Thank you very much!

@@lunarmodule5 Fantastic work as always, Simon.

What if all three engines failed?

@joym6666 I’m 99% sure that 3/3 SSMEs down, no matter where the vehicle was in the ascent phase, would inevitably mean a “contingency abort”. And the term “contingency abort” is a nice way of saying “wait for SRB burnout (if that hasn’t occurred yet); and then literally bail out of the shuttle orbiter cabin through the escape hatch and hope you survive”. It’s kind of a half-step above “total loss of vehicle and crew”. Because some of the crew might potentially survive. Maybe.

@joym6666 FYI, your username makes KZfaq delete any reply comments people make that are directed at you. (Because it thinks the reply comment contains an email address, and it likes to filter that kind of stuff out. And yes, it does know how to decode the spelled-out symbols; it still knows that it’s actually an email address.) So I’d recommend changing your KZfaq username to something else; otherwise, people will have a hard time replying to you!

As always - u r more than welcome!

Yep, they were in a 45 second ATO window, so the call was hanging from the FD's lips.

I bet the FDO instantly saw on his/her graph that they weren't going to make it to orbit right when BOOSTER announced the engine cutoff.

@@demzerocool7475 each type of a abort has a period of time during the ascent, there is no decision making... if a particular failure occurs (single engine, vs. multiple for example) the decision is instant because it is preplanned based on where the failure occurred. in this case you hear the Press to ATO call about 10 seconds before the failure... that means they have entered the span where a single engine failure requires an abort to orbit, so of course when shortly after an engine actually failed there was no question about what to say or do.

Said on every mission.

Yeah… I’d just tell ‘em to punch it!

@@RideAcrossTheRiver 👍🏾appreciate it captain obvious. Except the word "Challenger" hasn't been said on any missions since 1986 nor has a LOVC Event immediately followed those words since.

@@StreamwoodExplorer Yes, because _Challenger_ was lost to that accident. "Go for throttle up" was the standard call.

@@RideAcrossTheRiver The call is actually "go AT throttle up" the throttle up has already occurred when this call is made. It means that everything is still go at the time of throttle up. It's a common misconception that its a command telling the crew to throttle up, when in fact, it has already occurred.

C-130?

Very welcome!

Thanks for the comment Spartan - appreciate those kind words

Except Jenny Howard in the BOOSTER seat at Houston.

@@RideAcrossTheRiver She was almost certainly the most stressed that day, as she had to directly monitor the engines and give the call to inhibit the sensors while hoping (though later learned to be correct) it was just bad sensor readings.

@@RideAcrossTheRiver she was the most savvy of all, her decision to request limits to inhibit greatly reduced the risk of a dangerous TAL abort and made this failure an inconvenience rather than a potential disaster.

@@canyonblue737-8 Yes, I was just pointing out she was animated.

This couldn't have been completed without your contribution Steve - as always, thanks

Totally agree

Jennifer Howard-Booster Systems Engineer

@@stargazer7644 Temps were approaching redline, if redline was exceeded a 2nd SSME would have shut down putting the flight on a dangerous single engine TAL abort case.

@@stargazer7644 The reported temps weren't true, but good question. It already occurred on Engine#1, she certainly reduced the potential for a LOC/V issue. She was owed drinks post flight that's for sure.

@@stargazer7644 But as it turned out, these sensors were indeed faulty. The center engine never should have shut down and the "right" or number two engine never should have faced the issues it faced. Yes, characterizing Ms. Howard's actions as 'Mission Saving' is going way overboard...this was akin to a mild simulation that the flight team faced many times prior to the actual launch...one engine down and another with 'sensitivities' to use NASA jargon. The absolutely proper action was to order "Main Engines to Inhibit" for this condition (following an ATO) and monitor your troubled engine all the way to MECO, which she did. This wasn't heroic, it was purely following procedure and training.

@@stargazer7644 Read my comment again...nowhere do I say that what Ms. Howard did wasn't correct, I was putting it into context. Get your facts straight before commenting...

Hope you enjoyed it!

welcome!

Thank you so much 😀

You are more than welcome

I wouldn't call this a near disastrous flight on any level. Engine out is well prepared for, and has happened on Apollo 6 and 13. The uncrewed #6 lost two engines during flight. However, your comment is an interesting observation. Machines are a kind of living being in of themselves. They try to tell you something is wrong before it breaks nearly always.

Atlantis had a near disaster with foam strike two missions after Challenger.

@@ChicagoMel23 Not foam. SRB frustum.

It’s not weird at all. When you consider the slipshod engineering quality NASA has always had going back to the Mercury program, the politics behind pushing for a horrible compromise of the original Space Transport System, and the unwillingness of NASA to acknowledge problems in order to push an unrealistic number of launches per year, it’s rather impressive we didn’t have 3 losses of vehicle and crew during the Shuttle’s history.

@@chrisbullard5901 "slipshod engineering quality NASA has always had going back to the Mercury program" What? Mercury and Gemini never had problems. Apollo had trouble because of contractors cutting corners and political demands to rush the project to beat the Soviets to the Moon. "the unwillingness of NASA to acknowledge problems in order to push an unrealistic number of launches per year" You have it backwards. Corrected: _the push for an unrealistic number of launches per year on NASA along with the unwillingness of to acknowledge problems._ NASA does and did what it's told.

Thanks as always James

I appreciated the graphics too, being the visual guy that I am.

Glad you liked it!

Glad you enjoyed it

Thanks for the kudos!

Thanks 👍

Yes

AL Bean: "we didn't have time for that (cardiac arrest) up here"

Ain't no astronaut got time for dat!

Conrad would have laughed all the way to orbit.

@@hawkdsl This scenario happened on Apollo 13.

Was AD MIL and home on leave in FL. Not this one, but we had VIP passes to the same bleachers. Didn't seem that far away if something horrible happened. When that one went, it shook us to the core. Never forget. Years later, right before I retired. I took my (new) wife. She had no idea. I have a pic of a huge smile on her face when that Shuttle went and shook her silly. I so want to see the SLS.

​@@chrisrasmussen3822 I have an extra ticket. It's now going to be in November, but I'm still excited. I went up for the first scrub, but I waited on the second one. The size of SLS is totally indescribable. 39 stories. I will definitely go back up for the Nov. launch attempt.

@@sunitamosesesq Got to stand right next to in the the VAB, on every platform level. It was incredible. Really hoping it launches in Nov.

@@SilverbackGorilla69 wow...I can't even imagine. That must have been amazing.

The OMS was "dumped" after the ATO call, which was standard procedure. The dump meant the engines fired because of the hypergolic fuel and weight was lost, which helped in the burn to MECO. They burned the OMS for about 150 seconds. Fullerty calls the end of the burn and PAO indicates that the OMS were firing after the ATO call..as far as I know there was no single ops 103 option in the ascent of shuttle at this point in its history. That came later in the shuttle program

They decided, late in the program, to roll the stack to a heads up position because it gave them better Comms through the TDRSS satellite network and also meant that the ET was in a better position in relation to orbiter at separation. When the stack was in the heads down configuration, as it was for this flight, the orbiter had to initiate an evasive maneuver which translated it above and beyond the ET to avoid collision. The heads up position meant that when the orbiter separated it was in a better attitude to allow photos/video of the ET to be taken sooner after separation, something that became very important after STS-107. There was also, because the OMS "uphill" burn was initiated during powered flight at about the same time as the heads up attitude was happening, no need for the orbiter to be in a specific attitude for the 1st or 2nd OMS burn, which on flights, before the heads up maneuver was brought in, meant the orbiter still afforded the crew a heads down horizon check as the orbiter was placed in the programme attitude for that burn. Hope that helps

@@lunarmodule5 Thanks for the answer! I wrote an email to NASA couples of years ago asking about this after I first saw stack rolling over on ET camera because I remembered several illustrations while growing up showing separation like this video. (I watched STS-1 launch on tv) They did reply back, but didn't answer the question. Again thanks.

He did

Lightens things up a bit. Funny how it later became normal to bypass OMS-1.

@@nolancain8792 But there was never another engine failure, was there?

@@Tim22222 never. Just a few close calls and scares like STS-93.

OMS firing during ascent was also a nominal procedure on missions with particularly heavy payload mass, almost like an afterburner

@@nolancain8792 "Yikes!"

Fired to provide additional thrust to counteract the loss of thrust from the SSME shut down, and also to reduce weight. The OMS engines were also used to circularise the orbit as part of launch, not just for slowing down before re-entry.

@@maxfan1591Burning the fuel also lightened the shuttle significantly

They are almost certainly thermocouples. Two pieces of dissimilar metal are fused together. At that interface, a small potential is generated depending on temperature. Platinum based ones are extremely sensitive and accurate. How and why they failed, who knows. There are many different failure modes.

@@AureliusR who figured this stuff out lol

Thomas Seebeck did, in 1821. Most discoveries are accidental, when someone was fiddling with stuff and found an unusual property, then set out to prove that some new thing was happening and did so. Other times, someone hypothesises that physics should mean that an X thing of Y type should do Z function, and they design an experiment to prove it or not, but this is rarer. We refer to the above process as science.

The booster officer literally says that they have single engine capability

So...everything is ok until an errant sensor shuts the center engine down. At the time that happens the shuttle is in position to perform two possible abort scenarios. The first of these is called TAL and basically means that the shuttle would land across the Atlantic at an air base in Spain. The other abort mode they are in is called ATO or "abort to orbit". In this mode they keep firing the two main engines they still have... and the OMS engines on the side of the shuttle. This is preferred to TAL because the crew, once in orbit, would have more options than the TAL one chance only landing option. Once in orbit it could be decided to deorbit and land back at the Cape, Edwards AFB or White Sands in New Mexico. Or they could, as they did on 51f, raise the orbit slightly and try to carry out the mission. If another main engine had failed they would not have had sufficient energy to make it to orbit and a TAL abort would have been attempted. But, it they had not attained sufficient altitude and velocity to reach Spain, and they would have ditched in the ocean. Does that help?

@@lunarmodule5 first of all,many thanks for your attention and this awesome answer. Yeah, it did help a lot my understanding about the case. As always, an amazing video/content. Greetings from Brazil. The channel is amazing, and it does a really good job about space flight.. lunarmodule5 in a nutshell.

@@lunarmodule5 Yes it helped me. Thank You

@@lunarmodule5 that greatly helps thanks. How do they dump liquid oxygen and liquid hydrogen safety during 2 engine burn launch and the OHMS burn. The pods can burn on command?

@@respectdawildo_danjones508 yes as shown, they turn the switch to ATO and then the OMS autoburn

This is the only Shuttle mission that lost a main engine. If you saw it, it HAD to be this launch.

@@brch2 its interesting because there's wasn't much made of it during the broadcast.(of course not much time to really analyze as its happening) The flamed out engine was obvious with that ultrazoom/stabilization/was slightly better footage than here...

@@crabbcake There wasn't much to be made of it. The good thing is the engine sensors caused the shutdown after they reached an ATO abort altitude, at which point there was no major problems (just adjustments and annoyances). And, the worst fear was a second engine failing, which was dealt with by the command "main engines limit to inhibit", which prevented other bad sensors from potentially shutting down other engines prematurely. This was the best possible failure launch failure a shuttle could have.

They typically go back to full throttle and throttle down slowly to avoid higher G acceleration, around three. Basically losing that engine made them lose their lifting capability (TWR less than 1.00) and had to dump fuel to reduce their weight.

The engines were re-rated prior to the first flight. 104% was the typical rate at which they operated. They used the OMS engines to help compensate for the lack of one of the main engines.

@@nolancain8792 how do they dump liquid oxygen and liquid hydrogen safety during launch??

@@respectdawildo_danjones508 They burn it through the OMS engines (the two small ones over the main engines). This stabilizes the flight as well as makes up some of the lost power from the dead engine.

The engines go 104% at throttle up though. They are rated for 107%. I wonder why they didn’t go 107%?

If that happened there was probably a high chance of catastrophic ending. NASA portrayed it as a possible abort continency but in reality, if a SSME failed before SRB burn out, the result would have been loss of vehicle and crew. They could not fly off the External Tank safely until after SRB separation.

Actually, if one or even all the engines quit before 2:30, they still would land in Spain, per TAL profile. They can't RTB because prior to 2:30, if one of the engines fail, they will be too under powered, too heavy (because of the weight of all the unburned fuel) and too low (with too little dump time), to turn around and still be able to get back to base. The chart is a bit misleading.

As lunarmodule5 points out, there was a high likelihood of the Shuttle breaking up if they lost an engine or more during SRB burn (because a LOT of stress would be put on the points the Shuttle was attached to the External Tank). But, assuming they lost an engine and survived intact until SRB separation, then they would just carry on to that point, and once the SRBs separated (and assuming the Shuttle pilot or commander triggered an abort scenario), the Shuttle would then switch its computers to the proper abort mode, and proceed to carry out the RTLS abort parameters.

@@barkingmad7407 that’s not true at all. TAL to an overseas landing site only becomes possible much later in the ascent. If one or more engine fails very early in the launch before SRBs sep there would be no options other than an RTLS, buts it’s true that a very early failure also makes RTLS impossible also… so the plan would be to begin the RTLS (knowing you won’t make the runway) and then once in a glide ditching the shuttle and bailing out the hatch with parachutes and letting the shuttle crash into the ocean. That’s the theory but many astronauts in the program were not confident the maneuver was survivable structurally before they would have a chance to get our.

@@canyonblue737-8 As you point out, an early failure makes RTB impossible, that is what I was referring to as the misleading part of the chart. The very notion that "returning to Base" was ever a viable option was never accepted by the Shuttle Flight Commanders - as you alluded to - who considered RTB a creation of NASA upper management, purely for public relations. I learned of this charade from a former Shuttle Commander whom I had the fortune of working with during the flight test and certification program on the Gulfstream G650. The Commander said that RTB was put forward to assuage public fears over the near certainty that an early engine failure would be fatal for all aboard, and the constant Congressional financial concerns incumbent with the loss of an entire shuttle due to "simple" technical failure.

Yeah but this is the only in flight abort... they were on the pad aborts

Thanks

This was the mission where they tested Pepsi vs. Coke

Well, gotta tell ya the truth. I've been married to that hot hunny for nearly 30 years now.

From a post on this page I gave this explanation...So...everything is ok until an errant sensor shuts the center engine down. At the time that happens the shuttle is in position to perform two possible abort scenarios. The first of these is called TAL and basically means that the shuttle would land across the Atlantic at an air base in Spain. The other abort mode they are in is called ATO or "abort to orbit". In this mode they keep firing the two main engines they still have... and the OMS engines on the side of the shuttle. This is preferred to TAL because the crew, once in orbit, would have more options than the TAL one chance only landing option. Once in orbit it could be decided to deorbit and land back at the Cape, Edwards AFB or White Sands in New Mexico. Or they could, as they did on 51f, raise the orbit slightly and try to carry out the mission. If another main engine had failed they would not have had sufficient energy to make it to orbit and a TAL abort would have been attempted. But, it they had not attained sufficient altitude and velocity to reach Spain, and they would have ditched in the ocean. Does that help?

@@lunarmodule5 thank you that was a perfectly clear explanation.

No, they were in an orbit that meant they could accomplish most of the planned mission

@@lunarmodule5 so the difference here is that they have flexibility with choices... interesting, I didn't know that was a thing

@@kevinwise1997 Yep. In pretty much every case, they have a particular orbit they specifically want to reach for the mission (especially in the case of launches to e.g. Mir or ISS or Hubble, where they need to very precisely match up their orbit to the orbit of the destination object). ATO is sort of a compromise where the loss of an engine (or whatever) does mean that the vehicle is operating at reduced efficiency and therefore isn’t going to be able to make it to the exact orbit they initially set out for; but they do still have enough delta-V to make it into some kind of stable low earth orbit. For planned rendezvous type missions (Mir/ISS/HST/etc), ATO would tend to mean that meeting up as intended wouldn’t be possible, and so the main mission objective would be thrown out the window. For non-rendezvous missions, the impact it’d have depends on if they just had a bunch of experiments they needed to do “in space” (basically the case here), or if they were going to release a satellite or other payload that was intended to end up in some target orbit, or whatever else they may have been intending to do that might be orbit-dependent. In any case, reaching *a* stable orbit of some sort-even if it’s not *the* orbit they wanted-is still good: both in terms of potentially being able to still get some subset of the mission objectives done (this is more applicable to non-rendezvous missions like STS-51-F) and also in terms of giving mission control more time and options for where and when to land the orbiter. If they do a TAL, they’re stuck with whichever trans-Atlantic landing site(s) are on alert for the mission; and they have to land NOW; and that’s the only chance they get. With ATO, they have somewhere in the neighborhood of days to maybe-a-week-or-two-ish to evaluate what the problem was, and then decide very carefully and deliberately about which landing site they want to use, when to come down for the best weather, and determine other factors like that at (relative) leisure.

Recent studies have found that the chance of a mission failure during the first few missions were 1 in 9.

The Shuttle Orbiter was a perfectly sound design. The booster system was a Nixon-era relic where President and Congress demanded a reuseable system then paid only for the Orbiter, telling NASA "make do."

@@sidv4615 Apollo was less safe.

@@RideAcrossTheRiver you’re correct, but only partially, the shuttle as an overall vehicle was safer than the Saturn V but the crew survivability was higher on the SV cause apollo had a launch escape system unlike the shuttle. Also the space shuttle was very unsafe, not just because of the solid rockets, Look at Columbia, the fact that an entire space shuttle was brought down by a piece of foam no larger than a briefcase just proves the razor thin margins the shuttle program was operating on.

@@sidv4615 Again, the booster system was the culprit, and the blame and blood lie with Richard Nixon and his cronies in Congress. They directed NASA to design a reuseable booster and Orbiter; then funded only the Orbiter. The loss of _Columbia_ was the obverse of the loss of _Challenger._ In neither case was the Orbiter to blame. The foam that hit the Shuttle was travelling at 600 miles per hour. Why did you leave out that detail? What craft can withstand a strike like that? Perhaps you forget how the Apollo CSM had total and partial failures across MANY missions. The STS Orbiter never failed in any way because of any design flaw within it. The failure was the make-do booster system. STS was operated safely; especially after STS-51-L. Elon Musk's profit-based system is a deathtrap.

I don't remember this launch as well. Any idea as to how many orbits before it came back and landed?

It wasn't kept quiet (I mean, there is plenty of documented footage of it, including this vid), it's just that when looking at the history of the program, the same Shuttle being lost just 6ish months later kinda overrides what was basically a non-event in comparison.

@@brch2 - But that's the thing, the NASA engineers knew it was _not_ a non-event at all. It was an incredibly close call that very nearly resulted in the loss of the orbiter and crew. And they basically did absolutely nothing about it except hope it didn't happen again. Which was why they downplayed its seriousness..

@@HailAnts I didn't say it WAS a non-event. I said NASA didn't hide anything about this mission (and there's very little they hide about most missions if people care enough to pay attention). I said in comparison to the soon after loss of Challenger this became a non-event (in the eyes of the public). NASA tells the public quite a lot. The public in general just really doesn't care. And I'm quite sure NASA did something about the issue that caused the engine to go out. They found out the sensors were bad, and replaced them. And the fact there was never another abort due to engine outage is a good indication there was no "hidden" problems they covered up.

...they didn't use the main engines for deorbit

The name CHALLENGER did its job of challenging every mission, shuttle and NASA. But each challenge came with new innovation to the shuttle program. The rendez-vous pitch maneuver or backflip prior to docking was a new innovation to expose the heat shield to crew on ISS for photograph to inspect them for damage

@sam linton nein

No

Nope, wrong on both points. On this flight, because of the Abort to Orbit the OMS engines were fired/dumped to provide a weight loss and a boost uphill. It was the only time it happened until OMS were used to direct orbit a shuttle negating the need for the normal OMS1 burn, but that didn't happen till late in the program. On this mission and all flights until the late 90s the shuttle did not perform the heads up roll profile, hence the tank was in the configuration seen in the animation. without that roll the shuttle ended up under the tank with the shuttle earthside and the tank spaceside. Lastly, I know I got it right as I consulted with NASA mission controllers who helped launch shuttle and who know their stuff. Hope that helps

I remember narration some nominal flights that the OMS engines fire upon SRB separation. The narrator stating "...Orbital Maneuvering System engines now firing, giving the orbiter a 'kick in the pants' ..."