SpaceX Falcon 9 – Possible Explosion | Hacker News Reader

SpaceX Falcon 9 – Possible Explosion

zarya.info

106 pointsdingaling31 comments

This has been discussed further here:

http://www.reddit.com/r/spacex/comments/1nfl59/spacetrack_is...

Quote from SpaceX via twitter.com/spacecom:

"We have no reason to believe there was an explosion of any kind [of second stage]. Based on previous launch experiences we do know it's common for the first measurements from Space-Track to not always be accurate. It usually takes a few days for them to sort it all out and that's with fewer objects to track."

Also it was said that there was an anomaly on second stage relight resulting in a lot of unburnt fuel to be expelled creating a gas cloud.

This can be seen here. http://wikkit.tumblr.com/post/62684205892/tracking-a-new-spa...

Seems like thats all this is.

Makes sense. I can't really think of what could've exploded on the second-stage without also causing the entire vehicle to be obliterated. Whereas a bunch of globs of kerosene fuel would promptly freeze and be highly reflective.

The gas cloud could apparently be seen from the ground. Someone snapped a pic from Reunion island, near Madagascar: http://wikkit.tumblr.com/post/62684205892/tracking-a-new-spa...

EDIT: Here's more pics from South Africa http://uforsa.co.za/2013/09/mass-ufo-sighting-on-29-septembe...

Thanks for the reddit link, I hadn't seen this discussed anywhere other than on the SeeSat mailing list. Even on that list there isn't consensus on what this debris field means, if anything.

The zarya.info article is rather breathless and conspiratorial but was the best I could find at the time.

I'm in no position to dispute the author's technical competency, but on the basis of a series of haranguing messages I received from him after making a small space-related thingy (http://wheresthatsat.com), I believe he does regard US-based space activities (including everything from NASA to commercial enterprise to hobbyists like me) with blanket disdain. That's consistent, for better or worse, with the conspiratorial tone you note.

The speculation about the feed cutting is not very reasonable. The feed cut all the time in all phases of the flight, and that always caused also control room voices to be cut as well. Their software was just configured like that.

Entire article seemed rather aggressive.

How do I get those spacetrack graphs? Do I have to be a .mil person?

Is there a DIY space tracking service out there?

> How do I get those spacetrack graphs?

NORAD's Space Track service makes the raw two-line elements available, but over the recent decade they have tightened usage and distribution restrictions. By the letter of the terms of service, one who downloads the data may not disclose the raw data or anything derived from it.

https://www.space-track.org/documentation#/user_agree

As a result, amateur satellite tracking groups have to 'disregard' Space Track data and determine orbital elements through their own observations.

An exception exists for TLEs redistributed by CelesTrak.com. Sources: http://celestrak.com/NORAD/elements/notice.asp#Update16 and personal correspondence with the operator.

(Note also that the Space Track terms do not prohibit individuals from requesting accounts for personal use.)

Aren't the works of the federal government, by letter of the law, public domain? Wouldn't this negate their terms of service?

Silly. Article doesn't seem to understand staging, which makes any analysis of launch vehicle failure pretty questionable.

If anything exploded, it would have to be second stage after payload deployment-and that wasn't shown in broadcast.

It is vaguely possible that "fail to relight" was used to say "explode", but that is very evasive even for SpaceX. Also, explosion is not a common failure mode for liquid rockets (until they crash).

Anyway, rather unlikely. If those radar sigs are real they are probably fuel or cube sat launch bits or something.

Further information: one of the cubesat payloads separated into seven different bits (three payload spheres and four sabot pieces). Another is at least two pieces when deployed. Note that the cubesat launch system is spring-loaded, intentionally scattering the payloads.

So you'd expect at least 15-16 objects from the launch; 20 isn't all strange.

Assuming this is true, and there actually was an explosion, and it was caused by the SpaceX rocket: I wonder how does this amount of space debris impact and potentially endanger future orbit flights. As much as I support technology development and private space exploration efforts, I think that private companies shouldn't be allowed to pollute the orbit without retribution. I hope they figure out the cause, and fix it, and not simply cover it up.

Have you heard of the Kessler Syndrome? (http://en.wikipedia.org/wiki/Kessler_syndrome)

I always wondered what the odds were of such a collision occuring in space. I realized that the surface of the orbit area is way larger than the Earth's surface. So I imagined satellites and debris located on and moving around the Earth's surface, and wondered what the odds were of them colliding in such a situation. I imagined they'd be extremely low, making the odds of a space collision even much lower.

Not sure I explained it clearly, and it might be a wrong assumption, so feel free to enlighten me.

So, it's certainly happened:

http://en.wikipedia.org/wiki/2009_satellite_collision

I'm nowhere near talented enough to talk in terms of "odds" with respect to satellite collisions, but it's worth noting that certain orbit geometries are going to naturally see a lot more density because several satellites want to be in a somewhat similar orbit for various reasons.

Another one:

http://www.space.com/20146-russian-satellite-space-junk-thre...

Surprisingly large. This isn't accurate even to within an order-of-magnitude: it's just to get some insight. The surface of the earth is (to the nearest power of 10) ~10^9 km^2. LEO satellites go up ~10^3 km, so that's ~10^12 km^3 of volume for them. A satellite traverses ~10^8 km/year (that's a lot!), so if it has ~10 m^2 cross section (10^-5 km^2), its path encompasses a volume of ~10^3 km^3/year. Under some simplifying assumptions, the probability of two arbitrary satellites colliding is something like ~(10^3 km^3/year / 10^12 km^3) = 10^-9/year. There's ~10^4 satellites, and the rate of collision goes as the number of pairs of satellites ~N^2, so the rate at which any two satellites collide is (10^4)^2 * 10^-9/year = 10^-1/year or once per decade.

I think the particularly "unintuitive" parts of this are, one, the incredible distances travelled when you sustain Mach 20 for years (10^8 km/year); and two, the quadratic scaling (10^4*10^4).

NASA has some nice pages about orbital debris. They inspect everything when it comes back to Earth to check for impacts, and they have photographs of micro impacts.

(http://orbitaldebris.jsc.nasa.gov/)

Site might not be available because US politics is batshit insane.

The photo gallery has some images of debris impacts. These micro impacts seem to be really common. The amount of debris is pretty large.

> More than 21,000 orbital debris larger than 10 cm are known to exist. The estimated population of particles between 1 and 10 cm in diameter is approximately 500,000. The number of particles smaller than 1 cm exceeds 100 million.

The surface area of Earth is about 510 million square kilometers.

> As much as I support technology development and private space exploration efforts, I think that private companies shouldn't be allowed to pollute the orbit without retribution

Yes; even governments shouldn't pollute orbits. One such example:

http://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_mis...

http://i.imgur.com/QmWXjCP.jpg

That's a very big assumption at this point. There is no evidence whatsoever that an explosion occurred.

There were numerous reports of visual phenomenon consistent with the vehicle simply venting its fuel. The resulting gas cloud from such an event often results in inaccuracies in tracking.

Weirdly enough in the long run you want to blow up stuff to keep orbits clean. MUCH better surface to volume ratio means faster de-orbit. This is a classic short term vs long term thinking problem. In the short term you're better off with fewer trackable objects but in the long run you're better off with no trackable objects at all.

If you're really bored you can run calculations on deceleration vs mass per surface area. From memory there are (admittedly extremely low) orbits where a rail-car shippable steel construction I-beam, actively pointed end-on, will orbit for months but a hot air balloon would deorbit in less than one full orbit.

Aren't there better solutions? For functional satellites, of course, you could just de-orbit them (so that they burn while re-entering the Earth's atmosphere), but even for passive objects, maybe you could steer them so that they start falling towards the earth. The Wikipedia article on Kessler Syndrome[1] suggest using lasers, but I guess other ways are possible: if you intend to "blow them up", you might as well redirect the rocket to explode slightly above the orbiting object, so that it is not damaged, but only pushed towards the Earth.

[1]: http://en.wikipedia.org/wiki/Kessler_syndrome

One day we're going to need Kessler Cleaners in high geosync orbits to use lasers to "encourage" debris to deorbit.

There are some orbital mechanics problems. You can't "steer" in orbit. Shoving down at any sane rate results in going up half an orbit later. The best place to blow it up would be in front of it. A couple hundred m/s is all it takes in some cases.

There's a free windows only game called Orbiter under continuous (ish) development since early 2000s. Its informative about the weird truths of orbital dynamics. Several years ago I went thru a phase of flying between Jupiters moons for fun.

There's probably a startup idea in creating what amounts to a E6B for orbital mechanics. The problem is making it elegant and easy to use. Anybody can open matlab/octave/mathematica/whatever and say "just enter a bunch of equations". I'm not sure the MFDs in orbiter are the wave of the future either. And its easy to get sucked into the trap of making it too simple for the .edu market such that it can't actually simulate anything. Its a hard problem. Maybe more for a PHD project because I'm mystified how to monetize.

This guy reads like the Glen Beck of space :-). I was intrigued at how consistently the downlink seemed to interrupt when it switched views, I paused the video a couple of times to try to figure out what the 'other' view was that it was trying to switch too. I would not be surprised if SpaceX indicated a partial failure in their communications downlink which was triggered by selecting that view, but it is a huge stretch to go from some communications hiccups to "possible explosion."

...or not: "Upper Stage of New Falcon 9 Rocket Did Not Explode After Launch, SpaceX Says" http://www.space.com/23038-spacex-falcon-9-rocket-explosion-...

Nice try, russians.

Ad hominem much?

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