The Space Shuttle is used to build and transport the crew to the ISS and for servicing missions to Hubble. However, its operation is extremely expensive, although its use was supposed to relieve NASA’s budget expenses. Reusability comes at a high cost of complexity. And it costs far more to disassemble, repair, reassemble, and maintain support devices for something so complex than to build a simpler, single-use device. That’s why NASA is returning to rockets and intends to give up on the space shuttle, the greatest technical miracle.
The Ares launchers are supposed to be the best of the Space Shuttle and Saturn launchers. The Ares rockets will deliver 130 tonnes to low Earth orbit, compared to the 24.4 tonnes provided by the Space Shuttle. The volume will also be larger. Ares will provide a transport space of 16 meters long and 10 meters in diameter, Space Shuttle provides a length of 18 meters and a diameter of 4.5 meters.
Despite their ability to carry heavier or bulkier payloads, Ares launchers will have several major drawbacks. First of all, it will not be possible to carry large loads at the same time as the crew. While the Ares launcher will be in two basic versions, Ares I (Ares 1) for manned flights and Ares V (Ares 5) for carrying heavy payloads, the Space Shuttle managed both tasks at once, and could still deliver the large payload from orbit back to Earth (not that it would ever be used). The payload of the Ares I rocket is 25 tons to low orbit, which falls on the manned module.
| Property | Delta IV Heavy | Saturn V | Space Shuttle | Ares I | Ares V |
|---|---|---|---|---|---|
| Early development | 1957 | 1962 | 1972 | 2005 | 2005 |
| First use | 17. 1. 2009 | 16. 8. 1969 | 12. 4. 1981 | – | – |
| Height | 77.2 m | 111 m | 56.1 m | 95 m | 110 m |
| Starting weight | 0,733 kt | 2,725 kt | 2,030 kt | 4,400 kt | 16,314 kt |
The Space Shuttle carried parts from the International Space Station, the Hubble Space Telescope, the Galileo probe, the Magellan probe, the Chandra X-ray observatory and the Compton gamma-ray observatory. It also carried out two purely scientific missions and four servicing missions to Hubble. The Ares launchers will enable lunar missions and the launch of the ATLAS telescope.
Ares I
The first stage of the rocket consists of a single five-segment SRB, derived from an older four-segment version from the Space Shuttle, with improved flight electronics for five uses. In two and a half minutes, it accelerates the rocket to a speed of Mach 4.8 and takes it to an altitude of 58 km. The second stage, with a diameter of 5.48 meters, will accelerate the J-2X engine on liquid hydrogen and oxygen. It is a modified J-2 engine from the second stage of the Saturn V rocket. It will carry the Orion ship to an altitude of 129 km. It will then be launched into orbit at an altitude of 290 km by its own propulsion.
Ares V
The first stage of the rocket, with a diameter of 10 and a height of 110 meters, consists of five RS-68B engines running on liquid hydrogen and oxygen with a tank and a pair of lateral five-segment SRBs. The second stage, like the Ares I, will accelerate the J-2X engine to liquid hydrogen and oxygen.
Orion
Orion is a spacecraft launched by the Ares I rocket to transport a crew to the Moon, or a crew or cargo to the ISS. The ship consists of four main parts. On top is the rescue system tower, below it is the crew cabin connected to the cylindrical service module, which contains the ship’s main engines on MMH and N2O4. The connection to the rocket is provided by a transition adapter. The ship will be able to park at the ISS for 210 days.
J-2X
This engine is based on two predecessors. The first is the J-2 engine from the second stage of the Saturn V rocket. The second is its simplified version J-2S tested in the early 1970s, but which was never used. Unlike its predecessors, it has to operate at much higher temperatures, at higher pressure and flow speeds. The thrust of the J-2 engine in vacuum, which is 1.033 MN, increases the J-2X to 1.108 MN. The engine is approximately 4.7 m long and the largest nozzle diameter is 1.04 m. The weight is 2.477 tons. The nozzle is cooled by supercooled fuel. Compared to its predecessor, it has been lengthened, which has increased the efficiency of the engine. By being able to change the ratio of liquid oxygen to hydrogen, the engine can operate both in and out of the atmosphere. After launching the payload (Orion module or Ares V payload) into orbit through the upper stage, it will re-enter the Earth’s atmosphere and fall into the Indian Ocean. No part will be reused. The manufacturer is Pratt & Whitney Rocketdyne of Canoga Park, based in California. The company has built J-2 engines for the Saturn V and has more than half a century of experience in the space program.
RS-68B
The RS-68B engines are improvements to the RS-68 engines from the Delta IV rocket developed in the 1990s for the U.S. Air Force. They are manufactured by Rocketdyne in California. The engine is characterized by its simplicity, low price and reliability. Compared to the SSME engine, it has 80% fewer components. However, it pays for this with a 10% lower specific impulse and a 30% worse thrust-to-weight ratio. The cooling medium of the combustion chamber does not flow in tubes wrapped around its wall, but through channels created by separating plates between two shells. This solution applied in the Energia missiles is heavier, but significantly simpler and cheaper. The nozzle is protected against heat by a melting material. The ratio of pumped hydrogen to oxygen is 1:6. The thrust of the engine in vacuum is 3.312 MN. Its weight is 6.597 kt and the nozzle has a diameter of 2.4 m.