur for myriad reasons. For Apollo 13, despite the compromised system, none occurred until the craft was safely on its way to the Moon.”
However, such a routine re-test involving cryo stirring would have unknowingly jeopardized the launch vehicle, support persons, or astronaut crew.
Or, if the quantity sensor had failed on the ground, likely the same kind of trouble shooting that was done by Mission Control and the Apollo 13 crew, would have been performed by the KSC ground team.
Had the sensor failed at that time, a series of heater actuations/stirrings would have been executed to trouble-shoot the device.
“Of course, the result would have been the same kind of explosion nearly 55 hours 55 minutes after launch,” Woodfill said. “On the ground, the Apollo 13 explosion could have taken the lives of Lovell and crew if trouble-shooting had been done while the crew awaited launch.”
If the trouble-shooting had been done earlier, with several heater actuations/stirrings during the days before the launch, Woodfill said, “a terrible loss of life would have ensued with, potentially, scores of dedicated Kennedy Space Center aerospace workers bravely attempting to fix the problem. And the towering thirty-six story Saturn 5 would have collapsed earthward in a ball of fire reminiscent of that December 1957 demise of America’s Vanguard rocket.”
“Yes, the fact that the Oxygen Tank 2 quantity sensor did not fail on the launch pad, but failed early in the flight was one of the additional things that saved Apollo 13.”
“Things had gone real well up to at that point of 55 hours, 54 minutes and 53 seconds (mission elapsed time),” said Apollo 13 astronaut Fred Haise as he recounted the evening of April 13, 1970, the night the Apollo 13’s command module’s oxygen tank exploded, crippling the spacecraft and endangering the three astronauts on board.
“Mission Control had asked for a cryo-stir in the oxygen tank …and Jack threw the switches,” Haise continued. “There was a very loud bang that echoed through the metal hull, and I could hear and see metal popping in the tunnel [between the command module and the lunar lander]… There was a lot of confusion initially because the array of warning lights that were on didn’t resemble anything we have ever thought would represent a credible failure. It wasn’t like anything we were exposed to in the simulations.”
What followed was a four-day ordeal as Haise, Jim Lovell and Jack Swigert struggled to get back to Earth, as thousands of people back on Earth worked around the clock to ensure the astronauts’ safe return.
In 2010, Universe Today also commemorated the Apollo 13 anniversary with a series of articles titled “13 Things That Saved Apollo 13.” We looked at 13 different items and events that helped turn the failure into success, overcoming the odds to get the crew back home. We interviewed NASA engineer Jerry Woodfill, who helped design the alarm and warning light system for the Apollo program, which Haise described above.
Now, five years later on the 45th anniversary of Apollo 13, Woodfill returns with “13 MORE Things That Saved Apollo 13.” Over the next few weeks, we’ll look at 13 additional things that helped bring the crew home safely.
Woodfill has worked for NASA for almost 50 years as an engineer, and is one of 27 people still remaining at Johnson Space Center who were also there for the Apollo program. In the early days of Apollo, Woodfill was the project engineer for the spacecraft switches, gauges, and display and control panels, including the command ship’s warning system.
On that night in April 1970 when the oxygen tank in Apollo 13’s command module exploded, 27-year-old Woodfill sat at his console in the Mission Evaluation Room (MER) at Johnson Space Center, monitoring the caution and warning system.
“It was 9:08 pm, and I looked at the console because it flickered a few times and then I saw a master alarm come on,” Woodfill said. “Initially I thought something was wrong with the alarm system or the instrumentation, but then I heard Jack Swigert in my headset: “Houston, we’ve had a problem,” and then a few moments later, Jim Lovell said the same thing.”
Listen to the audio of communications between the crew and Mission Control at the time of the explosion:
Located in an auxiliary building, the MER housed the engineers who were experts in the spacecrafts’ systems. Should an inexplicable glitch occur, the MER team could be consulted. And when alarms starting ringing, the MER team WAS consulted.
The ebullient and endearing Woodfill brings a wealth of knowledge — as well as his love for public outreach for NASA — to everything he does. But also, for the past 45 years he has studied the Apollo 13 mission in intricate detail, examining all the various facets of the rescue by going through flight transcripts, debriefs, and other documents, plus he’s talked to many other people who worked during the mission. Fascinated by the turn of events and individuals involved who turned failure into success, Woodfill has come up with 13 MORE things that saved Apollo 13, in addition to the original 13 he shared with us in 2010.
Woodfill tends to downplay both his role in Apollo 13 and the significance of the MER.
“In the MER, I was never involved or central to the main events which rescued Apollo 13,” Woodfill told Universe Today. “Our group was available for mission support. We weren’t flight controllers, but we were experts. For other missions that were routine we didn’t play that big of a role, but for the Apollo 13 mission, we did play a role.”
But Apollo Flight Director Gene Kranz, also speaking at the 2010 event at the Smithsonian Air and Space Museum, has never forgotten the important role the MER team played.
“The thing that was almost miraculous here [for the rescue], was I think to a great extent, the young controllers, particularly the systems guys who basically invented the discipline of what we now call systems engineering,” Kranz said. “The way these guys all learned their business, … got to know the designs, the people and the spacecraft … and they had to translate all that into useful materials that they could use on console in real time.”
Join Universe Today in celebrating the 45th anniversary of Apollo 13 with Woodfill’s insights as we discuss each of the 13 additional turning points in the mission. And here’s a look back at the original “13 Things That Saved Apollo 13:
Every year since 1970, astronomers, geologists, geophysicists, and a host of other specialists have come together to participate in the Lunar and Planetary Science Conference (LPCS). Jointly sponsored by the Lunar and Planetary Institute (LPI) and NASA’s Johnson Space Center (JSC), this annual event is a chance for scientists from all around the world to share and present the latest planetary research concerning Earth’s only moon.
This year, one of the biggest attention-grabbers was the findings presented on Tuesday, March 17th by a team of students from Purdue University. Led by a graduate student from the university’s Department of Earth, Atmospheric and Planetary Sciences, the study they shared indicates that there may be stable lava tubes on the moon, ones large enough to house entire cities.
In addition to being a target for future geological and geophysical studies, the existence of these tubes could also be a boon for future human space exploration. Basically, they argued, such large, stable underground tunnels could provide a home for human settlements, shielding them from harmful cosmic radiation and extremes in temperature.
Lava tubes are natural conduits formed by flowing lava that is moving beneath the surface as a result of a volcanic eruption. As the lava moves, the outer edges of it cools, forming a hardened, channel-like crust which is left behind once the lava flow stops. For some time, Lunar scientists have been speculating as to whether or not lava flows happen on the Moon, as evidenced by the presence of sinuous rilles on the surface.
Sinuous rilles are narrow depressions in the lunar surface that resemble channels, and have a curved paths that meanders across the landscape like a river valley. It is currently believed that these rilles are the remains of collapsed lava tubes or extinct lava flows, which is backed up by the fact they usually begin at the site of an extinct volcano.
Those that have been observed on the Moon in the past range in size of up to 10 kilometers in width and hundreds of kilometers in length. At that size, the existence of a stable tube – i.e. one which had not collapsed to form a sinuous rille – would be large enough to accommodate a major city.
For the sake of their study, the Purdue team explored whether lava tubes of the same scale could exist underground. What they found was that the stability of a lava tube depended on a number of variables- including width, roof thickness and the stress state of the cooled lava. he researchers also modeled lava tubes with walls created by lava placed in one thick layer and with lava placed in many thin layers.
David Blair, a graduate student in Purdue’s Department of Earth, Atmospheric and Planetary Sciences, led the study that examined whether empty lava tubes more than 1 kilometer wide could remain structurally stable on the moon.
“Our work is somewhat unique in that we’ve combined the talents of people from various Departments at Purdue,” Blair told Universe Today via email. “With guidance from Prof. Bobet (a civil engineering professor) we’ve been able to incorporate a modern understanding of rock mechanics into our computer models of lava tubes to see how they might actually fail and break under lunar gravity.”
For the sake of their research, the team constructed a number of models of lava tubes of different sizes and with different roof thicknesses to test for stability. This consisted of them checking each model to see if it predicted failure anywhere in the lava tube’s roof.
“What we found was surprising,” Blair continued, “in that much larger lava tubes are theoretically possible than what was previously thought. Even with a roof only a few meters thick, lava tubes a kilometer wide may be able to stay standing. The reason why, though, is a little less surprising. The last work we could find on the subject is from theApolloera, and used a much simpler approximation of lava tube shape – a flat beam for a roof.
The study he refers to, “On the origin of lunar sinuous rilles“, was published in 1969 in the journal Modern Geology. In it, professors Greeley, Oberbeck and Quaide advanced the argument that sinuous rilles formation was tied to the collapse of lava flow tubes, and that stable ones might still exist. Calculating for a flat-beam roof, their work found a maximum lava tube size of just under 400 m.
“Our models use a geometry more similar to what’s seen in lava tubes on Earth,” Blair said, “a sort of half-elliptical shape with an arched roof. The fact that an arched roof lets a larger lava tube stay standing makes sense: humans have known since antiquity that arched roofs allow tunnels or bridges to stay standing with wider spans.”
The Purdue study also builds on previous studies conducted by JAXA and NASA where images of “skylights” on the Moon – i.e. holes in the lunar surface – confirmed the presence of caverns at least a few tens of meters across. The data from NASA’s lunar Gravity Recovery And Interior Laboratory (GRAIL) – which showed big variations in the thickness of the Moon’s crust is still being interpreted, but could also be an indication of large subsurface recesses.
As a result, Blair is confident that their work opens up new and feasible explanations for many different types of observations that have been made before. Previously, it was unfathomable that large, stable caverns could exist on the Moon. But thanks to his team’s theoretical study, it is now known that under the proper conditions, it is least possible.
Another exciting aspect that this work is the implications it offers for future exploration and even colonization on the Moon. Already, the issue of protection against radiation is a big one. Given that the Moon has no atmosphere, colonists and agricultural operations will have no natural shielding from cosmic rays.
“Geologically stable lava tubes would absolutely be a boon to human space exploration,” Blair commented. “A cavern like that could be a really ideal place for building a lunar base, and generally for supporting a sustained human presence on the Moon. By going below the surface even a few meters, you suddenly mitigate a lot of the problems with trying to inhabit the lunar surface.”
Basically, in addition to protecting against radiation, a subsurface base would sidestep the problems of micrometeorites and the extreme changes in temperature that are common on the lunar surface. What’s more, stable, subsurface lava tubes could also make the task of pressurizing a base for human habitation easier.
“People have studied and talked about all of these things before,” Blair added, “but our work shows that those kinds of opportunities could potentially exist – now we just have to find them. Humans have been living in caves since the beginning, and it might make sense on the Moon, too!”
In addition to Melosh, Blair and Bobet, team members include Loic Chappaz and Rohan Sood, graduate students in the School of Aeronautics and Astronautics; Kathleen Howell, Purdue’s Hsu Lo Professor of Aeronautical and Astronautical Engineering; Andy M. Freed, an associate professor of earth, atmospheric and planetary sciences; and Colleen Milbury, a postdoctoral research associate in the Department of Earth, Atmospheric and Planetary Sciences.
In Kubrick’s and Clark’s 2001 Space Odyssey, there was no question of “Boots or Bots”[ref]. The monolith had been left for humanity as a mileage and direction marker on Route 66 to the stars. So we went to Jupiter and Dave Bowman overcame a sentient machine, shut it down cold and went forth to discover the greatest story yet to be told.
Now Elon Musk, born three years after the great science fiction movie and one year before the last Apollo mission to the Moon has set his goals, is achieving milestones to lift humans beyond low-Earth orbit, beyond the bonds of Earth’s gravity and take us to the first stop in the final frontier – Mars – the destination of the SpaceX odyssey.
Ask him what’s next and nowhere on his bucket list does he have Disneyland or Disney World. You will find Falcon 9R, Falcon Heavy, Dragon Crew, Raptor Engine and Mars Colonization Transporter (MCT).
At the top of his working list is the continued clean launch record of the Falcon 9 and beside that must-have is the milestone of a soft landing of a Falcon 9 core. To reach this milestone, Elon Musk has an impressive array of successes and also failures – necessary, to-be-expected and effectively of equal value. His plans for tomorrow are keeping us on the edge of our seats.
CRS-5, the Cargo Resupply mission number 5, was an unadulterated success and to make it even better, Elon’s crew took another step towards the first soft landing of a Falcon core, even though it wasn’t entirely successful. Elon explained that they ran out of hydaulic fluid. Additionally, there is a slew of telemetry that his engineers are analyzing to optimize the control software. Could it have been just a shortage of fluid? Yes, it’s possible they could extrapolate the performance that was cut short and recognize the landing Musk and crew dreamed of.
The addition of the new grid fins to improve control both assured the observed level of success and also assured failure. Anytime one adds something unproven to a test vehicle, the risk of failure is raised. This was a fantastic failure that provided a treasure trove of new telemetry and the possibilities to optimize software. More hydraulic fluid is a must but improvements to SpaceX software is what will bring a repeatable string of Falcon core soft landings.
“Failure is not an option,” are the famous words spoken by Eugene Kranz as he’s depicted in the movie Apollo 13. Failure to Elon Musk and to all of us is an essential part of living. However, from Newton to Einstein to Hawking, the equations to describe and define how the Universe functions cannot show failure otherwise they are imperfect and must be replaced. Every moment of a human life is an intertwined array of success and failure. Referring only to the final frontier, in the worse cases, teams fall out of balance and ships fall out of the sky. Just one individual can make a difference between his or a team’s success. Failure, trial and error is a part of Elon’s and SpaceX’s success.
He doesn’t quote or refer to Steve Jobs but Elon Musk is his American successor. From Hyperloops, to the next generation of Tesla electric vehicles, Musk is wasting no time unloading ideas and making his dreams reality. Achieving his goals, making milestones depends also on bottom line – price and performance into profits. The Falcon rockets are under-cutting ULA EELVs (Atlas & Delta) by more than half in price per pound of payload and even more with future reuse. With Falcon Heavy he will also stake claim to the most powerful American-made rocket.
Musk’s success will depend on demand for his product. News in the last week of his investments in worldwide space-based internet service also shows his intent to promote products that will utilize his low-cost launch solutions. The next generation of space industry could falter without investors and from the likes of Musk, re-investing to build demand for launch and sustaining young companies through their start-up phases. Build it and they will come but take for granted, not recognize the fragility of the industry, is at your own peril.
So what is next in the SpaceX Odyssey? Elon’s sights remain firmly on the Falcon 9R (Reuse) and the Falcon Heavy. Nothing revolutionary on first appearance, the Falcon Heavy will look like a Delta IV Heavy on steroids. Price and performance will determine its success – there is no comparison. It is unclear what will become of the Delta IV Heavy once the Falcon Heavy is ready for service. There may be configurations of the Delta IV with an upper stage that SpaceX cannot match for a time but either way, the US government is likely to effectively provide welfare for the Delta and even Atlas vehicles until ULA (Lockheed Martin and Boeing’s developed corporation) can develop a competitive solution. The only advantage remaining for ULA is that Falcon Heavy hasn’t launched yet. Falcon Heavy, based on Falcon 9, does carry a likelihood of success based on Falcon 9’s 13 of 13 successful launches over the last 5 years. Delta IV Heavy has had 7 of 8 successful launches over a span of 11 years.
The convergence of space science and technology and science fiction in the form of Musk’s visions for SpaceX is linked to the NASA legacy beginning with NASA in 1958, accelerated by JFK in 1962 and landing upon the Moon in 1969. The legacy spans backward in time to Konstantin Tsiolkovsky, Robert Goddard, Werner Von Braun and countless engineers and forward through the Space Shuttle and Space Station era.
The legacy of Shuttle is that NASA remained Earth-bound for 30-plus years during a time that Elon Musk grew up in South Africa and Canada and finally brought his visions to the United States. With a more daring path by NASA, the story to tell today would have been Moon bases or Mars missions completed in the 1990s and commercial space development that might have outpaced or pale in comparison to today’s. Whether Musk would be present in commercial space under this alternate reality is very uncertain. But Shuttle retirement, under-funding its successor, the Ares I & V and Orion, cancelling the whole Constellation program, then creating Commercial Crew program, led to SpaceX winning a contract and accelerated development of Falcon 9 and the Dragon capsule.
SpaceX is not meant to just make widgets and profit. Mars is the objective and whether by SpaceX or otherwise, it is the first stop in humankind’s journey into the final frontier. Mars is why Musk developed SpaceX. To that end, the first focal point for SpaceX has been the development of the Merlin engine.
Now, SpaceX’s plans for Mars are focusing on a new engine – Raptor and not a Merlin 2 – which will operate on liquified methane and liquid oxygen. The advantage of methane is its cleaner combustion leaving less exhaust deposits within the reusable engines. Furthermore, the Raptor will spearhead development of an engine that will land on Mar and be refueled with Methane produced from Martian natural resources.
The Raptor remains a few years off and the design is changing. A test stand has been developed for testing Raptor engine components at NASA’s Stennis Space Center. In a January Reddit chat session[ref] with enthusiasts, Elon replied that rather than being a Saturn F-1 class engine, that is, thrust of about 1.5 million lbf (foot-lbs force), his engineers are dialing down the size to optimize performance and reliability. Musk stated that plans call for Raptor engines to produce 500,000 lbf (2.2 million newtons) of thrust. While smaller, this represents a future engine that is 3 times as powerful as the present Merlin engine (700k newtons/157 klbf). It is 1/3rd the power of an F-1. Musk and company will continue to cluster engines to make big rockets.
To achieve their ultimate goal – Mars colonization, SpaceX will require a big rocket. Elon Musk has repeatedly stated that a delivery of 100 colonists per trip is the present vision. The vision calls for the Mars Colonization Transporter (MCT). This spaceship has no publicly shared SpaceX concept illustrations as yet but more information is planned soon. A few enthusiasts on the web have shared their visions of MCT. What we can imagine is that MCT will become a interplanetary ferry.
The large vehicle is likely to be constructed in low-Earth orbit and remain in space, ferrying colonists between Earth orbit and Mars orbit. Raptor methane/LOX engines will drive it to Mars and back. Possibly, aerobraking will be employed at both ends to reduce costs. Raptor engines will be used to lift a score of passengers at a time and fill the living quarters of the waiting MCT vehicle. Once orbiting Mars, how does one deliver 100 colonists to the surface? With atmospheric pressure at its surface equivalent to Earth’s at 100,000 feet, Mars does not provide an Earth-like aerodynamics to land a large vehicle.
In 1952, Werner Von Braun in his book “Mars Projekt” envisioned an armada of ships, each depending on launch vehicles much larger than the Saturn V he designed a decade later. Like the invading Martians of War of the Worlds, the armada would rather converge on Mars and deploy dozens of winged landing vehicles that would use selected flat Martian plain to skid with passengers to a safe landing. For now, Elon and SpaceX illustrate the landing of Dragon capsules on Mars but it will clearly require a much larger lander. Perhaps, it will use future Raptors to land softly or possibly employ winged landers such as Von Braun’s after robotic Earth-movers on Mars have constructed ten or twenty mile long runways.
We wait and see what is next for Elon Musk’s SpaceX vision, his SpaceX Odyssey. For Elon Musk and his crew, there are no “wives” – Penelope and families awaiting their arrival on Mars. Their mission is more than a five year journey such as Star Trek. The trip to Mars will take the common 7 months of a Hohmann transfer orbit but the mission is really measured in decades. In the short-term, Falcon 9 is poised to launch again in early February and will again attempt a soft landing on a barge at sea. And later, hopefully, in 2015, the Falcon Heavy will make its maiden flight from Cape Canaveral’s rebuilt launch pad 39A where the Saturn V lifted Apollo 11 to the Moon and the first, last and many Space Shuttles were launched.
Happy Birthday to my sister Sylvia who brought home posters, literature and interest from North American-Rockwell in Downey during the Apollo era and sparked my interest.
Orion’s inaugural launch on Dec. 5, 2014 atop United Launch Alliance Delta 4 Heavy rocket at Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station, Florida at 7:05 a.m. Credit: Alex Polimeni/Zero-G News/AmericaSpace
Expanded with a growing gallery![/caption]
KENNEDY SPACE CENTER, FL – After four decades of waiting, the dawn of a new era in space exploration finally began with the dawn liftoff of NASA’s first Orion spacecraft on Friday, Dec. 5, 2014.
The picture perfect liftoff of Orion on its inaugural unmanned test flight relit the path to send humans beyond low Earth orbit for the first time since the launch of Apollo 17 on NASA’s final moon landing mission on Dec. 7, 1972.
Orion soared to space atop a United Launch Alliance Delta IV Heavy rocket at 7:05 a.m. EST from Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.
Enjoy the spectacular launch photo gallery from my fellow space journalists and photographers captured from various up close locations ringing the Delta launch complex.
Tens of thousands of spectators descended upon the Kennedy Space Center to be an eyewitness to history and the new space era – and they were universally thrilled.
Orion is the first human rated spacecraft to fly beyond low Earth orbit since Apollo 17 and was built by prime contractor Lockheed Martin.
The EFT-1 mission was a complete success.
The Orion program began about a decade ago.
America’s astronauts flying aboard Orion will venture farther into deep space than ever before – beyond the Moon to Asteroids, Mars and other destinations in our Solar System starting around 2020 or 2021 on Orion’s first crewed flight atop NASA’s new monster rocket – the SLS – concurrently under development.
Watch for Ken’s ongoing Orion coverage from onsite at the Kennedy Space Center about the historic launch on Dec. 5.
Stay tuned here for Ken’s continuing Orion and Earth and planetary science and human spaceflight news.
KENNEDY SPACE CENTER, FL – This week’s appearance of the Moon over the Kennedy Space Center marks the perfect backdrop heralding the start of NASA’s determined push to send Humans to Mars by the 2030s via the agency’s new Orion crew capsule set to soar to space on its maiden test flight in less than two days.
Orion is the first human rated vehicle that can carry astronauts beyond low Earth orbit on voyages to deep space in more than 40 years.
Top managers from NASA, United Launch Alliance (ULA), and Lockheed Martin met on Tuesday, Dec. 2, and gave the “GO” to proceed toward launch after a thorough review of all systems related to the Orion capsule, rocket, and ground operation systems at the launch pad at the Launch Readiness Review (LRR), said Mark Geyer at a NASA media briefing on Dec. 2.
Orion is slated to lift off on a United Launch Alliance Delta IV Heavy rocket on its inaugural test flight to space on the uncrewed Exploration Flight Test-1 (EFT-1) mission at 7:05 a.m. EST on December 4, 2014, from Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.
America’s astronauts flying aboard Orion will venture farther into deep space than ever before – beyond the Moon to Asteroids, Mars, and other destinations in our Solar System starting around 2020 or 2021 on Orion’s first crewed flight atop NASA’s new monster rocket – the SLS – concurrently under development.
The current weather forecast states the launch is 60 percent “GO” for favorable weather condition at the scheduled liftoff time of at 7:05 a.m. on Dec. 4, 2014.
The launch window extends for 2 hours and 39 minutes.
The two-orbit, four and a half hour Orion EFT-1 flight around Earth will lift the Orion spacecraft and its attached second stage to an orbital altitude of 3,600 miles, about 15 times higher than the International Space Station (ISS) – and farther than any human spacecraft has journeyed in 40 years.
EFT-1 will test the rocket, second stage, and jettison mechanisms, as well as avionics, attitude control, computers, and electronic systems inside the Orion spacecraft.
Then the spacecraft will carry out a high speed re-entry through the atmosphere at speeds approaching 20,000 mph and scorching temperatures near 4,000 degrees Fahrenheit to test the heat shield, before splashing down for a parachute assisted landing in the Pacific Ocean.
NASA TV will provide several hours of live Orion EFT-1 launch coverage with the new countdown clock – starting at 4:30 a.m. on Dec. 4.
Watch for Ken’s ongoing Orion coverage and he’ll be onsite at KSC in the days leading up to the historic launch on Dec. 4.
Stay tuned here for Ken’s continuing Orion and Earth and planetary science and human spaceflight news.
Ken Kremer
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Learn more about Orion, SpaceX, Antares, NASA missions, and more at Ken’s upcoming outreach events:
Dec 1-5: “Orion EFT-1, SpaceX CRS-5, Antares Orb-3 launch, Curiosity Explores Mars,” Kennedy Space Center Quality Inn, Titusville, FL, evenings