Tuesday, November 30, 2010

Demanding Design Boosts Shuttle Engine

A space shuttle main engine burns at 6,000 degrees F, but the outside of the nozzle remains cool to the touch. Prior to launch, sometimes it even frosts over.

The nozzle technology that allows a finger-width of ridged metal to contain and steer flames that would boil iron is just one of the scores of innovations designers came up with for the engines three decades ago.

Such advances were critical if NASA was going to realize its plans for a reusable space shuttle that, unlike the previous rockets, would not use its engines once and then drop them in the ocean.

Some of the others:
- A system that lets the engines be incrementally throttled up and down depending on the needs of the mission
- A hydrogen turbopump that spins 567 times a second with each 2” tall turbine blade generating 700 horsepower.
- A computer that runs 50 health checks on the engine every second using data from 200 sensors
- A system of pipes, or ducts, that withstand pressures as high as 7,000 pounds per square inch- A main combustion chamber strong enough to contain the explosion of 970 pounds of oxygen and 162 pounds of hydrogen fuel every second, continuously for 8 1/2 minutes
- The only heavy-lift booster engine that continuously performs all the way from launch pad to orbit- Engineering and materials that allow the engine to be reused multiple times
- A compact, efficient design that produces 8 times the thrust of a modern high performance jet engine per each pound of weight.

Added together, the innovations became a rocket engine that is more than 99.9 percent efficient, which means that almost all of its hydrogen and oxygen is used to create thrust. For comparison, an automobile engine is about a third as efficient, since most of its energy is created in the form of heat that does not turn the wheels.

"Everything in that engine is a whole science field," said Carlos Estrada, NASA's Main Propulsion Branch chief at Kennedy Space Center. "You look at the materials, you look at the components, you look at the way they designed that engine, how it's all designed for the different stages with the pump and pressures. I mean, every time you look at a component you have all these people with expertise in it."

Three main engines are used to launch a shuttle into orbit, along with help from a pair of solid-fueled boosters that separate two minutes after launch.

The advances did not come easily for designers who, working in the 1970s before computer-assisted design became commonplace, ran many of their calculations on slide rules and used judgments based on the experience they gained building massive engines for the Saturn V moon rocket.

Getting the start sequence correct alone took about a year of testing, fixing and more testing, said Dan Hausman, Pratt & Whitney Rocketdyne's site director at Kennedy. "We kept burning up the turbine blades, getting temperature spikes. Our analog models weren't that good with the start sequence. We had to figure out how to get it started because everything had an idiosyncrasy."

The idiosyncrasies he talks about are no small matter considering a single main engine creates more than four times the horsepower of the Hoover Dam.

When most people think of an engine, they usually picture a part of the engine called a bell or nozzle. It's the part that everyone sees at launch shooting flames and supersonic exhaust. Although a lot is happening inside the bell, it's one of the least active parts of the machine during launch. The real action is taking place in front of the engine bell in a maze of hidden machinery called the powerhead.

"The powerhead is the meat of the engine," said Stephen Prescott, a Pratt & Whitney Rocketdyne engineer specializing in the engine's turbopumps. "The nozzle is what's actually allowing us to gather the thrust, but the powerhead is what actually gives us the thrust."

The powerhead is home to four turbopumps, a robust computer controller and a network of ducts, wiring and valves designed to release 500,000 pounds of thrust without exploding. For as much power as it releases, the powerhead is not imposingly large. Standing above the nozzle in a workstand, the powerhead reaches about six feet from the floor. The high-pressure hydrogen turbopump, the strongest of the four, would fit on a desk.

"You run into some people who think it's easy," Hausman said. "Anybody who thinks it's easy doesn't understand it. Once you understand it, that's a marvel of engineering. It's a marvel that people can build it, and operate it and work it at the high reliability that we've done."

The first space shuttle main engine ignition took place well before Columbia lifted off on April 12, 1981, to inaugurate the space shuttle era. It happened in the mid-1970s at a concrete and steel test stand at NASA's Stennis Space Center in Mississippi where engineers and designers could put an engine through its paces without worrying about sacrificing a spacecraft and its payload if something went wrong.

And things went wrong, especially in the beginning. The liquid oxygen turbopump blew up. The hydrogen turbopump blades broke and exploded the whole thing. There was the occasional combustion instability, which is a polite way of saying the controlled exhaust thrust went out of control and, you guessed it, blew the engine up.

In fact, the first engine test Hausman saw in person at Stennis ended with a puff of black smoke and half the engine sitting at the bottom of the stand.

"There wasn't much left, it was all kind of a molten mass of dripping metal because when liquid oxygen eats metal, there's no evidence left because metal vaporizes," Hausman explained. "Twenty milliseconds, 40 milliseconds, 60 milliseconds, the engine's gone. Very fast."

It is that speed that keeps the shuttle engine's mechanics on their toes as they carefully evaluate every engine after a flight.

"We have a line from John Plowden, one our most senior engineers, that’s embedded in the DNA of everyone here: Never turn your back on a rocket engine," Prescott said. "Knowing what this engine can do to itself in a split second is what keeps us focused on knowing you can't just brush off something that you think is fine."

While spectacular malfunctions on the engines were a mark of the early part of the engine development, fixing them effectively and retesting over and over would become a hallmark of the main engine program.

"The key was test, test, test," Hausman said. "In the development program, the best learning we could ever do was have an engine blow up at Stennis, because we could find an issue and go fix it."

"Any part that flew here at Kennedy had a counterpart that operated twice as long at Stennis," Hausman said.

Stennis recorded 2,000 main engine test firings between 1975 and 1992. More firings, including flight certification tests for every engine used on a shuttle, took place until July 29, 2009, bringing the total to over 2,300 engine firings at that one facility.

Hausman credits the careful development work with setting up the engine to successfully cope with problems during a shuttle launch, though there were very few of those throughout the shuttle's 130-plus missions.

A shuttle mission has never failed because of the main engines, though there were a couple close calls. The first came in 1985, when one of Challenger's three main engines shut down during ascent, prompting the crew to fly to a lower orbit. The Spacelab mission still was successful and engineers traced the problem to one of the sensors on the engine that shut down.

A series of failures occurred during the launch of Columbia in 1999, when a pin broke loose inside the main combustion chamber and popped a couple tiny holes in three of the 1,080 hydrogen tubes in the nozzle. There also was a pair of short circuits in Columbia’s electrical system during ascent which resulted in a loss of electrical power on the primary channel to the engines. The redundant safety features designed into the engine allowed the controller to seamlessly transfer control to an alternate channel and continue on with the mission.

Eileen Collins commanded the flight and Columbia was able to reach orbit and deploy the groundbreaking Chandra X-ray observatory just as was planned.

Prescott was watching that launch and listening to the transmissions back and forth between controllers and the shuttle crew.

"We knew something had gone on, but we weren't quite sure just what had happened," Prescott said. "Eileen, that was the most perfect example of what kind of training those astronauts go through, because she was just so calm, cool and collected."

Engineers dove deeply into the engine after Columbia's return to find out what went wrong.

"That was pretty scary," Estrada said. "That was a big deal."

Another engine safety feature was demonstrated during Columbia’s third mission in 1982 when one of the orbiter’s three auxiliary power units shut down late into the launch, resulting in a loss of hydraulic power to one main engine. That engine’s backup electrical control system maintained control and performance until reaching orbit which was then followed by a fail-safe, pneumatically-actuated main engine cut-off.

Hausman said the redundant systems built into the engines paid off during those situations.

A great deal of effort and research went into developing the shuttle's main engines, but maintaining them and keeping them healthy during the shuttle's 30-year career has been equally advanced and careful.

"I came in around 1996, and to me it was amazing to see how much people needed to know to be able to manage such a piece of equipment," Estrada said.

The engines' overseers spend hours peering with one eye shut into a small borescope, basically a long, black, flexible fiber optic hose with a lens at one end and an eyepiece at the other. Doctors use them frequently to examine patients. The engineers are looking for anything amiss, whether it be a weld in one of the turbopump housings, a tiny hole in a pipe, unusual wear or erosion or something they've never seen before.

"Keeping the discipline of what you do and how you do it is critical," Estrada said.

It is repetitive and painstaking work that takes a full shift to complete on each major component of the engine. And that does not count all the other extensive inspections performed before an engine launches again.

"Pretty much everything on this engine is criticality one," Prescott said. "We can’t even so much as lose a fastener and not create a problem because we're pretty close to the limits on everything on this engine."

When the technicians find something amiss, no effort is too much to track it down and fix it.

"It's a three-dimensional puzzle that sometimes, like a Rubik's Cube, you don't even know you’re close to getting it together until all the sudden, the thing's solved in front of you," Prescott said. "We've been known to chase our tails trying to get just perfect alignment and before you know it, there it is, everything can go together."

Throughout the shuttle's operation, designers kept improving the machinery. The sensors were steadily improved to make them more robust, the powerhead was redesigned to reduce pressures inside the transfer tubes and smooth the fuel flow, and the main combustion chamber throat area was enlarged to de-rate the engine and add extra operating margin. The modified heat exchanger eliminated welds and was strengthened.

Perhaps one of the biggest changes came when additional robustness was designed into the high pressure turbo-machinery. Overall, these design changes resulted in an additional 700 pounds of weight, but increased safety by a factor of 3 over earlier configurations. A final engine upgrade was introduced in 2007 when the advanced health management system became active, providing an additional 23 percent safety improvement during ascent.

Why put so much effort into the engines? Hausman credits rocket pioneer and Saturn V developer Werner von Braun with detailing the argument.

"The gist of his discussion was, if you don't build the engine right, anything above it that you put your time and money in is a waste of your time because if you don't build this right, you're not getting into space," Hausman said.

Steven Siceloff

NASA's John F. Kennedy Space Center

Saturday, November 6, 2010

NASA EPOXI Flyby Reveals New Insights Into Comet Features

PASADENA, Calif. – NASA's EPOXI mission spacecraft successfully flew past comet Hartley 2 at 7 a.m. PDT (10 a.m. EDT) Thursday, Nov. 4. Scientists say initial images from the flyby provide new information about the comet's volume and material spewing from its surface.

"Early observations of the comet show that, for the first time, we may be able to connect activity to individual features on the nucleus," said EPOXI Principal Investigator Michael A'Hearn of the University of Maryland, College Park. "We certainly have our hands full. The images are full of great cometary data, and that's what we hoped for."

EPOXI is an extended mission that uses the already in-flight Deep Impact spacecraft. Its encounter phase with Hartley 2 began at 1 p.m. PDT (4 p.m. EDT) on Nov. 3, when the spacecraft began to point its two imagers at the comet's nucleus. Imaging of the nucleus began one hour later.

"The spacecraft has provided the most extensive observations of a comet in history," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at the agency's headquarters in Washington. "Scientists and engineers have successfully squeezed world-class science from a re-purposed spacecraft at a fraction of the cost to taxpayers of a new science project."

Images from the EPOXI mission reveal comet Hartley 2 to have 100 times less volume than comet Tempel 1, the first target of Deep Impact. More revelations about Hartley 2 are expected as analysis continues.

Initial estimates indicate the spacecraft was about 700 kilometers (435 miles) from the comet at the closest-approach point. That's almost the exact distance that was calculated by engineers in advance of the flyby.

"It is a testament to our team's skill that we nailed the flyby distance to a comet that likes to move around the sky so much," said Tim Larson, EPOXI project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "While it's great to see the images coming down, there is still work to be done. We have another three weeks of imaging during our outbound journey."

The name EPOXI is a combination of the names for the two extended mission components: the Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft has retained the name "Deep Impact." In 2005, Deep Impact successfully released an impactor into the path of comet Tempel 1.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, manages the EPOXI mission for NASA's Science Mission Directorate. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., in Boulder, Colo.

For more information about EPOXI, visit: http://www.nasa.gov/epoxi and http://epoxi.umd.edu/.

For information about NASA and agency programs, visit:

Dead Spacecraft Walking

This is a great story that speaks to the technological excellence and engineering creativity that NASA has owned for over 50 years.

NASA Science News, October 27, 2010
Dead Spacecraft Walking

A pair of NASA spacecraft that were supposed to be dead last year are instead flying to the Moon for a breakthrough mission in lunar orbit.
"Their real names are THEMIS P1 and P2, but I call them 'dead spacecraft walking,'" says Vassilis Angelopoulos of UCLA, principal investigator of the THEMIS mission. "Not long ago they appeared to be doomed, but now they are beginning an incredible new adventure."

The story begins in 2007 when NASA launched a fleet of five spacecraft into Earth's magnetosphere to study the physics of geomagnetic storms. Collectively, they were called THEMIS, short for "Time History of Events and Macroscale Interactions during Substorms." P1 and P2 were the outermost members of the quintet.

Working together, the probes quickly discovered a cornucopia of previously unknown phenomena such as colliding auroras, magnetic spacequakes, and plasma bullets shooting up and down Earth's magnetic tail. This has allowed researchers to solve several longstanding mysteries of the Northern Lights.

The mission was going splendidly, except for one thing: Occasionally, P1 and P2 would pass through the shadow of Earth. The solar powered spacecraft were designed to go without sunlight for as much as three hours at a time, so a small amount of shadowing was no problem. But as the mission wore on, their orbits evolved and by 2009 the pair was spending as much as 8 hours a day in the dark.

"The two spacecraft were running out of power and freezing to death," says Angelopoulos. "We had to do something to save them."

The team brainstormed a solution. Because the mission had gone so well, the spacecraft still had an ample supply of fuel--enough to go to the Moon. "We could do some great science from lunar orbit," he says. NASA approved the trip and in late 2009, P1 and P2 headed away from the shadows of Earth.

With a new destination, the mission needed a new name. The team selected ARTEMIS, the Greek goddess of the Moon. It also stands for "Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun."

The first big events of the ARTEMIS mission are underway now. On August 25, 2010, ARTEMIS-P1 reached the L2 Lagrange point on the far side of the Moon. Following close behind, ARTEMIS-P2 entered the opposite L1 Lagrange point on Oct. 22nd. Lagrange points are places where the gravity of Earth and Moon balance, creating a sort of gravitational parking spot for spacecraft.

"We're exploring the Earth-Moon Lagrange points for the first time," says Manfred Bester, Mission Operations Manager from the University of California at Berkeley, where the mission is operated. "No other spacecraft have orbited there."

Because they lie just outside Earth's magnetosphere, Lagrange points are excellent places to study the solar wind. Sensors onboard the ARTEMIS probes will have in situ access to solar wind streams and storm clouds as they approach our planet-a possible boon to space weather forecasters. Moreover, working from opposite Lagrange points, the two spacecraft will be able to measure solar wind turbulence on scales never sampled by previous missions.

"ARTEMIS is going to give us a fundamental new understanding of the solar wind," predicts David Sibeck, ARTEMIS project scientist at the Goddard Space Flight Center. "And that's just for starters."

ARTEMIS will also explore the Moon's plasma wake-a turbulent cavity carved out of the solar wind by the Moon itself, akin to the wake just behind a speedboat. Sibeck says "this is a giant natural laboratory filled with a whole zoo of plasma waves waiting to be discovered and studied."

Another target of the ARTEMIS mission is Earth's magnetotail. Like a wind sock at a breezy airport, Earth's magnetic field is elongated by the action of the solar wind, forming a tail that stretches to the orbit of the Moon and beyond. Once a month around the time of the full Moon, the ARTEMIS probes will follow the Moon through the magnetotail for in situ observations.

"We are particularly hoping to catch some magnetic reconnection events," says Sibeck. "These are explosions in Earth's magnetotail that mimic solar flares--albeit on a much smaller scale." ARTEMIS might even see giant 'plasmoids' accelerated by the explosions hitting the Moon during magnetic storms.

These far-out explorations may have down-to-Earth applications. Plasma waves and reconnection events pop up on Earth, e.g., in experimental fusion chambers. Fundamental discoveries by ARTEMIS could help advance research in the area of clean renewable energy.

After six months at the Lagrange points, ARTEMIS will move in closer to the Moon-at first only 100 km from the surface and eventually even less than that. From point-blank range, the spacecraft will look to see what the solar wind does to a rocky world when there's no magnetic field to protect it.

"Earth is protected from solar wind by the planetary magnetic field," explains Angelopolous. "The Moon, on the other hand, is utterly exposed. It has no global magnetism."

Studying how the solar wind electrifies, alters and erodes the Moon's surface could reveal valuable information for future explorers and give planetary scientists a hint of what's happening on other unmagnetized worlds around the solar system.

Orbiting the Moon is notoriously tricky, however, because of irregularities in the lunar gravitational field. Enormous concentrations of mass (mascons) hiding just below the surface tug on spacecraft in unexpected ways, causing them over time to veer out of orbit. ARTEMIS will mitigate this problem using highly elongated orbits ranging from tens of km to 18,000 km.

"We'll only be near the lunar surface for a brief time each orbit (accumulating a sizable dataset over the years)," explains Angelopoulos. "Most of the time we'll linger 18,000 km away where we can continue our studies of the solar wind at a safe distance."

The Dead Spacecraft Walking may have a long life ahead, after all.

Thursday, October 14, 2010

NASA Engineer Helps Chilean Miners

Clint Cragg is a hero, and he never thought he would be. Nor did he plan to be. But his name is on many lips in light of the rescue of the Chilean miners.

Clint Cragg is principal engineer with the NASA Engineering and Safety Center at Langley Research Center. When the cave-in occurred, two doctors and a psychologist from NASA traveled to Chile to offer advice and assistance because of their knowledge and experience of survival in harsh environments. Cragg went along to see if there was anything else that NASA could offer.

While in Chile, Cragg talked with engineers from the Chilean navy who were discussing and planning a design for a rescue vehicle. He offered assistance in determining the requirements for the vehicle. Cragg was only in Chile for three days. However, the engineers there contacted him by email to accept his offer of assistance.

Cragg relates, “I put together a team of engineers from almost every center around the agency. Over the course of three days we hammered out a 12 to 13 page list of requirements for the capsule and sent that to the Chilean Minister of Health.”

The team suggested about 75 design features. A sampling of the suggested requirements: an oxygen supply, including technology that would reduce friction as the vehicle was traveling up and down the drilled shaft, also that the vehicle be constructed such that a single miner could simply enter and secure himself.

“After we had sent the requirements, I got some communication from one of the Chilean navy commanders intimately involved in the design process of the capsule,” Cragg reported. “He told me that they had incorporated most of the suggestions we had provided to them.

“There are a couple of things I’ll remember most about this whole experience. One is the openness and graciousness of the Chilean people. I thought they were very supportive of our visit and very supportive of the things we recommended they ought to do.

“The other thing I’m taking away from this is our agency really has a lot of exceptional people. The 20 or so engineers who offered to drop everything and work with me for three days to put this requirements list together really exemplify the things that NASA stands for.”

Monday, October 4, 2010

Don't Let the Dream Die

After seven months of intense and confusing wrangling, the House followed (for the most part) the Senate and voted an authorization bill for NASA. I'm not here to offer opinion of the bill, nor of the political machinations which brought all this on. There is plenty of that on other blogs and sufficient in the news.

I'm here for only one reason. Whatever path NASA is compelled to take, please do not let the dream die. There has been a great deal of hostility and criticism piled on NASA in these last several months. Some of it is credible, most of it is not. I realize that a great many people don't have insight into the workings of NASA, nor the budget process, no the technical insight to grasp why NASA may have seemed slow in the past to produce a follow-on to shuttle. I'm not here to criticize them either.

My one and only desire is to implore, with all my strength and ability, because that seems to be the only way to get through all the impediments. Don't let the dream die. The dream of space flight and exploration. There are reasons aplenty to push outward from the earth. There are practical reasons, such as technology development. There are less pragmatic reasons, such as the human nature to explore the unknown. Also, there are so many other reasons which I haven't breathed. And anyone who truly wants to understand NASA and the reason for its being should assay to comprehend all the reasons. If an individual just doesn't get why any nation would spend billions on space exploration, then this person should work to see the overall picture, not just one image. Though I do understand that there are so many people who do not want to understand, nor be bothered with trying to.

That leaves the burden to push for NASA's continued presence in space to those of us who do get it...and want it and support it. That's what this is about. In a time of splintering because of differing motives and differing political views and differing objectives for the nation's space program, let those of us who do support space exploration come together in support for that objective and keep the dream from dying.

Go outside tonight and look up. Look at the thin crescent moon. Look at Jupiter and Venus shining brightly. See all the stars so far away, so unknown and beckoning. Check http://spaceflight.nasa.gov/realdata/sightings/cities/skywatch.cgi?country=United+States and watch for the bright light of the International Space Station speeding over your head. We are already a permanent presence in space. There are men and women up there living and working and increasing our knowledge of outer space and inner space...our space. Think about that. What does it mean to you? If it means nothing, then I challenge you to reconsider and visit www.nasa.gov to find out more about NASA and all it has done and continues to do. If the knowledge that people are living in space excites you, then spread the excitement. Let your representatives know how you feel. Take a friend outside and share your excitement. It can be very contagious. And that contagion is life for NASA. Spread it generously.

And don't let the dream die.

Monday, November 16, 2009

Time Names Ares One of Best Inventions of 2009


The Best Invention of the Year: NASA's Ares Rockets

Thursday, Nov. 12, 2009


Metal has no DNA; machines have no genes. But that doesn't mean they don't have pedigrees — ancestral lines every bit as elaborate as our own. That's surely the case with the Ares 1 rocket. The best and smartest and coolest thing built in 2009 — a machine that can launch human beings to cosmic destinations we'd never considered before — is the fruit of a very old family tree, one with branches grand, historic and even wicked.

There are a lot of reasons astronauts haven't moved beyond the harbor lights of low-Earth orbit in nearly 40 years, but one of them is that we haven't had the machines to take us anywhere else. The space shuttle is a flying truck: fine for the lunch-bucket work of hauling cargo a couple of hundred miles into space, but nothing more. In 2004, however, the U.S. committed itself to sending astronauts back to the moon and later to Mars, and for that, you need something new and nifty for them to fly. The answer is the Ares 1, which had its first unmanned flight on Oct. 28 and dazzled even the skeptics.

From a distance, the rocket is unprepossessing — a slender white stalk that looks almost as if it would twang in the Florida wind. But up close, it's huge: about 327 ft. (100 m) tall, or the biggest thing the U.S. has launched since the 363-ft. (111 m) Saturn V moon rockets of the early 1970s. Its first stage is a souped-up version of one of the shuttle's solid-fuel rockets; its top stage is a similarly muscled-up model of the Saturn's massive J2 engines.

If that general body plan doesn't exactly break ground, that's the point. NASA tried breaking ground with the shuttles and in doing so broke all the rules. Shuttle astronauts sit alongside the fuel — next to the exploding motor that claimed Challenger, beneath the chunks of falling foam that killed Columbia. And when you fly a spacecraft repeatedly as opposed to chucking it after a single use, there's a lot of wear to repair.

When NASA engineers gathered to plan the next generation of America's rockets, they thus decided to go back to the future — way back. The Saturn V was the brainchild of Wernher von Braun, the German scientist whose bright genius gave the U.S. its finest line of rockets — and whose dark genius gave Hitler the V2 missile that rained terror on London. Von Braun had, in turn, drawn insights from American rocket pioneer Robert Goddard. Goddard built on the work of 17th century artillery innovator Kazimierz Siemienowicz, a Pole.

The Ares 1 is a worthy descendant of their rockets and others, with lightweight composites, better engines and exponentially improved computers giving it more reliability and power. The Ares 1 will launch an Apollo-like spacecraft with four crew members — perhaps by 2015. Alongside it, NASA is developing the Brobdingnagian Ares V, a 380-ft. (116 m) behemoth intended to put such heavy equipment as a lunar lander in Earth orbit, where astronauts can link up with it before blasting away to the moon. Somewhere between the two rockets is the so-called Ares Lite — a heavy-lift hybrid that could carry both humans and cargo and is intended to be a design that engineers can have in their back pockets if the two-booster plan proves unaffordable.

The new rockets could take astronauts to some thrilling places. The biggest costs — and risks — associated with visiting other celestial bodies are from landing and taking off again. But suppose you don't land? An independent commission appointed by the White House to make recommendations for NASA's future recently returned its 154-page report and made strong arguments for bypassing the familiar boots-in-the-soil scenario in favor of a flexible path of flybys and orbits.

Under the new thinking, astronauts could barnstorm or circle the moon, Mars and Mars' twin moons, deploying probes to do their rock-collecting and experiments for them. They could similarly sample near-Earth objects like asteroids. They could also travel to what is known as the Lagrange points — a scattering of spots between Earth and the moon and Earth and the sun where the gravitational forces on the bodies are precisely balanced and spacecraft simply ... hang where they are. These would serve as ideal spots for deploying probes and conducting cosmic observations.

Troublingly for Ares partisans, the same commission that called for such creative uses for the new rockets also called into question how affordable they are, arguing that it might be better simply to modify boosters now used to carry satellites and put a capsule on top. Maybe — but there's the question of safety too. NASA designers say the Ares line will be 10 times as safe as the shuttle and two to three times as safe as competing boosters.

There's no way of knowing if those projections are too rosy, but if history teaches us anything, it's that the space program's grimmest chapters — the launchpad fires and shuttle disasters — unfold when policy planners lean too hard on engineers. The finest moments occur when the bureaucrats give the designers a clean sheet of drafting paper and let them dream. There's genius in knowing how to create a truly big invention — and there's wisdom in knowing how to recognize it and use it.

See pictures of the Ares rockets launching.

Wednesday, September 23, 2009

Someone had to say it

And Michael Griffin did.

He has the intelligence to cut through the bull, the boldness to push the bull aside, and the ability to effectively communicate his thoughts concisely and directly.

Here are his thoughts on the Augustine Commission's report. It's entertaining to see so many in the media call his letter sour grapes. That shows how little they understand one of the best administrator's that NASA had. A resource difficult to replace.

I stand aside and allow him to push aside the curtain...

From: "Michael D. Griffin" To: XXXXXXXXXX

1) It is clarifying to see a formal recognition by the Commission that, based upon budgetary considerations, "the human spaceflight program appears to be on an unsustainable trajectory". Given that the Constellation program was designed in accordance with the budget profile specified in 2005, yet has since suffered some $30 billion of reductions to the amount allocated to human lunar return (including almost $12 billion in just the last five fiscal years) this is an unsurprising conclusion, but one which provides the necessary grounding for all subsequent discussions.

2) Since NASA's budget as outlined in 2005 was hardly one of rampant growth (only a slight increase above inflation was projected even then), and since the Commission did not report any evidence of substandard execution of the Program of Record - Constellation - one wonders why the Commission failed to recommend as its favored option that of simply restoring the funding necessary to do the job that has, since 2005, been codified in two strongly bi-partisan Congressional Authorization Acts. Of all the options considered, this is the most straightforward, yet it was not recommended. The so-called "less constrained" options merely provide partial restoration of budget authority that was removed within just the last few years. The most obvious conclusion to be drawn from the Commission' report is this: put it back.

3) The continual reference to the supposedly planned cancellation and deorbiting of ISS in 2016 is a strawman, irrelevant to consideration of serious programmatic options. While it is certainly true that Bush Administration budgets did not show any funding for ISS past 2015, it was always quite clear that the decision to cancel or fund the ISS in 2016 and beyond was never within the purview of the Bush Administration to make. In the face of strong International Partner commitment to ISS and two decades of steadfast Congressional commitment to the development, assembly, and utilization of ISS, it has never been and is not now realistic to consider cancellation and deorbiting of ISS in 2015, or indeed on any particular date which can be known today. The fact that some $3+ billion per year will be required to sustain ISS operations past 2015 is, and has always been, a glaring omission in future budget projections. Sustained funding of the ISS as long as it continues to return value - certainly to 2020 and quite likely beyond - should have been established by the Commission as a non-negotiable point of departure for all other discussions. Failure to do so, when the implications of prematurely canceling ISS are well known to all, is disingenuous. The existence of future exploration programs cannot be traded against sustenance of the ISS on an "either-or" basis, as if the latter option was a realistic option. If the nation is to lay claim to a viable human spaceflight program, the requirement to sustain ISS while also developing new systems to go beyond low Earth orbit is the minimally necessary standard. If the nation can no longer meet this standard, then it should be so stated, in which case any further discussion of U.S. human exploration beyond LEO is moot for the next two decades.

4) Numerous options are presented which are not linked by common goals or a strategy to reach such goals. Instead, differing options are presented to reach differing goals, rendering it impossible to develop meaningful cost/schedule/performance/risk comparisons across them. These options possess vastly differing levels of maturity, yet are offered as if all were on an equally mature footing in regard to their level of technical, cost, schedule, and risk assessment. This is not the case.

5) "Independent" cost estimates for Constellation systems are cited. There is no acknowledgement that these are low-fidelity estimates developed over a matter of weeks, yet are offered as corrections to NASA's cost estimates, which have years of effort behind them. No mention is made of NASA's commitment to probabilistic budget estimation techniques for Constellation, at significantly higher cost-confidence levels than has been the case in the past. If the Commission believes that NASA is not properly estimating costs, or is misrepresenting the data it has amassed, it should document its specific concerns. Otherwise, the provenance of NASA's cost estimates should be accepted, as no evidence has been supplied to justify overturning them.

6) The preference for "commercial" options for cargo and, worse, crew delivery to low Earth orbit appears throughout the Summary, together with the statement that "it is an appropriate time to consider turning this transport service over to the commercial sector." What commercial sector? At present, the only clearly available "commercial" option is Ariane 5. Launching a redesigned Orion crew vehicle is a valid choice in the context of an international program if - and only if - the U.S. is willing to give up independent access to low Earth orbit, a decision imbued with enormous future consequences. With an appropriately enlightened USG policy there may one day be a domestic commercial space transportation sector, but it does not presently exist and will not exist in the near future; i.e., substantially prior to the likely completion dates for Ares-1/Orion, if they were properly funded. The existence of a prudently funded USG option for cargo/crew delivery to ISS is precisely the strategy which allows the USG to take reasonable risks to sponsor the development of a viable commercial space sector. The Commission acknowledges the "risk" associated with its recommendation, but is not clear about the nature of that risk. If no USG option to deliver cargo and crew to LEO is to be developed following the retirement of the Space Shuttle, the U.S. risks the failure to sustain and utilize a unique facility with a sunk cost of $55 billion on the U.S. side, and nearly $20 billion of international partner investment in addition. The Russian Soyuz and Progress systems, even if we are willing to pay whatever is required to use them in the interim, simply do not provide sufficient capability to utilize ISS as was intended, and in any case represent a single point failure in regard to such utilization. To hold the support and utilization of the ISS hostage to the emergence of a commercial space sector is not "risky", it is irresponsible.

7) The Commission is disingenuous when it claims that safety "is not discussed in extensive detail because any concepts falling short in human safety have simply been eliminated from consideration." Similarly, the Commission was "unconvinced that enough is known about any of the potential high-reliability launcher-plus-capsule systems to distinguish their levels of safety in a meaningful way." For the Commission to dismiss out of hand the extensive analytical work that has been done to assure that Constellation systems represent the safest reasonable approach in comparison to all other presently known systems is simply unacceptable. Work of high quality in the assessment of safety and reliability has been done, and useful discriminators between and among systems do exist, whether the Commission believes so or not. To this point, the Commission's report is confusing as regards the distinction between "reliability" and "safety", where the issue is discussed at all. The former is the only criterion of interest for unmanned systems; for manned systems, there is an important difference due to the existence of an abort system and the conditions under which that abort system can and must operate. Nowhere is this crucial distinction discussed.

8) "Technical problems" with Ares-1 are cited several times, without any acknowledgement that (a) knowledgeable observers in NASA would disagree strongly as to the severity of such problems, and (b) Constellation's "technical problems" are on display because actual work is being accomplished, whereas other options have no problems because no work is being done.

9) The recommendation in favor of the dual-launch "Ares-5 Lite" approach as the baseline for lunar missions is difficult to understand. It violates the CAIB recommendation (and many similar recommendations) to separate crew and cargo in whatever post-Shuttle human space transportation system is to be developed. Further, the dual-Ares-5 Lite mission architecture substantially increases the minimum cost for a single lunar mission as compared to the Ares-1/Ares-5 approach, a recommendation which is difficult to understand in an already difficult budgetary environment. Finally, the Ares-5 Lite is nearly as expensive to develop as the Ares-5, but offers significantly less payload to the moon when used -- as will be required -- in a one-way, single-launch, cargo-only mode. (The LEO payload difference of 140 mt for Ares-5 Lite and 160 mt for Ares-5 masks a much greater difference in their lunar payload capability.) All parties agree that a heavy-lift launcher is needed for any human space program beyond LEO. Because of the economies of scale inherent to the design of launch vehicles, such a vehicle should be designed to lift as large a payload as possible within the constraints of the facilities and infrastructure available to build and transport it. This provides the greatest marginal improvement in capability at the lowest marginal cost.

10) The use of "fuel depots" as recommended in the Summary appears to be a solution in search of a problem. It is difficult to understand how such an approach can offer an economically favorable alternative. The Ares-5 offers the lowest cost-per-pound for payload to orbit of any presently known heavy-lift launch vehicle design. The mass-specific cost of payload to orbit nearly always improves with increasing launch vehicle scale. The recommendation in favor of an architectural approach based upon the use of many smaller vehicles to resupply a fuel depot ignores this fact, as well as the fact that a fuel depot requires a presently non-existent technology - the ability to provide closed-cycle refrigeration to maintain cryogenic fuels in the necessary thermodynamic state in space. This technology is a holy grail of deep-space exploration, because it is necessary for both chemical- and nuclear-powered upper stages. To establish an architecture based upon a non-existent technology at the very beginning of beyond-LEO operations is unwise.

11) Finally, the Commission did not do that which would have been most valuable - rendering a clear-eyed, independent assessment of the progress and status of Constellation with respect to its ability to meet goals which have been established in two successive NASA Authorization Acts, followed by an assessment of what would be required to get and keep that program on track. Instead, the Commission sought to formulate new options for new programs, treating these options as if their level of maturity was comparable to that of the baseline upon which NASA has been working now for more than four years. This approach completely ignores the established body of law which has guided NASA's work for the last four years and which, until and unless that body of law is changed, must serve as the common reference standard for any proposed alternatives to Constellation as the program of record for the nation's existing human spaceflight program.