The Blackbird had two seats onboard. Could it be reactivated for nearspace tourism, placing a paying tourist in the other seat? If no, why not or why isn't it being proposed? In leveled flight, the Blackbird flew up to 90,000 ft (27 km) MSL and faster than Mach 3. In a ballistic parabola it could probably reach an even much higher altitude, and on the parabola's top you'd start to experience weightlessness, go above most of the ozone layer, see a black sky with some stars in daytime and the thin blue atmosphere of Earth. An exceptional experience for many.
$\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$– Farhan ♦Dec 15, 2020 at 19:51
Significant issues with the concept: the SR-71 lacks RCS, so you'd lose attitude control if you got significantly above normal operating height. I originally wrote that it doesn't handle in-flight restarts well, but apparently it has the opposite problem -- it needs them all too frequently in normal operation. It's also not an aircraft built for near-vertical climbs or high-G maneuvers, so a zoom climb is outside its normal operational envelope.
So, you can't demonstrate long (> 1 minute) periods of microgravity without the likelihood of loss of aircraft, crew, and paying passenger. Beyond that, however, there's virtually zero visibility from the rear seat. Who'd pay $100,000 for a "near space experience" with no zero G and no view of the black sky and curved horizon?
Never mind the fact that the SR-71 doesn't run on standard jet fuel (JP-1 or Jet-A); the engines could be retuned to do so, but then wouldn't continue to operate at 80,000 feet ASL or push the aircraft to around Mach 3 at that height -- in other words, it wouldn't do what an SR-71 is famous for doing. And the special fuel the SR-71 requires hasn't been manufactured since the aircraft were retired -- it would probably cost more to restart production of that fuel than you'd make back in a reasonable twenty-year "space tourism" operating life (never mind cost of refurbishing an aircraft, pulling still-classified equipment out of at least the passenger seat, training new pilots -- oh, right, you'd have to refurb one of the trainers, that would at least solve the passenger visibility issue)...
Bottom line: no chance. You'll get a better experience with the Russians; at least they can do a zoom climb and have RCS to point the nose back down so they don't wind up in a flat spin like the one Yeager had back in the day.
1$\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$– FedericoDec 18, 2020 at 16:46
I work and have worked with several SR-71 crew members.
In the past, they have pointed out two principle impediments:
- Crew workload
Crew workload is shared between both crewmembers, and the workflow would need substantial modification and equipment changes to permit the backseater to merely be a passive observer. Not to mention that the backseater really doesn't get much of a view. So aside from crew duties, there would be little experience which would warrant...
The cost, is high for even SR-71 training missions. A friend who flew as the backseater in the NASA SR-71 commented that their cost per flight was 5 to 6 million. Tankers were necessary, and the equipment was not the most reliable. Once when taking their SR-71 to Oshkosh, they were looking at corn tassels while working out a fuel transfer pump problem. The aircraft sat at Milwaukee for a couple of months while repairs were effected so it could be flown home.
Not to mention other endearing attributes of the SR-71. Frequent fliers complain about engine unstarts and the violent head jarring experiences they bring. It is just not economically feasible and lacks a good customer experience. Better options for near-space are available in Russia.
$\begingroup$ Or in Virgin Galactic (SpaceShipTwo) and Blue Origin (New Shepard). There will also be a SpaceX Dragon orbital tourist flight. $\endgroup$– GiovanniDec 15, 2020 at 15:49
6$\begingroup$ Absolutely, however I did not reference those because the Russian option is here today. I think that there is a similar existing option in one of the Eastern European countries as well. $\endgroup$– mongoDec 15, 2020 at 16:01
1$\begingroup$ I think many countries offer flights in fighter jets (including weightless parabolae), the question is just how high they (can) go. As for the Russian one, they state they're the only option for a civilian to break the sound barrier since the end of the Concorde, so in this they're exceptional. I wonder whether you can go above the Armstrong line subsonically in a plane. I should ask this as another question. $\endgroup$– GiovanniDec 15, 2020 at 16:10
1$\begingroup$ VIP flights were done in the SR-71; see e.g. sr71.us/Supp_BBook.htm For the view, perhaps the SR-71B would be the appropriate variant to re-activate if you were going to all that trouble anyway. $\endgroup$ Dec 15, 2020 at 23:30
1$\begingroup$ To your second point of cost - I was in TAC when there was the proposal to retire them the first time. Remember, the Soviet Union was collapsing and Congress was looking for a "peace dividend" so there were big budget cuts coming at the time. I asked a friend who was involved why they were considering retiring the SR-71. His response was that that one SR-71 wing (~20 a/c) cost as much to operate as three F-16 wings (72 a/c each), though that cost included the KC-135Q tanker support. I was surprised when they brought them back when they did. $\endgroup$– GerryDec 16, 2020 at 2:21
Typical SR-71 missions proceeded as follows:
- Fill tanks on ground.
- Tanks leaking fuel like crazy, by design.
- Plane takes off, with fuel leaking everywhere.
- Plane gets to altitude, and flies very fast to heat up.
- One plane is heated, fuel tanks are sealed, but nearly empty. Mid-air refueling required.
- Plane has to fly as slow as possible / near stall, refueling plane has to fly as fast as possible to refuel.
- Once refueled, SR-71 can fly mission.
The above does not include, the extremely high probability of failure for this aircraft, and the very high level of danger.
Aside from all the other logistical issues described by others, it's just not a practical aircraft for anything but top secret missions where the high probability of failure is acceptable, and the crazy amounts of danger are concealable. As a commercial aircraft it would never work. It just has way too many failure modes.
27$\begingroup$ "On a typical SR-71 mission, the airplane took off with only a partial fuel load to reduce stress on the brakes and tires during takeoff and also ensure it could successfully take off should one engine fail. As a result, the SR-71s were typically refueled immediately after takeoff. This has led to the misconception that the plane required immediate refueling after takeoff due to leaking fuel tanks. However, leaks were measured in drips per minute, and were not significant compared to the overall capacity." - Wikipedia $\endgroup$– HerohtarDec 15, 2020 at 20:00
8$\begingroup$ That's interesting. I read first hand accounts 20 years ago, that indicated the leaks were way worse that "drips per minute." $\endgroup$– JohnDec 15, 2020 at 23:24