The most recent issue of Science News (18 December 2010) has the following notes from 17 December 1960:
However, if you want to travel to the Moon or journey anywhere within the Solar System, Galactic Cosmic Radiation will require that the human crew is protected. Let’s take a look at the problem and the research required to test and implement solutions.
The GCR problem arises from interstellar atomic nuclei traveling near the speed of light striking the structure of a spacecraft. The resulting shower of secondary particles cause radiation damage. The Earth is protected by the Van Allen belts and a deep atmosphere. Brief journeys such as an Apollo mission does not expose the astronaut to dangerous dosages. However, astronauts on such a journey are at risk from Solar flares (Solar Particle Events – SPE). SPEs can be mitigated with layers of hydrogen rich materials such as polyethylene or water. GCRs, however, require spaceships on long journeys of more than 100 days, or habitats on the Lunar or Martian surface, to be surrounded by tens of meters of water for passive protection, or magnetic shields for active protection. Either solution is extremely heavy and makes space flight prohibitive in terms of propellant requirements.
The Source of GCR
Galactic Cosmic Rays come from outside our Solar System, but from within our galaxy, the Milky Way. They are comprised of atomic nuclei that have been stripped of their electrons. These nuclei can be any element. Common elements are carbon, oxygen, magnesium, silicon, and iron with similar abundances as the Solar System. Lithium, Berylium and Boron are overabundant relative to the Solar System ratios.
The Shielding Problem
Early on, it was suggested that cosmic rays could penetrate the Apollo spacecraft. From “Biomedical Results of Apollo” section IV, chapter 2, Apollo Light Flash Investigations we have the following account:
When Galactic Cosmic Rays collide with another atom, such as those contained in the Aluminum, Stainless Steel or Titanium structures of a spacecraft, they can create a shower of secondary particles, These secondary particles cause radiation damage in living organisms (humans).
The problem is creating sufficiently powerful barriers to these extremely energetic nuclei.
* The Falcon 9 rocket performed nearly flawlessly. The roll attitude was solid through the entire flight. The first stage sep was without impingement.
* The Dragon capsule entered orbit 301×288 on a targeted 300km circular.
* The capsule thrusters were tested on maneuvers similar to what is required for ISS docking.
* 4 Cubesats were successfully released into orbit.
* After separation from Dragon, the Falcon 2nd stage was fired again and placed in an orbit with an 11,000km apogee.
* The capsule re-entry burns were spot on.
* All three parachutes deployed perfectly.
* The capsule came down so close to the recovery ship that they have a good photo of it under the parachutes.
* It was being recovered within 35 minutes of the opening of the drogue chute.
* The heat shield barely got warm. We have now been told that this craft has a heat shield that can handle a free return from the Luna or Mars, i.e. it can be used as an interplanetary vehicle.
* Plans are for the next generation to do powered landings on a helipad sized landing pad.
* The volume and capabilities of Dragon meet or exceed those of the not yet ready for test Orion capsule.
* Today’s mission was so stunningly successful that SpaceX wants to move directly to an ISS flight on the next test. NASA is thinking about it
Today, SpaceX became the first commercial company in history to re-enter a spacecraft from low-Earth orbit.
SpaceX launched its Dragon spacecraft into low-Earth orbit atop a Falcon 9 rocket at 10:43 AM EST from the Air Force Station at Cape Canaveral.
The Dragon spacecraft orbited the Earth at speeds greater than 17,000 miles per hour, reentered the Earth’s atmosphere, and landed in the Pacific Ocean shortly after 2:00 PM EST.
This marks the first time a commercial company has successfully recovered a spacecraft reentering from low-Earth orbit. It is a feat performed by only six nations or government agencies: the United States, Russia, China, Japan, India, and the European Space Agency.
It is also the first flight under NASA’s COTS program to develop commercial supply services to the International Space Station. After the Space Shuttle retires, SpaceX will fly at least 12 missions to carry cargo to and from the International Space Station as part of the Commercial Resupply Services contract for NASA. The Falcon 9 rocket and Dragon spacecraft were designed to one day carry astronauts; both the COTS and CRS missions will yield valuable flight experience toward this goal.
View the press kit: http://www.spacex.com/downloads/cots1-20101206.pdf
The two mile runway at Spaceport America in New Mexico was dedicated Friday, 22 October 2010. One of the highlights of the celebration was the flyover and landing of Virgin Galactic‘s White Knight Two carrying the rocket plane Space Ship Two, named Enterprise by Virgin Galactic.
Governor Bill Richardson of New Mexico, for whom the runway (spaceway) was officially named during the ceremony, commented that:
Sir Richard Branson and approximately 30 of more than 380 Virgin Galactic future astronauts attended the event. Two of the future passengers in attendance were Sonja Rohde from Germany and Perveen Crawford of Hong Kong. Both have already paid the full $200,000 price for their flight into space. “It’s like Christmas, you want to go, you can’t wait. It was always a childhood dream to go to space,” Rohde said. Crawford noted that “It’s a bargain compared to the Russians,” referring to the roughly $35 million past space tourists have paid to ride aboard the Soyuz to the International Space Station.