High winds put paid to an attempt last night to launch Arianespace’s second Vega lightweight booster from the Guiana Space Center in Kourou, French Guiana, to deploy three satellites into two different orbits. According to Arianespace, a new target date for the ambitious VV-02 mission will await more favorable weather conditions, and it is understood that a delay of at least 48 hours is likely. The 98-foot-tall, four-stage vehicle represents the smallest member of the European launch organization’s fleet and will carry satellites for the European Space Agency (ESA), the Vietnamese government, and students from Estonia.
Originally scheduled to launch at 11:06:31 p.m. local Kourou time on Friday (2:06:31 a.m. UTC on Saturday), with a “window” lasting barely one second, the attempt proceeded smoothly during the final hours of its countdown. The gantry was retracted to expose Vega and the rocket and its payloads were declared ready to go, but with around 40 minutes remaining the launch was scrubbed when atmospheric balloon data indicated “very high winds” in the region. “The postponement was based on strict safety conditions applied for Arianespace launch operations,” noted the organization in its post-scrub press release. “The Vega vehicle and its three spacecraft passengers … remain in a safe, standby mode at the Spaceport’s SLV launch site.”
This mission will follow hard on the heels of the maiden VV-01 launch in February 2012, which put Vega through its paces as the lightest booster in Arianespace’s fleet. However, whereas VV-01 was an inaugural demonstration of the vehicle, the second flight is far more ambitious, with plans to deploy its three satellite payloads at two different orbital altitudes. It marks the first in a series of five Vega Research and Technology Accompaniment (VERTA) missions to demonstrate its flexibility and ability to transport multiple spacecraft into different orbits. In future developments, Arianespace hopes to utilize Vega in 2015 to launch the LISA Pathfinder—a technology demonstrator for the joint NASA/ESA Laser Interferometer Space Antenna—into a “halo orbit” around the L1 Earth-Sun Lagrange Point.
Designated “VV-02,” the name of the second mission pays tribute to the first letter in the French word for “flight” (“vol”), together with the first letter of the Vega itself and, lastly, the numerical sequence of the mission itself. In February 2012, the first Vega mission lofted nine discrete payloads—including Italy’s 850-pound Laser Relativity Satellite (LARES)—into orbit, marking a triumphant success after 14 years in development. Although Vega includes co-operation between France, Belgium, The Netherlands, Spain, Switzerland, and Sweden, it is Italy which has driven the program, with a 65-percent contribution. In the wake of its VV-01 mission, Vega joined the medium-lift Soyuz and the heavy-lift Ariane 5 as the third member of Arianespace’s versatile fleet of boosters.
“Vega” is an Italian-language acronym for Vettore Europeo di Generazione Avanzata (Advanced Generation European Carrier Rocket). It has no strap-on rockets, but instead consists of three solid-fueled stages, all built by Avco, the Turin-based aerospace and defense contractor, together with an Attitude Vernier Upper Module (AVUM) fourth stage. The latter employs a bi-propellant liquid-fuel mix of unsymmetrical dimethyl hydrazine and nitrogen tetroxide and is fed by a Russian-built RD-869 engine. The VV-02 flight will begin with the ignition of the P-80 first stage, which produces a maximum thrust of 683,400 pounds and will burn for the first 109.8 seconds of the flight. The second stage, known as the Zefiro-23, capable of 269,700 pounds of thrust, will then fire for 77.7 seconds, and finally the third stage, the Zefiro-9, with 47,880 pounds of thrust, will ignite for 117 seconds.
After the burnout and separation of the Zefiro-9, the turn will come of the AVUM, which will perform no fewer than four firings to establish its three satellite payloads in their required orbits. During this period, it will deploy Vietnam’s VNREDSat-1 and Estonia’s ESTCube-1 at an altitude of 420 miles and the European Space Agency’s Proba-V at 510 miles. The Estonian satellite is a small CubeSat and is expected to survive for about 12 months, but VNREDSat-1 and Proba-V should endure for up to five years. After the separation of the satellites, the AVUM will perform a final “deorbit” burn to eliminate itself as a space debris threat.
From liftoff until final payload separation, the VV-02 mission is scheduled to last two hours and 48 seconds. Originally due to fly in mid-April, it was postponed until 2 May and subsequently moved 24 hours further to the right. According to Arianespace, the slight final delay was made in order “to carry out additional checks on the mobile gantry system used on the Vega launch complex.” Aside from the high winds on Friday night, other rocket and spacecraft systems appeared normal.
All three payloads arrived in French Guiana in March, with Proba-V and VNREDSat-1 touching down at Félix Eboué Airport, near the capital city of Cayenne, aboard a charted Boeing 747 cargo aircraft. By 17 April, the three satellites—including the tiny ESTCube-1—had been encapsulated into the Vega payload stack. At the time of writing this article, processing at the Guiana Space Center continues to proceed smoothly, and Arianespace reported on Wednesday that final preparations to fuel the AVUM upper stage had been successfully concluded.
The Proba-V is by far the largest payload aboard VV-02. Weighing 308 pounds, it will be placed into a Sun-synchronous orbit of 510 miles, inclined 98.1 degrees to the equator, and will support new technology development for Earth-resources detectors. Specifically, it is equipped with a reduced-mass version of the Vegetation instrument, currently used by the French Spot-4 and Spot-5 satellites, and will provide daily overviews of global vegetation growth patterns. Initiated by the Belgian Science Policy Office, the Proba-V spacecraft was built by ESA and its scientific focuses include land use, vegetation classification, crop monitoring, famine prediction, food security, disaster planning, and biosphere studies. Since the Spot-5 mission is due to end in mid-2014, Proba-V offers vital continuity, ahead of the first launch of the next-generation Sentinel Earth-observation program. In December 2011, Arianespace signed contracts to launch the Sentinel-2B and 3B satellites, which are required to be in orbit in the 2015-16 timeframe.
Sitting “beneath” Proba-V, in the lower position of the VESTA dual-satellite adaptor, will be Vietnam’s VNREDSat-1. This 165-pound payload is part of Vietnam’s effort to develop an orbiting infrastructure to study climate change, predict natural disasters, and optimize the management of natural resources. It was built by Astrium on behalf of the Vietnam Academy of Science and Technology and will be deployed into an orbit of 420 miles. The final payload aboard VV-02 is Estonia’s 2.9-pound ESTCube-1, which has been assembled by students at the National University of Tartu, in conjunction with the Estonian Space Office, the Finnish Meteorological Institute, and the German Space Center (DLR). One of the primary functions of the tiny CubeSat will be the extension of an “ultra-thin and hopefully snap-proof” conducting tether to test electrical solar wind sail technologies.
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