ASTRA 1KR Launch Thursday 20th 20:27GMT

Zaphod

MONDAY, APRIL 17, 2006

A relay spacecraft for Europe's leading direct-to-home satellite TV service is packed aboard a commercial Lockheed Martin Atlas 5 rocket for the ride to its lofty perch 22,000 miles above the planet.

Blastoff time for the ASTRA 1KR satellite from Complex 41 at Cape Canaveral is Thursday at 4:27 p.m. EDT (2027 GMT), the opening of a two-hour, 49-minute window of opportunity to begin a 15-year mission in space. Weather forecasters expect favorable conditions.

The 191-foot tall rocket will be transferred from its assembly building to the launch pad aboard a 1.4-million pound mobile platform beginning around 10:50 a.m. Wednesday. The third-of-a-mile trip along rail tracks should take a half-hour.

The Atlas program is seeking its 79th consecutive successful launch extending back to 1993, an enviable record unmatched in today's rocket market. In fact, the modern Atlas 2, 3 and 5 rocket families have unblemished histories.

Thursday's flight will offer a highly unusual sight for spectators. Unlike earlier Atlas 5 missions that have used either multiple or simply no strap-on solid rocket motors, this launch features a single white booster mounted to the first stage.

Since the next-generation rocket's beginnings, Lockheed Martin designers have touted the vehicle's ability to fly with just the number of solid-fuel boosters necessary to loft the payload weight aboard. Each Atlas 5 rocket is tailored to its cargo with enough thrust to do the job, even if that means attaching an uneven number of solid motors.

The philosphy behind the design, officials say, makes each rocket only as complex as it needs to be and avoids flying a vehicle with too much excess power that would be wasted.

The ASTRA 1KR mission was booked on the Atlas 5-411 version, which has a four-meter nose cone covering the satellite, one solid rocket booster and a single-engine Centaur.

The rocket should launch safely with the unique one-booster configuration, officials explain, because the first stage main engine -- the dual-nozzle Russian-made RD-180 -- provides plenty of steering control during ascent. Engineers also note that two of the seven previous Atlas 5 launches have flown successfully with uneven numbers of solids attached to the first stage, including the commercial Inmarsat mission a year ago with two boosters strapped to the rocket's south side and one on the north; and January's New Horizons launch to Pluto with two on the south and three motors on the north.

After Wednesday's rollout to the launch pad, the mobile platform will be locked into position, the transporter carriages pulled away and propellant lines hooked up.

Thursday's countdown begins at 9:27 a.m. when the Atlas 5 is powered up. Fueling of the rocket with supercold liquid oxygen and liquid hydrogen starts just after 2:30 p.m.

A 10-minute planned built-in hold is scheduled at T-minus 4 minutes, beginning at 4:13 p.m., to give the launch team a chance to evaluate all systems before going into the final phase of the countdown.

The RD-180 engine ignites at T-minus 2.7 seconds, roaring with pad-shaking thunder while undergoing a check to ensure its vital signs are healthy. Then the command is issued to ignite the single solid rocket motor for liftoff.

The Aerojet-made solid booster will burn for about 95 seconds to generate a quarter-million pounds of thrust, on average, to assist the RD-180 in propelling the rocket skyward.

After the spent booster is jettisoned, the kerosene-fueled first stage will continue to fire for a couple of minutes before shutting down and separating. That leaves the hydrogen-fueled Centaur upper stage to ignite for a lengthy burn that will inject itself and ASTRA 1KR into a preliminary orbit with a high point of 13,945 miles, low point of 104 miles and inclination of 24.83 degrees.

Centaur completes its first burn over the Central Atlantic Ocean nearly 18 minutes after liftoff. The stage then coasts in the parking orbit for almost 90 minutes, cruising over Africa and the Western Indian Ocean before the Pratt & Whitney RL10 cryogenic engine is restarted.

That second Centaur firing will last a minute-and-a-half to send the 9,550-pound ASTRA spacecraft into a geosynchronous transfer orbit with an apogee of 22,237 miles, perigee of 3,860 miles and inclination of 23.97 degrees.

Deployment of the payload to complete the eighth Atlas 5 mission is expected an hour and 48 minutes after liftoff, or 6:15 p.m. given an on-time launch.

The satellite will use an onboard engine to circularize its orbit into a geostationary one, parking over the equator at 19.2 degrees East longitude to replace the aging ASTRA 1B and ASTRA 1C spacecraft launched in 1991 and 1993, respectively.

ASTRA 1KR was built by Lockheed Martin using the A2100AX model design. It is equipped with 32 Ku-band transponders to transmit the programming directly to small receiving dishes on homes across Europe.

The original ASTRA 1K craft was lost in a Russian Proton rocket launch failure three-and-a-half years ago.

http://www.spaceflightnow.com/

http://www.ilslaunch.com/newsarchives/newsreleases/rec336/

In Europe, New Skies NSS 7, transponder WHL3/EUH2 Ch 2, Ku-band digital, 338 degrees East, downlink frequency 11,073.500 (horizontal); symbol rate 6.1113, FEC 3/4.

ASTRA 1G at 19.2E downlink frequency: 12669.50 MHz / downlink polarization: vertical /transponder transmission rate: 22 MS/s QPSK FEC 5/6; Service name: ASTRA VISION 3

Test signals begin about 3:45 p.m. EDT (19:45 GMT).

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Hopefully coverage will match up to previous launches:
http://www.ilslaunch.com/launches/atlaslaunches/Atlas52/

Zaphod

http://streamvox.streamos.com/vyvx/ils042006/

ro2

Here's another one: http://abc2.eu/tv.asx

I like the onboard camera on the previous one.

Zaphod

Spaceflightnow reports everything is on track.

A reminder that GMT differs by an hour from Summertime.

http://www.spaceflightnow.com/atlas/av008/status.html

1859 GMT (2:59 p.m. EDT)

Ten percent of the first stage liquid oxygen tank has been filled so far. The stage's bronze skin is icing over as the supercold liquid oxygen flows into the vehicle.

1857 GMT (2:57 p.m. EDT)

Now 90 minutes to launch.

Zaphod

T-3 minutes

Zaphod

And liftoff ...

ro2

No onboard cameras during lift off! SES better get the wallet out next time

DMC

So.... this one isn't in the Pacific yet?

ro2

Not yet. They're showing the separation live at 11:09.

Zaphod

Successful separation.

Pity there was no onboard camera.

watty

Ironic since it full of Digital TV transmitters (I know they aren't available till the satellite is deployed).

Well it was a shock the original Hotbird & Astra launches failing. I'm sure a corporate sigh of releif that these two replacement launches are OK.

Zaphod

Spaceflightnow have added some pics to their website.