Orbital Sciences Corporation used their Minotaur IV launch vehicle to loft eight satellites for the United States Government and university research programmes on Friday night. The mission, designated STP S-26, launched from the Kodiak Launch Complex in Alaska one minute into a 90-minute window, with a lift-off time of 20:25 pm Eastern (01:25 UTC).
Minotaur IV Launch:
The primary payload of the STP S-26 mission is STPSat-2, which is a 180-kilogram technology demonstration spacecraft for the USAF Space Test Program. It will conduct two experiments; the Space Phenomenology Experiment (SPEX) and the Ocean Data Telemetry Microsat Link (ODTML), which will investigate operating sensors in space and relaying their data through various media, including the internet.
The Radio Aurora Explorer, or RAX, is a three unit CubeSat, which will be used to conduct studies of the ionosphere, receiving radar signals from ground stations which can be used to measure activity in the ionosphere. It was constructed by, and will be operated by, the University of Michigan and SRI International.
One of several NASA payloads aboard the Minotaur, Organism/Organic Exposure to Orbital Stresses or O/OREOS, is another three unit CubeSat. O/OREOS was designed, built and is managed by NASA’s Ames Research Center, Moffett Field, California – and has a mass of around five kilograms. It carries two biological experiments, one of which will test live microorganisms, whilst the other will test inanimate organic samples, in order to see how they react to conditions in space such as radiation and extreme temperature.
It will also test the use of deployable Mylar panels to increase its rate of orbital decay, and reducing the amount of time it remains in orbit as debris.
The Fast Affordable Science and Technology Satellite, or FASTSAT, is another NASA mission, which is being conducted in association with the University of Texas. It is a 140 kilogram microsatellite, which is expected to operate for 180 days. It will test a Threat Detection System and a Miniature Star Tracker for the US Air Force Research Laboratory.
Three atmospheric experiments are also being carried aboard the satellite; the Thermosphere Temperature Imager, TTI, will measure the temperature of the Earth’s thermosphere, and study the densities of oxygen and nitrogen there. The Miniature Imager for Neutral Ionosphere Atoms and Magnetospheric Electrons, or MINI-ME, will study plasma in the outer atmosphere, and the Plasma and Impedance Spectrum Analyzer or PISA will investigate electrons in the ionosphere, and attempt to demonstrate a new technique for measuring their temperature and density.
In addition to its own experiments, FASTSAT will also carry and deploy another satellite, NanoSail-D2, which will be released seven days after launch. Originally built as a ground spare, NanoSail-D2 will replace the NanoSail-D spacecraft which was lost in a launch failure in 2008. The Falcon 1 rocket which was to have deployed it failed to achieve orbit after residual thrust caused the spent first stage to collide with the second stage, throwing the vehicle off course. NanoSail-D2 is expected to remain in orbit for around 100 days.
Three days after deploying from FASTSAT, NanoSail-D2 will deploy its solar sail, a process which is expected to take five seconds. The spacecraft will use an S-Band transponder to communicate with Earth, and also carries a beacon broadcasting at 437.270 MHz. These will be activated before separation from FASTSAT, and are expected to operate until the spacecraft runs out of power, which will probably happen around 12 days after launch. NanoSail-D2 is a three-unit CubeSat, measuring 30cm by 10cm by 10cm, and will deploy a solar sail with an area of ten square metres.
FalconSat-5 will be the fifth in a series of technology demonstration satellites built and operated by the US Air Force Academy. It carries four experiments; the Space Plasma Characterization Source (SPCS) will use a cold gas ammonia thruster and a Hall Effect ion thruster to study their effects on the space environment.
The Hall Effect thruster will serve as an ion source for the Wafer-Integrated Spectrometer, or WISPERS, which will be used to compare its plume to theoretical data. The Smart Miniaturized Electrostatic Analyzer or SmartMESA will study the temperature and ion density of the ionosphere. It will replace an instrument originally flown on FalconSat-2, which was unable to achieve orbit when the Falcon 1 failed on its maiden flight, and despite the payload being recovered intact it could not be reflown. The final experiment, Receiver UHF/VHF Signal Strength or RUSS, will study the effects of the ionosphere on radio signals.
Formation Autonomy Spacecraft with Thrust, Relnav, Attitude and Crosslink, or FASTRAC, consists of two satellites which will be launched together. The spacecraft were built and will be operated by the University of Texas. The first has been named “Sara-Lily”, and the second “Emma”, both after the children of engineers working on the programme. Sara-Lily will study the use of a Micro-Discharge Plasma Thruster (MDPT) for formation flying with Emma. It will also carry a GPS navigation experiment. Emma will carry an Inertial Measurement Unit, or IMU, which will be used to determine the distance between the two satellites.
The basic Minotaur IV is a four stage all-solid expendable launch system derived from the LGM-118A Peacekeeper missile, which began undergoing development in the late 1970s as a replacement for the Titan II. The Peacekeeper first flew in 1983, entered service in 1986, and remained operational until its retirement in 2005 as mandated in the START-II treaty. Fifty one were launched, of which two failed, out of a production run of 114 built. Two further examples have since been flown as Minotaur IVs.
The first three stages of the Minotaur IV are essentially unmodified Peacekeeper stages. The first stage is a Thiokol-built SR118, the second an Aerojet SR119, and the third a Hercules Incorporated SR120. The fourth stage is an Orion 38, also manufactured by Hercules. On this flight, the rocket will fly with an additional upper stage; a Hydrazine Auxiliary Propulsion System, which is a liquid monopropellant fifth stage, fuelled by hydrazine, and powered by three MR-107K engines.
Despite its presence on the rocket, the HAPS will not contribute in any way to the deployment of the spacecraft. It will not even separate from the fourth stage, let alone ignite, until three minutes after the last payload has separated. It will instead be used to place two mass simulators into a circular orbit at an altitude of around 1,200 kilometres, in order to test the Minotaur’s ability to deploy multiple spacecraft into different orbits. HAPS upper stages have been used on Pegasus rockets before, however this is the first time one has flown on a Minotaur. Eight have previously been launched, two on the original Pegasus, and six on the Pegasus-XL.
The Minotaur IV is part of the Minotaur family of rockets operated by Orbital Sciences Corporation. It was developed as part of the Orbital Suborbital Program II (OSP-2), and is only available to launch US Government payloads due to laws governing the use of components provided by the US military, namely the Peacekeeper missile.
This is the third flight of the Minotaur IV, which made its maiden flight earlier this year carrying the HTV-2a hypersonic flight experiment on a suborbital trajectory. This was followed by the first orbital launch in September, which deployed USA-216, the first Space Based Space Surveillance satellite. This will be the nineteenth launch of a Minotaur in any configuration.
When the countdown reaches T-0, the first stage will ignite, and the Minotaur IV will begin its journey into orbit. Thirty five seconds into the flight the vehicle experience the area of maximum dynamic pressure, or max-Q. Fifty seven seconds after launch, the first stage will burn out and separate, and the second stage will ignite. The second stage will burn for fifty nine seconds, before separating. The third stage will then ignite, and twenty four seconds later the payload fairing will separate from around the spacecraft. The third stage burn will last 72 seconds, and following this the rocket will coast for over ten minutes.
Thirteen minutes and twenty one seconds after launch, the third stage will separate, and eleven seconds later the fourth stage will ignite for a sixty seven second burn. Once the fourth stage has burned out, payload separations will begin. STPSat-2, the primary payload, will be the first to separate and will do so sixteen minutes and thirty nine seconds into the mission. One minute later, RAX will be ejected from a PPod CubeSat dispenser at the rear of the fourth stage, followed a minute later by O/OREOS from another rear-mounted dispenser.
About a minute after O/OREOS separates, the fourth stage will make a 180 degree turn, in order to deploy FASTSAT against the direction of flight. FASTSAT will separate two minutes later, and a minute after that the fourth stage will manoeuvre to an attitude offset from its direction of flight by 150 degrees, and aligned with the elevation of its velocity vector. Four minutes later, FalconSat-5 will separate from the rocket, followed five minutes later by both FASTRAC satellites, which will be deployed together as one spacecraft. Thirty seconds later the rocket will manoeuvre back to align with its direction of flight, and 150 seconds later the HAPS will separate from the fourth stage.
The HAPS will ignite for its first burn one minute after separating from the fourth stage. This first burn will last two minutes and sixteen seconds, placing it into a transfer orbit. Specific times for the remaining flight events have not been given, however the first burn will be followed by a coast phase, lasting approximately fifty minutes. Following this, the HAPS will make a second burn, lasting around three minutes. About three minutes after that burn is complete, the mass simulators will separate from the HAPS. Around seven minutes after the mass simulators have separated, the HAPS will perform either a propellant dump or a depletion burn, and four minutes later it will perform a similar event with its reaction control system, completing the mission.
The target orbit for the deployment of the satellites is a circular low Earth orbit at an altitude of 650 kilometres, and with 72 degrees of inclination. The HAPS and its mass demonstrators are expected to end up in a higher orbit; the target is a circular orbit at an altitude of 1,200 kilometres, however part of the mission is to determine how high it can get. The HAPS burns are not expected to affect the orbit’s inclination.
The launch will take place from Launch Pad 1 of the Kodiak Launch Complex in Alaska. LP-1 is the only launch pad at the Kodiak Launch Complex, a commercial spaceport operated by the Alaska Aerospace Corporation.
This is only the second orbital launch to take place from Kodiak, the first being the “Kodiak Star” mission, which saw an Athena I deploy four satellites in September 2001. At the time, it was the final flight of an Athena rocket; however the type was placed back into production earlier this year with Kodiak expected to support some of its launches. The facility has also been used for suborbital launches, including two AITs, two Ares, and eight STARS rockets.
The next launch of a Minotaur IV is expected to occur in the first quarter of next year, with the TacSat-4 spacecraft for the US Naval Research Laboratory. That launch will also take place from Kodiak Island, and will be the first flight of the Minotaur IV+ configuration with a more powerful fourth stage. Also early next year, a Minotaur IV Lite will launch from Vandenberg with the suborbital HTV-2b mission.