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#26 2006-03-29 06:01:49

EuroLauncher
Member
From: Europe
Registered: 2005-10-19
Posts: 299

Re: Dawn - Vesta & Ceres orbiter

Wow, That's unexpectedly good news, yay for Griffin, it looks like he does have a knack to make hard decisions (delaying or scrapping missions) and an even better knack of reconsidering decisions already made...

What a relief to have a guy like him at the helm!

great news for Dawn !

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#27 2006-04-05 20:59:56

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 349

Re: Dawn - Vesta & Ceres orbiter

Powered by a xenon ion engine, Dawn would be the first spacecraft to circle Ceres and Vesta. It will spend several months orbiting each asteroid, photographing the surface and studying the interior composition, density and magnetism.
Ceres and Vesta are believed to have formed in different parts of the solar system about 4.5 billion years ago. Studying them could provide clues to how the sun and planets formed.
story
Dawn's cancellation came at a precarious time at NASA, which had been forced to cut or delay several science projects to help pay for the development of new manned vehicles to return to the moon next decade.
Jet Propulsion Laboratory director Charles Elachi appealed the cancellation, saying the technical problems were either fixed or would be corrected in time for a liftoff next year.

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#28 2006-06-18 23:10:22

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Detailed article about the development problems of this amazing mission that uses three ion engines.

With the flight tank already built, it is impossible to reengineer or repair it based on the test findings. The only realistic path Dawn managers can take is to reduce the pressure inside the flight tank. This will be done by reducing the amount of xenon Dawn will carry from the original plan of 450 kg to 425 kg and reducing the operating temperatures to 30 C from 40 C.


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#29 2006-10-30 21:08:00

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Last chance to have your personal bit pattern copied onto the Dawn spacecraft! 

Just enter your name here, nothing else

Dawn is planned to perform a gravity assist at Mars in March 2009

Bon Voyage!


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#30 2007-01-20 16:56:40

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

05.jpg01.jpg 03.jpg
02.jpg04.jpg06.jpg
Attachment and test deployment of one of the two solar array wings on 11 Oct 2006 - she'll fly on 20 Jun 2007


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#31 2007-03-05 11:08:58

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Dawn Journal 19 Feb 2007, by Marc Rayman, project system engineer

The Dawn spacecraft has just completed the final and most challenging of the environmental tests needed to prepare for its launch and travels through space. During the past month, it has endured the extreme heat and cold of spaceflight in a large vacuum chamber at the Naval Research Laboratory (NRL) in Washington, DC.


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#32 2007-04-05 00:17:36

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

The Dawn Mission to the Asteroid Belt - webcast lecture now archived (77 mins)

Project Systems Engineer Marc Rayman gives a great introductory lecture describing the Dawn mission and the triple Ion drive spacecraft.


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#33 2007-04-06 00:42:55

RedStreak
Member
From: Illinois
Registered: 2006-05-12
Posts: 541

Re: Dawn - Vesta & Ceres orbiter

...now if I can just download the damn Real Player to watch it.  :evil:

Hopefully June will come soon for its launch.  smile

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#34 2007-04-06 01:24:57

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

...now if I can just download the damn Real Player to watch it.

Real Alternative works well on windows systems and it's crapware free.


Let's go to Mars and far beyond -  triple NASA's budget !   #space channel !!    - videos !!!

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#35 2007-04-11 06:41:18

RedStreak
Member
From: Illinois
Registered: 2006-05-12
Posts: 541

Re: Dawn - Vesta & Ceres orbiter

...now if I can just download the damn Real Player to watch it.

Real Alternative works well on windows systems and it's crapware free.

Yay crapware free!  It works finally.

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#36 2007-04-11 07:47:09

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Dawn Arrives in Florida - A Little After Dawn

NEWS RELEASE: 2007-038                                                                              April 10, 2007

The Dawn spacecraft arrived at Astrotech Space Operations in Titusville, Fla., at 9 a.m. EDT today. Dawn, NASA’s mission into the heart of the asteroid belt, is at the facility for final processing and launch operations. Dawn’s launch period opens June 30.

"Dawn only has two more trips to make," said Dawn project manager Keyur Patel of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. "One will be in mid-June when it makes the 15-mile journey from the processing facility to the launch pad. The second will be when Dawn rises to begin its eight-year, 3.2-billion-mile odyssey into the heart of the asteroid belt."

The Dawn spacecraft will employ ion propulsion to explore two of the asteroid belt's most intriguing and dissimilar occupants: asteroid Vesta and the dwarf planet Ceres.

Now that Dawn has arrived at Astrotech near NASA’s Kennedy Space Center, final prelaunch processing will begin. Technicians will install the spacecraft’s batteries, check out the control thrusters and test the spacecraft’s instruments. In late April, Dawn’s large solar arrays will be attached and then deployed for testing. In early May, a compatibility test will be performed with the Deep Space Network used for tracking and communications. Dawn will then be loaded with fuel to be used for spacecraft control during the mission. Finally, in mid-May, the spacecraft will undergo spin-balance testing. Dawn will then be mated to the upper stage booster and installed into a spacecraft transportation canister for the trip to Cape Canaveral Air Force Station. This is currently scheduled for June 19, when it will be mated to the Delta II rocket at Pad 17-B.

The rocket that will launch Dawn is a Delta II 7925-H manufactured by the United Launch Alliance; it is a heavier-lift model of the standard Delta II that uses larger solid rocket boosters. The first stage is scheduled to be erected on Pad 17-B in late May. Then the nine strap-on solid rocket boosters will be raised and attached. The second stage, which burns hypergolic propellants, will be hoisted atop the first stage in the first week of June. The fairing which surrounds the spacecraft will then be hoisted into the clean room of the mobile service tower.

Next, engineers will perform several tests of the Delta II. In mid-June, as a leak check, the first stage will be loaded with liquid oxygen during a simulated countdown. The next day, a simulated flight test will be performed, simulating the vehicle’s post-liftoff flight events without fuel aboard. The electrical and mechanical systems of the entire Delta II will be exercised during this test. Once the Dawn payload is atop the launch vehicle, a final major test will be conducted: an integrated test of the Delta II and Dawn working together. This will be a combined minus and plus count, simulating all events as they will occur on launch day, but without propellants aboard the vehicle.


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#37 2007-05-14 01:25:15

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

07pd0864-m.jpg
Inside clean room C of Astrotech's Payload Processing Facility at KSC - imaged 11 Apr 2007

Comprehensive Performance Tests Completed

April 30 - May 4
The spacecraft successfully completed two weeks of comprehensive performance tests. In these tests, each engineering subsystem and each instrument is operated extensively to verify it continues to function as required. The first run of the same tests was conducted in 2006, so engineers can verify that now that the spacecraft is in final preparation for launch, no unexpected changes have occurred as a result of the environmental tests or the shipment of the spacecraft.

Launch in 48 days!


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#38 2007-06-06 15:51:09

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Launch delayed to 7 July - 6 Jun 2007

Expendable Launch Vehicle Status Report

Mission: Dawn
Location: Astrotech Space Operations Facility
Launch Pad: 17-B
Launch Vehicle: Delta II 7925-H
Launch Date: July 7, 2007
Launch Time: 4:09:31 - 4:36:22 p.m. EDT

At Pad 17-B, the Delta II first stage was hoisted into the launcher on May 28 after a postponement due to high wind at the launch pad. Technicians then began working to erect the nine solid rocket boosters. A mechanical problem with the crane used to hoist and mate the first set of three boosters stalled further launch vehicle build-up. As a result of the crane problem at the pad, the launch of Dawn has been retargeted for July 7. Repairs to the crane are now complete. The operations to attach the solid rocket boosters resumed today. The second stage is planned to be hoisted atop the first stage on June 20.

Due to the change in the launch date, the planned loading of xenon for the ion propulsion system was rescheduled. The operation began Tuesday night and is under way today. Hydrazine, used for spacecraft control and maneuvering, is scheduled to be loaded on June 10. The spacecraft will be transported to Pad 17-B for mating to the Delta II on June 26.


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#39 2007-06-14 13:44:11

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

07pd1388-m.jpg
Loading xenon gas for the ion propulsion system - imaged 7 Jun 2007


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#40 2007-06-25 08:31:20

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

07pd1613-m.jpg
Spacecraft secured onto the upper stage booster - imaged 21 Jun 2007


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#41 2007-06-27 05:09:04

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Article with quotes from Christopher Russell, Principle Investigator - 26 Jun 2007

UCLA Professor Christopher Russell Leads NASA’s Dawn Mission, a Journey Through Space and Time, Scheduled for July 7 Launch

Christopher T. Russell, UCLA professor of geophysics and space physics, has spent 15 years working on NASA's Dawn mission to the doughnut-shaped asteroid belt between Mars and Jupiter. As the scheduled July 7 launch from Cape Canaveral nears, Russell is ready, and so is Dawn.

"The spacecraft will spend much less time in space than we put in preparing for the mission," said Russell, the mission's principal investigator. "I want to get this spacecraft up in space, where it belongs. I'm really confident about the spacecraft. We've been testing and retesting."

Dawn will conduct a detailed study of the structure and composition of two of the first bodies formed in our solar system: the "dwarf planet" Ceres and the massive asteroid Vesta. The mission's goals include determining the shape, size, composition, internal structure, and the tectonic and thermal evolution of Vesta and Ceres. Dawn, which will be the first spacecraft to orbit two planetary bodies on the same mission, is expected to reveal the conditions under which these objects formed. Comparing their different evolutionary paths will provide evidence about the role of size and water in planetary evolution.

Dawn is scheduled to fly past Mars by April 2009, and after more than four years of travel, the spacecraft will rendezvous with Vesta in 2011. The spacecraft will orbit Vesta for approximately nine months, studying its structure and composition. In 2012, Dawn will leave for a three-year cruise to Ceres. Dawn will rendezvous with Ceres and begin orbit in 2015, conducting studies and observations for at least five months.

"I think of Dawn as two journeys," said Russell, who proposed the mission to NASA. "One is a journey into space. This is analogous to what ancient explorers did, who knew there was unexplored territory and wanted to discover what was there. We're going to explore a region for the first time to find out what the conditions are today.

"Dawn is also a journey back in time. Ceres and Vesta have been altered much less than other bodies. The Earth is changing all the time; the Earth hides its history, but we believe that Ceres and Vesta, formed more than 4.6 billion years ago, have preserved their early record. They're revealing information that was frozen into their ancient surfaces. By looking at the surface and how it was modified by the bombardment of meteoroids, we will get an idea of what the early conditions of Ceres and Vesta were and how they changed. So Dawn is a history trip too. We're going back in time to the early solar system."

Ceres could harbor life.

"Evidence indicates it has substantial water or ice beneath its rocky crust," Russell said. "Our instruments on board will be able to determine whether there is water."

Dawn's instruments include a gamma ray and neutron spectrometer that can detect the hydrogen from water.

Evidence of whether water still exists on Ceres could come from frost or vapor on the surface, and possibly liquid water under the surface. The water kept Ceres cool throughout its evolution. In contrast, Vesta was hot, melted internally and became volcanic early in its development. Ceres remains closer to its primordial state, while Vesta evolved further over the first few millions of years of its existence, Russell said.

Ceres, named for the Roman goddess of agriculture, revolves around the sun every 4.6 terrestrial years and has an average diameter of approximately 600 miles. A roughly round object, Ceres orbits the sun in the asteroid belt between Mars and Jupiter, approximately 258 million miles from Earth. Ceres is much larger than Vesta — more than two times further across, with a volume eight or nine times greater — but is less dense, as the material in it is lighter.

Vesta, the brightest asteroid, is named for the ancient Roman goddess of the hearth. Approximately 220 million miles from Earth, it appears to be essentially solid rock, with a density similar to Mars. It orbits the sun every 3.6 terrestrial years, has an oval, pumpkin-like shape, and has an average diameter of approximately 320 miles. Vesta's basaltic dust layer reflects its crustal composition, and its dry surface includes a huge crater near its southern pole.

Studies of meteorites believed to be from Vesta that were found on Earth suggest that this body formed from galactic dust during the solar system's first 3 to 10 million years. Although no meteorites from Ceres have been found, it is believed this body also formed during the first 10 million years of the solar system's existence, Russell said.

Dawn is expected to bring high-resolution images of previously unseen worlds to the public, including, perhaps, mountains, canyons, craters and ancient lava flows. In addition to the images, Dawn will generate data that will help scientists identify geologic minerals and will take measurements of gamma rays and neutrons. The gamma-ray measurements will reveal which elements are in the minerals. The data are expected to arrive a scant 30 minutes after the spacecraft obtains them.

Dawn, which will orbit as close as 125 miles from Ceres and Vesta, is the first purely scientific mission designed to be powered by an advanced NASA technology known as ion propulsion. Unlike chemical rocket engines, ion engines accelerate their fuel nearly continuously, giving each ion a tremendous burst of speed. The fuel used by an ion engine is xenon, a gas also used in photo-flash units, which is more than four times heavier than air. This results in a xenon atom with a positive charge — a xenon ion. The xenon ions shoot out the back of the engine at a speed of 78,000 miles per hour.

At full throttle, the ion engine consumes 2,300 watts of electrical power and produces 1/50th of a pound of thrust — about the same pressure as a sheet of paper resting on the palm of a hand, and far less thrust than is produced by even small chemical rockets. This engine, for a given amount of fuel, can gradually increase a spacecraft's velocity 10 times more than can a conventional rocket powered by liquid or solid fuel.

UCLA is in charge of Dawn's science and public outreach. Russell leads the science team, brings together the mission's partners, manages the budget and participates in all major decisions. Russell and his colleagues will make science decisions and develop the operations plans through the science center at UCLA's Institute of Geophysics and Planetary Physics. His science team has the lead role for analyzing and interpreting the data from Dawn. UCLA graduate students and postdoctoral scholars will work on the mission, including helping to analyze the data from Dawn.


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#42 2007-06-30 05:07:12

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

07pd1678-m.jpg
Inside the mobile service tower, Pad 17-B at Cape Canaveral.
Mated onto the Delta II launch vehicle - 27 Jun 2007


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#43 2007-07-02 04:21:20

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

NASA Dawn Mission Video (Video Google 13:19 mins)

Leonard Nimoy narrates while mission scientists and engineers explain the science and technological challenges of visiting the Asteroid Belt.


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#44 2007-07-03 05:02:39

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

07pd1718-m.jpg
First half of the fairing being moved into position - imaged 1 Jul 2007


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#45 2007-07-04 03:09:14

cIclops
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Re: Dawn - Vesta & Ceres orbiter

flight readiness review complete - 3 Jul 2007

STATUS REPORT: ELV-070307

EXPENDABLE LAUNCH VEHICLE STATUS REPORT

Mission: Dawn
Launch Pad: 17-B
Launch Vehicle: Delta II 7925-H
Launch Date: July 7, 2007
Launch Time: 4:09:31 - 4:36:22 p.m. EDT

The flight readiness review was completed on Tuesday. All technical
issues were cleared.

Mission managers will hold a teleconference on Wednesday to discuss
the availability of telemetry assets. If it is determined there are
sufficient aircraft and ship assets available, the team will proceed
with propellant loading on Thursday.


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#46 2007-07-07 03:36:07

cIclops
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Registered: 2005-06-16
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Re: Dawn - Vesta & Ceres orbiter

Mission briefing - (Video 40:37 mins) - 6 Jul 2007

Detailed introduction to the mission and science.

Launch has been postponed to NET 15 Jul 2007


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#47 2007-07-08 03:02:15

cIclops
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Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Rescheduled for September Launch - 7 Jul 2007

WASHINGTON - The launch of NASA's Dawn spacecraft, a mission that will explore the two largest objects in the asteroid belt in an effort to answer questions about the formation of our solar system, has been rescheduled to September.

The decision was made today to move the launch to September after careful review by NASA's Science Mission Directorate officials, working with Dawn mission managers, the Dawn principal investigator, and with the concurrence of the NASA Administrator.

Primary reasons for the move were a combination of highly limited launch opportunities for Dawn in July and the potential impact to launch preparations for the upcoming Phoenix Mars Lander mission, set for early August. A September launch for Dawn maintains all of the science mission goals a July launch would have provided.


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#48 2007-07-12 20:29:46

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 14,575

Re: Dawn - Vesta & Ceres orbiter

Not exagerating and I thought going to mars was slow...
The Slow-Motion Mission

Ion propulsion sidesteps that whole mess. Rather than rely on common combustible fuel, it uses xenon gas, a comparatively light 937 lbs. (425 kg) of it loaded into a compact 72-gal. (273 L) tank.

A jolt of electricity energizes the gas, causing xenon ions to shoot out the back of the ship at 77,000 m.p.h. (124,000 km/h). A stream of charged atoms has somewhat less oomph than a burst of fire--less force than the weight of a single piece of paper, in fact--but over time it adds up. "It's acceleration with patience," says Rayman. "

In the four days it takes to increase speed by 60 m.p.h., we'll use only 2 lbs. of propellant. If we keep thrusting, however, we can achieve extremely high speed." Indeed they can.

By the time Dawn completes its four-year journey to the neighborhood of Vesta, a trip made longer by the slow acceleration, it will have sped up by 24,500 m.p.h. (39,400 km/h) and will be tearing along as fast as any interplanetary ship has ever propelled itself.

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#49 2007-07-13 11:27:32

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Yes that's the big advantage of ion drive, it can launch two months later and it barely changes the mission timeline smile


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#50 2007-09-08 00:33:28

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Dawn - Vesta & Ceres orbiter

Mission status updates

Preparations for Mission Operations Continue
September 3 - 7
The operations team continued development of command sequences to be used during the first phase of the mission, known as initial checkout. These commands will guide the spacecraft through activities to provide data for engineers to use in evaluating the health and performance of all subsystems. Meanwhile, plans were completed for transporting the spacecraft back to the launch pad next week.

Operations Team Simulates Launch and Operations
August 27 - 31
The operations team conducted simulations at JPL this week covering the last 16 hours of countdown, launch, and early operations. The simulation supervisor intentionally created some problems, all of which the team handled successfully.

Launch Period Established
August 20 - 24
This week, NASA chose September 26 to October 15 as Dawn's launch period. Computer files that will be used during the final countdown were tested on the spacecraft, demonstrating that they work correctly.


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