Let’s be fair about Russian engines

29 12 2014

The Motley Fool just posted an article about Orbital Sciences electing to replace the Soviet-designed and Soviet-built NK-33 engine on its Antares rocket with the Russian-built RD-181, an offshoot of the RD-180 engine currently in use on the Atlas V. The article then went on to speculate about this decision ultimately being a win for SpaceX, an American company that designs and builds its own engines for for its own rockets. I scrolled down to the comments section, which was my mistake, to see lots of people who clearly know nothing of rockets or aerospace engineering, but know they don’t like Russia, pissing on the RD-181.

In any engineering field, knee-jerk reactions are less tolerable than in other, less rigorous fields. When selecting an engine for a rocket, you have to look facts and statistics squarely in the eye and calmly make a logical, justifiable choice. The NK-33, RD-180, and RD-181 are all proven, powerful engines that meet the requirements for their rockets. The only American engine to outperform all Russian/Soviet engines in terms of thrust-to-weight ratio is the Merlin 1D, currently in service on the Falcon 9.

Whether Orbital thought they could get a better price on the RD-181 or SpaceX was not interested in selling its engines, I have no idea. The NK-33 is the second-most powerful LOx/kerosene engine in terms of TWR and the RD-181 is the third.

When the modified NK-33s (later renamed AJ-26) were installed on the Antares rocket, both engines had been taken apart, rebuilt, test, fired, and tested again. These were not some chunks of rust that Orbital got for a deal on the Russian black market. These were well engineered, tested, and vetted engines. Unfortunately, you cannot remove every bit of risk from a launch.

I don’t like what Russia has been doing to its neighbors, Ukraine in particular. I don’t like that they make so much money off oil and gas any more than we use lots of oil and gas. I think there were managerial oversights during the Shuttle-Mir program. I, like most Americans, have reasons to not completely trust Russia. However, feelings mean nothing when you are staring at specs and data and trying to make an engineering decision.

If you are an American and you want us to have better, more powerful, more efficient, and more reliable engines than the Russians, go out and build them. Otherwise, shut up about it and accept that Orbital made the best decisions they could and that’s all we can expect of anyone.





ULA’s future

13 08 2014

Earlier today, United Launch Alliance CEO and President Michael Gass abruptly retired immediately following what was surely a tense board meeting. Mr. Gass was presumably let go after sanctions by Russia left the future of ULA’s workhorse, the Atlas V, in question.

Atlas V (401) launches with LRO and LCROSS

Atlas V 401 launch

The ULA is a joint venture between Boeing and Lockheed to provide launch services. Their main customer is the US Federal government and the bulk of their flights are for the US Air Force and the National Reconnaissance Office. NASA’s Mars rovers were also launched by ULA rockets. ULA was formed to consolidate operations and control costs for government space missions. Unfortunately, this has resulted in an effective monopoly and costs for government-related launches have gone through the roof.

ULA relies on two main launchers, Delta IV and Atlas V. Both of these are expandable and flexible to accommodate different launch requirements. The first stage of the Atlas V relies on the RD-180 engine, which is imported from Russia and is a result of the Soviet Union’s efforts to build a Moon rocket in the 1960s. It is a direct descendant of the NK-33, which was featured on the N1.

Though ULA bought the designs and the rights to build an American version of the RD-180, they have not because it would cost billions of dollars and at least three years. It was simply easier and cheaper in the short term to buy the engines from Russia. With tensions between the United States and Russia over Russia’s attempted annexation of the Crimean Peninsula, the Russian government has made it as difficult as possible for ULA to buy these engines. Without any more engines coming in, ULA has enough for another three years of Atlas V flights.

Besides putting several American national security launches at the mercy of the Russian government, this is also likely to interfere with ULA’s participation NASA’s Commercial Crew program. Of the three candidate spacecraft, two of them, Boeing’s CST-100 and Sierra Nevada Corporation’s Dream Chaser, are expecting to use the Atlas V at around the same time the RD-180 stockpile dries up. (The third ship is SpaceX’s Dragon, which already makes use of the company’s Falcon 9 rocket.)


Delta IV Common Booster Cores

Delta IV Common Booster Cores being prepared for a Delta IV Heavy launch

With growing competition from new aerospace companies, SpaceX in particular, and a fleet of aging hardware, ULA needs to move fast to survive. They need cheaper, more capable launch vehicles with all major components (including engines) produced domestically. In the short term, plans should be made to sunset Atlas V after the existing stockpile of RD-180s is exhausted, but retain the Delta II and Delta IV series until a new vehicle can be put into service.

Russia's new Angara launch system

Four different configurations of Russia’s new Angara launch system

Delta IV’s use of Common Booster Cores (CBCs) is a clever idea and it should be retained. Russia’s upcoming Angara rocket family will eventually supplant Dnepr, Rokot, Proton, and Soyuz for most launch situations and will make use of its own version of the CBC. By manufacturing large quantities of smaller, identical stages and combining them as necessary, there is potential to drive costs down.

Both ULA systems use liquid oxygen as an oxidizer. The current Atlas V uses RP-1 and Delta IV uses liquid hydrogen. Other rockets, like Proton use hypergolic fuels, which are highly corrosive. There are advantages and disadvantages to every fuel combination and the best one to used would depend on the primary application of the rocket, as well as forthcoming technologies. The ideal fuel would depend on what sort of work ULA is doing in five years. If it’s small payloads, a solid-fuel rocket like the Minotaur would be appropriate. For the moment, Atlas V’s RP-1 first stage and LH2 Centaur upper stage are a very effective combination and would be ideal for medium-lift situations.


ULA went a long time without any meaningful competition and it will take some time for it to become competitive again. I am a big SpaceX fan and I hope that they will be allowed to fairly compete for Air Force contracts alongside ULA. That said, I wish ULA success and to compete with SpaceX so they can force each other to be better.


 

Videos





Why Russia is not our enemy in space

25 03 2014

I love space and I love learning more about spaceflight, especially when there are people doing the flying. I often get into discussions on the subject with people and the subject of being partners with Russia on the ISS invariably comes up. Most people seem horrified at the idea of America relying on Russian Soyuz spacecraft and rockets to get our astronauts to space and back. I’m not entirely comfortable with it, either, but it’s really not that bad.

CBC’s Janet Davison interviewed Canadian astronaut Chris Hadfield about working with Russians in low-Earth orbit. In the interview, he explained well why tensions between the West and Russia are not likely to interfere with ISS operations.

AST display at US National Air and Space Museum

ASTP display at US National Air and Space Museum

The first joint international mission in space was between the Soviet Union and the United States. Flown in 1975, the Apollo-Soyuz Test Project (ASTP) featured the docking of an Apollo CSM and a Soyuz spacecraft and laid the groundwork for future cooperation in space. It led to Americans visiting Mir and for a much larger international coalition coming together to build the International Space Station. Russia and the United States are both partners in this project and it could not go on without either one.

Space Shuttle Atlantis docked with Mir in 1995

Space Shuttle Atlantis docked with Mir in 1995

The Space Shuttles were retired after the programs 135th mission, STS-135. The Space Shuttle program extended from 1981 to 2011 and its duration is only exceeded by the Soyuz program, which began in 1967 and is still in operation today. The key difference is that the Shuttles were reused and the Soyuz is a single-use spacecraft. After 30 years and two lost orbiters, it was simply too expensive, difficult, and dangerous for NASA to continue the program. Next-generation spacecraft had been on the drawing boards for years and it seemed the time to give them a chance. Orion, Dragon, CST-100, and Dream Chaser are all beginning to come together to reduce the cost of going to space while allowing us to go much farther than we ever have before. There are some related videos for these vehicles below.

Space Shuttle Endeavour docked with ISS

Space Shuttle Endeavour docked with ISS in 2010

American astronauts and Russian cosmonauts are all professionals and know what their jobs are. They know that there is a time and place for politics and that neither the ISS, inside a spacecraft, nor while training are it. I wish that we had had a successor in place and ready to go before the Space Shuttles were retired. However, it is important to keep in mind that there was a period of six years between the last Apollo flight in 1975 and the first Space Shuttle flight in 1981. The Shuttles were grounded in 2011 and most of these new spacecraft are tracking for operational status in 2017. In just a few years, America will have the ability to launch its own astronauts and we can stop buying Soyuz seats from the Russians. Until then, we are still major partners on the ISS and will continue to be until at least 2024. Until then, we have to be patient. Space travel is a difficult, time-consuming thing.


Orion:

Dragon:

Dream Chaser:





Tailoring eTextbook content to different regions

2 10 2013

Recently, the Los Angeles Unified School District (LAUSD) got some press for its introduction of iPads into their high school classrooms. They have instituted a program to loan iPads to all of their high school students to aid in their studies. Inevitably, the subject of electronic textbooks came up in this discussion.

Electronic textbooks have enormous potential to aid in education. Of course, as is the case with any technology, there are drawbacks.

An electronic text can be updated constantly in the background. As current events unfold, they can be added to textbooks and classroom discussion and thought can be centered around those events. There is no way to do this with paper textbooks without printing a whole new edition and convincing school districts across the entire country to invest in them.

jesusondinoIt is also possible for a school district to get a copy of a textbook from a publisher and tailor it for their schools and students. This could solve much of the turmoil caused be folks like those on the Texas Board of Education. Texas purchases many textbooks and publishers do not want to be burdened with making two versions of a 500-page book. Because of this, there is a possibility that future American biology textbooks will include Creationism, euphemistically called “Intelligent Design.”

This is where we get into dangerous territory. In theory, it would be possible for states with more religious legislators and officials to approve science books with Bible verses in them and the other states to put actual science into their science books. We would risk further bifurcating America by producing two groups of citizens, those who learn about evolution and actual science and those who do not understand science and mistrust it.

My first instinct was to say, “So what? Let those backward states have their pseudoscience. Once they get passed up by the other states, they will see the error of their ways.” Unfortunately, it would not work this way. For things like science, we must have everyone learning the same basic principles and facts. To do otherwise would be risking a dangerous division in our country.

Obviously, this is not a problem that is going to be solved overnight. Maybe it will not be as bad as I think it will be. Hopefully, it will not. That said, this is probably going to come up in one form or another.





4 03 2013

Originally posted on Open Mind:

Anybody can do it.

Fake “skeptics” of global warming do it all the time. One of the latest and most extreme — this one is a real doozy — comes from John Coleman. Of course it’s regurgitated by Anthony Watts.

View original 981 more words





Don’t want your info hacked? Don’t put it online.

4 03 2013

The free and paid note-taking application Evernote was recently hacked, forcing the company to reset passwords for many users, including myself, and to require them to reset their passwords on all of their computers and devices before they could continue to use it. This has caused a small stir and some have chosen to enumerate some of its security failings.

Evernote iconI use Evernote every day and I love it. It is a great way to keep notes and documents synced between my computers and to see them on my iPhone. However, I still acknowledge that this is a web-based service because all of my notes live on a server somewhere else, a server that I neither own nor maintain. Since it is on the web, I approach it with a fair amount of caution. I use the same rule that I use for all my other web-based accounts on Facebook, Twitter, GitHub, Flickr, et cetera. I do not put anything into Evernote that I would not be fine with the whole world seeing. Everything else, I keep on my own drive(s).

The Evernote team certainly has their share of blame, with their lax attitude toward security and even encouraging users to put their tax documents on Evernote. However, the users have their share of blame. If you are willing to put any of your tax documents on a non-governmental web site, you are essentially accepting the consequences of sharing very sensitive documents with the whole world.

It may sound harsh, but there it is. If you do not want to see Evernote leak your personal information, do not give Evernote that information. It will not make it into someone else’s hands unless you give that information to them.





Hubble and Doppler Shift

30 01 2013

Edwin Hubble, after whom the Hubble Space Telescope is named, was an astronomer in the early twentieth century. At that time, modern cosmology was still in its infancy and there were many assumptions and false conclusions about the universe.

Probably the most noteworthy assumption of that time was the presence of “island universes.” For years, astronomers had observed strange, rounded clouds in the distant sky. They had assumed that these were other universes, isolated by nothingness. Today, we now know that these are galaxies, collections of billions or even trillions of individual stars, gravitationally bound to each other.

Another assumption was that the universe was static. This is called the “steady-state” model. In this model, all stars and other large objects were fixed in place and the energy and mass densities of the Universe could not change. In this case the energy density is the amount of energy contained within a certain amount of a space, a cubic meter, for example. The same goes for mass density. The Universe’s size was fixed and all matter and energy had to be conserved. Therefore, the density of the Universe remained constant.

Doppler shift

Another basic subject that should be covered here is that of Doppler shift. Doppler shift is a phenomenon that can be observed in every day life. A common example is that of an ambulance driving by with its siren on. As it approaches the listener, the siren’s pitch sounds slightly higher than normal. As it leaves the listener, the siren’s pitch sounds lower. This is because the sound waves are being accelerated by the motion of the ambulance. This causes the crests of the sound waves to become compressed as the approach the listener and expand as the wave source moves away.

In astronomy, the is typically known as “redshift” for receding wave sources and “blueshift” for approaching wave sources. This phenomenon became critical to Hubble’s research in 1929.

Discovery of galaxies

Hubble’s first discovery in 1919 radically altered our understanding of the universe. By identifying several characteristic of certain nebulae, including Andromeda (M31), he realized that these were not the island universes that everyone had assumed them to be. They were, in fact, other galaxies like our own and were much more distant than previously thought. Naturally, there were those in the scientific community who resisted the notion at first, but they were eventually compelled by the evidence.

Redshift of the galaxies

This discovery paved the way for another, equally important, realization that came ten years later. Hubble observed that nearly all the other galaxies were receding from our own. Working from the assumption that the galaxies most similar to ours should have similar types of stars in similar proportions, Hubble observed that most of these galaxies were redshifted, indicating that they were moving away from us with extreme velocity.

Expansion of the Universe

Furthermore, the farther the galaxies were, the greater the redshift. This means that the farther a galaxy is from us, the greater its speed away from us is. This can be represented by the following equation, called Hubble’s Law.

v = H0D

v is the speed with which a galaxy is moving away from us.
D is our distance from that galaxy.
H00 is the Hubble constant, which describes the relationship between the two variables.

The Hubble constant has been changed and updated as new cosmological observations and measurements have been made over the past 90 years. As of research performed with the Chandra X-Ray Observatory in 2006, one current estimate places the current Hubble constant at 77 kilometers per second per megaparsec (77 [km•s-1]•Mpsc-1). That is, that, in one dimension, 77 kilometers of space is being added to each linear megaparsec of space every second. This gives us a rate of expansion of the universe.

Space is expanding at every point in the universe but the expansion is only observable at distances where it can overcome the four basic forces, including gravity.

Hubble sphere

Since Hubble’s law states that recessional velocity will increase with relative distance, this would mean that, eventually, the recessional velocity would equal the speed of light. We could then rearrange the law to find what distance is required for this to happen.

If v = c = H0D,
then D = c/H0.

In this case D could be represented by RHS, the radius of the Hubble sphere, or Hubble volume. The Hubble sphere is a spherical region around an observer that defines the boundary of the observable universe. At this point, the light from distant galaxies becomes so redshifted that we can no longer observe it because they are receding at a rate of speed faster than the light they emit.

We have no way of observing anything beyond the Hubble sphere because the distances are so vast that light is not fast enough to overcome the expansion of the Universe to reach us. There is likely more universe beyond this sphere, but we simply cannot see it.

When we run the numbers, we find RHS to be approximately 13.9 billion lightyears. Since the universe is roughly 13.7 billion years old, any light we see at the edge of the Hubble sphere has been traveling toward us almost as long as the Universe has allowed light to travel.

The difference between the age of the Universe and the size of the Hubble radius can be explained by taking into account the acceleration of the Universe’s expansion. The Hubble constant is actually variable and is increasing slowly.


All of this forms the backbone of modern cosmology. Without Hubble or the work he and his collaborators did, it is likely that cosmology would not be where it is today.








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