Asteroids and “blind luck”

[This article is taken from the April 28 issue of the RocketSciRick Update.]

Evidence has been increasing that the Earth has been pelted by asteroids more frequently that originally thought. In February 2013, an asteroid exploded over Chelyabinsk, Russia, injurying over 1,000 people – an event thought to happen roughly every 100 to 200 years. Then in November, scientists raised the estimate to once every decade or so. Finally, a few days ago, evidence from the Nuclear Test Ban Treaty Organization was presented of major detonations in the atmosphere. Except they weren’t from nuclear explosions; the network had detected airbursts of asteroids in the atmosphere.

According to the B612 Foundation 26 asteroid explosions have been detected since 2001. These ranged from 1 to 600 kilotons of TNT equivalent. For comparison, the explosion on Hiroshima was 15 kilotons. The 2013 explosion over Chelyabinsk was rated at 500 kilotons. The 1908 explosion of Tunguska, in Siberia, was in the range of megatons.

Ed Lu, a former astronaut and CEO of the B612 Foundation, said that “while most large asteroids with the potential to destroy an entire country or continent have been detected, less than 10,000 of the more than a million dangerous asteroids with the potential to destroy an entire major metropolitan area have been found by all existing space or terrestrially-operated observatories.”

“Because we don’t know where or when the next major impact will occur,” he said, “the only thing preventing a catastrophe from a ‘city-killer’ sized asteroid has been blind luck.”

The B612 Foundation has embarked on the Sentinel space telescope project to improve the detection of asteroids. Scheduled for launch in 2018, it expected to uncover 90 percent of asteroids larger than 140 meters across entering the Earth’s region of the solar system. It will also detect many as small as 30 meters across. The Chelyabinsk asteroid was 20 meters across and weighed 13,000 metric tons.

Jet Propulsion Laboratory has been building a catalog of asteroid impacts that may occur during the next century. Known as the Sentry Risk Table, it classifies asteroids by impact probabilities and likely size of the explosion, and provides possible impact dates. At the moment, no major explosions with any significant probability are on the list of 460+ objects. Then again, Chelyabinsk was not on the list. (But that was only 20 meters across.)

More info:
* B612 Foundation: https://b612foundation.org/
* Impacts since 2001 visualization: http://vimeo.com/92478179
* JPL Sentry Risk Table: http://neo.jpl.nasa.gov/risks/

What’s that e-journal thing?

Oh that. You’re referring to the RocketSciRick Update.  First, here’s what the Update says about itself:

The RocketSciRick Update is an experimental e-journal devoted to topics in aerospace sciences and engineering. It is currently produced by a one-person writing/editing staff in his not-so-spare time. Often, the recent news itself is summarized from current sources. But the back story behind the main story is also added to provide the context for what made the story what it is now. References are provided for the reader who wants to seek more information.

It is, in fact, an experimental journal distributed by e-mail.  Originally, I had no intention of doing such a journal myself.  I’ve been reasonably content to put sporadic updates on this website as the need arises.  However, a couple of the organizations that I deal with had needs related to e-mail campaigns to reach their members and other interested parties. Those needs are as yet unresolved.  Some suggestions had been made; I decided to explore one of them in more detail.  For lack of a better title, and since I believe in having a backing website for more information, the title became the RocketSciRick Update.

The needs that arose relate to aerospace-related organizations in Silicon Valley.  As a result, much of the focus of the Update is on stories of local interest.  In the current issue:

  • The B612 Foundation, which studies defense against a major asteroid impact, is located in the San Francisco Bay area.  Aside from them, there are a lot of people in the Bay area who are interested planetary defense or mining of asteroids.
  • KickSat, while started at Cornell University, has been worked on in part at NASA Ames. In fact, during his time at Ames, project lead Zac Manchester spoke about the project at a local technical meeting of the Silicon Valley Space Center and the AIAA San Francisco Section.  His funding of the project through KickStarter inspired others in the Bay area to follow suit.  As noted in the current issue, a couple of them have been launched into orbit.

The “SV Aerospace Calendar” which appears in the Update started up as a separate effort.  Some of us had discussed the desire to build a common calendar of events organized by the various local aerospace sciences and engineering groups.  In some quarters, it had actually turned into a sore point of lack of coordination.  I began another prototyping effort using Google Calendar, and host a display of it on this website.  The downside: certain security-conscious companies do not allow Google apps through their firewalls.  As a result, they can’t see the calendar.  When the Update started, it made sense to pull from that calendar and put into the Update content.

What is my impression of the process so far?

I’ve only partly explored the tools provided by the mail distributor, MailChimp.  There are things I’d like a system to do for me automatically, and I haven’t discovered them yet (e.g., TOC generation, proper paragraph tagging or styling).  They may be buried in there and simply need more time to investigate.  Given that MailChimp is a commercial mass mailing tool, it is subject to CAN-SPAM laws.  People who have opted out from their list cannot receive the Update.  This is true of competing services like Constant Contact.

Given everything else I do, I try to constrain the amount of time I spend doing writing, research, and editing for the Update; this experimental journal was not intended to be the definitive word on the subjects of interest, but a summary and pointer to additional sources.  Alas, the research and editing that I do has been fairly intense, almost as if I were assigned to the city desk of a newsroom.  It is an exhausting process… and probably not how I imagined spending my weekends.

And so far, the Update has no revenue and includes no advertising. If it is supposed to stay alive, it doesn’t have a very good business model.

For me, it serves as a learning process in understanding the state of the art of commercial tools for mass mail distribution.  For the local aerospace entrepreneurial community and friends, hopefully it informs them on developments of interest.  In essence, we are experimenting with what is the best way to keep such a diverse community informed, and in effect, how to nurture and grow it. If we can find a better way to do this through the Silicon Valley Space Center (SVSC) or the AIAA San Francisco Section (AIAA SF), then I will probably back off and let them run with it.  As those changes happen, I will announce them in the Update.  Readers of this website will undoubtedly find out about this as well.

–Rick, your resident Silicon Valley space journalist

SpaceX CRS-3 and re-light after MECO

In spite of thundershowers just hours before, a SpaceX Falcon 9 rocket carrying a Dragon spacecraft launched on time at 3:25:21 pm EDT on Friday, April 18, and headed for rendezvous with the International Space Station (ISS). The rendezvous dictated the length of the launch window:  1 second. In essence, any delay would have meant scrubbing the launch for the day. The launch was flawless.

SpaceX-CRS-3_Falcon_9_liftoff
Launch of Falcon 9 on SpaceX CRS-3 mission to ISS. April 19, 2014. (Image source: SpaceX)

For NASA, this is the third SpaceX Commercial Resupply mission (SpaceX CRS-3). It is one of 12 that NASA has contracted SpaceX to perform. These launches are conducted from Cape Canaveral, FL. The other CRS provider is Orbital Sciences, which launches its rockets from Wallops Island, VA, about 100 miles SE of Washington, DC.

This Dragon spacecraft had been heavily upgraded with new avionics and power so that it could accommodate new biological payloads to be sent to the ISS. A few hours before launch, under severe weather conditions, the SpaceX crew loaded the last of the time-sensitive payloads into the Falcon 9.  The whole assembly was then stood erect and the rocket loaded with propellant. The countdown was uneventful. The only concern was the weather, which amazingly was beginning to cooperate.

Following main engine cut-of (MECO) at 2:45 (m:ss) into the flight, the first stage was cast off, and the second stage took over the mission. But sometime later, the first stage came back to life. The stage turned around and the engine (well, at least one of the nine) was re-lit, cutting short the trajectory taking it far into the Atlantic. With most of the horizontal speed burnt off, the stage now fell into re-entry, subjected to plasma flow that does bad things to most materials. But after re-entry, some number of engines were lit again, slowing its descent further, and allowing landing legs to deploy about 10 seconds before hitting the water. Some 8 seconds after hitting the water, the on-board computers finally stopped transmitting when the stage went horizontal.

Meahwhile, back in space, the Dragon is due to dock with the ISS on Easter Sunday. The biologicals include a Vegetable Production System (VEGGIE), capable of producing salad-type vegetables in space; and the T-Cell Activation in Aging experiment, probing the cause of a depression in the human immune system in microgravity.  It also carries a laser communication experiment and 5 CubeSats for later deployment.

Unobtainium and investment

In my last post about “Requirements gone wild” (April 11), I mentioned the mythical material “unobtainium”, a notion that sometimes doesn’t sit well with people. This time, I’m going to do a reality check.

People sometimes seem to think that rocket science represents the pinnacle of human creativity. Watching a rocket launch is awe-inspiring. It is taken as evidence that anything the mind can imagine, human creativity can make real. I’m convinced that people who say that are really trying to say is that the human spirit, along with persistence, can accomplish anything; within a lot of human activity, that may be true.  But I’ve seen this used as a defense that some day we will have warp drive… just because we can imagine it today.  In the broader spectrum of how nature really behaves, this doesn’t hold up.

Fundamentally, science and engineering are about discovering and harnessing the laws of nature. We believe that the world is governed by a self-consistent set of laws of behavior.  We try to discover those laws, and sometimes we draw the wrong conclusions.  Nevertheless, we believe that nature itself is self-consistent in its behavior.  We can improve our understanding, but we cannot demand that nature contradict itself.  (Well, we can demand, but it won’t do any good.)

How well we understand those laws of nature is evident in the types of engineering we now engage in.  Sending a rocket to the Moon or detonating a nuclear device are both extremely dependent on our understanding those laws. Sometimes in engineering development, we don’t really know the answer.  So we have to do experiments to ask nature how it behaves under certain circumstances.  If we like the answer, we incorporate it into our design.  If we don’t, we go back to the drawing board.

“Unobtainium” is a code word for material that borders on violating the laws of physics.  In truth, we may not know how to create the material today.  It may cost us a couple of decades of major sweat to figure it out.  (I’m still waiting on nanotubes for digital circuitry with zero internal resistance.)  If it is possible at all, turning unobtainium into the obtainable takes non-trivial resources.  Sometimes, those resources are very expensive.If you are bringing VCs, angels, or other investors to the table, then what may be unique about your plan is how you convince yourself and investors that unobtainium really isn’t.  The business plan in part amounts to how you can prove it.  On the other hand, if investors smell unaddressed unobtainium (also known as “hand-waving”) in your plan, you can expect them to walk away.

I know.  I’m such a spoil-sport. :-/

As for warp drive, the notion is in fact being investigated, but as a possible extension of the current laws of physics, using devices whose behavior we understand in current physics.  (Look up “Alcubierre drive” and Harold “Sonny” White.)  This approach amounts to looking for more subtle behavior in what we would otherwise consider as “noise”.  Can we then tweak the signal out of that noise and harness it in a new way?  Time will tell. That time may be decades.  It may be centuries.  It may be never because nature doesn’t behave that way.  But it will be interesting to see what clues can be discovered on Earth in the next few years.

Requirements gone wild

And now for something completely different.

A colleague and I were trying to explain the basics of rocket propulsion to someone.  The subject of putting nuclear bombs behind a thick plate to produce thrust came up.  (We didn’t say “Project Orion“. But if you know what that is, that is effectively how the discussion went.)

When we discussed exploding the bomb very close to the plate, we were asked what sort of material would be used that wouldn’t be slowly destroyed in the process.  The conversation then went…

“Unobtainium.”
“What’s that?”
“It’s what you can’t obtain!”

At this point, we were berated for being scientists and engineers with no creativity.  Now, of course, we laughed it off.  I later pointed that there is a nice video that describes the predicament that engineers get thrown into with impossible requirements.  Engineers here will understand.

Sometimes, the demands of rocket science feel a little bit like this. :-)

As for lacking creativity, I thought about going to multi-dimensional space and red-shifting the color.  The part that really gave me grief was the kitten.

SpaceX CRS-3 – NET April 14

Falcon 9 v1.1 in factoryThe next SpaceX commercial resupply mission (CRS-3) to the International Space Station (ISS) is now scheduled for no earlier than (NET) April 14. This mission and other launches had been delayed due to a fire at a radar site of the Air Force Eastern Range, which supports both government and commercial launches. Also affected was a ULA Atlas V launch of launch of an National Reconnaissance Office (NRO) satellite, but this is now slated for April 10.

For CRS-3, the launch vehicle is a Falcon 9 v1.1 with nine Merlin engines, generating a total of 1.3 million pounds of thrust at launch and increasing to 1.5 million has it reaches the vacuum of space.

It will launch a SpaceX Dragon capsule with 4,600 pounds of supplies and payloads to the ISS. The Dragon will later bring back 3,600 pounds of cargo to Earth. Experiments going to the station include a vegetable production system (can it produce food that is safe to eat?) and a T-cell activation study related to the human immune system in microgravity. Several CubeSats are also being delivered to the ISS for deployment into orbit.

While it is not in any of the NASA press materials, one part of the launch being watched very closely is the first stage. This Falcon 9 first stage has landing legs. After it has sent the second stage and Dragon on their way, the first stage will prepare for re-entry to the Earth’s atmosphere. At some point, a number of Merlin engines will be re-lit to forcibly bring it back to Earth. The first stage has to survive the re-entry, and the engines have to be lit again as it hurls toward the ocean below.

In an ideal case, the Falcon 9 will light up the night sky and dance above the water before the engines are shut off. But it probably will not get far this time. SpaceX acknowledges that landing the first stage on land is the eventual goal, but there are a lot of hurdles to cross. It is much more likely that this will be the first of several attempts as SpaceX discovers what the engineering issues are with re-entry, re-light before and after entry, and deploying landing legs that have been through the searing hot trip. Rocket engines naturally operate in very hot conditions, but not normally with a headwind of dense ionized plasma coming at them.

An ocean inside Enceladus

Enceladus-PIA18071Since geysers of water vapor and ice were spotted on Saturn’s moon Enceladus by the Cassini spacecraft in 2005, an undersurface reservoir of water has been theorized. On April 4, results of gravity measurements were released in the journal Science, which help characterize the size of the reservoir. Below an ice shell that is 30 to 40 km (19-25 miles) thick, there is an ocean 10 km (6 miles) deep. Enceladus itself is 504 km (313 miles) in diameter.

The jets of water from the south pole of Enceladus contain salty water and organic molecules. Thus, Enceladus is potentially favorable to microbial lift. Linda Spilker, Cassini’s project scientist at JPL, noted that the jets’ discovery “expanded our view of the ‘habitable zone’ within our solar system and in planetary systems of other stars. This new validation that an ocean of water underlies the jets furthers understanding about this intriguing environment.”

The water ice covering Enceladus makes it one of the brightest objects in the solar system.  But because it reflects almost 100 percent of the sunlight striking it, it is also one of the coldest (-201° C  or -330° F).  At least, on the surface. [ More info from JPL ]