Apollo 15 airborne tracking camera [SILENT]

[Leddyzee]

What aircraft was used as the camera platform?

[JuggaloOzi]

It's not exhaust flames during the stage separation. Retro rockets have to fire to pull the S-1C out of the way. These are hidden in the engine fairing and fire before the 2nd stage ignites.

[usaeagle1776]

from this to hitchin rides with the russkies....wow.

[jetfreak4]

The fact that the Saturn V came out of 1960s technology still takes my breath away. Even by today's standards it has no equals. It's launch escape tower had more thrust than the first Mercury rockets less than ten years before its time. How we got from the Boeing 707 to the Boeing 747, and from the Mercury to the Saturn V in just over a decade is unbelievable. Even crazier still is that we went from barely being able to stay in orbit to landing on the moon in under a decade. Just fucking unreal.

[charliegoodboy]

Nice footage, among the hours and hours available to the public for over 40 years, but finally widely viewed thanx to Youtube...Bravo!

[jetfreak4]

@charliegoodboy It's still unbelievable to me this was 40 years ago....manned spaceflight I can say is really the only area humans haven't improved really improved on since 1972 technologically. It's a tragedy and in my opinion a disgrace that the Saturn V was thrown away after such a short period of me. It could launch an entire space station in one mission, carry the heaviest payload ever carried into LEO for the moon missions. I would trust my life with that rocket over the shuttle.

[charliegoodboy]

@charliegoodboy It did lift skylab into orbit. They have a complete skylab at the Smithsonian in washington dc, you should check it out. ISS is massive though, and pretty awesome especially with that viewing module they added a couple years ago.

[disorganizedorg]

I had read that on this launch in particular that S-II ignition occurred while the S-IC was closer than it normally is, resulting in a potentially dangerous condition. This video appears (to my untrained eye) to confirm that.

With astronautix down due to a DOS attack (by children, I assume; I can't imagine a less offensive target), I'm unable easily find further info...

[Tyrannobeast]

@disorganizedorg Apollo 15's Saturn V was the first without the ullage motors on the S-IC/S-II interstage (so they could save weight for the rover and stuff). I'm guessing the amount of time it would take for the S-IC to fall away on its own was miscalculated. The concern was that the J-2s might ingest their own exhaust, which would be, uh, really bad!

[disorganizedorg]

@Tyrannobeast Thanks! That certainly makes a great deal of sense.

[Tyrannobeast]

@disorganizedorg Always good to help someone out.

[jetfreak4]

What's more is that in today's dollars, it would cost $1.1 billion, including construction costs, to launch...the shuttle costs $1.5 billion per launch. Expendable rockets are actually cheaper to build than reusable ones...most likely I'd figure because of the absence of maintenance and repair costs. The launches, while not nearly as frequent, could accomplish the equivalent of four shuttle launches. The last Saturn V flew a fully assembled and operational manned space station into orbit.

[jetfreak4]

That flame trail is just amazing. Has to be at least 5 miles long. And to somebody that made a comment about this being duplicated, I seriously doubt it. The Saturn V had it all...it could fly extremely heavy cargo and people into space simultaneously and out of earth's orbit. NASA's Mars Rockets, had they been designed, would've had one carrying people, one carrying the cargo. There has never been a successful rocket as large, powerful, or as heavy as the Saturn V since the Saturn V .

[TheLordstrider]

Why is the rocket burning tail changed from fire to just looks like smoke ?

[battersby255]

Awesome even 40 years later.

[dks13827]

will this EVER be duplicated ? the odds are, IMO, not !! sad. :(

[lardo444]

yes i realize that, but someone did the math, and changed the wieght to gallons, then the distance to "no burn" and came up with 5 inches per gallon. so if it burned all its fuel in 12 min. what distance is that? divided by the amount of fuel.

peace, lardo.

[ugowar]

@lardo444 I don't know the downrange number off hand, it could be dug up online. Still, that's a useless metric. Why stop counting after 12 min as the rocket kept going at the same speed afterward. It also didn't use up all the fuel afterward. It only used up all the fuel after translunar injection which was some hour and a half after launch. If you take that time and distance it travelled until then, you'll get a much better "mileage".

[lardo444]

@ugowar ok, i'll try to find it. all they were doing was trying to explain the amount of fuel it took to get the monster Saturn 5 into space. they were HUGE. and it took alot of fuel to get it there. thanks for the response. i've got some work to do.

peace, lardo.

[thetrolone]

i was waiting for the damn gun to fire for over two minutes!

[ugowar]

@thetrolone LOL!

[lardo444]

@ugowar i read somewhere that the Saturn 5 rockets got 5 inches per gallon of fuel.

do you know what the fuel ratio per mile was?

peace, lardo.

[ugowar]

@lardo444 There is no fuel ratio per mile for a rocket. It's not traveling on a road. While the rocket burns its fuel, it's continuously losing mass so the same engine thrust causes it to accelerate faster and faster. Not only does it pick up speed, but it's *rate* of picking up speed increases. Even though it looks like it's moving slowly immediately after liftoff (which is also an illusion as the rocket is huge), 12 minutes later it's going 17 thousand mph.

[jetfreak4]

@ugowar 17,500 mph actually, to add more stunning news. I actually noticed that the Apollo 15, 16, and I'm assuming 17 missions did not get into orbit at as high altitudes as the previous Apollo missions. 15 and 16 got into orbit at about 95 nautical miles high, while the rest of the missions reached orbit at over 100 nautical miles high. I think the weight of the rocket increased with each mission due to more equipment, especially the lunar rover, but i don't know if that explains lower orbit

[roamingcroat]

@jetfreak4 You're spot on. The J missions (15 through 17) landed more mass on the Moon, so they needed to do a whole lot of modifications to make that possible. The LM had its descent nozzle extended, the CSM put the LM into its descent orbit (unlike 11 and 12, where the LM put itself in its staging orbit), and the parking orbit around Earth was lowered. All of that added to the mass that could be landed by the LM.

[jetfreak4]

@roamingcroat I think they also increased the total thrust of the first stage to 7.83 million pounds, at least that's what it was on Apollo 15. I actually also found out that the thrust of the first stage increased dramatically on the Saturn V after the rocket passed through maximum dynamic pressure. After max Q, the first stage was hammering out an astonishing 9 million pounds of thrust due to the much lower air resistance and smaller density of the atmosphere.

[jetfreak4]

@ugowar Try 17,500 mph.

[jetfreak4]

@ugowar You're about the decreasing mass, but after maximum dynamic pressure the engine thrust actually increased to around or in excess of 9 million pounds total before center engine cutoff. So the engine thrust itself was actually increasing due to the thinning atmosphere and basically absent air resistance. From max Q to staging (just over 1 minute), velocity increased by 5000 mph, its altitude by about 30 miles, and its downrange distance by over 50 miles. One of the greatest machines ever.

[NelielTuOderswank]

@lardo444 You can do the math to calculate the rockets efficiency with both the Delta-v and Bernoulli equation.

[springhill1958]

Odd how the flames climbed up the side on this one but not on Apollo 8, I would think they would behave identically, but go figure. Each engine has a 55,000 hp turbine on it, that is cranking it out!

[ugowar]

@springhill1958 The flames climbed up on all the Saturn Vs, just the camera angles were not good for picking it up. This camera was located much more downrange than any ground cameras so it got a good sideways look at the rocket at the time the flame started creeping up. On a related note, if you're familiar with SpaceX Falcon 9 inaugural launch a couple of months ago, onboard footage also showed the exhaust from 9 engines engulfing the engine fairings and charring them eventually.

[theCookieMonster9999]

@springhill1958 There are no turbines on the Saturn V. They are LOX engines.

[springhill1958]

@theCookieMonster9999

cookymonster, there is a turbine on each engine, that is what powers the pumps to feed the engines, so there are 11 turbines on a saturn V, 5 first stage, 5 second stage, and one third stage

[uzimodem]

awesome.

[kush2121]

at the time of S1C staging it was traveling at a speed of around 6100 mph, at an alt of 42 miles. The fist stage continued to an alt of about 68 miles on inertia alone. At the end of the video I'd say it's probably somewhere around 62 miles in alt. Not an exact, but just an estimate.

[kush2121]

This video is fucking amazing. Thank you for sharing it.

[ftucyk]

I have a message to all the stupid people, hwo don't believe in the Apollo program! Look at this video!

[Beamshipcaptain]

6.6 miles per second, and the corret trajectory, heading East to take advantage of the Earth's 1000 mph rotation on its axis to give the ship a 1000 mph boost.

[donkeyxotedelamanche]

Geee ... see how the exhaust flames creep upward PAST the Interstage then back to almost the fins ... you can see the 1st stage turned black from the kerosenne ... it is the farthest that I have seen it creep up a Saturn!

[Beamshipcaptain]

These engines only had to work for 150 seconds. They burned kerosene and liquid Oxygen.

[DSCH4]

Where was this camera located? My guess based on the orientation of the vehicle is that it is on a ship in the Atlantic, some distance downrange and to the south of the flightpath.

[ugowar]

Do you actually read video captions and descriptions? It says clearly it's an airborne camera, hence it's on an airplane.

[DSCH4]

Sorry, I neglected the description this time.

[galacticinquisitor]

Not just in the description but the video title as well.

[aeroflying]

Be patient with one another.

[SecretSepp]

are they going to space?:)

[666HellKnight]

They are going somewhere alright!

[joshig1983]

What altitude is the rocket at in the end of the video? Is it almost in orbit?

[ugowar]

I don't know what the altitude was, my guess would be something like 100 kilometers. It doesn't take altitude to reach orbit, it takes velocity and I think at the end of the video it was still less than 1/2 of orbital velocity. The rocket was gaining more downrange distance than altitude at that point since it was pretty much out of the atmosphere so it didn't need to climb as fast anymore.

It took 11.5 - 12 minutes for Saturn V to reach orbit and this video starts about a minute after launch.

[ftucyk]

I know it takes velocity to reach orbit., it's like free falling. The gravity on 400 km is almost the same as on the Earth.

[dopje31857]

Very impressive footage!

[billt460]

Is "POGO" when the engine bells move back and forth on their gimbals? Also, how were they going to simulate harsh reentry conditions, by burning the engine during downward decent to simulate a Lunar Trajectory reentry of 25,000 MPH?

[ugowar]

Pogo is a longitudinal oscillation of the whole rocket and is brought up by natural oscillations of the engines and the thrust frame, coupled to the prop feedlines. The term comes from a "pogo-stick" and is like sitting on a jackhammer. The phenomenon doesn't necessarily occur on all vehicles, but if their frequency ranges are susceptible they can do so - Apollo 4 for example didn't experience pogo. Apollo 13 experienced pogo on 2nd stage, which is the cause of early inboard shutdown.

[ugowar]

On Apollo 6 I believe they planned to reignite the S-IVB to put the spacecraft in a translunar-like trajectory and then after a while climbing out of Earth's gravity well, they'd use the Service Module to change direction halfway up and bring it back down to Earth. After that maneuver, the S/C would still be high above Earth but not moving very fast (hence the SM burn was adequate), but with a lot of potential energy. It would then hit the atmosphere at 11.27 km/s upon reentry.

[blablubb12345]

AFAIK, they did a successful high speed reentry during Apollo 4. As you said, the same test on Apollo 6 failed as the CM was not fast enough to simulate a reentry from a lunar flight path.

[ugowar]

Pogo is essentially a resonance and once resonance starts feeding off itself, it can be very destructive.

The pogo on Apollo 13 was severe, the inboard engine almost ripped itself out of the thrust frame and caused the engine thrust chamber pressure to oscillate wildly. This is what caused the computer to shut that engine down - it thought it was failing and in the process probably saved the Apollo 13 crew.

Apollo 8 also experienced a milder case of S-II pogo.

[billt460]

I can't imagine how powerful the fuel pumps had to be to feed those engines 15 tons of fuel per second. An incredible machine with a perfect flight record. Not one failure except for the center engine on Apollo 13.

[ugowar]

Apollo 6 was a failure although it managed to get into orbit. It experienced severe POGO at the end of 1st stage burn, enough to cause an abort had a crew been onboard. Later on, 2 engines cut out on 2nd stage causing Apollo 6 to enter an elliptical parking orbit. Then the 3rd stage wouldn't restart, again a problem with the J-II engine.

The mission was salvaged by using the SPS engine burn instead, but it couldn't simulate the harshest reentry conditions an Apollo heat shield could encounter.

[billt460]

Thanks, one more question. When you look at the F-1 engines as it lifts off, the flame cone is very sooty where it exits the nozzle. Then several feet below the nozzle the flame cone is almost too brilliant to look at. It looks like the bulk of combustion is taking place out of the nozzle, and the engine is running too rich??

[ugowar]

That's a common question and has to do with the way the engine operates. F-1 has a gas generator that burns fuel rich and provides gas for the turbopump turbine and this gas is typically vented separately to the engine nozzle - see for example SpaceX Merlin 1 engine. With F-1, however, the exhaust is ducted into the nozzle below the main bell and above the nozzle extension. Gas generator exhaust is much cooler than the combustion chamber exhaust so it provides cooling to the nozzle extension.

[ugowar]

So what happens is this: the outer layer of the F-1 exhaust is the cool gas generator exhaust, with the bulk of the hot exaust flowing underneath it. A few feet from the engine exit the (fuel rich) gas generator exhaust is heated enough that it starts burning the excess fuel in the oxygen from the atmosphere.

It's this exhaust burning what gives such a brilliant flame to a rocket engine. Once it reaches altitude, oxygen concentrations get too low to support combustion so the plumes dim out.

[billt460]

Why does the flame cone spread out so far sideways as the launch vehicle gains speed and altitude?

[ugowar]

It spreads out because the exhaust coming out of the nozzles is still very hot and at high altitudes there's no significant atmospheric pressure to prevent that expansion. As a result, the hot exhaust expands.

You can think of it this way - at the engine nozzles the exhaust has a certain pressure, which is constant. If that pressure is the same as the atmospheric pressure (that's optimal), the exhaust just moves away in a straight line - just like when the rocket lifts off.

[ugowar]

When the outside atmospheric pressure drops, the exhaust expands. The majority of it is still moving opposite the rocket motion, though and the engines are actually more efficient at altitude, even though some exhaust goes "sideways".

Usually the engine nozzles for rocket 1st stages are sized for sea level atmosphere which is why the exhaust doesn't spread out at the ground, only at altitude.

I hope that clears it up a bit.

[britishareawesome69]

That was the first mission to use the luner rover

[stuartthegrant]

Thats more like i hoped..Thanks

[stuartthegrant]

I find it very hard to accept that the plans have been lost. The Saturn V was the iconic booster of its and any era.

Post shuttle launchers seem to be going back to this technology, 1.5 million pounds per engine thrust...not to be sneezed at.

[JohnCerveza]

is it true, do you know, that the blue prints for the Saturn series were destroyed and there is no record of them

fantastico video meng!!

[ugowar]

No, it is absolutely not true blueprints were destroyed. They're still being kept on microfilm to this day. If NASA's new Constellation program wanted to for example restart production of the F-1(A) engines (as was suggested in some proposals), they could have done so.

[JohnCerveza]

according to Bill Bryson, the plans were lost but I will take your word for it. This was the greatest technological acheivment of the 20th century, bar none and I wholeheartedly support the space program as our econoimic destiny.

[ugowar]

The most useful parts of the Saturn V today would be the engines, the rest of the vehicle is basically just tankage and if we were to rebuild it we would be able to do it better today. There's no particular reason to go back to this exact same Saturn V since we'd do certain things differently today and probably use different materials.

The engines, however, represent the significant advancement done in the R&D back then and would still be viable today, with further improvements.

[ugowar]

For example, the J-2 engine of the Saturns is basis for the J-2X engine the Ares I and V rockets are slated to use. They have uprated performance specs from the original engines.

Similarly, the F-1A engine would have something like 30% more thrust than the F-1 in the Saturn V, making it truly the most powerful liquid fueled engine ever. IMHO, NASA should have opted to restart their production instead of sticking for Shuttle derived technology which might end up costing them more in the end.

[ugowar]

The Ares V is running into performance issues as the Orion spacecraft keeps getting heavier and the rocket can't keep up. The problem with cryogenic first stage engines (from the Delta IV rocket) is they can't produce very large thrust. Their specific impulse is superior to kerosene fueled engines, but in the first couple of minutes of the flight it's all about thrust. That's why the Ares V solid rocket boosters keep getting bigger and soon won't look anything like the Shuttle SRBs.

[OhMyScience1]

Very cool video! Thanks!