Wednesday, June 10, 2015

Vega Rocket to Put Sentinel-2A Earth Observation Satellite into Orbit

Sentinel-2A Earth observation satellite being encapsulated on June 8, 2015. Credit: ESA

Vega launch vehicle is slated to lift off Europe’s Sentinel-2A Earth observation satellite at 9:51 p.m. EST on June 22 from ESA’s spaceport in Kourou, French Guiana. The preparations for the launch, previously scheduled for June 12, are on full swing as the spacecraft has been already fueled, mated with the launch adapter and encapsulated in the rocket fairing. The upcoming mission, designated Flight VV05, will be the fifth launch of the lightweight Vega rocket.

Built by Airbus Defence and Space, the 2,513 lbs. (1,140 kg) Sentinel-2A will deliver high-resolution and multispectral capabilities, providing a 180 miles-wide (290 km) coverage path and frequent revisits; and is to join the Sentinel-1A spacecraft put to orbit in April 2014. The satellite will be put into polar, Sun-synchronous orbit at an altitude of 477 miles (786 km).

The spacecraft is equipped with Multispectral imager (MSI) covering 13 spectral bands (443 nm–2190 nm). The instrument is the most advanced of its kind – in fact, it is the first optical Earth observation mission of its kind to include three bands in the ‘red edge’, which provide key information on vegetation state.

The MSI works passively, by collecting sunlight reflected from the Earth. New data is acquired at the instrument as the satellite moves along its orbital path. The incoming light beam is split at a filter and focused onto two separate focal plane assemblies within the instrument; one for Visible and Near-Infra-Red (VNIR) bands and one for Short Wave Infra-Red (SWIR) bands . The spectral separation of each band into individual wavelengths is accomplished by stripe filters mounted on top of the detectors.

Sentinel-2A is planned to be operational for more than seven years.

After the arrival at the launch site at the end of April, Sentinel-2A has been through a series of stringent tests to confirm there was no damage during the flight from Germany.

These tests have made sure that everything is in good working order so that this new satellite will deliver the images to monitor Earth’s vegetation and changing lands.

The fuelling of the satellite took place last week, after which it was joined to the Vega adapter.

The protective covers, were then removed before it was encapsulated in the rocket fairing. In the coming days, the satellite will be transferred the launch pad.

Vega 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 ft. (30 m) and diameter of 9.8 ft. (3 m), the launcher can place 660-3,300 lbs. (300–1500 kg) satellites, economically, into the polar and low-Earth orbits used for many scientific and Earth observation missions.

The Sentinel-2 mission is dedicated to Europe’s Copernicus environmental monitoring program, which is headed by the European Commission in partnership with ESA.

The new satellite will provide information for agriculture and forestry and for helping to manage food security. The images will be used to determine various plant features such as leaf chlorophyll and water content. 

As well as monitoring plant growth, the satellite will be used to map changes in land cover and to monitor the world’s forests. It will also provide information on pollution in lakes and coastal waters. Images of floods, volcanic eruptions and landslides will contribute to disaster mapping and helping humanitarian relief efforts.

Specifically, the mission will monitor variability in land surface conditions, and its wide swath width and high revisit time (10 days at the equator with one satellite, and 5 days with 2 satellites under cloud-free conditions which results in 2-3 days at mid-latitudes) will support monitoring of changes to vegetation within the growing season. The coverage limits are from between latitudes 56° south and 84° north.

Once the Sentinel data are acquired on-board, they are sent to ground and received at the X-band core stations located in Matera, Italy, Maspalomas, Spain and Svalbard, Norway.

Data can also be transmitted via laser-link to the European Data Relay System, which relays data via geostationary satellites to ground where they are received at the user Ka-band stations.

Each Sentinel satellite has a high level of autonomy, so that they can operate without any intervention from the ground for periods of up to 15 days.

Sentinel mission has been designed and built by a consortium of around 60 companies led by Airbus Defence and Space, and supported by the CNES French space agency to optimize image quality and by the DLR German Aerospace Centre to improve data recovery using optical communications.

June 22 launch will be Arianespace’s 5th mission this year, following two previous flights of Ariane 5 rocket, one Soyuz and one Vega.

Next Sentinel launch will take place in the second half of 2016.

1 comment:

  1. The protective covers, were then removed before it was encapsulated in the rocket fairing. In the coming days, the satellite will be transferred the launch pad. The Best Places to Buy a Pedometer Watch