How NASA plans to reach deep space
Sen—Human spaceflight beyond low Earth orbit was brought into focus following the death of Neil Armstrong, the first human to set foot on the Moon. It is 40 years since a man last walked on the lunar surface and today no government or enterprise operates the technology that can follow in the footsteps of the Apollo astronauts.
However, much exploration of space beyond orbiting stations is planned in the coming years, from private companies seeking to land robots on the Moon and asteroids to China aiming for a manned lunar landing. As for NASA, it has been given a target by President Obama to send humans to an asteroid by 2025 and to Mars in the 2030s. To acheive this the US space agency is designing a new heavy lift rocket that can transport humans to deep space - including the Moon as well as asteroids and the Red Planet.
The proposed rocket, known as Space Launch System (SLS), passed a major review of its requirements last month, as reported by Sen. SLS is being desgined to launch the Orion spacecraft, also being developed by NASA, to the Moon and beyond.
The core stage of the launch vehicle will measure 200 feet (61 metres) by 27.5 feet (8.4 metres) and will contain liquid hydrogen and liquid oxygen to feed the rocket's RS-25 engines. The launcher will also be powered by two solid rocket boosters. RS-25 engines from the retired Space Shuttle fleet will be used for the first flew flights.
The SLS is being designed with two configurations, one that can lift 70 metric tons and a larger configuration with a second stage that will be capable of lifting 130 metric tons. In its larger configuration its lift capacity and - at 384 feet tall - its height will exceed the capabilities and size of the Dr Wernher von Braun designed Saturn V rocket that took the Apollo craft to the Moon. The Saturn V rocket stood 363 feet tall (110 metres) and could lift 120 metric tons to Low Earth Orbit.
The first test flight for SLS is scheduled for 2017. This week the space agency reported on the extensive wind tunnel tests that have been taking place in recent months at the Marshall Space Flight Center and Langley Research Center. At Marshall's Trisonic Wind Tunnel over 900 tests have been conducted on scaled down models of the SLS in various crew and cargo configurations to test the flight stability of SLS.
Further tests on larger models to understand the rocket's aerodynamics will take place at the agency's Langley Research Center wind tunnel, as well as that of Boeing, a prime contractor for the rocket build.
The biggest SLS wind tunnel model test to date is scheduled for mid-September. Langley's Transonic Dynamics Tunnel will test a 12 foot long model to evaluate the vehicle's aerodynamics.
A NASA statement on the wind tunnel testing said: "Each test moves the agency closer to giving the nation a launch capability to take humans farther than ever before. Designed to be flexible for launching spacecraft for crew and cargo missions, including NASA's Orion multipurpose vehicle, SLS will enable NASA to meet the president's goal of sending humans to an asteroid by 2025 and to Mars in the 2030s."
Meanwhile the spacecraft that SLS will launch into space, the Orion Multi-Purpose Crew Vehicle, has been undergoing parachute drop tests and drop tests into water, as the spacecraft is being designed to land in the ocean like the Apollo capsules that returned astronauts from the Moon.
Water impact test of an 18,000-pound (8,165 kilogram) test version of the Orion spacecraft at NASA's Langley Research Center on Thursday, August 23, 2012. Credit: NASA
The first unmanned test flight for Orion is scheduled to launch from Cape Canaveral Air Force Station in 2014. The spacecraft will be blasted 3,600 miles into space - 15 times farther than the orbit of the space station. The test flight should see Orion reach speeds of more than 20,000 mph before re-entering Earth’s atmosphere. This test will provide engineers with data on Orion’s performance during launch, re-entry and landing. The re-entry will enable NASA to assess the performance of its heat shield.
In 2017 NASA plan to launch Orion atop the Space Launch System rocket.
Whilst NASA concentrates on the Space Launch System rocket and Orion for deep space missions, its strategy for transporting crew and cargo to Low Earth Orbit and the International Space Station is to use private space companies including SpaceX, Orbital Sciences, Sierra Nevada Corporation and Boeing.