United Launch Alliance (ULA) launched – at the third attempt – the penultimate Delta II mission on Saturday, carrying the JPSS-1 weather satellite on its path to orbit from Vandenberg Air Force Base in California. Liftoff, from Space Launch Complex 2W, occurred during a 62-second window opening at 01:47 Pacific time (09:47 UTC) on Saturday.



Attempt 1 and 2 Scrubs:

On Tuesday, launch was scrubbed due to a red range issue – noted to be yet another boat wandering into the hazard zone – and a late launch vehicle alarm.

Due to the short window there was insufficient time to fully coordinate a resolution. A 24 hour scrub turnaround was employed.

On Wednesday, the launch countdown was proceeding without issue, including a 100 percent go on the weather. However, the weather conditions are a separate factor to other elements, such as Upper Level winds, which were a concern ahead of the planned T-0.

A weather balloon reported back that these conditions were Red, resulting in a scrub for at least 24 hours. Winds were forecast to be even higher on Thursday, resulting in the next attempt moving Saturday.

Delta II Mission Overview:

JPSS-1, which will be renamed NOAA-20 once it is in orbit, is the newest satellite in the US National Oceanic and Atmospheric Administration’s (NOAA’s) fleet of polar-orbit weather satellites. JPSS-1 is the first of four planned Joint Polar Satellite System (JPSS) spacecraft, successors to the organization’s current-generation Polar Operational Environmental Satellite (POES) constellation.

POES was itself the successor to the United States’ first operational weather satellite program, TIROS.

The first satellite, TIROS 1, was launched by a Thor DM-18 Able II rocket in April 1960. The program was passed from NASA to the Environmental Science Services Administration (ESSA) and then to NOAA upon its formation in 1970.

The first TIROS satellite launched for NOAA was named NOAA-1 after reaching orbit, with subsequent satellites being numbered sequentially after a successful launch. In the event of a launch failure, the number carries over to the next satellite to be flown.

The last POES satellite, NOAA-19, was launched by a Delta II rocket in February 2009. The satellite, which was known as NOAA-N’ before launch – remains in service along with the NOAA-15 and NOAA-18 satellites, which launched in 1998 and 2005 respectively.

The JPSS program grew out of the canceled National Polar-Orbiting Operational Environmental Satellite System, or NPOESS, which aimed to replace the NOAA’s POES system and the Air Force’s Defense Metrological Satellite Program (DMSP) with a single fleet of satellites. NPOESS was abandoned in 2010, with NASA and NOAA continuing to collaborate on a new project that became JPSS, while the Department of Defense pursued the now-abandoned Defense Weather Satellite System (DWSS).

Despite the cancellation of the NPOESS program, the NPOESS Preparatory Project (NPP) pathfinder satellite was launched in October 2011.

Renamed Suomi National Polar-orbiting Partnership, or Suomi NPP, this satellite has helped to bridge the gap between the NOAA’s current and next-generation weather satellites, while also helping to demonstrate new capabilities. JPSS-1 is based on the Suomi satellite.

The 2,540-kilogram (5,600 lb) JPSS-1 satellite was constructed by Ball Aerospace, and is based around the BCP-2000 satellite bus. Expected to operate for seven years, it carries the same suite of five instruments as Suomi.

Its Visible Infrared Imaging Radiometer Suite (VIIRS), images the Earth at twenty-two visible-light and infrared wavelengths. The data it collects will help scientists to monitor a wide range of phenomena on the Earth’s surface and in the atmosphere.

Clouds and the Earth’s Radiant Energy System (CERES) FM6 is the sixth in a series of instruments designed to measure Earth’s radiation budget: the amount of radiation the planet emits and the amount of sunlight that it reflects. CERES instruments have previously flown aboard the Terra and Aqua satellites – which carried two each – and Suomi NPP.

Two atmospheric sounders – the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) – will allow the satellite to build temperature, pressure and humidity profiles of Earth’s atmosphere.

CrIS uses a 1,305-channel Fourier transform spectrometer to take readings at infrared wavelengths, while ATMS has 22 spectral channels and operates at microwave wavelengths. The atmospheric profiles produced by these instruments will aid both weather forecasting and monitoring of changes in the Earth’s climate.

JPSS-1’s Ozone Mapping and Profiler Suite (OPMS) consists of two hyperspectral imagers which will be used to monitor the level and distribution of ozone within the upper atmosphere and troposphere. The instrument will allow NOAA to monitor the recovery of Earth’s ozone layer, as well as helping to forecast ultraviolet radiation levels and to report on air quality.

In addition to JPSS-1, five small satellites were aboard the launch. Four of these were being carried as part of NASA’s Educational Launch of Nanosatellites, or ELaNa, program and the ELaNa XIV mission. ELaNa is a NASA program which provides launch opportunities for mostly university payloads built to the CubeSat standard, a very common specification for nanosatellites.

EagleSat is a single-unit CubeSat which was built by the Embry-Riddle Aeronautical University. The satellite will be used to study how solid-state storage devices are affected by exposure to the radiation environment that spacecraft experience. A GPS receiver aboard the spacecraft will also allow students to track changes in its orbit over time – allowing its orbital decay to be characterized.

Another single-unit CubeSat, MakerSat-0, will study how several polymers used in 3D printing are affected by exposure to space. The satellite is a pathfinder for Northwest Nazarene University’s MakerSat project, which later aims to construct a satellite wholly in space and deploy it from the International Space Station.

Vanderbilt University’s RadFxSat-1 was built in partnership with AMSAT. A single-unit CubeSat, it will be used to investigate how electronic components are affected by radiation in orbit, helping to prove their suitability for future missions and refine their manufacturing processes. The spacecraft also carries an amateur radio transponder for AMSAT, who use the name Fox-1B for the satellite.

The last of the ELaNa payloads, Microwave Radiometer Technology Acceleration, or MiRaTA, was built by the Lincoln Laboratory at the Massachusetts Institute of Technology (MIT).

It is a 5.5-kilogram (12.1 lb), three-unit CubeSat which will carry out a technology demonstration mission.

The satellite carries an ultra-compact microwave radiometer to be tested in orbit, as well as an experimental GPS receiver which will be used to help study the occultation of GPS signals as they pass through the atmosphere – which allows atmospheric conditions to be inferred from how the signals are affected.

MiRaTA will also demonstrate how the measurements from its GPS receiver can be used to calibrate the radiometer.

The final CubeSat aboard the launch is not part of the ELaNa program. The Buccaneer Risk Mitigation Mission (Buccaneer RRM) satellite is a three-unit CubeSat being flown in partnership between the University of New South Wales and the Australian Department of Defence’s Defence Science and Technology Group (DSTG).

The satellite is a prototype, being launched ahead of another satellite – Buccaneer – which will be used to help calibrate Australia’s Jindalee Operational Radar Network (JORN).

The launch marked the penultimate flight for ULA’s veteran Delta II rocket, which served as a workhorse of the US space industry for two decades before its launches began to wind down. Delta II has flown just twice since 2011, with its most recent mission the launch of NASA’s Soil Moisture Active-Passive (SMAP) satellite in January 2015.

The last member of a line of rockets that traces its ancestry back to the Thor intermediate-range ballistic missile (IRBM) and the Vanguard rocket of the 1950s, Delta II has completed 151 successful launches from 153 flights, prior to this mission.

Developed to help the US Air Force re-establish its expendable launch programs after abandoning a transition to NASA’s Space Shuttle, Delta II was a replacement for the pre-Shuttle Delta 2000 and 3000-series rockets.

Delta II first flew in February 1989, with a Delta II 6925 delivered the first operational GPS satellite to orbit. The 6000-series was an interim version of the rocket using Castor-4A boosters – the 7000-series which uses GEM-40s first flew in November 1990.

Delta II’s only launch failure to date occurred in January 1997, thirteen seconds after Delta 241 lifted-off to deploy the GPS-IIR-1 navigation satellite.

The casing of one of the solid rocket motors had been damaged during transport to the launch pad and cracked as the rocket began its flight.

The structural failure of the booster triggered the rocket’s onboard self-destruct, and Delta 241 exploded less than 500 meters (1,600 feet) above its launch pad. An earlier launch had resulted in a partial failure after one of the boosters failed to separate, leaving Koreasat 1 in a lower-than-planned orbit.

The launch lifted off from Space Launch Complex 2W (SLC-2W) at California’s Vandenberg Air Force Base. SLC-2W was originally built as part of a larger complex used for early Thor launches from Vandenberg, and was originally designated Pad 75-1-2 – with the 75 coming from SM-75, the systemic designation of the Thor missile prior to 1962.

The first launch from the pad was made by Britain’s Royal Air Force, testing a Thor DM-18A missile on 17 September 1959. The first orbital launch from LC-75-1-2 was made by a Thor DM-21 rocket with an Agena-D upper stage, carrying a KH-4 reconnaissance satellite, on 29 August 1962.

Today, SLC-2W is the Delta II’s only remaining launch pad following the closure Cape Canaveral’s Space Launch Complex 17B (SLC-17B) in 2011.

Delta rockets are assigned a flight, or “Delta” number, sequentially in the order in which they launch. Assuming the JPSS-1 launch is not sufficiently delayed that a Delta IV mission launches before it, the rocket that will perform this launch will become Delta 378 (D378) at liftoff.

For this mission, Delta II flew in the 7920-10C configuration. Delta was one of the first rockets to adopt a systemic numbering system for different configurations, with the first digit denoting the type of first stage and boosters, the second digit giving the number of solid rocket boosters, the third digit representing the type of second stage and the fourth indicating the type of third stage, if one is present.

The final part of the designation gives the type of payload fairing being used, with the 10C fairing a three-meter (ten-foot) composite model.

The “7000-series” Delta II uses an Extra-Extended Long Tank Thor (XELTT) first stage, with three, four or nine Graphite Epoxy Motor 40 (GEM-40) solid rocket motors.

The launch was the last time Delta flies with nine solid rocket motors – the family’s most common booster configuration since the 1970s.

The XELTT, which is descended from the Thor IRBM, is powered by an RS-27A engine. Two additional vernier motors help to steer the rocket during first stage flight. Delta II’s second stage is a Delta-K, powered by an AJ10-118K engine, while in the 7920 configuration no third stage is present.

Both the first and second stages are liquid-fuelled, with the first stage burning RP-1 propellant oxidized by liquid oxygen and the second stage Aerozine 50 – a mixture in equal parts of hydrazine and unsymmetrical dimethylhydrazine – and dinitrogen tetroxide.

Delta 378 ignited its RS-27A main engine and both verniers 2.7 seconds before the countdown reached zero. At zero, six of the nine GEM-40 solid rocket motors ignited, and Delta lifted off to begin the journey into orbit.

With its six ground-lit solids burning Delta climbed quickly away from Vandenberg, reaching a speed of Mach 1 32.9 seconds after liftoff and passing through the area of maximum dynamic pressure – or max-Q – 14.9 seconds later.

The six solid motors burned for about 64 seconds. The remaining three GEM-40 motors were air-lit and also burned for 64 seconds, igniting about one and a half seconds after the ground-lit solids burned out. The ground-lit solid motors jettisoned about 86 seconds into the flight, with the air-lit motors separating at the 131.5-second mark.

After the solids separate, Delta’s RS-27A engine continued to burn until four minutes, 23.4 seconds after liftoff, when it shut down. This event is designated main engine cutoff, or MECO, and followed shortly afterward by vernier engine cutoff, or VECO. Eight seconds after MECO the first stage was jettisoned, with the second stage’s AJ10 engine ignited five and a half seconds after stage separation, beginning the first of four planned burns.

The first burn of the Delta-K second stage lasted six minutes and 1.3 seconds. About 4.1 seconds into the burn Delta’s payload fairing separated from around JPSS-1 at the nose of the rocket. The first burn established an initial parking orbit, and was followed by a 40-minute, 11.8-second coast phase before the second burn began.

Lasting twenty-four seconds, Delta-K’s second burn circularized the orbit for the primary payload, JPSS-1. Six minutes and 16 seconds after the end of the burn, JPSS-1 separated into its operational orbit.

The target parameters for this launch are a semi-major axis of 7,201.1 kilometers (4,474.6 miles, 3,888.3 nautical miles) and eccentricity of 0.001 – giving an orbit of 822.9 by 837.3 kilometers (511.3 x 520.3 miles, 444.3 x 452.1 nautical miles). This orbit will be inclined at 98.7 degrees, with an argument of perigee of 69.2 degrees.

Separation of the primary payload did not mark the end of this flight – seventeen-and-a-half minutes after spacecraft separation, the Delta-K made its third burn – lasting 10.2 seconds – to adjust its orbit for deployment of the CubeSats.

The three single-unit CubeSats were released six minutes and 29.8 seconds after the end of the burn, with the first of the three-unit satellites separating 120 seconds later and the other and 100 seconds after that.

The fourth and final burn of the Delta-K – beginning 29 minutes and 25 seconds after CubeSat deployment lasted 41 seconds – deorbited the upper stage to a safe, destructive, reentry.

The launch was the only Delta II to launch in 2017, with the rocket’s next launch – its final flight – currently scheduled for next September. The next mission for United Launch Alliance is the planned launch of the National Reconnaissance Office’s NROL-47 mission atop a Delta IV, currently slated for 13 December.

(Images via Derrick Stamos and Philip Sloss for NSF, ULA, Ball Aerospace, Related Cubesat producers and NASA).