The Incredible Transformation of a Boeing 747SP into a Space Observatory - SOFIA!

NASA and its Partners have just flown their last missions with Sofia a fantastic flying telescope mounted on the back of a Boeing 747sp but what actually was the Boeing 747sb and why did NASA choose such an unusual aircraft for this role stay tuned the development and introduction of the awesome Boeing 747 was a major and future altering step for Boeing it came at a time when commercial Aviation was expanding and changing rapidly but the birth of the Boeing 747 program and the reasoning behind it is a subject that we will need to cover in more detail in a future video now we will focus our attention on the Boeing 747sp the baby 747 this somewhat less known aircraft was created for a small niche in the aviation Market back in the early 1970s the SP was based on the Boeing 747-100 and it was ideal for very long long-haul flights but with relatively few passengers today the aviation industry refers to these as long and thin roots back in the 1970s and 80s the aviation world was settling in on the Hub and spoke operating model in this model a few very large airports were designated as hubs and to these airports smaller Regional aircraft would fly in passengers who would then board long-haul flights to fly out where they need to go in the world because of this model these airports would have to catered with a huge volume of passengers and a limited amount of takeoff and Landing slots meaning that bigger aircraft who could carry a lot of passengers would be preferred the Airbus A380 is a later product of this model because of this for most Airlines a Boeing 747 that carried fewer passengers wasn't really an attractive idea but there were some very long routes that were too long even for the standard Boeing 747-100 and the even longer range 200 to do because of this Pan Am and Iran air jointly approached Boeing and requested a shorter Boeing 747 specifically for lower demand flights between JFK and Tehran obviously this was back when the US and Iran was in much better terms than they are today this is where the ultra long range Boeing 747sp came into the picture there was also another incentive to develop the SP size wise Boeing didn't have any aircraft that could satisfy the market between the 707 and the 7 4 7 at a time this would eventually change with the introduction of the Boeing 767 but up until then the 747 SP would fulfill two roles firstly it would provide an option for mid-sized wide bodies to Boeing's customers and secondly it would have the extra long range that was necessary for some Ultra long-haul lower demand routes looking back at it you could actually say that the Boeing 747sp was actually ahead of its time given that Boeing would later decide against the developer of a newer version of the SP in favor of the Boeing triple seven which has shown what a remarkable business segment this size of aircraft actually is today smaller very efficient aircraft like the 787 are getting more popular for long thin routes especially since many airlines have moved away from the Hub and spoke model in favor of the point-to-point model where airlines are flying like the name suggests point to point from much smaller airports but what most people don't realize is just how extensive Boeing's engineering modifications were when it made the 747sp if you look at the SP you can clearly see that its tail fin is taller than that of other 747s this tends to be the case for shorter aircraft where the vertical stabilizer is closer to the wing and the engines it has to be bigger because the stabilizer and the router has a smaller moment arm to stabilize the aircraft and also has to counteract the effects of asymmetric trust if the aircraft experiences an engine failure a bigger Fin and a larger Rudder will sort out both those problems but there are some other differences as well including some that directly affected NASA's decision to use it as a platform for its flying telescope and I will tell you all about them after this short message 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freely and safely today by getting an exclusive nordvpn deal at nordvpn com slash Mentor now plus you don't have anything to lose with nord's 30 days money back guarantee thank you nordvpn for sponsoring this video usually when an aircraft manufacturer wants to make a longer or shorter version of an existing airliner they just add or remove sections of fuselage to make this happen the Boeing 737 family is a great example of that obviously there's a lot more to this involving the redesign of the wing and its high lift devices and the power needed from the engines as well as the number of emergency exits needed but if we concentrate on the fuselage the special design of the 747 means that making a shorter version was a bit more complex if you look at the 747 SP from the side you'll see that the rear section of its Upper Floor hump is directly over the area of the fuselage which meets the wing this area is called the wing box and it's a crucial part of the aircraft design as it holds and attaches the wing to the rest of the structure so Boeing actually had to redesign this section of the aircraft specifically for the 747sp to allow the Upper Floor and the wind box to overlap this then gave Boeing the idea to extend the Upper Floor for its other 747 so that its rear end would also be over the wing box meaning that ironically This Plane the shortest 747 of them all actually made it possible for Boeing to enlarge the 747 by introducing the stretched Upper Deck this stretch later became standard in the passenger versions of all 747s after the 747-200 model as for the rear of the cabin the 747sp had a very significant design change there as well normally the fuselage of the 747 tapers and get thinner very gradually as it reaches towards the tail so when Boeing tried to design a shortened version of the aircraft it had to introduce a visible Step at the point where the passenger cabin ends and the tail continues after the rear pressure bulkhead the unusual shape that comes as a result of this meant that Boeing had to strengthen this part of the fuselage considerably and that came in handy when NASA and his Partners start to work on the stratospheric observatory for infrared astronomy or Sophia the subject of this video of course there were also other things that worked in favor of the 747 SP at this time when NASA was looking for an aircraft for this project for example by that time many uses of the 747 SP was switching to more efficient aircraft like the triple seven and that meant that there was very high availability of cheap 747 SPS at the time that fact together with the fact that the SP still had that nice wide fuselage of the 747 likely was the most important factors in choosing this particular aircraft type now the reason NASA had for making a flying telescope platform was to enable scientists to observe the sky with as little impact from the atmosphere as possible this is obviously important for all telescopes out there and it's the reason why ground-based telescopes tends to be placed at the tops of mountains but it was extra important for the telescope used in the Sofia project because it was an infrared telescope humidity in the atmosphere blocks much of the infrared Spectrum so a flying platform that could cruise at 41 000 feet above nearly all of the humidity in the planet atmosphere was really attractive for this purpose and the 747 SP actually had a maximum Cruise altitude of 45 100 feet but another giant benefit of fitting the telescope to an aircraft is that an aircraft moves fixed telescopes can only observe the sky either in the Northern or the southern hemisphere but a flying telescope can go wherever it's needed also it's worth noting here that Sophia didn't just materialize out of thin air a lot of people working on this project previously worked on the QPR Airborne Observatory or KO a product that used a c-141 military cargo plane as its platform even the KO wasn't the first such aircraft NASA previously had the Galileo Observatory based on a convert 990 but the telescopes on those aircrafts were much smaller the one on KO had a diameter of 36 inches or 91.5 centimeters but despised that small size the KO team discovered the rings around Uranus and it verified that Pluto had an atmosphere among many other things and these discoveries helped incentivize and fund Sofia and its much larger telescope with a diameter of 8.2 feet or two and a half meters which is giant the telescope was designed by DLR in Germany which was NASA's key partner in the project but figuring out how to fit such a big telescope on an aircraft and then actually operated wasn't easy initially the idea was to place the telescope in front of Sofia's wings but further studies showed that the installation behind the wing was going to be much simpler and more economical now in case you're wondering there's no glass or anything else in front of the telescope when it's operating in flight for a flying telescope to work its mirror must have a view of the sky that is as unobstructed as possible and to make this happen the 747sp had to get a new rear pressure bulkhead fitted between the wing and the telescope this would allow the telescope to be out in the open at altitude while keeping the rest of the aircraft pressurized for the crew on the scientists working there NASA and Raytheon further modified the aircraft fitting a door that was 4.1 meters or 13.5 feet wide and 5.5 meters or 18 feet tall arcing along the fuselage now that is a huge door bigger than the doors on some cargo aircraft but what's different here is that those cargo aircraft they can't fly unless their cargo door is securely closed and locked some time ago over on the Metropolitan Channel I actually looked at an incident where a freighter's main door opened in flight and this can be extremely dangerous because the structure of the door itself is necessary for the aircraft's fuselage to retain its shape and structural Integrity these Fighters they're not even allowed to be towed unless their cargo door is closed so what NASA had to come up with was a 747 that would not only fly with huge door open but one that could do so at Cruise altitudes would add any effect on its structural Integrity or its controllability this required substantial strengthening of the aircraft's fuselage pictures of the Sophia aircraft show while lap this framework around the door to take up the strength of the missing material obviously this also meant that DLR had to design the telescope to be able to work while getting subjected to huge aerodynamic loads in this unique setup and that was on top of the requirements to stabilize the telescope well enough to be able to actually use it as well part of the telescope was also designed to turn and go through the new rear pressure ball cap and disallowed the scientists on board to make their observations while the aircraft was still Airborne as for actually flying the aircraft well according to NASA it flew and handled just like any other 747 the crew didn't notice any appreciable differences in handling when the door was open or closed and that says a lot about the size and the sign of the 747 but it also says something about the hard work that NASA and its Partners did before fitting the telescope NASA tested multiple types of wind fences and contoured surfaces both to keep the plane controllable and to minimize aerodynamic loads on the sensitive telescope before it was put into operation but sadly All Good Things mods come to an end and Sophia has now flown its last ever space observation Mission the news that this was going to happen came last April with the final flight taking place between the 28th and the 29th of September this year 2022. the pilots and the rest of the crew went out on a high literally with the 45 year old plane cruising as high as flight level four five zero forty five thousand feet before landing back at their base in Palmdale California NASA and the LR decided to retire this remarkable aircraft and its equipment because in their words Sophia's science productivity does not justify its operating costs it is likely that another reason for stopping the program is the recent successes of another NASA program the James Webb Space Telescope both Sophia and James Webb are infrared telescopes but James Webb has a much bigger effective mirror at 6.5 meters or 21 feet and of course being in space and in cryogenic temperatures gives James Webb an even greater advantage but this might not be the end of Sophia or similar aircraft-based telescope yet unlike the Hubble Space Telescope James Webb is in an orbit a long way away from Earth so NASA doesn't expect to be able to service it if everything goes to plan and a lot of work has gone into ensuring that it does James Webb's onboard fuel that it needs to stay in the right orbit will last for at least 10 years and hopefully a bit more than that but after this the future is a little bit less sure a small but interesting tidbit here is the difference in weight between these different telescopes the James Webb Telescope weighed around 6.2 tons or 13 and a half thousand pounds during launch dlr's telescope for Sofia even though it had a much smaller mirror weighed just over 17 tons or 37 000 pounds now this difference in weight is partially because dlr's telescope is designed to be modular so that scientists can fit it with different instruments for different missions so then at least in theory a platform like the Sofia aircraft is much more versatile and upgradable than a Space Telescope is even if it can't hope to be as capable as the James Webb Space Telescope so in the end after very long development period and modifications that included new avionics for the aircraft Sophia became fully operational back in 2014. this means that at its retirement it had spent a bit over eight years in service in this time Sophia's research team studied the atmosphere of distant planets it detected molecular water on the surface of the Moon it studied the formation of distant nebulas the effect of gigantic magnetic fields around black holes and further truly amazing stuff in his eight-year service Sophia spent 732 nights in the air studying the sky in both Northern and the southern hemispheres so what happens next for Sofia well as far as we know it hasn't flown at all since the last mission in September hopefully it will find its way into deserved retirement in a museum which is what NASA is working towards at the moment unless of course which is what I'm hoping for someone at Nasa decides to store it in case it finds a new mission for a giant 747 with a big telescope attached that's for this video guys expect more 747 videos in the coming weeks as we're getting closer to the delivery of the last ever 747 and the end of the production of these iconic aircraft make sure that you've subscribed to the channel so you don't miss anything and if you want to support our work 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Channel: Mentour Now!

Views: 222,597

Keywords: boeing, 747, SP, boeing sp, SOFIA, telescope, step, mentour

Id: DKDz9wS1oWQ

Length: 16min 48sec (1008 seconds)

Published: Thu Oct 27 2022