Payload on the latest Delta IV launch?

[Sentinel Chicken]

Well, the forum title does say "General Aircraft Discussion" but the heading above that says "Aerospace" and what's cooler than a large explosive fuel filled vessel spewing tons of flame and noise to reach orbit, right?

I'm curious as to what might have been the secret USAF satellite orbited on last night's Delta IV launch from Vandenberg AFB. The one photo supposedly of the vehicle shows that it's not a Delta IV Heavy but one the configurations that has the core booster with two smaller solid strap-on boosters. I don't think that's got the power to put a KH-series PHOTOINT bird into orbit as those were previously orbited by Titan IV/Centaurs.

Which brings up my second question- can a KH-series satellite be carried by a Delta IV Heavy? I've been trying to find the measurements of the payload shroud of the Delta IV Heavy and the Titan IV/Centaur and I don't think the Delta IV is wide enough.

 

[Andreas Parsch]

Which brings up my second question- can a KH-series satellite be carried by a Delta IV Heavy? I've been trying to find the measurements of the payload shroud of the Delta IV Heavy and the Titan IV/Centaur and I don't think the Delta IV is wide enough.

The diameter of the payload shroud of the Titan IV/Centaur was 4.30 m, while that of the Delta IV Medium (5,x) and Heavy is 5.0 m (same for the Atlas V, BTW). I don't have data for the usable length, but the Delta IV Heavy and Atlas V payload sections don't look shorter than that of the Titan IV/Centaur. And given the fact that the Delta IV and Atlas V were developed for the Air Force EELV requirement, I'd be surprised if they couldn't launch whatever the USAF has in mind for the foreseeable future.

 

[Sentinel Chicken]

Thank you for the clarification, Andreas. I did some more digging this morning comparing the Delta IV and the Titan IV/Centaur in terms of payloads to LEO:

Titan IV/Centaur: 39000 lbs
Titan IV/Centaur/SMRU: 47800 lbs
Delta IV Heavy: 50800 lbs
Delta IV Medium+ (5,4): 25300 lbs

Sources: http://www.losangeles.af.mil/SMC/PA/Fact_Sheets/ttn4_fs.htm
Sources2: http://www.boeing.com/defense-space/space/delta/backgrounders/delta_4_backgrounder.htm

 

[sferrin]

The Atlas V Heavy (if they ever develope it) would be right there in the ballpark of the Titan IV and Delta IV Heavy too.

 

[Sentinel Chicken]

The Atlas V Heavy is one impressive rocket, very similar to the Delta IV Heavy in configuration- estimated 50000 lbs in LEO from most sources of information. Does anyone know off hand what the Saturn V's LEO payload capacity is? Only one Saturn V did an LEO mission, that was to launch Skylab.

EDIT: According the Mark Wade's site, Encyclopedia Astronautica, Skylab had a mass of 168201 lbs and the Saturn V that placed it into orbit consisted only of the first two stages.

 

[sferrin]

I've seen lots of figures from 235,000lbs all the way up to 285,000lbs. Scott Lowther would probably be the one to ask.

 

[Matej]

Payload of the Delta-4 differs by using different stages, their number, engines, upper stages... So some basic facts (from my materials):

Delta 4 Heavy (3 x CBC with RS-68 engines, second is Delta 4H-2 with RL-10B-2 engine) - 25 800 kg to LEO

Titan 4B (two SRMU, two LR87-AJ-11 engines at first stage and one LR91-AJ-11 on second stage) - 21 680 kg to LEO

Atlas-5 config. 552 (till now without flight test) - 20 520 kg

Space Shuttle (that differs shuttle to shuttle, biggest (theoretical) payload can carry Endeavour) - 24 400 kg to LEO