Monday, February 2, 2015

Ariane 5 Core plus 4 Ariane 4 side-boosters as a manned launcher.

Copyright 2015 Robert Clark

  In the blog post "Ariane 4 for European manned spaceflight", I suggested resurrecting the Ariane 4 to produce a European manned launcher. In the blog post "A half-size Ariane for manned spaceflight", I suggested using a half-size Ariane 5, so as to be loftable by a single Vulcain 2, to serve as a manned launcher.

 Here, I'll suggest using a full Ariane 5 core but using 4 Ariane 4 liquid side boosters for a manned launcher. I'll use the smaller Ariane 5 "G" version to be loftable by the boosters and the single Vulcain 2 engine. By the on the Ariane 5G, the core has a 12 metric ton (mT) dry mass and a 158 mT propellant mass. By the Astronautix page on the Vulcain 2 used on the core, it had a 1,350 kN vacuum thrust and 434 s vacuum Isp.

 For the liquid-side boosters from the Ariane 4, they had a 4,493 kg dry mass and 39,279 kg propellant mass. The Viking 5C engine used had a 752 kN vacuum thrust and a 278 s vacuum Isp. Plugging these numbers into Dr. John Schilling's Launch Performance Calculator gives the results:

Mission Performance:
Launch Vehicle:   User-Defined Launch Vehicle
Launch Site:   Guiana Space Center (Kourou)
Destination Orbit:  185 x 185 km, 5 deg
Estimated Payload:   15537 kg
95% Confidence Interval:   11748 - 20004 kg

"Payload" refers to complete payload system weight, including any necessary payload attachment fittings or multiple payload adapters
This is an estimate based on the best publicly-available engineering and performance data, and should not be used for detailed mission planning. Operational constraints may reduce performance or preclude this mission.

 The 15.5 mT payload is surprisingly high. Note this is without even using an upper stage.

   Bob Clark

UPDATE, February 10, 2015:

 The liquid-fueled boosters used on the ISRO's GSLV launcher are virtually identical to those used on the Ariane 4, so could be used for the purpose. Indeed the Vikas engines used on the GSLV were copied from the Viking engines used on the Ariane 4 as they were produced under license from the ESA:

GSLV Launch Vehicle Information.
Photo: Indian Space Research Organization

 Also, at a 15,500 kg payload capacity this Ariane 5 core plus Ariane 4 side-booster launcher could loft the Sierra Nevada Dream Chaser, at 11,300 kg.

 European companies are researching with Sierra Nevada the possibility of using the Dream Chaser as a manned spacecraft.

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