Vega launcher to orbit five satellites on its seventh mission
Arianespace is gearing up for the seventh launch of the Vega rocket in its series, which will place into orbit PerúSAT-1 and four SkySat satellites. The launcher is scheduled to lift off from the Vega Launch Complex (SLV) in Kourou, French Guiana, at 10:43 p.m. local time on Sept. 15 (9:43 p.m. EDT; 1:43 GMT on Sept. 16).
The mission, designated VV07, will carry a total payload of approximately 1.23 metric tons. The flight, lasting approximately one hour and 43 minutes, will result in the insertion of the satellites into an elliptical low-Earth orbit (LEO).
The mission campaign started in June with the assembly of the Vega launcher. The teams were busy throughout the month to integrate all four stages of the rocket. After the assembly of the launch vehicle, the engineers conducted the synthesis control test.
The satellites arrived in French Guiana in the first half of August. Fueling operations of all the spacecraft started on Aug. 19, and when this process had concluded, the next step was to integrate the satellites with the payload adapter, which took place on Aug. 25–26. Next, the PerúSAT-1 spacecraft was lowered onto the Vega Secondary Payload Adaptor (VESPA) prior to encapsulation. SkySat satellites were integrated on VESPA, and on Aug. 31, the stack was encapsulated in a payload fairing to create the upper composite.
One day before the encapsulation, final inspection of the launch vehicle was conducted. The upper composite was installed onto the launcher on Sept. 5, which cleared the way for fueling of the upper stage and the Roll and Attitude Control Subsystem (RACS). On Sept. 12, the final pressurization and rehearsal of the upper stage took place, and one day later, the arming of the launch vehicle and the payload fairing was carried out.
Launch readiness review is planned to be conducted on Sept. 14. On the same day, final preparations and inspections of the launcher and the fairing will be performed. Countdown operations are scheduled to start nine hours before liftoff.
During the countdown procedure, various systems of the launch vehicle will be turned on, including an onboard computer. Safety devices are planned to be removed around four hours and 40 minutes prior to liftoff. About three hours before the scheduled ignition of the rocket’s engines, a mobile gantry will be withdrawn, signaling the start of final pre-launch checks.
Afterward, the teams will activate transponders, receptors, and the telemetry transmitter. The synchronized sequence that will lead Vega to its flight will commence four minutes ahead of the launch.
Built by Airbus Defence and Space, PerúSAT-1 is Peru’s first Earth observation satellite. Weighing about 948 pounds (430 kilograms), it has dimensions of 3.3 by 3.3 by 5.6 feet (1.0 m × 1.0 m × 1.7 m). The spacecraft is based on Airbus’ AstroBus-S platform and is fitted with two solar cells.
PerúSAT-1 will be operated by Peruvian Armed Forces for up to 10 years. The satellite will offer its Earth-observing services from a Sun-synchronous orbit (SSO) at an altitude of 432 miles (695 kilometers). It will provide high-resolution pictures of Earth (2.3 feet / 70 cm per pixel) thanks to its New Astrosat Observation Modular Instrument (NAOMI) and its latest-generation silicon-carbide optical sensor.
PerúSAT-1 is expected to be a primary source of remote sensing data for Peru. The imagery from this satellite will be used both for civil and military purposes, with application areas ranging from homeland security and border monitoring, coastal surveillance, and the fight against illegal trafficking, to mining, geology, hydrology, disaster management, and environmental protection.
“With PerúSAT-1, we will be able to properly manage our resources, to better plan the growth of our cities, and we will also be able to provide accurate information for proper intervention against the consequences of climate change – to name but a few examples,” said Ronal Barrrientos, Product Assurance Manager at the Peruvian Space Agency (CONIDA).
The four SkySat micro-satellites, designated SkySat-4, -5, -6, and -7, were manufactured by Space Systems/Loral (SSL). Each spacecraft weighs 242 pounds (110 kilograms) and has dimensions of 2 by 2 by 3.1 feet (0.6 m × 0.6 m × 0.95 m). The quartet will be inserted into SSO at an altitude of 310 miles (500 kilometers).
The SkySat satellites are operated by Terra Bella – a Google subsidiary. The company uses these satellites to acquire high-resolution Earth observation satellite imagery for commercial purposes, high-definition video, and analytics services. The four new spacecraft will expand Terra Bella’s existing network of three satellites currently in orbit that were launched in November 2013, July 2014, and June 2016.
“As we continue to grow our constellation, we will be able to construct a living, breathing snapshot of any location in the world within hours, and tackle more problems around the globe,” Terra Bella wrote on its website.
The SkySat spacecraft are equipped with a Ritchey-Chretien Cassegrain telescope with a focal length of 3.6 m, and a focal plane consisting of three 5.5 Mpx CMOS imaging detectors. According to Terra Bella, SkySats employ a two-dimensional sensor array with a proprietary image filter to obtain high-quality images by taking multiple frames per second and stitching them on the ground, which also allows it to capture high-resolution commercial video of Earth.
The Vega rocket that will be employed for Thursday’s flight is a single-body launcher with three solid-propellant stages and a liquid-propellant upper module for attitude and orbit control as well as satellite release.
With a height of 98 feet (30 meters) and a diameter of 9.8 feet (3 meters), the launcher is described as being capable of placing satellites with a mass of 660–3,300 pounds (300–1,500 kilograms) into polar or low-Earth orbits that are used for many scientific and Earth observation missions. The first flight of this booster took place in February 2012.
The rocket’s first stage is a one-piece solid-fuel rocket engine named P80. This stage is 38 feet (11.7 meters) tall with a diameter of 9.8 feet (3 meters). After liftoff, P80 burns for approximately one minute and 50 seconds.
Zefiro 23 is Vega’s second stage with a height of 27.5 feet (8.39 meters) and a diameter of 6.2 feet (1.9 meters). The engine of this stage burns for one minute and 17 seconds.
The rocket’s third stage – Zefiro 9 – is 13.5 feet (4.12 meters) in length and 6.2 feet (1.9 meters) in diameter. This stage powers the launch vehicle for two minutes during the flight.
Vega’s upper stage, named Attitude Vernier Upper Module (AVUM), has dimensions of 5.6 by 6.2 feet (1.7 m × 1.9 m). It consists of two modules: APM (AVUM Propulsion Module) and AAM (AVUM Avionics Module). The first one uses an RD-843 rocket engine to boost the payload into a targeted orbit, while the second contains the main components of the avionics subsystem of the vehicle. The burn time of this stage is 11 minutes and seven seconds.
Thursday’s launch will be Arianespace’s seventh mission of the year as well as Vega’s seventh flight overall. The company’s next orbital mission is currently scheduled for Oct. 4 when an Ariane 5 launcher is slated to orbit the Sky Muster 2 (NBN-Co 1B) and the GSAT-18 communications satellites.
Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.