Fleet of Solar Sail Spacecraft Envisioned for Future Data Gathering Missions


Future missions to explore the outer planets could employ fleets of ‘data-clippers’, maneuverable spacecraft equipped with solar sails, to ship vast quantities of scientific data back to Earth. According to Joel Poncy of satellite developer Thales Alenia Space, the technology could be ready in time to support upcoming missions to the moons of Jupiter and Saturn.

“Space-rated flash memories will soon be able to store the huge quantities of data needed for the global mapping of planetary bodies in high resolution.” said Poncy. “But a full high-res map of, say, Europa or Titan, would take several decades to download from a traditional orbiter, even using very large antennae. Downloading data is the major design driver for interplanetary missions. We think that data clippers would be a very efficient way of overcoming this bottleneck.”

Poncy and his team have carried out a preliminary assessment for a data clipper mission. Their concept is for a clipper to fly close to a planetary orbiter, upload its data and fly by Earth, at which point terabytes of data could be downloaded to the ground station. A fleet of data clippers cruising around the Solar System could provide support for an entire suite of planetary missions.

“We have looked at the challenges of a data clipper mission and we think that it could be ready for a launch in the late 2020s. This means that the technology should be included now in the roadmap for future missions,” said Poncy.

Spurred by the success of the Japanese Space Agency’s current solar sail mission, IKAROS, Poncy’s team have assessed the communications systems and tracking devices that a data clipper would need, as well as the flyby conditions and pointing accuracy required for the massive data transfers. Recent advances in technology mean that spacecraft propelled by solar sails, which use radiation pressure from photons emitted by the Sun, or electric sails, which harness the momentum of the solar wind, can now be envisaged for mid-term missions.

“Using the Sun as a propulsion source has the considerable advantage of requiring no propellant on board. As long as the hardware doesn’t age too much and the spacecraft is maneuverable, the duration of the mission can be very long. The use of data clippers could lead to a valuable downsizing of exploration missions and lower ground operation costs – combined with a huge science return. The orbiting spacecraft would still download some samples of their data directly to Earth to enable real-time discoveries and interactive mission operations. But the bulk of the data is less urgent and is often processed by scientists much later. Data clippers could provide an economy delivery service from the outer Solar System, over and over again,” said Poncy.

Poncy will be presenting an assessment of data clippers at the European Planetary Science Congress in Rome on Monday September, 20, 2010.

Source: European Planetary Science Congress

Needed: Plutonium-238

Space Probes


Sometimes people ask what they, as a regular citizen can do to help NASA. Emily Lakdawalla at the Planetary Society Blog posted this today, and this is definitely something to write to members of Congress about. NASA is running out of plutonium-238, which is used to power deep space probes, but it’s unclear whether Congress will provide the $30 million that has been requested for the Department of Energy to start new production.

Plutonium-238 has powered dozens of spacecraft, including the Voyager probes, the Galileo mission to Jupiter, and the Cassini spacecraft that is currently sending back such amazing images of Saturn’s rings and moons. Because of spacecraft powered by plutonium-238, we now know — among other things — that there are volcanoes on Jupiter’s moon Io and geysers on Saturn’s moon Enceladus.

Plutonium-238 was a by-product of Cold War activities, and the U.S. has not made any new supplies since the 1980s. Since 1993, all of the plutonium-238 the US has used in space probes has been purchased from Russia. It’s not the same as plutonium-239, which is used in nuclear weapons; a small marshmallow-sized pellet of plutonium-238 gives off heat, which is used to power spacecraft that can’t rely solely on energy from solar panels. Without this energy source, future missions could be canceled.

Emily posted this letter from the chair of the Division of Planetary Sciences of the American Astronomical Society Candy Hansen:

Members of the DPS Federal Relations Subcommittee and the DPS committee carried out our annual “Hill” visits May 13 to key members of Congress. We had two messages – restart domestic production of plutonium-238, and our concerns about R&A carry-over language. With regards to the production of plutonium-238, we are not out of the woods. We still need to convince the members of the Appropriations Subcommittee on Energy and Water that this is a critical need right now – that NASA is already curtailing missions to the outer solar system, and anywhere else plutonium-238 is required (the New Frontiers 3 Announcement of Opportunity ruled out missions which require plutonium-238).

In particular we need constituents of the following states to write letters:

Senate Appropriations Committee Subcommittee on Energy and Water Development:
Dorgan (ND)
Byrd (WV)
Feinstein (CA)
Bennett (UT)
Hutchison (TX)
Murray (WA)
Bond (MO)
Alexander (TN)
Shelby (AL)

Also, Johnson (SD), Cochran (MS), Harkin (IA), Landrieu (LA), Lautenberg (NJ), McConnell (KY), Reed (RI), Tester (MT), Voinovich (OH).

If these are your representatives we need you to write:

House Appropriations Subcommittee on Energy and Water Development:
Visclosky (IN)
Frelinghuysen (NJ)
Edwards (MD)
Pastor (AZ)
Davis (TN)

Or you live in these districts: IN-01, TX-17, AR-01, PA-02, NY-02, OH-17, MA-01, TN-04, CO-03, NJ-11, TN-03, ID-02, MT, CA-44 and LA-05.

We have a handout that you may wish to send with your letter.

For more background and a letter template, see this page.

Thanks for your efforts!

Candy Hansen

Japan Shoots for Robotic Moon Base by 2020


These ARE the droids we’ve been looking for. The Japanese space agency, JAXA, has plans to build a base on the Moon by 2020. Not for humans, but for robots, and built by robots, too. A panel authorized by Japan’s prime minister has drawn up preliminary plans of how humanoid and rover robots will begin surveying the moon by 2015, and then begin construction of a base near the south pole of the moon. The robots and the base will run on solar power, with total costs about $2.2 billion USD, according to the panel chaired by Waseda University President Katsuhiko Shirai.

Moon base robot. Credit: JAXA

Some of the planned droids weigh about 300 kg (660 pounds) and move on tank-like treads. Reportedly, they will be able to operate within a 100 km (60 mile) radius of the base. They’ll be equipped with solar panels, seismographs to investigate the moon’s inner structure, high-def cameras, and arms to gather rock samples, which will be returned to Earth via a sample return rocket.

The exact location for the base will be chosen from high-resolution images returned by Japan’s Kaguya orbiter, which has provided stunning images of the Moon’s surface.

Previously, JAXA had set a goal of constructing a manned lunar base starting in about 2030, and apparently, the robotic base would be a precursor. That plan calls for astronauts to visit the Moon by around 2020 which is about the same timetable as the Indian Space Research Organization (ISRO) is hoping to have a manned mission to the Moon. The China National Space Administration (CNSA) has said they would like to have a manned lunar mission in 2030. NASA? Not sure yet. The Constellation program to return to the Moon has seemingly been axed, but it’s not going down without a fight from members of Congress and others. But surely, even if NASA decides an asteroid or Mars is their destination of choice, they would have to start by practicing on the Moon.

Let’s all work together on this and perhaps returning to the Moon will actually happen.

Source: NODE via PopSci

What is the Air Force’s Secret X-37B Space Plane Doing in Orbit?


Last month’s launch of the US Air Force X-37B secret mini space plane has fueled speculation about the real mission of this vehicle and if it could possibly be used for a new type of military weapon. The X-37B launched on April 22, 2010 and has the ability to stay in orbit for up to 270 days. While the Air Force provided a webcast of the launch, since then there has been no word — leaked or official – about the status of the mission. “There has been a lot of speculation about what this vehicle could do and what sort of capabilities it could provide to the U.S. military, and some of that speculation was based on more science fiction than fact,” said Brian Weeden from the Secure World Foundation. “While a successful completion of the X-37B flight, landing, and turn-around will certainly be a significant step forward in reusable space vehicle technology, it is a long ways away from a single-stage-to-orbit capability.”

Weeden has put together a fact sheet on the X-37B, looking at the technical feasibility of some of the proposed missions for the mini space shuttle look-alike, and says that there’s almost no chance it could be used as a new weapon or a new weapon delivery system.

The X-37B will land unpiloted at Edwards Air Force Base in California. It uses solar arrays and lithium ion batteries to generate power instead of fuel cells like the space shuttle, a major reason why it can stay on orbit for much longer.

Artist impression of the Boeing X-37B (USAF)

Weeden said that after looking at all the proposed missions for the X-37B, he concluded the most likely probability is that it will be used as a flexible, responsive spacecraft to collect intelligence from space and as a platform to flight test new sensors and satellite hardware.

“One of the downsides to using satellites for collecting intelligence is that once they are launched they have a fixed set of sensors and capabilities,” Weeden said. “The X-37B brings to space the capability to customize the on-board sensor package for a specific mission, similar to what can be done with U.S. reconnaissance aircraft such as the U-2 and SR-71. In many ways, this gives the X-37B the best of both worlds,” he added.

Here’s a brief look at the potential uses for the X-37B:

On-orbit sensor platform and test bed, with the ability to return payload. “What it offers that we have seldom had is the ability to bring back payloads and experiments to examine how well the experiments performed on-orbit,” said Gary Payton, the undersecretary of the Air Force for space programs. “That’s one new thing for us.”

Given the R&D that likely was put into the X-37B, this approach probably isn’t very cost-effective, but Weeden said this is the most likely use the spaceplane. X-37B payload bay could hold various sensors used for intelligence collection of the Earth from space, potentially including radar, optical, infrared, and signals/electronic intelligence suites to flight-test and evaluate new sensors and hardware.

Deployment platform for operationally responsive space satellites. Weeden said this has a midrange chance of being X-37B’s mission, and he quotes Payton: “We could have an X-37 sitting at Vandenberg or at the Cape, and on comparatively short notice, depending on warfighter requirements, we could put a specific payload into the payload bay, launch it up on an Atlas or Delta, and then have it stay in orbit, do the job for the combatant commander, and come back home. And then the next flight, we could have a different payload inside, maybe even for a different combatant commander.”

But given it still would be dependent on the availability of EELV, it may not have a very quick response time for launch.

On-orbit repair vehicle. Weeden said this option has a fairly low chance of being X-37B’s real mission. While it could be used to rendezvous with malfunctioning satellites and repair or refuel them, the X-37B is limited in altitude (it has been rumored that it will have a maximum altitude range of 700 or 800 km (about 500 nautical miles), potentially high enough to access most Sun-synchronous satellites, but this is unconfirmed, plus not many existing operational military satellite components will fit in the X-37B cargo bay. And as the engineers who tried to figure out how to fix the Hubble Space Telescope robotically, without humans, on-orbit repair is extremely difficult, if not impossible.

Launch of the X37-B. Credit: Alan Walters (awaltersphoto.com) for Universe Today

On-orbit inspection of satellites. This option has a low potential, as well. The X-37B could be used to rendezvous and inspect satellites, either friendly or adversary, and potentially grab and de-orbit satellites. However, the X-37B cargo bay is much smaller than many operational satellites, and most of the space in the bay is likely to be filled by the required robotic arm and other gear.

Conventional Prompt Global Strike (CPGS) weapon or delivery system. Weedend says that chance of this being X-37B’s mission is zero. It could be launched in response to a pending crisis and remain on orbit for a length of time to respond to high value/very time sensitive targets. However, since the X-37B re-enters like the space shuttle and lands at an estimated 200 mph (321 kph), this means it travels in the atmosphere much slower than a ballistic arc or a hyperkinetic weapon, so it would need to carry conventional explosives to do any significant damage. Also, after re-entry would be a slow moving, not-very-maneuverable glide bomb, easy prey for any air defense system along its path to the target.

For more information, a four-page, fact-filled X-37B Orbital Test Vehicle Fact Sheet is now available on Secure World Foundation’s website.

Source: Secure World Foundation, special thanks to Leonard David.

Successful Test for Orion Launch Abort System

NASA successfully tested the pad abort system developed for the Orion crew vehicle on Thursday morning at the White Sands Missile Range near Las Cruces, New Mexico. The 97-second flight test was the first fully integrated test of the Launch Abort System developed for Orion. “It was a big day for our exploration team,” said Doug Cooke, NASA’s Associate Administrator for Exploration following the test. “It looked flawless from my point of view. This is the first abort system the US has developed since Apollo, but it uses much more advanced technologies. It was a tremendous effort to get to this point, designing such a complex system, and we’ve been working on this for about 4 years. I appreciate the amount of dedication and focus from the team. It was beautiful, a tremendous team effort.”
Continue reading “Successful Test for Orion Launch Abort System”

13 Things That Saved Apollo 13, Part 3: Charlie Duke’s Measles

Note: To celebrate the 40th anniversary of the Apollo 13 mission, for 13 days, Universe Today will feature “13 Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.

Just 72 hours before the scheduled launch of Apollo 13, Ken Mattingly was removed from the mission and replaced by Jack Swigert from the back-up crew as Command Module Pilot. Charlie Duke, also from the back-up crew caught the measles from one of his children, and exposed Mattingly — the only other member of either the prime or back-up crews who were not immune to the disease. If Mattingly were to come down with the measles, he might contract it while alone in the Command Module while Jim Lovell and Fred Haise were walking on the Moon.

“I think Charlie Duke’s measles contributed to the rescue,” said NASA engineer Jerry Woodfill, who has come up with “13 Things That Saved Apollo 13.” “This is one that probably everyone disagrees with me, but it seems like the astronauts on board were perfect to deal with what happened on the Apollo 13 mission.”

Woodfill says his conviction in no way denigrates the abilities of Ken Mattingly. “Ken was a wonderful crew member,” Woodfill said, “and he is a very detailed guy who helped with the rescue of Apollo 13 in a magnificent way. In the movie, Apollo 13, they capture the essence of how he is an ‘engineer’s engineer’.”

Astronaut Charlie Duke. Credit: NASA

Although, ironically Mattingly and Duke flew together later on the Apollo 16 mission, were it not for Charlie Duke’s measles, Woodfill said that Swigert’s special talents for an Apollo 13-type mission would not have been present.

Jack Swigert. Credit: NASA

First of all, his physique was better suited to the harsh conditions he experienced in the inoperable Command Module, where he was positioned for most of the flight. Woodfill said that likely, Swigert’s brawn as a former University of Colorado varsity football player better served him to withstand the cold conditions and endure the small amounts of water that the astronauts had to ration among themselves.

Water was one of the main consumables – even more than oxygen – of which the crew barely had enough.

“Mattingly and Haise had about the same build,” said Woodfill, “which was not as robust a build as Swigert and Lovell. Haise ended up with a urinary tract infection because of not getting enough water.”

But more importantly were Swigert’s familiarity with the Command Module and his “precise” personality.

Screenshot from Apollo footage of Jim Lovell and Jack Swigert. Credit: NASA

“Among the nearly thirty Apollo astronauts, Jack Swigert had the best knowledge of Command Module malfunction procedures,” said Woodfill. “Some have said that Jack had practically written the malfunction procedures for the Command Module. So, he was the most conversant astronaut for any malfunction that occurred in the CSM.”

Swigert had to quickly and accurately write down the procedure to transfer the guidance parameters from the CSM computers to the Lunar module computers. And the procedure for the reentry of the crew to Earth’s atmosphere had to be re-written, with Mission Control calling up to the crew with hundreds of changes to the original plan. “The team on the ground had to recreate a checklist and a procedural ‘cookbook’ that would normally take three months to create, and they had to do it in just days. Jack had to be accurate when he wrote down these procedures. And the communication system wasn’t always the best – it was sometimes garbled or couldn’t be heard very well. While all the astronauts had to have orderly minds, Jack Swigert was a man of extreme order.”

Woodfill said an account from Swigert’s sister bears out that fact. She at one time asked her brother Jack to put away cans of frozen orange juice and lemon juice in her freezer. When she looked in her freezer later, all the lemon juice cans were lined up in orderly fashion, with the orange juice cans neatly lined up in an adjacent row. Later, she asked her brother why he had neatly lined all the lemon cans in a row then a row of orange juice cans, and according to Woodfill, Swigert answered, “Because “L” comes before “O” in the alphabet.”

“The truth is, Swigert was gifted with a respect for extreme order and precision, and he was onboard for just that reason,” said Woodfill. “Every one of the steps in the rescue checklist had to be ‘in the right order’.”

Fred Haise, in 1966. Credit: NASA

And, equally important, said Woodfill, was the talent Haise brought to recording and rewriting operational procedures. “Fred had been a newspaper stringer for a small newspaper in Mississippi in his youth, taking notes and editing them for his local Mississippi paper’s stories. Utmost among reporters is accuracy in quoting sources. Those transmitted words from mission control had to be flawlessly transcribed if the crew was to survive, and Fred and Jack did an amazing job.

Remarkably, said Woodfill, each man’s talents specifically served the unique need. “Each man exhibited exceptional accuracy in adverse surroundings,” he said. “The lander was noisy, the audio sometimes fuzzy, movement unpredictable, temperatures cold, sleep scarce, and fatigue always present.”

Of course, those familiar with the Apollo 13 story know that Ken Mattingly never got the measles. But the role he played in getting the astronauts back home safely can’t be overestimated.

“Call it luck, call it circumstance,” said Woodfill, “but because of Charlie Duke’s measles the men on board Apollo 13 — and back on the ground — were perfect for the situation they encountered.”

Other articles from the “13 Things That Saved Apollo 13” series:


Part 1: Timing

Part 2: The Hatch That Wouldn’t Close

Part 4: Using the LM for Propulsion

Part 5: Unexplained Shutdown of the Saturn V Center Engine

Part 6: Navigating by Earth’s Terminator

Part 7: The Apollo 1 Fire

Part 8: The Command Module Wasn’t Severed

Part 9: Position of the Tanks

Part 10: Duct Tape

Part 11: A Hollywood Movie

Part 12: Lunar Orbit Rendezvous

Part 13: The Mission Operations Team


Your Questions about Apollo 13 Answered by Jerry Woodfill (Part 1)

More Reader Questions about Apollo 13 Answered by Jerry Woodfill (part 2)

Final Round of Apollo 13 Questions Answered by Jerry Woodfill (part 3)

Never Before Published Images of Apollo 13’s Recovery

Listen to an interview of Jerry Woodfill on the 365 Days of Astronomy podcast.

13 Things That Saved Apollo 13, Part 2: The Hatch That Wouldn’t Close

Note: To celebrate the 40th anniversary of the Apollo 13 mission, for 13 days, Universe Today will feature “13 Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.

When the oxygen tank exploded on the Apollo 13 Command Module, the astronauts on board and everyone in Mission Control had no idea what the problem was. In his book, “Lost Moon,” Apollo 13 commander Jim Lovell thought the “bang-whump-shudder” that shook the spacecraft could have been a rogue meteor hit on the lunar module, Aquarius. Quickly, he told Jack Swigert to “button up” or close the hatch between the Command Module Odyssey, and Aquarius, so that both spacecraft wouldn’t depressurize.

But the hatch wouldn’t close.

Apollo engineer Jerry Woodfill believes the balky hatch was one of the things that helped save the Apollo 13 crew. “They were trying to close off the only way they could save their lives,” he said.

In Mission Control and in the nearby Mission Evaluation Room, several engineers, including Woodfill, thought the only explanation for so many systems to go offline at once was an instrumentation problem. “Initially I thought there was something wrong with the alarm system or the instrumentation,” said Woodfill, who helped develop the alarm system for the Apollo spacecraft. “There was no way so many warning lights could illuminate at once. I was sure I would have some explaining to do about the system.”

Screenshot from Apollo 13 footage of Fred Haise floating through the hatch between Odyssey and Aquarius. Credit: NASA

At first, Lovell thought Fred Haise may have been playing a joke on the crew by actuating a relief valve that made a sort of popping noise – something he had done previously during the flight. But with the surprised look on Haise’s face, along with the noise and all the alarms going off, Lovell’s next thought was the hull had been compromised in Aquarius.

Like a submarine crew that closes hatches between compartments after being hit by a torpedo or depth charge, Lovell wanted to close the hatch into the Command Module so all the air didn’t rush out into the vacuum of space.

Swigert quickly tried three times to close the hatch, but couldn’t get it to lock down. Lovell tried twice, and again couldn’t get it to stay closed. But by that time, Lovell thought, if the hull had been compromised, both spacecraft surely would have already depressurized and no such thing was happening. So, the crew set the hatch aside and moved on to looking at the falling gauges on the oxygen tanks.

And shortly after that, Lovell looked out the window and saw a cloud of oxygen venting out into space.

Earlier in the flight, the Apollo 13 crew had opened the hatches between Odyssey and Aquarius, and actually was far ahead on their checklist of preparing to land on the Moon by turning on equipment in the lander.

Woodfill believes this was fortuitous, as was the hatch not closing, because saving time was of the essence in this situation.

“Some people say that doesn’t amount to much time,” Woodfill said, “but I say it did, because if they had closed and latched up the hatch, and then worked to find the real problem of what was wrong, then they would have to delay and quit working the problem to go remove the hatch, stow the hatch and go power up the lander.”

Why was time so important?

The fuel cells that created power for the Command Module were not working without the oxygen from the two tanks. “Tank 2, of course, was gone with the explosion,” said Woodfill,” and the plumbing on Tank 1 was severed, so the oxygen was bleeding off from that tank, as well. Without oxygen you can’t make the fuel cells work, and with both fuel cells gone they know they can’t land on the Moon. And then it became a question of whether they can live.”

But over in Aquarius, all the systems were working perfectly, and it didn’t take long for Mission Control and the crew to realize the lunar module could be used as a lifeboat.

Screenshot from Apollo 13 footage of Jim Lovell and Jack Swigert during the mission. Credit: NASA

However, 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 needed to keep 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 just a couple of hours during the time the crew would jettison the Service Module and reenter with only the tiny Command Module capsule.

“Those batteries are 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 re-open the hatch helped those emergency batteries have just enough power in them so they could recharge them and reenter.”

It’s interesting when the hatch had to work correctly, when the lander was jettisoned for re-enty, it worked perfectly. But at the time of the explosion, it’s malfunctioning kept the pathway to survival into the LM open, saving time. Being able to get into the lunar lander quickly was what helped save the crew’s life.

Tommorow: Part 3: The measles

Additional articles from the “13 Things That Saved Apollo 13”


Part 1: Timing

Part 3: Charlie Duke’s Measles

Part 4: Using the LM for Propulsion

Part 5: Unexplained Shutdown of the Saturn V Center Engine

Part 6: Navigating by Earth’s Terminator

Part 7: The Apollo 1 Fire

Part 8: The Command Module Wasn’t Severed

Part 9: Position of the Tanks

Part 10: Duct Tape

Part 11: A Hollywood Movie

Part 12: Lunar Orbit Rendezvous

Part 13: The Mission Operations Team


Your Questions about Apollo 13 Answered by Jerry Woodfill (Part 1)

More Reader Questions about Apollo 13 Answered by Jerry Woodfill (part 2)

Final Round of Apollo 13 Questions Answered by Jerry Woodfill (part 3)

Never Before Published Images of Apollo 13’s Recovery

Listen to an interview of Jerry Woodfill on the 365 Days of Astronomy podcast.

13 Things That Saved Apollo 13, Part 1: Timing


Note: To celebrate the 40th anniversary of the Apollo 13 mission, for the next 13 days, Universe Today will feature “13 Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill. Click here for our preview article.

Oxygen Tank two in the Apollo 13 Service Module exploded at Mission Elapsed Time (MET) 55 hours and 55 minutes, 321,860 kilometers (199,990 miles) away from Earth. 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. “Not everyone agrees with all the things I’ve come up with in my research,” said NASA engineer Jerry Woodfill who has studied the Apollo 13 mission in intricate detail, “but pretty much everyone agrees on this, including Jim Lovell. The timing of when the explosion happened was key. Much earlier or later in the mission would have prevented a successful rescue.”

If the explosion happened earlier (and assuming it would have occurred after Apollo 13 left Earth orbit), 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. Had it happened much later, perhaps after astronauts Jim Lovell and Fred Haise had already descended to the lunar surface, there would not have been the opportunity to use the lunar lander as a lifeboat.

But looking at why the explosion happened when it did shows how fortuitous the timing ended up to be.

The control panel of the Apollo 13 capsule. The module is on display at the Kansas Cosmosphere and Space Center in Hutchinson, KS. Photo courtesy Kansas Cosmosphere and Space Center.

The explosion occurred when Jack Swigert flipped a switch to conduct a “stir” of the O2 tank. The Teflon insulation on the wires to the stirrer motor in O2 tank 2 had unknowingly been damaged because the manufacturer failed to update the heater design for 65 volt operation, and the tank overheated during a pre-flight test, melting the insulation. The damaged wires 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.

The O2 tanks were stirred in order to get an accurate reading on the gauging systems, as the cryogenic oxygen tends to solidify in the tanks, and stirring allows for a more accurate reading on the quantity of O2 remaining in the tank.

But this was not the first time the crew had been ordered to stir the tank. It was the fifth time during the mission. And most interestingly, the tanks normally were stirred approximately once every 24 hours. So, why was it stirred that often?

In what Woodfill said was a problem unrelated to what caused the explosion, the quantity sensor or gauge was not working correctly on O2 tank 2. The EECOM (Electrical Environmental and Consumables) flight controller in Houston discovered that the quantity sensor was not reading accurately, and because of that Mission Control asked the astronauts to perform additional actuations of the stirrer to try and troubleshoot why the sensor wasn’t working correctly.

So, it took five actuations until the short circuit and the resulting fire and explosion occurred. If the gauge had been working correctly and the normal stirring of the tank had been done, that would have put the time of the fifth stirring after Lovell and Haise had departed for the lunar surface, and the rescue scenario that ultimately was carried out couldn’t have happened.

“Check the arithmetic,” said Woodfill. “Five actuations at 24 hour periods amounts to a MET of 120 hours. The lunar lander would have departed for the Moon at 103.5 hours into the mission. 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.”

Apollo 13 crew: Jim Lovell, Jack Swigert and Fred Haise. Credit: NASA

Who knows what would have happened to the crew? The fuel cells required the liquid oxygen tanks. This meant no production of electrical power, water and oxygen. The attached lunar lander had to be available. Likely, the two ships couldn’t even have docked back together. And what if the accident had happened behind the Moon without mission control’s help? Alone in the Command module, Swigert would have had difficulty analyzing the problem. Without a fueled lunar lander descent stage attached, lacking its consumables and engines as well as the needed battery power, water and oxygen, the crippled Command Module could not have returned to Earth with live astronaut(s). Not only would Lovell and Haise have perished but Swigert’s fate would have been the same. Even if the damaged Service Module’s engine had worked, no fuel cells meant the ship would die. The situation that the Apollo 13 crew actually faced was dire, but the alternative scenario would certainly have been fatal.

Woodfill contends that the quantity sensor malfunction assured the lunar lander would be present and fully fueled at the time of the disaster. It was an extremely fortuitous event. Had it not occurred, the timing of the explosion would have been far different and the crew would have perished.

Additional Articles from the “13 Things That Saved Apollo 13” series that have now been posted:


Part 2: The Hatch That Wouldn’t Close

Part 3: Charlie Duke’s Measles

Part 4: Using the LM for Propulsion

Part 5: Unexplained Shutdown of the Saturn V Center Engine

Part 6: Navigating by Earth’s Terminator

Part 7: The Apollo 1 Fire

Part 8: The Command Module Wasn’t Severed

Part 9: Position of the Tanks

Part 10: Duct Tape

Part 11: A Hollywood Movie

Part 12: Lunar Orbit Rendezvous

Part 13: The Mission Operations Team


Your Questions about Apollo 13 Answered by Jerry Woodfill (Part 1)

More Reader Questions about Apollo 13 Answered by Jerry Woodfill (part 2)

Final Round of Apollo 13 Questions Answered by Jerry Woodfill (part 3)

Never Before Published Images of Apollo 13’s Recovery

Listen to an interview of Jerry Woodfill on the 365 Days of Astronomy podcast.

Where Is NASA Going and How Are We Going to Get There?


Everyone seems to be a little confused and in the dark about the direction NASA will be headed if Obama’s proposed FY2011 budget passes. Yesterday’s hastily called press briefing answered a few question, but not the big issues of where we’ll be going and how we’re going to get beyond low Earth orbit. Yes, Bolden did say that Mars is the ultimate destination but everyone knows we can’t just pick and go to Mars. NASA needs a vehicle to get there, and getting there will require doing it in incremental steps, such as going to the Moon or asteroids first. There’s no plan (yet) for a vehicle and no plans for those incremental steps. Hopefully Obama’s “Space Summit” on April 15 will provide some answers.

I’m of two minds about this whole deal.

First, I love the space shuttle. I’ve just spent two months at Kennedy Space Center. I experienced the launch of Endeavour, got to see Endeavour and Discovery up closer than I ever imagined, saw behind the scenes processing, met people who work with the shuttles every day, and talked with people whose livelihood depends on NASA sending people to space.

And admittedly, any talk of extending the shuttle program makes my heart leap just a little. It’s a beautiful, marvelous, incredible machine – many say the most complex device ever invented by humans. And why shouldn’t we keep flying it? NASA managers like Mike Moses, Mike Leinbach and John Shannon say that since the Columbia accident we now know the shuttle and understand the risks better than ever. Right now, it definitely would be safer to fly on a shuttle than to fly on a new, untested commercial rocket.

And the jobs lost – not only at KSC but at Johnson Space Center, other NASA centers and contractors — by ending the shuttle and canceling Constellation means individuals who have these incredible skill sets for getting people to space may not be needed anymore. There are things they know that just can’t be replaced, replicated or restarted five or ten years down the road.

Bolden said yesterday that there should be new jobs under the new budget which provides more money for NASA, but nobody really knows yet how many and where.

One of the most poignant questions asked by a reporter at yesterday’s press briefing came at the very end: What’s to say that when a new administration enters the White House that we won’t come back to starting over again with a whole new program?

“If we execute the budget as proposed and prove that we are on a sustainable path, that is the best protection for a subsequent administration not having to change course,” said Lori Garver, Deputy NASA Administrator. “That’s the goal, to not be in this position every four years. These technologies we will be developing will allow us to leave low Earth orbit and go to interesting places. We’ll be able to determine the best places to go, and we should have the data to do it and the capabilities to do it that are more affordable, which has been the goal since the beginning to the space program.”

So this is where my other mind kicks in.

Change is hard. It’s really hard when people’s lives and livelihood are affected. But without change, we get comfortable and getting comfortable means we do the same things over and over.

Running NASA the same way ever since the end of Apollo, while giving us the amazing vehicle that is the space shuttle, has not gotten humans beyond low Earth Orbit, and I think everyone agrees we want to be able to go other places.

Last year NASA turned 50 and there were some comments about NASA reaching middle age and acting like it, too. Change is what keeps us young, and change keeps us on our toes. When you’re willing to change and get out of your comfort zone, you make a commitment to the unknown. And that’s what NASA should be all about. Our memories can’t be bigger than our dreams.

Perhaps the hardest thing about these proposed changes to NASA is that Obama and Bolden are asking for change without telling us exactly what the change is. Maybe they don’t know yet, but this is something we can’t just figure out along the way.

There’s the famous saying that life is not about the destination but the journey, or the other saying that the best thing about being in a race is competing in it. But most journeys have a map and most races have a finish line.

If the proposed budget and plan goes through, this will give us a shot at journeying beyond. Now we just need to know where we’re going and how we’re going to get there.

I started writing this to report on yesterday’s briefing by Charlie Bolden, Lori Garver and other NASA officials, but clearly it turned into something different. Here are a few links to articles by other journalists who wrote about the briefing and what might be coming next:

Reuters: NASA Maps Plan for Revamped Space Program

NASA Chief Maps Out Space Agency’s Future Beyond Shuttle by Tariq Malik at Space.com

NASA Chief Charts Agency’s Shuttle-Less Future by Seth Borenstein, AP

The Write Stuff Blog at the Orlando Sentinel quickly distills what the changes will mean for the different NASA Centers:

Plans for Kennedy Space Center under Obama 2011 budget

What JSC can Expect from the NASA Reshuffle

What Marshall Can Expect from the NASA Reshuffle

Houston Chronicle’s Eric Berger, The SciGuy: Job Cuts Worry Space Center Boss and Answers Coming Today on NASA’s Future

Congressional Reactions to NASA’s Work Assignments by Jeff Foust at Space Politics

NASA Announces Programs and Costs for the Next Five Years by Dennis Overbye, New York Times

And finally, this NASA budget page provides links to all the NASA documents published about the new budget

Astronaut Explains Why We Should Return to the Moon


The debate on why humans should or should not return to the Moon has been ongoing for years. Two weeks ago, I had the opportunity to hear astronaut Ron Garan speak eloquently on a subject he is passionate about, water sustainability on planet Earth. Subsequently, I read an essay Garan wrote about the importance of returning to the Moon. Although Garan originally wrote this essay before the cancellation of the Constellation program was announced, he has amended his thoughts to reflect the likelihood that the US won’t be returning to the Moon anytime soon. With Garan’s permission, we are re-publishing his essay in its entirety.

The Importance of Returning to the Moon
(The 8th Continent)
By Ron Garan
NASA Astronaut

On May 10th, 1869, a golden spike joined two railways at Promontory Point, Utah, and the first transcontinental railroad was completed. On January 14th, 2004, a new vision for our Nation’s space exploration program was announced that committed the United States to a long-term human program to explore the solar system starting with a return to the moon. On February 1st 2010, those plans to return to the moon were put on hold. Although our Nation has decided to postpone a return to the moon it is still important to acknowledge the moon’s relevance to life on Earth.

There is no doubt that the railroad changed the world. It opened up frontiers to discovery, settlement, and commerce. The railroad was the backbone for the industrial revolution that provided the largest increase in life expectancy and improvement in quality of life in history. Just as the industrial revolution brought about unprecedented improvements in quality of life so can a new age of space exploration and development, but this time with a positive impact on the environment. To begin a period of sustainable space exploration, both the public and private sectors of our Nation must seize the opportunity and continue on a path to the moon.

Artist impression of humans on the Moon. Credit: NASA

Since the Vision for Space Exploration was announced in 2004, there has been an on-going debate about the importance of taking the next step in space exploration, a return to the moon. The reasons for making this the next step include: fulfilling a compelling human need to explore; gaining a foothold on the moon to prepare for journeys to other worlds; easing the world’s energy problems; protecting the planet from disasters; creating moon-based commercial enterprises that will improve life on Earth, conducting scientific research; inspiring young people toward higher education, and utilizing space resources to help spread prosperity throughout the world.

We should not return to the moon for any one of these reasons, but for all of them and more. By first establishing the basic infrastructure for a transportation system between the Earth and the moon and a sustainable, semi-autonomous, permanent human settlement, we will open the door to significant benefits for all. Of course, any permanent lunar base must be economically and politically sustainable and therefore must provide tangible benefits and a return on investment.

Ron Garan ready for an EVA in June 2008. Credit: NASA

Exploration: Great nations accomplish extraordinary endeavors that help to maintain their leadership in the world. America’s history is built on a desire to open new frontiers and to seek new discoveries. NASA’s vision for space exploration acknowledges that, “Mankind is drawn to the heavens for the same reason we were once drawn into unknown lands and across the open sea. We choose to explore space because doing so improves our lives and lifts our national spirit.”
Establishing a lunar infrastructure will challenge us to improve the reliability of space transportation and allow us to demonstrate exploration systems and concepts without leaving the relative safety of near-Earth space. Testing systems and concepts at a location that’s a three-day journey from Earth is a logical step before we make the leap of a six-month journey to Mars. Establishing a permanently occupied lunar base also will open the way to detailed study and use of lunar resources, which likely are significantly more economical than lifting all required exploration resources from the Earth’s surface.

Energy: Today, about 1.6 billion people on the Earth don’t have access to electricity. The World Bank estimates that 1.1 billion people live in extreme poverty which leads to 8 million premature deaths every year. In developed countries, higher quality of life is achieved only through a high rate of energy use. Increased energy supply is needed for economic and social development, improved quality of life, and to grow enough food to provide for the citizens of the developing world.

Unless something is done soon, the world will be faced with a crisis of enormous proportions. The United Nations estimates that world population will be approximately 9.1 billion by 2050 with virtually all growth in the 50 poorest countries. The choices that the global society makes to provide for future energy needs will have a profound effect on humanity and the environment.

The moon can supplement Earth-based renewable energy systems to meet future energy demand. Ample energy from the Sun reaches the moon and is not interrupted by weather, pollution or volcanic ash. Solar energy farms on the moon can “beam” limitless clean energy down to where it is needed on Earth or to satellites for relay to the Earth. There are also other potential sources of energy including platinum for fuel cells and an isotope called helium-3, which could be used in fusion reactors of the future.

Supplying energy from the moon will enable us to help provide the Earth’s energy needs without destroying our environment.

Artists impression of an asteroid flying by Earth. Credit: NASA

Protect the Planet from Disasters: There is a real risk to the Earth’s inhabitants from asteroid impacts and super-volcano eruptions. If a large object the size of Comet Shoemaker-Levy 9 that recently slammed into Jupiter were to hit the Earth, civilization could be destroyed. Much smaller asteroids could cause tremendous damage and loss of life. The moon is a superb location for early detection systems.

A super-volcano eruption is a geologic event of enormous explosive power to affect the global climate for years. Scientists estimate the last such eruption happened 74,000 years ago, and was 10,000 times more powerful than Mount St. Helens. Tremendous amounts of rock and ash were ejected into the air causing a six year long volcanic winter and a 1,000-year instant Ice Age, massive deforestation, disastrous famine, and near extinction of humankind. Scientists estimate that such a super-eruption will occur about once every 100,000 years.

The systems and technology that will be developed for life and work on the moon can be used to develop habitats and systems that could preserve Earth’s inhabitants in the event of a devastating eruption. These systems will also improve our ability to live in extreme environments and can be used to learn how to overcome limited resources and other environmental issues.

Astronaut Ron Garan takes a moment to pose for a picture during training for his April 3-20 stay inside the Aquarius Underwater Laboratory off the coast of Key Largo, Florida. Credit: NASA

Moon-Based Commercial Enterprises: When the early pioneers headed west and expanded our Nation, they did not carry everything with them that they would need for their journey. They “lived off the land” and we will also need to use those resources available to us along our journey, starting with the moon.

There are numerous moon-based commercial activities that could significantly offset the cost of a moon base. Just a few of these are lunar refueling or servicing stations for satellites, lunar mining and space tourism. These commercial activities would allow us to return national treasures from space and provide a significant return on our space investment.

Scientific research: The moon offers an incredible opportunity to further human understanding and discovery. Since the moon’s ancient surface is relatively undisturbed, study of its geology can help us better understand the geological history of Earth. Further, the moon’s vacuum environment can’t be duplicated on the Earth or in low-Earth orbit, and could lead to new materials, advanced alloys, medicines and innovative ways to deal with limited resources on Earth. Radio telescopes on the far side of the moon would be shielded from all radio signals (noise pollution) from Earth, allowing tremendous sensitivity increases and telescopes pointed at the Earth could identify and predict weather and climate changes.

If we return to the moon just for science and exploration then activities will be limited by the amount of money our nation is willing to devote. But, if we establish a sustainable, economically viable lunar base then our science and exploration will be limited only by our imagination.

Education: Our children are our best investment for the future, and our space program is a tremendous motivator. Our Nation has seen a steady decline in the number of students studying math and science. The space program can help turn this trend around. I can personally attest to the ability of the space program to encourage students based on the fact that I enrolled in math and science courses and began the pursuit of an engineering degree the day after the first space shuttle mission landed. The creation of a permanent lunar base will inspire millions of young people toward higher education and help maintain our Nation’s technological leadership.

Astronaut Ron Garan, STS-124 mission specialist, participates in the mission's first EVA in June 2008. Credit: NASA

Resources and Other Benefits: Since we live in a world of finite resources and the global population continues to grow, at some point the human race must utilize resources from space in order to survive. We are already constrained by our limited resources, and the decisions we make today will have a profound affect on the future of humanity.

Using resources and energy from space will enable continued growth and the spread of prosperity to the developing world without destroying our planet. Our minimal investment in space exploration (less than 1 percent of the U.S. budget) reaps tremendous intangible benefits in almost every aspect of society, from technology development to high-tech jobs. When we reach the point of sustainable space operations we will be able to transform the world from a place where nations quarrel over scarce resources to one where the basic needs of all people are met and we unite in the common adventure of exploration. The first step is a sustainable permanent human lunar settlement.

Artist concept of the Orion capsule in orbit around the Moon. Credit: NASA

How should we go about this important undertaking? A good analogy to look at is the U.S. railroad system. The greatest obstacle for the first railroad developers was financial risk. Purchasing right of way, paying wages for large workforces and buying materials and equipment were prohibitively expensive. But the federal government stepped in, orchestrating massive land grants and other incentives. Once initial government investment was assured, enterprising developers invested enormous sums to bridge vast valleys and tunnel through enormous mountains.

Today we are faced with similar obstacles in the development and use of space for the benefit of humanity. Potential space developers face enormous up-front costs for high-risk, long-term returns on investment. To capitalize on the tremendous moon-based opportunities, our nation should establish the basic infrastructure for a transportation system between the Earth and the moon and a sustainable human settlement on the moon. Once this initial investment is made, commercial revenue-generating activities can be established. Just as our investment in the railroad, interstate road system, hydro-electric dams and other large federal projects have been paid back many times over by increased productivity and quality of life, so will our investment in lunar infrastructure.

We are poised on the doorstep of an incredible opportunity to benefit all of humanity. We have the technology and the ability to make this a reality — we need only the will to see it through. We need to choose a course toward the utilization of space to increase our available resources, global prosperity, quality of life, technological advancement, and environmental stewardship. Just as we look back and thank those before us for developing things most of us take for granted such as railroads and highways, the generations to come should be able to look back and thank us for committing to sustainable space exploration.