Darkness for New Dawn Satellite?

Posted by Sam Churchill on

Satellite fleet operator Intelsat on May 10 said it will give ground teams another week or so to try to shake free a stuck antenna on Orbital Sciences’ New Dawn satellite. It is now May 19th and no word has apparently been forthcoming from either Intelsat or Orbital. That means satellite operators may now be abandoning their efforts on that antenna, and turning their attention to deploying the satellite’s other reflector antenna, which they assume will function normally.

The Intelsat New Dawn satellite was placed into geostationary transfer orbit April 22. The satellite’s final operating location, at 32.8 degrees east, is scheduled to serve mainly an African audience.

Gently shaking the satellite, and orienting it in such a way as to expose the stuck antenna to the sun’s heat, will be harder to do once the reflector on the other side of the satellite, which directs the Ku-band payload of 24 transponders, is deployed.

Intelsat Chief Executive David McGlade said the company, along with satellite manufacturer Orbital Sciences of Dulles, Va., has been “working day and night” on maneuvers intended to use relatively sudden movements of the satellite, and exposure to temperature extremes, to free the reflector, which directs the satellite’s C-band payload of 28 transponders.

For more than two weeks after the effort began, the antenna apparently remains stuck in the same position, folded against the satellite as it was for launch, despite the apparently successful release of pins that are intended to hold the antenna close to the satellite’s body.

Why the antenna did not spring loose on ejection of the pins remains a mystery. It might be time to call in the Geosync Spies.

Lightsquared also had a problem unfurling their massive antenna. SkyTerra 1, was successfully launched on on November 14, 2010. All was going swimmingly until Boeing tried to unfurl the massive 22 meter (75 foot) antenna. For 10-days managers thought the mission might be lost. The antenna, the largest commercial antenna ever launched in space, was gently “shaken” by ground commands, which stirred the spacecraft into action, releasing the antenna.

Orbcomm has had a string of bad luck lately. Orbcomm’s AIS satellites, capable of monitoring maritime traffic, ceased functioning on February 1st, but the company expects to replace it by this summer. Space-based AIS provides global coverage of maritime activity, re-transmiting GPS coordinates, along with bearing and speed.

Orbcomm had been under contract to the U.S. Coast Guard and is making AIS capacity a feature on all 18 of its second-generation satellites (pdf), which are scheduled to be launched starting late this year. Sierra Nevada Space Systems of Louisville, Colo., is building the 18 2nd generation satellites under a $130 million contract that includes options to build up to 30 more.

These satellites will be launched aboard multiple Falcon 1e launch vehicles. The Falcon 9 rocket is the SpaceX heavier lifter.

As part of its settlement with OHB Technology of Bremen, Germany, following the failure of the six satellites launched in June 2008, OHB and its Luxspace affiliate are building two dedicated AIS spacecraft for Orbcomm. These satellites are scheduled for launch starting by June, Orbcomm said in a filing with the U.S. Securities and Exchange Commission.

Space-based AIS is becoming a highly competitive market, with Orbcomm and Com Dev of Canada, through its exactEarth subsidiary, racing to put AIS capacity in orbit.

ExactEarth is targeting June 1 for their AIS payload piggybacking on an Indian satellite to enter service, following their six-week check out period. COM DEV’s core technology is said to enable ExactEarth to filter out all but a very specific VHF portion of the signals dedicated to AIS. To achieve global AIS coverage with a latency of about 10 minutes about 30 satellites are required.

COM DEV has calculated that only three satellites are needed to provide a six hour “revisit time”. According to CEO John Keating, “If you put three satellites in polar orbits that takes 100 minutes to complete, 120 degrees apart from one another, then [due to the earth’s rotation] you can see any point on earth within six hours – you may be over the poles once every 30 minutes, but you are everywhere over the equator once every six hours.”

ExactEarth AIS satellites pass over Norway’s Svalbard Earth Station every 90 to 100 minutes. AIS tracks vessel movements in near real-time and updates every two minutes or so when near shore stations.

The International Space Station (ISS) represents an ideal platform for testing AIS receivers due to its orbit: its 400 km altitude is low enough to give a high probability of ship detection and it also passes across many of the world’s most densely populated shipping lanes.

Norway’s NORAIS and Luxembourg’s LUXAIS have been used on the ISS. They were connected to an AIS antenna constructed by the ARISS (Amateur Radio on the International Space Station) community.

Orbcomm-1 satellites make up most of the current Orbcomm constellation of about 35 minisatellites. Their next generation will incorporate AIS radios.

Related DailyWireless stories include; Lightsquared Unfurled, Satellite with 328 ft Antenna to Launch , Geosync Spies, F.I.A. FUBAR, Advanced EHF – Wait for It, AEHF Satellite – Billion Dollar Brick?, U.S. Antisatellite Weapon to be Tested, Nuclear Powered Spacecraft, Zombie Satellite Out of Control, Satellites Collide,

Posted by Sam Churchill on Thursday, May 19th, 2011 at 9:55 am .

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