* Astronomy

Blobrana · L

RE: BLAST balloon

Blobrana · L

Title: BLAST Autonomous Daytime Star Cameras
Authors: Marie Rex (1), Edward Chapin (2), Mark J. Devlin (1), Joshua Gundersen (3), Jeff Klein (1), Enzo Pascale (4), Donald Wiebe (4) ((1) University of Pennsylvania,(2) University of British Columbia,(3) University of Miami,(4) University of Toronto)

Researchers have developed two redundant daytime star cameras to provide the fine pointing solution for the balloon-borne submillimeter telescope, BLAST.
The cameras are capable of providing a reconstructed pointing solution with an absolute accuracy less than 5 arcseconds. They are sensitive to stars down to magnitudes ~ 9 in daytime float conditions. Each camera combines a 1 megapixel CCD with a 200 mm f/2 lens to image a 2 degree x 2.5 degree field of the sky. The instruments are autonomous. An internal computer controls the temperature, adjusts the focus, and determines a real-time pointing solution at 1 Hz.
The mechanical details and flight performance of these instruments are presented.

A picture of the BLAST payload.
The gondola consists of an outer frame which is pointed in azimuth using a flywheel/pivot system, and an inner frame which moves independently in elevation. The inner frame houses the telescope, detectors, and the two star cameras, and is pointed relative to the outer frame using servo motors mounted inside the elevation bearing.

Read more (PDF)

Blobrana · L

BLAST finally landed at 06:15 UT on 16 June on Victoria Island in Canada.
(71degrees 09,6 minutes North, 110 degrees 49,2 minutes West.)

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The recovery operation should be completed within the next week.
The payload will be partially disassembled at the impact site and transported back to the Cambridge Bay by helicopter and aircraft. Then it will be returned to the scientists at the University of Pennsylvania.
Scientists on the scene report that the experiment sustained only very minor damage during the landing and that it is in excellent condition. They hope to refurbish the instrument and fly it again within a year or two.
Most of the data was stored on board the instrument during the flight.
The data vaults have been removed and the scientists will soon begin analyzing the data.
Preliminary results are expected within a few months but it will take a few years to analyze all the data.

Source

Blobrana · L

A telescope loaded with information that will help scientists around the world understand how stars are formed and how galaxies evolve landed in northern Canada early yesterday.

The telescope, called BLAST (Balloon-borne Large Aperture Sub-millimetre Telescope), was housed in a football stadium-sized balloon and touched down on Victoria Island, in the Arctic Archipelago, after a four-day trek that began in Kiruna, Sweden.

Danny Ball, of the National Scientific Balloon Facility, which was contracted by NASA, said his team remotely brought down the balloon before it went too far north over the Arctic Ocean.

Ball, who has participated in hundreds of smaller astrological missions involving balloons, said BLAST appeared to be highly-successful and will provide scientists with reams of data to study the universe.

Sweden was chosen as a launch site to ensure an extremely long flight west, he said from Texas.

Denis Laurin, a scientist with the Canadian Space Agency, which partly funded the international collaboration, said the telescope was the largest that has ever flown on a balloon to gather data from stars and far-flung galaxies.

"It used very sophisticated detectors," Laurin said.

The telescope recorded data far above the atmosphere `at about 40,000 metres` about four times higher than commercial airplanes fly.

At that point, special detectors on the telescope gathered information from the far infrared light that`s not visible to the human eye, Laurin said.

"At that altitude, you`re pretty much 95 percent above all the atmosphere and so 95 percent of the air is below you and there`s only five percent left," he noted.

By looking at signals from distant galaxies, scientists can determine how they and the stars in them are forming and how the universe evolved.

"We`re above the atmosphere and we`re doing science that we would typically do from space and that`s why this falls into the Canadian Space Agency program," Laurin said of the mission.

The 20-metre BLAST telescope is similar to technology that will be developed for a telescope called Herschel, to be launched by the European Space Agency in 2007 with two Canadian instruments on board, he added.

Along with the University of Toronto and the University of British Columbia, facilities in the United States, Britain, Mexico, and Sweden participated in the BLAST mission.

Canada`s contribution included the gondola, which held the telescope and its instruments, and the pointing control system to observe certain stars or galaxies.

It will take years for the data to be analyzed by various facilities around the world, Laurin said.

"Essentially it`s an understanding of our destiny" he remarked.

source

-- Edited by Blobrana at 00:34, 2005-06-18

Blobrana · L

UPDATE:
MISSION OVER (nearly)

Blobrana · L

Today, at 03.10, local time, a giant balloon was launched from Esrange, the Aerospace Operation Facility of the Swedish Space Corporation.
The balloon is carrying BLAST, a large sub-millimetre telescope for studies of star formation.

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Real time GPD data and payload track

Never before has such a huge balloon been launched from Europe with such a heavy instrument. High altitude winds will carry the telescope from Sweden to a landing near the border between Canada and Alaska.

For several years scientists from different university and institutes from the USA, Canada, United Kingdom and Mexico have been preparing this large telescope. The campaign is sponsored by NASA. The operation will be supported by The National Scientific Balloon Facility (NSBF) in cooperation with the Swedish Space Corporation (SSC) balloon team at Esrange.

"BLAST will address some of the most important cosmological and galactic questions regarding the formation and evolution of stars, galaxies and clusters. It makes use of bolometric arrays to achieve highly sensitivity images at three sub-millimetre wavelengths, while at the same time testing technology used in the future ESA sub-millimetre space telescope Herschel to be launched in 2007" - Prof. Mark Devlin, University of Pennsylvania, Principal Investigator of BLAST.

"A launch of a balloon of this size is extremely complicated. We have been working hard, investing both time and money to reach the point where we are today so this campaign is a milestone for us. We are also deeply impressed by our American colleagues from NASA and its National Scientific Balloon Facility " - Dr. Olle Norberg, Head of Esrange.

"We are very grateful for the wonderful facilities at Esrange and all the hard work our Swedish colleagues have put into this project" - Danny RJ Ball, NSBF Site Manager.

NASA has plans to return to Esrange next year to launch 2-3 experiments under development.
There are many advantages in launching scientific balloons from Esrange. First, the geographic location allows measurements in total sun light due to the midnight sun. If total darkness is required, instruments are launched during the winter time during polar night. Esrange has a large launch pad the size of 40 soccer fields and several well equipped buildings for preparation of the experiments. Esrange provides scientists with long-duration flights and safe landings on land, due to well known winds in the stratosphere that allows for safe flight trajectories and a landing site in North America.
Performing scientific measurements with balloon-borne instruments has some advantages when compared to satellites. The development time is considerably shorter for a balloon borne experiment and the costs are much lower. This means that balloon projects are also very suitable for Ph.D. students and an important tool to train future scientists.

Facts
• BLAST: Balloon-borne Large Aperture Sub-millimetre Telescope
• Size of the balloon: 140 meter in diameter and 120 m high
• Balloon volume: 1,2 million m3
• Gas: 5000 m3 helium delivered by AGA
• Flight time: 5-7 days
• Altitude: 38- 40 km
• Size of the telescope: Mirror 2 m diameter
• Weight of the telescope: 1,5 ton (2,7 ton with all technical equipment)
• Size of the launch pad: 250 000 m2
Read more about the science: BLAST http://chile1.physics.upenn.edu/blastpublic