Wednesday, February 02, 2011

USSTRATCOM ceases publication of Ofeq satellite elements

Phillip Clark has reported that Space-Track ceased issuing orbital data for the four Ofeq satellites currently in orbit on January 31st.

27434 2002-025A Ofeq 5
31601 2007-025A Ofeq 7
32476 2008-002A Ofeq 8 (TecSAR/Polaris)
36608 2010-031A Ofeq 9

(TecSAR was renamed “Ofeq 8” just before the Ofeq 9 launch, possibly to overcome the “curse of even-numbered Ofeq satellites”, failing to reach orbit.)

Orbital data for the two EROS satellites are still being issued, presumably because these are commercial payloads: also the data for the Shavit-2 third stage from the Ofeq 9 launch are still appearing.

Ofeq, also spelled Offek or Ofek (Hebrew: אופק‎, lit. Horizon) is the designation of a series of Israeli reconnaissance satellites first launched in 1988. All Ofeq satellites have been carried on top of Shavit rockets from Palmachim Airbase in Israel, on the Mediterranean coast. The Low Earth Orbit satellites complete one earth orbit every 90 minutes. The satellite launches made Israel only the eighth nation to gain an indigenous launch capability. Both the satellites and the launchers were designed and manufactured by Israel Aerospace Industries (IAI) with Elbit Systems' El-Op division supplying the optical payload.

While exact technical details and capabilities are classified, it is assumed that the Ofeq satellites have ultraviolet and visible imaging sensors, and an effective operational lifespan of 1-3 years. Some early reports stated the reconnaissance capabilities as such that would allow "reading license plates in Baghdad", but that can be ruled out on grounds of physical optics. Other reports more plausibly place the imaging resolution at 0.8 meters for Ofeq 5.

Most non-Israeli satellites are launched eastward to gain a boost from the Earth's rotational speed. However, Ofeq satellites are launched westward (retrograde orbit) over the Mediterranean to avoid flying over, and dropping spent rocket stages over, populated areas in Israel and neighboring Arab countries. Other Israeli satellites (such as the Amos series) are launched from locations in other countries.

Ofeq's east-to-west orbit at 36 degrees inclination is phased to give optimal daylight coverage of the Middle East. Ofeq makes a half-dozen or so daylight passes per day over Israel and the surrounding countries, whereas U.S. and Russian spysats only get one or two passes per day from their higher inclination orbits. This optimal coverage degrades after several months, nevertheless keeping a very good coverage of the Middle East.

Ofeq 5, was launched 28 May 2002. The 300 kg Ofeq 5 orbited the earth on a course with a perigee of 262 km and an apogee of 774 km, bent around 143.5 degrees. During the course of its mission, its perigee was raised to 369 km and its apogee was lowered on 771 kilometers, in an attempt to prolong the satellite's lifespan. Some observers believe that the 300 kg weight of the satellite, combined with the additional propulsive requirements of the retrograde orbit, constitute a de facto demonstration of the Shavit's ICBM potential.

Ofeq 7 was successfully launched on June 11, 2007.

Ofeq 8 designation is used for the TecSAR synthetic aperture radar satellite launched by an Indian rocket on 21 January 2008.

Ofeq 9 was successfully launched on June 22, 2010 from Palmachim Air Base.