Arianespace is gearing up for the seventh launch of Vega rocket in history, that will 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 inserting the satellites into an elliptic low-Earth orbit (LEO).
The mission campaign started in June with the assembly of Vega launcher. The teams were busy throughout the month to integrate all the 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 concluded, the next step was to integrate the satellites with the payload adapter what took place on Aug. 25-26. Next, the PerúSAT-1 spacecraft was encapsulated on the Vega Secondary Payload Adaptor (VESPA). 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, what 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, 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 campaign, 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 the 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 About three hours before the scheduled ignition of the rocket’s engines, a mobile gantry will be withdrawn, signaling the start of final pre-launch checks. Afterwards, the teams will activate transponders, receptors and the telemetry transmitter. The synchronized sequence that will lead Vega to its liftoff, will be commenced four minutes ahead of the launch.
Built by Airbus Defence and Space, PerúSAT-1 is Peru’s first Earth observation satellite. Weighing about 948 lbs. (430 kilograms), it has dimensions of 3.3 by 3.3 by 5.6 feet (1.0 x 1.0 x 1.7 meters). 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) 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).
Four SkySat micro-satellites, designated SkySat-4, 5, 6 and-7, were manufactured by Space Systems/Loral (SSL). Each spacecraft weighs 242 lbs. (110 kilograms) and has dimensions of 2 by 2 by 3.1 feet (0.6 by 0.6 by 0.95 meters). The quartet will be inserted into SSO at an altitude of 310 miles (500 kilometers).
SkySat satellites are operated by Terra Bella - a Google subsidiary. The company uses these satellites to acquire commercial high-resolution Earth observation satellite imagery, 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.
SkySat spacecraft are equipped in 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, what also allows to capture commercial high-resolution video of Earth.
Vega rocket that will be employed for Thursday’s liftoff is a single-body launcher with three solid-propellant stages and a liquid-propellant upper module for attitude and orbit control, and 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 660-3,300 lbs. (300–1500 kilograms) satellites into polar and low-Earth orbits used for many scientific and Earth observation missions. 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 diameters of 6.2 feet (1.9 meters). The engine of this stage burns for one minute and 17 seconds.
The rocket’s 13.5-feet (4.12-meters) third stage – Zefiro 9 – is also 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 x 6.2 feet (1.7 x 1.9 meters). It consists of two modules: APM (AVUM Propulsion Module) and AAM (AVUM Avionics Module). The first one uses a RD-843 rocket engine to boost the payload into targeted orbit, while the second contains the main components of the avionics sub-system 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 Sky Muster 2 (NBN-Co 1B) and GSAT-18 communications satellites.