SALVO Cubesat Rocket Debuts Stealth Launch Vehicle Era

The Defense Advanced Research Projects Agency (DARPA) and the U.S. Air Force are poised to begin the Cape Canaveral launch of Cubesats on a new advanced technology rocket called SALVO, for Small Air Launch Vehicle to Orbit. SALVO launchers will be carried aloft for release from an Air Force F-15E fighter jet flying over the U.S Eastern Test Range.

It is possible that the actual launch to orbit of Cubesat spacecraft on SALVO rockets has already begun in secret to counter electronic and infrared intelligence gathering by Russia and China. The flight of a SALVO test article on a F-15 fighter actually began months ago, and likely involved earlier flights over the Eastern Range to checkout telemetry links.

The future air launch of increasingly capable small spacecraft and Cubesats will be especially important as the USAF moves to smaller, more survivable satellites instead of more vulnerable multi-ton spacecraft. The U.S. decades ago developed the F-117 Stealth fighter and the B-2 Stealth bomber, and now programs like SALVO and its ALASA follow on could also give the U.S. a “Stealth Launch Vehicle” capability.

The Orbital ATK Pegasus air launched rocket could be especially important in this Defense Dept. shift, but it is a large and easily detected rocket system requiring significant infrastructure, compared with future smaller air launched systems.

Neither DARPA, the Air Force, nor the project’s prime contractor, Ventions LLC of San Francisco, will discuss SALVO at this time—although in the past they have described it as a two-stage system using liquid oxygen and kerosene propellants driven by cutting-edge miniature electric turbo pumps.

Each SALVO rocket will be loaded onboard its twin seat F-15 at Eglin AFB, located on Florida’s panhandle. Once fueled, it will be flown within a safety corridor across the state directly out over the Atlantic for launch down the highly instrumented Eastern Range.

SALVO can only launch a single 11-pound, three unit (3U) Cubesat at a time, and is designed initially to be only a three-flight operational pathfinder for the larger DARPA/Boeing Airborne Launch Assist Space Access rocket called ALASA.

ALASA is planned to launch 12 times also from an F-15 flying over the Eastern Range. The Boeing system is planned to carry a 100-lb load of Cubesats or small satellites for just $1 million per flight.

ALASA is to be first launched in late-2015 without a payload, then launched on Cubesat missions starting by mid-2016. It will be powered by high energy monopropellant made up of nitrous oxide (aka laughing gas) and acetylene mixed together in the same tank, a key design aspect.

The two DARPA air launched programs could help spawn new commercial air launch ventures like one being developed by Generation Orbit with its GOLauncher 1 & 2 programs, which are set for first launch in 2017 from a Gulfstream business jet.

These will be able to compete in future NASA programs like the just-issued NASA’s Launch Services Program Request for Proposals (RFP) for new commercial Venture Class Launch Services (VCLS) for small satellites. The deadline for a response to the RFP is July 13, 2015.

NASA plans to award one or more firm fixed-price VCLS contracts to accommodate 132 pounds (60 kilograms) of CubeSats in a single launch or two launches carrying 66 pounds (30 kilograms) each. The launch provider will determine the launch location and date, but the launch must occur by April 15, 2018.

“This solicitation, and resulting contract or contracts, is intended to demonstrate a dedicated launch capability for smaller payloads that NASA anticipates it will require on a recurring basis for future science and CubeSat missions,” the agency said.

“This will start to open up viable commercial opportunities,” said Mark Wiese, chief of the flight projects office for the NASA Launch Services Program. “We [NASA KSC] hope to be one of the first customers for these companies, and once we get going, the regular launches will drive the costs down for everyone.”

It is most likely this initial Cubesat launcher contract will be won by one of several traditional ground launch systems like those under development by the Texas-based Firefly Space Systems rocket, the New Zealand based Rocket Lab Electron launch vehicle, or other U.S. competitors.

Air launched systems, although initially carrying a smaller payload mass, would be especially important to the U.S. Defense Dept. because they can be launched from literally anywhere on Earth with minimal detection aloft or by ground infrastructure.

This is especially important now that China’s ASAT anti satellite programs threaten large U.S. satellites. Launching the same type capabilities on multiple distributed satellites makes them harder to destroy and easier to reconstitute, according to USAF Gen. John E. Hyten, who leads Air Force Space Command.

Although prime contractor personnel at Ventions declined to discuss the SALVO rocket, the company’s limited website does cite milestones toward its first SALVO flight, baselined for the current spring 2015 timeframe. The milestones are:

June 2015 – Completed acceptance testing of SALVO 1st stage engines.

April 2015 – Ventions begins cold-flow fill / drain and pressurization tests of SALVO 1st stage.

October 2014 – Ventions ships SALVO test article to Eglin AFB for integration and flight testing with F-15.

July 2014 – Completes aircraft form and fit checks of F-15 aircraft at Eglin AFB.

June 2014 – Completes initial qualification testing of flight-ready injectors for SALVO’s upper stage engine and tests SALVO first stage engine in pump-fed configuration at Merced, Calif., test site.

April 2014 – Ventions tests thrust vector control gimbal for SALVO first stage engines at Merced test site. The company also tests 2nd generation of 1,000lbf regeneratively-cooled, LOX-RP1 engines for SALVO flight vehicle at Merced test site.

February 2014 – Ventions completes 1,000lbf injector screening tests for SALVO flight vehicle at Merced test site.

August 2013 – Ventions initiates hot-fire testing of SALVO injectors and engines using new test cell at Castle Airport in Merced County, Calif.

March 2013 – Ventions hot-fire tests regeneratively-cooled engines in the 75lbf and 800lbf thrust-classes for launch vehicle applications under SALVO program.

February 2013 – Ventions hot-fire tests 75lbf and 800lbf LOX / RP-1 engine injectors for SALVO launch vehicle applications.

While DARPA is entering the SALVO flight test phase, Boeing is completing design details on the 24-ft-long ALASA air launched rocket toward an initial flight late this year.

It uses a unique design, placing its four main engines at the front end of its first stage propellant tank.

That will enable the same engines used in the first stage to also power the second stage, after the first stage propellant tank is depleted and separated. A third stage with four smaller engines would complete the injection into low-Earth orbit.

SALVO is similar to the ASAT program of the 1980s in that it was a rocket on the belly of an F-15, but that is where the similarities end. The 1985 program was not capable of going into orbit, but rather function like an air-to-air missile—more specifically like a sounding rocket with a payload.



The warhead was an ingenious, highly maneuverable IR seeker that would collide to score a kill. It was designed to be launched in front of an approaching satellite given real time NORAD targeting data. SALVO and ALASA as an ASAT are no more similar than an AMRAM or Sidewinder rocket on the belly of a F-15.



The first air launched ASAT tests took place 55 years ago, in 1958-59, with a B-47 bomber during 12 firing tests. The missile was called Bold Orion and in 1959 was fired against the Explorer 6 satellite. It passed within four miles of the satellite, an effective kill range since operationally it would have used a nuke warhead.

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