Jupiter (rocket family)

The Jupiter family of super heavy-lift launch vehicles was part of the proposed DIRECT Shuttle-Derived Launch Vehicle architecture. It was intended to be the alternative to the Ares I and Ares V rockets which were under development for the US Project Constellation. The Jupiter family of super heavy-lift launch vehicles was part of the proposed DIRECT Shuttle-Derived Launch Vehicle architecture. It was intended to be the alternative to the Ares I and Ares V rockets which were under development for the US Project Constellation. Major benefits were projected from re-using as much hardware and facilities from the Space Shuttle program as possible, including cost savings, experience with existing hardware, and preserving the workforce. Jupiter was designed to be a high-commonality family of rockets, adapted closely from existing Shuttle systems. Each Jupiter launch vehicle would use a 'common core stage' consisting of a tank structure based closely on the existing Space Shuttle External Tank with a pair of standard four-segment Solid Rocket Boosters (SRBs) mounted at the sides as on the Space Shuttle. Up to four Space Shuttle Main Engines (SSMEs) from the Space Shuttle Orbiter would be attached to the bottom of the tank and would be expended along with the tank. For heavier payloads a proposed Jupiter Upper Stage (JUS) would be added atop the tank structure. For extra-planetary expeditions, the JUS would serve in a role similar to the Earth Departure Stage planned for Ares V. DIRECT purposefully specified existing components for the launch vehicles, but contended that improvements such as the more powerful five-segment SRB or the J-2X upper stage engine could have been incorporated. Crews would be carried atop the launch vehicle in NASA's planned Orion Crew Exploration Vehicle. Cargo, whether carried under Orion or alone on a cargo-only launch, would be enclosed by a payload fairing. Many configurations of Jupiter were projected, with the May 2009 DIRECT version 3.0 proposal recommending two: the Jupiter-130 and Jupiter-246, with claimed lift capacities exceeding 60 and 90 tonnes (t), respectively, to low Earth orbit.. DIRECT proposed that the Jupiter-130 be the first configuration developed, with the goal of becoming operational within four years of the start of the development program. The Jupiter-130 would have consisted of the Jupiter common core stage with one SSME removed, no upper stage, and a payload fairing on top. '130' stands for one cryogenic core stage, three main engines, and zero upper-stage engines. Initial launches would rotate crews and bring cargo to the International Space Station, a function currently carried out by Soyuz rockets. DIRECT calculations indicated that the Jupiter-130 would have been able to deliver between over 60 t and over 70 t of cargo or cargo and crew to a variety of circular and elliptical inclined low Earth orbits. When the mass of the proposed Orion spacecraft and crew is subtracted (18 - 22 t depending on the mission), the remainder compared favorably with the approximately 25 t cargo capacity of the Space Shuttle, and the lack of capacity of Ares I besides the Orion spacecraft. The Jupiter-246 would have used four Space Shuttle Main Engines (SSMEs) in the common core stage with an upper stage, informally called the Jupiter Upper Stage (JUS). The Jupiter-246 would use six RL10B-2 engines on the upper stage. '246' stands for two cryogenic stages, four main engines, and six upper stage engines. The primary role for the Jupiter-246 would be to launch heavier cargo as well as crew and cargo for lunar missions. Because the Jupiter-246 would have used four SSMEs on propellant tanks originally sized for three engines, the core stage propellant would be depleted before achieving low Earth orbit, and a large capacity upper stage would deliver payload into orbit. Launched with a partial upper stage propellant load of 75 t, a Jupiter-246 could deliver over 84 t of crew and cargo to a circular 241 km (130 nmi), 29° inclined orbit. Launched with no crew or payload, the same 75 t of propellant could deliver an additional 100 t of propellant to the same orbit. The total JUS capacity was to be approximately 175 t. For lunar missions where the JUS is to serve as the Earth departure stage, a full load of 175 t of propellant would be launched and 75 t would be consumed in achieving low Earth orbit, leaving 100 t available for the Earth departure burn.