Oh don't let the F-35 people know about the space plane role or they're going to add another 30 years and $2 trillion onto that program.
Unmanned U.S. Air Force space plane lands after secret, two-year mission
61–70 of 177 posts
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#62Earlier quoted context omitted.
SpaceX Dragon capsule can't land without atmosphere either it needs it to aerobreak it doesn't carry nearly enough fuel to come to a rest from orbital reentry speeds using propulsion alone.
https://www.quora.com/Can-the-Dragon-V2-land-on-the-moon > The Dragon-2 has enough power and fuel to land and ascend back to lunar orbit. The Dragon's SuperDraco has higher performance than the Apollo Lunar Module. Apollo LM descent engines has 10,000 lbf thrust, and 3,500 lbf thrust for ascent (the lander part is left behind). The Dragon's SuperDraco has 16,000 lbf thrust. The Dragon also uses computers to control t…
That is not accurate.
Estimates are that the Dragon v2 has about 400m/s dV. This is around what it would need for controlled landing or abort. It takes around 1720m/s just to get to the stationary Lunar surface from Lunar orbit; If a Falcon upper stage detaches during the leg of the mission between Earth and Luna, the necessary delta V for the rest of the mission will be around 5080m/s. This is a lot. You would have to build another fairly large vehicle to accomplish this mission - Dragon v2 would be an afterthought.
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#63Earlier quoted context omitted.
SpaceX Dragon capsule can't land without atmosphere either it needs it to aerobreak it doesn't carry nearly enough fuel to come to a rest from orbital reentry speeds using propulsion alone.
https://www.quora.com/Can-the-Dragon-V2-land-on-the-moon > The Dragon-2 has enough power and fuel to land and ascend back to lunar orbit. The Dragon's SuperDraco has higher performance than the Apollo Lunar Module. Apollo LM descent engines has 10,000 lbf thrust, and 3,500 lbf thrust for ascent (the lander part is left behind). The Dragon's SuperDraco has 16,000 lbf thrust. The Dragon also uses computers to control t…
I don't understand how they can conclude that "the Dragon-2 has enough power and fuel to land and ascend back to lunar orbit" based only on a comparison of maximum thrust and a statement that the Dragon has an automated landing system.
At the very least, they'd need to consider the dry weight and fuel load to make a fair comparison - maybe they did so offscreen but it's not mentioned anywhere in the post.
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#64Earlier quoted context omitted.
It's tough to be sneaky in space...
If the satellite has "local" sensing equipment, then sure there's nowhere to hide. How many satellites have that? If such sensors aren't installed, it's not like anyone down here on the ground will notice. If someone did notice, what could they do in response? Complain to the media?
Amateurs have been tracking it [0] and even photographing it [1] while in orbit. Any government that has the capability to send satellites to space can do the same.
[0] http://www.space.com/8470-secret-37b-space-plane-spotted-ama...
[1] https://www.universetoday.com/65338/amateur-astronomer-image...
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#65Surprised nobody's mentioned this possibility as it usually comes up re: the X-37B. Terrifying but I think not out of the question given the strategic potential of such a weapon. https://en.wikipedia.org/wiki/Kinetic_bombardment
People always talk about kinetic strikes in the context of big flashy things like rockets and spaceplanes. I'd be a lot more worried about them being dropped from stratospheric balloons - maybe not so useful for full scale bunker busting but extremely cheap to make and almost indefensible against as a strategic strike system.
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#66Earlier quoted context omitted.
Capsules aren't inferior. In fact they can land on planets and moons without atmospheres, unlike space planes. And once propulsive landing of capsules is implemented, they can land on Earth without a landing strip, and even on boats.
There are a few things that wings can do that capsules cannot. Shuttle's wing were never actually used for their intended purpose. Wings allow for "once over and return" flights. Shuttle's creators envisioned it launching into a polar orbit, overflying the USSR to [redacted] then land back home without a second orbit. That requires the ability to 'fly' through the atmosphere to make up for the earth's rotation during…
The driving requirement of the Shuttle was that it should be feasible to steal a Soviet satellite sporting unknown new orbital technology, before the Soviets had the opportunity to intervene, and that it be prepared to fly fairly quickly whatever its faults to be ready for potential Soviet expansions into spaceflight as an area of competition.
There were a lot of other requirements and stakeholders that were part of the planning process, and any of them who didn't understand that espionage was a critical component were left wondering why anyone would design such an expensive, impractical failure; Why every stage of the process where it seemed to be unworkable, someone said "Yeah, don't worry about that" and poured money on the problem. Aside from direct requirements, we also encouraged the Soviet Union to spend lavishly copying our design.
By the time the USSR unexpectedly broke up, Energia had just (unsuccessfully) flown a test run with a giant Polyus laser weapon. Mission accomplished, right? But we didn't then want all of the Soviet scientists to spread to the winds and start building ICBMs for anyone who could pay. We needed them to stay in Russia until Russia could become a solvent, stable state.
So we said "What sort of international cooperative effort could we use a whole bunch of Shuttle AND Soyuz flights for?" and designed (or adapted) a space station around that requirement. We decided to revamp Reagan's ill-fated "Space Station Freedom" program into the ISS.
That's the only reason we didn't retire the Space Shuttle long before the Columbia.
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#67Earlier quoted context omitted.
Capsules like Soyuz can't land without an atmosphere. They use aerobraking and parachutes. You need a big rocket to slow down and land. At which point it's a very different machine.
SpaceX's Dragon capsules come with engines, which (in some configurations) are sufficient for powered landings. And it's still called a "capsule."
Powered landings after an intense atmospheric deceleration.
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#68Earlier quoted context omitted.
Yea, wings on spacecraft are about as elegant as parachutes. They can make sense for certain uses, but, as a rule of thumb, they are inelegant and not futuristic.
Technically, the space shuttle and this space plane are lifting bodies, which I think is pretty cool and elegant.
There isn't really a sharp distinction, is there? The primary method of generating lift for both wings and lifting bodies is simply the fact that it's an inclined plane moving through a fluid with positive angle of attack.
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#69I like the semi-gibberish official explanation: The orbiters "perform risk reduction, experimentation and concept-of-operations development for reusable space vehicle technologies," the Air Force has said without providing details. The cost of the program is also classified. How, pray tell, does anything "perform risk reduction"? Does that phrase have any meaning in English, or any other terrestrial language? "The co…
Risk reduction is a completely normal term in R&D. It just means experiment to raise confidence in a particular proposed approach, before going full scale production. It is meant to raise the TRL[1] of a technology, to gain experience with it. In my software day job, we write throw away code to test out an idea, and we call it proof of concept. It is used to find out early if the schedule for a feature is too optimis…
Just to add some details to the above well-informed comment:
Sometimes people who are not used to management of large-scale projects are surprised by the development of tools and specialized vocabulary in project cost/schedule/risk assessment. The following is a pretty good summary of some common tools that integrate cost, schedule, and risk analysis: http://www.iceaaonline.com/ready/wp-content/uploads/2015/06/...
See in particular the first couple of slides on motivation, the "risk cube" on pages 19-20, the scatter plots of cost/schedule on pages ~30, and the example "risk lists" on page 57. Project management can be viewed as an assault on the remaining top items of the relevant risk list.
All these concepts are standard practice for large aerospace projects. There will be risk analysts with stats or operations research PhDs running simulations and developing tailored methods just to assess risk of large projects. (Example: https://viterbi.usc.edu/sae/faculty/part-time-lecturers/jair...)
Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission
#70Earlier quoted context omitted.
There are a few things that wings can do that capsules cannot. Shuttle's wing were never actually used for their intended purpose. Wings allow for "once over and return" flights. Shuttle's creators envisioned it launching into a polar orbit, overflying the USSR to [redacted] then land back home without a second orbit. That requires the ability to 'fly' through the atmosphere to make up for the earth's rotation during…
The driving requirement of the Shuttle was that it should be feasible to steal a Soviet satellite sporting unknown new orbital technology, before the Soviets had the opportunity to intervene, and that it be prepared to fly fairly quickly whatever its faults to be ready for potential Soviet expansions into spaceflight as an area of competition. There were a lot of other requirements and stakeholders that were part of…
Nobody seriously though Shuttle could bring back a hostile spacecraft. The logistics of such a thing are ridiculous. What Shuttle could have done was to bring back friendly sats. The only friendly sats worth bringing back would be something that couldn't be allowed to re-enter. The only things that couldn't ever be allowed to re-enter would be something nuclear, either a reactor or a bomb. Shuttle was envisioned as a system for maintaining some sort of nuclear tech in orbit. That never happened, but the worry that it would was a driving force behind Buran.