Sunday, December 7, 2014

Orion - NASA spacecraft to take Humans to Mars achieves success on maiden test flight

Orion, the spacecraft aimed to carry the first humans to Mars one day, ventured beyond the skies on its maiden flight on December 05, 2014. It was an experimental test flight launched from Cape Canaveral Air Force Station, Florida, America’s most used space launch port.

The flight has been termed near perfect as per National Aeronautics & Space Administration’s (NASA) mission control center once Orion successfully splashed down into the Pacific Ocean near California after orbiting the earth twice.


Orion taking off from Cape Canaveral on Dec 05 on board the Delta IV Heavy launch Vehicle; Courtesy - Space.com, NASA


This flight only included the crew module which is meant for housing the astronauts during deep space voyages to asteroids and Mars. The fully functional Orion will contain the crew module developed by Lockheed Martin, the service module developed by Airbus and a Launch Abort System (LAS) which will allow astronauts to detach the crew module from Orion assembly and abort mission in case of a launch failure.

The Orion made its reentry into earth’s atmosphere at a speed of 20,000 miles per hour (36,000 km per hour) and had a mass of 21,000 pounds (9530 kg). It slowed down to a speed of 300 miles per hour when the system of 11 parachutes took over to bring it safely down to 20 miles per hour and drop it in the Pacific. This first flight was called Exploration Flight Test-1 and cost $370 million



While it was not a red letter day in NASA’s history, the event has created some euphoria among the public for the world’s largest and most advanced space agency which has been plagued by budget constraints in last 10 years.

Initially, Orion was a part of the Constellation Program, started by President George W Bush in 2004 to take Americans back to the moon by 2020 and eventually to Mars.

But Constellation was cancelled by current President Barack Obama in 2010 on the recommendation of an expert committee that the program was not financially feasible under then NASA budgets in the near future since then global recession and the wars in Iraq and Afghanistan had put huge pressure on US government annual budgets.

Since the golden age of space exploration in the 1960s and early 70s when US & Soviet Union locked horns in a fierce space race. Soviet Union took the first humans into space while NASA took the first humans to moon on a series of Apollo spacecraft missions. But since then, it has been a downhill slide for NASA.

The last person walked on the moon in 1972 as the Apollo program was terminated post that both due to budget constraints and the cancellation of Soviet Union’s fledgling moon program.

Apollo 17 Scientific Instrument Module bay on the Service Module, seen from the Lunar Module in orbit around the Moon; Courtesy - NASA

Eugene Cernan, the last human to walk on the moon performing the last lunar excursion, December 13, 1972; Courtesy - NASA
Apollo was replaced by the Space Shuttle, a semi reusable space launch vehicle (aka rocket) that took humans back only in the low earth orbit (LEO altitude range is 160km to 2000 km above earth’s surface). The first operational flight mission of the space shuttle was in 1982 and it was retired in 2011 after 135 missions.

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The shuttle, partly similar to a plane, used to lift vertically on attached combinations of solid and liquid booster rockets and upon reentry and descent into earth’s atmosphere, used to glide down and land horizontally on a special runway partly reminiscent of landing a small plane.

The STS-133 mission, Space Shuttle Discovery touches down similar to a small plane at the Shuttle Landing Facility; Courtesy - NASA/Kim Shiflett 
The Obama administration initiated and US Congress passed legislation in 2010 mandating NASA to create a new deep space launch vehicle called Space Launch System (SLS) that can carry Americans in Orion beyond LEO and eventually to Mars. The future travel to and from LEO was targeted through the commercial crew and cargo development programs (the economics and financial aspects of US space program and the private sector aiming at Mars will be dealt with in a future Blog post)

Orion aimed at carrying 3 humans to moon under the Constellation program. Then, the new NASA Act passed by US Congress in 2010 salvaged Orion and made some modifications to enable it to carry 4 humans not just to the ISS but up to Mars using the under development SLS rocket.

Artist's rendering of Space Launch System (SLS) After Launch-20140827; Courtesy - NASA/MSFC & licensed under Public domain via Wikimedia Commons 
Thus, the December 05 Orion’s maiden flight was launched on the Delta IV Heavy rocket belonging to the Delta family of expendable (use once & throw) launch rockets developed by United Launch Alliance, a joint venture between Boeing and Lockheed Martin. The Delta family has been mostly used to launch US military and navigation satellites.

Only rockets carrying telescopes, satellites and landers & robotic probes to moon, Mars and other destinations in the solar system have ever crossed LEO. And this is where Orion’s flight is deemed historic.

Orion reached an altitude of 3630 miles (5790 km), over 15 times higher than any human spacecraft has reached since the last Apollo (Apollo 17) landing in 1972. The space shuttle only ever reached a maximum of 350 km in its 135 mission history. However, Orion’s flight was not aimed at breaking a four decade plus hiatus for a human spacecraft to go beyond LEO.

The primary objective of this flight was to test Orion’s heat shield upon the craft’s reentry into the earth’s atmosphere where it is engulfed by a ball of plasma attemperatures in excess of 4000 degree Fahrenheit. The space shuttle experienced temperatures up to 1500 degree Fahrenheit (º F) only.

NASA originally targeted a heat shield made of a newly developed composite material but after a lot of R&D, concluded that Avcoat, the same coating which protected the Apollo spacecrafts upon reentry over 4 decades ago,  is still the best.

Some minor changes were made in the new shield like 30 percent extra material to fit onto the larger sized Orion. The coating had not been in manufacturing for decades and it took NASA 8 months to redevelop it.

The shield consists of a fiberglass overlay with 320,000 cells which are filled with Avcoat. This fiberglass overlay is built around a titanium skeleton upon which a carbon fiber skin is fitted. The stand out property of the heat shield is that a significant percentage (20 percent in this test flight) of the Avcoat coating burns away in the extreme heat generated by the plasma ball surrounding the spacecraft during descent through the atmosphere.



But flights to moon and Mars will be an entirely different ballgame. An Orion capsule returning from the moon will hit the Earth’s atmosphere at about 25,000 miles per hour raising temperatures upto 5,000 º F.

If returning from Mars, it’ll make reentry at a mind boggling 33,500 miles per hour, highest speed ever for a man-made object re-entering earth’s atmosphere. The temperature of the plasma ball will be a scorching 5,500 º F.

While there’s no way to test a return from Mars reentry conditions, the test flight in 2018 is planned around the moon and will be launched on SLS. Then comes a series of LEO missions on SLS-Orion followed by the major proposed asteroid mission to be carried out by 2025.

In this, SLS is supposed to lasso an asteroid via a robotic spacecraft and put it in orbit around moon and then the first humans aim to land on the asteroid to conduct experiments and collect samples. The asteroid mission is aimed to be the final test bed for humanity’s odyssey to Mars.

The second major objective of Orion’s flight was to test the system of 11 parachutes which were deployed like a choreographed ballet sequence beginning at an altitude of 20,000 feet (around 3.8 miles or 6.1 km) when the capsule had slowed down to a speed of 300 miles per hour.


Orion Crew Module descending through the last 3.8 miles (6.1 km) after the system of parachutes were deployed in a unique sequence; Courtesy - NASA
Apart from the above major objectives, Orion crew capsule had 1200 sensors fitted on it to record flight data on critical variables like temperature, pressure, speed and radiation. The next few years will involve data analysis of values of all the variables recorded by the sensors to prepare detailed knowledge about flight conditions and make necessary changes for next test flight scheduled for 2018.
  
As Orion lay peacefully in the waters of the Pacific Ocean waiting to be captured, the officials at NASA know that this is just the beginning of next phase of a decades’ long journey. A recent Congressional committee came out with a reportstating that NASA’s SLS launch vehicle and Orion crew capsule program iswoefully underfunded and major technological challenges remain before it can ever take off to Mars – some call it a nonstarter.

On the technological front, cosmic and solar radiation remains the biggest obstacle. The amount of radiation that astronauts’ bodies are estimated to absorb on a trip to Mars with the same shielding that was used on the Apollo moon missions will prove to be lethal. Thus a radiation shielding of an entirely new structure and size is required.

One of the most oft discussed radiation shielding solutions is water. But Orion will need a water shield atleast 1 meter thick for the least time consuming trajectory to and from Mars. That largely reduces the amount of payload that can be carried to Mars which would include astronauts’ belongings, food and all landing and habitat equipment to live on Mars. Most research into other radiation shielding materials has not reached beyond lab testing.

Then there is the issue of the astronauts spending the longest ever time in micro gravity conditions experienced by any human. Micro gravity makes the muscles and bones to atrophy and there’s no experiment conducted or data available as yet that can simulate the micro gravity conditions for both the onward and return journeys.

Thus this is one small step for humanity especially NASA and it’ll take hundreds of such steps before we make the next giant leap to Mars.


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