Zenit-2 for Commercial Comsat Launches

[Danderman]

Zenits topped with an escape stage are commonly used for launches to GTO. However, the current Zenit builders may no longer have access to escape stages, which are made in Russia, and will probably end Zenit production.

Another approach might be to use the standard 2 stage Zenit to boost comsats to a high LEO orbit, and let the comsat electric engines boost the spacecraft to GEO.  In fact, with sufficiently large prop tanks, such an arrangement might result in extra capacity, compared to SeaLaunch.

The trick is to view the Zenit vernier engines on the second stage as a virtual third stage; after the main engine turns off, the verniers could boost the payload into a 700 km x 700 km parking orbit (or even higher) after which the comsat would maneuver to altitude.

On advantage of this approach is that the Ukrainians might be able to develop a launch site on the western shore of the Black Sea, and launch the vehicle from there - with the first stage dropping into the Black Sea, and the second stage making orbit.  The launch site would be situated at 45 degrees latitude, or lower, resulting in greater performance for the vehicle than from Baikonur.

[Damon Hill]

Considering that the first and second stage engines are also built in Russia, Zenit is dead.  Which is too bad, because it's a good modern launch system.

[Danderman]

The second stage engine is actually produced in Dneprpetrovsk.

[Danderman]

The RD-171 first stage has only 1 customer and that is Zenit/Sea Launch. Even with hostilities, I suspect that Energomash would still sell the engines to their one customer.

The issue is that their customer has no customers.

[asmi]

The issue is that their customer has no customers.

No - the issue is that Yuzhmach has no money to pay for engines. I doubt Energomash would have refused to sell them, but my understanding is that before they shipped engines in advance, and got paid once the launch has happened. Now this approach is too risky financially.

[D_Dom]

The trick is to view the Zenit vernier engines on the second stage as a virtual third stage; after the main engine turns off, the verniers could boost the payload into a 700 km x 700 km parking orbit (or even higher) after which the comsat would maneuver to altitude.

Embarrassed to report I haven't memorized the capabilities of our second stage. Not at work this week with no access to the users guide I find this;
 http://www.spaceflight101.com/zenit-3slb.html
Which is full of old information but seems to imply second stage verniers have Isp comparable to mains. Interesting...