rockets: single stage to orbit

from wiki: Atlas was unusual in its use of balloon tanks for fuel, made of very thin stainless steel with minimal or no rigid support structures. Pressure in the tanks provides the structural rigidity required for flight. An Atlas rocket would collapse under its own weight if not kept pressurized, and had to have 5 psi (34 kPa) nitrogen in the tank even when not fuelled. The only other known use of balloon tanks at the time of writing is the Centaur high-energy upper stage, although some rockets (such as the Falcon series) use partially pressure-supported tanks.

Atlas also had a staging system different from most multistage rockets, which drop both engines and fuel tanks simultaneously, before firing the next stage's engines. Atlas ignites all three of its engines at launch; the booster engines would be discarded, while the sustainer continued to burn.

Rockets using this technique are sometimes called "stage-and-a-half" boosters. This is made possible by the extremely light weight of the balloon tanks. The tanks make up such a small percentage of the total booster weight that the weight penalty of lifting them to orbit is less than the technical and weight penalty required to throw half of them away mid-flight.

Atlas D weighed 255,950 lb (without payload) and had an empty weight of only 11,894 lb, the other 95.35% was propellant. Dropping the 6,720 lb booster engine and fairing reduced the dry weight to 5,174 lb, a mere 2.02% of the initial gross weight of the vehicle (still excluding payload). This very low dry weight allowed Atlas D to send its thermonuclear warhead to ranges as great as 9,000 miles (14,500 km) or orbit payloads without an upper stage.

Close Air Support with heavy bombers

fta:
during a Senate hearing last year, Sen. John McCain pushed back hard on Secretary of the Air Force Deborah Lee James’s description of the B-1 as an effective airplane for “close air support,” or the delivery of precision-guided bombs in support of embattled ground troops. “That’s a remarkable statement,” McCain scoffed. “That doesn’t comport with any experience I’ve ever had, nor anyone I know has ever had.”

What McCain didn’t seem to be aware of, and what the Times report failed to note, is the long third act of the B-1’s life. Converted in the 1990s from a Soviet-airspace-penetrating nuclear strike plane to a conventional bomber meant to pound the infrastructure and massed formations of an enemy army, the “Bone” converted again in the aftermath of September 11, 2001, into exactly what the Arizona senator found so hard to believe: not just a close air support plane, but, by all accounts, a hugely successful one.

One need only watch this video below of a B-1 strike in Afghanistan’s ultra-violent Pech valley, and listen to the profanity-laden commentary of the ground troops doing the filming, to get a sense of the role the big bomber played supporting troops in contact in both Iraq and Afghanistan. In the video, originally uploaded to YouTube by a military spokesperson, troops at a remote firebase watch as three satellite-guided bombs from a B-1 strike mountainside targets almost simultaneously, followed seconds later by a fourth. The soldiers express their elation in not-safe-for-civilian-work terms.

By the time of the airstrike depicted in the video, Bone-drivers had been flying their dark gray planes 20,000 feet over Afghanistan for years — since the opening night of the U.S.-led air war in October 2001, when five B-1s flying out of the Indian Ocean outpost of Diego Garcia joined ten B-52s and two B-2 stealth bombers in pummeling the Taliban regime’s few fixed-site targets.

In the years that followed, the B-1 became a mainstay of close air support and other strike missions over both Afghanistan and Iraq, where a B-1 kicked off the air war in 2003 with a string of bombs meant to kill Saddam Hussein in one of his Baghdad palaces (he wasn’t there). “We are using it in ways never conceived of previously,” secretary of the Air Force James Roche said of the B-1 later that year.

Capable of flying in rougher weather than the B-52, cheaper to operate, and capable of carrying more bombs, in 2006 the B-1 displaced the B-52 and became the standard bomber deployed to support ground troops in the two wars, while the older aircraft played the traditional nuclear deterrent role.

One unit whose veterans sing the B-1’s praises is the 2nd Battalion, 503rd Infantry Regiment, which, during 15 months in the Pech and adjoining Afghan valleys in 2007-8, became the most heavily decorated Army battalion of the post-September 11 wars. “Our favorite asset at the company level was the B-1,” said one of the unit’s company commanders, Lou Frketic. “They had more ordnance and longer loiter times, and they delivered ordnance to the desired location without trying to second-guess us with their own optics.”

“What I loved about the B-1 was that it had such incredible payload capacity and such incredible time on station,” the battalion’s fire support officer, Jeffrey Pickler, agreed. “We dropped over a million pounds of Air Force bombs, and a lot of that was B-1s.” When insurgents attacked from rock formations high in the mountains, artillery and mortars would respond first, trying to get the enemy to take cover; then bombs from a B-1 or another airplane would smash the militants’ natural bunkers before attack helicopters arrived to pick off survivors.

On one of the worst of many bad nights in the battalion’s deployment — Oct. 25, 2007, when a sharp firefight in the Korengal valley left two paratroopers dead and earned one wounded soldier the first Medal of Honor awarded to living recipient since Vietnam — it was a B-1 whose bombs shook the battle-scarred ridge, pounding the escaping insurgents.

https://www.washingtonpost.com/news/checkpoint/wp/2015/12/30/the-under-appreciated-workhorse-of-americas-air-wars-the-b-1-bomber/

Some other good links:

http://www.nytimes.com/2014/07/10/us/politics/at-27000-feet-an-air-force-plea-to-preserve-its-bomber-fleet.html

http://breakingdefense.com/2014/05/sen-mccain-b-1s-really-do-cas/

http://defensetech.org/2014/02/21/air-force-begins-massive-b-1b-overhaul/

Close air support via precision munitions dropped from heavy bombers with long loiter time are the future and the Air Force has been investing in this for a long time.

http://www.airforcemag.com/MagazineArchive/Pages/2012/April%202012/0412lancer.aspx

The Challenger Disaster movie (2013)

The projected cost in US dollars of running the space program kept rising. And knowing this is unsustainable, NASA needs to prove itself, needs to bolster its purpose, over and above civilian scientific research and discovery.

The Air Force, meanwhile, wants to upgrade Titan. An efficient fleet of unmanned rockets to deploy spy satellites into space.

NASA approaches Congress with a deal that seems to make great economic sense, the government can stop funding Titan and instead divert the money to NASA, and the Shuttle becomes sole access into space.

NASA knocks out the Air Force and gets a funding boost. And the Shuttle secures its raison d'etre.

And NASA convinced Congress that by 1986 they'd be able to launch twice a month, every month, and on each of these flights, payload will be made available to the Department of Defense.

But NASA reneges on its obligation and instead of giving DoD priority, they started taking Senators up there, in PR stunt after PR stunt.

And then, launches start getting cancelled.

The press is beginning to notice...

Congress is getting jumpy.

And the administration is asking questions.

And then last December, the launch is delayed six times, and remember NASA had promised Congress launch at any time, under any conditions, and then January 28th, January 28th launch, it's cold, it's very cold but NASA feels under extreme pressure.

And took the risk.

F-35 avionics

Some of the known capabilities of the F-35's systems:

AESA RADAR (A2A, A2G, SAR, MTI, EW), EOTS, EO-DAS, CNI.

The APG-81 comes with a synthetic aperture radar (SAR) terrain mapping function for air-to-surface surveillance and targeting. It is comparable to the terrain mapping radar used in reconnaissance aircraft, unmanned air vehicles, and the E-8C Joint Surveillance Target Attack Radar System (Joint STARS) aircraft.

The F-35 pilot can select from the radar's many software-driven modes: target identification and tracking, air-to-air, air-to-ground, air-to-sea surface target detection and electronic warfare, as well as SAR ground mapping. It can designate both ground targets and airborne targets simultaneously. Being a pulse Doppler radar, the APG-81 can eliminate background clutter regardless of the target environment.

Another mode is the "inverse SAR" mode used to detect and identify surface vessels at sea. As the name implies, it works opposite the SAR mode, in which the radar software forms a composite picture of a ground target based on the movement of the aircraft. Rather, the inverse SAR mode "forms a composite picture of a ship based on the vessel's motion on the sea," Porter explains.

For air-to-air operations, the APG-81 will support such features as passive search, multi-target, and beyond-visual-range tracking and targeting. It also will support a cued search feature, in which the radar is cued toward another sensor's line of sight. That other sensor can be onboard, offboard or pilot-directed. Because the radar beam can move from point to point in millionths of a second, the F-35 pilot can view a single target as many as 15 times a second.

Electronic Attack

Advanced electronic warfare (EW) capabilities enable F-35 pilots to locate and track enemy forces, jam radars and disrupt attacks with unparalleled effectiveness. Advanced avionics give the pilot real-time access to battle space information with 360-degree coverage and an unparalleled ability to dominate the tactical environment. Data collected by sensors on the F-35 will immediately be shared with commanders at sea, in the air or on the ground, providing an instantaneous, high-fidelity view of ongoing operations – making the F-35 a formidable force multiplier while enhancing coalition operations. This system allows F-35 pilots to reach well-defended targets and suppress enemy radars.

Much of the F-35’s electronic warfare and ISR capabilities are made possible by a core processor that can perform more than 400 billion operations per second. This core processor collects data from the classified electronic warfare suite, developed by BAE Systems, to identify enemy radar and electronic warfare emissions and, as happens with the eight sensor Electro-Optical Targeting System (EOTS) providing the pilot 360-degree coverage, recommending which target to attack and whether he or she should use either kinetic or electronic means to counter or negate the threat.

The AN/AAQ-37 electro-optical Distributed Aperture System (DAS) provides:

Missile detection and tracking

Launch point detection

Situational awareness IRST & cueing

Weapons support

Day/night navigation

Communication, navigation and identification suite (CNI): 
Northrop Grumman Radio Systems, a San Diego-based business unit of the company's Space Systems Division, is developing a suite of software defined radios (SDRs) designed to provide such functions as beyond-visual-range identification friend or foe, secure voice communications, caution and warning, intercom, and intraflight information sharing among multiple aircraft via a high-speed broadband data link.

The F-35's CNI suite is comparable to the one Northrop Grumman developed for the U.S. Air Force's F/A-22. "However, it has additional functionality driven by changes for network centric warfare and by the fact that the Joint Strike Fighter is a multibranch, multinational program and therefore must satisfy the needs of multiple customers," says Ken Fecteau, director of the F-35 CNI program at Northrop Grumman. "Also, we've been able to reduce the system's weight and power use."

Reduced weight, along with improved supportability, has been achieved by minimizing hardware through an integrated avionics approach. Fewer components result in less aircraft maintenance and smaller logistics tail. To further facilitate maintenance the F-35's CNI suite includes automated fault detection and isolation.

For communications the software radios in the CNI suite include UHF/VHF receivers and Link 16, an L-band networking waveform. It also is designed to accept the Joint Tactical Radio System (JTRS) waveform. The CNI suite will include TACAN navigation and interface with a GPS receiver. An instrument landing system and the GPS-based Joint Precision Approach and Landing System (JPALS) will be part of the CNI package.

Three-dimensional audio algorithms, to direct appropriate audible cues 360 degrees around the pilot are expected to be part of the CNI suite's future growth.

In-Flight Reconfiguration

The communications radios in the CNI are multichannel and multiband, so they can be configured to perform multiple functions simultaneously. The F-35 pilot can reconfigure the radios manually in flight or have them preprogrammed on a cartridge as a mission load. The CNI system's SDRs have the capability for reconfiguration while airborne, which supports dynamic missions and allows recovery from battle damage.

Seven PowerPC processors are plugged into the CNI suite's two 6U racks, which provide redundancy in case one rack is battle damaged. Five of the processors are dedicated to signal and data processing; two other processors serve as interface modules. The two interface modules, one per rack, link the CNI processors with the F-35 integrated core processor. Each processor includes cryptographic algorithms to ensure both voice and data communications security.

In 2004 Northrop Grumman delivered legacy avionics boxes to prime contractor Lockheed Martin for initial flight testing. They included UHF/VHF communication, radar altimeter, intercom, integrated caution and warning, and IFF. The software radios for the CNI, now under development, will be delivered in June 2006 for testing in Lockheed's mission systems integration lab in Fort Worth, says Fecteau. In September 2006 Northrop Grumman plans to deliver a CNI suite for installation in the F-35 program's airborne test bed, a much-modified Boeing 737.

Perhaps the most guarded capability on the F-35 is its automatic target recognition. Lockheed Martin would only say that the aircraft will be continuously processing sensor detections regardless of the orientation (air or ground track). "Some tracks can be easily and rapidly resolved and categorized, while others will require some extensive processing to resolve ambiguities," says a Lockheed official. For automatic target identification, he adds, the F-35 aircrew "will be able to choose target types during the preflight mission planning process." 

http://www.aviationtoday.com/av/military/F-35-Integrated-Sensor-Suite-Lethal-Combination_1145.html#.VfSOrpdvA78

Drones for future air combat

In order to avoid incidents of fratricide, U.S. aircrew preferred to positively establish the identity of any aircraft they attacked, and for all practical purposes, this meant closing to within visual range of their targets where their superior radar and missile ranges were of little value.

By the late 1960s, U.S. forces were taking steps to solve the BVR IFF problem.

The first was enabled by covert exploitation of Soviet SRO-2 IFF transponder equipment recovered by the Israelis from MiGs shot down during the 1967 Six-Day War. In 1968 the USAF started a program known as Combat Tree to build and incorporate a suitable SRO-02 interrogator into U.S. fighters. By 1971 a suitable system had been designed, tested, and fitted to a number of USAF F-4D aircraft. Known officially as the AN/APX-81, the system could be used in a passive mode where it received and processed IFF replies sent from MiGs in response to their own Ground Controlled Intercept (GCI) radar interrogations, or it could be used in active mode to trigger the MiGs response. A Combat Tree-equipped F-4 could positively identify enemy aircraft at up to 60 nm, three times farther than the F-4 could detect, but not identify, them with its radar alone.

A second USAF initiative to enhance long-range target identification was the inclusion of the AN/ASX-1 Target Identification System Electro-Optical (TISEO) system on upgraded versions of the F-4E. TISEO was a stabilized telescope integrated with a TV camera attached to the inboard section of the F-4E’s left wing (see Figure 9) that displayed images on the back-seater’s radar scope. It had several operating modes, including one where the camera was slaved to the radar, allowing the crew to identify a target the radar was tracking, and another where the camera searched a volume of sky for possible targets. It could also automatically track targets once they were located. TISEO gave F-4E crews the ability to identify large aircraft at 50 to 80 nm and fighter-size aircraft at 10 nm or more.

F-4E crews equipped with Combat Tree and TISEO were much more likely to detect and identify enemy aircraft at long range where they could effectively employ their BVR weapons than were U.S. pilots through most of the Vietnam War. The USAF also incorporated a host of lessons from aerial combat over Vietnam into the requirements for their new dedicated, as opposed to the multirole F-4, air-to-air fighter: the F-15.

One of the many innovations the F-15 introduced was Non-Cooperative Target Recognition (NCTR). NCTR compares prominent features from radar returns (e.g., engine compressor or turbine blades—if visible) with data on friendly and enemy aircraft features and automatically categorizes target returns.

The ability to carry a deep magazine of long-range air-to-air weapons with multiple seeker options will almost certainly be vital to success in future air combat. Many of these attributes are much easier to integrate into large aircraft that have greater space and payload available for sensors, cooling, electrical power, and large, long-range weapons compared to small aircraft the size of traditional fighters.

The prospect that supersonic speed and high maneuverability have much reduced tactical utility suggests it could be possible to build effective combat aircraft with no large vertical tails to facilitate B2/A2 radar low observability. The increased importance of electronic sensors, signature reduction, RF and IR countermeasures and robust LOS networks in building dominant SA, and the potential reduced tactical utility of high speed and maneuverability could mean that, for the first time, the aerial combat lethality of large combat aircraft may be competitive or even superior to more traditional fighter aircraft designs emphasizing speed and maneuverability.

http://issuu.com/csbaonline/docs/csba6110_air_to_air_report?e=15123547/11484803

How tough is the A-10

June 1991

Lt. Gen. Charles A. Horner, Central Air Forces commander, analyzed the performance of Air Force weapons, tactics, and personnel in Operation Desert Storm when he spoke with Richard Mackenzie at USCENTAF headquarters in Riyadh, Saudi Arabia, in March.

Q: Did the war have any effect on the Air Force's view of the A-10?

A: No. People misread that. People were saying that airplanes are too sophisticated and that they wouldn't work in the desert, that you didn't need all this high technology, that simple and reliable was better, and all that.

Well, first of all, complex does not mean unreliable. We're finding that out. For example, you have a watch that uses transistors rather than a spring. It's infinitely more reliable than the windup watch that you had years ago. That's what we're finding in the airplanes.

Those people were always championing the A-10. As the A-10 reaches the end of its life cycle-- and it's approaching that now--it's time to replace it, just like we replace every airplane, including, right now, some early versions of the F-16.

Since the line was discontinued, [the A-10's champions] want to build another A-10 of some kind. The point we were making was that we have F-16s that do the same job.

Then you come to people who have their own reasons-good reasons to them, but they don't necessarily compute to me-who want to hang onto the A-10 because of the gun. Well, the gun's an excellent weapon, but you'll find that most of the tank kills by the A-10 were done with Mavericks and bombs. So the idea that the gun is the absolute wonder of the world is not true.

Q: This conflict has shown that?

A: It shows that the gun has a lot of utility, which we always knew, but it isn't the principal tank-killer on the A-10. The [Imaging Infrared] Maverick is the big hero there. That was used by the A-10s and the F-16s very, very effectively in places like Khafji.

The other problem is that the A-10 is vulnerable to hits because its speed is limited. It's a function of thrust, it's not a function of anything else. We had a lot of A-10s take a lot of ground fire hits. Quite frankly, we pulled the A-10s back from going up around the Republican Guard and kept them on Iraq's [less formidable] front-line units. That's fine if you have a force that allows you to do that. In this case, we had F-16s to go after the Republican Guard.

Q: At what point did you do that?

A: I think I had fourteen airplanes sitting on the ramp having battle damage repaired, and I lost two A-10s in one day [February 15], and I said, "I've had enough of this." It was when we really started to go after the Republican Guard (with F-16s).

http://mackenzieproductions.com/Gen._Horner.html