It's not rocket science

Image Credit: SpaceX

On Saturday night I was mindlessly surfing the web, waiting for some clothes to dry before I went to bed. I visited Phil Plait's Bad Astronomy blog, and he had a post with a link to watch a live webcast of SpaceX's first commercial launch of its Falcon 1 rocket.

First, a little background. Until recently, all large rocket launches in the U.S. have been run by NASA. NASA contracts private companies, such as Lockheed and Boeing, to build the Atlas and Delta rockets used for most launches, but NASA runs the show.

Recently, there has been a push by industry and the public to encourage private (by which I mean non-governmental) corporations to build and launch rockets capable of carrying satellites and people into space. The thought is that a private company can build a reliable, functional rocket with costs far lower than NASA's going rate. Competitions such as the Ansari X Prize are spurring development.

One of the first companies to try and go commercial is Space Exploration Technologies, or SpaceX. They have developed the Falcon rocket family that is supposedly capable of launching both small and large satellites into Earth orbit. They've attempted three launches so far. The first demonstration flight failed shortly after launch because of a bad bolt on the engine. The second demonstration flight almost worked, but failed to achieve orbit when fuel sloshing in the tanks caused the engine to shut down early. But they solved those problems, and pressed ahead.

Saturday's launch was their first commercial launch, and carried a handful of small satellites. Unfortunately, the launch failed when the first stage failed to separate from the second stage. In spite of the failure, SpaceX has vowed to carry on.

I don't know much about the SpaceX company, nor any of the other companies working on private space vehicles (like Virgin Galactic). And I know nothing about their rocket designs, and next-to-nothing about overall rocketry. I'm an astronomer, not an aerospace engineer. So, I don't have a good opinion on why the failure may have happened, whether SpaceX has a good or poor rocket design, and other such topics. But I do know that getting into space is very hard. Earth's gravity is pretty strong, our atmosphere exerts significant pressure and turbulence on rockets, and any rocket has so much fuel, it is essentially a flying bomb. Rocketry is a tricky business; there's a reason our language uses "rocket science" as a metaphor for ridiculously complex endeavors.

As new companies start and try to get into space, there will be failures, and likely multiple failures by any given company. Money will be lost to seemingly minor problems (like a rusty bolt); worse will be when lives are lost in flight (and that will happen). I don't know if private space flight will be economically feasible in the near term (I'm not an economist, either). I do find it exciting that there are people willing to try, willing to risk money and lives on ventures that may or may not succeed in the short term. In the long term, I think the outlook is good, as people learn from their experience and as technology continues to improve. But whether private space flight becomes common in ten years or fifty years, I don't know.

39 years ago today...

Image Credit: NASA

39 years ago, humankind took its first tentative steps into the cosmos when astronauts Neil Armstrong and Edwin "Buzz" Aldrin walked on the surface of the Moon as part of the Apollo 11 mission. (Their moonwalk, while only 2.5 hours long, started about 11pm EDT on July 20 and finished in the early morning of July 21, so there is some ambiguity in the "date" of the moonwalk. But why not celebrate this amazing accomplishment over two days, instead of just one?)

At the end of the Apollo Moon program in December, 1972 (a full year before I was born), few people suspected that it would be nearly 50 years before we returned to the moon (and it could be longer than that, if the Orion project is significantly delayed). To some people, this is a travesty. Other people wonder why we are even considering going back.

I think it is in our nature to explore. From our early Homo sapien ancestors leaving the African continent to colonize new lands, to seafaring peoples of many nations and races that sailed the vast and unfriendly seas, to the astronauts/cosmonauts/taikonauts who risk their lives to sail the vacuum of space, the unknown seems to draw us onward. So, I suspect that it is just a matter of time before we humans are crawling across the face of Mars, and perhaps even considering one-way flights to explore new worlds around other stars. But this "time" may be hundreds or thousands of years from now, and there are many other challenges facing us right here on our home planet. So I think we can afford to be patient, as long as we don't take our eyes off the ultimate goal.

Sp, if you look out late this evening to see a big yellow moon rising, remember that we were there just 39 short years ago.

When We Left Earth

Image Credit: NASA

Last night I watched the first two hours of the Discovery Channel's new NASA documentary, "When We Left Earth," a high-definition (and somewhat starry-eyed) look at NASA's first 50 years of manned spaceflight. Last night covered the Mercury and Gemini programs; next week will cover the Apollo moon exploration program, and in two weeks they'll cover the space shuttle. I thought it was a good documentary, and somewhat timely, as our first astronauts are aging all to quickly, and everyone my age and younger was born after the last moon landing. Alas, I don't have high-definition cable channels (I'm too cheap), so I missed the full impact of the program.

If you missed the program, I'm sure there will be re-runs; if you don't get the Discovery Channel, the DVD is already on sale (and probably available for rental).

It is easy to forget how little we knew about space just 50 years ago (Would the astronauts be able to swallow in space? Would Evel Knievel had been a better astronaut than Niel Armstrong?) and easy to forget how dangerous spaceflight really was and remains. And, as NASA prepares to send humans back to the moon, these are lessons we need to remember.

The end of a heroic spacecraft

Image Credit: NASA / JPL

The ancient Greek epic "The Odyssey" follows the adventures of Odysseus (known in Latin as Ulysses), who wanders the Mediterranian for ten years after the Trojan War, trying to get home to his wife and son. Today, it was announced that the modern Ulysses, a spacecraft studying the sun, will soon fall silent and be doomed to wander the Solar System for aeons to come.

Ulysses is a space probe studying the sun. It is unique in that it used Jupiter's gravity to get into an orbit that goes over the north and south poles of the sun. Without a little muscle from Jupiter, it isn't possible to launch a spacecraft into such an orbit -- all of our other solar probes orbit the sun at its equator, just as the Earth and all the planets do.

Ulysses was launched by the space shuttle Discovery in 1990, and after an 18-month trip to Jupiter, began its mission. It takes Ulysses 6 years to orbit the sun once, and it is most of the way through its third trip around the sun. Since the sun goes through a cycle of activity every 11 years, Ulysses has seen one and a half complete solar cycles.

The Ulysses mission was designed not to take pictures of the sun (we can do that from Earth!), but to study the sun's radiation and wind and magnetic fields from vantage points that the Earth can never see. Ulysses has studied how the sun's wind and magnetic field vary from the equator to the poles, information we could only guess at before. We've learned that the solar wind (a stream of particles coming out of the sun) is much faster near the sun's poles, moving along at over 450 miles per second! Here at the sun's equator, the wind blows at a much slower 200 miles per second. Ulysses also found that the sun's magnetic field is not much stronger near the poles than at the equator; a simple magnetic field would be twice as strong at the poles. This tells us that the sun's magnetic field is quite complicated. And, among many other discoveries, Ulysses found that the sun's magnetic field is very good at protecting us from cosmic rays, powerful radiation from the Galaxy and beyond. no matter what direction they are coming from.

Is there any saving Ulysses? No. Ulysses is powered by a radioactive power plant -- although the spacecraft is studying the sun, it is too far away from the sun for solar panels to work very well. In the power plant, radioactive fuel decays, creating heat that is converted to electricity. But as the fuel decays, the energy released steadily drops. Within the next month or two, the energy released will drop below the levels needed to keep the spacecraft pointed at the Earth.

So, although Odysseus was able to find his way back home after 20 years abroad, the Ulysses spacecraft will never get to come home. It will soon fall silent, continuing to orbit the sun for ages to come.

My congratulations to the Ulysses team on a long and successful mission!

NASA's rough week

Image Credit: NASA

This week marks the anniversary of the three worst accidents in NASA's history.

• January 27, 1967 Gus Grissom, Edward White and Roger Chaffee were killed in a launch pad fire during a training mission for the Apollo spacecraft. The fire was ignited by an electrical spark that ignited the pure-oxygen atmosphere of the Apollo capsule.
• January 28, 1986 Greg Jarvis, Christa McAuliffe, Ronald McNair, Ellison Onizuka, Judith Resnik, Michael J. Smith, and Dick Scobee perished when the space shuttle Challenger exploded 73 seconds after liftoff. The explosion was caused by a combination of bitterly cold weather and poor design of joints in the shuttle's solid rocket boosters.
• February 1, 2003 Rick D. Husband, William McCool, Michael P. Anderson, David M. Brown, Kalpana Chawla, Laurel B. Clark, and Ilan Ramon died when the space shuttle Columbia broke apart during re-entry. A piece of foam fell of the external fuel tank during liftoff and hit the shuttle's wing, creating a hole that allowed hot gases to enter and destroy the craft.

It is important to remember these people and accidents. These men and women willingly put their lives at risk to explore space, bravery that deserves recognition. But also, each of these accidents may have been preventable. A string of human errors and cultural issues led to each accident. These errors are much easier to see in retrospect than they were ahead of time, and so we should be careful in assigning blame to freely. Yet we can and must learn from these mistakes to protect future lives; to ignore these lessons would be an unforgiveable failure.

Finally, we should all recognize that more lives will be lost in the future. Space travel is extraordinarily dangerous. As private companies also begin to open space to civilians, we must accept that there will be accidents and lives lost, and most of these will probably be due to human error. Let's just hope that those errors are due to exploration and humankind's pushing of the envelope, and not due to our failure to learn from our history.

Hubble, here we come!

Tonight, if all goes well, the space shuttle Atlantis will launch on a visit to the International Space Station. Since the last shuttle launch, NASA's suffered through a series of bizarre events, including a tabloid-worthy love triangle, a hail storm resulting in an ugly-looking fuel tank, and a train carrying booster parts that derailed twice on its way across the country. With a successful and safe mission, hopefully NASA can put these odd events behind it.

In even better news (in my humble opinion), NASA also announced a launch date of September 10, 2008, for the next and final Hubble Telescope repair mission. Servicing Mission 4 (which is actually the fifth repair mission -- typical government counting, since Servicing Mission 3 was actually two visits) will install two new cameras, repair one existing camera (hopefully), replace the rechargeable batteries, replace broken gyroscopes, add new pointing sensors, and repair some insulation and other minor damage.

Personally, I question the usefulness of the International Space Station. It's horrendously expensive, and hasn't been able to do the promised science because of budget cutbacks. But we've agreed to build it, and we might as well use it (if we can find useful things to do). And, each passing shuttle launch brings us closer to both the Hubble repair and the end of the space shuttle program.

So, if you haven't watched a shuttle launch in a while, why not take some time to watch? Launch is scheduled for 7:38pm EDT. If you don't have access to cable TV, you can always watch NASA TV online. The launch has to happen in a 10 minute time frame for the shuttle to be able to meet the space station; otherwise, they'll have to try again another day.

To err is human

Image credit: NASA/JPL-Caltech But what should we think when human errors doom a spacecraft?

On Friday, NASA issued the final report on last November's loss of the Mars Global Surveyor spacecraft. The probe had been studying Mars for seven and a half years, almost four times longer than its planned lifetime of two years, when it fell silent.

NASA's report finds that a series of software errors (human programming errors) led to the Mars Global Surveyor's loss. If it hadn't been for these errors, MGS would probably still be working just fine! Yet I don't think it is right to get very upset about these mistakes. The mission was only designed for two years. Software updates are going to be necessary beyond that. Some electronics are damaged by radiation, so workarounds need to be devised. Also, as robotic spacecraft get older, mission planners allow for riskier operations, if such risks will net us science that cannot be done otherwise. Again, new software is needed to allow for those operations. And eventually some bugs are going to slip through. Most importantly, though, no human lives were endangered. Human errors are often the cause of death of spacecraft. In many cases, the spacecraft have far exceeded their lifetimes, and the current programmers were not even out of school when the spacecraft was launched. An example of this is the ROSAT X-ray telescope, which operated from 1990 to 1999. Its mission ended when, down to one gyroscope (which made pointing very hard), it was accidentally commanded to slew the camera over the sun.

Other times, human errors are less forgivable, because they occur before a spacecraft has completed its mission (or even started). These errors should have been caught, as the early parts of missions are thoroughly scripted and tested time and time again. Errors in this case include the losses of the Mars Climate Orbiter when it tried to go into orbit around Mars, which happened when NASA was using standard metric units (kilograms, kilometers, etc.) to run the spacecraft, but the spacecraft's builder, Lockheed Martin, used imperial units (pounds, inches, etc.), and nobody caught the mismatch. The Mars Polar Lander was lost when it was landing on Mars because software told the engine it had landed when it really was tens of feet above the surface and just extending its landing gear. Existing checks should have caught both of these errors before the spacecraft were even launched; instead, hundreds of millions of dollars were lost.

NASA is hoping to learn from the mistakes that doomed the Mars Global Surveyor in order to prevent such errors in the future. My guess is that human error will result in the loss of more spacecraft, but if we can learn from these mistakes, perhaps we can eke out more science from each robot before it is lost.