Author Topic: Zenit 3SL vs 3SLB (Read 4759 times)

Spirit · « **on:** 04/29/2008 12:16 pm »

Is there any difference between Zenit 3SL and Zenit 3SLB or the "B" just indicates that it will be launched from Baikonur?

It seems that after introducing the SLB, Zenit 3 can fly almost every month. What is the difference in the payload that SL and SLB can launch, having in mind that they are being launched from different latitudes?

sammie · « **Reply #1 on:** 04/29/2008 04:23 pm »

There are a number of differences, the biggest one being the lesser involvement of Boeing as a partner on the project.

From the Sea Launch website the following differences can be extracted:

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Using existing Zenit infrastructure at the Baikonur Space Center, the Land Launch system is based on a modified version of the proven Sea Launch vehicle, the three-stage Zenit-3SL. Land Launch's Zenit-3SLB vehicle addresses the launch needs of commercial satellites weighing up to three-and-a-half metric tonnes. The two-stage Zenit-2SLB is also available for lifting payloads up to thirteen metric tonnes to inclined low Earth orbits.

The fairings represent the most significance difference. In place of the Boeing-made fairing used on Sea Launch, the Zenit-3SLB adopts a 4-meter fairing made by NPO Lavochkin. It is in current production and has been flight-proven with the Block DM. The Zenit-2SLB fairing is an improved version of the heritage Zenit-2 fairing.

These are the hardware differences, I'm not to sure how things are organized personell and responsibility wise....

Jim · « **Reply #2 on:** 04/29/2008 04:44 pm »

I would say that Boeing has lesser involvement, they just aren't supplying the fairing. Landlaunch is still 40% Boeing

Nick L. · « **Reply #3 on:** 04/29/2008 04:51 pm »

The 3SLB has a lighter third stage (fixed instead of deployable antennas, removal of some tanks, and some other changes) in addition to the different fairing.

Danderman · « **Reply #4 on:** 04/30/2008 03:22 am »

Is the mysterious Lavochkin fairing the one that is used on Proton?

zaitcev · « **Reply #5 on:** 04/30/2008 03:50 am »

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Danderman - 29/4/2008 8:22 PM
Is the mysterious Lavochkin fairing the one that is used on Proton?

Look at this:
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=10504&mid=244791#M244791
For some reason, the forum software bumps to the bottom of the thread. Rewind to page 2 and search the message by Stan Black:

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This fairing was used for Yamal, looks similiar to the Khrunichev but what gives it away is that on the DM there is a tapered section placed around the torus instrument section.

sammie · « **Reply #6 on:** 05/02/2008 01:08 pm »

some more on the upperstage differences from spaceflight now

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The Block DM-SLB upper stage also endured several modifications focused on reducing the rocket's weight. The changes shed more than 4,000 pounds from the similar stage used on Sea Launch missions.

Engineers swapped the stage's single avionics bay with several lightweight containers, replaced a deployable antenna and telemetry system with fixed antennas, removed a set of fuel tanks for the rocket's attitude control system, and took out a command system that was deemed unnecessary, according to Sea Launch.

Engineers also added two control jets to the stage to increase the rocket's reliability. The small thrusters will help settle the stage's kerosene and liquid oxygen propellants before the mission's final major engine firing to decrease the amount of fuel needed for the burn to begin.