Orbital to Debut New Minotaur Variant

Minotaur I launch. (Credit: NASA)
Minotaur I launch. (Credit: NASA)

Orbital Sciences will debut a new variant of its Minotaur small satellite launch vehicle in late 2015 with the launch of six Skybox Imaging satellites, the company announced last week.

“The Minotaur-C rocket will use four solid rocket motors supplied by ATK as its propulsion system, all of which have been flown dozens of times and thoroughly flight-proven in various combinations on Orbital’s other small space launch vehicles, including Pegasus, Taurus and Minotaur, as well as on the company’s Orbital Boost Vehicle (OBV) long-range missile defense interceptor,” the company said in a press release.

“It will also incorporate numerous design features that are common with the Minotaur product line, such as the rocket’s electrical power system, payload fairing, flight termination system, navigation sensors and RF components. In addition, the Minotaur-C will utilize its SkySat satellite dispenser, currently in design by the Minotaur team, which will be built and tested at the company’s Chandler, AZ launch vehicle design and engineering facility.”

The currently line of Minotaur launch vehicles primarily uses engines left over from the Minuteman II and Peacekeeper ballistic missile programs. These rockets includes components and systems from the company’s Pegasus and Taurus launch vehicles.

The Minotaur-C will launch six high-resolution imaging and video-capable spacecraft into low-Earth orbit from Vandenberg Air Force Base in California in late 2015. Terms of the agreement with Skybox Imaging were not released.

“We are very pleased to have been selected by Skybox Imaging for this exciting opportunity,” said Mr. David W. Thompson, Orbital’s Chairman and Chief Executive Officer, in a press release. “As fellow participants in the expansion of the commercial space industry, Orbital and Skybox share similar values of innovation, affordability and reliability, which make this partnership a perfect fit. We have offered options for additional launch services to support the development of Skybox’s business, and we are looking forward to the opportunity to forge a long-term, multi-launch relationship with their team.”

  • Bojan Pecnik

    Solids? Really? W/ launch in 2016?

    Why? What is the point of building a new launcher which can not even conceptually compete (performance- AND cost-wise) w/ current state of the art?

    Why would anyone sane invest in such an endeavor?

  • Hug Doug

    The main advantage of solid rocket motors is that they pack a lot of thrust in a small volume. solid rocket motors in general are simple and reliable, and can be easily stored for long periods of time.

    implying that they are not state of the art is incorrect.

    it helps to know a bit of history about the Minotaur rocket – they are derived from Minuteman and Peacekeeper ICBMs, so the solid stages are known to be reliable. this reduces the risk of a launch failure. also they can be stacked in various configurations to provide specific amounts of thrust.

  • Snofru Chufu

    Solid rocket reliability is similar to that of liquid rockets one. No major differences. Use of solid rockets for civil space launch makes in our times no sense more. Their usage helps defence companies to sustain its ICBM production capability.

  • Hug Doug

    “The main advantage of solid rocket motors is that they pack a lot of thrust in a small volume.”

  • windbourne

    yeah, but so what?
    the real issue is really not about lift capability (we can get plenty over the next 10 years), but about economics.
    Are solid motors cheap?
    I do not think so.

  • Snofru Chufu

    Hey Hug
    Doug, the high-thrust potential is only advantageous for missiles but not for space launchers. What you might mean is the impulse density of solid rocket propellant. It is quite high. However, in terms of delta-v it cannot compensate much lower Isp of solid rockets.

  • Hug Doug

    The “so what” is that this means you can have a smaller, more aerodynamic rocket with the same thrust.

    Yes, solid rocket motors are cheaper. Solid rockets are much, much simpler than liquid rockets since they have virtually no moving parts (no pumps, engines, etc). You probably think solid rocket engines are not cheaper because of the Shuttle’s SRBs. The fact is that reusing the casings made them more expensive. If they had been used as a throw-away design, they would have been cheaper.

  • Hug Doug

    Solid propellants have lower specific impulse, but are much more dense, packing more than twice the energy in the same volume as liquid H2 and O2.

  • Snofru Chufu

    You clearly not a rocket scientist! 🙂 You did not understand my comment above. Higher propellant loading in case of existing solid propellant cannot compensate for lower Isp, esp. if compared to LH2/LOX. Do the maths! You have also to see that the complete solid rocket charge is burned under high pressure conditions, which overcompensates weigth saving sfrom not required components as turbopumps or so.

  • Hug Doug

    I understood your comment perfectly, which should be obvious given that I corrected your statement.

    I’m aware of the tradeoffs, and so is everyone else who builds solid-fuel, Kerosene, Propane, etc. fueled rockets instead of just using H2 and LOX. The ISP – energy density tradeoff doesn’t make much sense in a vacuum, otherwise, it does. The higher energy density is why denser fuels are often used in rockets, particularly in first stages.

  • windbourne

    interesting. If the solid motors are cheaper than engines, esp. those that are re-usable, then this would stand a chance.

  • Pete Zaitcev

    Firstly, the current state of the art for small launchers is solid, strately as it sounds. Some may be so used to the idea that solids are dumb in the medium class launchers that they forget the failure of Falcon 1. But the small launcher market is characterized by extremely low flight rate. At that rate, all the market advantages we associate with liquid propulsion are minimized. And the specific impulse of modern solids is amazing. For example, it’s much better than that of cheap liquid engines (such as RD-107, powering Soyuz).

    Secondly, all this effort is merely a redressing of Taurus, which fell out of favour with customers due to embarrassing failures back-to-back. The rocket is Taurus, merely with fairing of Minotaur. Most significant is probably the internal rearrangement at Orbital, decimating the team that launched Taurus and giving this “new” Minotaur to people who launch other Minotaurs. This two-pronged approach helped them to secure a risk-loving customer.

  • Hug Doug

    A lot depends on a major unknown, and that’s the cost or refurbishment. Both the Shuttle SSMEs and SRBs cost way more in refurbishment than anyone expected.

  • Snofru Chufu

    SSME and SRM/SRN shall be not compared. SSME is an extreme example of sophisticated and demanding LRE (overdesigned) technology, which should be not compared to standard robust solid rocket technology as the shuttle SRM was. Also the “retrieval” situation was very different (attached to craft versus fishing from ocean). Better is to compare first stage of Falcon 9 versus Ariane 5 SRM booster.

  • Hug Doug

    oh, it shall not? whatever you say, all-knowing and all-mighty master of everything.